Effects of enzymolytic soybean meal on growth performance, intestinal morphology, cecal microbiota, and short‑chain fatty acids in broilers

A 42‑d experiment was conducted to evaluate the effects of replacing dietary soybean meal with enzymolytic soybean meal (ESBM) on growth performance, intestinal morphology, cecal microbiota, and short‑chain fatty acids (SCFAs) in broilers. A total of 400 one‑day‑old male Cobb broilers were randomly assigned to 5 groups, each with 8 replicates of 10 birds. The control group received a corn‑soybean meal basal diet, and the four experimental groups (T1, T2, T3, T4) were fed diets in which 1 %, 2 %, 3 %, or 4 % ESBM replaced an equal amount of soybean meal, respectively. The results showed that, compared with the control group, broilers in the T3 group had a higher average daily gain (ADG) and a lower feed conversion ratio (FCR) during d 22 to 42 (P < 0.05). The T3 group also exhibited increased duodenal villus height and villus‑height‑to‑crypt‑depth ratio (P < 0.05), and a marked elevation in the relative abundance of cecal Alistipes (P < 0.05). In the T4 group, the cecal propionate concentration was significantly higher than that of the control (P < 0.05). Spearman correlation analysis revealed a positive association between the relative abundance of Alistipes and propionate concentration (P < 0.05). Collectively, these findings demonstrate that moderate inclusion of ESBM (3 %) improves late‑phase growth performance, enhances duodenal morphology, and beneficially modulates cecal microbiota and propionate production in broilers.