Home Nutrition & Formulation Vegetable Proteins Plant protein versus animal protein in petfood formulae

Plant protein versus animal protein in petfood formulae

Plant protein versus animal protein in petfood formulae
Food sources of plant based protein. Healthy diet with legumes, dried fruit, seeds, nuts and vegetables. Foods high in protein, antioxidants, vitamins and fiber.

As Jennifer Adolphe, the Nutrition Manager at Petcurean puts it: “Petfood with a higher content of plant-based ingredients provide a sustainable, ethical and environmentally friendly option for pet owners.”

This is a claim that requires further analysis, as the petfood industry begins a shift towards further inclusion of plant protein in pet diets, to substantiate existing meat-based petfood.

This includes analysing whether petfood is capable of comprising of 100 percent vegetable protein, whether this is a viable option for petfood consumers, and whether overall, plant protein is a recommended method for animal diets.

Manufacturing challenges

Current requirements for feeding pets include balanced food that needs to be nutritional, providing pets with the necessary nutrients, vitamins and proteins that they require.

Further understanding of cats and dogs’ diets are required: are they pure carnivores, or are they capable of consuming plant protein over animal?

Cats are obligate carnivores, which refers to animals whose diets must consist of at least 70 percent meat, and cannot properly digest vegetables. In contrast, a scavenger or facultative carnivore, which includes dogs, is an animal that consumes meat as its main food, although it is able to survive only on plant matter.

Dogs could exist on a properly balanced meatless diet, although most would prefer to not. Cats, however, require meat products in their diet due to their need for taurine and their inability to convert carotene to retinol.

Understanding dogs and cats’ nutritional requirements

Dogs and cats require 22 different amino acids to fulfil functions necessary to develop properly. Of these 22 amino acids, the dog can produce 12, and 10 are nutritionally essential. In the case of cats, 11 amino acids are essential.

Missing amino acids must be included in petfood, and can include:

  • Arginine: stimulates the immune system, induces the release of growth hormone and supports the liver
  • Histidine: releases histamines, is associated with pain control, and widens small blood vessels to stimulate the stomach
  • Methionine: helps the functions of the gallbladder, prevents fat deposits in the liver and balances the pH of the urinary tract

There are certain essential amino acids for dogs and cats that, very often, are not present in plant proteins, such as arginine, taurine, methionine, lysine and tryptophan.

This suggests that when considering vegetable protein for pets, you shouldn’t overlook differences between the amino acid profiles of plant and animal proteins.

It is due to these different amino acid profiles that animal protein has historically been considered ‘complete’, owing to the fact that vegetable protein (such as grain, corn gluten or soy flour) does not contain all of these amino acids necessary for the proper development and growth of a dog and/or a cat.

Advantages of plant protein

The digestibility of plant protein depends on two main factors: their source, and the processes undertaken to turn them into petfood. If they are undercooked or overcooked, this can lead to digestibility problems, but if they are handled correctly, they can be as valuable and digestible as animal protein.

Isolated soy protein, hydrolysed soy, corn gluten and wheat gluten are purified sources of highly digestible plant proteins. Wheat gluten is nearly 10 percent more digestible than beef. Therefore, an argument for plant protein is its advantage in being recommended for pets suffering from gastrointestinal problems or diseases.

Undigested proteins can overstimulate the gastrointestinal immune system, which can increase the risk of causing a food intolerance (allergy). Likewise, an undigested protein can also promote the appearance of bacteria that are harmful to the colon and the pet, as a result of the fermentation of these proteins, which triggers a strong faecal smell, flatulence and diarrhoea.

Humans suffering from liver disorders and susceptible to hepatic encephalopathy (HE) consume vegetable or dairy proteins rather than sources of meat protein, as it helps them to control symptoms. There is also evidence that similar nutritional choices for HD dogs were beneficial, given the change in blood ammonia concentration that occurs when substituting a meat protein-based diet with plant protein.

In the case of pets that suffer from EPI (exocrine pancreatic insufficiency) and skin diseases, a diet based on hydrolysed soy and rice protein is suggested specifically, since it could significantly improve their clinical condition.

Discoveries related to vegetable protein and its benefites include:

  • Soy, high in protein with an amino acid composition similar to that of meat, has been found to be more complete than previously thought
  • Wheat gluten has been found to be high in crude protein and digestible, which is why it is increasingly included in diets in Europe or the United States
  • Recently, corn gluten meal was identified as a highly digestible vegetable protein suitable for use in a canine diet


Animals will always prefer animal protein to that of plant protein. More and more owners, however, are opting for options with more and more plant ingredients, due to viewing animals as equal to one another and seeing it as a sustainable alternative that avoids the consumption of natural resources caused by meat production.

It’s important to pay attention to current trends and growing market demands, in order to be aware of products that will satisfy the market.


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