Effects of Vitamin E and Selenium on Free Radicals Metabolism of Broilers

To study effects of vitamin E （VE） and selenium （Se） on dynamic variation rules, functions and metabolisms of different free radicals, 2 weeks age chicks were reared using four kinds of dietaries that differed in their VE and Se content. Free radicals in blood and tissues of broiler chicks were detected directly or indirectly using electron spin resonance （ESR） testing and biology chemistry methods. Results showed that NO free radical contents were decreasing due to the increasing of VE supplement in dietary and VE level was negatively correlated with NO free radicals. High Se supplement dietaries had the trend to induce the produce of NO free radicals. High VE and Se level dietaries significantly enhanced activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） in serum and liver. Depending on time, SOD and GSH-Px activities were declining and increasing respectively, which indicated that being short of VE and/or Se in dietaries could link to the produce of O-2, H2O2 free radicals. With the deficiency lasting, organism would continuously produce large amounts of O-2 free radicals but H2O2 free radicals were just produced explosively at the beginning of deficiency and than tended to be steady. Low VE and/or Se levels in dietaries could remarkably enhance malondialdehyde（MDA）contents in tissues and the effect of low Se was stronger. VE and Se in dietary had synergic effect on metabolisms of NO, O-2 and H2O2 free radicals.