Genome-resolved and culture-based atlas of the feline gut microbiome enables host-adapted probiotic development

Domestic cats (Felis catus) depend on their gut microbiome for metabolism, immunity, and pathogen defense, yet its genomic characterization remains limited. We combined large-scale metagenomics and culturomics to define the feline gut microbiome and identify indigenous probiotic candidates. Analysis of 412 feline fecal metagenomes produced 2852 strain-resolved metagenome-assembled genomes (MAGs) grouped into 514 species-level genome bins, including 106 putative novel taxa. This catalog revealed 24 core species and two enterotypes: ET-P, deaminated by Prevotella, and ET-CB, enriched for Collinsella, Blautia, Bifidobacterium, Ligilactobacillus, MAG-based screening prioritized 113 candidate probiotic species. Culturomics recovered 2904 isolates representing 110 species-level taxa, including 75 putative novel species and a candidate novel genus. Six feline-derived isolates were selected for downstream testing, and five exhibited favorable probiotic traits in vitro, including acid and bile tolerance, anti-Escherichia coli activity, and favorable cytokine responses. In a pathogenic Escherichia coli-induced dirrhea model in cats, a five-strain indigenous consortium improved fecal scores and reduced IL-2, IL-1β, and IL-6, with TNF-α suppression superior to antibiotics or a commercial probiotic. These results establish FelMGDB as a resource for feline microbiome research and highlights indigenous probiotics as promising interventions for feline gut health.