Agaro-Oligosaccharides Modulate Gut Microbiota to Improve Lipid Metabolism in Obesity Model Rats

Obesity is a global health concern, prompting extensive research to identify food components with potential anti-obesity properties. Agaro-oligosaccharides (AOS) have been reported to have anti-obesity effects; however, the precise mechanisms underlying these effects, particularly in relation to the gut microbial metabolites, remain unclear. This study investigated the anti-obesity effects of AOS using Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an established animal model of obesity. Seven-week-old Long-Evans Tokushima Otsuka (LETO) and OLETF rats were fed a control diet or a diet supplemented with AOS for 13 wk. Blood parameters, liver lipids, and gene expression in the liver and ileum were analyzed. Bile acids were evaluated using liquid chromatography-mass spectrometry, and the cecal microbiota was analyzed using 16S rRNA sequencing. AOS supplementation suppressed body weight gain, improved metabolic parameters, and reduced hepatic triglycerides in OLETF rats. AOS supplementation altered bile acids and gut microbiota composition, increasing Akkermansia muciniphila abundance in the cecum. In addition, AOS intake downregulated the expression of lipid synthesis-related genes in the liver and ceramide synthesis-related genes in the ileum. AOS supplementation influences obesity and lipid metabolism by modulating the gut microbiota and bile acid metabolism. Therefore, AOS may help prevent various diseases by improving lipid metabolism.