Novel approach for ameliorating high-fat diet-induced syndromes via probiotic-fermented oyster mushroom: from metabolites and microbiota to regulation mechanisms

The potential effects of probiotics on lowering lipid accumulation and alleviating gut microbiota perturbation have been extensively substantiated, but whether Lactobacillus rhamnoses-fermented oyster mushroom (FOM) could more pronouncedly attenuate obesity remains unclear. In this study, the anti-obesity effect of FOM was estimated based on the gut microbiota profile and analysis of hepatic lipid metabolic characteristics. The results revealed that FOM intervention dramatically improved hepatic lipid accumulation, characterized by reduction in fat-related factor metabolism levels and liver lesion enzymatic activities and down-regulation of the expression of genes associated with glycolipid metabolism (Foxo1, Gck, G6pd, Il6r and IL-β). Metabolomics analysis indicated HFD-induced dysglycaemia and disturbed amino acid metabolism, characterized by significant enrichment of pathways (butanoate metabolism, arginine biosynthesis, etc.) and elevated levels of d-mannose, succinate and β-d-fructose, followed by a decreased galactitol content. Furthermore, FOM intervention showed significant enrichment of specific pathways, particularly transcriptional misregulation in cancer and FoxO signaling pathways, while the MAPK signaling pathway demonstrated consistent enrichment across all experimental groups. FOM intervention reshaped the gut microbiota structure by facilitating the proliferation of SCFA producers (Romboutsia, Ruminococcaceae and Allobaculum), together with the depletion of Lachnospiraceae population. The current study strengthened our understanding of FOM prebiotic activities and obesity alleviation mechanisms.