EFFECTS OF REDUCING THE STARCH CONTENT IN OAT-BASED DIETS WITH CELLULOSE ON JEJUNAL FLOW AND ABSORPTION OF GLUCOSE OVER AN ISOLATED LOOP OFJEJUNUM IN PIGS

Four pigs fitted with two sets of re-entrant cannulas in the upper jej unum were used to study the effect of two oat-flour (F)- and oat-bran (B)-based diets without or with (FC and BC respectively) addition of 1 48 g wood cellulose/kg on jejunal flow and absorption of glucose over an isolated loop of jejunum. Mean transit time (MTT) of flow from the proximal re-entrant cannula increased from approximately 1.5 h with di et F to 2h when feeding diet BC. Both the replacement of oat flour by oat bran and the supplementation of the diets with cellulose led to a significantly longer MTT for dry matter and the carbohydrates, except that cellulose did not have a significant effect on the MTT for the to tal non-starch polysaccharides. Only the addition of cellulose signifi cantly delayed gastric emptying of the added liquid-phase (Polyethylen e glycol 4000) and solid-phase (Cr2O3) markers, whereas no effect of t he oat source used was seen. Feeding diets with a higher level of diet ary fibre (DP) and lower content of starch, obtained by substitution w ith cellulose or by feeding oat bran instead of oat flour, reduced the recovery of starch from an isolated loop of jejunum. Consequently, th e quantitative absorption of starch was not significantly different be tween diets when starch was related to the recovery of external marker s. However, when related to the recovery of arabinoxylan (AX) there wa s a significantly lower absorption of starch from the bran-based diets in comparison with the flour-based diets. The capacity to digest and absorb the large quantities of starch entering the duodenum after a ca rbohydrate-rich meal appears to be the limiting factor for absorption in the upper jejunum. Therefore, any effect of DF on the rate of absor ption of glucose is presumably an effect on gastric emptying rather th an displacement of the site of starch absorption in the small intestin e. Dietary fibre: Gastric emptying: Glucose