Effect of dietary Astragalus membranaceus polysaccharide on the growth performance and immunity of juvenile broilers.

This study aimed to investigate the effects of dietary Astragalus membranaceus polysaccharide (AMP) supplementation on the growth performance and immunity of juvenile broilers. High-performance liquid chromatography spectrum and sugar composition analysis indicated that AMP is a heteropolysaccharide with a molecular weight of 11,078 Da and consists of glucose, galactose, rhamnose, and arabinose. Four diets supplemented with four different levels of AMP (0, 0.5, 1, and 2 g kg-1) were formulated and tested for their effects on the growth performance and immunity of juvenile broilers. After 6 wk of feeding, the juvenile broilers fed with AMP-containing diets exhibited higher body weight gains; the activities of digestive enzymes (amylase, lipase, and protease), superoxide dismutase and glutathione peroxidase; and serum IgG, IgM, and IgA levels; and lower malondialdehyde level than the control. However, excessive AMP dose (>1 g kg-1) could not improve its efficiency further. Results indicate that dietary administration of AMP can improve the growth performance and immune responses of juvenile broilers.