Growth and reproductive characteristics of Rhamdia quelen males fed on different digestible energy levels in the reproductive phase

The growth, hepatocyte morphology, gonadal maturation and semen and sperm characteristics of silver catfish (Rhamdia quelen) were assessed. Males were fed for 210 days with food pellets containing 30% digestible protein (DP) and digestible energy (DE) corresponding to 2850, 3100, 3350, 3600, and 3850 kcal DE kg diet− 1. The length, weight, weight gain, and condition factor were evaluated. Between October and February hormones were administrated (carp pituitary extract) and semen was collected to evaluate the semen volume, semen pH, sperm motility, sperm velocity, sperm survival, sperm concentration and sperm normality. In February, six animals from each treatment were euthanized and dissected to measure the viscerosomatic, hepatosomatic and gonadosomatic indices, the histological maturation stage and the average hepatocyte area. Monthly changes were observed only (p < 0.05) in seminal parameters, indicating the occurrence of a reproductive peak in November and December. Food pellets containing 30% digestible protein and 2850 kcal DE kg diet− 1 may be used as a male silver catfish diet without a loss of growth or reproductive performance.

► The male silver catfish reproductive peak occurs in November and December. ► Energy levels between 2.850 kcal and 3.850 kcal did not affect hepatocyte morphology. ► The same levels did not affect the animal or reproductive performance to silver catfish males. ► Increasing information on broodstock nutrition.