Effects of different levels of dietary vitamin C on growth performance, digestive enzymes activity and blood stress factors of rainbow trout (Oncorhynchus mykiss) under sub-lethal toxicity of malathion

The aim of this study was to investigate the effects of dietary vitamin C (ascorbic acid) on growth performances, digestive enzymes activity and blood stress factors in rainbow trout affected by the toxicity of malathion in water. In this experiment, the fish were subjected to ¼ concentrations of Lc50 96h of malathion for 28 days and during this period, fish were fed with different levels of vitamin C (0, 300, 600 and 900 mg / kg of Feed). At the end of experiment, the results of the study of growth performances showed a significant increase (P0.05). Blood stress indices showed that glucose level was significantly higher in control treatment (0 m/kg) compared to other treatments and blood cortisol levels were significantly lower in the treatment of 900 mg/kg vitamin C in the diet. Finally, the results indicate that vitamin C as an anti-stress agent has been able to reduce stress in fish and improve the metabolic status and consequently the growth performance of rainbow trout.