Impact of Foods on The Gastrointestinal Microbiome of Obese Dogs During Weight Loss

Abstract

ObjectivesThe relationship between gut microbiome and obesity is known; this study focused on gut microbiome changes during weight loss in obese dogs fed three different foods MethodsControl and two test foods formulated with a mean of 3153 kcals/kg SD ± 107.8. All foods were similar in their as fed protein (30.7% SD ± 0.73), carbohydrate (32.0% ±1.25) and fat (11.7% ±0.86) levels but differed in crude fiber (CF), total dietary fiber (TDF) and n-3FAs. Soluble: insoluble fiber (SF: IF) and n-3FAs: n-6FAs ratio were 0.13 and 0.07 in control and 0.27 and 0.62 in test foods. The study used 22 healthy adult dogs except their obese condition with a fat mass of >37% in a cross-over design. Control food was fed in pre-feed (28d) and washout period (28d) and two test foods were fed during treatment phases (phase 1 and 2, 56d each). All dogs were fed based on their body weight. DEXA was performed at the end of pre-feed, phase 1 and phase 2. Fecal samples were collected at the end of pre-feed, phase 1, washout, and phase 2. The study was approved by IACUC and dogs were allowed regular socializing. Fecal microbiome was analyzed by 16S rRNA amplicon sequencing using V3-V4 regions. Data analysis was performed using JMP v15.0. Variables with significance at P < 0.05 are reported. ResultsAll foods resulted in weight loss. Microbiome analysis showed differences between dogs fed control and test foods, but no differences were observed between test foods. Bacteroidetes (B), Fusobacteria increased and Firmicutes (F) decreased in test compared to control food. Diversity, evenness and B: F ratio increased in test compared to control food. Genera, Bacteroides, Fusobacterium, Faecalibacterium, and Lachnospira increased and Clostridium, Blautia, Dorea, Peptococcus and Turicibacter decreased in test compared to control food. Regression analyses show Blautia and Clostridium have inverse (R2 0.10) and Fusobacterium has positive (R2 0.09) correlation with total lean mass. The intakes (g/kg BW0.75) of SF and n-3FAs show positive (R2 0.10 and 0.19) correlation to Fusobacterium and inverse (R2 0.12 and 0.10) correlation to total fat mass. ConclusionsThis study shows that gut microbiome of obese dogs significantly changes during weight loss. SF and n-3FAs levels have potential roles in weight loss with gut microbiome changes. Funding SourcesHill’s Pet Nutrition, Inc.