Metagenomic analysis of vitamins B and K2 biosynthesis in chicken gut microbiota across laying periods

The gut microbiota are crucial for synthesizing vitamins vital for chicken health and production, including vitamins B and K2. However, the microbial pathways and temporal dynamics of these vitamins during different laying periods are not well understood, limiting targeted strategies to support poultry health and production. Clarifying these processes is essential for optimizing nutrition and enhancing poultry productivity. This study investigated the metagenomic landscape of microbe-driven vitamin biosynthesis with the aim of elucidating the chicken gut microbiome’s potential to produce vitamins B and K2 across various laying periods. We collected and analyzed 26,053 chicken gut genomes from diverse sources, yielding 14,121 medium-quality, non-redundant genomes for downstream analysis. Genome clustering analysis identified 2,920 species-level genome bins, predominantly from Baccetota. The gene catalog contained approximately 15.09 million non-redundant genes, of which 1.90 million were associated with the biosynthesis of vitamins B and K2. These genes were predominantly distributed among the phyla Bacillota, Bacteroidota, Pseudomonadota and Actinomycetota. Among the 14,121 non-redundant genomes, 3,453 high-quality genomes were identified as capable of de novo synthesizing at least one vitamin. Importantly, 7.67% of these genomes were capable of synthesizing five or more vitamins, while 33.85% could synthesize only one. The comparative genomic analysis of cobalamin biosynthesis underscores the dominance of the anaerobic pathway, with Bacillota emerging as a key contributor. The findings highlight the microbiome’s crucial role in vitamin biosynthesis, showing substantial taxonomic and temporal variations. This study suggests that microbial involvement plays a pivotal role in vitamin synthesis, which could inform microbiota-based nutritional strategies to support poultry health and productivity.