Gastrointestinal growth in rats as influenced by indigestible polysaccharides and adaptation period.

Hypertrophy of the small intestinal tissue evolved during the initial 9 days in rats fed pectin or guar gum. Hypertrophy of the caecal and colonic tissue continued beyond day 9. Caecal hypertrophy was observed in rats fed pectin, guar gum or resistant starch, while colonic hypertrophy was observed only in rats fed pectin or resistant starch. There is a time lag in the adaptive response of the caecum and colon as compared with the small intestine, at least for dietary polysaccharides. This time lag is suggested to be related to the time required for the microflora to adapt to the dietary PS.