WEB Vetnews May 2015

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Why do dogs and cats need protein? The truth is that dogs and cats do not need any protein in a healthy state at all. What they do need is the building blocks of proteins. Even if animals ingested their exact daily requirements of protein in their diet, their alimentary tract would still break the proteins down to individual amino acids through the process of digestion.

O nce absorbed, these amino acids are requires or, if in excess, are utilised for energy. There are 22 amino acids that their bodies require. They can synthesise 12 of them. The remaining ones, essential amino acids, must be ingested. Under certain conditions of disease and stress other amino acids can become conditionally essential. During liver disease, the animals ability to synthesise amino acids and proteins may become severely diminished. Proteins are used Dr Martin de Scally reconstituted in the cells of the body to the exact proteins the animal

the head, spine, shoulder blade and hip area. Sometimes these animals even have excess body fat, this is a condition called sarcopaenic obesity. The actual protein requirement of the cat is higher than that of the dog. This is a result of cats’ greater need for protein for the maintenance of normal body tissues and the inability to down-regulate certain catabolic enzymes in the liver used to convert protein to energy, regardless of what other source of energy are provided in the food (fat, carbohydrate). The metabolisable energy of protein in dogs’ and cats’ diets is 3.5-4 kcal/g, approximately the same amount of energy supplied by dietary carbohydrate. Animals are unable to store excess amino acids; they are either used directly for energy or are converted to glycogen and fat for storage. As mentioned earlier, animals also gain important by-products when proteins are broken down for energy. Another example of this is the molecule, phosphotidyl choline, which protects an animal’s biliary tract from the caustic action of its own bile. Bile is important in food digestion and if the biliary tract, which is also food, is not adequately protected, biliary tract damage will ensue. The amount of protein that an animal needs to ingest, in order to obtain adequate or optimal amounts of essential amino acids and energy,

carnivorous animals, are well adapted to digestion of meat sources, which contain all their essential amino acids. An alternative way is to supplement food sources that contain inadequate amounts of these essential amino acids. The most well known example of this is taurine supplementation to non-meat based cat foods. As a general rule, the further a diet is from an animal’s natural diet, the more areas it will need supplementing and the more chance there is for something to be overlooked. This applies to other essential nutrients such as essential fatty acids as well. Deficiencies, such as taurine deficiency, caused heart failure in many cats before the dogs and cats actually have the highest requirements of essential amino acids. The best examples of inadequate essential amino acid and caloric ingestion can be seen in older animals, where the shapes of their bones start to be visible because of a loss of muscle mass. The body will utilise its own muscle mass for essential amino acids if ingestion of these nutrients is inadequate. This loss of lean muscle mass is best seen over cause was linked to a dietary deficiency of this essential amino acid in this species. Kittens, puppies and aging

in the animal as structural components in skin, hair, muscle and organs. They are the major components of enzymes and some hormones essential for

maintaining life. Proteins are able to provide carnivorous animals with energy. They also form a vital part of an animal’s immune system. The by-products of protein metabolism yield other essential components such as L-carnitine and glutathione. The most consistent way of ensuring an adequate amount of all the essential amino acids is to ingest adequate amounts of food sources that contain them. Dogs and cats, being

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Mei/May 2015