Cats have higher requirements for proteins and amino acids (the individual components that make up a protein) than dogs. The cat appears to break down protein very rapidly and is unable to adapt when dietary supplies are low by reducing the rate of breakdown.
The cat is also very sensitive to arginine deficiency. This amino acid is essential for metabolism and the cat not only breaks it down quickly, but also is unable to make it’s own due to metabolic deficiencies. This is more likely to become a problem if a diet that is generally low in protein is fed because the arginine content is also likely to be low.
The amino acid taurine is made from the sulphur amino acids methionine and cystine and is needed for eyesight, heart function, bile formation and reproduction in female cats. Cats are not able to make enough taurine themselves and rely on it being provided in food. Nearly all taurine comes from meat, poultry or shellfish, so cats should never be fed as vegetarians. Cats also need a dietary source of the essential fatty acid arachadonic acid as they are unable to make enough of their own. Arachadonic acid is found in animal fat sources only and is another reason why cats must not be fed as vegetarians.
Vitamin A is made in most species inside their bodies. Cats cannot make vitamin A, so it must be provided in the diet, either naturally or as a supplement.
Niacin, or nicotinic acid, is a B-complex vitamin which, in dogs, can be made using the amino acid tryptophan. The enzyme system responsible for this conversion does not work well in the cat and it also needs much more of this vitamin than the dog. The nutritional needs of any one individual cat can also be affected by its lifestyle (indoor or outdoor), its age or reproductive state (e.g. in-kitten or neutered) and cat foods are available which take these factors into account.
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