Use of 13C-acetate breath test for assessment of gastric emptying in horses.

This study aimed to establish and standardize a breath test that uses 13C-acetate in a liquid diet for evaluation of gastric emptying in horses. Seven adult healthy thoroughbreds were used in this study. They were given 13C-acetate (125 mg, 250 mg, or 500 mg) in a test meal (2000 ml liquid diet) via an intranasal catheter. 13C concentrations in the exhaled CO2 were measured in samples taken before and after test meal administration using an infrared absorption spectroscope. In the 500 mg 13C-acetate group, Delta13CO2 showed a steep gradient immediately after meal administration compared to the 125 mg and 250 mg groups. Therefore, t(max) in the 500 mg group was easier to determine than in the 125 mg and 250 mg groups. In the 500 mg group, GEC, half-empty time (t1/2), calculated t(max) (t(lag)), and t(max) were 1.95 +/- 0.28 (mean +/- SD), 229.2 +/- 57.0 (min), 139.2 +/- 22.2 (min), and 124.0 +/- 28.4, respectively. Differences in CV observed in the 500 mg group were lower than those in the 125 mg and 250 mg groups. This study demonstrates that the 13C-acetate breath test is useful for evaluating gastric emptying in horses since it is non-invasive and does not require set up of special facilities or equipment. Optimum evaluation of gastric emptying in horses can be achieved with 500 mg of 13C-acetate given in a liquid diet.