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-The objective of this study was to evaluate the effects of water volume and water temperature on the sperm motility duration and the number of spermatozoa, and the water volume on the fertilization rates of oocytes of Rhinelepis aspera. Experiments were carried out to evaluate the effect of semen dilutions (1.74×10-5 , 1.74×10 -4 , 1.74×10 -3 , 1.74×10 -2 , 1.74×10 -1 and 1.00 mL of sperm.mL -1 of water) and water temperature (5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 °C) on spermatozoa motility duration. In addition, the effects of insemination dose (7×10 3 , 7×10 4 , 7×10 5 , 7×10 6 and 7×10 7 spermatozoa.oocyte -1 ) and water volume (1.0, 30.0, 60.0, 90.0 and 120.0 mL water.2.0 mL -1 oocytes) on the artificial fertilization rates of oocytes were evaluated. The longest sperm motility duration were observed for the semen dilution of 1.74×10 -5 mL semen.mL -1 water and in water at 5 °C. The highest fertilization rates were obtained for insemination doses between 7.00×10 3 and 1.23×10 7 spermatozoa. oocyte -1 and water volume of 28.11 mL water.2.0 mL -1 oocytes.

This study was conducted to evaluate the effects of different diet energy levels on animal performance. Specifically, this investigation examined the reproductive and histological aspects of the liver and gonads of female silver catfish (Rhamdia quelen). These fish were fed for 210 days with diets containing 30% digestible protein (DP) and digestible energy (DE) that corresponded to 11.93, 12.98, 14.03, 15.07 and 16.12 MJ of DE kg−1. The initial and final lengths, weights, and weight gains, the visceral, gonadal, and hepatosomatic indices, and the histological parameters hepatocytes area and gonadal stages were evaluated. In the reproductive season, the fish were submitted to an artificial reproduction protocol and the percentage of spawning females and their relative and absolute fecundity were evaluated. DE did not affect reproductive or animal performance aspects (P > 0.05). Cytoplasmic vacuoles in hepatocytes were observed in higher DE levels. Thus, female Rhamdia quelen can be fed a diet of 30% DP with 11.93 MJ of DE kg−1 without reproductive or performance losses.

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-This study was carried out to evaluate the influence of different levels of digestible energy and digestible protein in diets of Nile tilapia (Oreochromis niloticus) broodstock on offspring growth during sex reversal stage. A total of 2,700 post-larvae (8.2±0.001 mg) derived from breeders fed nine diets with distinct levels of digestible protein (28, 34 and 40% DP) and digestible energy (2,800; 3,400; and 4,000 kcal DE.kg -1 ) were stored in twenty-seven 70 L tanks. After 30 days of growth, their average final weight (AFW, g), average weight gain (AWG, g), final standard length (SL, cm), condition factor (CF), specific growth rate (SGR, %/day), stock uniformity (UNI, %), survival (SUR, %) and sex reversal rate (SRR, %) were measured. Although female nutrition is thought to influence the performance or quality of progeny during early life stages, no influence of diets supplied to broodstock was detected on any parameter. Nonetheless, the offspring presented commercially satisfactory growth rates. Thus, diets containing 28% of digestible protein and 2,800 kcal of digestible energy.kg of diet -1 can be used to feed Nile tilapia broodstock without jeopardizing offspring performance during the sex reversal phase.