Assessment of vitamin C effect on body composition and some antioxidant enzyme activities in Caspian brown trout fry (Salmo trutta caspius)

In order to study of vitamin C effect on body composition and antioxidant enzyme activities, including superoxide dismutase and catalase in five diets containing different levels of vitamin C (0, 50, 250, 750and 1500mg vitamin/kg diet) had been fed by Caspian brown trout fry (Salmo trutta caspius) for 6 weeks in triplicate. After 6 weeks, the findings of growth parameters and survival showed significant difference among groups (P< 0.05). The lowest amount of SGR, BWG and survival was observed in control group while the group of 750 mg/kg had the highest amount of SGR, BWG and survival than those from others. The vitamin C concentration in tissue correlated positively with increasing its levels in diets. The vitamin C requirements were estimated to be 569.1 mg kg-1 based on body weight gain. Body composition including moisture, ash, fat and protein showed no significant difference among groups (P>0/05). The effect of confinement stress on antioxidant enzymes activity of control diet was indicated a sigtnificat increase in activity after stress than that from before sttress (P < 0.05), While other diets showed no significatnt diference between pre-stress and after stress (P > 0.05). The findings suggest that the 750 mg/kg vitamin C could be affected on growth and survival in caspian brown trout fty.