Astragalus polysaccharides enhance antioxidant capacity, muscle nutrition, and metabolic health in common carp (Cyprinus carpio): associations with glucose-lipid metabolism genes and gut microbiota.

内容摘要

Astragalus polysaccharides (APS), natural bioactive compounds, enhance insulin sensitivity, suppress inflammation, and alleviate metabolic disorders. Although APS have been investigated in fish for their effects on growth, immunity, and intestinal health, their role in regulating glucose-lipid metabolism remains unclear. This study evaluated the effects of dietary APS supplementation (0.15%) in common carp (Cyprinus carpio) fed high-glucose (HG), high-fat (HF), or combined high-glucose-high-fat (HGHF) diets for 8 weeks. The HG diet primarily induced glycogen accumulation, HF diet predominantly affected growth and lipid profiles, and HGHF diet elicited combined metabolic disruption. High-energy diets significantly disrupted metabolic homeostasis, as evidenced by reduced serum high-density lipoprotein cholesterol, total antioxidant capacity, and superoxide dismutase levels, along with elevated glucose, triglyceride, and malondialdehyde levels. APS supplementation alleviated these abnormalities by reducing glycogen and lipid deposition in the hepatopancreas and muscle, attenuating hepatic vacuolation and fibrosis, and restoring intestinal morphology. APS also promoted the accumulation of essential amino acids, flavor-related amino acids, and polyunsaturated fatty acids in muscle. Molecularly, APS upregulated genes associated with glucose and lipid metabolism and partially restored microbial diversity and composition disrupted by the HGHF diet. Correlation analysis further indicated associations among beneficial bacterial taxa, enhanced antioxidant capacity, and metabolic gene expression. Collectively, APS improve antioxidant status, muscle nutritional quality, and glucose-lipid metabolic homeostasis in common carp, accompanied by alterations in metabolic genes and gut microbiota, supporting their potential as an eco-friendly feed additive in aquaculture.