To evaluate the hypoglycemic effect of novel composite soluble dietary fiber (NCSDF) on db/db mice, and explore whether it exerts its hypoglycemic action through the gut microbiota-short-chain fatty acids(SCFAs)-glucagon-like peptide-1 (GLP-1) signaling axis.

The 8 weeks-old male db/db mice were divided into a model group, low-, medium- and high-dose NCSDF treatment groups, and a control group of db/m mice, with 10 mice in each group. After continuous administration for 8 weeks, fasting blood glucose, insulin and GLP-1 levels were measured in each group. The gut microbiota structure and metabolite levels were analyzed using 16S rRNA sequencing and SCFAs detection.

NCSDF intervention reduced fasting blood glucose levels, improved insulin resistance, and upregulated serum GLP-1 levels in db/db mice. Additionally, NCSDF intervention modulated the gut microbiota structure, increasing the abundance of SCFA-producing bacterial genera such as Bacteroides, Lachnospiraceae and Prevotellaceae, and elevated the concentrations of acetic acid, propionic acid, butyric acid, isobutyric acid and valeric acid in the intestinal content.

NCSDF may promote GLP-1 release and enhance insulin sensitivity in peripheral tissues by modulating the gut microbiota-SCFAs-GLP-1 signaling axis, thereby exerting its hypoglycemic effect.