Effects of yeast-derived postbiotic in different energy diets on growth performance, immunity, antioxidant status, and intestinal microbiota in growing pigs

To explore the impacts of yeast-derived postbiotic on growth performance and intestinal microbiota of growing pigs, 192 healthy Duroc × Landrace × Yorkshire (initial weights 30 ± 0.6 kg) were subjected to four dietary treatments, with eight replicates per treatment and six pigs per replicate. The diets were: CON: basal diets; YC: CON with 0.5 g/kg yeast-derived postbiotic; RED75–: CON with net energy reduced by 75 kcal/kg; RED75+: RED75– with 0.5 g/kg yeast-derived postbiotic. The results showed that yeast supplementation improved average daily gain in the low energy dietary treatments, tended to improve nutrient digestibility and feed conversion rate. Yeast supplementation in normal energy diets decreased the levels of serum inflammatory factors including IL-1β, IL-10, TNF-α, IFN-γ, and IgA. Yeast in low-energy diets improved antioxidant status by decreasing serum MDA and increasing GSH-Px. Yeast significantly reduced α diversity of the pig feces. Compared to RED75–, Lactobacillus, Faecalibacterium, and Blautia were more prevalent in RED75+, at the family level Christensenellaceae, Rikenellaceae, and inflammatory-related Prevotellaceae were lower in RED75+, the abundance of fiber-digesting bacteria Megaphaera, Subdoligranulum, and Coprococcus were higher in RED75+. Correlation analysis revealed that altered bacterial composition involved glucose/mannose/galactose/fructose metabolism. In vitro, yeast-derived postbiotics promoted the growth of L. amylovorus, L. johnsonii, and L. reuteris at different pH. Our findings provide evidence that supplementation of yeast-derived postbiotics is beneficial to growth performance, anti-inflammatory, antioxidant status, and intestinal microbiota composition of growing pigs by promoting the growth of Lactobacillus.