Effects of fermented mulberry leaves on growth performance, nutrient digestibility, diarrhea, and intestinal microecology in weaned piglets: a preliminary study

This study investigated the effects of dietary fermented mulberry leaves (FML) on growth metrics, nutrient digestibility, diarrhea incidence, and gut microbial ecology in weaned piglets. A total of 200 piglets (28 days old) were randomly allocated into five groups: a basal diet control group and four treatment groups receiving the basal diet supplemented with 5%, 10%, 15%, or 20% FML (co-fermented with Lactobacillus and cellulase) over a 28-day period. Growth performance, apparent nutrient digestibility, diarrhea rate, intestinal pH, short-chain fatty acid (SCFA) concentrations, and cecal microbiota (via 16S rRNA sequencing) were evaluated. No notable differences in growth performance were detected across groups ( P > 0.05); however, the feed-to-gain ratio was significantly lower in the 5% and 20% FML groups ( P < 0.05). Diarrhea incidence declined across all FML-supplemented groups, with the greatest reduction (52.46%) in the 15% group during days 28–42. Duodenal pH decreased significantly in all treatment groups ( P < 0.05). Cecal acetate and propionate levels rose markedly in the 10%, 15%, and 20% groups ( P < 0.05), with the 15% group showing a 47.05% increase in acetate. FML supplementation also altered cecal microbial diversity and community composition. At the genus level, the 15% group had the highest relative abundance of Prevotella (22.46%), while Lactobacillus and Bifidobacterium tended to increase in FML groups. Overall, dietary inclusion of 5–20% FML did not significantly enhance growth performance but effectively reduced diarrhea, optimized intestinal pH, increased cecal acetate and propionate production, and modulated cecal microbiota composition, with 15% FML identified as the optimal level.