The ‘minute Rhythm’ Incidence in the Ovine Abomasal Antrum and Small Intestine

To characterise further the ‘minute rhythm’, six healthy rams were equipped with serosal electrodes sewn onto the abomasal antrum and the small bowel. The experiments were performed before and after feeding. Food was offered during phase 2a or 2b of the migrating motility complex. The ‘minute rhythm’ incidence and coordination were assessed during four 5-minute observation periods. In the duodenal bulb and duodenum, the pattern was observed more frequently than in other segments examined. During phase 2b, the ‘minute rhythm’ incidence was often more frequent than during phase 2a of the migrating motility complex. Feeding increased significantly the ‘minute rhythm’ incidence, but these alterations were more evident during first two observation periods. In the jejunum, duration of one ‘minute rhythm’ episode was longer than in more proximal segments. In the more distal jejunal recording site the ‘minute rhythm’ was often absent. The pattern was well coordinated mostly in the antroduodenum and its propagation velocity was the highest also in the upper small bowel. It is concluded that the ‘minute rhythm’ incidence, form, and coordination depended upon the feeding conditions, intensity of intestinal motility and the gastrointestinal segment.