The bile acids of cats, as well as dogs, are conjugated in liver almost exclusively with taurine ( 12, 13). They also found that antibiotic ingestion reduced fecal bile acid excretion and fecal cholyltaurine hydrolase activity.

Kim and colleagues ( 8) observed marked improvement in the taurine status of cats given antibiotics. Morris and others ( 11) postulated that dietary need for taurine was largely dependent on gastrointestinal microbial-mediated loss of taurine. Dietary taurine requirements were lowest with purified ingredients and greatest with heat-processed canned foods. Differences in dietary matrix were observed to vary dietary taurine requirement of cats over a 6-fold range ( 10). Heat processing ( 6), sources and amount of dietary fiber ( 7), and protein source, quantity, and quality ( 8, 9) are among factors shown to significantly impact circulating taurine concentrations in cats. Several hypotheses about dietary factors causing the DCM in cats were investigated during the following 15 years. Others had shown that dietary taurine was essential for normal growth, development, and reproduction of cats ( 5). Inadequate synthesis of taurine from the dietary sulfur amino acids (SAA), methionine and cysteine, was known to cause an irreversible retinopathy in cats ( 4). At the time, research had already shown that taurine was an essential nutrient for cats ( 3). The condition was uniquely associated with low plasma taurine concentrations and reversed in many cats by oral taurine supplementation and change of diet ( 2). Heart failure resulting from a dilated cardiomyopathy (DCM) and induced by feeding certain commercially available diets was first described in domestic cats in 1987 ( 1). Taurine status and dietary SAA requirements of dogs may substantively depend on taurine loss mediated by intestinal microbiota. Antibiotic administration restored plasma and muscle taurine to initial concentrations and halved fecal bile acid excretion by dogs of both groups.Ĭonclusions: Blood taurine concentration may not be a sensitive indictor of taurine depletion caused by low intake of bioavailable SAA in dogs, especially in large dogs. Concentrations of taurine in muscle were lower ( P < 0.01) and fecal bile acids greater ( P = 0.001) in large than small dogs. Results: When given for 36 weeks the lowest SAA diet, 3.4% methionine and 2.9% cystine, taurine concentrations in whole blood were not different between groups, while taurine in plasma declined ( P < 0.05) in large but not in small dogs, and taurine in biopsied muscle decreased ( P < 0.05) by 50% in large and by 37% in small dogs. Fecal bile acid excretion before and after antibiotics administration were quantified.

Taurine concentrations were determined every 2–4 weeks in venous blood and voided urine and every 4 to 16 weeks in biopsied semimembranosus muscle. After receiving the final diet for 44 weeks, all dogs were orally administered a mixture of ampicillin, neomycin sulfate, and metronidazole for 12 weeks.

Methods: Adult, male, Beagles ( n = 6 10.1–13.1 kg) and larger mixed-breed dogs ( n = 6 28.5–41.1 kg) were given four dry-expanded diets, whereby each successive diet contained lower protein and/or SAA concentration. Objective: We determined effects of dietary SAA restriction on rate and extent of taurine depletion of blood and skeletal muscle in dogs of two body sizes, and whether oral antibiotic administration affected the taurine depletion and fecal bile acid excretion of the dogs. 3Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO, United Statesīackground: Taurine status is impacted by dietary supply of methionine and cysteine (SAA) and possibly intestinal microbial activity, where plasma and whole blood taurine concentrations are currently used to evaluate taurine status.2Royal Canin SAS Research Center, Aimargues, France.

1Department of Molecular Biosciences, University of California, Davis, Davis, CA, United States.

Taurine deficiency in cats causes