This study investigated the effect of feeding vitamin E, vitamin C, and two sources of vegetable oil on immune response and meat quality of broilers. A total of 320 one-day-old chicks were used in a completely randomised design with eight treatments arranged as a 2 × 2 × 2 factorial with two levels of vitamin E (0 and 200 mg/kg), two levels of vitamin C (0 and 1000 mg/kg), and two sources of vegetable oil (soybean and canola). Dietary supplementation of either vitamin E or C increased (P < 0.05) secondary humoral response, whereas oil sources had no significant effect. Broilers fed soybean oil had lower cellular response to the phytohemagglutinin skin test than those fed canola oil in diet, and supplementation of vitamin E increased cellular immune response. However, fat, cholesterol and pH of meat were not affected by source of oil or antioxidants, lipid oxidation was higher (P < 0.05) in thigh and breast meat of broilers fed soybean oil than canola oil. Dietary supplementation of vitamin E decreased (P < 0.05) lipid oxidation in thigh and breast of broilers fed diet containing soybean oil, without any effect on meat oxidation of those fed canola oil. Dietary supplementation of vitamin C increased lipid oxidation in thigh meat of broilers (P < 0.05). It can be concluded that inclusion of soybean oil to the diet, compared with canola oil, increased need for antioxidant. Vitamin E had beneficial effects on immune response and reduced meat lipid oxidation; nonetheless future studies should explore the antioxidant effect of vitamin C in stored meat.
An excess dietary vitamin E concentration does not influence Nrf2 signaling in the liver of rats fed either soybean oil or salmon oil
