Multi-Omics Analysis Reveals the Hypolipidemic Effect of Dietary Fiber from Auricularia heimuer Residue

In this study, a structurally novel soluble dietary fiber (ASDF) was extracted from Auricularia heimuer residue. ASDF (340.747 kDa) is mainly composed of glucose and mannose, exhibiting a hollow globular morphology, semi-crystalline structure, and good thermal stability. In vitro, ASDF showed strong cholesterol adsorption and bile salt binding capacities (IC50 = 0.5731 and 0.5730 mg/mL), and effectively inhibited lipase, α-amylase, and α-glucosidase activities. In vivo, ASDF dose-dependently inhibited weight gain in HFD-induced obese mice and ameliorated dyslipidemia by decreasing TG, TC, AST, ALT, and LDL-C levels, while increasing HDL-C. It also alleviated hepatic steatosis by regulating the expression of SREBP-1c, FAS and CPT-1. Furthermore, 16S rRNA sequencing revealed that ASDF remodeled HFD-induced gut dysbiosis by enriching Bacteroides and norank_f__Muribaculaceae, and suppressing the overproliferation of Akkermansia and Blautia. Serum metabolomics indicated that ASDF primarily reversed abnormal metabolites by downregulating succinic acid and 20-hydroxyecdysone, and upregulating 13(S)-HODE, thereby regulating lipid metabolism, bile acid metabolism, and the PPAR signaling pathway. This study provides a theoretical basis for the high-value utilization of mushroom by-products and the development of lipid-lowering functional foods.