FAQ: Nutrients

Pet Food Ingredients

Pet Food Ingredients

Pet food ingredients are selected to deliver the nutrients dogs and cats need for complete and balanced nutrition at each life stage. Every ingredient serves a specific nutritional purpose—such as providing essential amino acids, fats, vitamins, and minerals or supporting particular metabolic and lifestyle needs. 

Understanding what ingredients contribute, and why they are included in a formulation, can help veterinary professionals and pet owners assess product quality and better evaluate nutritional differences among commercial pet foods. 

TABLE OF CONTENTS 

Protein Ingredients 

What are the main sources of protein in pet food?

Protein in pet food can come from both animal and plant sources. 

Animal-derived proteins typically originate from the human food chain and may include muscle meat as well as nutrient-dense tissues that are less commonly consumed by people, although this may vary by country and culture. These ingredients may be listed as “animal by-products” or “animal derivatives,” depending on regional labeling requirements. When properly processed, these ingredients supply essential amino acids and can be highly digestible. 

Plant-based proteins are commonly obtained from ingredients such as corn, soybeans, peas, lentils, wheat, and potatoes. These may appear on labels with their source (e.g., corn, soybeans), the specific component used (e.g., soy flour), or the processing (e.g., soybean meal, hydrolyzed soy protein). Many plant proteins provide valuable amino acids and functional properties when included in balanced formulations. 

Both animal and plant protein sources can contribute effectively to meeting a pet’s total amino acid needs when selected and processed appropriately. Understanding these ingredients helps distinguish differences among diets and supports informed nutritional recommendations. 

What is a “high-quality” dietary protein? 

When defining a high-quality protein, both digestibility and bioavailability are important. 

A protein is defined as highly digestible when it is easily broken down into amino acids that can then be absorbed from the gut into the bloodstream and into the body’s tissues and cells. Less digestible proteins are not as easily broken down during digestion, so fewer amino acids are available for absorption by the body. Undigested protein is excreted in the feces. 

Proteins are defined as bioavailable when the amino acids they provide are available for use by body cells and tissues. 

Both animal and plant sources can provide high-quality protein when included in diets for pets. However, the processing and cooking (manufacturing) of these ingredients can also increase or decrease their digestibility and bioavailability,1 and is taken into account during the manufacturing process. 

For more information about how pet food is made, see Cooking Processes & Commercial Pet Foods. 

Are animal-sourced proteins better than plant-sourced proteins? 

In general, the source of the protein is not as important as the amino acids that it provides to the pet. Each protein ingredient will provide a unique set of amino acids. 

Most protein ingredients do not contain all the essential amino acids in the right proportions. Most plant-sourced proteins lack one or more of the essential amino acids. Only meat and fish proteins contain taurine, which is essential for cats. However, a combination of plant proteins, for example, soy and corn, can complement each other because the amino acids that are deficient in one are present in the other. Combining different protein ingredients in a pet food ensures the diet provides all the essential amino acids a pet needs, in the correct balance and quantity.1 

What are by-products? 

By-products are defined as all the non-muscle, edible parts of an animal. According to the Association of American Feed Control Officials (AAFCO), hide, horns, teeth, hoofs, claws, beaks, intestinal contents and feathers from poultry are not considered by-products.2 By-products used in pet food include organ meat such as liver, spleen, and kidney. 

By-products are integrated into pet food either whole or as dried meal and provide a quality, digestible source of protein, vitamins, minerals, and healthy fats. 

Are by-products lower quality than meat or poultry? 

By-products can provide highly digestible, good quality protein3 and other nutrients, contributing to a high-quality pet food. 

By-products often provide more essential nutrients than muscle meat.1 Kidney and liver, for example, can contain greater than 5 to 10 times more riboflavin (vitamin B2) than lean meat, while also providing a good source of other B vitamins, vitamins A and C, and several essential minerals. Many organ meats also contain more healthy fats (e.g., omega-3 fatty acids) when compared to muscle meat.4 

Protein from by-product meals can be as digestible as food made with fresh meats or poultry,3 but not all by-product meals are equal in quality.5,6 Some manufacturing processes can impact digestibility and protein quality, with higher temperatures causing damage and reduced digestibility.5,7,8 Therefore, it is important that manufacturers of quality pet foods use by-products and meals from suppliers with stringent quality control standards and understand how to properly cook products with by-products. 

Would a wild dog or cat eat by-products? 

Wolves and other wild and feral animals kill and eat prey. When they do, they do not select just the prime rib or the breast meat. Instead, they consume nearly the whole animal. When wolves kill their prey, the first things usually consumed are the abdominal organs or “by-products.”9 Afterwards, they eat what remains, leaving little behind. 

Why shouldn’t pet foods just be made with meat? 

In addition to by-products being highly nutritious, there is also an environmental benefit from using them in pet food.10 Muscle meat from livestock amounts to only 32% to 48% of their body weight; much of the remainder is considered by-products,4 which are environmentally costly to dispose of. Therefore, it is essential for sustainability reasons that by-products be used for their best and most appropriate uses, whether for consumption by people, pets and livestock or for industrial uses, and not wasted. 

What organs are used in pet food? 

There are often misunderstandings about the benefits of including organs, also known as offal, in pet food. Organs such as liver, spleen, and kidney are high-quality sources of nutrition for pets. In many cases, these ingredients have increased concentrations of essential nutrients compared to skeletal muscle (meat). Organs are not a cheaper source of nutrition and may be considered a delicacy for humans in many countries. In the European Union, pet food labels may refer to “meat and animal derivatives,” which covers a wide range of animal products including meat (skeletal muscle), organs (offal), and meat and animal meals.11 In addition to being beneficial from a nutritional perspective, using organs in pet food has environmental benefits. 

Why are organs included in dog and cat food? 

Including organs in a pet food can make the pet food highly nutritious, with nutrients that are easy to digest and absorb. Organs can provide the highly concentrated, high-quality amino acids and protein that pets need as well as other essential nutrients such as vitamins, minerals, and fatty acids. Organs can often provide a higher concentration of essential nutrients versus muscle meat and may provide different nutrients compared to meat,1 which helps create a complete and balanced diet to help pets thrive. For example, kidney and liver can contain greater than 5 to 10 times more riboflavin (vitamin B2) than lean meat.4,12 Organs can also provide healthy fats, taurine, B vitamins, vitamin A, and several essential minerals. Therefore, including organs in pet food helps provide a dog or cat with all the nutrients needed for them to thrive. 

In addition to being highly nutritious, protein from organs can be as digestible as food made solely with skeletal muscle.5,6 Highly digestible ingredients are easily broken down and the nutrients are well assimilated. However, like with any ingredient, improper manufacturing processes can impact digestibility and protein quality. It is important that manufacturers use organs from suppliers with stringent quality control standards. 

What is the environmental benefit of using organs in dog and cat food? 

In addition to being highly nutritious, there is also an environmental benefit to using organs in pet food.10 One environmental benefit is reduction of waste. More tissue from fewer animals is used to produce a high-quality, nutritious pet food when organs are included. Skeletal muscle from livestock accounts for only 32% to 48% of their body weight,4 so using skeletal muscle (meat) alone could be environmentally costly if the remainder is not utilized. Using nutritious parts of the animal in addition to skeletal muscle (i.e., organs), in a pet food can therefore help reduce waste while helping provide high-quality nutrition. 

What are alternative proteins? 

Alternative proteins, which are generally considered protein sources other than the traditional animal sources such as beef and chicken, are being increasingly utilized in both human and pet food. Alternative proteins include proteins from edible insects (e.g., crickets, beetles, and black soldier fly larvae) and invasive fish species (e.g., Asian Carp), as well as cultured proteins (also known as manufactured, cultivated, or cell-based proteins), and plant protein sources that have not historically been used in pet food (e.g., fava beans). 

Why use alternative proteins in pet food? 

Pet food manufacturers may use alternative proteins as an approach to sustainability. As ingredients in food for both humans and pets, animal proteins are becoming more limited in supply and carry a greater environmental footprint.13 As a result, alternative protein sources are being identified to minimize reliance on animal proteins to meet the nutritional needs of pets. 

The use of alternative proteins also helps conserve land, water, and energy resources and reduce greenhouse gas emissions, thus decreasing the environmental impact of pet food.13 

Some alternative proteins may be able to function as novel proteins in pet food. Novel protein diets may be helpful in cases of suspected food intolerances or food allergies to avoid feeding proteins the pet has previously been exposed to. However, feeding novel proteins will not prevent pets from developing a food allergy.14 

Can alternative proteins meet the nutritional needs of pets? 

Pets require nutrients, such as protein and essential amino acids, not specific ingredients. In general, the source of the protein is not as important as protein digestibility and the specific amino acids that a food provides to the pet. Each protein ingredient provides a unique set of amino acids. 

Individual protein ingredients may not contain all the essential amino acids in the right proportions to meet a pet’s needs. However, combining complementary protein ingredients, which may come from alternative, traditional plant-based, and/or animal sources, ensures a complete diet provides all the essential amino acids a pet needs, in the correct balance and quantity.1 

Pet food ingredients—whether from alternative, traditional plant-based or animal-based sources—are strictly regulated.15–17 In addition, all ingredients in Purina pet foods must also meet the company’s stringent safety and quality standards before they are included in the food. 

 

References

Grain Ingredients 

Why is there grain in my pet’s food? 

Grains are a rich source of valuable nutrients for pets. Grains are the seeds of cereal grasses such as rice, oats, barley, and corn that help meet the body’s crucial need for glucose, an essential source of energy. Whole grains typically contain about 65% to 75% complex carbohydrates and less than 2% sugar. 

They also provide protein, fiber, essential fatty acids, B vitamins and minerals.1 

Wild dogs and cats don’t eat grains, so why should my pet? 

Today’s dogs and cats can readily digest and use properly cooked grains. As modern dogs evolved from wild canids, genetic studies show that domestic canines acquired more genes that code for enzymes that can help digest grains.2 

Although domestic cats are carnivores—like their wild ancestors—and need certain nutrients found naturally in animal tissue, this does not mean that they can only eat meat or should not eat grains. 

Even though cats use different metabolic pathways than other species use for digesting carbohydrates, research shows that cats can digest and use grains—with an efficiency greater than 90%.3–5 

What are the most common triggers of allergic reactions in pets? 

Food allergies in pets are less common than environmental or flea allergies, and among food allergies, grains are not typically the source. However, all of these allergies may lead to similar skin and gastrointestinal symptoms, making a diagnosis difficult.6,7 

If an adverse food reaction does occur, studies show it is typically caused by an individual’s immune system reacting to the size or structure of a specific protein and to sensitization from previous exposure—not to the carbohydrates in grains. 

Grains are not among the most reported food allergens in either dogs or cats. In dogs, the top three food allergens are proteins from beef, dairy or chicken. In cats, the most commonly reported food allergens are from beef, chicken or fish.8 

Can my pet be allergic to gluten? 

Glutens are the protein component of grains that may trigger allergies, but not all glutens are alike. The gluten from wheat, barley and rye contains “gliadins” that may trigger adverse food reactions in people with celiac disease.9 

While specific lines of Irish Setters have a heritable form of gluten-sensitive enteropathy that is similar to celiac disease in people, this is not a common health condition in dogs or cats.10,11 Gliadin is not found in gluten from corn or rice, so these are unlikely to trigger an allergic response. 

 

References

Biotics: Pre-, Pro-, and Postbiotics

What is the difference between a prebiotic and a probiotic? 

Although the names are similar and are often confused, prebiotics and probiotics are very different. However, they do have a (symbiotic) relationship, one being the “food” for the other. 

Probiotics are live, beneficial microorganisms (or bacteria) that when consumed in adequate amounts, can provide health benefits to the pet.1 Hundreds of bacterial species can be found in the gut, some are “good” (e.g., lactobacillus and bifidobacteria) and some potentially pathogenic (disease causing, e.g., clostridia). Collectively the bacteria that colonize the intestinal tract are known as the microbiota.2 The objective is to have an optimal balance between the good and the bad bacteria to help minimize the risk of digestive upsets. 

A prebiotic is a dietary fiber that when added to the pet’s diet, helps nourish and feed the good bacteria. Examples of prebiotics found in pet foods include chicory, a source of inulin, and wheat aleurone. 

What are the benefits of providing prebiotics in the diet? 

  • Prebiotics are often referred to as the “fuel” for the good bacteria. Prebiotics are broken down or “fermented” by beneficial bacteria in the intestine, predominantly in the colon, or large intestine.3 This fermentation results in the production of short-chain fatty acids, which have positive effects on gut health.
    • Intestinal cells use short-chain fatty acids, especially butyrate, as an energy source.1,3 This enables the intestinal cells to grow and multiply, expanding the surface area of the colon’s inner lining, which helps maximize nutrient absorption across the intestinal wall.1,3
    • When fermented by beneficial bacteria, wheat aleurone and inulin are excellent sources of butyrate.
  • Since “good bacteria” can preferentially use prebiotics as an energy source, prebiotics in the diet can also help stimulate the growth of beneficial bacteria while inhibiting growth of pathogenic bacteria.3
    • Multiple Purina studies have shown that when dogs and cats were fed the prebiotic chicory, levels of good bacteria (e.g., bifidobacteria and lactobacillus) increased and levels of pathogenic bacteria (e.g., clostridia) decreased.4–8
  • Butyrate also helps lower the intestinal pH, creating an optimal environment for beneficial bacteria to thrive.2
  • Prebiotics can help reduce imbalances in the microbiota that may occur with infection, stress, increasing age, or a change in diet.1,2,4 

Can prebiotics affect fecal odor? 

Research by Purina and others has shown that prebiotics such as chicory can help reduce fecal odor in dogs and cats.6,9,10 Certain bacteria (e.g., clostridia) found in the colon ferment undigested protein resulting in by-products such as ammonia and indoles which contribute to fecal odor. Adding prebiotics to the diet helps reduce the levels of clostridia and ultimately leads to a decrease in the level of malodorous by-products.9,10 

Prebiotics have also been shown to reduce urine odor in cats by decreasing the level of ammonia in the urine.10 

What is a probiotic? 

A probiotic is defined by the International Scientific Association for Probiotics and Prebiotics (ISAPP) as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.”11,12 Probiotics have the potential to provide many benefits outside the gastrointestinal tract in systems affected by the gut microbiome, such as the brain. 

Why would my pet need probiotics? 

The intestinal tract—or gut—is home to trillions of bacteria that can have a huge impact on overall pet health.13 An imbalance in bacterial populations can affect the body’s immune system, lead to digestive disorders, inflammation of the intestines or diarrhea.14,15 The gut microbiota can even affect brain development and behavior.16 Probiotics are live bacteria that can help to shift gut microbiota toward more beneficial bacterial species, helping maintain an optimal balance. 

Common causes of imbalanced gut bacteria: 

  • Antibiotics
  • Stress
  • Age
  • Illness
  • Diet change 

How do probiotics work? 

The most important immune-related function of the “good” bacteria is to protect from infection by harmful bacteria.17 The beneficial bacteria in probiotics prevent potentially pathogenic bacteria from flourishing by competing for space, secreting antibacterial substances, nourishing gut cells, and creating a more acidic environment that is unfavorable for pathogens.14 

Maintaining an optimal balance of “good” and “bad” bacteria also improves fecal quality and can reduce flatulence.17 Beyond the gut, probiotics can also have positive impacts on behavior, helping anxious dogs maintain calm behavior.18  

A Purina study on the effects of a strain of Bifidobacterium longum on anxiety in dogs resulted in significantly less anxious behaviors such as barking, jumping, spinning and pacing. Additionally, 83% of dogs studied had lower levels of cortisol, and 75% had lower heart rates.18 

How are probiotics given to pets? 

Probiotics can be provided in pet food or as a dietary supplement. Regardless of how the probiotic is administered, the probiotic strain (or strains) should be chosen based on the desired effect and the evidence of the probiotic’s efficacy in the target species. 

How do I know if a probiotic is good? 

Probiotics are extremely strain-specific, and different strains within the same species can have very different health effects. Probiotics are also dose-dependent; therefore, clinical research is needed to establish the correct required amount of a particular strain of bacteria. 

To be effective, studies should demonstrate that a particular probiotic: 

  • Remains live and viable until the time of consumption
  • Is resistant to digestion by stomach acids and intestinal enzymes
  • Reduces or prevents the adherence of pathogenic bacteria in the gut
  • Produces products that are unfavorable to the growth of “bad” bacteria
  • Promotes normal and balanced bacterial populations in the gut
  • Is safe for the pet
  • Enhances the overall health of the pet19 

Is it better to have more bacteria, or more strains of bacteria? 

Probiotic effectiveness is very strain-specific and dose-dependent. Different strains within the same species of bacteria can provide very different health effects, so blending them may not always be complementary and careful research needs to be done to ensure they do not work against each other.20,21 It is also important to consider that more CFU (colony-forming units) on the label of a product may not mean it is more effective, unless there is research showing the benefits of using a higher dosage. It is key that a product deliver the right dosage of a single, or blend of, probiotic proven by research to be effective for specific health concerns (i.e., diarrhea, general GI upset, anxiety, etc.).22 

What are postbiotics? 

Postbiotics are preparations of inanimate (non-living) microorganisms and/or their components (such as parts of the cell wall, enzymes, proteins, vitamins, short-chain fatty acids, and polysaccharides) that confer a health benefit.23,24 They can be produced by beneficial commensal microorganisms in the gut or provided through dietary supplementation with probiotics or postbiotics. 

Postbiotic is the currently accepted term, according to the International Scientific Association for Probiotics and Prebiotics (ISAPP); terms that have been used in the past to describe postbiotics include paraprobiotics, ghost probiotics, inactivated probiotics, non-viable probiotics, metabiotics, and Tyndallized probiotics.23,25 

What are some examples of postbiotic components? 

Examples of postbiotic components include: 

  • Short-chain fatty acids
  • Polysaccharides
  • Bacteriocins
  • B vitamins
  • Urolithin A and B
  • Phospholipids
  • Vitamin K
  • Phytoestrogens
  • Teichoic and lipoteichoic acids
  • Peptidoglycans
  • Pili-type structures
  • Cell fractions/cell walls 

How do postbiotics differ from probiotics or prebiotics? 

Probiotics are living microorganisms, whereas postbiotics do not contain live cells. Some, but not all, postbiotics are derived from probiotics;26 however, a postbiotic is not simply a dead probiotic and the efficacy of an inanimate microorganism cannot be predicted by the efficacy of its live form.27 Some of the benefits of probiotics may actually be due to the metabolites they produce; therefore, postbiotics may provide these same benefits without the need for living microorganisms.26,28–30 

Prebiotics are dietary fibers that help nourish and feed the beneficial bacteria in the gut. Postbiotics do not serve as food sources for the bacteria; instead, they exert their actions through cell-produced molecules, metabolites, and activation of receptors on intestinal and immune cells. 

How do postbiotics work? 

The exact mechanisms by which postbiotics work are not fully understood, and are expected to vary with the postbiotic. To date, research suggests postbiotics may have the following beneficial functions:23–25,27,29–35 

  • Antimicrobial activity to suppress harmful microorganisms (pathogens)
  • Antioxidant activity to reduce free radical damage and oxidative stress
  • Anti-inflammatory activity via reduced production of inflammatory mediators
  • Provide a supportive environment for beneficial bacteria
  • Improve the health of the gut barrier by enhancing tight junctions and promoting growth of intestinal epithelial cells
  • Immunomodulation through interactions with the gut-associated lymphoid tissue (GALT)
  • Metabolic support through microbiome modulation and increased energy expenditure 

What benefits might postbiotics offer pets? 

Because postbiotics do not contain living microorganisms, they are very stable and have a long shelf-life.23,24 Similar to probiotics, postbiotics vary in their activity and their selection should be based on proven efficacy and safety in the same species and for the condition being addressed. 

Postbiotics’ specific benefits for pets are the subject of ongoing investigation, but benefits observed in humans and other animals include: 

  • Anti-diarrheal properties23,25,27,30,33,36
  • Improved nutrient absorption23,25,36–38
  • Improved gut barrier function29,30
  • Improved immune function27,30,37
  • Improved weight gain and/or production in production animals36,38–40
  • Reduced physiologic stress29
  • Facilitated weight management30
  • Improved muscle strength, exercise performance, and mitochondrial health41 

Postbiotics may also be promising alternatives to antibiotics because they have been shown to reduce GI pathogens.29,33,39,40 

 

References

Medium-Chain Triglycerides (MCTs) 

How do medium-chain triglycerides differ from long-chain triglycerides (LCTs)? 

MCT fatty acids are 6–12 carbons long, and LCT fatty acids >16 carbons. With shorter fatty acid chains, MCTs: 

  • Are more easily digested, and their fatty acids more rapidly absorbed with most transported directly to the liver via the portal vein1
  • Yield more ketone bodies when oxidized1 

MCTs are found in coconut and palm kernel oils, LCTs in animal fats and vegetable oils. 

How can an MCT-supplemented diet help dogs? 

  • Brain health. Healthy brains rely primarily on glucose for energy. With age, brain glucose metabolism often becomes inefficient, creating an energy deficiency, with brain regions critical to cognition most affected. Metabolic alongside functional and structural changes may result in age-associated cognitive decline, which may progress to cognitive dysfunction syndrome.2,3 

    Similarly, in dogs with idiopathic epilepsy, brain glucose metabolism is disrupted, predisposing to more seizures.4 Cognitive impairment, such as memory loss,5,6 attention deficit hyperactivity disorder-like behaviors,7 and/or anxious behaviors,7 may also develop. 

    Dietary MCT-derived medium-chain fatty acids (MCFAs) and ketone bodies can provide an alternative source of energy. In addition, the MCFA decanoic acid may inhibit seizures by blocking AMPA excitatory receptors on neurons.8 

    Purina-supported research demonstrated: 

  • Cognitive ability improved in senior dogs fed an MCT-supplemented diet. In contrast to control dogs, MCT diet-fed dogs performed better as the cognitive tests became more demanding. Positive learning changes occurred within the first month.3
  • When dogs with refractory idiopathic epilepsy (receiving ≥ 1 anticonvulsant medication[s]) were fed an MCT-supplemented diet, seizure frequency significantly decreased. Seventy-one percent of dogs improved, with 48% achieving ≥ 50% reduction in frequency and 14% becoming seizure-free. Improvement was seen as early as day 1.9 Serum concentrations of anticonvulsant medication(s) were not significantly affected.9 Adverse behaviors (e.g., chasing and fear towards strangers) declined when dogs were fed the MCT diet.7

  • Cardiac health. For energy, a healthy heart relies mostly on mitochondrial oxidation of LCFAs.10 

    Research shows dogs with early stage myxomatous mitral valve disease (MMVD) have less efficient cardiac energy production.11 MCT-derived MCFAs and ketone bodies can act as an alternative energy source.12

    Purina research demonstrated: 

    • Dogs with asymptomatic MMVD fed a special diet including MCTs were less likely than control dogs to progress from stage B1 to B2. Cardiac left atrial diameter, on average, decreased 3% in dogs fed the special diet, but increased 10% in control dogs.13
    • MMVD dogs fed the special diet showed improved energy metabolism and decreased markers of oxidative stress and inflammation.14
  • Gastrointestinal health. With LCFA maldigestion or malabsorption (e.g., in dogs with chronic enteropathy, exocrine pancreatic insufficiency, liver disease, or lymphangiectasia), a low-fat diet that restricts LCTs is usually fed.15–17 Since fats provide a concentrated form of energy, low-fat diets can be lower in calories, resulting in increased food intake required to meet energy needs. MCTs can serve as another fat source to provide an easily digestible energy source.15,17 

Can MCTs benefit cats? 

Research evaluating optimal dietary inclusion levels and benefits is ongoing. A Purina-funded study showed a diet containing 5.5% MCTs from coconut oil to be palatable and acceptable to cats.18 

 

References

Neutralizing Allergens

Protein Ingredients 

  1. Laflamme, D. P., Izquierdo, O., Eirmann, L., & Binder, S. (2014). Myths and misperceptions about ingredients used in commercial pet foods. Veterinary Clinics of North America: Small Animal Practice, 44, 689–698. doi: 10.1016/j.cvsm.2014.03.002
  2. Association of American Feed Control Officials. (2023). 2023 Official Publication. Association of American Feed Control Officials, Inc.
  3. Murray, S. M., Patil, A. R., Fahey, G. C., Merchen, N. R., & Hughes, D. M. (1997). Raw and rendered animal by-products as ingredients in dog diets. Journal of Animal Science, 75, 2497–2505.
  4. Jayathilakan, K., Sultana, K., Radhakrishna, K., & Bawa, A. S. (2012). Utilization of byproducts and waste materials from meat, poultry and fish processing industries: A review. Journal of Food Science and Technology, 49, 278–293. doi: 10.1007/s13197-011-0290-7
  5. Johnson, M. L., Parsons, C. M., Fahey, G. C., Merchen, N. R., & Aldrich, C. G. (1998). Effects of species of raw material source, ash content, and processing temperature on amino acid digestibility of animal by-product meals by cecectomized roosters and ileally cannulated dogs. Journal of Animal Science, 76, 1112–1122.
  6. Dozier, W. A., Dale, N. M., & Dove, C. R. (2003). Nutrient composition of feed-grade and pet-food-grade poultry by-product meal. Journal of Applied Poultry Research, 12, 526–530. doi: 10.1093/japr/12.4.526
  7. Shirley, R. B., & Parsons, C. M. (2000). Effect of pressure processing on amino acid digestibility of meat and bone meal for poultry. Journal of Poultry Science, 79, 1775–1781.
  8. de-Oliveira, L. D., de Carvalho Picinato, M. A., Kawauchi, I. M., Sakomura, N. K., & Carciofi, A. C. (2011). Digestibility for dogs and cats of meat and bone meal processed at two different temperature and pressure levels. Journal of Animal Physiology and Animal Nutrition, 96, 1136–1146. doi: 10.1111/j.1439-0396.2011.01232.x
  9. Stahler, D. R., Smith, D. W., & Guernsey, D. S. (2006). Foraging and feeding ecology of the Gray Wolf (Canis lupus): Lessons from Yellowstone National Park, Wyoming, USA. The Journal of Nutrition, 136, 1923S–1926S. doi: 10.1093/jn/136.7.1923S
  10. Meeker, D. L., & Meisinger, J. L. (2015). Rendered ingredients significantly influence sustainability, quality and safety of pet food. Journal of Animal Science, 93, 835–847. doi: 10.2527/jas.2014-8524
  11. The European Pet Food Industry. (2019). FEDIAF code of good labelling practice for pet food. Retrieved August 21, 2023, from https://europeanpetfood.org/wp-content/uploads/2022/02/FEDIAF_labeling_code_2019_onlineOctober2019.pdf
  12. US Department of Agriculture, Agricultural Research Service. (2019). FoodData Central. Retrieved August 24, 2023, from https://fdc.nal.usda.gov
  13. Dobermann, D., Swift, J. A., & Field, L. M. (2017). Opportunities and hurdles of edible insects for food and feed. Nutrition Bulletin, 42, 293–308.
  14. Mueller, R. S., Olivry, T., & Prélaud, P. (2016). Critically appraised topic on adverse food reactions of companion animals (2): Common food allergen sources in dogs and cats. BMC Veterinary Research, 12, 9. doi: 10.1186/s12917-016-0633-8
  15. FEDIAF (The European Pet Food Industry). (2018, February). Guide to good practice for the safe manufacture of pet foods. https://europeanpetfood.org/wp-content/uploads/2022/03/FEDIAF_Safety_Guide_February_2018_online.pdf
  16. AAFCO, Inc. (2026). Ingredient standards. https://www.aafco.org/consumers/understanding-pet-food/ingredient-standards/
  17. FDA (2021, February 19). Pet food. https://www.fda.gov/animal-veterinary/animal-foods-feeds/pet-food 

Grain Ingredients 

  1. Lafiandra, D., Riccardi, G., & Shewry, P. R. (2014). Improving cereal grain carbohydrates for diet and health. Journal of Cereal Science, 59(3), 312–326.
  2. Axelsson, E., Ratnakumar, A., Arendt, M. L., Maqbool, K., Webster, M. T., Perloski, M., … & Lindblad-Toh, K. (2013). The genomic signature of dog domestication reveals adaptation to a starch-rich diet. Nature, 495(7441), 360–364. doi: 10.1038/nature11837
  3. de-Oliveira, L. D., Carciofi, A. C., Oliveira, M. C., Vasconcellos, R. S., Bazolli, R. S., Pereira, G. T., & Prada, F. (2008). Effects of six carbohydrate sources on diet digestibility and postprandial glucose and insulin responses in cats. Journal of Animal Science, 86(9), 2237–2246. doi: 10.2527/jas.2007-0354
  4. Kienzle, E. (2009). Carbohydrate metabolism of the cat 2. Digestion of starch. Journal of Animal Physiology and Animal Nutrition, 69, 102–114. doi: 10.1111/j.1439-0396.1993.tb00794.x
  5. Tanaka, A., Inoue, A., Takeguchi, A., Washizu, T., Bonkobara, M., & Arai, T. (2005). Comparison of expression of glucokinase gene and activities of enzymes related to glucose metabolism in livers between dog and cat. Veterinary Research Communications, 29(6), 477–485.
  6. Gaschen, F. P., & Merchant, S. R. (2011). Adverse food reactions in dogs and cats. Veterinary Clinics of North America: Small Animal Practice, 41(2), 361–379. doi: 10.1016/j.cvsm.2011.02.005
  7. Olivry, T., & Mueller, R. S. (2016). Critically appraised topic on adverse food reactions of companion animals (3): Prevalence of cutaneous adverse food reactions in dogs and cats. BMC Veterinary Research, 13, 51. doi: 10.1186/s12917-017-0973-z
  8. Mueller, R. S., Olivry, T., & Prélaud, P. (2016). Critically appraised topic on adverse food reactions of companion animals (2): Common food allergen sources in dogs and cats. BMC Veterinary Research, 12, 9. doi: 10.1186/s12917-016-0633-8
  9. Morón, B., Cebolla, A., Manyani, H., Alvarez-Maqueda, M., Megías, M., Thomas, M. del C., Lôpez, M. C., & Sousa, C. (2008). Sensitive detection of cereal fractions that are toxic to celiac disease patients by using monoclonal antibodies to a main immunogenic wheat peptide. American Journal of Clinical Nutrition, 87(2), 405–414.
  10. Garden, O. A., Pidduck, H., Lakhani, K. H., Walker, D., Wood, J. L., & Batt, R. M. (2000). Inheritance of gluten-sensitive enteropathy in Irish Setters. American Journal of Veterinary Research, 61(4), 462–468.
  11. Hall, E. J., & Batt, R. M. (1992). Dietary modulation of gluten sensitivity in a naturally occurring enteropathy of Irish setter dogs. Gut, 33(2), 198–205. 

Biotics: Pre-, Pro-, and Postbiotics 

  1. Case, L. P., Daristotle, L., Hayek, M. G., & Raasch, M. F. (2011). Canine and feline nutrition: A resource for companion animal professionals (3rd ed.). Mosby.
  2. Pinna, C., & Biagi, G. (2014). The utilization of prebiotics and synbiotics in dogs. Italian Journal of Animal Science, 13, 3107. doi: 10.4081/ijas.2014.3107
  3. Cave, N. (2012). Nutritional management of gastrointestinal diseases. In A. J. Fascetti & S. J. Delaney (Eds.), Applied veterinary clinical nutrition (pp. 175–219). Wiley-Blackwell. doi: 10.1002/9781118785669.ch12
  4. Grieshop, C. M., Flickinger, C., Bruce, K., Patil, A. R., Czarnecki-Maulden, G. L., & Fahey, G. C., Jr. (2004). Gastrointestinal and immunological responses of senior dogs to chicory and mannan-oligosaccharides. Archives of Animal Nutrition, 58(6), 483–494. doi: 10.1080/00039420400019977
  5. Cupp, C. J., Jean-Philippe, C., Kerr, W. W., Patil, A. R., & Perez-Camargo, G. (2007). Effect of nutritional interventions on longevity of senior cats. International Journal of Applied Research in Veterinary Medicine, 5(3), 133–149.
  6. Patil, A. R., Carrion, P. A., & Holmes, A. K. (2001). Effect of chicory supplementation on fecal microflora of cats. Federation of American Societies for Experimental Biology Journal, 15(4), A288.
  7. Czarnecki-Maulden, G. L., & Russell, T. J. (2000). Effect of chicory on fecal microflora in dogs fed soy-containing or soy-free diets. Federation of American Societies for Experimental Biology Journal, 14(4), A488.
  8. Czarnecki-Maulden, G. L., & Russell, T. J. (2000). Effect of diet type on fecal microflora in dogs. Federation of American Societies for Experimental Biology Journal, 14(4), A488.
  9. Terada, A., Hara, H., Oishi, T., Matsui, S., Mitsuoka, T., Nakajyo, S., Fujimori, I., & Hara, K. (1992). Effect of dietary lactosucrose on faecal flora and faecal metabolites of dogs. Microbial Ecology in Health and Disease, 5(2), 87–92. doi: 10.3109/08910609209141294
  10. Terada, A., Hara, H., Kato, S., Kimura, T., Fujimori, I., Hara, K., Maruyama, T., & Mitsuoka, T. (1993). Effect of lactosucrose (4G-β-D-galactosylsucrose) on fecal flora and fecal putrefactive products of cats. Journal of Veterinary Medical Science, 55(2), 291–295. doi: 10.1292/JVMS.55.291
  11. Hill, C., Guarner, F., Reid, G., Gibson, G. R., Merenstein, D. J., Pot, B., Morelli, L., Canani, R. B., Flint, H. J., Salminen, S., Calder, P. C., & Sanders, M. E. (2014). Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology, 11(8), 506–514. doi: 10.1038/nrgastro.2014.66
  12. International Scientific Association for Probiotics and Prebiotics. (2019). Probiotics. Retrieved July 31 from https://isappscience.org/wp-content/uploads/2019/04/Probiotics_0119.pdf
  13. Sender, R., Fuchs, S., & Milo, R. (2016). Revised estimates for number of human and bacteria cells in the body. PLoS Biology, 14(8), e1002533. doi: 10.1371/journal.pbio.1002533
  14. Kelly, M. (2006). The role of probiotics in GI tract health. Nestlé Purina PetCare, Purina Veterinary Diets.
  15. Ng, S. C., Hart, A. L., Kamm, M. A., Stagg, A. J., & Knight, S. C. (2009). Mechanisms of action of probiotics: Recent advances. Inflammatory Bowel Diseases, 15, 300–310. doi: 10.1002/ibd.20602
  16. Wiley, N. C., Dinan, T. G., Ross, R. P., Stanton, C., Clarke, G., & Cryan, J. F. (2017). The microbiota-gut-brain axis as a key regulator of neural function and the stress response: Implications for human and animal health. Journal of Animal Science, 95, 3225–3246.
  17. Czarnecki-Maulden, G. L., Kelly, M. R., & Cline, J. L. (n.d.). The –otics: pre and probiotics… What are they? Are they useful in your practice? Nestlé Purina PetCare.
  18. McGowen, R. T. S. (2016, March 31–April 2). Oiling the brain or cultivating the gut: Impact of diet on anxious behavior in dogs. Pet Nutrition: Beyond Essential, Nestlé Purina Companion Animal Nutrition Summit, Fort Lauderdale, FL, USA.
  19. Rolfe, R. D. (2000). The role of probiotic cultures in the control of gastrointestinal health. Proceedings of the Probiotic Bacteria: Implications of Human Health Symposium. Journal of Nutrition, 130, 396S–402S. doi: 10.1093/jn/130.2.396S
  20. Kekkonen, R. A., Kajasto, E., Miettinen, M., Veckman, V., Korpela, R., & Julkunen, I. (2008). Probiotic Leuconostoc mesenteroides ssp. cremoris and Streptococcus thermophilus induce IL12 and IFN-γ production. World Journal of Gastroenterology, 14, 1192–1203.
  21. Viljanen, M., Kuitunen, M., Haahtela, T., Juntunen-Backman, K., Korpela, R., & Savilhati, E. (2005). Probiotic effects on faecal inflammatory markers and on faecal IgA in food allergic atopic eczema/dermatitis syndrome infants. Pediatric Allergy and Immunology, 16, 65–71.
  22. Sanders, M. E. (2008). Probiotics: Definition, sources, selection, and uses. Clinical Infectious Diseases, 46, S58–S61. doi: 10.1086/523341
  23. Salminen, S., Collado, M. C., Endo, A., Hill, C., Lebeer, S., Quigley, E. M. M., Sanders, M. E., Shamire, R., Swann, J. R., Szajewska, H., & Vinderola, G. (2021). The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nature Reviews Gastroenterology & Hepatology, 18(9), 649–667. doi: 10.1038/s41575-021-00440-6
  24. Kaur, S., Thukral, S. K., Kaur, P., & Samota, M. K. (2021). Perturbations associated with hungry gut microbiome and postbiotic perspectives to strengthen the microbiome health. Future Foods, 4, Article 100043. doi: 10.1016/j.fufo.2021.100043
  25. Aguilar-Toalá, J. E., Garcia-Varela, R., Garcia, H. S., Mata-Haro, V., González-Córdova, A. F., Vallego-Cordoba, B., & Hernández-Mendoza, A. (2018). Postbiotics: An evolving term within the functional foods field. Trends in Food Science & Technology, 75, 105–114.
  26. Kataria, J., Li, N., Wynn, J. L., & Neu, J. (2009). Probiotic microbes: do they need to be alive to be beneficial? Nutrition Reviews, 67(9), 546–550. doi: 10.1111/j.1753-4887.2009.00226.x
  27. Spears, J. K., Czarnecki-Maulden, G., Ameho, C., & Reynolds, A. (2016, March 31–April 2). Beyond probiotics: Heat-treated probiotics in companion animal health. Pet Nutrition: Beyond Essential, Nestlé Purina Companion Animal Nutrition Summit, Fort Lauderdale, FL, USA.
  28. Cicenia, A., Santangelo, F., Gambardella, L., Pallotta, L., Iebba, V., Scirocco, A., Marignani, M., Tellan, G., Carabotti, M., Corazziari, E. S., Schippa, S., & Severi, C. (2016). Protective role of postbiotic mediators secreted by Lactobacillus rhamnosus GG versus lipopolysaccharide-induced damage in human colonic smooth muscle cells. Journal of Clinical Gastroenterology, 50(Suppl 2), S140–S144. doi: 10.1097/MCG.0000000000000681
  29. Humam, A. M., Loh, T. C., Foo, H. L., Izuddin, W. I., Zulkifli, I., Samsudin, A. A., & Mustapha, N. M. (2021). Supplementation of postbiotic RI11 improves antioxidant enzyme activity, upregulated gut barrier genes, and reduced cytokine, acute phase protein, and heat shock protein 70 gene expression levels in heat-stressed broilers. Poultry Science, 100(3), 100908. doi: 10.1016/j.psj.2020.12.011
  30. Mosca, A., Abreu, Y. A. A. T., Gwee, K. A., Ianiro, G., Tack, J., Nguyen, T. V. H., & Hill, C. (2022). The clinical evidence for postbiotics as microbial therapeutics. Gut Microbes, 14(1), 2117508. doi: 10.1080/19490976.2022.2117508
  31. Cicenia, A., Scirocco, A., Carabotti, M., Pallotta, L., Marignani, M., & Severi, C. (2014). Postbiotic activities of lactobacilli-derived factors. Journal of Clinical Gastroenterology, 48(Suppl 1), S18–S22. doi: 10.1097/MCG.0000000000000231
  32. Jensen, G. S., Benson, K. F., Carter, S. G., & Endres, J. R. (2010). GanedenBC30 cell wall and metabolites: anti-inflammatory and immune modulating effects in vitro. BMC Immunology, 11, 15. doi: 10.1186/1471-2172-11-15
  33. Lievin-Le Moal, V. (2016). A gastrointestinal anti-infectious biotherapeutic agent: the heat-treated Lactobacillus LB. Therapeutic Advances in Gastroenterology, 9(1), 57–75. doi: 10.1177/1756283X15602831
  34. Vallianou, N., Stratigou, T., Christodoulatos, G. S., Tsigalou, C., & Dalamaga, M. (2020). Probiotics, prebiotics, synbiotics, postbiotics, and obesity: Current evidence, controversies, and perspectives. Current Obesity Reports, 9(3), 179–192. doi: 10.1007/s13679-020-00379-w
  35. Wegh, C. A. M., Geerlings, S. Y., Knol, J., Roeselers, G., & Belzer, C. (2019). Postbiotics and their potential applications in early life nutrition and beyond. International Journal of Molecular Sciences, 20(19), 4673. doi: 10.3390/ijms20194673
  36. Loh, T. C., Thu, T. V., Foo, H. L., & Bejo, M. H. (2013). Effects of different levels of metabolite combination produced by Lactobacillus plantarum on growth performance, diarrhoea, gut environment and digestibility of postweaning piglets. Journal of Applied Animal Research, 41(2), 200–207. doi: 10.1080/09712119.2012.741046
  37. Izuddin, W. I., Loh, T. C., Foo, H. L., Samsudin, A. A., & Humam, A. M. (2019). Postbiotic L. plantarum RG14 improves ruminal epithelium growth, immune status and upregulates the intestinal barrier function in post-weaning lambs. Scientific Reports, 9(1), 9938. doi: 10.1038/s41598-019-46076-0
  38. Kareem, K. Y., Loh, T. C., Foo, H. L., Akit, H., & Samsudin, A. A. (2016). Effects of dietary postbiotic and inulin on growth performance, IGF1 and GHR mRNA expression, faecal microbiota and volatile fatty acids in broilers. BMC Veterinary Research, 12(1), 163. doi: 10.1186/s12917-016-0790-9
  39. Johnson, C. N., Kogut, M. H., Genovese, K., He, H., Kazemi, S., & Arsenault, R. J. (2019). Administration of a postbiotic causes immunomodulatory responses in broiler gut and reduces disease pathogenesis following challenge. Microorganisms, 7(8), 268. doi: 10.3390/microorganisms7080268
  40. Loh, T. C., Choe, D. W., Foo, H. L., Sazili, A. Q., & Bejo, M. H. (2014). Effects of feeding different postbiotic metabolite combinations produced by Lactobacillus plantarum strains on egg quality and production performance, faecal parameters and plasma cholesterol in laying hens. BMC Veterinary Research, 10, 149. doi: 10.1186/1746-6148-10-149
  41. Singh, A., D’Amico, D., Andreux, P. A., Fouassier, A. M., Blanco-Bose, W., Evans, M., Aebischer, P., Auwerx, J., & Rinsch, C. (2022). Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults. Cell Reports Medicine, 3(5), 100633. doi: 10.1016/j. xcrm.2022.100633 

Medium-Chain Triglycerides (MCTs) 

  1. Bach, A. C., & Babayan, V. K. (1982). Medium-chain triglycerides: An update. The American Journal of Clinical Nutrition, 36, 950–962.
  2. Myette-Côté, É., Soto-Mota, A., & Cunnane, S. C. (2022). Ketones: Potential to achieve brain energy rescue and sustain cognitive health during ageing. British Journal of Nutrition, 128(3), 407–423. doi: 10.1017/S0007114521003883
  3. Pan, Y., Larson, B., Araujo, J. A., Lau, W., de Rivera, C., Santana, R., Gore, A., & Milgram, N. W. (2010). Dietary supplementation with medium-chain TAG has long-lasting cognition-enhancing effects in aged dogs. British Journal of Nutrition, 103, 1746–1754.
  4. Han, F. Y., Conboy-Schmidt, L., Rybachuk, G., Volk, H. A., Zanghi, B., Pan, Y., & Borges, K. (2021). Dietary medium chain triglycerides for management of epilepsy: New data from human, dog, and rodent studies. Epilepsia, 62, 1790–1806.
  5. Packer, R. M. A., McGreevy, P. D., Salvin, H. E., Valenzuela, M. J., Chaplin, C. M., & Volk, H. A. (2018). Cognitive dysfunction in naturally occurring canine idiopathic epilepsy. PLoS ONE, 13(2), e0192182.
  6. Winter, J., Packer, R. M. A., & Volk, H.A. (2018).Preliminary assessment of cognitive impairments in canine idiopathic epilepsy. Veterinary Record, 182(22), 663.
  7. Packer, R. M., Law, T. H., Davies, E., Zanghi, B., Pan, Y., & Volk, H. A. (2016). Effects of a ketogenic diet on ADHD-like behavior in dogs with idiopathic epilepsy. Epilepsy & Behavior, 55, 62–68.
  8. Chang, P., Augustin, K., Boddum, K., Williams, S., Sun, M., Terschak, J. A., Hardege, J. D., Chen, P. E., Walker, M. C., & Williams, R. S. B. (2016). Seizure control by decanoic acid through direct AMPA receptor inhibition. Brain, 139, 431–433.
  9. Law, T. H., Davies, E. S., Pan, Y., Zanghi, B., Want, E., & Volk, H. A. (2015). A randomised trial of a medium-chain TAG diet as treatment for dogs with idiopathic epilepsy. The British Journal of Nutrition, 114(9), 1438–1447.
  10. van der Vusse, G. J., van Bilsen, M., & Glatz, J. F. C. (2000). Cardiac fatty acid uptake and transport in health and disease. Cardiovascular Research, 45, 279–293.
  11. Li, Q., Freeman, L. M., Rush, J. E., Huggins, G. S., Kennedy, A. D., Labuda, J. A., Laflamme, D. P., & Hannah, S. S. (2015). Veterinary medicine and multi-omics research for future nutrition targets: Metabolomics and transcriptomics of the common degenerative mitral valve disease in dogs. OMICS, 19(8), 461–470.
  12. Labarthe, F., Gélinas, R., & Des Rosiers, C. (2008). Medium chain fatty acids as metabolic therapy in cardiac disease. Cardiovascular Drugs and Therapy, 22, 97–106.
  13. Li, Q., Heaney, A., Langenfeld-McCoy, N., Boler, B. V., & Laflamme, D. P. (2019). Dietary intervention reduces left atrial enlargement in dogs with early preclinical myxomatous mitral valve disease: A blinded randomized controlled study in 36 dogs. BMC Veterinary Research, 15(1), 425.
  14. Li, Q., Laflamme, D. P., & Bauer, J. E. (2020). Serum untargeted metabolomic changes in response to diet intervention in dogs with preclinical myxomatous mitral valve disease. PLoS ONE, 15(6), e0234404.
  15. Tolbert, M. K., Murphy, M., Gaylord, L., & Witzel-Rollins, A. (2022). Dietary management of chronic enteropathy in dogs. Journal of Small Animal Practice, 63(6), 425–434. doi: 10.1111/jsap.13471
  16. Kathrani, A. (2021). Dietary and nutritional approaches to the management of chronic enteropathy in dogs and cats. Veterinary Clinics of North America: Small Animal Practice, 51(1), 123–136.
  17. Simpson, K. W., & Jergens, A. E. (2011). Pitfalls and progress in the diagnosis and management of canine inflammatory bowel disease. Veterinary Clinics of North America: Small Animal Practice, 41(2), 381–398.
  18. Trevizan, L., de Mello Kessler, A., Bigley, K. E., Anderson, W. H., Waldron, M. K., & Bauer, J. E. (2010). Effects of dietary medium-chain triglycerides on plasma lipids and lipoprotein distribution and food aversion in cats. American Journal of Veterinary Research, 71(4), 435–440.