Research Published in mBio Shows How Gut Bacteria Can Help Chubby Dogs Live a Better—& Longer—Life

As fun as it is to see Fido's face light up when you feed him table scraps, American dogs are getting fat. The good news is that research is homing in on nutritional strategies to boost canine capabilities to maintain a healthy weight.

In 2015, in a survey of 1,224 cats and dogs at 136 vet clinics, the Association for Pet Obesity Prevention found 54% of dogs and 58% of cats were obese or overweight. And there is no question that an overweight or obese pet is unhealthy. Just some of the conditions associated with too much heft in dogs and cats include:

kidney disease
osteoarthritis in hips and other joints
cancer
respiratory and heart disease
high blood pressure
type 2 diabetes and insulin resistance

Obesity in pets is death by food. While they make for funny pictures, overweight animals suffer chronic diseases and often die earlier. Unlike their humans, pets do not have a choice of food, food quantity, or the understanding of why eating all the yummy food off those plates could be bad for them.

Feeding Fido—Food Influences Doggy Gut Microbiome

As a producer of pet food, toys, cat litter, and other products, Nestlé Purina has an obvious interest in testing and developing research on pet chow. In a study just published in the journal mBio, scientists from Nestlé Purina Research explored a just-developing field of study—the microbiome of your dog.

Just like us, bacteria are omnipresent in dogs and cats, especially in the gut. While the microbiome and nutritional needs of each species are different, studies like the one from Nestlé Purina shed light on how we could better approach nutrition for our pets that could serve their bodies better.

Research Published in mBio Shows How Gut Bacteria Can Help Chubby Dogs Live a Better—& Longer—Life — Chubby dog in a hostel in Argentina. *Image by borderlys/Flickr*

The research involved 32 Labradors and 32 beagles over an eight-week period. Each breed had an equal number of dogs that were lean or overweight, and both groups were mixed male and female. The dogs were all about five years old, and paired up and housed indoors in conditions that provided social interaction, toys, and outdoor play.

For the first four weeks, the dogs were fed a commercially available diet, Purina Pro Plan Sport Active. In the last four weeks of the study, the dogs received either a high-protein, low-carbohydrate diet, or a diet low in protein and high in carbs, with portions determined by their body weight.

Scientists collected the dog poop at the end of each four week period and sequenced the genetic material of the microbes inside. The researchers were able to identify bacteria types and numbers in the microbiome of each group of dogs, and how that changed based on their diet.

Here are some of the findings:

Protein and carbohydrate ratios caused greater change in the composition of gut bacteria in overweight dogs.
The abundance of gut bacteria increased with both diets.
Dogs who ate a low-protein, high-carb diet had higher numbers of Bacteroides, a common, helpful type of bacteria responsible for breaking down complex molecules for use in the gut, but which are potentially dangerous when they become infectious in humans.
Dogs who consumed the higher protein, lower carb diet had higher numbers of Firmicutes bacteria in their gut. Firmicutes have been found to promote more complete absorption of calories, which means weight gain, in human studies.
Given the emergence of this field, and the low number of studies available for comparison, it is not clear that these observations would be applicable across the board in other dog breeds.

While animal studies with engineered mice often add to human medical knowledge, this study was specifically designed to look at native bacteria populations in dogs and how they fluctuate with different types of macronutrients. Macronutrients are major types of food, like protein, sugar, and fats. In contrast, micronutrients are vitamins and minerals needed in trace amounts to maintain health.

Researchers were careful to maintain the body weight of each dog throughout the study. Overweight dogs were fed enough food to maintain their weight—and their bacteria population—throughout the study. After the study, food quantities for overweight dogs were adjusted to help them reach a healthy weight.

A takeaway from this study is the importance of careful documentation and typing of bacteria residing in the gut of lean and overweight dogs. The research was not focused on microbiome shifts as obese dogs lost weight. The study created a baseline of differences between microbes in the guts of normal and overweight dogs to understand how "microbiological-inspired strategies" could be used to manage and perhaps eventually deter dog obesity.

In a press release, lead author in the study, Qinghong Johnny Li, notes that the results "seem(s) to suggest that obese dogs and overweight dogs are more susceptible to dietary intervention." Which is good news for our chubby friends—it means that changes in diet could impact the dog's weight.

There is hope that future studies will offer greater understanding of the interaction of bacteria, digestion, metabolism, and weight gain or loss in canines. Just as in humans, maintaining the right weight of your dog is important. The impacts of obesity on dogs can often be reversed, leading to better health and mobility.

Sharing time and space, pet owners depend on their dogs and cats in many ways. Our pets rely on us for their health and well being. No dog is "fat and happy." If you feel your pooch has got a little too much paunch, talk to your vet and learn ways to help your fur friend live a longer, more active life.