Effects of dietary fat and L-carnitine on plasma and whole blood taurine concentrations and cardiac function in healthy dogs fed protein-restricted diets

Objective-To evaluate plasma taurine concentrations (PTC), whole blood taur ine concentrations (WBTC), and echocardiographic findings in dogs fed 1 of 3 protein-restricted diets that varied in fat and L-carnitine content. Animals-17 healthy Beagles. Design-Baseline PTC and WBTC were determined, and echocardiography was perf ormed in all dogs consuming a maintenance diet. Dogs were then fed I of 3 p rotein-restricted diets for 48 months: a low-fat (LF) diet, a high-fat and L-carnitine supplemented (HF + C) diet, or a high-fat (HF) diet. All diets contained methionine and cystine concentrations at or above recommended Ass ociation of American Feed Control Officials (AAFCO) minimum requirements. E chocardiographic findings, FTC, and WBTC were evaluated every 6 months. Results-The FTC and WBTC were not significantly different among the 3 group s after 12 months. All groups had significant decreases in WBTC from baseli ne concentrations, and the HF group also had a significant decrease in PTC. One dog with PT and WBT deficiency developed dilated cardiomyopathy (DCM). Taurine supplementation resulted in significant improvement in cardiac fun ction. Another dog with decreased WBTC developed changes compatible with ea rly DCM. Conclusions and Clinical Relevance-Results revealed that dogs fed protein-r estricted diets can develop decreased taurine concentrations; therefore, pr otein-restricted diets should be supplemented with taurine. Dietary methion ine and cystine concentrations at or above AAFCO recommended minimum requir ements did not prevent decreased taurine concentrations. The possibility ex ists that AAFCO recommended minimum requirements are not adequate for dogs consuming protein-restricted diets. Our results also revealed that, similar to cats, dogs can develop DCM secondary to taurine deficiency, and taurine supplementation can result in substantial improvement in cardiac function.