Changes

==1. What is Taurine?==

==1. What is Taurine?==

Taurine (2-aminoethanesulfonic acid) is a '''naturally occurring sulphonic acid produced in the liver''' as an end product of cysteine metabolism. Taurine is not incorporated into proteins but found free in animal tissues; the highest concentrations are found in brain, heart, and skeletal muscle. Although commonly referred to as an amino acid it lacks a carboxyl group and is not classified as a true amino acid. '''Dogs can synthesise taurine from dietary precursors''' and are typically able produce amounts sufficient to meet daily needs. '''Cats are unable to produce adequate amounts of taurine to meet requirements and pre-formed taurine is required in the diet.'''  

Taurine (2-aminoethanesulfonic acid) is a '''naturally occurring sulphonic acid produced in the liver''' as an end product of [[Methionine and Cysteine - Nutrition|cysteine]] metabolism. Taurine is not incorporated into proteins but found free in animal tissues; the highest concentrations are found in brain, heart, and skeletal muscle. Although commonly referred to as an amino acid it lacks a carboxyl group and is not classified as a true amino acid. '''Dogs can synthesise taurine from dietary precursors''' and are typically able produce amounts sufficient to meet daily needs. '''Cats are unable to produce adequate amounts of taurine to meet requirements and pre-formed taurine is required in the diet.'''  

===Cat:===  

===Cat:===  

Taurine is an essential nutrient in cats due to:  

'''Taurine is an essential nutrient in cats due to''':  

#Reduced activity of hepatic cysteine dioxygenase and cysteine sulphinate decarboxylase activity (two key enzymes in the conversion of cysteine to taurine) as compared with other species<ref>De la Rosa J et al. Metabolism of cysteine and cyteinesulfinate in rat and cat hepatocytes. J Nutr 1987;117:549-558.</ref> and #An obligate loss of taurine in bile acid conjugation. Clinical signs of taurine deficiency may develop in a matter of weeks to months of feeding a deficient diet.  

#Reduced activity of hepatic cysteine dioxygenase and cysteine sulphinate decarboxylase activity (two key enzymes in the conversion of cysteine to taurine) as compared with other species<ref>De la Rosa J et al. Metabolism of cysteine and cyteinesulfinate in rat and cat hepatocytes. J Nutr 1987;117:549-558.</ref> and #An obligate loss of taurine in bile acid conjugation. Clinical signs of taurine deficiency may develop in a matter of weeks to months of feeding a deficient diet.  

==7. Dietary Sources==

==7. Dietary Sources==

Taurine is found in animal proteins, with highest concentrations in skeletal and heart muscle, though concentrations will vary by species<ref name="Spitze">Spitze AR, et al. Taurine concentrations in animal feed ingredients; cooking influences taurine content. JAPAN(Berl) 2003 Aug;87(7-8):251-62.</ref>. Taurine is also lower in dairy and egg proteins and it limited to absent in plant proteins. Vegetarian and Vegan diets will cause taurine deficiency in cats if not supplemented adequately; vegetarian and vegan diets for dogs often contain inadequate sulphur amino acid precursors and are at a high risk for causing taurine deficiency in dogs. Synthetic forms of taurine are available for vegetarian and vegan diets. Diets severely restricted in protein may provide insufficient quantities of amino acids to support adequate taurine production in dogs<ref>Sanderson SL, et al. Effects of dietary fat and L-carnitine on plasma and whole blood taurine concentrations and cardiac function in healthy dogs fed protein-restricted diets. AJVR 2001;62:1616-1623.</ref>.

Taurine is found in animal proteins, with highest concentrations in skeletal and heart muscle, though concentrations will vary by species<ref name="Spitze">Spitze AR, et al. Taurine concentrations in animal feed ingredients; cooking influences taurine content. JAPAN(Berl) 2003 Aug;87(7-8):251-62.</ref>. Taurine is also lower in dairy and egg proteins and it limited to absent in plant proteins. Vegetarian andvegan diets will cause taurine deficiency in cats if not supplemented adequately; vegetarian and vegan diets for dogs often contain inadequate sulphur amino acid precursors and are at a high risk for causing taurine deficiency in dogs. Synthetic forms of taurine are available for vegetarian and vegan diets. Diets severely restricted in protein may provide insufficient quantities of amino acids to support adequate taurine production in dogs<ref>Sanderson SL, et al. Effects of dietary fat and L-carnitine on plasma and whole blood taurine concentrations and cardiac function in healthy dogs fed protein-restricted diets. AJVR 2001;62:1616-1623.</ref>.

Processing and cooking of foods will also influence taurine content and animal requirements. Wet food diets promote higher intestinal bacterial population and will increase loss of taurine in cats<ref>Anantharaman-Barr G, et al. Fecal bile acid excretion and taurine status in cats fed canned and dry diets. J Nutr 1994;124:2546S-2551S.</ref><ref>Kim SW, et al. Dietary antibiotics decrease taurine loss in cats fed a canned heat-processed diet. J Nutr 1996;126:509-515.</ref>; boiling increases meat taurine loss compared to roasting or baking<ref name="Spitze"/>, and dietary fibre content will influence rate of taurine loss<ref name="Torres"/><ref>Stratton-Phelps M, et al. Dietary rice bran decreases plasma and whole-blood taurine in cats. J Nutr 2002;132:1745S-1747S. </ref>. Vegetarian diets are deficient in taurine, in addition to other key nutrients for cats, and should not be fed without proper supplementation.

Processing and cooking of foods will also influence taurine content and animal requirements. Wet food diets promote higher intestinal bacterial population and will increase loss of taurine in cats<ref>Anantharaman-Barr G, et al. Fecal bile acid excretion and taurine status in cats fed canned and dry diets. J Nutr 1994;124:2546S-2551S.</ref><ref>Kim SW, et al. Dietary antibiotics decrease taurine loss in cats fed a canned heat-processed diet. J Nutr 1996;126:509-515.</ref>; boiling increases meat taurine loss compared to roasting or baking<ref name="Spitze"/>, and dietary fibre content will influence rate of taurine loss<ref name="Torres"/><ref>Stratton-Phelps M, et al. Dietary rice bran decreases plasma and whole-blood taurine in cats. J Nutr 2002;132:1745S-1747S. </ref>. Vegetarian diets are deficient in taurine, in addition to other key nutrients for cats, and should not be fed without proper supplementation.