Multi-omics Profiling of Gut-Serum Axis Dynamics in Gestational Sows with Different Reproductive Performance

Sustainable swine production hinges on optimizing sow reproductive efficiency, yet mechanisms driving healthy litter size and weak piglet rates remain unclear. This study categorized sows into high (Group H) and low (Group L) healthy litter size groups based on median performance. Multi-omics analyses (16S rRNA sequencing, metagenomics, serum metabolomics) revealed distinct fecal microbiota and metabolic profiles between groups. The results showed significant differences in microbiota composition between groups L and H. Group H exhibited a marked increase in Bacteroidetes abundance (particularly Prevotella sp. CAG1092) concurrent with reduced Firmicutes populations. Metabolomic analysis identified 197 differentially abundant metabolites, with 85 metabolites significantly enriched in Group H. KEGG pathway enrichment analysis indicated that the differentially abundant metabolites were mainly involved in amino acid synthesis and metabolism, and multiple amino acid metabolic pathways were associated with polyamine synthesis. The correlation results showed a significant correlation (P < 0.05) between these metabolites and litter size as well as litter weight. For instance, Prevotellaceae NK3B31 abundance positively correlated with L-alanine, urea and securinine, while Prevotella sp. CAG1092 exhibited direct associations with reproductive performance. These findings suggest that gut microbiota dysbiosis may disrupt amino acid homeostasis and polyamine regulation, potentially serving as mechanistic links to reproductive efficiency. Reproductive performance dynamically shapes gut microbiota and systemic metabolism in gestating sows, with litter size influencing fecal metabolite diversity and microbial structure. This integrative analysis establishes a framework for improving both sow productivity and economic viability in pig farming.