[Changes in electromyogram of the colon related to ingestion of undigestible particles in dogs].

The relationship between undigestible particle intake and myoelectric activity of the colon was examined in three dogs fed with a low-fiber diet alone or with polyethylene particles containing 10 p. 100 and 45 p. 100 of dry matter. When compared to controls colonic electromyograms of dogs fed on polyethylene revealed a 40 p. 100 reduction in long spike bursts (LSBs). The sequences of LSBs propagated over long distances, or MSBs (migrating spike bursts) were unchanged and only the myoelectric activity corresponding to LSBs propagated for very short distances was abolished by polyethylene diets. Concurrently, the percentage of water excreted in the feces was increased. Undigestible and inert particles were thus able to modify the colonic motor profile and to increase the fecal excretion of water. Such effects were similar to those observed with dietary fibers. It is suggested that dietary fiber effects on fecal excretion and colonic motility are partially induced by their mechanical action on the intestinal wall. In addition, the absence of LSBs propagated in both directions and for short distances on the canine proximal and transverse colons seems to be a limiting factor in the movements of water absorption.