Fermented Mao-tai lees dietary supplementation influences gut microbiota structure and activity in pigs. Fermented Mao-tai lees and gut microbiota

Gut microbiota positively contribute to the nutrition and metabolism of livestock, thus manipulation of these microbes may improve animal health. Some feed additives have been demonstrated to improve livestock health and metabolism by regulating gut microbiota composition. Here, we fed hybrid pigs with 0 (control), 5% (treat 1), 10% (treat 2), or 15% (treat 3) of fermented Mao-tai lees (FML) for 90 days. The short-chain fatty acids (SCFAs), bioamines, and microbial communities from colonic contents were analyzed to investigate the compositions and metabolic profiles of microbiota. The concentrations of straight-chain fatty acids (e.g., acetate, propionate, and butyrate) and tyramine were significantly increased with FML amount in the feed. Despite little effects of 5% FML and 10% FML on the gut microbiota, 15% FML influences the beta diversity (Jaccard or Bray-Curtis dissimilarity) but not alpha diversity (e.g., observed OTUs and Shannon diversity) of pig gut microbial communities compared with the control group. Notably, 15% FML possessed higher abundance of potential beneficial bacteria (e.g., Lactobacillus and Akkermansia) but lower abundance of potential pathogens (e.g., Escherichia). Most gene functions associated with metabolism (e.g., starch and sucrose metabolism and sulfur metabolism) were enriched in the 15% FML group. In addition, most of bacterial markers belonging to Phascolarctobacterium, Treponema, Prevotella, and Faecalibacterium in 15% FML group were positively related to the straight-chain fatty acids, indicating that these bacteria is likely to be related to these SCFAs production. Taken together, our findings demonstrated that beneficial effects of 15% FML on dietary fermentation and gut microbiota. Thus, 15% FML is the optimal additive amount for pig feed, and a new feed supplement can be developed for healthy livestock farming