Fermented Corn–Soybean Meal Improved Growth Performance and Reduced Diarrhea Incidence by Modulating Intestinal Barrier Function and Gut Microbiota in Weaned Piglets

This study aimed to investigate the effects of fermented corn–soybean meal mixed feed (FMF) on growth performance, intestinal barrier function, gut microbiota and short-chain fatty acids in weaned piglets. A total of 128 weaned piglets Duroc×(Landrace×Yorkshire), male, 21-day-old were randomly allocated to four groups. Piglets were fed a control diet (CON) or the control diet supplemented with 10%, 50% or 100% FMF (FMF-10, FMF-50 or FMF-100, respectively) for 14 d. The results showed that the FMF-100 group had higher average daily gain and average daily feed intake and lower diarrhea incidence than the CON group (p < 0.05). The FMF-50 and FMF-100 groups had greater villus height in the duodenum and jejunum, and the FMF-10 and FMF-100 groups had higher villus height-to-crypt depth ratio in the duodenum and jejunum than the CON group. Additionally, the FMF-100 group had higher protein expression of duodenal, jejunal and ileal ZO-1 and jejunal claudin-1; higher mRNA expression of duodenal and ileal TJP1 and jejunal CLDN1 and IL10; and lower jejunal IL1B mRNA expression (p < 0.05). The FMF-50 group showed higher jejunal ZO-1 and claudin-1 protein levels, higher mRNA expression levels of IL10 and TJP1 and lower levels of TNF in the jejunum; the FMF-10 group had higher mRNA expression levels of IL10 and lower levels of TNF in the jejunum than the CON group (p < 0.05). Furthermore, the FMF-10 and FMF-50 groups had higher colonic Lactobacillus abundance and butyrate levels; the FMF-100 group had higher abundance of colonic butyrate, Lactobacillus and Faecalibacterium than the CON group (p < 0.05). Collectively, our results suggest that FMF could improve intestinal mucosal barrier function, gut microbiota and their metabolites, thereby enhancing average daily gain and reducing diarrhea incidence in weaned piglets.