242 Effects of different carbohydrate sources on taurine status in healthy Beagle dogs

Abstract

Abstract Consumption of grain-free (GF) diets has recently been linked to canine dilated cardiomyopathy in selected dog breeds. Soluble fiber present in GF carbohydrate sources may be contributing to taurine depletion, thus affecting heart health. The objective of this study was to evaluate the effects of different carbohydrate sources on taurine status in healthy Beagle dogs. Two practical diets sufficient in sulfur-amino acids and taurine were formulated with the same proportion of carbohydrate sources: a grain-based (GB) containing sorghum, millet, and spelt, and a GF containing peas, potatoes and tapioca starch. Twelve Beagle dogs were fed experimental diets for 4-wk in a randomized complete block design. The morning prior to feeding experimental diets (baseline) and two and four weeks after, markers of taurine metabolism were analyzed in blood, urine, and fresh fecal samples. Data were analyzed as a change from baseline in a repeated measures model by GLIMMIX (SAS, version 9.4) in which the main effects of time, diet, and their interaction were evaluated. Greater concentrations of taurine in plasma (158 vs. 117 nmol/mL) and whole blood (254 vs. 234 nmol/mL) were observed during experimental period compared to baseline. An increase in plasma methionine was also observed during experimental period compared to baseline (64 vs. 57nmol/mL). Dogs fed GF exhibited higher plasma taurine concentration compared to those fed GB (181 vs. 138 nmol/mL). There were no significant effects of diet, time, or their interaction on plasma cystine concentration, urinary taurine:creatinine ratio, or total fecal bile acid (BA) excretion (P > 0.05). However, dogs fed GF had greater fecal primary BA (26 vs 14%) as a proportion of total BA compared to those fed GB. This study suggests that GF diets do not impair taurine blood concentration, but the increased proportion of fecal primary BA may decrease recycling of taurine through enterohepatic circulation.