Effect of selenium on physiological and reproductive parameters in males of the catfish Sorubim cuspicaudus

Selenium is a trace mineral that participates in the body's homeostasis as an antioxidant by forming selenoproteins. In aquaculture, supplementation with this mineral influences zootechnical parameters and blood biochemistry while strengthening the immune system. This work aimed to evaluate the effect of organic selenium on physiological and zootechnical parameters in males of the catfish Sorubim cuspicaudus. Male breeders of S. cuspicaudus (n=56) with an average weight and length of 485.6 g and 39.3 cm, respectively, were distributed in 6.5 m3 pools in four treatments by triplicate. The fish were fed diets enriched with Se: 0.07 (control), 1.57, 2.07, and 2.57 mg Se/kg diet for 14 weeks. Length, weight, condition factor, and survival were recorded. In blood samples transaminases and cortisol were measured. Also, liver, kidney, and gonad histological analyses were realized. The zootechnical parameters and blood chemistry between treatments showed no significant difference (p>0.05). At the histological level, the fish fed 2.0 and 2.5 mg Se/kg diet showed moderate to severe kidney and mild liver lesions associated with selenium toxicity. The results of this study allow us to conclude that selenium doses of 2 mg or more generate toxicity in male breeders of the catfish S. cuspicaudus.