Effects of Supplementing Yeast Fermentation Products on Growth Performance, Colonic Metabolism, and Microbiota of Pigs Challenged with Salmonella Typhimurium

Yeast fermentation products (YFPs) are known to contain bioactive compounds, such as nutritional metabolites and cell wall polysaccharides (specifically glucan and mannan), which have been demonstrated to exert positive effects on the growth performance and immunity of livestock and poultry. However, the impact of YFPs on intestinal inflammation and microflora composition in pigs infected with <i>Salmonella</i> typhimurium remains unclear. To investigate this, a total of 18 weaned pigs were divided into three treatment groups: a non-challenged control group (Con), a group challenged with <i>Salmonella</i> typhimurium (ST), and a group challenged with <i>Salmonella</i> typhimurium and supplemented with 0.4% YFP (YFP). The experiment spanned five weeks, encompassing a period of 21 days prior to and 14 days subsequent to the initial <i>Salmonella</i> typhimurium challenge. The findings indicated that the YFP group exhibited an increase in average daily gain (ADG) and a decrease in the feed-gain ratio (F/G) in comparison to the ST group following the <i>Salmonella</i> challenge. Additionally, the YFP group demonstrated a reduction in the levels of inflammatory cytokines in plasma and a decrease in the expression of inflammatory genes in the colon. Treatment with YFP also resulted in improved colon histomorphology, heightened alpha diversity of the gut microbiota, augmented the abundance of butyrate-producing bacteria, and elevated concentrations of short-chain fatty acids (SCFAs). In addition, YFP reprogrammed energy metabolism in colon epithelial cells by blunting glycolysis. Together, dietary YFP supplementation alleviated colon inflammation in weaned pigs challenged with <i>Salmonella</i> typhimurium, and shaped the beneficial microbiota, thereby maintaining gut homeostasis. The results provided evidence supporting the application of yeast fermentation products in livestock production.