Intraluminal lipids modulate avian gastrointestinal motility.

Infusion of lipids into the ileum delays gastric emptying and intestinal transit time in some species. The aim of this study was to characterize the actions of intraluminal lipid infusion on gastrointestinal electrical activity in chickens. Animals were prepared for electromyography with chronic electrodes in stomach, duodenum, and small intestine. Two catheters were chronically placed in the esophagus and ileum to infuse equimolar doses of either oleic acid (OA) or triolein (TO). Both OA and TO, esophageally infused, inhibited the frequency of the gastroduodenal cycle and increased the frequency of antiperistaltic spike bursts in the duodenum. Ileal infusion of OA, but not of TO, produced the same effects. Both esophageal and ileal OA infusion increased the duration of the migrating myoelectric complex (MMC) and decreased the speed of propagation of phase III. In conclusion, intraluminal infusion of lipids modulates gastrointestinal motility by decreasing the frequency of the gastric cycle, increasing duodenogastric refluxes, and elongating the MMC. These actions could delay gastric emptying and increase transit time, which suggests the presence of an "ileal brake" mechanism similar to that described in mammals.