Prolongation of the Life Span of Rats by Bulk-Formers in the Diet

Abstract
The effects of feeding a low residue diet and this diet with added bulk-formers on the growth and longevity of 212 Wistar rats were determiend. The bulk-formers used included alfalfa stem meal, psyllium seed husks, ground kapoc, cellulose flour, ground cellophane and granular karaya gum. The effects of feeding the different diets ad libitum or with intermittent fasting, and of feeding the low residue or bulky diets early or late in life were simultaneously investigated. The results indicated a sex difference in the effect of bulkformers. In rats fed ad libitum the life span of both sexes was increased by 10% and 25% (added) relatively smooth bulkformers but the life span of females was not increased by 10% cellulose flour or ground cellophane. The results differed in intermittently fasted rats and in those fed different amounts of bulk during different periods of life. No impairment of skeletal growth was produced when diets with 10% bulk-formers were fed only after the rats became 42 or more days old. A diet with 25% relatively smooth bulk prolonged the life span as much as fasting 1 day in 3, which was previously found to be the optimum amount of intermittent fasting for rats. Contrary to findings in previous studies, no cecal ulceration was found in 6 rats fed 10% to 25% granular karaya gum.