Dietary High Fiber and N‐Carbamylglutamate Enhance Sow Reproductive Performance via Modulating <scp>Lactobacilli</scp> , Lipid Metabolites, and the <scp>PI3K</scp> ‐Akt Signaling Pathway

The aim of this study was to investigate the combined effects of a high-fiber diet supplemented with N-carbamylglutamate (NCG) (H + N) on the gut microbiota, metabolites, and transcriptome in Landrace × Yorkshire sows using a multi-omics approach. Sows were allocated to four groups in a 2 × 2 design: Low-fiber or high-fiber diets, each with or without 0.05% NCG supplementation. The H + N treatment significantly increased litter weight at weaning. Metagenomic analysis revealed H + N significantly altered gut microbiota composition and function, particularly enriching Lactobacillus at multiple taxonomic levels from order to species (including Lactobacillus sp. 910 589 175). Plasma metabolomics identified two key lipid mediators, L-α-glycerylphosphorylcholine and taurocholic acid, whose abundances were significantly elevated by H + N and positively correlated with the enriched Lactobacillus. Transcriptomic profiling showed activation of the PI3K-Akt signaling pathway in response to H + N, which was associated with observed improvement in litter weight at weaning. Collectively, the multi-omics study uncovered a novel synergistic axis wherein H + N modulated the gut microbiome (specifically Lactobacillus enrichment), which in turn shaped the lipid metabolome to activate the PI3K-Akt pathway, ultimately enhancing sow reproductive efficiency.