Dietary Vitamin E Influences the Levels of Nitric Oxide and Cytokines in Broiler Chickens

The study investigated the effects of dietary Vitamin E (VE) on nitric oxide (NO) metabolism, immune function and analyzed the correlation between NO free radical and cytokines (IL-2 and IL-6) in broilers. One hundred and fifty 2-week-old broilers were randomly divided into three groups. Control group and lower VE (VE) group were provided with a basic diet supplemented with 12.55 mg/kg VE and 2.55 mg/kg VE for 30 days, respectively. Higher VE (VE-VE) group was supplemented with 2.55 mg/kg VE in the first 15 days and then 32.55 mg/kg VE in the next 15 days. Five broilers in each group were then sacrificed on the 5th, 10th, 15th, 20th, 25th and 30th days, respectively, and the content of NO free radical, superoxide dismutase (SOD), glutathione peroxidase (GSHPx), malondialdehyde (MDA) and cytokines, IL-2 and IL-6, were measured. The results showed that lower VE could decrease growth performance of broilers while higher VE could increase growth performance and eliminate differences resulted from feeding lower VE dietary in early stages (p<0.05). Compared with the control group, lower VE could increase significantly NO and MDA concentration, and increase IL-2 concentration in serum (p<0.05). Higher VE could significantly increase activities of SOD and glutathione GSH-Px (p<0.05). IL-2 is positively correlated with NO in heart (p<0.05) and IL-6 is negatively correlated with NO in liver (p<0.05) and heart (p<0.01). These results indicate that dietary VE could regulate antioxidant capacity and NO metabolism of broilers and higher VEsupplemented diet could directly decrease production of IL-2. (