Sargassum fusiforme and its fucoidan alleviates high-fat diet induced obesity associated with the improvement of the gut microbiota profile

Obesity is considered a significant global health issue. The gut microbiota plays a crucial role in preventing obesity. Sargassum fusiforme and its fucoidan extract have lipid-lowering effects, but their mechanisms are not yet fully understood. This study investigates the mechanisms by exploring changes in gut microbiota composition, gene expression, and metabolites in mice fed a high-fat diet after intervention with Sargassum fusiforme (SF) and Sargassum fusiforme fucoidan (SFF) through integration of 16S rRNA sequencing, transcriptomics, and non-targeted metabolomics. Our results demonstrate that Sargassum fusiforme can ameliorate high-fat diet-induced obesity by decreasing the abundance of specific Firmicutes phylum bacteria, reducing the levels of glycochenodeoxycholic acid, glycoursodeoxycholic acid, glycohyodeoxycholic acid, and glycodeoxycholic acid, and regulating the expression of the Elovl3, Gm3734, Per2, and Tnnc1 genes. This offers a new perspective for hypercholesterolemia treatment strategies. • Sargassum fusiforme and Sargassum fusiforme fucoidan can reduce fat accumulation caused by high fat feeding. • Sargassum fusiforme fucoidan can optimize the structure of intestinal flora and improve the disorders caused by high fat diet. • Sargassum fusiforme and Sargassum fusiforme fucoidan can reduce the abundance of Firmicutes, increase SCFAs, and promote bile acid reabsorption • Sargassum fusiforme and Sargassum fusiforme fucoidan interfere with fat synthesis by regulating the expression of Elovl3 and Per2 genes.