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Protein Digestibility in Dogs – Definition, Bioavailability, Amino Acids & Consequences

↯ Key takeaway points

  • Digestibility of proteins in dogs is not a required label on pet food packaging.
  • Bioavailability of amino acids influences the production of hormones and neurotransmitters.
  • Popular dog food brands average 81% protein digestibility, with the minimum target being 80%.
  • Lamb, chicken, and beef are the most digestible meats for dogs.
  • Canine nutritionists offer dietary advice and diet-based treatments for dogs.
Written by Jay
BsC (Hons) Animal Behaviour & Welfare graduate with a passion for advocating for misunderstood animals.
Zoo and wildlife doctor in veterinary medicine passionate about animal welfare and preventive medicine.
Published on
Thursday 11 June 2020
Last updated on
Wednesday 24 May 2023
protein digestibility in dogs
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Digestibility simply refers to the percentage of nutrients that a dog’s body is able to absorb during the process of digestion.

While protein digestibility isn’t always listed on pet food labels, it’s crucial to be aware of which proteins are most suitable for your furry friend, particularly if your dog has sensitivities to certain types of proteins.

So, if you’re a pet owner, it’s worth knowing that the digestibility of proteins can impact your dog’s overall health and well-being. By choosing the right protein sources for your pup, you can help ensure they get the nutrients they need to thrive.

Bioavailability of Proteins in Dogs

Proteins are large molecules made up of 20 amino acids. While dogs produce about half of these amino acids themselves, the other half, called essential amino acids, must be provided through the diet.

The ten essential amino acids for dogs are:

  1. Arginine
  2. Isoleucine
  3. Leucine
  4. Lysine
  5. Methionine
  6. Threonine
  7. Tryptophan
  8. Histidine
  9. Phenylalanine
  10. Valine

One of the biggest demands for protein digestibility in dogs is in the maintenance of fur growth. The process uses up to 30% of a dog’s daily protein intake. Bioavailability of amino acids influences the production of hormones as well as neurotransmitters which affect a dog’s behavior. Amino acid deficiencies result in a range of debilitating disease states. These include decreased immunity, nutritional deficiencies, fatigue, and even premature death.

Protein Digestibility of Commercial Dog Foods

Digestibility refers to the relative amount of nutrients within the diet that become available to the body after digestion and absorption. The protein digestibility in dogs for a food product is determined through feeding trials, as described by the Association of American Feed Control Officials (AAFCO).

Digestibility of a nutrient is calculated by finding the daily amount of food consumed minus the amount excreted through feces over five days. The resulting figure is divided by the total amount consumed to give a percentage. Results are strictly labeled as the “apparent digestibility” because the protocol does not take absorbed nutrients into account.

Popular dog food brands average 81 percent protein digestibility. Canine nutritionists accept that the minimum target is 80 percent, with ideal values ranging between 80 and 90 percent. Feeding diets exceptionally high in digestibility is equally as problematic. A dog’s large intestine is adapted to expect some undigested foods such as plant fibers and cartilaginous materials. Depriving the colon of these foods influences colonic health and reduces fecal bulk.

Sources of Proteins for Dogs

Dogs today have a huge array of choices when it comes to the food they eat. Your supermarket’s pet aisle will stock a range of flavors and styles, from fish and potato to turkey with jelly. Fortunately, choosing the best food for your dog doesn’t have to be difficult. Awareness of protein digestibility in dogs will aid your choice.

When choosing your dog’s new diet, it’s important to verify that the food contains real meat. Any meat meals and byproducts should be properly identified. Put more plainly: a label that lists “beef meal” or “fish byproducts” is fine; vague ingredients like “animal byproducts” or “meat meal” are not. Not only could these foods contain unsavory or dangerous sources of protein, but you could give your dog a protein they’re allergic to.


Beef contains up to 26.1 grams of protein per 100 grams of meat. This meat is also high in glutathione, a powerful tripeptide antioxidant made up of amino acids (cysteine, glutamic acid, and glycine). Grass-fed beef contains more glutathione than grain-fed. The antioxidant is necessary to support immune function, transport mercury away from the brain and making DNA.

beef for dogs
Glutathione is necessary to support immune function.

Beef is great for helping dogs to gain weight. It’s full of saturated and monounsaturated fats, including fatty acids such as oleic acid and palmitic acid. The fat content along with protein means that beef helps to build ore body weight. If your dog is recovering from illness or needs to put on weight, consider switching your dog to a beef-based diet.


The value of fish proteins is high. It has a stable composition of amino acids but is slightly deficient in methionine and threonine with an excess of lysine. Bluefin tuna, for example, has a very high protein content compared to other fish, offering up to 29.91 grams of protein per 100 grams of dry-cooked fish. Canned light tuna, which is usually made from a blend of skipjack and yellowfin tuna, supplies 29.13 grams of protein per 100 grams.

If you’re considering changing your dog’s diet to fish-based food, there are several reputable options available. You’ll find diets with different types of fish, ranging from tuna to salmon, and even formulas that pair the fish with other ingredients like sweet potato. So, which one is best for your pet? When choosing your dog’s new diet, there are a few things to consider. Is the diet complete and well balanced? Does it contain antioxidants to support a healthy immune system? Does it use real, high-quality fish?


Lamb, like other types of meat, provides plenty of protein (about 25.6 grams) and dietary fat when used in dog food formulas. Plus, most dogs love foods with the taste of lamb. If you look at the label on some foods, you’ll notice an ingredient called lamb meal. Lamb meal is processed and condensed at a rendering facility for use in pet food. During the process, water is removed, leaving highly concentrated protein and other essential nutrients like fat and calcium.


Chicken is one of the most frequently eaten meats worldwide. It contains at least 26 grams of protein as well as being rich in magnesium, selenium, potassium, and iron. All cuts of chicken are excellent sources of protein but some are significantly leaner. Chicken thighs and wings are higher in fat, while a raw chicken breast is the leanest and has the most protein. Chicken breast also has 75 percent water content. This makes it too watery to use in kibble. Because of this, food manufacturers often use chicken meal rather than plain chicken breast. Chicken meal does not contain feet, heads, feathers or intestinal contents. By drying out and grinding up chicken, the end product is a bioavailable, concentrated source of protein.

For most dogs, chicken is easily digestible, but its widespread usage in pet food means that there is a higher intolerance to chicken than other meats. If your dog is prone to dietary intolerances, consider other options to include in your dog’s diet.

Grain Products

Meat is low in carbohydrates, so a complete dog diet needs to include a quality source of carbohydrates. Grains are a great source of vitamins, fiber, and carbohydrates. They help dry kibble to maintain its shape and crunchy texture. Traditionally, corn and wheat have been the most common grains in commercial dog food.

Even though grain allergies in dogs are rare, statistically less than 1%, some owners feel more comfortable giving their pet grain-free food. If a grain-free diet is appropriate for your dog, be sure to choose grain-free food that’s complete and balanced. Alternatives to grain include sweet potatoes, beans, and peas.

Protein Digestibility – FAQs

Protein digestibility in dogs doesn’t have to be a complicated topic. If you have any questions, refer to our FAQs for more information on the digestibility of proteins in dogs.

What is the Most Digestible Protein for Dogs?

Out of all whole foods, eggs have the highest Protein Digestibility-Corrected Amino Acid Score (PDCAAS). On a scale of 0 to 1, the whole egg exceeds the scale with a score of 1.21. The score is a measure of a protein’s digestibility and quality.

The humble egg also contains the full range of essential amino acids: arginine, isoleucine, leucine, lysine, methionine, threonine, tryptophan, histidine, phenylalanine and valine. Eggs alone can’t fulfill all of a dog’s nutritional requirements, but in the context of protein, eggs excel at providing the essentials.

Dogs should never be given raw or undercooked eggs. Raw eggs are unsafe because they are a source of Salmonella. Prolonged feeding of raw egg whites leads to biotin deficiency in dogs. Fortunately, eggs don’t lose nutrients when cooked, and cooking even makes them more digestible – as long as the egg is cooked or boiled plain without additives, an egg is a safe treat for your pet. As a general rule, a dog should not eat more than one egg per day.

most digestible protein for dogs
Eggs have the highest protein digestibility.

What Meat is Easiest for Dogs to Digest?

Lamb, chicken, and beef are the most digestible meats for dogs. Muscle meats like lamb, chicken, and beef are said to be around 92 percent digestible, whereas organ meats like kidney, heart, and liver are rated at around 90 percent. Fish, on the other hand, is about 75 percent digestible. High-quality dog food brands will list these sources of protein first and will clearly label the type of meat in the ingredients.

What are the Nutritional Requirements for a Dog?

Most evidence points to dogs being omnivores, not carnivores. This means that they require a full range of nutrients, including carbohydrates, fat, and protein.

Carbohydrates should make up anywhere from 30 to 70 percent of a dog’s diet. Not only do cereal grains maintain the structure of kibble, but they also provide an excellent source of energy for dogs. Protein should make up around 18 to 25 percent of your dog’s diet. Dietary protein is necessary for dogs because it provides essential amino acids.

In addition, protein aids in the production of glucose for energy. Dogs selectively choose foods that are highest in protein – whether this is a complex response to their nutritional requirements or simply a matter of taste isn’t clear yet. Fat makes up about 10 to 15 percent of a healthy dog’s diet, with 5.5 percent being the minimum. Essential fatty acids are necessary for the diet to keep a dog’s skin and coat healthy. Without essential fatty acids, dogs develop coarse, dry hair, and even skin lesions.

The daily recommended allowances for vitamins are as follows:

  • Vitamin A: 379μg
  • Vitamin B1: 0.56mg
  • Riboflavin: 1.3mg
  • Vitamin B6: 0.4mg
  • Niacin: 4mg
  • Vitamin K: 0.41mg
  • Pantothenic Acid: 4mg
  • Vitamin B12: 9μg
  • Vitamin D: 3.4μg
  • Folic acid: 68μg
  • Vitamin E: 8mg
  • Choline: 425mg

The daily recommended allowances for minerals are as follows:

  • Calcium: 1g
  • Phosphorus: 0.75g
  • Magnesium: 150mg
  • Sodium: 200mg
  • Potassium: 1g
  • Chlorine: 300mg
  • Iron: 7.5mg
  • Copper: 1.5mg
  • Zinc: 15mg
  • Manganese: 1.2mg
  • Selenium: 90μg
  • Iodine: 220μg
dogs choose food higher in protein
Dogs selectively choose high protein foods.

What is a Dog Nutritionist?

Canine nutritionists offer dietary advice and diet-based treatments for dogs. These specialists work in several roles, including consulting services, developing pet food supplements, working in veterinary schools, and government agencies. Additionally, some nutritionists are self-employed. A nutritionist might create weight control plans for dogs or create diet plans for dogs with allergies.

What to Feed Dogs with Gastrointestinal Problems?

Before you start searching for a home remedy for your dog, you should figure out what’s causing your dog to have gastrointestinal problems. Some dogs are sensitive to certain ingredients. Others will have more serious underlying health conditions. When the problem occurs for a prolonged amount of time, make an appointment with your veterinarian to determine the cause of your dog’s gastrointestinal problems.

Some dogs don’t digest specific proteins well. If you feed your dog a chicken-based diet, try changing to a different protein source like lamb or beef. Most commercial pet foods contain sufficient amounts of vitamins and minerals. However, raw diets and home-made diets sometimes fail to provide enough vitamins and minerals. Your dog could be struggling with a nutrient deficiency. Consult with your veterinarian or a nutritionist to ensure that you feed your dog all of the required nutrients for adequate digestion.

The AKC recommends preparing bland meals at home for dogs with upset stomachs who show signs of appetite loss. A simple meal of cooked chicken with rice might help to settle gastrointestinal upset. This only applies to short-term cases – if your dog is suffering gastrointestinal problems for an extended period of time, it’s pivotal that you seek veterinary advice.

Protein digestibility in dogs is an important element to consider when choosing your dog’s food. Certain proteins are more digestible than others. Some dogs also have sensitivities or allergies to specific food products.

2 comments on “Protein Digestibility in Dogs – Definition, Bioavailability, Amino Acids & Consequences”

  1. Lynn

    I’m just now starting to research bioavailability and am wondering something.

    If my dog eats turkey and chicken, which has a biological value of 79, what does that mean? Is that 79%? If I were to give my dog a serving of chicken that had 26 grams of protein by nutritional analysis, is he only going to get 79% of that 26?

    So if his daily requirements were 100 grams of protein, by nutritional analysis, he’s never going to actually get that 100 grams unless he actually gets more? Like 140 grams might give 100 grams that are bioavailable……. this is just an example, not exact figures. My dog has kidney disease. I aim for him to have a certain amount of protein each day. But if only a certain amount of protein is bioavailable…….. he’s not getting as much protein out of I thought he was…….

    Am I making sense at all? Lol. It makes sense in my mind but maybe I’m overthinking it. Plus he gets cooked meat, which I’ve read also changes bioavailability. So I’m starting to consider at least getting some raw into his diet.

  2. Lynn

    ***** there’s a typo in my original comment because I was doing talk-to-text.

    “…..he’s not getting as much protein as I thought he was…….”

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