Low levels of de novo synthesis have also been reported in humans, Old World monkeys, rabbits, and guinea pigs. 63 The cat is not unique in its limited capacity for taurine synthesis. In addition, the competing pathway of cysteine catabolism, which produces pyruvate and sulfite rather than taurine from methionine and cysteine, is very responsive to increased cysteine concentrations (see Figure 12-1). 62 This inability is partially the result of the cat’s low activity of two enzymes that are essential for taurine synthesis: cysteine dioxygenase and cysteine sulfinic acid decarboxylase. Melody Foess Raasch DVM, in Canine and Feline Nutrition (Third Edition), 2011 CATSĬats are able to synthesize only small amounts of taurine and so require a dietary source of taurine to meet daily needs. For instance, perinatal taurine depletion alters learning, memory, and neural control of blood pressure in adult life, whereas taurine supplementation prevents or improves some neurological disorders. Because de novo synthesis of taurine is relatively low in the brain, exogenous taurine is needed for appropriate development and adult functions of the brain. During the postnatal period, GABA gains dominance along with glycine as central inhibitory transmitters. During the embryonic and early postnatal life, taurine appears to act as a major inhibitory neurotransmitter/modulator in the brain, having much higher concentrations than GABA in most areas. Studies of synthesis and distribution show that taurine is present in the brain of the early embryo and is differentially distributed. It plays a role in neurotransmission, although the brain does not appear to have a specific taurine receptor. Taurine is present in the brain, where it appears to be involved in many functions from conception onward. Sanya Roysommuti, James Michael Wyss, in Bioactive Nutraceuticals and Dietary Supplements in Neurological and Brain Disease, 2015 Abstract 30 As taurine is abundant in animal tissue, the need to synthesize taurine would not be necessary in the cat's normal required metabolic pathways. Taurine deficiency in the cat is well documented, resulting in dilated cardiomyopathy, central retinal degeneration, and reproductive failure. Loss of taurine in a diet due to processing effects Loss of taurine in the enterohepatic circulation associated with increases in bacterial flora that degrade taurine Whereas dogs are able to synthesize sufficient taurine from cysteine, cat taurine synthesis is negligible due to low activity of two enzymes in the pathway.
Cats and dogs are only able to use taurine to conjugate bile acids. 29 Many mammals are able to use either glycine or taurine for bile acid conjugation. Taurine serves numerous important functions, including osmoregulation, calcium channel modulation, antioxidant activity, and bile acid conjugation. The highest concentrations of taurine are found in the heart, muscle, brain, and retina.
TAURINE DOGS FREE
Taurine is a beta-sulfonic amino acid that is not used in protein synthesis but is found as a free amino acid in tissues.