Protein is best known for supplying amino acids to build hair, skin, nails, muscles, tendons, ligaments, and cartilage. It also plays a main role in hormone production.
The protein in dog foods can be supplied by animal sources, plant sources or a combination of the two. High-quality animal-source proteins contain all of the essential amino acids dogs need, while a single plant-based protein might not contain adequate amounts of some essential amino acids.
Common animal-based protein sources used in pet food include chicken, lamb, fish, and beef.
Even though they are often fed plant-based diets, dogs are not herbivores. While dogs are technically considered to be omnivores—animals that eat both animal- and plant-based foods—they should be treated primarily as carnivores to better fulfill their specific nutritional requirements.
Dogs are members of the Canidae family. This family also includes the wolf, coyote, fox, and jackal. The ancestors and relatives of today's common dog hunted animals and ate them as a means of survival.
The body structure of domestic dogs is similar to that of their ancestors and relatives and is ideal for eating prey. Dogs have the enlarged carnassial teeth after which carnivores are named. Their gastrointestinal tract is simple and does not have the capacity to digest large amounts of plant products.
Animal-based proteins help dogs achieve optimal health.
Dog-food products described as light, lite, or low calorie must meet specific calorie levels set by the Association of American Feed Control Officials (AAFCO), while dog foods named “less” or “reduced calorie” must show a percent reduction in calories as compared to a product in the same moisture-content category. The following table shows the guidelines as set by AAFCO for both dog and cat foods for determining whether a product can use the term “light.”
| Food Texture | Moisture Content | Dog Foods Maximum kcal ME/kg | Cat Foods Maximum kcalME/kg |
|---|---|---|---|
| Dry | less than 20% moisture | 3,100 | 3,250 |
| Semi-Moist | between 20 and 64% moisture | 2,500 | 2,650 |
| Canned | 65% or more moisture | 900 | 950 |
Like light versus reduced-calorie foods, lean or low-fat dog-food products must meet specific fat levels set by AAFCO, and less-fat or reduced-fat dog-food products need to show a percent reduction in fat as compared to a product in the same moisture category. AAFCO guidelines for dog and cat foods with “lean,” “low fat,” or similar words are shown in the following table.
| Food Texture | Moisture Content | Dog Foods Maximum % Crude Fat | Cat Foods Maximum % Crude Fat |
|---|---|---|---|
| Dry | less than 20% moisture | 9 | 10 |
| Semi-Moist | between 20 and 64% moisture | 7 | 8 |
| Canned | 65% or more moisture | 4 | 5 |