Untargeted Metabolomics and Gut Microbiota Modulation Study of Fermented Brown Rice for Obesity

Obesity or excess adipose tissue mass increases the risk of heart disease, hypertension, and diabetes. Obesity might be prevented by consuming plant-based probiotic fermented foods. This study aimed to determine whether adding Pediococcus acidilactici MNL5 to fermented brown rice (FBR) enhances its metabolites, lipase activity, and antioxidant efficiency. UHPLC-Q-TOF-MS/MS analysis revealed significant changes in untargeted metabolite profiles, while, compared with those of raw brown rice (RBR), FBR contained more antioxidant and lipase inhibitors. We evaluated the FBR in HFD (high-fat-diet)-induced obese mice by employing biochemical, histological, gut microbiome, and serum metabolomics approaches. FBR MD (250 mg/kg) decreased body weight (BW) and fat content compared with RBR. With subsequent FBR MD, mice fed a HFD may have reduced serum lipid levels. A HFD with a mid-dose FBR improved the gut microbiota diversity, composition, and structure; reduced the abundance of obesity-related genera such as Helicobacter, Clostridium, and Desulfovibrio; and promoted the abundance of beneficial genera such as Bifidobacterium, Akkermansia, and Lactobacillus, which are inversely correlated with BW, total cholesterol, TG, LDL-C, and HDL-C. In addition, FBR MD has been associated with increased levels of palmitic acid, EPA, oleic acid, α-linolenic acid, indole, dodecanoic acid, and amino acids. FBR, in its entirety, has exhibited promise as a functional material for ameliorating obesity.