The proteins (or protides) whose function is essentially plastic, are nitrogenous substances that are used in the sustenance of the organism, in the growth and production of hair, nails and teeth.
A lack of proteins leads to a series of quite serious problems on the maintenance of the organism, on growth, on the integrity of the immune defenses and on the production of enzymes and hormones.
Proteins can be of animal or vegetable type. Those animals are more valid for dogs as they are richer in essential amino acids as well as more digestible. These proteins are contained in meat, milk and derivatives, eggs and fish.
Vegetable proteins are present in large quantities in roasted soy flour. The lipids that have a double function, energetic and plastic, are fatty substances of animal or vegetable origin, which are transformed into triglycerides.
Lipids carry vitamins, promote resistance to effort and the body stores them as reserve substances.
We find lipids in vegetable oils and animal fats. The carbohydrates have a mainly energetic function and to a small extent also plastic. They are divided into sugars, cellulose (present in vegetables), starch (contained in cereals and legumes).
