We measured plasma concentrations of malondialdehyde (MDA) as indices of the levels of lipid peroxidation products. In addition, we studied the activities of the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), in broiler chickens infected with Eimeria tenella and treated with a combination of Cygro® (1% maduramycin ammonium) and vitamin E. Before treatment with this drug combination there were significantly higher levels of MDA, decreased SOD and increased CAT erythrocyte activities in the infected chickens compared to the healthy controls (P<0.001). Treatment with Cygro® alone showed some beneficial effects on lipid peroxidation in broiler chickens infected with Eimeria tenella. However, a combination of Cygro® (5 ppm) and vitamin E, at a dose 50 mg per chicken for 11 days, did not attenuate oxidative stress (increased plasma MDA) and did not normalize the ecological oxidative balance (EOB) in the chickens (decreased SOD and increased CAT). The observed changes in the economical parameters (weight gain and FCR) were indicative for a severe infection, in which the oxidative stress probably was also involved during pathogenesis.
N. Georgieva, V. Koinarski, M. Gabrashanska