Regulatory effects of ginseng polysaccharide on growth restriction and intestinal dysfunction caused by a high cottonseed meal diet in Ctenopharyngodon idella.

This study aimed to investigate the regulatory effects of ginseng polysaccharides (GP) on growth impairment and intestinal injury induced by high-cottonseed meal (CM) diets in grass carp. Juvenile fish (50.01 ± 0.13 g) were randomly assigned to four dietary groups (three replicates per group): control (CON), CM, and CM supplemented with 500 mg/kg (CMGP1) or 1000 mg/kg (CMGP2) of GP. The CM diet significantly suppressed growth and induced intestinal damage, evidenced by elevated pro-inflammatory cytokines, reduced expression of tight junction-related genes, and increased apoptosis-related gene expression. GP supplementation notably improved growth performance compared to the CM group. Additionally, GP alleviated CM-induced oxidative stress by upregulating nrf2 gene expression and downregulating keap1 gene expression. It also suppressed activation of the NF-κB/TLR signaling pathway, decreasing the expression of pro-inflammatory cytokines (e.g., tnf-α, il-1β, il-6) and increasing anti-inflammatory markers (e.g., il-10, tgf-β1). GP further modulated gut microbial composition by reducing Aeromonas and increasing Acinetobacter and Streptococcus abundances. Correlation analysis revealed a strong association between microbial modulation and improved intestinal integrity. Collectively, these findings suggest that GP can effectively counteract the negative effects of high-CM diets on growth and intestinal health through antioxidative, anti-inflammatory, and microbiota-modulating mechanisms in grass carp.