Effects of fermented soybean meal on growth performance, antioxidant capacity and fecal microbiota of piglets.

Dry-fermented soybean meal (DFSBM) and wet-fermented soybean meal (WFSBM) were evaluated as alternatives to conventional soybean meal in piglet diets, focusing on growth performance, antioxidant function and fecal microbiome modulation. A total of 225 male piglets (Duroc × (Landrace × Yorkshire)) aged 40 days with a body weight of 13.01 ± 0.19 kg were selected and randomly assigned to three groups: control group (CON) was fed a basal diet, whereas the DFSBM and WFSBM groups received diets with 8% conventional soybean meal replaced by DFSBM and WFSBM, respectively. Results indicated that both DFSBM and WFSBM increased nutrient digestibility of crude protein and crude fat in piglets, while WFSBM enhanced serum antioxidant capacity, including elevated levels of catalase, glutathione peroxidase and total antioxidant capacity. Additionally, WFSBM reduced serum blood urea nitrogen, alkaline phosphatase and aspartate transaminase content, concurrently increasing serum immunoglobulin G levels. Analysis of 16S rRNA sequencing revealed significant differences in fecal microbiota diversity among groups, with Bacteroides, Vagococcus, Fournierella and Ruminiclostridium 9 identified as common differential genera between DFSBM/WFSBM and CON. DFSBM significantly reduced the relative abundance of Weissella, whereas WFSBM significantly increased Lactobacillus compared to DFSBM. The substitution of 8% WFSBM for conventional soybean meal exerts positive effects on animal health and fecal microbiota, with particularly noteworthy impacts on gut microbial diversity. © 2025 Society of Chemical Industry.