Astragalus Polysaccharides Enhance Broiler Performance Through Antioxidant Modulation and Gut Health Improvement: A...

The restrictions on antibiotic growth promoters in poultry production make the exploration of safe and effective alternatives necessary. Astragalus polysaccharides (APS), as bioactive macromolecules, have attracted significant interest from poultry scientists. In the current study, a multilevel meta-analysis was conducted to quantitatively evaluate the effects of APS administration on broiler performance, antioxidant status, and gut health. The results revealed that APS supplementation significantly improved average daily gain (ADG; SMD = 0.64 [0.13, 1.15]) and feed conversion ratio (FCR; SMD = -1.20 [-2.03, -0.35]) of broilers. The observed benefits directly correlated with increased superoxide dismutase activity (SOD; SMD = 1.35 [0.78, 1.92]) and decreased malondialdehyde levels (MDA; SMD = -1.07 [-1.54, -0.60]). Subgroup analysis demonstrated that dietary supplementation was more effective than injection for improving ADG and the villus height to crypt depth ratio (VCratio), indicating the importance of direct gut-level interaction of APS. Nonlinear dose-response modelling identified an optimal dietary APS range of 1000-1500 mg/kg for maximising growth and antioxidant parameters. This meta-analysis suggests that APS shows promise as an antibiotic alternative for improving broiler growth performance, warranting further direct comparative studies with antibiotics. In addition, further large-scale trials are required to confirm its consistent efficacy on gut health and microbial composition due to substantial heterogeneity in current datasets.