WHAT IS THE ROLE OF TAURINE IN CATS ?
What is taurine ?
Taurine has been discovered in 1827, in the bull, hence its name. It is an amino-acid that can be synthetized from sulphurated amino-acids: methionine and cysteine. Contrary to classical amino-acids that are included in fairly complex proteins, taurine stays under free form. The following tissues are specially rich in taurine: muscles (including heart), the central nervous system, the retina of the eye…
First well-known role of taurine
In cats, taurine is indispensable for the formation of biliary salts, that are necessary for the good digestion of fats in the small intestine. Contrary to other species, the cat cannot use another amino-acid than taurine for this function. Consequently, the cat has got an important requirement for taurine that cannot be met by the hepatic synthesis from sulphurated amino-acids present in the diet. The cat relies on its dietary intake of taurine. This is an example of the cat's dependance towards animal ingredients, because taurine is not found in vegetable ingredients.
Other physiological roles of taurine
Taurine and vision
Taurine is indispensable to maintain the completeness of the retina of the eye ; (the retina is the membrane that covers the fundus of the eye, on which pictures are formed). In the retina, there is 100 to 400 times more taurine than in the blood. Since 1975, one knows that in the cat, a chronic deficiency of taurine induces a progressive degeneration of the retina, leading to a total blindness within 2 years. The correction of the diet allows to stop the evolution, but the lesions are not reversible.
Taurine and cardiac function
Taurine represents 50 % of the free amino-acids in the cardiac muscle. Rather recently (1987), a relationship has been established between taurine deficiency in the diet and the occurence of specific cardiac troubles. The affected animals present an important dilatation of the left part of the heart. The addition of taurine in the diet is enough to restore a normal situation.
Taurine and reproduction
Taurine deficiency has multiple consequences on the reproduction function : lack of fertility, foetal resorptions, abortions, abnormalities in new-born kittens, growth diseases in kittens…
Taurine is indispensable for the development and the integrity of the nervous system. One knows also that it has a protective effect on cellular membranes. It plays a role in the blood coagulation mechanisms, immunitary reactions, protection of the respiratory tissue…
Diagnosis of a taurine deficiency in the cat
In case of taurine deficiency, the degree of severity of the lesions in the retina and the heart is very different according to the individuals. Some animals do not even show any clinical sign. Then, when a taurine deficiency is suspected, it can only be confirmed by the dosage of taurine in the whole blood. If the level is too low, the diagnosis is done.
Prevention of a taurine deficiency in the cat
Following the recognition of the role of taurine in some cardiac diseases, its optimal level of incorporation in the diet has been revised upwards. The scientists all agree today to recommend a minimum of 1000 mg of taurine per kg of dry matter in dry products, or 0,1 %, and twice more in canned products, or 0,2 %. Effectively, the biological availability of taurine varies according to the type of diet fed to the animal.
This taurine supplementation is not done in dogfood. It is one of the reasons that explain why we must not feed a cat with a dogfood during a long time.
To prevent any risk of taurine deficiency, Royal Canin adds much more taurine than the minimum recommended in all its cat products. Feline Nutrition and Felistar products contain at least 0,15 % of taurine, up to 0,25 % in kitten products.
Donated by the Borg Cardona and Co. Ltd. visit Borg Cardona website