Effects of Astragalus Polysaccharide on Growth Performance, Viscera Indexes and Antioxidant Capacity in Broilers under Oxidative Stress by Hydrocortisone Induction

This experiment was conducted to study the effects of Astragalus polysaccharide(APS) on growth performance,viscera indexes and antioxidant capacity in broilers under oxidative stress by hydrocortisone induction.Two hundred fifty-six healthy 1-day-old Arbor Acres broilers were randomly assigned to four groups with eight replicates per group and eight broilers per replicate.Control group(group A) and model group(group B) received a basal diet without APS,and experimental groups(groups C and D) received the basal diet supplemented with 0.4% and 0.8% APS,respectively.After a seven-day preliminary trial period,on day 8,20 mg/L hydrocortisone was added into the drinking water of groups except group A(drank distilled water) for 5 days;at the same time,groups C and D received the basal diet supplemented with 0.4% and 0.8% APS for 21 days,respectively.The results showed as follows: 1) adding APS in the diets improved the conditions of broiler oxidative stress,and promoted growth.The body weight at 14 days of age and average daily gain(ADG) at 1 to 14 days of age in groups C and D were significantly higher than those in groups A and B(P0.01),and the body weight at 21 days of age and ADG at 1 to 21 days of age in group D were significantly higher than those in group B(P0.05).2) Compared with group B,adding APS in the diets significantly improved the viscera indexes(spleen index in group C,thymus index in groups C and D) of the 14-day-old broilers under oxidative stress status(P0.05),but there were no effects on viscera indexes(except hepatic index in group D and spleen index in groups C and D) of the 21-day-old broilers(P0.05).3) Compared with group B,adding APS in the diets also significantly decreased hepatic malondialdehyde(MDA) content at 14 days of age and serum MDA content at 21 days of age in group D(P0.01),and promoted hepatic total superoxide dismutase(T-SOD) activity at 21 days of age in group C(P0.05).These results indicate that APS can relieve oxidative stress damage,and improve the animal growth,viscera indexes and antioxidant capacity.