The influence of dietary fibre on secretory activities of the alimentary tract

SoME years ago, during an investigation of the influence of rate of growth on the development of rickets in sheep, parallel studies were undertaken using the rat.Owing to the difficulty of obtaining from rats blood samples sufficiently large for phosphatase determination, and having in mind the observations of Heymann [1930; 1931; 1933] on the faecal excretion of phosphatase in rickets, the con- centration of this enzyme in the faeces of the rats was determined.It was observed that wide fluctuations occurred in the elimination of phosphatase when animals were transferred from one diet to another.This was elpecially noticeable in the case of weanling rats transferred to stock diets.The t6ntative conclusion was drawn that the augmentations in excretion were caused by ircreased bulk of ingesta which, it was felt, must increase secretory activity within the alimentary tract.The large increases observed for the weanlings were, no doubt, the result Of the sensitivity to stimulus of an immature tract accustomed to a diet mainly of milk.These results were not published.More recently investigations have been in progress in which domestic animals received larger quantities of fibre in the diet than is customary, and certain questions regarding the influence of bulk of ingesta on activities within the alimentary tracts were raised.The connexion between this problem and earlier investigations led to the undertaking of the present study.EXPERIMENTAL Six virgin female albino rats aged 105-140 days and weighing 199-225 g.were housed in pairs in three Hopkins metabolism cages which permit of the separate collection of urine and faeces.The aaiumals were fed daily at 10 awm.after collection of the urine, faeces and unconsumed food.Food and distilled water were offered in excess of appetite.The composition of the low fibre basal diet is recorded in Table1. Table 1.Low fibre diet g. g.