Application of the lactose 13C-ureide breath test for measurement of equine orocaecal transit time.

This research investigates the use of lactose 13C-ureide breath test (LUBT) in order to measure the orocaecal transit time (OCTT) – the period it takes for food to travel from the mouth to the caecum in the horse’s digestive system. The main finding is that this approach can be used as a noninvasive, effective measure of equine OCTT, and when combined with the 13C-octanoic acid breath tests, it also provides information on small intestinal motility.

Objective and Methodology of the Research

The main objectives of this research were to:

• Assess the effectiveness of LUBT in healthy horses by comparing results of induced versus non-induced test protocols;
• Deploy a new dual stable isotope breath test (lactose 13C-ureide and 13C-octanoic acid) for measuring gastrointestinal transit.

In their methodology, the researchers executed induced and non-induced LUBTs on three healthy mature horses in a random order using a standard test meal and protocol. They also performed combined LUBT and 13C-octanoic acid breath tests on four horses on four occasions at weekly intervals. The data from the expiratory isotopic recovery were modeled to derive gastrointestinal transit information such as the gastric emptying data, small bowel transit times, and caecal transit parameters.

Results Obtained and Conclusions

The results showed that the induction protocol for the LUBT significantly increased the rate and magnitude of expiratory 13CO2. The averages for OCTT, caecal lag phase (the delay before the cecum starts to process the food), and caecal t1/2 (the time taken for half the contents of the cecum to be emptied) using the induced LUBT were also recorded.

Dual stable isotope tests, meanwhile, resulted in the production of two discrete peaks in expiratory 13CO2 in 15 out of 16 tests. This allowed for the calculation of gastric t1/2, OCTT, and small bowel transit (SBT) parameters. Based on their findings, the researchers concluded that the induced LUBT provides a reliable noninvasive measure of equine OCTT and, when paired with the 13C-OABT, can give additional information about intestinal motility.