Oat products modulate the gut microbiota and produce anti-obesity effects in obese rats

Three oat products were supplemented into high fat diets and fed to obese rats for 8 weeks. Each oat product decreased body weight, epididymal fat accumulation, and serum inflammatory factor levels and significantly regulated serum lipid levels. Oat bran significantly reduced mean adipocyte size and TNF-α mRNA expression levels. Principal components analysis showed that the oat products shifted the overall structure of gut microbiota in DIO rats. The relative abundances of Bacteroidetes and Firmicutes and the Bacteroidetes/Firmicutes ratio were altered towards that of normal rats. Spearman's correlation analysis showed that changes in the overall microbiota composition were significantly correlated with total cholesterol, triacylglycerol, endotoxin, and tumour cell necrosis factor-α levels in serum, and mRNA expression levels. Oat products significantly increased the total short-chain fatty acids (SCFA) concentration in colonic digesta. These results suggest that oat products attenuate obesity and related metabolic disorders while modifying the gut microbiota composition in high fat diet-induced obese rats.