Probiotic powder with polysaccharides from Wolfiporia cocos alleviates antibiotic-associated diarrhea by modulating immune activities and gut microbiota.

To enhance immunomodulatory effects of lyophilized probiotics, we screened a new lyophilizing protective agent, that is Wolfiporia cocos polysaccharide (WP). This study demonstrated WP significantly increased the survival rate among seven polysaccharides, with the optimal dosage being 10 % (w/v). The ratio of bacterial suspension to lyophilizing protective agent was 1:2, in the condition, the probiotic survival rate of probiotics reached 83.06 %. Probiotic powder with WP (PWP) showed superior improvement in immune regulation and gut microbiota in antibiotic-associated diarrhea (AAD) mice compared to powder without WP. It notably increased IgM, IgG and IgA contents, and enhanced the activity of macrophage cells in the abdominal cavity. Furthermore, PWP exhibited the combined benefits of both the WP and PP in regulating the gut microbiota homeostasis, inhibiting the dysbiosis of the gut microbiota reflected in a significant increase in Proteobacteria, such as Sutterella, and decrease in Bacteroidetes, such as Muribaculaceae induced by AAD. Additionally, the correlation analysis indicated Sutterella had negative correlations with the immunomodulatory activities, meanwhile Muribaculace had positive correlations with the immunomodulatory activities. Overall, PWP could regulate the abundances of gut microbiota, thereby modulating immune activities and alleviating antibiotic-associated diarrhea, providing valuable insights for the development and application of WP in probiotics.