Interactive effects of dietary Nano selenium and vitamin E on growth, haematology, innate immune responses, antioxidant status and muscle composition of rainbow trout under high rearing density

A 60-day feeding trial was conducted to evaluate effects and interactions of dietary Nano selenium (Nano Se) and vitamin E on performance of rainbow trout under high rearing density (80 kg/m(3)). Fish (42.6 +/- 2.3 g) were stocked into 12 tanks: Control group fed basal diet and three treatment groups fed basal diet supplemented with 1 mg/kg Nano selenium (Nano Se group), 500 mg/kg vitamin E (Vit E group) and both micronutrients (Combination group). Results showed that growth, feed intake, lysozyme activity and agglutination antibody titre were significantly higher in Vit E and Combination groups. The lowest haematocrit, haemoglobin and cortisol levels and highest serum total protein and muscle crude protein were observed in Combination group. Serum globulin content was higher and albumin: globulin ratio was lower in treatment groups compared with Control. Also, the highest muscle catalase, superoxide dismutase and glutathione peroxidase activities and lowest malondialdehyde content were observed in Combination group compared with Control. In conclusion, combined supplementation of Nano Se and vitamin E provides a synergistic interaction in preventing the immunosuppressive action of oxidative stress caused by high density and significantly improved antioxidant and immune systems, health status and growth of fish under intensive culture.