Abstract
IMPORTANCE: The composition of the gut microbiota is essential for a dog's health and its adaptation to the environment. Different bacteria can produce the same essential metabolites beneficial to health owing to bacterial functional redundancy in microbial communities. OBJECTIVE: This study examined the gut bacterial communities of dogs from different breeds, all kept under identical domestication conditions. METHODS: Noninvasive sampling and 16S rRNA high-throughput sequencing were used to compare the composition and function of the gut microbiota of three dog breeds: the Chinese Kunming dog (CKD), German Shepherd dog (GSD), and Belgian Malinois dog (BMD). RESULTS: The gut microbiota of the three dog breeds consisted of 257 species across 146 genera, 60 families, 35 orders, 15 classes, and 10 phyla. The dominant bacterial phyla across the three breeds were Firmicutes (57.44%), Fusobacteriota (28.86%), and Bacteroidota (7.63%), while the dominant bacterial genera across the three breeds were Peptostreptococcus (21.08%), Fusobacterium (18.50%), Lactobacillus (12.37%), and Cetobacter (10.29%). Further analysis revealed significant differences in the intestinal flora of the three breeds at the phylum and genus levels. The intestinal flora of BMD was significantly richer than that of CKD and GSD. The functional prediction and Kyoto Encyclopedia of Genes and Genomes analysis showed that the primary functions of the gut microbiota in these breeds were similar, with significant enrichment in various metabolic pathways, including carbohydrate and amino acid metabolism, secondary metabolite biosynthesis, and microbial metabolism in different environments. The intestinal flora of these breeds also played a crucial role in genetic information processing, including transcription, translation, replication, and material transport. CONCLUSIONS AND RELEVANCE: These results provide novel insights into the intestinal flora of intervention dogs and suggest novel methods to improve their health status, which help increase microbial diversity and normalize metabolite production in diseased dogs.