vitamin c supplementation to rainbow trout (oncorhynchus mykiss) diet and analysis of growth indices, survival and carcass composition at two different stocking densities

background: vitamin c is one of the important nutrients in fish culture and as a potent anti-oxidant, is of great importance in preserving cells against oxidation and boosting resistance in stress conditions and against pathogens. objectives: the purpose of the present study is to add high level of vitamin c supplementation to rainbow trout (oncorhynchus mykiss) diet reared at high density and analysis of growth indices, survival and carcass composition at two different stocking densities. methods: rainbow trout juveniles with initial body weight of 9.6 ± 0.69 g at two densities of 50 and 100 pieces in 50 liters of water were fed two diets containing the same level of protein and fat. experimental diets were diet 1 without adding vitamin and diet 2 with adding 1500 mg/kg of vitamin c. a total number of 900 rainbow trout juveniles in four treatments each with three replicates as t50 (0) (with the density of 50 and fed with diet 1), t100 (0) (with the density of 100 and fed with diet 1), t50 (c) (with the density of 50 and fed with diet 2) and t100 (c) (with the density of 100 and fed with diet 2) were randomly distributed in incubators. results: after 6 weeks of feeding, growth indices, feed conversion ratio and viability were significantly different between treatments (p