Diarrhea in piglets causes intestinal inflammation and epithelial damage. Weaned piglets fed with Bacillus subtilis (B.S) have enhanced intestinal mucosal immunity and reduces diarrhea in piglets. However, the immune system of newborn piglets is immature, and B.S cannot effectively activate the intestinal mucosal reaction when given directly. This research explored the impact of the maternal supplementation of B.S-Dia during the final 35 days of gestation on piglet intestinal development and mucosal immunity. The results demonstrated that B.S-Dia administration significantly increased the body weight, jejunal villus height, and crypt depth in the piglets. In addition, B.S-Dia also significantly increased the proliferative activity of intestinal epithelial cells, as evidenced by proliferating cell nuclear antigen (PCNA) staining and the elevated mRNA expression of the proliferation-related gene (c-Myc). Furthermore, B.S-Dia supplementation also reinforced the intestinal mucosal barrier by increasing goblet cell numbers and upregulating the mRNA expression of antimicrobial peptides, such as Muc2 and Lyz-1. Finally, elevated levels of IL-4 and IFN-γ, along with an increased abundance of CD3⁺ T cells, revealed that the intestinal mucosal immunity of piglets was improved after B.S-Dia administration. Our study indicates that feeding B.S-Dia to sow spromotes intestinal development and improves intestinal mucosal immunity in piglets.

Schisandra chinensis polysaccharides (SCP) are isolated from Schisandra chinensis with a mean molecular weight of 32.401 kDa. Previous studies have demonstrated that Schisandra chinensis extract effectively prevented colitis and modulated gut microbiota in dextran sulfate sodium (DSS)-induced mice. In this study, 3% DSS was used to induce acute ulcerative colitis in mice, and then the SCP with different doses (50 mg/kg, 100 mg/kg, 200 mg/kg) and 5- aminosalicylic acid (5-ASA) were used to treat mice by oral gavage for one week. Here, we report for the first time that SCP presents outstanding protective effects on colon damage induced by DSS in mice. Firstly, SCP decreased oxidative stress, downregulated the expression of inflammatory factors, and inhibited the TLR4/p65/IκBα pathway in the colon. Then, SCP reversed DSS-induced intestinal barrier damage by improving the tight junction proteins. Moreover, SCP improved the levels of SCFA in the intestine of mice. Furthermore, SCP increased the diversity of gut microbiota and the abundance of beneficial bacteria, especially Lactobacillus and Akkermansia. Our results indicated that the protective effect of SCP on colitis caused by DSS may be due to inhibiting the TLR4/p65/IκBα pathway and the regulation of gut microbiota.