Effects of different levels of microencapsulated antioxidant supplementation on growth and feed performances, body composition and some blood indices in rainbow trout, <i>Oncorhynchus mykiss<I>

This study aimed to evaluate the effects of different levels of microencapsulated antioxidant supplementation (Nano-selenium, Vitamins E and C) on growth performance, body composition and some blood biochemical indices in rainbow trout, Oncorhynchus</em> mykiss</em>. Fish with an average weight of 9.07 ± 0.36 g were distributed into 12 tanks and divided into four experimental groups: treatment 1 (N-Se; 0.1, E; 30 and C; 100 mg/kg), treatment 2 (N-Se; 0.2, E; 60 and C; 200 mg/kg), treatment 3 (N-Se; 0.3, E; 90 and C; 300 mg/kg) and commercial diet as control. The results exhibited that the fish fed with diets containing additional microencapsulated antioxidant supplementation induced higher final growth, weight gain, the protein and lipid efficiency ratios, while had no different in feed conversion ratio. The body composition such as protein and lipid did not exhibit significant differences between the treatments. The serum lysozyme activity and superoxide dismutase enzyme were significantly elevated in fish fed with supplemented diet compared to the control. The alanine aminotransferase and alkaline phosphatase significantly increased in the three treatments whereas aspartate aminotransferase reduced in fish fed with antioxidant supplementation compared to the control. The present results indicated the beneficent effects of microencapsulated Nano Se and vitamins E and C on growth rate and immune response in rainbow trout.