[Effect of casein derived peptides on D-xylose absorption and small intestinal motility in dogs]

The presence of food in the intestinal lumen increases absorption from an isolated intestinal loop, the mechanisms involved are unknown. Casein, and its respective hydrolysate, increased D-xylose absorption in both normal volunteers and experimental animals; this effect was associated with prolonged small intestinal transit time and a decrease of motor activity.

To separate from casein hydrolysate, groups of peptides and to investigate their effects on both D-xylose absorption and small intestinal motility.

Studies were performed on five dogs with a surgically implanted duodenal cannula. Three groups of peptides were separated by means of a Silica Gel 60 column and were continuously infused through the duodenal cannula. After 15 min, 5 g of D-xylose were injected in the duodenum, plasma levels were measured, and the area under the curve was estimated. Motility was recorded by means of infused catheters and external transducers.

Plasma levels of D-xylose were significantly increased during the infusion of one group of peptides compared to the others. In addition, the area under the curve: 3366 +/- 885 mg x min-1 observed with this group was significantly greater than the other two groups: 1432 +/- 183 mg x min-1 and 1137 +/- 280 mg x min-1 respectively. No statistically significant differences in motor activity were observed between the different groups of peptides.

A group of peptides derived from casein was characterized by increasing D-xylose absorption. The presence of beta casomorphines might be the possible mechanism involved.