Plant based, vegan and vegetarian diets have become increasingly trendy in the human world. Whether it’s for ethical, sustainable or health reasons, a large number of people have been limiting or completely removing meat from their diet. Since our lives are so closely intertwined with our dogs, this trend of plant-based food is starting to be explored in canine nutrition as well.

Traditionally, dogs are not herbivores and have always required some form of meat to meet their nutritional requirements, specifically when it comes to protein. You may ask yourself, can my dog survive on a plant based diet? To get an honest answer, more research needs to be done. At this time, animal scientists can formulate a plant based dog food to meet a dog’s nutritional requirements. This means utilizing ingredients like chickpeas, lentils, wheat gluten, peanuts, peas, and soybeans as the primary protein source for these diets and supplementing with synthetic vitamins and minerals to meet micronutrient requirements.

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However, we must consider that just because we can formulate to meet requirements, it does not mean that dogs can necessarily digest and absorb those nutrients. This is where the measurement of digestibility comes into play. Digestibility refers to the amount of a specific nutrient absorbed by a dog. It is calculated as the amount of nutrient consumed minus the amount of nutrient retained in the feces. Ultimately, while we can formulate sufficient plant based nutrients in dog food, plant products may not be digestible enough to dogs for them to adequately digest and absorb all of the required nutrients in a plant based diet. This is because plants contain different factors like indigestible fibre and antinutritional factors which can significantly lower nutrient digestion and accessibility.

A 2019 study by the University of Guelph aimed to answer this question by examining the digestibility of macro and micro minerals in both animal and vegetable based pet food.

What they did

To complete the study, 8 research beagles were fed either an animal based or vegetable based diet that was house formulated to meet the nutritional requirements for adult maintenance. 2 additional diluted diets were also fed to the dogs to measure endogenous mineral loss. The diluted diets were created by diluting the animal and vegetable based diets with anhydrous α-d-glucose.The dogs were fed the diets randomly for 10 days, with fecal samples being collected on the last 4 days of feeding.

What they found

The first finding of the study was that the non-diluted diets had a higher apparent mineral digestibility compared to dogs fed diluted diets. Following that, apparent phosphorus digestibility was higher for dogs fed the vegetable based diet compared with the animal based diet. Furthermore, Copper, Phosphorus, Magnesium, Zinc, and Manganese true digestibilities were also higher for dogs fed the vegetable based diet compared with the animal based diet. 

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Take home message

The use of plant based diets in pet food is still in its infancy. However, this study has shown that when it comes to minerals, both animal and vegetable based ingredient diets can supply the required minerals for adult dogs. Apparent digestibility results also demonstrated that a vegetable based diet can match or exceed the digestibility of mineral nutrients when compared with an animal based ingredient diet.

As always further research is needed to explore the potential of commercial plant based dog food, especially when it comes to nutrients like amino acids and fatty acids. However, this study shows that plant based diets are digestible and adequate when it comes to macro and micro minerals.