Intestinal health in carnivores

The knowledge on the influence of gastro-intestinal (GI) microbiota on the health status of humans and animals is rapidly expanding. A balanced microbiome may provide multiple benefits to the host, like triggering and stimulation of the immune system, acting as a barrier against possible pathogenic micro-organism, and providing energy and nutritional support. Both culturing methods and more modern molecular techniques have provided valuable insights in gut microbiology of the dog and cat. The major bacterial phyla seem to be similar to those found in other species, with Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria, and Actinobacteria constituting more than 99% of all gut microbiota. However, the microbiota composition seems to differ substantially on a species/strain level, with much inter-individual variation. Also, studies with diseased and susceptible subjects showed clear alterations in gut microbiome, with a reduced richness of species and dysbiosis as the most commonly found deviations. Several nutritional studies have demonstrated that modulation of canine and feline gut microbiota may occur when the amounts of soluble fibres and macronutrients in the diet are changed. Interestingly, feeding a high protein, low carbohydrate diet to dogs and cats showed clear shifts in bacterial strains, which are normally associated with negative health effects in herbivorous and omnivorous mammals. However, no adverse effects of these bacterial shifts could be noticed in the dog and cat studies. The latter may indicate that species differences are indeed present, possibly driven by nutritional strategies during evolution. Further research is warranted to more thoroughly unravel the mystery of the gut microbiome in general, and that in the carnivorous dog and cat in particular.