[Cecal motility in the rabbit. III. Duality of fecal excretion]

The production of soft pellets (caecotrophs) was studied in conjunction with feeding behaviour, biochemical changes in caecal contents, motility of the caeco-colic region and transit of digesta in the colon in rabbits fed ad lib. or receiving one or two daily meals. Studies were carried out on animals either collared or free in their cages. Ingestion of soft pellets was recorded from electrodes fixed in the esophageal wall. Similar electrodes positioned on the caecum, proximal and distal colon and the fusus coli monitored regional electrical activity. Transit time for the colon was determined using a marker substance PSP. In animals fed ad lib. soft pellets were usually produced in the morning and this occurred 5 to 6 hours after the daily meal in the same animals. In subjects fasted for 15 hours, a daily meal was followed by increase in the volatile fatty acid concentration and decrease in the pH of caecal contents. Irrespective of the regimen the production of soft pellets coincided with a decrease in motility of both caecum and proximal colon and an increase in that of the distal colon. The transit time for the colon was 1.5 to 2.5 times faster for the production of soft than for the production of hard pellets.