Reprodução induzida da pirapitinga-do-sul, Brycon opalinus (Cuvier, 1819), mantida em condições de confinamento

The aim of this study was to describe, for the first time, the embryogenesis and larval growth of the Paraitinga Brycon nattereri Günther, 1864 reared in captivity. After artificial fertilization, eggs were incubated at constant temperature (~19°C) and collected every 15 min during the first 3 h and then every 3 h until hatching. Five larvae were collected daily over 15 days for evaluation of the length, yolk sac volume and specific growth rate. The following stages of embryonic development were identified: zygote, cleavage, gastrula, segmentation and larval. The hatching occurred after 50-54 h, with larvae poorly developed and fully depigmented, devoid of mouth and swimming capacity, presenting 6.32 mm total length and 3.64 mm3 yolk sac volume. The mouth opening was observed between days 3-4 after hatching. The yolk sac absorption was slow during the first 3 days, increasing sharply after this period, being completed on the day 11. During this period there was a decrease in the larval growth rate. After yolk sac absorption, an increase in the growth rate was observed that coincided with the start of exogenous feeding. Cannibalism was not observed during the 15 days of evaluation. The initial development of B. nattereri was slow and poorly developed larvae in relation to other Brycon species, certainly due to the lower temperature required for egg incubation and larval rearing. Other studies are needed in order to develop techniques to improve the methods of incubating eggs and feeding larvae.

Section: Discussionmentioning

confidence: 99%

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

Maria

Ninhaus‐Silveira

Orfão

et al. 2017

“…This failure is probably related to either water volume at the moment of fertilization, oocyte quality, or synchronization of the micropyle opening time (Mylonas et al, 2010). Compared with G2, fertilized eggs were observed in animals from G1, nevertheless compared with the other Characidae species, fertilization rates were considered lower (65%) (Luz et al, 2001;Andrade-Talmelli et al, 2002;Narahara et al, 2002;Weingartner and Zaniboni-Filho, 2005;Honji et al, 2012). Additionally, S. hilarii ATU in both groups were close to those of previous studies performed with Characidae, with only a few slight variations observed according to species.…”

Section: Discussionmentioning

confidence: 99%

Spawning induction and embryonic development of Salminus hilarii (Characiformes: Characidae)

Araújo

Mello

Moreira

et al. 2020

Summary The present study aimed to evaluate two different methods of artificial reproduction induction, and characterize the embryonic development of Salminus hilarii. Different than observed for other tropical fish species, artificial reproduction induction followed by hand-stripping of gametes was considered unfeasible for S. hilarii, as no gamete fertilization was observed. However, females that were induced and spawned naturally presented a fertilization rate of 65.64 ± 0.54%. With a mean temperature of 26.20 ± 0.90ºC it was possible to clearly distinguish a large perivitelline space at 14 min after fertilization (AF) and at 49 min AF more than 50% of the embryos presented two blastomeres, and these cleavages occurred until 1 h 54 min AF. The gastrula phase was characterized at 3 h 56 min AF, and blastopore closure was observed at 8 h 31 min AF. At 9 h 1 min, organogenesis started, with a clear distinction of the yolk mass, embryonic axis, cephalic and caudal regions; at 11 h 51 min AF the embryos already had advanced segmentation and a free tail. Total hatching occurred at 21 h 17 min and after opening the mouth, which occurred at 33 h 9 min, the larvae of S. hilarii presented a strong and characteristic cannibalism. This information can be considered fundamental to improving S. hilarii production in captivity and for collaboration with a conservation programme in the upper Tietê river basin.

“…Relative fecundity was low (23 oocytes/g body weight) and the biopsied oocytes had a large diameter (2.312 mm). Among females of this genus, B. opalinus had a mean of 31 oocytes/g body weight and a mean oocyte diameter of 1.90 mm (Narahara et al ., 2002; Gomiero & Braga, 2007), B. insignis had a mean of 60 oocytes/g body weight and an oocyte diameter of 1.25 mm (Andrade-Talmelli et al ., 2002) and B. orthotaenia had 105 oocytes/g body weight and an oocyte diameter of 1.479 mm (Sato et al ., 2003). The distribution pattern of the diameter of biopsied oocytes has been successfully used to identify females that were suitable for reproduction, as this variable indicates the degree of ovarian development (West, 1990).…”

Section: Discussionmentioning

confidence: 99%

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

Maria

Orfão

Rizzo

et al. 2014

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.