Effects of Lipoic Acid on Immune Function, the Antioxidant Defense System, and Inflammation-Related Genes Expression of Broiler Chickens Fed Aflatoxin Contaminated Diets

This study was designed to evaluate the effect of low level of Aflatoxin B-1 (AFB(1)) on oxidative stress, immune reaction and inflammation response and the possible ameliorating effects of dietary alpha-lipoic acid (alpha-LA) in broilers. Birds were randomly allocated into three groups and assigned to receive different diets: basal diet, diet containing 74 mu g/kg AFB(1), and 300 mg/kg alpha-LA supplementation in diet containing 74 mu g/kg AFB(1) for three weeks. The results showed that the serum levels of malondialdehyde, tumor necrosis factor alpha (TNF alpha) and interferon gamma (IFN gamma) in the AFB(1)-treated group were significantly increased than the control group. In addition, the increased expressions of interleukin 6 (IL6), TNF alpha and IFN gamma were observed in birds exposed to the AFB(1)-contaminated diet. These degenerative changes were inhibited by alpha-LA-supplement. The activities of total superoxide dismutase and glutathione peroxidase, the levels of humoral immunity, and the expressions of nuclear factor-kappa B p65 and heme oxygenase-1, however, were not affected by AFB(1). The results suggest that alpha-LA alleviates AFB(1) induced oxidative stress and immune changes and modulates the inflammatory response at least partly through changes in the expression of proinflammatory cytokines of spleen such as IL6 and TNF alpha in broiler chickens.