digestibility of the polysaccharide fermented using and its improving effect on intestinal inflammation in zebrafish.

This study investigated the digestion characteristics of the polysaccharide fermented using (LA-rSFP) and its effects on dextran sulfate sodium-induced intestinal inflammation in zebrafish. The treatment substantially decreased the molecular weight of LA-rSFP and increased the reducing sugar content during gastrointestinal digestion. LA-rSFP considerably enhanced the activities of superoxide dismutase and catalase and markedly decreased malondialdehyde content, indicating a reduction in oxidative stress in the intestinal environment. Moreover, LA-rSFP ameliorated colitis-induced intestinal injury and upregulated the expression of tight junction proteins (occludin, ZO-1, and claudin-1), suggesting strengthened intestinal barrier integrity. LA-rSFP also played an important role in regulating pro-inflammatory cytokines (downregulated) and anti-inflammatory cytokines (upregulated) during inflammatory responses in the zebrafish gut. The results of 16S rRNA sequencing showed that LA-rSFP increased the diversity and richness of the intestinal microbiota in zebrafish with inflammatory bowel disease (IBD), enhancing the abundance of beneficial bacteria, such as , , , and , and reducing levels. These findings suggest that the administration of LA-rSFP alleviates IBD, with the therapeutic mechanisms partially attributed to the regulation of the intestinal microbiota composition and abundance.