Effects of grape pomace and vitamin E on performance, antioxidant status, immune response, gut morphology and histopathological responses in broiler chickens

We investigated the effects of grape pomace (GP) and vitamin E on the performance, antioxidant status, immune response, gut morphology and histopathological responses in broiler chickens. Two hundred and fifty male broiler chickens (Ross 308) were allocated to five dietary treatments (50 birds/treatment) in a completely randomized design. The experimental diets were as follows: i) Control corn-soybean meal diet (C); ii) C + Vitamin E (200 mg/kg of a-tocopherol acetate); iii) The diet containing 5% GP; iv) The diet containing 7.5% GP; v) The diet containing 10% GP. No differences were found in performance of the experimental birds. Birds fed 7.5% GP showed a significant increase in superoxide dismutase (SOD), glutathione peroxidise (GSH-Px) activity and reduced malondialdehyde (MDA) concentration. Antibody titer against Newcastle disease virus (NDV) at 42 days (d) of age in the control and 7.5% GP fed groups were lower than others. The primary IgM concentration of birds fed 10% GP was higher than the birds fed the control diet, the vitamin E supplemented diet or the diet containing 5% GP. The secondary titer against sheep red blood cells (SRBC) was increased significantly in the birds fed 10% GP and the secondary IgG concentration of birds fed 10% GP was higher than the birds fed the control diet and the diets containing 5% or 7.5% GP. In duodenum part of small intestine, villus height/crypt depth ratio and muscularis thickness were decreased. The results of the present study suggest that the inclusion of up to 10% GP in diets did not adversely affect broiler chickens' performance and improved the antioxidant and immune responses of broiler chickens.