Assessment of the rate of solid-phase gastric emptying in ponies by means of the C-13-octanoic acid breath test: a preliminary study

The aim of this study was to assess the feasibility of applying the C-13-oc tanoic acid breath test for assessment of gastric emptying in ponies by inv estigating the pattern of C-13 enrichment in breath following the administr ation of a test meal +/- C-13-octanoic acid. After a 14 h fast, the ponies received either no meal (Test I) or a standardised test meal labelled with 0 mg (Test 11), 125 mg (Test III), 250 mg (Test IV) or 500 mg (Test V) C-13 -octanoic acid. For each test (I-V), exhaled breath samples were collected in duplicate at 1 h and immediately before ingestion of the test meal and a t frequent intervals thereafter for 12 ll, Breath samples were analysed by continuous flow isotope ratio mass spectrometry, Three indices of breath C- 13-enrichment were computed; half dose recovery time (t1/2), gastric emptyi ng coefficient (GEC) and time to peak breath C-13-enrichment t(max), For Te sts I and II, the ratio of (CO2)-C-13:(CO2)-C-12 remained stable for the du ration of the sampling period. For Tests III, IV and V, an increase in the ratio of (CO2)-C-13:(CO2)-C-12 was detected. The test was reproducible with in individuals, and intersubject variation was low, Further validation stud ies of this noninvasive technique are justified.