Modulating the effects of stress induced by corticosterone injection using probiotic administration in broiler chicks

This experiment was conducted in a completely randomized design with 2×3 factorial arrangement with two levels of corticosterone injections (oil injection and corticosterone injections) and three levels of probiotic supplementation (1- without probiotic, 2 and 3- supplemented with 0.8×105 and 1.6×105 spores of Bacillus subtilis per gram of feed, respectively) to modulate stress induced by corticosterone injection using probiotic admimistration in broiler chicks. Each of 6 treatments replicated 4 times of 12birds per replicate.At 7 to 9 and 25 to 27 days of age, the chicks received one of the subcutaneous injections corn oil with/without CORT at 2 mg/kg BW twice per day. Corticosterone injection decreased the relative weight of intestine and its length at 28 and 42 days of ages (P<0.05). Relative weight of the breast was lower in corticosterone injected groups than in the oil injection groups (P<0.05). Villi height of different parts of the intestine and antibody levels against Newcastle disease decreased significantly with corticosterone injection.Adding probiotics increased the length of the villi and relative weight of the intestine. Feed to gain efficiency and average daily weight gain increased significantly in response to probiotic supplementation (P<0.05). Total coliforms and lactobacillus populations were not affected by corticosterone injections, but adding probiotic had a significant effect on ileal populations of these bacteria (P<0.05). Overall, the results of this study indicate a positive effect of probiotic on performance and intestine structure of broiler chicks under stress induced by corticosterone injection.