Gonad development and sperm characteristics of male silver catfish (Rhamdia quelen) fed diets with different oil sources / Desenvolvimento gonadal e características espermáticas de jundiás machos (Rhamdia quelen) alimentados com dietas com diferentes fontes de óleo

It is widely accepted that broodstock nutrition or enriched diets with certain compounds greatly impacts fish reproductive performance, especially the input of different concentrations of fatty acids (especially polyunsaturated ones). Thus, here we evaluated reproductive variables in male catfish (Rhamdia quelen) of 18.45 ± 1.22 g fed with diets containing different lipid sources: fish, canola, sunflower, soybean and olive oils. 300 juvenile R. quelen were randomly distributed in 20 net-tanks (1m3) disposed inside a 200 m2 masonry pond, and the experiment was composing five treatments with four replicates, and were fed during 90 days, with a 3% inclusion level of the oils in the diets. The histological evaluations of the fish testicles were characterized in the final development stage and maturation in all animals, regardless of the offered diet. Spermatic normality, seminal volume, total sperm production, seminal pH and testosterone level did not present significant differences among treatments. Higher sperm concentration was more pronounced in males fed a diet containing sunflower oil. Parameters obtained by computer-assisted sperm analysis (CASA) showed that the poor sperm quality were verify when fish were fed diets containing olive and canola oil. The gonadosomatic, hepatosomatic and viscerosomatic fat indexes of the animals were similar, regardless of the supplied lipid source. In a practical perspective, we concluded that soybean and sunflower oils can be used as replacement to fish oil in diets for male specimens of R. quelen while the canola and olive oils should be avoid, because decrease the sperm quality.