Vitamins and nutrients are of those antioxidant agents that play a significant role in preventing oxidative stress and inhibiting radicals. The present study aimed at investigate the levels of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC) and lipid peroxidation (MDA) in the blood serum of rainbow trout fed with vitamin E,selenium and vitamin C supplements. One hundred eighty pieces of rainbow trout with an average weight and length of 121 ±18 g and 22/92±1/65 cm, respectively, in four groups of 15 numeric in triplicate, including the control, V_C300 (300 mg per kg of diet), V_C1000 (1000 mg per kg of diet), V_ESe (Se 0/5 and E 100 mg per kg of diet) were divided in the 300-liter fiberglass tanks, and the diet was considered equivalent to 2% of their body weight. Then, sampling and enzyme measuring was performed on days 14 and 28 after experiment initiation. SOD and CAT activities was significantly decreased after 14 days in groups of V_C1000 and V_ESe compared to control  but after 28 days showed a significant increase (P<0.05). Also, TAC levels of treatments VC1000 and VESe were significantly increased in the two-stage sampling. In addition, MAD index was significantly reduced in VESe , but  VC1000 was not significantly different from the control group. However, there was no significant difference between the control group and VC300 of MDA and TAC parameters. The carried out measurements revealed that addition of  VESe and C to the diet as a non-enzymatic antioxidant agents can act in line with antioxidant enzyme agents and cause modulating the activity of antioxidant enzymes, increasing levels of total antioxidants and reducing the destructive process of lipid peroxidation. Generally, fish treated with vitamin E and selenium has higher antioxidant capability than the fish treated with vitamin C. These days, regarding the possibility of a wide range of contaminants in water used for breeding as oxidative factors, knowing how to use these supplements to the diet with regard to the appropriate dosage and use, in order to increase the antioxidant defense and oxidative stress seems to be useful and necessary to prevent damages