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Astyanax fasciatus. Oocyte developmental stages. PN: perinucleolar (a) (arrow head); CA: cortical alveoli (b) (arrowhead); V: vitellogenic (*) cytoplasm and nucleus (arrow
Source publication
Astyanax fasciatus is a group of neotropical fish with two different diploid chromosome numbers, and in the wild, these individuals are found in sympatry. The annual reproductive cycles of adult females of species with different numbers of chromosomes (G1: 46 chromosomes, low responsiveness to induced spawning; G2: 48 chromosomes, responsive to ind...
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... analyses A descriptive analysis of the ovaries showed the presence of different follicular developmental stages, which allowed for the characterization of their maturation. The oocytes found during the microscopic examination were perinucleolar (PN; Fig. 1a), alveolar cortical (AC; Fig. 1b), vitellogenic (V; Fig. 1c), and atretic (A; Fig. 1d). Nuclear migration (Fig. 1e) was detected in the vitellogenic oocytes as well as a structure called a post-ovulatory follicle (POF; Fig. 1f). The stages were classified as ...
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... analyses A descriptive analysis of the ovaries showed the presence of different follicular developmental stages, which allowed for the characterization of their maturation. The oocytes found during the microscopic examination were perinucleolar (PN; Fig. 1a), alveolar cortical (AC; Fig. 1b), vitellogenic (V; Fig. 1c), and atretic (A; Fig. 1d). Nuclear migration (Fig. 1e) was detected in the vitellogenic oocytes as well as a structure called a post-ovulatory follicle (POF; Fig. 1f). The stages were classified as ...
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... analyses A descriptive analysis of the ovaries showed the presence of different follicular developmental stages, which allowed for the characterization of their maturation. The oocytes found during the microscopic examination were perinucleolar (PN; Fig. 1a), alveolar cortical (AC; Fig. 1b), vitellogenic (V; Fig. 1c), and atretic (A; Fig. 1d). Nuclear migration (Fig. 1e) was detected in the vitellogenic oocytes as well as a structure called a post-ovulatory follicle (POF; Fig. 1f). The stages were classified as ...
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... analyses A descriptive analysis of the ovaries showed the presence of different follicular developmental stages, which allowed for the characterization of their maturation. The oocytes found during the microscopic examination were perinucleolar (PN; Fig. 1a), alveolar cortical (AC; Fig. 1b), vitellogenic (V; Fig. 1c), and atretic (A; Fig. 1d). Nuclear migration (Fig. 1e) was detected in the vitellogenic oocytes as well as a structure called a post-ovulatory follicle (POF; Fig. 1f). The stages were classified as ...
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... analysis of the ovaries showed the presence of different follicular developmental stages, which allowed for the characterization of their maturation. The oocytes found during the microscopic examination were perinucleolar (PN; Fig. 1a), alveolar cortical (AC; Fig. 1b), vitellogenic (V; Fig. 1c), and atretic (A; Fig. 1d). Nuclear migration (Fig. 1e) was detected in the vitellogenic oocytes as well as a structure called a post-ovulatory follicle (POF; Fig. 1f). The stages were classified as ...
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... the characterization of their maturation. The oocytes found during the microscopic examination were perinucleolar (PN; Fig. 1a), alveolar cortical (AC; Fig. 1b), vitellogenic (V; Fig. 1c), and atretic (A; Fig. 1d). Nuclear migration (Fig. 1e) was detected in the vitellogenic oocytes as well as a structure called a post-ovulatory follicle (POF; Fig. 1f). The stages were classified as ...
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... addition, a close relationship exists between the gonadal maturation process and the increasing volume and mass of the ovaries. Thus, the GSI is an important quantitative parameter because its temporal pattern provides information about the reproductive period of the species (Flores et al. 2019). ...
Citations
... We chose A. fasciatus and H. malabaricus, both neotropical species, due to their spread occurrence, ease of capture in the reservoirs of the Tietê River Basin, and because they present different reproductive characteristics. A. fasciatus has an asynchronous gonadal development with a high plasticity in gonadal development based on environmental cues (Brambila-Souza et al., 2019;Carvalho et al., 2009). H. malabaricus, despite presenting an asynchronous gonadal development (Melo et al., 2006), have a more restricted reproductive period, predominantly in the spring and summer (Gomes et al., 2015;Marques et al., 2001). ...
... The data suggest a different responsiveness of both species in triggering an estrogenic response. It can be linked to a higher plasticity in the physiological control of reproduction, which occurred in A. fasciatus (Brambila-Souza et al., 2019). Therefore, even with an increased vtgA gene expression levels, there were no morphological changes in the testes of both species collected in polluted reservoirs. ...
The reproductive physiology of fish can be changed by the presence of pollutants in the water, which act as endocrine disrupting compounds (EDC). We evaluated the impacts of water contaminants in polluted reservoirs acting as possible EDC on the reproductive physiology of Astyanax fasciatus and Hoplias malabaricus males. We used biomarkers with different levels of biological organization. Hoplias malabaricus adult males were collected in the summer and winter at five different sites in the Tietê River Basin: the Ponte Nova reservoir (PN), considered a reference site due to the low anthropogenic influence; the Billings reservoir (BIL) at two different branches; and the Guarapiranga reservoir (GUA) at two different branches. Astyanax fasciatus adult males were collected at PN and BIL. BIL and GUA are subjected to great anthropogenic action. We analyzed gonadal histomorphology, testosterone (T), 11-ketotestosterone (11-KT), estradiol (E2) plasma levels, and gene expression of hepatic vitellogenin (vtgA) and pituitary follicle stimulating hormone (fshβ). In the PN reservoir (reference), the biomarkers analyzed in both species did not differ between the periods analyzed. This is an evidence that the animals keep the same reproductive activity during both seasons. The changes in the plasma concentration of gonadal steroids in both species in polluted reservoirs suggest the presence of EDC compounds in the water and/or adjusts of the physiological setpoint to allow the reproduction in such adverse conditions. The use of vtgA as biomarker suggests the presence of estrogenic compounds, mainly in BIL, but with a more evident response of H. malabaricus. However, even considering physiological changes, both species present testes during the maturation phase that allow the reproduction in an environment with a high degree of pollution.
