The lactose-13C-ureide (L13CU) test, used in humans to measure oro-cecal transit time (OCTT) in breath CO2, was assessed for its suitability in pigs as a noninvasive alternative to intestinal cannulation. The OCTT was determined with the L13CU test in breath and saliva samples when pigs were fed low or high dietary fiber (DF) (low fiber, 2.8% DF; high fiber 6.5% DF) diets, and 24 h after an i.m. injection with either lipopolysaccharide (LPS) or NaCl. The OCTT measured in breath was longer in LF-LPS than in LF-NaCl and HF-LPS groups (3.4 vs 2.9 h; p < 0.05). Additionally, LPS prolonged the OCTT of pigs, and DF prevented this effect. 90 % of OCTT estimates measured in saliva and breath CO2 did not differ. We conclude that the L13CU breath test is useful for determining OCTT in pigs; saliva is generally suitable as a sample matrix for OCTT, but its use requires further validation.
