Introduction

An estimated 54% of dogs in the US are overweight or obese. Dysbiosis in gut microbes has been associated with obesity in humans and animal models. High-protein low-carbohydrate (HPLC) diets have been recommended for body weight management for decades, but their effects on canine gut microbiota are not well understood.

Objectives

To evaluate the effect of protein and carbohydrate ratios on gut microbiome in obese vs. lean dogs.

Methods

Sixty-three (63) Labrador retrievers and beagles, half obese or overweight (OW) and half lean or normal (LN), were fed the common baseline diet for 4 weeks, followed by 4 weeks of experimental diet: HPLC (49.4% protein, 10.9% carbohydrate) or low-protein high-carbohydrate diet (LPHC) (25.5% protein, 38.8% carbohydrate). Fecal samples collected at the end of baseline and experimental diets were subject to 16S rRNA gene sequencing analysis.

Results

Diets predominantly exerted their effects on the two phyla, Bacteroidetes and Firmicutes. The effects were greater in OW dogs than in LN dogs, but independent of breed. The HPLC-fed dogs had decreased Bacteroidetes to Firmicutes ratios, and enriched microbial gene networks associated with weight maintenance, when compared with those on LPHC. The abundance of C. hiranonis, C. perfringens, and R. gnavus were higher in the HPLC group, while B. uniformis and C. butyricum were enriched in the LPHC group.

Conclusions

This study provided an initial framework that will allow modulation of gut microbiota by nutrition interventions and may provide an alternative therapeutic option for canine obesity.