Cats and dogs require a lot of protein for activity such as cell regeneration, growth, gestation, lactation and physical effort.
Proteins are molecules made up of amino acids in a predefined chain that determine their nature and their roles. Amino acids, which are produced by breaking down dietary proteins in the digestive tract, then serve as a basis of the body’s synthesis of the proteins it needs to build or regenerate its organs and structures, convey certain molecules, send messages from one organ to another (hormones) and combat disease (antibodies), among other things.
Proteins are found in a concentrated form in animal products (meat, fish, eggs, dairy products) and some vegetable products (cereal gluten, lentils, peas, soy, yeast). Cereals added a dog or cat's diet helps to provide proteins.