title: Influence of organic zinc supplementation on the antioxidant status and immune responses of broilers challenged with Eimeria tenella.
abstract: An experiment was conducted to investigate the influence of Zn supplementation on the performance, antioxidant status, and immune responses of broilers challenged with Eimeria tenella. A total of 384 male broilers (1 d old) were assigned to 8 treatments consisting of 8 replicates of 6 chicks each. A basal corn-soybean meal diet (29.6 mg of Zn/kg) was supplemented with methionine hydroxyl analog-Zn chelate at 0, 20, 40, and 60 mg/kg of diet. At 21 d of age, birds were orally gavaged with 1.5 × 10(4) sporulated E. tenella oocysts. Dietary Zn supplementation had no effect on growth performance of either the challenged or nonchallenged birds. Activities of Cu-Zn superoxide dismutase and glutathione peroxidase were increased (P < 0.001) with increasing Zn levels in both the challenged and nonchallenged groups. Lipid peroxidation tended to be reduced (P = 0.08) at Zn inclusion of 20 and 40 mg/kg. In vitro lymphocyte proliferation responses to mitogen concanavalin A and LPS were not influenced by dietary Zn or challenge. The main effects of Zn level and challenge were significant for secretory IgA on d 28 (P < 0.01) and 35 (P < 0.001). During both periods, secretory IgA of birds receiving dietary Zn supplementation was higher (P < 0.05) than that of those receiving no Zn supplementation. Birds fed Zn supplementation excreted fewer oocysts in the excreta than those receiving no Zn supplement (P < 0.001). Results indicated that organic Zn supplementation reduced oxidative stress and improved some immune responses irrespective of whether birds were healthy or challenged with E. tenella.
authors: College of Animal Science and Technology, China Agricultural University, Beijing 100193, People's Republic of China.
authors: S D
authors: SD
authors: Bun
authors: Y M
authors: YM
authors: Guo
authors: F C
authors: FC
authors: Guo
authors: F J
authors: FJ
authors: Ji
authors: H
authors: H
authors: Cao