Changes of the gut microbiota and metabolite characteristics in obesity-prone and obesity-resistant dogs induced by a high-fat diet

In animals, obesity-prone (OP) and obesity-resistant (OR) typically refer to two phenotypes observed within the same strain, maintained on an identical diet. Nonetheless, investigations into the mechanisms underlying high-fat diet-induced obesity-prone and obesity-resistant phenotypes in dogs remain scarce. This study aimed to examine the interactive effects of alterations in gut microbiota and gut metabolites in dogs displaying high-fat diet-induced obesity-prone and obesity-resistant phenotypes. Forty-eight healthy dogs were randomly divided into a control group (CON) (n=12) and a high-fat diet group (HFD) (n=36). The control group received a basal diet, high-fat diet group was fed high-fat diets. After feeding a high-fat diet for eight weeks, they were divided into obesity-prone (OP) group (12) and obesity-resistant (OR) group (12) according to body weight. The 16S rDNA gene sequencing and liquid chromatography-mass spectrometry (LC-MS) were employed to investigate the distribution and interaction of gut microbiota and metabolites. Weight gain rate were significantly higher in OP and OR groups compared to the CON group, and lower in the OR group than in the OP group (p < 0.05). Gut microbiota diversity and richness varied among the three groups. The relative abundance of Fusobacteriota in the OP group was significantly greater than that in the OR and CON groups (p < 0.05). At the genus level, the number of Fusobacterium in the OP group was significantly greater than that in the other two groups (p < 0.05). Significant differences were observed in the concentration and metabolic pathways of gut metabolites between the OP and OR groups. A strong association was found between specific bacterial genera and metabolites in the canine gut. In conclusion, this study identified differences in the composition of gut microbiota and metabolites between OP and OR dogs. The manifestation of OP and OR phenotypes may be associated with abnormal metabolic processes, such as alterations in amino acid and fatty acid concentrations, as well as changes in specific gut microbiota populations.