Dietary manipulation of canine and feline gut microbiome

Abstract Text:

Dogs and cats evolved as Carnivora and have traditionally relied on high-protein, high-fat diets containing relatively low fiber concentrations.  Despite having a simple gastrointestinal tract designed to digest such diets, a rich microbial community exists.  Today’s pet dogs and cats live in close proximity to humans and have similar environmental exposures, serving as potential vectors for pathogen exposure.  Dogs and cats are also afflicted by many of the complex diseases present in humans, including obesity, diabetes, inflammatory bowel diseases, and cancers, all of which may be influenced by diet and the gut microbiota.  Given their proximity to humans, similar disease incidence and etiology, and unique metabolism, microbiome research in dogs and cats may not only lead to improved pet nutrition and veterinary care, but may increase our understanding of host-microbe interactions, with relevance to human metabolism and diseases and public health at large.  Molecular techniques, including high-throughput sequencing, have dramatically changed the research landscape in regards to gastrointestinal microbiology.  These techniques have been used to characterize the phylogeny and functional capacity of the canine and feline gastrointestinal microbiota and identify the effects of diet, age, and disease on these communities.  Several hundred bacterial phylotypes, predominated by members of Firmicutes, Fusobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, are now known to inhabit the dog and cat gastrointestinal tract.  Recent studies have revealed that the functional capacity of the gastrointestinal microbiota in dogs and cats is quite broad and similar to that of humans and rodent models.  Although these populations are quite stable over time, our laboratory has demonstrated that macronutrient profile (e.g., dietary protein: carbohydrate ratio), dietary fiber amount and type, and the form of food consumed (e.g., raw vs. extruded diets) may have dramatic effects on the gastrointestinal microbiome of these host species.  These dietary changes have not only been reported to impact microbial diversity and richness, gene content, and metabolic activity, but to alter host physiology and metabolism as well.  Unfortunately, the majority of research has been performed in healthy animals housed in research colonies rather than free living pets.  Continued research on the composition and activity of the canine and feline gastrointestinal microbiomes, and how they are impacted by dietary intervention and other environmental exposures, is needed to increase our understanding of the host-microbe interactions that occur in the gastrointestinal health and their relevance to health and disease.   

Keywords: canine nutrition; feline nutrition; gut microbiota