Effects of fermented wheat bran on growth performance, nutrient digestibility and intestinal microbiota of weaned piglets.

The objective of this study was to investigate the effects of fermented wheat bran (FWB) on growth performance, nutrient digestibility, serum biochemistry, short-chain fatty acids, and intestinal microbiota of weaned piglets. One hundred twenty-eight weaned piglets were randomly assigned to 4 groups, each with 8 pens and 4 piglets per pen: basal diet group (BD), 5% wheat bran group (5% WB), 5% fermented wheat bran group (5% FWB), and 10% fermented wheat bran group (10% FWB) for a 28-day trial. Results showed that compared to the BD group, the diarrhea rate in the 5% WB group was significantly increased (p < 0.05) at d 15-28 and d 1-28. In contrast, at d 15-28 and d 1-28, the diarrhea rates in the 5% FWB and 10% FWB groups were significantly lower than those in the 5% WB group and showed no significant difference compared to the BD group. Moreover, the apparent total tract digestibility (ATTD) of DM, GE, CP, EE, CF and ADF at d 1-14, and EE and NDF at d 15-28 in the 5% FWB group were significantly improved compared to the 5% WB group (p < 0.05). However, only the ATTD of CP, EE and CF at d 1-14 in the 10% FWB group were significantly higher than those in the 5% WB group (p < 0.01). Compared to the BD group, the pH of cecum chyme and serum urea nitrogen content in the 5% FWB and 10% FWB groups were significantly reduced (p < 0.05), and those in the 10% FWB group were significantly lower than those in the 5% WB group (p < 0.01). The propionic acid content of cecum chyme in the 5% FWB and 10% FWB groups, and butyric acid content in the 10% FWB group were significantly higher than those in the BD group (p < 0.05). LEfSe analysis (LDA score > 3.0) identified 4 species, 6 species of Proteobacteria, 2 species, and 9 species that were enriched in the BD, 5% WB, 5%F WB and 10%F WB groups, respectively. Additionally, Dialister, Prevotellaceae_NK3B31_group, Mitsuokella, Succinivibrio, and Prevotella were significantly and positively correlated with the concentrations of valeric acid, propionic acid, and acetic acid (p < 0.05). In conclusion, 10% FWB supplementation in weaned piglet diets did not affect growth performance, it reduced the diarrhea rate compared to the 5% WB group, potentially due to enhanced nutrient digestibility, elevated SCFAs levels, and shifts in microbial composition.