Sure, dogs are often said to be man’s best friend, and at times they even look like us. But it turns out that they have another rather surprising similarity – their poop.
A study in the journal Microbiome, lead by Dr Luis Pedro Coelho from the European Molecular Biology Laboratory, found that the gut microbiomes of dogs and humans actually have pretty similar genes.
“We found many similarities between the gene content of the human and dog gut microbiomes,” Dr Coelho said in a statement. “The results of this comparison suggest that we are more similar to man's best friend than we originally thought.”
In the study, the researchers evaluated the gut microbiome of two breeds of dog, beagles and retrievers. Sixty-four dogs were used in the study, which were all fed the same diet of commercially available dog food for four weeks.
The researchers then, well, collected the poop of the dogs – there were 129 poop samples in total – after four and eight weeks. They then extracted DNA from the samples to create a catalog of the dog gut microbiome, containing more than a million genes.
Comparing that to existing catalogs for humans, mice, and pigs (they didn’t have to handle their poop, fortunately), they found that the dog’s gene content was more similar to that of a human than pigs or mice were.
"These findings suggest that dogs could be a better model for nutrition studies than pigs or mice and we could potentially use data from dogs to study the impact of diet on gut microbiota in humans, and humans could be a good model to study the nutrition of dogs,” Dr Coelho said.
Speaking to Popular Science, he noted that the dog microbiome has some of the same species of bacteria as humans but different strains. So much so that their “intestinal flora could be cousins,” the site noted.
The researchers also found that the diet of humans and dogs, specifically the amount of protein and carbohydrates, had a similar effect on the microbiota of both. For example, obese dogs (half in the study were overweight) were more responsive to a high protein diet than lean dogs. Healthy microbiomes changed less, which is what you want, suggesting they are more resilient.
So remember, dogs can be sneaky little devils. But we're more similar than you thought, in a rather surprising way.