Elizete Rizzo

Environmental disasters such as the rupturing of mine tailings dams are a major concern worldwide. In the present study, we assess the effects of the release of mine waste due to the rupture of the Fundão dam on two native fish species (Hoplias intermedius and Hypostomus affinis) from the Doce River basin. Two sampling sites were chosen: S1, a reference site, and S2, contaminated by mining waste. Water and sediment were collected to evaluate metals concentration. Adult fish were caught to analyse biological parameters, hepatic histopathology, and biomarkers of metal contamination. Compared to site S1, the concentration of manganese was statistically higher in water while lead, nickel, and arsenic were statistically higher in the sediment from site S2, and iron had no significant difference between sites. At site S1, fish of both species presented hepatic tissue with normal architecture. At site S2, hepatic alterations, such as cytoplasmic vacuolization and necrosis were frequently found in both species. Regarding the histopathological index, higher values were found in both species from site S2. The positive antibody reactions for cytochrome P450 1A (CYP1A) and metallothionein (MT) were statistically greater in site S2 for both species. The oxidative stress biomarkers, superoxide dismutase (SOD) and catalase (CAT) were statistically higher in H. intermedius from site S2, but only CAT was statistically greater in H. affinis at site S2. These results demonstrate that the release of mineral residues from the rupture of the Samarco mine dam is provoking hepatic damage in the fish from the Doce River besides inducing the expression of proteins and enzymes related to metal contamination.

Eggs of 23 Characiformes and eight Siluriformes, belonging to nine families with diverse reproductive behaviour, were ultrastructurally analysed. The migratory species exhibited non‐adhesive eggs, whereas, most of the sedentary species presented some degree of egg adhesiveness. Among the Characiformes, non‐adhesive eggs showed zona radiata with pore‐canals or a fibrillar net at the surface; weakly adhesive eggs presented only zona radiata with pore‐canals while adhesive eggs exhibited zona radiata with apparatus like globules, filaments, villi or honeycomb‐like pores depending on the systematic group. The ‘jelly’ coat is strongly related to the Siluriformes eggs apparently without relationship with adhesiveness. A micropylar disc was present in adhesive eggs of a few species of both Characiformes and Siluriformes. Some patterns were characteristic of the animal pole, others of the vegetal pole, and others were common to both poles. The radial ridges converging to the micropyle in Astyanax bimaculatus lacustris appear to be related to fertilization. In general, egg surface structures in the Characiformes varied according to the genus, whereas all Siluriformes showed a similar egg surface pattern, regardless of the group analysed. Multivariate analysis allowed the identification of eight clusters among the Characiformes and three among the Siluriformes showing relationships between reproductive style and egg characteristics. It is suggested that egg surface and adhesiveness may be related to reproductive patterns and to phylogenesis.

Heavy metals are considered major pollutants of aquatic environments due to the difficulty of metabolization and the bioaccumulative potential in tissues of aquatic organisms, especially fish muscle that is often used as food worldwide. In addition to causing cell damage, some metals such as aluminium (Al), cadmium (Cd), copper (Cu), and lead (Pb) can act as endocrine disrupting chemicals in fish. The Paraopeba and Abaete Rivers are important tributaries of the upper São Francisco River basin, but the Paraopeba River receives, along its course, the discharge of many types of effluents that affect fish species, including widely consumed species such as Prochilodus argenteus. This study evaluated histological and molecular changes caused by chronic exposure to heavy metals in P. argenteus from the Paraopeba River and compared this to fish from the non-impacted Abaete River. Sampled fish from both rivers were used in histological analyses and immunohistochemical assays. The results showed increased incidence of histopathologies and changes in number and morphology of germline cells in both sexes. In addition, up-regulated expression of oestrogens-induced proteins in the liver of males were detected in polluted environment. All the alterations were related to the concentration of metals in water and fish. The high concentration of various metals observed in water and fish from Paraopeba River serves as an alert to the environmental and public health regulatory authorities.

Follicular atresia is a common phenomenon in vertebrate ovaries involving the oocyte and the follicular wall degeneration. Female Astyanax bimaculatus lacustris and Leporinus reinhardti were kept in aquaculture cages inside tanks from February 1994 to January 1995 for the study of the characteristics of different stages of follicular atresia. Histological and ultrastructural analysis demonstrated similarities in the degenerative events and in the resorption of oocytes in both species. Degradation of organelles, such as mitochondria, cortical alveoli, and annulate lamellae occurred in the peripheral ooplasm during the initial stage of the process. Follicle cells showed marked phagocytic activity with digestive vacuoles, myelin figures, and lipofuscin granules during the intermediate and advanced stages of follicular atresia. Granulocytes were in activity during the final stage of follicle resorption. The duration of follicular atresia was 4 months in Leporinus reinhardti and 7 months in Astyanax bimaculatus lacustris. When submitted to induced reproduction in December 1995, 50–60% of the females of both species responded to induced spawning, indicating the recovery of gonadal activity. It is suggested that, in captive conditions, follicular atresia is shorter in total-spawning fishes when compared to those showing partial spawning, and that it has no apparent deleterious effects on induced reproduction in the subsequent cycle.

Oocyte morphology, embryogenesis and early larval development were compared in Hoplerythrinus unitaeniatus , Hoplias lacerdae and Hoplias malabaricus (Characiformes: Erythrinidae) by macroscopical, histological, histochemical and ultrastructural analyses. The eggs of the three species were yellowish and adhesive, containing carboxyl and sulphate radicals in the glycoconjugates of the zona radiata. A complex surface arrangement was identified in oocytes of H. unitaeniatus and H. lacerdae , while H. malabaricus had a simple oocyte surface pattern. Lectin histochemistry revealed different carbohydrate terminal residues in cortical alveoli, outer zona radiata and follicular cells of the three species. At the animal pole, the oocyte surface topography surrounding the micropyle was species‐specific. The micropylar cell was ConA‐positive, suggesting the presence of carbohydrates with mannose/glucose terminal residues that could have a role during fertilization. The erythrinids exhibited a prolonged embryonic and larval development compared to other Characiformes, a reproductive strategy used for increasing offspring protection. Early development proceeded most rapidly in H. unitaeniatus , followed by H. malabaricus and then H. lacerdae , which could have more developed parental care behaviour. An adhesive organ composed of secretory prismatic cells protruding from the cephalic region of the three erythrinid larva allowed them to attach to one another during development. Reproductive behaviour and early developmental strategies were similar in the three species, but the oocyte surface morphology suggests a close relationship between H. unitaeniatus and H. lacerdae .

We investigated apoptosis, cell proliferation antigen (PCNA), and heat shock protein (HSP70) during ovarian follicular atresia in two freshwater teleost species from the São Francisco River basin, Brazil: curimatã-pacu, Prochilodus argenteus and piau-jejo, Leporinus taeniatus. Fishes were maintained in captivity after the reproductive period and ovarian regression was assessed by gonadosomatic index for three stages: early, advanced, and late regression. Follicular atresia was analysed by light and transmission electron microscopy, as well as by TUNEL and immunohistochemistry for HSP70 and PCNA. During early regression, atretic follicles exhibited zona pellucida breakdown, yolk degeneration, and hypertrophied follicular cells (e.g. granulosa in mammals). Intense heterophagy to engulf the yolk, and autophagy were detected in the follicular cells during advanced and late atresia. The TUNEL assay detected DNA fragmentation, mainly in late follicular atresia. The apoptosis rate of the follicular cells increased up to 10% during follicular atresia in both species and was negatively correlated with follicular area. Immunohistochemistry reaction for HSP70 stained the follicular cells strongly during advanced atresia, when they are intensively involved in yolk engulfment, whereas the reaction for PCNA labelled theca cells. We inferred that heterophagy, autophagy, and apoptosis contributed to follicular atresia in teleost ovaries, thereby achieving a more efficient removal of the degenerating oocyte and dying follicular cells. Additionally, HSP70 may protect the follicular cells before apoptosis when they are involved in yolk engulfment, and cell proliferation in the theca contributed to ovarian remodelling.

Journal of Applied IchthyologyVolume 25, Issue 3 p. 306-313 Reproductive biology of Astyanax fasciatus (Pisces: Characiformes) in a reservoir in southeastern Brazil P. A. De Carvalho, P. A. De Carvalho Graduate Program Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this authorA. L. Paschoalini, A. L. Paschoalini Graduate Program Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this authorG. B. Santos, G. B. Santos Graduate Program Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this authorE. Rizzo, E. Rizzo Institute of Biological Sciences, Federal University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this authorN. Bazzoli, N. Bazzoli Graduate Program Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this author P. A. De Carvalho, P. A. De Carvalho Graduate Program Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this authorA. L. Paschoalini, A. L. Paschoalini Graduate Program Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this authorG. B. Santos, G. B. Santos Graduate Program Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this authorE. Rizzo, E. Rizzo Institute of Biological Sciences, Federal University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this authorN. Bazzoli, N. Bazzoli Graduate Program Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Minas Gerais, BrazilSearch for more papers by this author First published: 18 May 2009 https://doi.org/10.1111/j.1439-0426.2009.01238.xCitations: 51 Author's address: Nilo Bazzoli, Graduate Program in Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais, Brazil, Av. Dom José Gaspar, 500, Coração Eucarístico, CEP 30535-610, Belo Horizonte, Minas Gerais, Brazil.E-mail: bazzoli@pucminas.br Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Summary To study the reproductive biology of Astyanax fasciatus (Cuvier, 1819) in Furnas Reservoir, Minas Gerais, Brazil, a total of 1307 specimens were captured in bimonthly sampling from August 1993 to July 1994. The sex ratio showed a predominance of females, representing 65.2% of the total sample. The stages of gonadal maturation and spawning type were determined through macro- and microscopic analysis of the gonads as well as by variation in the gonadosomatic indices. A. fasciatus showed fractionated spawning and reproduction throughout the year, with spawning peaks influenced by water temperature and rainfall. Males and females initiated gonadal maturation at a mean standard length of 6.4 and 6.5 cm, respectively. During gonadal maturation, females showed a reduction in hepatosomatic index (from 1.06 to 0.83), suggesting that hepatic substances are transferred from the liver to the ovaries. In the reproductive period, A. fasciatus had lower stomach repletion and coelomic fat indices, indicating that this species ate less and consumed more fat reserves when reproduction had the maximum GSI (11.3 for females and 2.7 for males). Weight of the ovaries had a positive influence on the condition factor (K1), as the lowest K2 value (weight without gonads) were obtained during maturation, confirming the influence of the ovaries upon the physiological condition of the females. In weight–length relationship, parameter b was 3.02 for females and 2.23 for males, and the correlation coefficient (r2) was 0.84 and 0.66, respectively. Citing Literature Volume25, Issue3Special Issue: Special Issue: Modern Fisheries Research Approaches in BrazilJune 2009Pages 306-313 RelatedInformation

The aim of this study was to assess the health indicators and reproductive endpoints in a wild population of lambari Astyanax fasciatus, a small characid fish widely distributed in South America. A range of biomarkers, from the molecular to population levels, was evaluated in adult fish sampled from five sites from the Furnas Reservoir, Grande River. At the sites that receive untreated agriculture and industrial residues, fish showed reduced body size and delayed gonadal maturation. Fish from the sites located immediately downstream from the municipal wastewater discharges exhibited feminisation, intersex and evidence of contamination by xenoestrogens. Elevated levels of zona radiata proteins were found by Western blot in the livers of male fish from three contaminated sites. Overall, this study provides the first evidence of endocrine disruption in a wild fish population inhabiting the Furnas Reservoir, and suggests water contamination by oestrogenic compounds and agricultural residues with a possible risk to human health and wildlife.

River Research and ApplicationsVolume 21, Issue 8 p. 939-950 Research Article Influence of the Abaeté River on the reproductive success of the neotropical migratory teleost Prochilodus argenteus in the São Francisco River, downstream from the Três Marias Dam, southeastern Brazil Yoshimi Sato, Yoshimi Sato Hydrobiology and Fishculture Station of Três Marias, Minas Gerais—CODEVASF, BrazilSearch for more papers by this authorNilo Bazzoli, Nilo Bazzoli Graduate Program on Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais (PUC-Minas), BrazilSearch for more papers by this authorElizete Rizzo, Corresponding Author Elizete Rizzo [email protected] Department of Morphology, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), BrazilDepartment of Morphology, ICB-UFMG, PO Box 486, 30161-970, Belo Horizonte, MG, Brazil.Search for more papers by this authorMaria Beatriz Boschi, Maria Beatriz Boschi Brazilian Institute for the Environmental and Renewable Natural Resources (IBAMA), BrazilSearch for more papers by this authorMario O. T. Miranda, Mario O. T. Miranda Brazilian Institute for the Environmental and Renewable Natural Resources (IBAMA), BrazilSearch for more papers by this author Yoshimi Sato, Yoshimi Sato Hydrobiology and Fishculture Station of Três Marias, Minas Gerais—CODEVASF, BrazilSearch for more papers by this authorNilo Bazzoli, Nilo Bazzoli Graduate Program on Zoology of Vertebrates, Pontifical Catholic University of Minas Gerais (PUC-Minas), BrazilSearch for more papers by this authorElizete Rizzo, Corresponding Author Elizete Rizzo [email protected] Department of Morphology, Institute of Biological Science, Federal University of Minas Gerais (ICB/UFMG), BrazilDepartment of Morphology, ICB-UFMG, PO Box 486, 30161-970, Belo Horizonte, MG, Brazil.Search for more papers by this authorMaria Beatriz Boschi, Maria Beatriz Boschi Brazilian Institute for the Environmental and Renewable Natural Resources (IBAMA), BrazilSearch for more papers by this authorMario O. T. Miranda, Mario O. T. Miranda Brazilian Institute for the Environmental and Renewable Natural Resources (IBAMA), BrazilSearch for more papers by this author First published: 12 August 2005 https://doi.org/10.1002/rra.859Citations: 58AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Abstract The curimatã-pacu Prochilodus argenteus is an important characiform from the São Francisco River basin that performs long-distance migrations for spawning upstream during the rainy season, when the temperature and photoperiod are elevated. Despite the interruption of the migratory routes by the Três Marias Dam and accentuated decline in fishing, the curimatã-pacu still sustains the fisheries at the Três Marias region in recent decades. The objective of this study was to evaluate the reproductive activity of P. argenteus in two sections of the São Francisco River, downstream from the Três Marias Dam, during the rainy season. In the first 34 km of the river, immediately below the dam, most of the females were in gonadal resting. At 34–54 km downstream from the dam, following the confluence with a medium-sized tributary, the Abaeté River, there was a high frequency of males and females in reproductive activity. Follicular atresia was more frequent in the upper section of the river while postovulatory follicles occurred predominantly in the lower section. Fulton's condition factor and gonadosomatic index indicated that the females were in a better physiological and reproductive condition below the confluence with the Abaeté River. In contrast to the females, the males were less affected by damming, and testicular maturation was largely achieved in two river sections. Thus, although the section of the São Francisco River immediately below the Três Marias Dam was found to be unfavourable for the reproduction of the migratory fishes due principally to the hypolimnetic water from the reservoir, reproductive success of P. argenteus was achieved below the Abaeté River. In this section, the species encountered appropriate conditions for maturation and spawning, i.e. warm temperatures above 24°C, high water flow and dissolved oxygen, and low water transparency. These results indicate the importance of a non-regulated tributary to minimize the ecological impact of a dam on the downstream native fish communities. Copyright © 2005 John Wiley & Sons, Ltd. Citing Literature Volume21, Issue8October 2005Pages 939-950 RelatedInformation

The silver catfish, Rhamdia quelen, is endemic to North, Central and South America with high aquaculture potential and wide acceptance in the market. Breeder fish were subjected to induced reproduction through hypophysation using a crude common carp pituitary extract. Egg characteristics, oocyte surface ultrastructure and histology of larval ontogenesis until whole yolk resorption were described for the first time for this species. Oocytes and semen were obtained by manual extrusion, and fertilization was conducted using the dry method. After fertilization, eggs were kept in incubators at 24 °C. The embryonic development was monitored using a stereomicroscope every 10 min until hatching. To analyse the larval development, larvae samples were collected from incubators daily until the fifth day, fixed in Bouin's fluid and subjected to routine histological techniques. The oocyte extrusion occurred 8 h after the second hormone dose at 26 °C. The oocytes were spherical, non-adhesive and yellow, with a diameter of 1471.75±47.63 μm. Scanning electron microscopy revealed a thin jelly coat covering the zona radiata in the animal pole around the micropyle. The blastopore closure occurred within 8 h after fertilization, and the fertilization rate was 79.9±5.2% at 24 °C. Embryonic development was completed within 25 h 30 min after fertilization. The complete resorption of the yolk and the formation of the digestive system organs and the mouth opening occurred on the fifth day, indicating a need for exogenous feeding. The results of this study provide information important for improvement in R. quelen culture and management.

The present study evaluated for the first time sex steroid profiles and fecundity in females of Prochilodus argenteus from two sections of the São Francisco River Brazil, downstream from the Três Marias Dam, which influences characteristics of their water habitat. The model species in the study, P. argenteus, is an important commercial and recreational species in Brazil. In the region closest to the dam (section 1), females did not reach final oocyte maturation, failed to spawn, and displayed lesser circulating concentrations of testosterone, 17(-hydroxyprogesterone (17(-P) and 17β-estradiol (E2) than those farther downstream of the dam (section 2). The endocrine and fecundity deficiencies probably are attributed to lower water temperature and oxygen concentration in (section 1). The follicular atresia rate in the region closest to the dam (26%) was greater than those fish captured farther downstream of the dam (13%), after the Abaeté River (section 2). Variations in testosterone, E2 and 17(-P concentrations in section 2, followed gonadal maturation which are typical features of species which have seasonal reproduction, group-synchronous oocyte development, and are single batch spawners such as P. argenteus. Results document the first evidence of endocrine and reproductive dysfunctions caused by inadequate water conditions in a wild population of the migratory species P. argenteus in the São Francisco River, downstream from the Três Marias dam.

Aiming to better understand folliculogenesis, this study evaluated cell death and proliferation of ovarian cells, besides cathepsin-D expression in Prochilodus argenteus captured in two sites of the São Francisco River downstream from the Três Marias Dam, Brazil. In the site immediately following the Dam (S1), low levels of dissolved oxygen were registered in the rainy period. The water temperature was higher in the São Francisco River immediately after the confluence with the Abaeté River (S2), regardless of the period. In S1, the ovaries showed smaller oocytes, high caspase-3 enzymatic activity and apoptosis, lower cells in proliferation and GSI, as well as a lesser quantity of cathepsin-D when compared to females captured from S2. Regarding relative frequency of ovarian structures, in the dry period, only oogonia and perinucleolar oocytes were found in fish ovaries from both sites. On the other hand, in the rainy period, the relative frequency of oogonia and perinucleolar oocytes decreased and the vitellogenic oocytes increased in S2. Postovulatory follicles were observed only in S2, whereas atretic follicles occurred at a higher frequency in S1. Our results showed that apoptosis, cell proliferation and cathepsina-D evaluation can be used as biomarkers of environmental impact.

Pollutants found dispersed in water can cause irritations on the gills, challenge the immune system and prejudice the welfare of the fish. Here we investigated molecules linked to proliferation, survival, and cell death, as well as inflammatory and vascular control, in a model of fish gill remodeling, from injury to recovery. We assessed the gill histology and immunohistochemistry for PCNA, iNOS, HSP70, and Bax in Hypostomus francisci obtained from a river subjected to chronic anthropic influences and then after they were placed in water of good quality. A total of 30 H. francisci adult individuals were collected and distributed into two groups: euthanized on the day of capture (group 1) and maintained for 30 days in an aquarium (group 2). In all the fish from group 1, the primary and secondary lamellae showed hypertrophy of the respiratory epithelium, lamellar fusion, lifting of the epithelium, aneurysm, hyperemia, and vascular congestion. On the other hand, in all the fish from group 2, restoration of gill integrity was observed, and the primary and secondary lamellae showed a simple epithelium, absence of lamellar fusion, hypertrophy, and aneurysm. Gills of fish from group 1 had higher frequency of cells immunopositive for PCNA, iNOS, HSP70, and Bax than those of fish from group 2 (p < 0.05). The molecular and cellular mechanisms from injury to recovery were proposed, with a balance between survival and cell death signals being essential for determining the gill structure. In addition, the findings indicate that recovery of the structural organization of gills is possible if fishes are maintained in good-quality water, indicating the importance of the conservation of aquatic environments.

Studies on fish reproduction and early development are important to establish measures of conservation of ichthyofauna and to develop fish farming with native species. This chapter addresses the parameters of reproductive biology and embryogenesis of fish from the São Francisco and Grande River basins, Brazil. The size of sexual maturation, the breeding season, gonadal maturation, spawning type, egg adhesiveness, fecundity, egg size, and the times of blastopore closure and hatching are compared in different Characiformes, Siluriformes, and Perciformes fish species. The data presented here were obtained from 1990 to 2018 by the following research groups: Fish Reproduction of the Federal University of Minas Gerais (UFMG) and Ecology and Conservation of Freshwater Resources of the Pontifical Catholic University of Minas Gerais (PUC-Minas). These data are the result of several research projects developed in collaboration with undergraduate and graduate students, which contributed greatly to improving the knowledge of neotropical fish biology.

The gametogenesis of Bryconops affinis was studied by light, transmission and scanning electron microscopy. The spermatogenesis is semi-cystic and spermatids are released into the lumen of seminiferous tubules, where spermiogenesis is completed. Spermatozoa have an ovoid head, a rudimentary middle piece with a small number of mitochondria and long flagellum (primitive spermatozoa). The Sertoli and Leydig cells show secretory activity during spermatogenesis. By the end of this phenomenon, the Sertoli cells phagocytize the residual spermatozoa, while the Leydig cells show involuted characteristics. With regard to the oogenesis process, the oocyte development was divided into four stages based on the cytological characteristics of the oocyte and its surrounding layers. Ultrastructural analysis revealed that the zona pellucida is formed during the previtellogenic stage. Specializations associated to the outer layer of the zona pellucida may be related to the egg's adherence to the substrata.

This is the first evidence of programmed cell death, or apoptosis, occurring in the postovulatory follicle (POF) of teleost fish. Females of Astyanax bimaculatus lacustris were submitted to induced ovulation through injecting pituitary extract. Ultrastructural analyses of POFs at time intervals varying from zero to four days postspawning showed several characteristic events of the apoptosis. Typical apoptotic figures, such as nucleus with chromatin condensation underlying the nuclear envelope in a crescent pattern and apoptotic bodies at different stages of formation and reabsorption, were observed in the follicular cells a few days after the onset of the postovulatory period. The results indicated that apoptosis is the major mechanism responsible for the elimination of the follicular cells in the POFs of A. bimaculatus lacustris during ovarian recovery postspawning. It is suggested that POFs might be used as an experimental model in dynamic studies involving cell death in teleosts.

AbstractAutophagy, a highly conserved catabolic program for degrading proteins and organelles, is essential for cell and tissue homeostasis. Primarily, this process has a cytoprotective role under nutrient deprivation, but several stress stimuli can induce autophagy and, thus, distinct programmed cell death (PCD) pathways can be actived when stress is not abolished. Fish ovaries are a suitable experimental model system for studying the mechanisms of PCD due to the presence of postovulatory and atretic (i.e., non-ovulated) follicles, which follow different routes after spawning. Apoptosis of the follicular cells is the major mechanism responsible for the rapid resorption of the postovulatory follicles. Recently, we investigated the contribution of PCD during follicular atresia in two species of freshwater fish. In contrast to mammals, this study revealed that follicular apoptosis is not a major process for deletion of follicular cells in atretic follicles. Furthermore, we detected autophagic vacuoles containing degenerating organelles increasing through follicular atresia in both species. In this addendum, we propose a hypothesis for follicular cell removal during ovarian regression in oviparous fish. In this model, autophagy could have dual roles in follicular atresia. Thus, fish ovaries after breeding are suitable models for studying the interactions among the different cell death pathways.This article refers to:

We studied the relationship between the morphology of the reproductive system and the reproductive strategies of six neotropical catfishes using macroscopic and microscopic analyses. The reproductive system of the examined Siluriformes showed diversified characteristics, but permitted their being grouped according to three reproductive strategies: pelagic spawning, demersal spawning, and internally fertilizing. The pelagic spawners Pseudoplatystoma corruscans and Conorhynchos conirostris have testes that are characterized by filiform lobes, absence of testicular secretion, full-grown oocytes of small diameter, thin zona radiata, and cuboidal follicular cells. Pimelodus maculatus is morphologically distinct from the other two pelagic spawners catfishes due to the presence of testicular secretion. The demersal spawners Lophiosilurus alexandri and Rhinelepis aspera possess homogeneous testicular secretion, large mature oocytes, and columnar follicular cells. The most specialized reproductive system was observed in the internally fertilizing Trachelyopterus galeatus, which possesses a seminal vesicle accessory to the testes, spermatozoa with elongated nuclei that form spermatozeugmata, and a secretory ovarian lamellar epithelium that is associated with sperm storage. The reproductive system observed in Neotropical catfishes showed a relationship associated with the type of fertilization and the reproductive strategies of the six species studied.

A total of 312 adults of matrinxã were captured bimonthly, between 2011-2012, in two sites of the rio São Francisco: immediately downstream of the Três Marias Dam (site 1) and in the confluence with the rio Abaeté (site 2). Specimens of Brycon orthotaenia from site 2 presented higher values of total length (32.24 ± 5.70 cm for females and 26.64 ± 3.79 cm for males) and body weight (506.66 ± 332.17 g for females and 267.36 ± 145.84 g for males), when compared with the site 1. In site 2 was registered the highest GSI means (9.97 ± 2.96 for females and 0.93 ± 0.52 for males), compared with the site 1 means. Reproduction period occurred from October to February. Unlike site 2, no spawned females or spent males were captured in site 1. Significant differences were found between females and males in site 2 (χ2 = 26.84, df = 1, P &lt; 0.05). Physical-chemical parameters of the water presented higher values in site 2. The canonical correlation test indicated that the reproduction of males is less susceptible to environmental factors than that of females. These results show that B. orthotaenia finds favourable conditions to reproduction just in site 2.

The present study assessed the influence of salinity and temperature on body growth and on muscle cellularity of Lophiosilurus alexaxdri vitelinic larvae. Slightly salted environments negatively influenced body growth of freshwater fish larvae and we observed that those conditions notably act as an environmental influencer on muscle growth and on local expression of hypertrophia and hypeplasia markers (IGFs and PCNA). Furthermore, we could see that salinity tolerance for NaCl 4 g l−1 diminishes with increasing temperature, evidenced by variation in body and muscle growth, and by irregular morphology of the lateral skeletal muscle of larvae. We saw that an increase of both PCNA and autocrine IGF-II are correlated to an increase in fibre numbers and fibre diameter as the temperature increases and salinity diminishes. On the other hand, autocrine IGF-I follows the opposite way to the other biological parameters assessed, increasing as salinity increases and temperature diminishes, showing that this protein did not participate in muscle cellularity, but participating in molecular/cellular repair. Therefore, slightly salted environments may provide adverse conditions that cause some obstacles to somatic growth of this species, suggesting some osmotic expenditure with a salinity increment.

The Velhas River is the most polluted river in the state of Minas Gerais, south-eastern Brazil. Due to its historical and environmental relevance, the aim of this study was to evaluate the effects of oestrogenic endocrine disruptors on the reproduction of the lambari Astyanax rivularis, a small-sized species found in headwaters of the São Francisco River basin. Quarterly field samplings were carried out during a reproductive cycle in three streams of the upper Velhas River: S1 (reference site) and S2 and S3 (sites contaminated by untreated sewage). The main oestrogenic compounds were evaluated in water using HPLC/MS. Molecular, histological and reproductive biomarkers were assessed in liver and gonad. The results showed higher average concentrations of oestradiol (>200ng/l) in S2 and S3, oestrone (>250ng/l) in S2 as well as oestriol (>200ng/l), bisphenol A (>190ng/l), and nonylphenol (>600ng/l) in S3 compared to S1 (<70ng/l for all compounds). In S2 and S3, there was an increase in the proportion of females, higher ELISA levels of vitellogenin (Vtg) and proteins of the zona radiata (Zrp) in liver males. Insulin-like growth factor (IGF-I) levels were lower in S2 males, which also had a smaller body size, a smaller seminiferous tubule diameter, a higher proportion of spermatogonia, and lower proportion of spermatozoa in relation to S1. Histopathological analyses detected an increase in yolk deficient oocytes and over-ripening in the contaminated sites, and these alterations were associated to a reduction of hepatic Vtg levels and a delay in spawning, respectively. Intersex specimens with perinucleolar follicles in a multifocal distribution in the testis were detected in S2 and S3. These results indicate that chronic exposure to oestrogenic compounds induced endocrine disruption that may affect wild populations of A. rivularis in the Velhas River.

The loss of oocyte viability after ovulation is one of the limiting factors in controlled reproduction of several fish species. Experiments were performed with 15 feral Prochilodus marggravii female fish induced to spawn with crude carp pituitary extract to evaluate the viability of oocytes retained within the ovarian cavity (in situ storage) and outside of the ovarian cavity (ex situ storage). Because fertility rates rapidly declined after ovulation, simultaneously with an increase in the number of deformed larvae, P. marggravii oocytes could only be successfully stored for 1 h ex situ at room temperature ( approximately 26 degrees C). There was a highly negative correlation (r = -0.82) between fertilization and deformed larvae during in situ storage at approximately 26 degrees C. Ex situ cooling (18 degrees C) caused a drastic reduction in fertilization rates as compared with storage at approximately 26 degrees C. Oocyte structure was preserved during 2 h storage and the cortical reaction was induced before spawning. Since the micropylar apparatus remained open, it was not the primary cause for the loss of oocyte fertility. The cytoskeleton of the oocyte appeared to be affected since ooplasmic segregation was altered after 2 h storage.

Involution and resorption of both postovulatory and atretic follicles were analysed in piau‐jejo Leporinus taeniatus (Characiformes, Anostomidae) in order to evaluate the role of apoptosis during ovarian regression. Histological and ultrastructural analyses showed hallmarks of apoptosis in the granulosa: aggregation of compacted chromatin against the nuclear envelope, cell shrinkage, surface blebbing, loss of cell adhesion and cell fragmentation into apoptotic bodies. Protein synthesis activity preceded the onset of the cell death. The breakdown of the basement membrane led to the detachment of the granulosa cells into the follicular lumen. TUNEL‐positive reactions were detected in in situ DNA fragmentation of granulosa of both postovulatory and atretic follicles. Apoptosis increased in a time‐dependent manner contributing to reduction of the follicular areas. The apoptotic index (per cent of apoptotic cells) of the granulosa increased in postovulatory follicles soon after spawning, then these follicles degenerated and only remnants were observed at 7 days. In contrast, the granulosa cells reabsorbed the yolk during follicular atresia and the apoptotic index increased only in the late stage of regression. The results indicated apoptosis as the major mechanism to rapidly eliminate postovulatory follicles and being an essential process in the ovarian regression after spawning.

An anatomical, histological and ultrastructural study was made of the reproductive system and spermatogenesis of Iheringichthys labrosus. The testis are digitiform and consist of a sperm atogenic cranial region, a spermatogenic/secretory medial (transition) region, and a strictly secretory caudal region. The cranial region represents 66% of the total length of the maturing testis and its fringes or lobes have a length of 5.59 + 0.73 mm. The medial and caudal regions represent each 17% of the testicular length and their fringes have a length of 5.37 +/- 0.69 mm and 3.12 +/- 0.38 mm, respectively. Histologically, the cranial region of the testis is made up of seminiferous tubules with spermatogenic cells contained in cysts. These cells undergo synchronous development, inside the cysts where spermatogenesis is completed. The secretory caudal region does not constitute an individualized gland. Ultrastructurally, its secretory cells have a vesiculous nucleus and a cytoplasm with abundant dilated cisternae of rough endoplasmic reticulum. The caudal region produces a glycoproteic secretion and exhibits variable electron density during maturation. During the resting period, these cells are poor in synthesis organelles. The spermatozoa are of the primitive type, with a round head (1.56 +/- 0.11 microm), a rudimentary middle piece, and a long flagellum with a 9 + 2 axonemal arrangement.

The black armoured catfish Rhinelepis aspera is an important commercial species found in the São Francisco River (Brazil) that has great potential for pisciculture. This paper presents, for the first time, information on the embryogenesis and larval development of this species. The breeder fish were subjected to spawning induction with crude carp pituitary extract. Eggs were kept in incubators at 24 degrees C and embryogenesis was observed with a stereomicroscope until hatching. Ovary fragments, samples of recently extruded oocytes and larvae were fixed in Bouin's solution and subjected to routine histology techniques. Recently extruded oocytes were also analyzed with a scanning electron microscope (SEM). Females (80%) had a positive response to hypophysation. Oocyte extrusion was performed at 8 h and 30 min after the second hormone injection and the fertilization rate achieved 72.4 +/- 8.8%. Recently extruded oocytes had a mean diameter of 1360.80 +/- 40.87 microm and presented a conspicuous jelly coat covering the zona pellucida. Histochemical reactions indicated the presence of neutral glycoproteins in the yolk globules and in the zona pellucida. These reactions also indicated the presence of neutral glycoproteins and carboxylated acid glycoconjugates in the follicular cells and the jelly coat. These compounds form mucosubstances that can be related to the adhesiveness of the eggs. Under the SEM the oocytes presented a micropyle disc and a thick jelly coat over their surface. The closure of the blastopore occurred 9 h and 40 min after fertilization and embryogenesis was completed at 45 h and 50 min after fertilization, when the embryos were incubated at 24 degrees C. The total absorption of the yolk sac occurred during the fifth day indicating the need for an exogenous food supply. These results provide essential information for the successful breeding and management of the promising R. aspera.

Anticancer drug research based on natural compounds enabled the discovery of many drugs currently used in cancer therapy. Here, we report the in vitro, in vivo and in silico anticancer and estrogen-like activity of Psidium guajava L. (guava) extracts and enriched mixture containing the meroterpenes guajadial, psidial A and psiguadial A and B. All samples were evaluated in vitro for anticancer activity against nine human cancer lines: K562 (leukemia), MCF7 (breast), NCI/ADR-RES (resistant ovarian cancer), NCI-H460 (lung), UACC-62 (melanoma), PC-3 (prostate), HT-29 (colon), OVCAR-3 (ovarian) and 786-0 (kidney). Psidium guajava’s active compounds displayed similar physicochemical properties to estradiol and tamoxifen, as in silico molecular docking studies demonstrated that they fit into the estrogen receptors (ERs). The meroterpene-enriched fraction was also evaluated in vivo in a Solid Ehrlich murine breast adenocarcinoma model, and showed to be highly effective in inhibiting tumor growth, also demonstrating uterus increase in comparison to negative controls. The ability of guajadial, psidial A and psiguadials A and B to reduce tumor growth and stimulate uterus proliferation, as well as their in silico docking similarity to tamoxifen, suggest that these compounds may act as Selective Estrogen Receptors Modulators (SERMs), therefore holding significant potential for anticancer therapy. Keywords: Active principles, cancer, P. guajava L. (guava), phytoestrogens, SERM, tamoxifen.

Although herbicides have been developed to act on the physiological processes of plants, they are responsible for causing deleterious effects on animals. These chemical compounds are widely used throughout the world, but especially in countries that export agricultural products such as Central and South America, their use has increased in recent years. Aquatic environments are natural reservoirs of herbicides, which after being applied on crops, run off through the soil reaching rivers, lakes, and oceans. Fish are among the many organisms affected by the contamination of aquatic environments caused by herbicides. These animals play an important ecological role and are a major source of food for humans. However, few studies address the effects of herbicides on fish in this region. Thus, in the present review we discuss the morphophysiological and molecular consequences of herbicide exposure in Neotropical fish systems as well as how the environmental and land use characteristics in this region can influence the toxicity of these pollutants. A toxicity pathway framework was developed summarizing the mechanisms by which herbicides act and endpoints that need to be further investigated.

Lead (Pb) is an emerging contaminant widely distributed in aquatic environments, which has serious effects on human and animal health. In this study, we determined whether Pb exposure affects gametogenesis, sex steroids, estrogen (ERα and ERβ), and androgen (AR) receptors. Adult specimens of Astyanax bimaculatus were exposed in duplicate to 15, 50, and 100 μg/L of lead acetate, whereas the control group was not exposed. After 28 days of exposure, fish were euthanized and samples of the gonads, liver, and blood were collected for analysis. The results indicated a reduction in the gonadosomatic index as well as the diameters of the vitellogenic follicles and seminiferous tubules in the exposed groups. Morphometry of gametogenesis revealed inhibition of the secondary oocyte growth and a reduction in the number of spermatozoa in the 50 and 100 μg/L Pb-treated groups. In females, plasma 17β-estradiol (E2) increased following 15 and 50 μg/L Pb treatment, whereas males exhibited an increase in E2 and 11-ketotestosterone following treatment with 15 and 100 μg/L Pb, respectively. Vitellogenin was significantly reduced in females exposed to 100 μg/L Pb, but metallothionein levels were unchanged. ERα, ERβ, and AR were immunolocalized in the somatic and germ cells, with increased ovarian expression of ERα and Erβ in the 100 μg/L Pb-treated group, but no significant difference in AR among the groups. In males, only ERα increased in the 100 μg/L Pb-treated group. These results indicate that Pb exposure impairs gametogenesis, disrupts estrogen receptor signaling, and affects the expression of major reproductive biomarkers in A. bimaculatus.

Reproductive biology and feeding of Curimatella lepidura (Eigenmann &amp; Eigenmann, 1889) were studied in Juramento reservoir, São Francisco River basin, Southeastern Brazil. Histological analyses and gonadosomatic indexes revealed females and males in reproductive activity from October to March and total spawning occurring from January to March coupled with the peak of spermiating males. In the dry season, the fishes accumulated energetic reserves for reproduction during a short rainy season. The species presented sexual dimorphism, being females larger than males and sexual maturation occurring close to 7.7 cm standard length for females and 7.1 cm for males. C. lepidura presented iliophagous feeding habit, ingesting mainly sediment/detritus and a small amount of acari, algae, Tricoptera insects and Ostracoda crustaceans, suggesting a probable role in nutrient recycling of the Juramento reservoir.

Journal of Applied IchthyologyVolume 25, Issue 3 p. 299-305 Reproduction and fecundity of tucunaré, Cichla kelberi (Perciformes: Cichlidae), an exotic species in Três Marias Reservoir, Southeastern Brazil F. T. Normando, F. T. Normando Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Coração Eucarístico, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorF. P. Arantes, F. P. Arantes Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorR. K. Luz, R. K. Luz Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Coração Eucarístico, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorR. G. Thomé, R. G. Thomé Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorE. Rizzo, E. Rizzo Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorY. Sato, Y. Sato Estação de Hidrobiologia e Piscicultura de Três Marias-CODEVASF, Três Marias, Minas Gerais, BrazilSearch for more papers by this authorN. Bazzoli, N. Bazzoli Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Coração Eucarístico, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this author F. T. Normando, F. T. Normando Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Coração Eucarístico, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorF. P. Arantes, F. P. Arantes Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorR. K. Luz, R. K. Luz Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Coração Eucarístico, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorR. G. Thomé, R. G. Thomé Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorE. Rizzo, E. Rizzo Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorY. Sato, Y. Sato Estação de Hidrobiologia e Piscicultura de Três Marias-CODEVASF, Três Marias, Minas Gerais, BrazilSearch for more papers by this authorN. Bazzoli, N. Bazzoli Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Coração Eucarístico, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this author First published: 18 May 2009 https://doi.org/10.1111/j.1439-0426.2008.01174.xCitations: 22 Author's address: Nilo Bazzoli, Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Av. Dom José Gaspar, 500, Coração Eucarístico, Prédio 41, 30535-610 Belo Horizonte, Minas Gerais, Brazil.E-mail: [email protected] Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Summary To evaluate the reproductive cycle and fecundity of tucunaré (Cichla kelberi Kullander & Ferreira, 2006), 697 specimens were captured in Três Marias Reservoir, São Francisco River, Brazil during 1994–1995 and 2005–2006. Reproductive activity was recorded throughout the sampling periods, with females exhibiting asynchronous oocyte development and multiple spawnings with a peak in September–October. Vitellogenic oocytes of the tucunaré were elliptical in shape with the longest diameter approximately 1230 μm and the shortest 700 μm, yolk globules with ellipsoid inclusions, lipid vesicles, small cortical alveoli and thin zona radiata (9.3 ± 2.0 μm thickness). Follicular cells were prisma-shaped (49.0 ± 16.4 μm) in the vegetative pole, progressively becoming cubic cells in the animal pole toward the micropyle. Histochemical analyses indicated the presence of mucosubstances in the outer zona radiata and follicular cells that could be contributors to egg adhesiveness. Batch fecundity ranged from 4450 to 13 900 oocytes for females 31.5–43.5 cm total length, respectively, and correlated to gonadal weight (r2 = 0.80) and body weight (r2 = 0.70). Mean relative fecundity was 10.6 vitellogenic oocytes per gram body weight. As tucunaré is an exotic piscivorous species well-adapted to the Três Marias Reservoir, the present work may be considered a contribution toward future strategies for population control. References Alberts, B.; Johnson, A.; Lewis, J.; Raff, M.; Roberts, K.; Walter, P., 2002: The molecular biology of the cell, 4th edn. Garland Publishing, New York, 1463 pp. Almatar, S. M.; Lone, K. P.; Abu-Rezq, T. S.; Yousef, A. A., 2004: Spawning frequency, fecundity, egg weight and spawning type of silver promfret, Pampus argenteus (Euphrasen) (Stromateidae), in Kuwait waters. J. Appl. Ichthyol. 20, 176– 188. Andrade, R. F.; Sato, Y.; Rizzo, E.; Ferreira, R. M. A.; Bazzoli, N., 1996: Aspectos da biologia reprodutiva da corvina Pachyurus squamipinnis Agassiz, 1829 (Teleostei, Sciaenidae) na represa de Três Maria. Arq. Bras. Med. Vet. Zoot. 48, 77– 84. Andrade, R. F.; Bazzoli, N.; Rizzo, E.; Sato, Y., 2001: Continuous gametogenesis in the neotropical freshwater teleost, Bryconops affinis (Pisces: Characidae). Tissue Cell 33, 524– 532. Bagenal, T. B.; Braum, E., 1978: Eggs and early life history. In: Methods of assessment of fish production in fresh waters. IBP Handbook 3. T. B. Bagenal (Ed.). Blackwell Scientific, Oxford, pp. 165– 201. Bazzoli, N., 2003: Parâmetros reprodutivos de peixes de interesse comercial. In: Águas, peixe e pesca no São Francisco das Minas Gerais. H. P. Godinho and A. L. Godinho (Eds). Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil, pp. 291– 306. Bazzoli, N.; Godinho, H. P., 1994: Cortical alveoli in oocytes of freshwater neotropical teleost fish. Boll. Zool. 61, 301– 308. Bazzoli, N.; Godinho, H. P., 1995: Comparative morphology of the yolk nucleus (Balbiani body) in freshwater neotropical teleost fish. Rev. Bras. Biol. 55, 207– 214. Brown-Peterson, N. J.; Peterson, M. S.; Nieland, D. L.; Murphy, M. D.; Taylor, R. G.; Warren, J. R., 2002: Reproductive biology of female spotted sea trout, Cynoscion nebulosus, in the Gulf of Mexico: differences among estuaries? Environ. Biol. Fish. 63, 405– 415. Campos-Mendoza, A.; McAndrew, B. J.; Coward, K.; Bromage, N., 2004: Reproductive response of Nile tilapia (Oreochromis niloticus) to photoperiodic manipulation: effects on spawning periodicity, fecundity and egg size. Aquaculture 231, 299– 314. Chellappa, S.; Câmara, M. R.; Chellappa, N. T.; Beveridge, M. C. M.; Huntingford, F. A., 2003: Reproductive ecology of a neotropical Cichlid fish, Cichla monoculus (Osteichthyes: Cichlidae). Braz. J. Biol. 63, 17– 26. Coward, K.; Bromage, N. R., 1999: Spawning periodicity, fecundity and egg size in laboratory-held stocks of a substrate-spawning tilapiine, Tilapia zillii (Gervais). Aquaculture 171, 251– 267. Duponchelle, F.; Lino, F.; Hubert, N.; Panfili, J.; Renno, J. F.; Baras, E.; Torrico, J. P.; Dugue, R.; Nuñez, J., 2007: Environment-related life-history trait variations of the red-bellied piranha Pygocentrus nattereri in two river basins of the Bolivian Amazon. J. Fish Biol. 71, 1113– 1134. Fawole, O. O.; Arawomo, G. A. O., 2000: Fecundity of Sarotherodon galilaeus (Pisces: Cichlidae) in the Opa reservoir, Ile-Ife, Nigeria. Rev. Biol. Trop. 48, 201– 204. Froese, R., 2006: Cube law, condition factor and weight-length relationships: history, meta-analysis and recommendations. J. Appl. Ichthyol. 22, 241– 253. Gomiero, L. M.; Braga, F. M. S., 2003: Relação peso-comprimento e fator de condição para Cichla cf. ocellaris e Cichla monoculus (Perciformes, Cichlidae) no reservatório de Volta Grande, rio Grande - MG/SP. Acta Sci. Biol. Sci. 25, 79– 86. Gomiero, L. M.; Braga, F. M. S., 2004: Reproduction of species of genus Cichla in a reservoir in Southeastern Brazil. Braz. J. Biol. 64, 613– 624. Kullander, S. O., 2003: Cichlidae (Cichlids). In: Checklist of the freshwater fishes of South and Central America. R. E. Reis, S. O. Kullander, C. J. Ferraris-Jr. (Eds). Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, pp. 605– 654. Latini, A. O.; Petrere, M. J. R., 2004: Reduction of a native fish fauna by alien species: an example from Brazilian freshwater tropical lakes. Fish. Manag. Ecol. 11, 71– 79. Le Cren, E. D., 1951: The length–weight relationship and seasonal cycle in gonad weight and condition in the perch (Perca fluviatilis). J. Anim. Ecol. 20, 201– 219. Magalhães, A. L. B.; Sato, Y.; Rizzo, E.; Ferreira, R. M. A.; Bazzoli, N., 1996: Ciclo reprodutivo do tucunaréCichla ocellaris (Schneider, 1801) na represa de Três Marias, MG. Arq. Bras. Med. Vet. Zoot. 48, 85– 92. Muñoz, H.; Van Damme, P. A.; Duponchelle, F., 2006: Breeding behaviour and distribution of the tucunaréCichla cff. monoculus in a clear water river of the Bolivian Amazon. J. Fish Biol. 69, 1018– 1030. Munthali, S. M.; Ribbink, A. J., 1998: Condition and fecundity of translocated rock-dwelling cichlid fish in Lake Malawi. J. Zool. 244, 347– 355. Novaes, J. L. C.; Carmaschi, E. P.; Winemiller, K. O., 2004: Feeding of Cichla monoculus Spix, 1829 (Teleostei: Cichlidae) during and after reservoir formation in the Tocantins River, Central Brazil. Acta Limnol. Bras. 16, 41– 49. Osure, G. O.; Phelps, R. P., 2006: Evaluation of reproductive performance and early growth of four strains of Nile tilapia (Oreochromis niloticus L.) with different histories of domestication. Aquaculture 253, 485– 494. Parenti, L. R.; Grier, H. J., 2004: Evolution and phylogeny of gonad morphology in bone fishes. Integr. Comp. Biol. 44, 333– 348. Pearse, A. G. E., 1985: Histochemistry: theoretical and applied, Vol. 2. Churchill Livingstone, Edinburgh, London, Melbourne and New York, 599 pp. Peña-Mendoza, B.; Gómez-Márquez, J. L.; Salgado-Ugarte, I. H.; Ramírez-Noguera, D., 2005: Reproductive biology of Oreochromis niloticus (Perciformes: Cichlidae) at Emiliano Zapata dam, Morelos, México. Rev. Biol. Trop. 53, 515– 522. Pravia, M. A.; Garcia, C.; Ares, L.; Berois, N., 1995: Estimación de la fecundidad y determinación del tipo de desova de la corvina blanca, Micropogonias furnieri (Teleostei: Sciaenidae). Rev. Bras. Biol. 55, 13– 25. Quintarelli, G.; Tsuiky, S.; Hashimoto, Y.; Pigman, W., 1961: Studies of sialic acid containing mucins in bovine submaxilar and rat sublingual glands. J. Histochem. Cytochem. 9, 176– 183. Ravetto, C., 1964: Alcian blue–Alcian yellow: a new method for identification of different acid groups. J. Histochem. Cytochem. 12, 441. Rizzo, E.; Godinho, H. P., 2003: Superfície de ovos de peixes Characiformes e Siluriformes. In: Águas, peixe e pesca no São Francisco das Minas Gerais. H. P. Godinho and A. L. Godinho (Eds). Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil, pp. 115– 132. Rizzo, E.; Sato, Y.; Barreto, B. P.; Godinho, H. P., 2002: Adhesiveness and surface patterns of eggs in neotropical freshwater teleosts. J. Fish Biol. 61, 615– 632. Santos, J. E.; Padilha, G. E. V.; Bomcompagni-Júnior, O.; Santos, G. B.; Rizzo, E.; Bazzoli, N., 2006: Ovarian follicle growth in the catfish Iheringichthys labrosus (Siluriformes: Pimelodidae). Tissue Cell 38, 303– 310. Sato, Y.; Sampaio, E. V., 2005: A ictiofauna na região do Alto São Francisco, com ênfase no reservatório de Três Marias, Minas Gerais. In: Ecologia de reservatórios: impactos potenciais, ações de manejo e sistemas em cascata. M. G. Nogueira, R. Henry and A. Jorcin (Eds). Rima, São Carlos, São Paulo, Brazil, pp. 251– 274. Sato, Y.; Fenerich-Verani, N.; Nuñer, A. P. O.; Godinho, H. P.; Verani, J. R., 2003: Padrões reprodutivos de peixes da bacia do São Francisco. In: Águas, peixe e pesca no São Francisco das Minas Gerais. H. P. Godinho and A. L. Godinho (Eds). Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil, pp. 229– 274. Simpson, A. C., 1951: The fecundity of the plaice. Fish. Invest. 17, 1– 27. Suzuki, H. I.; Agostinho, A. A.; Winemiller, K. O., 2000: Relationship between oocyte morphology and reproductive strategy in loricariid catfishes of the Paraná River, Brazil. J. Fish Biol. 57, 791– 807. Tesch, F. W., 1971: Age and growth. In: Methods for assessment of fish production in fresh waters. W. E. Ricker (Ed.). Blackwell Scientific Publications, Oxford, pp. 98– 130. Tyler, C. R.; Sumpter, J. P., 1996: Oocyte growth and development in teleosts. Rev. Fish Biol. Fish. 6, 287– 318. Vazzoler, A. E. A. M., 1996: Biologia da reprodução de peixes teleósteos: teoria e prática. Editora da Universidade Estadual de Maringá, Paraná, Brazil, 169 pp. Winemiller, K. O.; Taphorn, D. C.; Barbarino-Duque, A., 1997: Ecology of Cichla (Cichlidae) in two blackwater rivers of Southern Venezuela. Copeia 4, 690– 696. Zaret, M. T., 1980: Life history and growth relationships of Cichla ocellaris, a predatory South American cichlid. Biotropica 12, 144– 157. Zaret, T. M.; Paine, R. T., 1973: Species introduction in a tropical lake. Science 182, 449– 455. Citing Literature Volume25, Issue3Special Issue: Special Issue: Modern Fisheries Research Approaches in BrazilJune 2009Pages 299-305 ReferencesRelatedInformation

Most fishes with commercial importance from the São Francisco basin are migratory and do not complete the reproductive cycle in lentic environments, such as hydroelectric plant reservoirs, hence natural stocks are declining and there is an urgent need to reduce the pressure of fishing on those wild populations. Therefore, studies on reproductive biology and its relationship with endocrine and environmental factors are key to improving the cultivation techniques of Brazilian fish species. This study examined the influence of water temperature on sex steroid concentrations (testosterone, 17β-estradiol and 17α-hydroxyprogesterone), spawning efficiency, fecundity, fertilisation rate, larval abnormality rates and involvement of the cytoskeleton during the final oocyte maturation of Prochilodus argenteus under experimental conditions. The results of our study showed that in captivity, sex steroid plasma concentrations and spawning performance of P. argenteus were clearly different for fish kept in water with different temperature regimes. In lower water temperature (23°C), it was observed that: 33% of females did not ovulate, fecundity was lower and vitellogenic oocytes after the spawning induction procedure exhibited a smaller diameter. Moreover, concentrations of 17β-estradiol and 17α-hydroxyprogesterone were lower and there was a delay in the final oocyte maturation and, consequently, ovulation and spawning. Our experiments showed direct influence of water temperature in the process of induced spawning of P. argenteus. Changes in water temperature also suggest the tubulin involvement in the nuclear dislocation process and the possible action of actin filaments in the release of polar bodies during final oocyte maturation of P. argenteus.

Brycon orthotaenia is an important fish for commercial and sport fishing and may reach 7 kg in body weight; it is endangered in some regions of Brazil's São Francisco River Basin. Breeders were subjected to spawning induction to analyse the early development; oocytes and semen were obtained by manual extrusion and fertilization was carried out using the dry method. After fertilization, eggs were kept in incubators at 24°C. Egg samples were collected every 10 min until hatching in order to monitor embryonic development and were analysed and photographed. Larvae samples were collected daily until the seventh day to analyse the larvae development; larvae were fixed in Bouin's fluid and subjected to routine histological and histochemical techniques for glycoprotein and glyco-conjugated detection. Oocyte extrusion occurred 6 h after the second hormone dose at 26°C. The recently extruded oocytes were spherical, dark green and non-adhesive, with a diameter of 1479.67 ± 53.18 and 3094.60 ± 80.34 μm after hydration. The blastopore closure occurred within 7 h 30 min of fertilization and the fertilization rate was 50.0 ± 5.5 % at 24°C. Embryonic development was completed within 21 h 30 min of fertilization. Complete yolk sac resorption and mouth opening occurred on the third day after hatching, at which time an adhesive organ with mucosubstances was observed. On the third day, an olfactory chamber with cilia and intense cannibalism amongst the larvae was observed. The complete differentiation of the digestive system occurred on the fifth day and the nervous and sensorial systems differentiation occurred on the sixth to seventh days.

The balance between cell proliferation and apoptosis is crucial for tissue development and homeostasis. The present study investigated the contribution of proliferating cell nuclear antigen (PCNA) and apoptosis during ovarian remodeling after spawning in the Nile tilapia Oreochromis niloticus. Breeding females were kept in controlled conditions and ovary samples were collected weekly for TUNEL assay, immunohistochemistry for PCNA and caspase-3 and morphometric analysis. During the follicular growth, PCNA labeled mainly the nuclei of oocytes and follicular cells in a high proportion of follicles especially in primary growth, while a low occurrence of apoptosis in follicular and theca cells was detected. At 0–3 days post-spawning, post-ovulatory follicles showed no proliferative activity, however the follicular cells exhibited high rates of apoptosis. At 7–10 days, PCNA labeled the thecal cells in a low proportion of post-ovulatory follicles, which showed follicular cells with lower rates of apoptosis. PCNA labeled mainly the theca in the advanced and late stages of atretic follicles, while the follicular cells exhibited a significant increase of apoptosis along follicular atresia. We concluded that PCNA and apoptosis work cooperatively to ensuring the success of follicle development and maintaining of tissue homeostasis during follicular growth. PCNA and apoptosis are also essential mechanisms in the follicular regression during post-spawning ovarian recovery in the Nile tilapia.

Field studies evaluating the effects of endocrine disruption chemicals (EDCs) on the fish reproduction are scarce worldwide. The goal of this study was to assess hepatic levels of vitellogenin (Vtg), zona radiata proteins (Zrp) and insulin-like growth factors (IGF-I and IGF-II), and relating them to reproductive endpoints in a wild fish population habiting a reservoir that receive domestic sewage, agricultural and industrial residues. Adult fish Astyanax fasciatus were sampled during the reproductive season in five sites from the Furnas Reservoir, Grande River, and Paraguay–Paraná basin. As a control to field data, fish were experimentally exposed via dietary intake, to oestradiol benzoate (OB) for 7 days. Fish from site with little anthropogenic interference showed hepatic levels of Vtg, Zrp and IGF-I and IGF-II similar to those from the non-treated experimental group. In sites located immediately downstream from the municipal wastewater discharges, the water total oestrogen was >120 ng/l, and male fish displayed increased Vtg and Zrp and decreased IGF-I levels similar to OB treated fish. In females, levels of Vtg, Zrp, IGF-I and IGF-II suggest an impairment of final oocyte maturation and spawning, as also detected by frequency of over-ripening, follicular atresia and fecundity. At the sites that receive agricultural and industrial residues, the water total oestrogen was <50 ng/l and females showed decreased Zrp and increased IGF-II levels associated to reduced diameter of vitellogenic follicles, indicating an inhibition of oocyte growth. Overall, the current study reports oestrogenic contamination impairing the reproduction of a wild fish from a hydroeletric reservoir and, the data contribute to improving the current knowledge on relationship between hepatic Vtg, Zrp and IGF-I and IGF-II, and reproductive endpoints in a teleost fish. In addition, our data point out novel reproductive biomarkers (IGF-I, IGF-II and over-ripening) to assessing xenoestrogenic contamination in freshwater ecosystems.

In fish ovaries, postovulatory follicles (POFs) are key biomarkers of breeding and provide an interesting model for studying the relationship between autophagy and apoptosis. In this study, we investigated the immunohistochemical expression of autophagic and apoptotic proteins to improve the knowledge on the mechanisms regulating ovarian remodeling after spawning. Females from three neotropical fish species kept in captivity were submitted to hormonal induction. After ova stripping, ovarian sections were sampled daily until 5 days postspawning (dps). Similar events of POF regression were detected by histology, terminal transferase-mediated dUTP nick-end labeling (TUNEL), and electron microscopy in the three species: follicular cells hypertrophy, progressive disintegration of the basement membrane, gradual closing of the follicular lumen, theca thickening, and formation of large autophagic vacuoles preceding apoptosis of the follicular cells. Autophagic and apoptotic proteins were assessed by immunohistochemistry. Morphometric analysis of the immunolabeling revealed a more intense reaction for bcl-2 and beclin-1 (BECN1) in POFs at 0 to 1 dps and for bax at 2 to 3 dps (P < 0.001), the later period being the peak of apoptosis of the follicular cells. The immunostaining for cathepsin-D was more elevated until 2 to 3 dps and decreased significantly at 4 to 5 dps, when the POFs were in late stage of regression. Double labeling for BECN1 and caspase-3 indicated a shift in the relationship between autophagy and apoptosis at 2 to 3 dps, a critical period in determining the fate of follicular cells in POFs. Together, these results indicate that the bcl-2 family, BECN1, and cathepsin-D can be involved in the regulation of ovarian remodeling in teleost fish.

The morphofunctional organisation of the female reproductive system, the oocyte growth and the follicular envelope ultrastructure were studied by the first time in the catfish Iheringichthys labrosus from Upper Paraná River basin, Southeastern Brazil, in order to contribute to the knowledge of the reproductive behaviour strategies of this species. As in other Neotropical freshwater siluriforms, the ovaries are of the cystovarian type, the oocytes develop in an asynchronous pattern and mature oocytes are released in clusters in the ovarian lumen, being transported through the oviduct to the urogenital papilla. During the primary growth, nuclear material is transported to the ooplasm, forming the yolk nucleus, where proliferate membranous organelles. The onset of the zona radiata formation occurs during the late perionucleolar stage with the deposition of the outer layer. At the vitellogenic stage, this envelope reaches 6.35 ± 0.84 μm of thickness, being constituted by three distinct layers crossed by pore-canals containing oocyte and follicular cells processes. Cytochemical analyses evidence neutral glycoproteins in cortical alveoli, yolk globules and zona radiata. Follicular cells with squamous shape during the primary growth acquire synthetic activity at the secondary growth, reaching 37.82 ± 4.72 μm in height at the mature vitellogenic follicles. These cells accumulate sulphated polysaccharides in large electron-lucent vesicles during the vitellogenic stage which are possibly secreted to form a mucous coat at the egg surface. These evidences suggest that I. labrosus may have adhesive eggs as also detected in other Neotropical freshwater Siluriformes.

Generally, migratory fish can complete vitellogenesis even when the migration process is interrupted; however, final oocyte maturation does not occur and therefore there is no spawning. To evaluate the reproductive process of migratory fish inside the reservoir of the Três Marias Dam (a lentic environment), 90 female and 81 male Prochilodus argenteus and 172 female and 115 male Prochilodus costatus were captured in this environment. Males and females from both species in the resting stage were pre-dominant, and the highest frequency of specimens in advanced maturation stages occurred in November, December and January. According to histological analysis, ovarian regression was frequent and vitellogenic oocytes undergoing atresia were intensely observed, moreover, no fish with ovaries and testes with characteristics of spawning and spermiation, respectively, were captured. This indicated that both species were preparing for reproduction and reaching advanced gonad maturation, but were unable to complete the process of reproduction in this environment. The data from this study indicate that the modification of portions of rivers to lentic environments can have a negative impact on the reproductive process of migratory fish in freshwater.

Downstream impacts of dams on fish fauna are poorly studied, despite causing thermal and hydrological changes that affect the reproductive activity of the fish community.The present study aims to evaluate the reproduction of Leporinus reinhardti in 2 sections of the São Francisco River, Brazil, downstream from the Três Marias Dam.Section 1 (S1) is the first 34 km downstream from Três Marias Dam and section 2 (S2) is 34 to 54 km downstream from the dam, where the São Francisco River receives a mid-sized tributary called the Abaeté River.In S1, the values of temperature, dissolved oxygen and flow were lower than those obtained in S2.In S1, females and males did not complete reproduction, a fact proven by the absence of spawned females and males.In S2, reproductive success was proven due to the presence of spawned females and males.Furthermore, the values of total length, body weight, gonadosomatic index, fecundity and vitello genic oocytes were statistically higher than those obtained in S1.The canonical correlation test indicated that the reproduction of females is more dependent on environmental factors than that of males.In S2, L. reinhadti found appropriate conditions for reproduction, probably influenced by the Abaeté River, confirming the need of preserving this tributary for the reproductive success of this species.

The fish gill is in direct and standing contact with the immediate external environment and, therefore, is highly vulnerable to aquatic pollutants. In this study, Prochilodus argenteus were caught at two different points in São Francisco river. The first point is located near Três Marias dam, while the second is placed downstream the Abaeté river. Chemical approaches showed the presence of metals contamination in the first point. Thus, the main goal of this study was to investigate the possible toxic effects of these contaminants and the likely use of biomarkers on fish gills. Biometric data of length and weight of fish were obtained in order to calculate the condition factor as an organismal biomarker. The histological changes in gills and alterations in mucous and rodlet cells occurrence were detected microscopically and evaluated with quantitative analyses. Myeloperoxidase (MPO) and Eosinophil Peroxidase (EPO) were also assessed in fish gill. The analysis of the water and sediment samples revealed the presence of metals at the two points. As and Cd were detected at higher concentrations at point 1. The presence of lamellar cell hyperplasia, lamellar fusion, lamellar edema and inflammatory foci varied according to the point. Additionally, mucous and rodlet cells and MPO and EPO activities showed variability according to the environmental conditions. Furthermore, with exception of lamellar hyperplasia and eosinophil peroxidase activity, all others parameters showed sex-variation responses. At the first point, male fish showed a chronical inflammation in gills due to the lowest activity of MPO and EPO, as well as low occurrence of inflammatory foci and glycoprotein secretion by mucous cells, while female fish presented an opposite pattern of response to the same environmental conditions. Therefore, we suggest the use of such biomarkers in future monitoring of aquatic systems, taking into account the sex-variation responses.

The neotropical characid Salminus franciscanus is an economically valuable migratory fish whose populations have been drastically reduced in recent decades due to industrial and economic development in Brasil. To study its reproduction, a total of 283 adult specimens were captured in the Upper São Francisco River, downstream from the Três Marias dam, Minas Gerais, south-eastern Brasil, from August 2009 to July 2010. The gonadal maturity stages were determined from histological features of the gonads and gonadosomatic index (GSI). Gametogenesis was assessed by light and electron microscopy. For analysis of the oocyte's surface and fecundity, mature females were subjected to hormonal induction and oocyte stripping. Fish in resting (Stage 1) were common in all samplings, ripening/ripe and spawning (Stages 2 and 3) were predominant in October–November and December–January and post-spawning (Stage 4) occurred from December–January extending until April–May. The GSI followed the morphological changes of gonadal maturation, with a peak in October–November, when maximum GSI (7.08 in females and 3.46 in males) was achieved. From scanning electron microscopy, stripped oocytes showed a funnel-shaped micropyle and a simple oocyte surface arrangement, which is typical for non-adhesive eggs. Fecundity ranged from 160 to 440 × 103 oocytes per female and 129 to 175 × 103 oocytes/kg. The results of this study indicate that S. franciscanus reproduces in the Upper São Francisco River from October to January, exhibiting a total spawning pattern, non-adhesive eggs and high fecundity, providing support for aquaculture and conservation biology of this important neotropical characid fish.

Discharge of municipal wastewater promotes the entry of diverse oestrogenic compounds into the water bodies. This complex mixture of substances interferes in the steroidogenic pathway, being able to promote severe reproductive impairment in freshwater fish populations. The purpose of the present study was to evaluate the effects of oestrogenic endocrine disruptors (EDCs) mixture on gonadal sex steroids (testosterone, T; 11-ketotestosterone, 11-KT; 17β-oestradiol, E2; 17-hydroxyprogesterone, 17-OHP) in the peak of the reproductive season of Astyanax rivularis, correlating the results obtained with the proportion of germ cells and gonadal histopathology. Three sampling sites were chosen to conduct the study, one reference site (S1), without contamination by municipal wastewater and two sites (S2 and S3) receiving discharge of municipal wastewater. Males of A. rivularis presented higher concentrations of E2, lower androgens (T and 11-KT) in gonads when compared to males from site S1. Concentrations of 17-OHP did not present significant difference among sites. In sites S2 and S3, the proportion of early spermatocytes, spermatids and Leydig cells increased while spermatozoa decreased compared to fish from S1. The following gonadal histopathologies were detected in the male fishes: intersex gonads (28% in S3) and testicular degeneration with germinal epithelium exhibiting agglutinated germ cells masses and empty cysts (57% in S2 and 71% in S3). In females, concentrations of T, E2 and 17-OHP did not present significant difference among the sites, however higher 11-KT concentrations were detected in females from sites S2 and S3. A lower proportion of perinucleolar follicles and a higher incidence of vitellogenic follicles, besides, aged oocytes and the presence of eosinophilic proteinaceous fluid in the interstitial compartment were also found in females from impacted sites. These results indicate that the urbanization and consequent release of municipal wastewater containing oestrogenic compounds in the headwater creeks are altering the levels of sex hormones and gametogenesis of A. rivularis. Further studies should be performed to determine whether oestrogenic endocrine disrupters are disrupting the reproduction of A. rivularis.

Fish embryos are particularly vulnerable to temperature changes, with the effects varying with developmental stage. The major aim of the present study was to analyse the relationship between apoptosis and heat shock protein (HSP) 70 during embryo development under thermal stress conditions. To this end, Prochilodus lineatus embryos at the blastopore closure stage were subjected to one of three thermal treatments for 1h (Group 1, 25°C (control); Group 2, 20°C; Group 3, 30°C) and then examined at 0, 4 and 8h posttreatment (h.p.t.). The viability of embryos was highest in Group 1 (81.33±16.65%), followed by Group 3 and Group 2 (75.33±12.10% and 68.67±16.86% respectively), with significant difference between Groups 1 and 2 (P&amp;lt;0.05). At 0h.p.t., embryos subjected to thermal stress (Group 3) had a significantly higher number of terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling (TUNEL)- and caspase-3-labelled cells, and a lower number of HSP70-positive cells than those in the control group. At 4h.p.t., there was a decrease in the TUNEL reaction and an increase in HSP70 in embryos in Group 3. At 8h.p.t., the size of Group 3 embryos was significantly smaller than that of Group 1 embryos. The results indicate a cytoprotective role for HSP70, regulating caspase-3-mediated apoptosis during embryo development of P. lineatus; however, this mechanism is not effective in controlling embryo viability and larval malformations.

Abstract Follicular atresia is a hormonally controlled degenerative process involving apoptosis of the somatic and germ cells. Since different signaling pathways can induce cell death, the aim of the present study was to investigate cell death signaling and crosstalk between autophagic, apoptotic, and lysosomal proteins during follicular atresia in Nile tilapia. For this, females were kept in controlled conditions for 21 days, and ovary samples were collected weekly. The atretic follicles (AF) were analyzed in three regression phases: Early, advanced, and late. Under electron microscopy, the follicular cells exhibited numerous protein synthesis organelles in the early AF. Immunoreactivity for Bcl2, Beclin1, Lc3, and Cathepsin D increased significantly in advanced AF ( p &lt; .001), when follicular cells were in intense yolk phagocytosis. In this phase, autophagosomes and autolysosomes were frequently observed. In the late AF, follicular cells had a markedly electron‐lucid cytoplasm and immunoreactivity for Bax and TUNEL assay indicated an elevated apoptosis rate. Colocalisation of Lamp1/Cathepsin D and Lc3/Caspase‐3 suggests dynamic crosstalk between the autophagy, apoptosis, and lysosome pathways. Taken together, the data indicate that autophagy plays a role in the homeostasis and clearance of the follicular cells preceding Cathepsin D mediated apoptosis during follicular atresia in Nile tilapia.

Continental waters salinisation is a global threat that has grown because of climate change and human activities, but little is known about how and what biological tracts are affected. The aim of this study was to investigate the influence of different water salinities on the expression of HSP70, PCNA and caspase-3 during spermatogenesis of Nile tilapia. Adult males were submitted to four salinity treatments: (S0) fresh water, (S7) 7 g L−1, (S14) 14 g L−1, and (S21) 21 g L−1 for 1, 4, and 9 days. All specimens were in spermatogenic activity and the highest values of the gonadosomatic index (GSI) occurred in the S0 and S7. In the morphometric analysis, spermatocytes were the most frequent germ cell detected in all treatments (>50%) and spermatids achieved about 20% of the testicular proportion, with few variations among treatments. Spermatozoa were significantly reduced only in S14 compared to S7. Leydig cells were significantly increased in S14 when compared to S7 but plasma concentrations of 11-KT showed no significant difference among treatments. ELISA assay showed higher testicular expression of HSP70 at 1 day in all groups, followed by a significant decrease at days 4 and 9 in S14 and S21. The expression of PCNA was significantly lower while the activity of caspase-3 was higher in S14 and S21 when compared to S0 and S7. These results indicate that higher salinities in S14 and S21 interfere with the relationship between testicular HSP70, PCNA, and caspase-3, but with few effects over spermatogenesis dynamics of Nile tilapia.

Congeneric species often coexist in sympatry using behavioral and morphological adaptations to reduce competition and interspecific interference, but reproductive patterns behind coexistence remain unknown. We analyzed the gonadal morphology and development, reproductive cycle, and population structure of two sympatric congeneric fishes to evaluate the degree of overlap and differentiation of the reproductive biology between species in a Neotropical river. Development of testes and ovaries were similar between species, both showing asynchronous gonadal development, large diameter of gametes and synthesis of mucosubstances by follicle cells to form adhesive eggs. Although the morphometry of germ cells did not present differences, the zona radiata of mature eggs in Hypostomus garmani was markedly thicker than H. francisci, which suggests different spawning habitats. Both species have greater reproductive activity in the rainy season, concomitant with increase in water temperature, however H. garmani initiates and ends its reproduction earlier than H. francisci, indicating a differentiation of reproductive periods. Sexually mature males and females of H. francisci reproduced at a larger mean size then H. garmani. The two congeneric species had a similar abundance and sex ratios in the study area. Results show that although the species exhibited broad overlap of reproductive traits, a spatial and temporal differentiation of the reproductive biology was present. This study contributes to understanding reproductive mechanisms that may facilitate coexistence between congeneric sympatric species.

Estrone (E1) is a common environmental contaminant found in rivers and streams due to the farming of animals, such as swine and cattle. Our study evaluated the effects of chronic E1 exposure at environmentally relevant concentrations on spermatogenesis and the semen quality of zebrafish (Danio rerio). We exposed the fish to E1 at concentrations of 20, 200, and 2000 ng/L diluted in 0.001% ethanol (v/v) for 49 days. There were two control groups: one was exposed to water only and the other to ethanol at the same concentration used in the E1 groups. Following exposure, we analyzed the proportion of testicular cell types and other components (%), rate of cell proliferation and death, and sex steroid concentrations. Furthermore, we analyzed the expression of insulin-like growth factor 1 (IGF1), IGF2, IGF1 receptor (IGF1R), and inducible nitric oxide synthase and assessed the semen quality. E1 exposure increased spermatogonia, spermatids, Sertoli cells, Leydig cells, and the proportion of inflammatory infiltrate but decreased the spermatozoa amount. These changes were reflected by reductions in the gonadosomatic index and levels of 11-ketotestosterone in the testes. On the other hand, E1 exposure increased testicular estradiol, IGF1R expression, and nitric oxide production. After an evaluation using a computer-assisted sperm analysis (CASA) system, we observed reduced progressive motility, curvilinear velocity, and beat cross frequency of 20 and 2000 ng/L E1 groups. Our findings support that E1 causes deleterious effects on the testicular function and semen quality of D. rerio even at environmental concentrations. Thus, E1 concentrations should be monitored in surface waters for the purposes of fish conservation.

The most recent dam rupture in Brazil released tons of mining tailings into the upper course of the Paraopeba River, affecting this river in an unprecedented way. The present study aimed to evaluate the influence of heavy metals on Prochilodus costatus, an important commercial species in Brazil, four years after the dam colapse. To this end, biomarkers of heavy metals, oxidative stress, and environmental stress were analyzed, and histological analyses of target organs were performed. The results demonstrated critical contamination of fish from the Paraopeba River. Increased expression of Metallothioneins - MTs, Heat Shock Protein - HSP70, and inducible nitric oxide synthase - iNOS, as well as greater rates of histological changes in the liver, spleen, and gonads, were observed in P. costatus. These findings demonstrate that, despite past contamination, the metals present in mining tailings have significantly increased the contamination of the Paraopeba River basin.

The reproductive biology of the piau-jejo Leporinus taeniatus Lütken, 1875, an endemic species from the São Francisco River basin, was studied by using macroscopical and histological techniques. A total of 121 males and 94 females were captured quarterly, between March 2002 and February 2003 in the Juramento Reservoir. Females were larger than males, indicating sexual dimorphism. Stages of gonadal maturation were defined from histological analyses and gonadosomatic index. Peaks of maturing/mature and spawned/spermiated fishes has occurred in period December-February. L. taeniatus presented total spawning and group-synchronic development of the oocytes. The gonadosomatic index accompanied gonad maturation in both sexes, and coelomic fat presented lower levels during maturing/mature stage, indicating fat consumption during the reproductive period. Stomach repletion index presented higher values during spawned and spermiated stages, indicating greater food ingestion after the reproductive period.

Abstract Martins, Y.S., Arantes, F.P., Sato, Y., dos Santos, J.E., Rizzo, E. and Bazzoli, N. 2012. Comparative analysis of gonadal morphology in six fish species of the Incertae Sedis genera in Characidae of occurrence in the São Francisco River Basin, Brazil. — Acta Zoologica (Stockholm) 93 : 48–56. This study presents a comparative analysis aiming to show the remarkable differences found in gonad morphology between six fish species from the genera Incertae Sedis in the Characidae family. Maturing ovaries of Astyanax fasciatus presented grayish color whilst the other species’ were yellowish in color. The cortical alveoli of the analyzed species are small (5.20 ± 1.44–8.28 ± 2.02 μm) and are formed by various discontinuous layers of vesicles except in the Bryconops affinis , where they are large (12.87 ± 2.41 μm) and form various continuous layers of vesicles. The pellucid zone is thin and varies from 2.44 ± 0.90 to 5.79 ± 1.90 μm and is thickest in B. affinis (10.57 ± 2.08 μm). Folds in the pellucid zone were observed in Astyanax bimaculatus , A. fasciatus , Hemigrammus marginatus , and Moenkhausia costae. The follicular cells of B. affinis are columnar (28.19 ± 13.71 μm), while they are squamous in other species (1.52 ± 0.64–2.12 ± 0.78 μm). This study showed that the morphologic and biometric characteristics of the B. affinis vitellogenic oocytes are statistically different than the analyzed other ones Incertae Sedis of the Characidae family. In advanced maturing testis of A. bimaculatus and A. fasciatus , the spermatozoa were embedded in acidophilic secretion which was gradually reabsorbed in the seminiferous tubules when males were partially spent.

ABSTRACT This study investigated the relationship among heat shock protein 70 (HSP70), proliferating cell nuclear antigen (PCNA), and testicular apoptosis during a breeding cycle of Prochilodus argenteus , a neotropical migratory characiform fish of importance in commercial fishery from the São Francisco River basin. A total of 48 (12 fish/sampling) adult males were caught using casting and drifting nets in four samplings from June 2008 to March 2009. Immunohistochemistry, Western blotting, terminal transferase‐mediated dUTP nick‐end labeling (TUNEL), enzyme‐linked immunosorbent assay (ELISA), and caspase‐3 colorimetric assay were assessed in different phases of spermatogenesis. Labeling for HSP70 occurred in spermatogonia (SPG A 18.0±1.5 and SPG B 27.9±1.0 in 100 mm 2 , respectively) and Sertoli cells in all sampling periods, with higher values in June (resting period) while spermatocytes were labeled in September (maturation period) and December (ripe period). For PCNA, immunoreaction was predominant in spermatogonia in June and September, while primary spermatocytes were labeled mainly in December (18.7±2.0). TUNEL‐positive reaction occurred throughout the sampling periods, and labeling was detected in the nucleus of germ cells in all developmental phases, except spermatozoa. By ELISA, total HSP70 in testis increased significantly from June to December, and decreased in March (regression period), P &lt;0.05. Caspase‐3 activity decreased from June to December and increased in March. Taken together, our results suggest that HSP70 may protect the germ cells from caspase‐3‐dependent apoptosis during testicular activity and, reduction of HSP70 and increase of apoptosis contribute for testicular remodeling after the breeding season in wild populations of P. argenteus in the São Francisco River. Microsc. Res. Tech. 76:350–356, 2013 . © 2013 Wiley Periodicals, Inc.

Summary This study shows for the first time the presence of a jelly coat on oocytes of neotropical Characiformes fish. This structure could be responsible for the adhesiveness of Astyanax bimaculatus oocytes, a species widely distributed in South America including in the São Francisco River basin in Brazil. Adult specimens of A. bimaculatus were submitted to artificial reproduction in order to analyse the egg morphology and embryonic development. The eggs were fertilised and kept in incubators with a water temperature of 24°C so that embryogenesis could be monitored. Ovulated and unfertilised oocytes were also collected and submitted to routine histological techniques. Astyanax bimaculatus oocytes were found to be spherical, yellowish, and covered by a thin jelly coat with a slightly adhesive surface. The mean oocyte diameter was 1.03 ± 0.03 mm, the perivitelline space was 0.21 ± 0.02 mm and the jelly coat's thickness was 0.04 ± 0.01 mm. Positive periodic acid–Schiff (PAS) stain and Alcian blue stain pH 2.5 indicated the presence of neutral glycoproteins, and carboxylated acid glycoconjugates on the jelly coat that formed mucosubstances that may be associated with egg adhesiveness. At a water temperature of 24°C, blastopore closure and hatching occurred at 5 h and 17 h after fertilisation, respectively. The results of this study provide essential information for phylogenetic studies and for a better understanding of the reproductive strategy of A. bimaculatus , currently included in the incertae sedis group of the Characidae family due to the lack of monophyly among the families of the group.

Understanding the influence of different temperature conditions on the spermatogenesis is important for improvement of the fish aquaculture. This study evaluated the influence of low temperature on structural and quantitative dynamics of the spermatogenesis in Oreochromis niloticus. Adult males were cultivated with room temperature water (20.28-22.46°C) and testes were collected for histological, ultrastructural and morphometric analyses. This species has unrestricted lobular testis with cystic spermatogenesis and type I spermiogenesis that results in a single anacrosomal aquasperm. Seminiferous lobules and spermatogenic cells had a radial arrangement toward the spermatic duct. Superior and central portions of testes had a greater lobular area than the inferior portion in all samplings. Spermatogonia (9.3%) were distributed in the inferior portion of testes, spermatocytes (25.3%) and spermatids (34.4%) in the central portion, while spermatozoids (39.4%) and secretory cells (4.6%) in the superior portion. Throughout the study, correlation between water temperature and lobular area characteristics was significant only in the inferior portion of testes (r(2)=0.95), although the lobular area in the other testicular portions increased when the water temperature increased by 2°C. Correlation between the water temperature and spermatogenic cells was significant for undifferentiated spermatogonia (r(2)=0.54) and number of spermatids (r(2)=0.67). It is concluded that low cultivation temperatures may positively influence the generation of primary spermatogonia in the inferior periphery of O. niloticus testes. In addition, males maintain reservoirs of germ cells at low temperatures and the radial zonation of spermatogenesis has an important role in the renewal and production of germ cells.

To support sperm production, fish testes undergo intense tissue remodelling, with endocrine, paracrine and autocrine signals regulating gonad physiology. The aim of this study was to investigate the testicular expression of insulin-like growth factor (Igf) 1 and Igf2 during spermatogenesis, and their relationship with cell proliferation and apoptosis throughout the reproductive cycle. The study was performed in male Hypostomus garmani, a catfish living in headwater rivers of the São Francisco River basin, Brazil. Spermatogenesis was analysed using histology, morphometry, immunohistochemistry and terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling (TUNEL) analysis at different maturity stages. The results showed the proliferation of spermatogonia throughout the reproductive cycle, with a higher rate during the ripe stage. Germ and Sertoli cells expressed Igf1 at all stages of testicular maturity, Igf2 was predominant at the ripe stage and both Igf1 and Igf2 occurred at the spent stage. Caspase-3 and TUNEL analysis revealed a higher rate of apoptosis at the spent stage associated with reduced expression of Igf1 and Igf2. Sertoli cell proliferation was associated with spermatogonia and spermatocyte cysts at different stages of the reproductive cycle. Together, the data support a proliferative role for Igf1 and Igf2 in regulating testicular apoptosis in H. garmani, with cyclical variation in their expression during gonad maturation.

Spermatogenesis is a finely regulated process that involves the interaction of several cellular mechanisms to ensure the proper development and maturation of germ cells. This study assessed autophagy contribution and its relation to apoptosis in fish spermatogenesis during starvation. To that end, Nile tilapia males were subjected to 0 (control), 7, 14, 21, and 28 days of starvation to induce autophagy. Testes samples were obtained for analyses of spermatogenesis by histology, electron microscopy, immunohistochemistry, and western blotting. Sperm quality was assessed using a computer-assisted sperm analysis (CASA) system. Data indicated a significant reduction in gonadosomatic index, seminiferous tubule area, and spermatozoa proportion in fish subject to starvation compared to the control group. Immunoblotting revealed a reduction of Bcl2 and Beclin 1 associated with increased Bax and Caspase-3, mainly after 21 and 28 days of starvation. LC3 and P62 indicated reduced autophagic flux in these starvation times. Immunolabeling for autophagic and apoptotic proteins occurred in all development stages of the germ cells, but protein expression varied throughout starvation. Beclin 1 and Cathepsin D decreased while Bax and Caspase-3 increased in spermatocytes, spermatids, and spermatozoa after 21 and 28 days. Autophagic and lysosomal proteins colocalization indicated the fusion of autophagosomes with lysosomes and lysosomal degradation in spermatogenic cells. The CASA system indicated reduced sperm motility and velocity in animals subjected to 21 and 28 days of starvation. Altogether, the data support autophagy acting at different spermatogenesis stages in Nile tilapia, with decreased autophagy and increased apoptosis after 21 and 28 days of starvation, which results in a decrease in the spermatozoa number and sperm quality.

The reproductive biology of Iheringichthys labrosus (Lütken, 1874) was studied in Furnas reservoir, Minas Gerais, Brazil. The fishes, 323 males and 817 females, were captured bimonthly from August 1993 to July 1994 by using gill nets with 3-10 cm mesh size. Gonadal maturation of the specimens was analyzed through macro and microscopical characteristics of the gonads. The secretory activity of the tubules of the caudal region of the testis was analyzed during the maturational testicular cycle. Females and males were in reproductive activity throughout the year in the reservoir. The peak of advanced maturation/mature stages occurred from October to January and of spawned/spent from February to May. The spawning of I. labrosus was identified as fractional or multiple type: occurring in the reservoir or in tributaries around it. The oocyte development of the species was asynchronous as different clusters of oocytes occurred simultaneously in the ovarian parenchyma. The epithelium of the tubules of the caudal region of the testis was in high secretory activity during advanced maturation/mature stage and this activity was absence in resting. The gonadosomatic index followed gonadal maturation, and the hepatosomatic index of females was lowest in advanced maturation/mature probably due the contribution of the liver in the vitellogenesis. The variations of the stomach repletion index, coelomic fat and condition factor indicated that the feeding activity was reduced and that the energetic reserves were consumed during the reproductive period.

Semicystic, a rare type of spermatogenesis, was detected in the characid Hemigrammus marginatus and characterized by cysts hatching during the spermatid phase and maturation of the spermatozoa being completed at the lumen of the anastomosed seminiferous tubules. Primary spermatogonia, or type A, are distributed along the entire length of the seminiferous tubules, in an unrestricted spermatogonial pattern. H. marginatus spermiogenesis is included in type I, mainly characterized by presence of nucleus rotation. During this process, a vesicle resembling the acrosomal vesicle is visualized at the anterior region close to the nucleus of the early spermatids, however this structure did not remain in the spermatozoa. In H. marginatus, the spermatozoon is uniflagellated, primitive, type I aquasperm, with a rounded head, a short midpiece and a long flagellum with the axoneme in a 9 + 2 microtubules arrangement and no lateral fins. Residual spermatozoa are reabsorbed by Sertoli cells. Unusual biflagellate spermatozoa with three long cytoplasmatic projections originating in the midpiece are rarely observed and have not been registered in other characiforms. Ultrastructural characteristics of the spermatogenesis and spermatozoa observed in the present work provide important subsidies to systematic and phylogeny studies of Characidae fishes included in Incertae sedis groups, such as H. marginatus.

Abstract Martins, Y.S., Moura, D.F., Santos, G.B., Rizzo, E. and Bazzoli, N. 2009. Comparative folliculogenesis and spermatogenesis of four teleost fish from a Reservoir in south‐eastern Brazil. — Acta Zoologica (Stockholm). 91 : 466–473. This study provides a comparative analysis of gametogenesis of neotropical teleosts Metynnis maculatus , Megalancistrus parananus , Cichla kelberi and Satanoperca pappaterra , through histological, histochemical and histometric techniques. In the ooplasm of C. kelberi and S. pappaterra conspicuous lipid vesicles were observed, which are characteristic of pelagic eggs produced by marine fishes. Perinucleolar oocytes were identified in the testis of S. pappaterra suggesting that this species is protogynous without functional hermaphroditism, an unusual pattern for neotropical fresh‐water fishes. The spermatozoa of the studied species have rounded heads, a characteristic of fish that externally fertilise their eggs. The follicular (granulosa) cells of the vitellogenic oocytes from the studied species were cuboidal or columnar, however, in C. kelberi there were columnar follicular cells at the vegetal pole and cuboidal cells at the animal pole. Variations of the histochemical content were detected in the cortical alveoli and follicular cells of vitellogenic oocytes showing differences in the mechanisms to block polyspermy and egg adhesiveness. Larger oocytes were recorded in species which demonstrated parental care behaviour and smaller oocytes were noted in those species with fractioned spawning.

Thiodan® is an organochlorine insecticide used in agriculture that can reach aquatic ecosystems where it can affect fish reproduction. This research aimed to evaluate follicular development and the expression of integrin β1, collagen type IV and caspase 3 by morphological, histometrical and immunohistochemical analyses of Astyanax bimaculatus exposed to Thiodan®. Treatments included three sublethal concentrations of Thiodan® (1.15, 2.30, and 5.60 μg L−1) for 96 h and a control without the insecticide. Mature females with ovaries in advanced follicular development were chosen for study (average weight: 11.52 ± 2.0 g; average total length: 9.12 ± 0.64 cm). The follicles of A. bimaculatus exhibited normal morphology, while the diameters of secondary follicles showed an increase (P< 0.05) in all concentrations when compared to the control group; a characteristic of follicles undergoing the initial stages of intoxication. Immunohistochemical analysis revealed secondary follicles with greater expression of integrin β1 and collagen type IV in cytoplasm of follicular cells than in the primary follicles in all treatments and in the control. Immunolocalization of caspase 3 was detected in follicular cells during secondary development in all tested concentrations of Thiodan® and the control. These analyses demonstrate positive immunolocalization throughout the course of follicular development, even in fish exposed to varying concentrations of Thiodan® for 96 h, demonstrating that follicular cells retain their physiological integrity.

Journal of Applied IchthyologyVolume 27, Issue 6 p. 1332-1336 Comparative oocyte morphology and fecundity of five characid species from São Francisco River basin, Brazil R. M. C. Melo, R. M. C. Melo Programa de Pós-graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, PUC Minas, Belo Horizonte, MG, BrasilSearch for more papers by this authorC. M. Ferreira, C. M. Ferreira Programa de Pós-graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, PUC Minas, Belo Horizonte, MG, BrasilSearch for more papers by this authorR. K. Luz, R. K. Luz Labortatório de Aquacultura, Escola de Veterinária da Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrasilSearch for more papers by this authorY. Sato, Y. Sato Estação de Hidrobiologia e Piscicultura de Três Marias, CODEVASF, Três Marias, MG, BrasilSearch for more papers by this authorE. Rizzo, E. Rizzo Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrasilSearch for more papers by this authorN. Bazzoli, N. Bazzoli Programa de Pós-graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, PUC Minas, Belo Horizonte, MG, BrasilSearch for more papers by this author R. M. C. Melo, R. M. C. Melo Programa de Pós-graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, PUC Minas, Belo Horizonte, MG, BrasilSearch for more papers by this authorC. M. Ferreira, C. M. Ferreira Programa de Pós-graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, PUC Minas, Belo Horizonte, MG, BrasilSearch for more papers by this authorR. K. Luz, R. K. Luz Labortatório de Aquacultura, Escola de Veterinária da Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrasilSearch for more papers by this authorY. Sato, Y. Sato Estação de Hidrobiologia e Piscicultura de Três Marias, CODEVASF, Três Marias, MG, BrasilSearch for more papers by this authorE. Rizzo, E. Rizzo Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, BrasilSearch for more papers by this authorN. Bazzoli, N. Bazzoli Programa de Pós-graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, PUC Minas, Belo Horizonte, MG, BrasilSearch for more papers by this author First published: 20 September 2011 https://doi.org/10.1111/j.1439-0426.2011.01876.xCitations: 11 Author's address: Prof Dr Nilo Bazzoli, Programa de Pós-graduação em Zoologia de Vertebrados, PUC Minas, Av. Dom José Gaspar, 500, 30535-901, Belo Horizonte, MG, Brasil.E-mail: bazzoli@pucminas.br Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Summary The morphology of vitellogenic oocytes and the batch fecundity of five tropical forage species belonging to the family Characidae, were studied in 104 late-maturing ovaries. Significant morphological differences between vitellogenic oocytes and ovarian follicles were found. The lowest batch fecundity values were recorded in Hemigrammus marginatus (480 ± 163) and Orthospinus franciscensis (1701 ± 562), which were the smaller species in terms of total length, body weight and oocyte diameter. The highest batch fecundity value was observed in Tetragonopterus chalceus (8384 ± 3944) having the highest GSI and oocyte diameter. Batch fecundity and gonad weight was highly correlated followed by body weight and total length. Relative fecundity was estimated per unit total length, body weight and gonad weight. The wide variation in fecundity observed between the specimens and the species analysed is possibly related to the multiple spawning reproductive strategy of these fishes. Since T. chalceus have higher values of batch and relative fecundity, it is concluded that this species has a higher reproductive potential than the other forage species studied. Citing Literature Volume27, Issue6December 2011Pages 1332-1336 RelatedInformation

Summary The aim of this study was to evaluate the oocytes, post-fertilization events and embryonic development in Brycon insignis , under both scanning electron microscopy and stereomicroscopy. Oocytes and embryos were sampled from spawning up to hatching. Stripped oocytes were spherical, non-adhesive, greenish-brown, possessed a single micropyle, pore-canals and had a mean diameter of 1.46 mm. In 63% of oocytes the germinal vesicle was peripheric. The main post-fertilization events were the fertilization cone formation (20 s), micropyle closure (100–180 s) and agglutination of supernumerary spermatozoa (100–180 s). Embryonic development lasted 30 h at ~24 °C and was characterized by seven stages. Zygote, cleavage, blastula and gastrula stages were first observed at 0.25, 1, 3 and 6 h post-fertilization, respectively. Fertilization rate was determined at the moment of blastopore closure, 10–11 h post-fertilization. The segmentation stage began at 11 h post-fertilization and comprised the development of somites, notochord, optic, otic and Kupffer's vesicles, neural tube, primitive intestine, and development and release of the tail. The larval stage began 21 h post-fertilization and was characterized by the presence of somites, growth and elongation of the larvae. At the hatching stage, embryos presented vigorous contractions of the tail and body leading to chorion rupture (30 h). The morphological characteristics described for B. insignis were similar to that described for other teleost species, and such knowledge is important for a better understanding of reproductive features of a species and useful for ecological and conservational studies.

Cell proliferation and apoptosis regulate germ cells stock and sperm production, eliminate anomalous gametes, and are essential parameters to consider in fish farming. Herein, spermatogenic activity as well as germ cell proliferation and apoptosis were assessed in Leporinus taeniatus, a seasonal breeding species from the São Francisco River basin, Brazil. Testes of 24 adult fishes from a farming station were sampled between December and July and processed for light and transmission electron microscopy and immunohistochemistry for PCNA and TUNEL assay. The gonadosomatic index and seminiferous tubule diameters presented higher values during the breeding season (December/January and February/March), and then significantly reduced during the regression and resting stages (April/May and June/July). Phagocytosis of spermatozoa by Sertoli cells was evident during gonadal regression, but a significant number (up to 30%) remained at the tubular lumen during the resting stage. A higher PCNA/TUNEL ratio occurred in the breeding period, leading to an elevated proportion (%) of spermatogonia (GA and GB) in resting. Moreover, a higher TUNEL/PCNA ratio indicates the contribution of apoptosis to the reduction of germ cells during testicular regression. Together, these results indicate a shift in the balance between cell proliferation and apoptosis that contributes to the regulation of the spermatogenic cycle and germ cells pool of L. taeniatus kept in captivity.

In the Juramento Reservoir, south‐eastern Brazil, the white piranha Serrasalmus brandtii showed a prolonged reproductive season, with evidence for multiple spawning and a reproductive peak associated with seasonal rains. The egg surface exhibited a honeycomb‐like pore canal arrangement and an adhesive apparatus surrounding the micropyle. Electron microscopic analysis suggests a role for the micropylar cell and neighbouring follicular cells in secretion of substances for egg attachment.

To study reproduction and embryogenesis, Pimelodus maculatus specimens were kept in captivity and captured bimonthly during 1 year. Gonads samples (211 specimens) were collected and submitted to routine histological techniques. Pimelodus maculatus prepared to reproduce when water temperature was high, and even reached advanced maturation but did not spawn in captivity. Spent fish gonads were not documented, and atretic follicles were frequent (60%) in late maturation females. When then submitted to hypophysation, 70% of the females responded positively to hormonal treatment. Oocyte extrusion occurred 8 h after a second hormonal injection at 26°C. The fertilisation rate was 65.1 ± 9.2% at 24°C. Recently spawned oocytes of P. maculatus were spherical, non-adhesive, yellow in colour, with an average diameter of 1113.92 ± 37.02 μm and covered by a thick gelatinous layer. Blastopore closure occurred 7 h and 30 min after fertilisation. Embryonic development was completed within 18 h after fertilisation. The results of this work provide important knowledge for the handling and cultivation of not only P. maculatus, but other species of potential value for fish culture.

Journal of Applied IchthyologyVolume 33, Issue 6 p. 1118-1124 ORIGINAL ARTICLE Comparative analyses of reproductive activity in Schizodon knerii (Steindachner, 1875) (Characiformes: Anostomidae) in three sections of the São Francisco River basin L. de Esquivel Dias Brandão, L. de Esquivel Dias Brandão Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorA. Virtude do Nascimento, A. Virtude do Nascimento Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorL. Marcon, L. Marcon Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorJ. Enemir dos Santos, J. Enemir dos Santos Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorK. Biana Santiago, K. Biana Santiago Hydrobiology and Fish Hatchery Station of Três Marias, Três Marias, Minas Gerais, BrazilSearch for more papers by this authorE. Rizzo, E. Rizzo Morphology Department, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorN. Bazzoli, Corresponding Author N. Bazzoli bazzoli@pucminas.br Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil Morphology Department, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil Correspondence Nilo Bazzoli, Programa de Pós-Graduação em Biologia de Vertebrados, Dom José Gaspar, Belo Horizonte-MG, Brazil. Email: bazzoli@pucminas.brSearch for more papers by this author L. de Esquivel Dias Brandão, L. de Esquivel Dias Brandão Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorA. Virtude do Nascimento, A. Virtude do Nascimento Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorL. Marcon, L. Marcon Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorJ. Enemir dos Santos, J. Enemir dos Santos Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorK. Biana Santiago, K. Biana Santiago Hydrobiology and Fish Hatchery Station of Três Marias, Três Marias, Minas Gerais, BrazilSearch for more papers by this authorE. Rizzo, E. Rizzo Morphology Department, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, BrazilSearch for more papers by this authorN. Bazzoli, Corresponding Author N. Bazzoli bazzoli@pucminas.br Graduate Program on Biology of Vertebrates, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil Morphology Department, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil Correspondence Nilo Bazzoli, Programa de Pós-Graduação em Biologia de Vertebrados, Dom José Gaspar, Belo Horizonte-MG, Brazil. Email: bazzoli@pucminas.brSearch for more papers by this author First published: 04 August 2017 https://doi.org/10.1111/jai.13457Citations: 7Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Summary This paper aims to establish possible changes in the main reproductive parameters of the so-called piau-branco, Schizodon knerii, in three sections of the São Francisco River basin. Fish (n = 388) were captured quarterly between May 2012 and April 2013 from three sections of the São Francisco River (SFR): section 1 = Três Marias Reservoir (TMR), a lentic environment; section 2 = SFR, the first 34 km downstream of TMR, a lotic environment in which the temperature, oxygen levels, and flow are not suitable for reproduction; section 3 = SFR, 34–54 km downstream from TMR after the confluence with the Abaeté River, a lotic environment in which temperature, oxygen levels and flow are suitable for reproduction. In section 2, females and males showed lower values of total length and body weight in relation to fish from sections 1 and 3. The reproductive mode of S. knerii in sections 1 and 3 exhibited a prolonged reproductive period, parceled spawning, and a reproductive peak from January to March. In section 2, neither spawning females or spermiated males were captured, probably due to the fact that this section receives cold water with low oxygen levels from the hypolimium of the dam that presents thermal stratification in the summer. This study showed in section 2, immediately downstream of the Três Marias Reservoir, that S. knerii does not reproduce successfully. Citing Literature Volume33, Issue6December 2017Pages 1118-1124 RelatedInformation

Early development from the egg fertilization to complete resorption of the yolk-sac is a critical period in the life cycle of teleost fish. Knowledge of this process provides essential parameters for aquaculture and identification of spawning sites in the wild. In the present study, a comparative morphological analysis of the oocyte surface as well as early development was performed in four commercially valuable species from the São Francisco River: Brycon orthotaenia, Leporinus obtusidens, Prochilodus argenteus, and Salminus franciscanus. Stripped oocytes, embryo, and yolk-sac larvae were analyzed by scanning electron microscopy (SEM) and histology. A set of 10 lectins was used for investigation of lectin-binding pattern in oocytes. In the four species, the outer layer of the zona radiata reacted to most lectins, indicating complex polysaccharides at the oocyte surface while no reactivity was detected in the inner zona radiata and yolk globules. Typical structural arrangements were recognized at the micropylar region by SEM. The four species showed nonadhesive eggs, short embryonic period (18-20 h at 24 ± 1°C), and poorly developed larvae at hatching. At 24 h posthatching (hph), larvae of the four species had neuromasts on the body surface. Rudimentary cement glands for larval attachment were identified on the cephalic region at 24 and 48 hph in B. orthotaenia and S. franciscanus, and following they were in regression. The time for whole yolk resorption varied among species from 48 to 120 hph, occurring earlier in S. franciscanus, followed by B. orthotaenia, P. argenteus, and L. obtusidens. The formation of the digestive tract and the mouth opening indicated initiation of exogenous feeding 24 h before complete resorption of the yolk. Together, our data indicate similarities in the early development among species that may be related to the life cycle strategies and phylogeny.

The success of fishes in different environments is related with the variation of reproductive strategies developed by the systematic group, which is reflected in the morphology of the reproductive system and can have ecological and evolutionary implications. This study comparatively analyzed the morphological characteristics of the male and female reproductive systems of ostariophysan fish species from the upper Das Velhas River in the São Francisco River basin, Brazil. In order to accomplish this, 393 specimens belonging to seven fish species were sampled between April 2010 and June 2015 for histological, ultrastructural, histochemical, and morphometric analyses. All the species examined have anastomosing tubular testes with unrestricted distribution of spermatogonia. Astyanax bimaculatus, A. fasciatus, A. scabripinnis, and Harttia torrenticola had their spermatozoa embedded in a glycoprotein secretion within the tubule lumen. Most species had type I spermiogenesis, whereas Rhamdia quelen had type III spermiogenesis. While all females examined had asynchronous oocyte development, there were remarkable morphological, histochemical, and morphometric differences in the ovarian follicles and enveloping layers. Hoplias malabaricus and H. torrenticola, which exhibit parental care behaviour, had a significantly larger diameter of vitellogenic oocytes and larger spermatozoa nuclei. Apareiodon ibitiensis, H. torrenticola, and A. scabripinnis, species that have rheophilic preferences, exhibited a thicker zona radiata than the other species examined. The follicular cells of R. quelen and H. torrenticola were columnar and produced a jelly coat and mucosubstances, respectively. The females of the seven fish species studied show a correlation of the reproductive strategies with the reproductive system morphology, while males retained more similar morphological characteristics between species. J. Morphol. 278:170-181, 2017. © 2016 Wiley Periodicals,Inc.

The alterations to the hydrologic regime downstream from hydroelectric dams may cause an impact on the reproductive success of fishes. This study aimed to analyse the influence of the physical and chemical parameters of the water of the Grande and Pardo Rivers on gonadal maturation, oocyte diameter, follicular atresia and biological indices of Pimelodus maculatus collected from three river sections: Grande River, downstream from the Porto Colômbia dam (S1), Grande River, downstream from the confluence with the Pardo River (S2) and in the Pardo River channel (S3). Males and females captured in S1 presented significantly higher average values for total length and body weight than those captured in S2 and S3. The gonadosomatic index values were significantly higher in fish collected in S3 and the Fulton condition factor did not show significant differences in fish collected from the three sections. The oocyte diameter, the follicular cells height and the zona pellucida thickness did not show any statistical differences between the sections. Conductivity presented a significant difference between S1 and S3 and during the reproductive period, water transparency presented similar values in the two sampling sections of the Grande River, but a much lower value in the Pardo River. A low frequency of fish with reproductive activity was registered in S1, whereas in S2 and S3 higher frequencies were recorded, emphasising the need of preserving the tributaries for the reproductive success of P. maculatus of the Grande River in south-eastern Brazil.

In fishes, gonad morphology is an important parameter to understand the reproductive biology, phylogenetic relationships and systematic studies. The main objective of this study was to make a comparative analysis of the morphology of mature ovary and testis in six fish species of the family Anostomidae. A total of 212 specimens, presenting maturing gonads, were captured from the São Francisco River, Três Marias Reservoir area, in Southeastern Brazil, between August 2008 and December 2010. The six analyzed species had mature ovaries and showed a grayish color. In vitellogenic oocytes (VO), cortical alveoli (CA) were composed by small vesicles in all Leporinus species, but in Leporellus vittatus and Schizodon knerii the CA were large vesicles. However, the CA of all species showed similar histochemical content. The pellucid zone consists of two layers to all species, but it was thicker in S. knerii (11.5 ± 1.8 µm) than in L. vittatus (9.0 ± 0.8 µm) and Leporinus species (3.5 ± 0.6 - 8.7 ± 0.9 µm). Follicular cells of the VO were respectively cubic and prismatic in animal and vegetative poles of S. knerii (22.3 ± 3.2 and 61.1 ± 9.6 µm), and squamous in the other species (1.3 ± 0.3 - 1.6 ± 0.3 µm). Females of S. knerii and males of L. vittatus showed lower values of gonadosomatic index (GSI) than the other assessed species. All evaluated species presented testicular morphology similar to most neotropical Characiformes, with unrestricted spermatogonial testis and anastomosing tubular organization of seminiferous tubules. Phenotypical differences in the vitellogenic oocyte of Anostomidae fishes, confirmed the taxonomic position of S. knerii as different genus in relation to Leporinus and L. vittatus. Despite being placed in different genera, the characteristics of the vitellogenic oocytes of L. vittatus were similar to those found in the studied Leporinus.

Abstract: In order to assess the influence of the Três Marias dam on the reproduction of the white piranha, Serrasalmus brandtii, 1569 specimens captured from June 2011 to May 2012 in three sections of the São Francisco River basin were analyzed: section 1 = Três Marias reservoir (TMR); section 2 = São Francisco River (SFR) segment immediately downstream of TMR; and section 3 = SFR segment at the confluence with the Abaeté River. Total length (TL), body weight (BW), gonadosomatic index (GSI), and gonadal maturation stages were determined for each specimen, while vitellogenic follicle diameter, and absolute (AF) and relative (RF) fecundities were also determined for females. Reproductive activity, including spawned females and spermed males, was recorded throughout the year in the three river segments. Higher frequencies of females and males at the maturing/mature stage were found in the November/December and January/February, which coincided with the period of higher temperature, rainfall, and dissolved oxygen concentration. Mean GSI and vitellogenic follicle diameter were higher in sections 1 and 3 than in section 2 (P &lt;0.05), while AF and RF were higher in section 1 (P &lt;0.05) than in sections 2 and 3. The results of the present study showed that S. brandtii had lower reproductive performance in section 2, probably due to thermal disturbances caused by the dam, thus confirming the influence of dams on the reproduction of fish downstream from hydroelectric plant reservoirs.

Food restriction is part of the life cycle of many fish species; however, nutritional deficiency may negatively influence gametogenesis and gonadal maturation. The aim of this study was to evaluate the effects of food restriction on the spermatogenesis of Nile tilapia. For this, adult males were submitted to starvation and refeeding cycles (alternating periods of starvation and feeding) for 7, 14, 21, and 28 days. After 7 days of starvation, glycaemic and lipid levels were significantly reduced, followed by reduction of plasma testosterone (T) and 11-ketotestosterone (11-KT). In addition, reduced proliferation of spermatogonia and increased apoptosis of spermatocytes, spermatids, and spermatozoa was observed in starvation groups. In the refeeding groups, the sex steroids and the proportion of germ cells had no significant alterations compared to the control group, except for spermatozoa. In this sense, the present study suggests that starvation after 7 days progressively reduces T and 11-TK, resulting in damage to the production of spermatogenic cells, while refeeding may delay spermatogenesis but does not lead to testicular impairment.

Rizzo E., Battisti C.: Habitat preferences of Anatidae (Aves, Anseriformes) in a Mediterranean patchy wetland (central Italy). Ekologia (Bratislava), Vol. 28, No. 1, p. 66–73, 2009. The habitat preferences of a set of duck species (Anseriformes, Anatidae) occurring in a Mediterranean remnant wetland of central Italy were assessed in respect to four habitat types selected a priori (reed beds, flooded meadows, uncultivated fields, flooded pastures). We obtained 1392 records from five species. Wetland fragment studied appears a patchy mosaic of habitat differently utilized by the duck species. Mallard (Anas platyrhynchos) occurs more frequently in reed beds, garganey (Anas querquedula) in the flooded meadows, wigeon (Anas penelope), teal (Anas crecca), shoveler (Anas clypeata) in the flooded pastures. We evidenced two groups that appear different in regard to their specialization: species linked to flooded pastures (wigeon, teal, shoveler), more specialists, with lower niche breadth index ( 0.4). Comparing the species belonging to the two groups, they show low values of niche overlap index. At local scale and around a yearly cycle, the presence of different habitat types induces a patchiness at local scale that may favour the presence of duck species with different ecology.

Summary This study presents, for the first time, information on the eggs and early development of F ranciscodoras marmoratus , fish of S ão F rancisco river, B razil. To analyse the egg ultrastructure and morphological events of embryogenesis, a total of 36 F . marmoratus specimens (18 males and 18 females) were captured and subjected to spawning induction. Gametes were collected by manual extrusion, and fertilization was conducted using the dry method. After fertilization, eggs were kept in incubators with water temperature of 24° C . The embryonic development was monitored using a stereomicroscope until hatching. There was a 67% positive response to hypophysation by the females and the fertilization rate was 73.8 ± 6.2%. The oocytes are discoid, yellow, adhesive and covered by a thick jelly coat. Under the electron scanning microscope, the oocytes presented a surface with pore canals and funnel‐shaped micropyle with a smooth vestibule. Recently extruded oocytes had a mean diameter of 1.27 ± 0.4 mm and after hydration was 1.91 ± 0.05 mm. The jelly coat was 0.34 ± 0.03 mm thickness, and the perivitelline space was 0.19 ± 0.04 mm. Eight phases of the embryonic development were identified, and embryogenesis was completed at 47 h after fertilization, at 24° C water temperature. The recently hatched larvae had 2.76 ± 0.57 mm of total length. These results provide useful information for the successful breeding and reproductive strategies of fishes.

In order to exploit native fish species for aquaculture, basic parameters of artificial reproducetion and estimates of reproductive potential for this fish must be determined to improve hatchery success.We analyze seven Brazilian commercial fish.Spawning was induced using the hypophysation method, with injection of crude carp pituitary extract (CCPE).Characiformes species signaled the spawning time with behavioral alterations (usually circular movements). The time of oocyte extrusion varied from 5.3 ± 0.3 h inSalminus franciscanus to 8.6 ± 0.1 h in Prochilodus argenteus after the second CCPE injection.The greatest diameter of a vitellogenic oocyte was registered for P. argenteus (873.9 ± 122.2 μm) and the smallest was for Pimelodus maculates (465.4 ± 36.3 μm).The diameter of vitellogenic oocytes was very similar among species belonging to the same family.The highest ROI values were registered for Prochilodus costatus(27.0± 3.5 μm) and P. argenteus (23.4 ± 3.7 μm), while the lowest values were found in Pseudoplatystoma corruscans (4.6 ± 0.9 μm) and P. maculatus (6.0 ± 1.3 μm).Absolute fecundity (number of oocytes released at spawning) was lowest in P. maculatus and highest in P. corrus-cans.Relative fecundity (RF) presented a high correlation (r = 0.98 to 0.99) with gonad weight, indicating high efficiency of spawning.The RF also presented a high correlation with body weight (r = 0.88 to 0.97) and total length (r = 0.86 to 0.92).The highest RF was registered for Leporinus obtusidens, and the lowest was for P. corruscans.Released fecundity had a negative correlation with the diameter of vitellogenic oocytes and with the height of the follicular cells, and a positive correlation with the thickness of the zona pelucida.These results indicate that the species studied herein are suitable candidates for aquaculture due to their reproductive and zootechnical characteristics.

Bisphenol A (BPA) is an organic synthetic compound used in the plastic industry with endocrine disrupting activity. Although it is frequently found in surface waters, few studies have investigated its impact on fish gametogenesis, particularly when associated with natural stressors. In this regard, the present study evaluated BPA toxicity on spermatogenesis in the lambari Astyanax bimaculatus under controlled conditions and its interactive effects with water temperature. Adult specimens were exposed in duplicate to 40 μg/L and 400 μg/L BPA at 23 °C and 28 °C for 21 days; the control group did not receive BPA. Testicular samples were collected and analyzed using different cellular and molecular techniques. The results showed a significant reduction in the gonadosomatic index in the BPA-treated groups at both temperatures. A decrease in the testicular levels of 11-ketotestosterone was observed in the 400 μg/L BPA group at 23 °C, 17β-estradiol increased significantly in the treated groups at 28 °C, and vitellogenin showed no difference between the treatments. The morphometric analysis of spermatogenesis revealed a significant increase in the proportion of spermatogonia, spermatocytes, and Sertoli cells in the treated groups, with a higher proportion at 23 °C than at 28 °C. Otherwise, the proportion of spermatozoa was significantly lower in the BPA-treated groups, with a greater reduction at 23 °C. In addition, BPA also stimulated spermatogonial proliferation in the treated groups, but apoptosis was significantly increased in spermatids at 23 °C. Testis-ova, cell degeneration, and chromatin alterations in spermatids and Sertoli cells were observed in the germinal epithelium of the BPA-treated groups. The integrated biomarker response (IBR) index revealed that the analyzed endpoints are suitable for assessing estrogenic contamination. Taken together, our results indicate that the interactive effects of BPA and temperature contribute to the impairment of spermatogenesis in A. bimaculatus with more severe effects observed on sperm production at 23 °C than at 28 °C.

Summary Curimatella lepidura and Steindachnerina elegans are small forage fish, constituting an important link in the food chain, serving as food for larger commercial fish. In this study, characteristics of the eggs, of the oocyte's surface ultrastructure and of the embryogenesis are first described for these species. Absolute fecundity was 40864 ± 8769 oocytes for C. lepidura and 22089 ± 8710 oocytes for S. elegans . Oocytes of both species are yellowish, weakly adhesive and with a post‐fertilization diameter of 1019.5 ± 20.6 μm and 978.75 ± 29.16 μm for C. lepidura and S. elegans , respectively. The ultrastructural analysis, using scanning electron microscopy, showed that the oocyte's surface of both species has pore canals over the entire surface and a funnel‐shaped micropyle. At 24°C, the embryonic development of C. lepidura was completed 25 h after fertilization, and blastopore closure occurred in 7 h 30 min. In S. elegans , larvae hatched 20 h after fertilization, and blastopore closure occurred in 7 h 15 min. The fertilization rate was 74.5 ± 7.96 and 71.2 ± 10.8% for C. lepidura and S. elegans , respectively. This study provides important support for clarifying phylogenetic relationships and in ecological and zoological understanding of Neotropical Curimatidae fish.

ABSTRACT The Nile tilapia is one of the most important fish species for aquaculture worldwide. Understanding their reproductive biology is essential for improving their aquaculture methods. The morphological and quantitative dynamics of ovarian recrudescence of Oreochromis niloticus was studied for 21 days postspawning. To accomplish this, breeding females were kept in controlled conditions and ovarian samples were collected weekly for histological, ultrastructural and morphometric analyses. Ovarian follicle morphology revealed an intense synthesis activity of the follicular cells, which actively contributed to formation of the zona radiata and oocyte development following spawning. Recently spawned ovaries contained follicles at all developmental stages, but they were predominantly early primary growth (∼42%) and full‐grown follicles (∼20%). Remnants of spawning, postovulatory follicle complexes represented approximately 5% of the former ovarian follicles immediately after spawning, and less than 1% after 7 days. Atretic follicles accounted for approximately 2% of the follicles studied during the period. The stock of primary growth follicles was stable during ovarian recrudescence, indicating their availability for continuous recruitment. Only the frequency of full‐grown follicles significantly increased in the ovaries during recrudescence, representing approximately 35% of the follicles 21 days postspawning. The diameters of all follicles were significantly different between the periods analyzed. The ovaries' morphological characteristics, the maintenance of young follicles stocks and the gradual and significant increase in the proportion and diameter of full‐grown follicles showed a rapid ovarian recovery and follicular growth of O. niloticus , in 21 days at 29.5°C, necessary for the next spawning. J. Morphol. 275:348–356, 2014. © 2013 Wiley Periodicals, Inc.

Abstract Despite its relevance for ecology, evolution and conservation of species, natural hybridization and hybrids biology are still poorly studied in freshwater fish. Here, we tested the hypothesis that sympatric species Astyanax paranae and A . fasciatus are able to interbreed in the natural environment and presented evidence for the first record of hybridization between these species. We analyzed anatomical traits, gametogenesis, reproductive biology, and genetic variations of the COI and S7 genes of both species and putative hybrids. Intermediate morphometric and meristic features were observed in hybrids when compared to A . paranae and A . fasciatus . Overlap in reproductive season was showed for these species, with greater reproductive activity from August to January, but hybrids did not present any sign of gonadal maturation. Oogonia and perinucleolar follicles as well as spermatogonia and primary spermatocytes were found in hybrids, but previtellogenic and vitellogenic follicles, spermatids, and spermatozoa were absent. Moreover, several alterations in gametogenesis were detected, such as interrupted meiosis in both males and females, vacuolated and degenerated germ cells, increased interstitial tissue, and presence of immune cells. Molecular analyses supported the hypothesis of hybridization between A . paranae and A . fasciatus . Overall, our multidisciplinary approach also provides strong evidence that hybrids are infertile.

Sexual differentiation and early gonadal development are critical events in vertebrate reproduction. In this study, the initial testis development and expression of the Vasa, Nanos2 and Sox9 proteins were examined in Nile tilapia Oreochromis niloticus submitted to induced sex reversal. To that end, 150O. niloticus larvae at 5 days post-hatching (dph) were kept in nurseries with no hormonal addition (control group) and 150 larvae were kept with feed containing 17α-methyltestosterone to induce male sex reversal (treated group). Morphological sexual differentiation of Nile tilapia occurred between 21 and 25 dph and sex reversal resulted in 94% males, whereas the control group presented 53% males. During sexual differentiation, gonocytes (Gon) were the predominant germ cells, which decreased and disappeared after that stage in both groups. Undifferentiated spermatogonia (Aund) were identified at 21 dph in the control group and at 23 dph in the treated group. Differentiated spermatogonia (Adiff) were found at 23 dph in both groups. Vasa and Nanos2 occurred in Gon, Aund and Adiff and there were no significant differences between groups. Vasa-labelled Adiff increased at 50 dph in both groups and Nanos2 presented a high proportion of labelled germ cells during sampling. Sertoli cells expressed Sox9 throughout the experiment and its expression was significantly greater during sexual differentiation in the control group. The results indicate that hormonal treatment did not alter initial testis development and expression of Vasa and Nanos2 in Nile tilapia, although lower expression of Sox9 and a delay in sexual differentiation was detected in the treated group.

Summary The present study evaluated the effects of low salinity on the early larval development of Oreochromis niloticus , specifically histological damage to white muscle, morphology of the yolk-sac surface and trunk area, and molecular expression of apoptosis and cell proliferation biomarkers. Newly hatched larvae were submitted to four salinity treatments for a period of 48 or 72 h, in duplicate: (S 0 ) freshwater, (S 2 ) 2 g l −1 , (S4) 4 g l −1 , and (S 6 ) 6 g l −1 NaCl. Larval development was examined using histology, electron microscopy, enzyme-linked immunosorbent assay (ELISA), and morphometry. At the yolk-sac surface, larvae of S 4 and S 6 displayed alterations to the apical opening of chloride cells that may be related to osmotic expenditure caused by the increased salinity. Caspase-3 expression did not differ significantly among treatments, however significantly lower proliferating cell nuclear antigen (PCNA) expression ( P &lt; 0.05) suggested minor cell proliferation in larvae of S 4 and S 6 compared with S 0 and S 2 . Furthermore, there was a significant reduction in both trunk area and percentage of normal white muscle fibres (WF) in larvae of S 4 and S 6 . Vacuolated areas and myofibrils concentrated at the cell periphery and found in the white muscle from larvae exposed to saline environments suggested disturbance to muscle development. Oedema and mononuclear infiltrate were also observed in the white muscle of S 4 and S 6 larvae. Together these results indicated that treatments with 4 and 6 g l −1 NaCl may cause osmoregulation expenditure, morphological alterations to the yolk-sac surface and histological damage to skeletal muscle that negatively affected the early larval development of O. niloticus .

The reproduction of Iheringichthys labrosus (Lütken, 1874) from the Turvo River, Brazil, was studied using anatomical, biometric, histological, and ultrastructural techniques. Between April 2014 and March 2015, a total of 278 males and 512 females were captured bimonthly. The testes of Iheringichthys labrosus are fringed and possess a cranial spermatogenic region and an exclusively secretory caudal region. Histologically, the cranial region is composed of seminiferous tubules with spermatogenesis being completed in cysts. The spermatozoa are of the primitive type with a spherical head and have a rudimentary intermediate piece and a long tail with an axonemic arrangement of 9 + 2. The caudal region does not form an individualized gland, and cells in this testis area have characteristics of protein secretion. A variable density electron-dense secretion accumulates in the cisternae of the rough endoplasmic reticulum in the lumen of the seminiferous tubules and in the testicular ducts during maturation. The cortical alveoli are discontinuous, and the zona pellucida consists of three layers crossed by pore canals, and the follicular cells are squamous in the early stages of oogenesis and cuboidal in advanced stages. The gonadosomatic index was associated with the maturation of the gonads while the condition factor indicated that the fish feed less and utilize adipose reserves during the reproductive period. Males and females reproductively functional throughout the year with spawning being partial or multiple, similar to that reported in studies of the species in lentic environments.

Cytological and cytochemical studies were carried out to investigate the surface characteristics of oocytes of four teleost species from the São Francisco river. The fishes were submitted to hypophysation at the Três Marias Hybrobiology and Fishculture Station, Minas Gerais, Brazil, in January 1996. Postspawning, oocytes of the curimatãs Prochilodus affinis, Prochilodus marggravii and dourado Salminus brasiliensis were surrounded by a thick, three-layered zona pellucida with radial striae. The surface of spawned oocytes of the surubim, Pseudoplatystoma coruscans, was comprised of mucous coat located externally to a thin, two-layered and striated zona pellucida. Oocyte activation during fertilization, lead to cortical reaction, formation of a perivitelline space, reduction of the thickness of the zona pellucida and increase in the oocyte diameter in the four species. Following fertilization, many spermatozoa were embedded in the mucous coat of the surubim oocytes. During embryogenesis, this later coating became thicker, diffuse and less viscous while the zona pellucida (chorion) was thinner in all studied species. Cytochemical analyses indicated species-specific differences in the oocyte surface after spawning. It was suggested that the mucous coat of surubim oocytes play a functional role during fertilization. The knowledge of the morphology of the oocyte surface of teleost is important for our understanding of the interactions between their eggs and surrounding environment and may also contribute significantly to phylogenetic studies.

Summary The aim of the present study was to characterize biopsied and stripped oocytes from the Brazilian endangered teleost pirapitinga ( Brycon nattereri ) using histochemical and morphological analyses. Biopsied oocytes had a mean diameter of 2.225 mm (modal diameter: 2.312 mm), complete vitellogenesis and a central or slightly eccentric nucleus. Neutral polysaccharides were detected in the follicular cells, zona radiata and yolk globules, while acidic polysaccharides were detected in the follicular cells and cortical alveoli. Ten out of the 19 females treated with two doses of carp pituitary extract (cPE) released oocytes, which were also analysed. Stripping occurred 292 ± 39 degree-hours after the second dose of cPE and led to a mean spawning weight of 36.2 g, 10% spawning index, 241 oocytes/g of ova, 8222 oocytes/female and 23 oocytes/g of body weight. Stripped oocytes had a mean diameter of 2.33 mm and a mode at 2.375 mm, were weakly adhesive and coloration ranged from wine to brown. Under scanning electron microscopy, stripped oocytes exhibited a single funnel-shaped micropyle located at the animal pole and a zona radiata that measured 7.7 μm in thickness with eight pore canals/μm 2 . Oocyte morphology in Brycon nattereri is similar to that found in other species of the genus, except for the larger size and weaker adhesiveness. These findings provide essential information for a better understanding of the reproductive biology of B. nattereri and the establishment of conservation measures for this threatened species.

In Brazil, fishing in continental waters is prohibited from November to February, the rainy season, when most commercially important fish species are reproductively active. Brycon nattereri is a native species to the Paraná, Tocantins, and São Francisco River basins in Brazil and is on the national list of species threatened with extinction. The goal of this study was to analyse the main reproductive variables of B. nattereri from the Lourenço Velho River, located in the Paraná River basin, south-eastern Brazil. From 2013–2016, 326 specimens (156 females and 170 males) were caught bimonthly using gill nets. Biometric data, gonadosomatic index (GSI), and fecundity were determined for each specimen. The gonadal maturation stages and the breeding season were established. There were relatively greater GSI values for males and average values were similar to those of females, an uncommon feature in Neotropical freshwater fish. The greatest frequencies of mature fish occurred from April to July in the dry season, which is when there are least ambient temperatures. The fecundity for body weight varied from 16,300 to 62,800 oocytes per female and fully developed vitellogenic oocytes had a mean diameter of 1175 ± 278.87 μm. These results indicate that B. nattereri breeds in the dry season when the water temperature is colder and, therefore, protection from fishing of this species during this season needs to be established.

ABSTRACT River impoundments for electricity generation lead to environmental changes which severely affect fish migration and species richness. However, little is known about their effect on the genetic structure and population dynamics downstream from the reservoir. Here, we analyzed a set of ten microsatellite loci of Prochilodus lineatus, an important South American migratory fish. Specimens (n = 150) were sampled from five sites in a remnant lotic system that includes sections of the Grande, Pardo and Mogi Guaçu rivers, southeastern Brazil. The data showed that all microsatellites were polymorphic with the allele number per locus ranging from 5 to 32, and genetic diversity (H e ) varied from 0.74 to 0.80. Indices of genetic differentiation and Bayesian analysis showed a significant genetic structure and three genetic clusters inhabiting this river system. An asymmetric gene flow suggests source-sink metapopulation dynamics from tributaries (genetic source) to the main river (genetic sink). A genetic cluster that was not detected in the upper Mogi and Pardo rivers tributaries may indicate there is a “trapped gene pool” downstream from the Porto Colômbia dam. Thus, here we provide new insights into the genetic structure and population dynamics of a migratory fish species in a highly dammed river basin.

A morphological study of the yolk nuc/eus in previtellogenic oocytes from A. bimaculatus has been carried out.Six phases of development were described from its formation closed to the oocyte nuc/eus to its dispersion in the periferic ooplasm Histochemical techniques indicate proteins, lipUis and RNA in the yolk nuc/eus of A. bimaculatus, but there are no carbohy drate in this stru cture.The origin and fUn ctional activity ofthe teleost yolk nuc/eus are discussed. INTRODUÇÃO