Exploring the Prebiotic Effects of Composite Fungal Polysaccharides From Hericium erinaceus and Lyophyllum decastes on Gut Microbiota and Metabolism

Fungal polysaccharides have attracted considerable scholarly interest due to their potential as prebiotics, with the ability to modulate gut microbiota and enhance host health. Despite increasing recognition, the precise effects of composite polysaccharides from various fungal species on gut microbial composition and metabolic activity remain inadequately understood. This study sought to investigate the digestibility and fermentation characteristics of composite polysaccharides derived from Lyophyllum decastes (LDUP) and Hericium erinaceus (HEUP), combined at ratios of 1:1, 1:2, and 2:1 (LDHE1_1, LDHE1_2, and LDHE2_1). In vitro simulated gastrointestinal digestion and fermentation assays were conducted to assess pH variations, short-chain fatty acid (SCFA) production, and shifts in microbial communities. The findings revealed that the LDHE1_1 formulation exhibited the most significant capacity to reduce pH and produce SCFAs, particularly propionic and butyric acids. Furthermore, the LDUP and LDHE2_1 groups favored increased acetic acid production. Importantly, these composite polysaccharides substantially enhanced gut microbial diversity, with distinct formulations promoting specific bacterial taxa. The LDUP and LDHE1_1 groups increased Firmicutes and decreased Bacteroidota, while HEUP, LDHE1_2, and LDHE2_1 groups exhibited the reverse. At the genus level, the LDHE1_1 boosted Parabacteroides, and LDHE2_1 increased Phascolarctobacterium, Akkermansia, and Oscillibacter. Both the LDUP and HEUP notably raised Alistipes levels, and all polysaccharide groups suppressed potential pathogens such as Klebsiella and Escherichia-Shigella. This study provides new insights into how specific fungal polysaccharide combinations can modulate gut microbiota composition and metabolism, contributing to the design of targeted prebiotic formulations and functional foods.