Multi-omics analysis identifies key microbial taxa and host genes controlling abdominal fat deposition in chickens

Abdominal fat deposition (AFD) is a complex economic trait in broilers influenced by both genetic and environmental factors, yet its underlying regulatory mechanisms remain largely elusive. To better understand this process, we analyzed a cohort of 205 chickens with phenotypic records and multi-omics datasets, including host genomics, cecal microbiota, and serum metabolomics. Using an integrative approach consisting of genome-wide association studies (GWAS), random forest, and two-part models, we dissected the individual and combined contributions of host genetics and gut microbiota to AFD. Our results identified a host gene-microbiota-metabolite regulatory axis, wherein a novel Z-chromosome gene ENSGALG00010010675 modulated the abundance of cecal Muribaculaceae. This, in turn, altered key metabolites including sorbitol 6-phosphate and gallic acid, thereby promoting AFD. Conversely, two cecal taxa-Blautia and the [Ruminococcus]_torques_group-exerted attenuating effects on AFD by regulating specific serum metabolites, such as 3-hydroxyphenylacetic acid, o-ethyl methylphosphonothioate, and 7-methylguanine. In summary, this study systematically elucidates the complex interactions among host, cecal microbiota, and metabolites underlying AFD in broilers, and identifies key microbial taxa and metabolites as potential targets for reducing excessive fat deposition.