A study published in the journal, Bioscience of Microbiota, Food and Health, suggests that similar to people, dogs’ intestinal microbiota changes with age. Although there have been many studies showing that the intestinal microbiota is important for the development of the immune system and maintenance of gut health, the microbiota that makes up a healthy canine gut and how it changes with age or disease is just starting to be explored.
In this study, dogs of 5 different age groups were studied: pre-weaning (11-15 days old); weanling (6-7 weeks old); young (2 years old); aged (10-13 years old) and senile (16-17 years old).
Bifidobacteria are one type of bacteria found in people that is known to confer health benefits and these bacteria are often included in probiotic formulations, including those for dogs. In this study, bifidobacteria were found in pre-weaning and weanling puppies, but not in any of the older age groups. This is surprising and suggests that bifidobacteria may not play an important role in dog health.
Another type of bacteria often included in commercial probiotics is lactobacilli. The most common species of lactobacilli found in the dogs in this study were L. animalis and L. johnsonii. Although lactobacilli species were found in all age groups, their numbers were significantly lower in the aged and senile groups. It appears that, similar to humans, dogs’ microbiota can decrease in species number and diversity with age. It also suggests that lactobacilli may have potential as a probiotic for dogs.
So, as our knowledge of the canine microbiome increases, we may find certain probiotic species that are particularly beneficial for dogs. In the meantime, one advantage of using a prebiotic is that it favours the growth of beneficial bacteria already residing in the gut. Use of a prebiotic in aging dogs may help maintain numbers and diversity of bacteria, and therefore improve overall health.