Composite Probiotic Fermented Feed Enhances Growth Performance and Intestinal Health in Weaned Piglets by Modulating the Gut Microbiome and Metabolome.

This study investigated the effects of compound microbial fermented feed on the growth performance, intestinal architecture, microbiota composition, and metabolic profiles of weaned piglets. Fifty-four weaned piglets were randomly allocated to three dietary treatment groups: a control group (basal diet), a 50% fermented feed group (T1), and a 100% fermented feed group (T2), for a 33-day feeding period. The results indicated that both T1 and T2 diets significantly improved final body weight and average daily gain (ADG), while decreasing the feed-to-gain ratio (F/G) compared with the control (p < 0.05). Morphological assessment revealed that the T1 group significantly elevated the villus height-to-crypt depth ratio in the jejunum and increased the density of goblet cells in the cecum and colon (p < 0.05). Multi-omics analysis indicated that fermented feed significantly reshaped the gut microbiota structure (p < 0.05), characterized by the enrichment of beneficial taxa, including Oscillospiraceae and Lachnospiraceae (p < 0.05), and the modulation of nucleotide and bile acid metabolism. Furthermore, correlation analysis identified significant linkages between the abundance of jejunal Oscillospiraceae and colonic/cecal Lactobacillus with growth performance, intestinal morphology, and key metabolites. This finding systematically elucidates the mechanisms by which compound microbial fermented feed promotes growth and intestinal health in weaned piglets via microbiota-mediated pathways, offering a robust scientific framework for the development of antibiotic-free nutritional strategies.