Although scientists have investigated extensively the microbiomes of dogs, until recently most studies have been limited to domestic dogs. In a new study led by the University of Illinois, Urbana–Champaign, experts have sampled the fecal microbiomes of dogs across diverse geographical populations to better understand their diversity around the world. Surprisingly, they discovered that, although the microbiomes across different populations differed in certain aspects, they were functionally similar.
“A lot of the studies look at how different diets affect dog microbiomes. Although they are extensive, they work with dogs in veterinary centers, which lead a very different life from dogs that don’t live as pets,” said study lead author Karthik Yarlagadda, a doctoral student in Biological Anthropology at the University of Illinois. “It’s similar to how studies on the microbiomes of humans have been focused on people who live in cities and eat processed foods.”
Together with his colleagues, Yarlagadda collected fecal matter from three different dog populations: pets from South Africa, stray and shelter dogs in India, and dogs from a rural village in Laos. In each of these locations, dogs had different diets. While the shelter dogs were fed rice, lentils, yoghurt, and dog food, village dogs consumed local agricultural products, such as maize, bamboo, sticky rice, and fish, and stray dogs likely scavenged on human leftovers.
Interestingly, although the scientists found several differences between the microbiomes of these populations, functionally they appeared to be quite similar. “It was cool to see that you can have different microbiomes, but they all fulfil the same metabolic function. For example, dogs that were consuming dairy in the South African and Indian populations had different Lactobacillus species that were probably involved in the same pathway,” Yarlagadda explained.
Besides comparing the microbiomes of dogs from different geographical locations, the researchers also contrasted samples from ancient microbiomes, obtained from fossilized dog feces. These microbiomes were more similar to those of dogs that lived in an outdoor environment and had mixed diets and more environmental exposures.
In future research, the scientists aim to find more data on ancient microbiomes in various dog species, and investigate how different diets influenced the composition of their microbiomes.
The study is published in the journal Proceedings of the Royal Society B: Biological Sciences.