Histochemical and morphological features of biopsied and stripped oocytes from the Brazilian endangered teleost pirapitinga, Brycon nattereri (Characiformes)

Abstract

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/μm2. 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.

Embryonic development and larval growth of Brycon nattereri Günther, 1864 (Characidae) and its implications for captive rearing

“…In this study, the closure of the blastopore occurred around 26 h and hatching began after 50 h of fertilization, when incubated at 19°C. This temperature is usually observed in this region during the reproductive period of the species (Viveiros et al ., 2012a; Maria et al ., 2015), therefore it may be considered as a comfortable temperature for this species. Brycon nattereri embryogenesis can be considered as long compared with other species of the genus Brycon , such as B .…”

“…It has been recently reported that the gonad maturation of B . nattereri broodstocks kept in captivity, occurred in autumn–winter, in the colder months of the year (Viveiros et al ., 2012a; Maria et al ., 2015), and differs from other species of the genus Brycon , which reproduce in spring–summer (Zaniboni-Filho et al ., 2006). In captivity, the collection of gametes for artificial reproduction of B .…”

“…In captivity, the collection of gametes for artificial reproduction of B. nattereri is possible after hormonal induction (Viveiros et al, 2012a). In this condition, collected sperm is of high quality (Oliveira et al, 2007;Viveiros et al, 2012a), however, stripped oocyte quality and consequently hatching rate is still very poor due to a lack of information about this species (Viveiros et al, 2012a;Maria et al, 2015).…”

Oocyte growth, follicular complex formation and extracellular-matrix remodeling in ovarian maturation of the imperial zebra pleco fish Hypancistrus zebra

“…This method of measuring the cell diameter was adapted from the literature 42 . In our analysis, we measured the cells in two dimensions (2d), as in several previous studies 44 – 46 . The data were tested through one-way analysis of variance (ANOVA), followed by a posteriori Tukey test with 5% significance level (α).…”

Embryogenesis and larval development of migratory matrinchãBrycon orthotaeniaGünther 1864 (Characiformes: Bryconidae)

“…This difference can be attributed to the occurrence of the species in headwater regions where the waters are cold. The largest size of oocytes coupled with cool waters slow the development of pirapitinga when compared to other Brycon species (Lima, Albrecht, Pavanelli, & Vono, 2008;Maria, Orfão, Rizzo, Ninhaus-Silveira, & Viveiros, 2014;Oliveira, Viveiros, Maria, Freitas, & Izaú, 2007).…”