Abstract
This study was designed to examine the effects of different levels of beta-sitosterol (BS) supplementation on growth performance, serum biochemical indices, redox status, and intestinal permeability-related parameters and morphology of young broilers. Two hundred and forty male Arbor Acres broiler chicks were allocated into 5 groups of 6 replicates with 8 birds each, and fed a basal diet supplemented with 0, 25, 50, 75, and 100 mg/kg BS for 21-d, respectively. The BS quadratically decreased feed conversion ratio during 1 to 14 d and 1 to 21 d, with its effect being more prominent at 25 or 50 mg/kg (P < 0.05). The BS linearly and quadratically reduced 14-d plasma diamine oxidase activity and D-lactate level, and this effect was more pronounced when its supplemental level was 25 or 50 mg/kg (P < 0.05). The BS linearly increased duodenal villus height (VH) and quadratically increased jejunal VH and ratio of VH and crypt depth (CD) at 14 d, and these effects in 25 mg/kg group were more remarkable (P < 0.05). Similarly, BS linearly or quadratically increased VH and ratio of VH and CD, but decreased CD in the jejunum and ileum at 21 d, with these effects being more pronounced at 50 mg/kg (P < 0.05). The BS supplementation especially at 50 or 75 mg/kg linearly or quadratically reduced 14-d serum and 21-d hepatic malondialdehyde concentration, and increased serum glutathione peroxidase and catalase activities at 14 and 21 d (P < 0.05). Moreover, the BS administration linearly and/or quadratically increased glutathione peroxidase, catalase, and superoxide dismutase activities and glutathione level, and reduced malondialdehyde accumulation in the intestinal mucosa at 14 and/or 21 d, and these consequences were more significant in 50 to 100 mg/kg BS-supplemented groups (P < 0.05). The results demonstrated that BS administration could improve growth performance, intestinal barrier function, and antioxidant status of broilers at an early age, with these effects being more pronounced at a level of 50 mg/kg.