Motility of the large intestine and flow of digesta in pigs.

The motor function of the large intestine of pigs is incompletely understood. Here the ileo-caecal-colonic motility is investigated by means of chronically implanted extraluminal strain gauge transducers and simultaneous videofluoroscopy in six pigs. Motility parameters were evaluated by computer and manually. The dominant feature of the ileal motility were aborally propagating giant contractions (velocity: 3.9 (0.7) cm sec(-1)) occurring at intervals of 7-12 minutes. They pushed the ileal digesta into the caecum. Despite a fed-state, migrating motor complexes occurred at intervals of 131.5 (8.1) minutes consisting of repetitive peristaltic waves. The motility of the caecum showed clustered contractions representing haustral movements. Transfer of caecal digesta and gas into the colon was caused by peristaltic contractions. The motility of the proximal colon was characterised by long peristaltic waves resulting in a rapid aboral transport of gas and a slow aboral flow of digesta. The propagation velocities along the centripetal and centrifugal loops of the colonic coil were 2.8 (0.6) and 5.7 (0.8) cm sec(-1), respectively. About half of the colonic waves were coordinated with the ileal giant contractions and the caecal peristaltic waves. The contraction parameters showed pronounced differences between the ileum and large intestine. The contraction rise time of the caecal and colonic contractions was about twice that of the ileal contractions (5.1 (0.2) and 4.4 (0.6) seconds versus 2.2 (0.1) seconds). Consequently, the maximal frequencies of the caecal and colonic contractions were about half compared with the ileal contractions (5.3 (0.4) and 6.1 (0.1) contractions min(-1) versus 11.8 (0.3) contractions min(-1)). Results show that the contractile patterns and motor functions of the individual intestinal segments differ markedly.