As the perception of plant-based diets slowly shifts away from the image of a lettuce leaf on a plate, it’s no surprise to find that the popularity of this style of eating is now crossing over into meals for our canine companions.
But in a saturated pet food market, not all products are created equal, and there’s much debate over the fitness of plant-based eating for dogs.
In the first study to assess the digestibility of commercially prepared vegan pet food, researchers out of the University of Illinois tested two mildly cooked, human-grade vegan meals and a leading chicken-based kibble on a set of dogs and then measured their blood chemistry, fecal makeup, microbiome and other health-related factors.
“The trends of vegan foods and human grade foods are increasing for dogs,” said co-author Kelly Swanson, professor in the Department of Animal Sciences at the University of Illinois. “Because people are feeding these diets to their pets, it’s important they be tested like all other foods to make sure they're safe and ‘complete and balanced.'”
The two plant-based options – a high-protein grain and non-grain vegan meal from a line prepared by veterinary nutritionists – and the chicken dry food were fed to 12 healthy adult female beagles in three separate experimental periods.
The team also assessed the nutritional value of all three, finding that the vegan meals – featuring lentils, garbanzo beans, sweet potatoes, butternut squash, apples, blueberries, peas and carrots – and the kibble met the complete and balanced industry standards set by the Association of American Feed Control Officials (AAFCO).
“One thing to remember is that animals don't have ingredient requirements, they have nutrient requirements,” said Swanson. “As long as they’re consuming the essential nutrients in the correct amounts and ratios, dogs can be vegan, vegetarian, or meat-eaters.
The dogs’ stools were collected for fecal scoring and had their dry matter, pH levels, metabolite, and microbiota also assessed. The amount of poop produced was consistent across the three periods, with the plant-based offerings dishing up essential fiber.
“It’s not a surprise, really,” said Swanson. “With these ingredients, there's more fiber and oligosaccharides, which could be good for dogs that need to stay regular.”
However, the team was surprised by the readings of certain blood metabolites, molecules that circulate in the blood and can serve as health indicators. Blood triglycerides and cholesterol, which show the levels of circulating fats, were much lower when dogs were eating vegan. This suggests a plant-based diet might be beneficial for overweight animals.
When it came to gut health, the plant-based meals delivered some good news for both the dogs and their owners on poop-bag duties.
“There were some interesting and beneficial changes in the microbial community that I think reflect the blend of fibers that were present in the vegan diets,” explained Swanson. “The fecal metabolites phenol and indole, both of which contribute to fecal odor, were dramatically decreased in those diets too.
“It's still going to smell, but probably less,” he added. “Overall, it looked like there were some beneficial shifts from a gut health perspective in dogs fed the vegan diets.”
The researchers added that while these results are positive for pooches on plant-based diets, the two meal varieties used in the study were carefully formulated, and homemade dishes may not provide the same kind of “complete and balanced” diet. The cost of these readymade human-grade meals can be a prohibitive factor for families, too.
“Knowledge of ingredient composition and nutrient needs are critical, however,” warned Swanson. “Anyone can slap together a vegan meal for their dog, but without careful formulation, you might have something that's really imbalanced.”
The team would now like to compare these plant-based varieties with similar human-grade meals that contain meat, and those with and without dairy products.
“We showed that these vegan diets resulted in desirable fecal characteristics, high nutrient digestibilities, and positive changes to certain blood and fecal metabolites,” added Swanson. “For people who are interested in feeding their pets a vegan diet that aligns with their personal values, the diets we tested are a good choice.”
The study was published in the Journal of Animal Science.
Source: University of Illinois