THE EFFECT OF CALORIC LOAD AND NUTRIENT COMPOSITION ON INDUCTION OF SMALL-INTESTINAL SATIETY IN DOGS

The influence of caloric load and nutrient composition on small intest inal satiety was investigated in six dogs with chronic esophageal fist ulas. Dogs received small bowel infusion of a mixed nutrient liquid me al, a fat, carbohydrate, and a protein solution over two hours. Each i nfusion was given over a range of caloric densities which represented between 0 to 20% of the total 24 h caloric requirement for each animal . Satiety was measured by sham feeding at the end of the infusion. Inf usion of 0.25 cal/ml (equivalent to 5% of the 24 h caloric requirement ) of a liquid mixed nutrient meal (Isocal(R)) significantly suppressed sham feeding (volume sham fed: control 265 +/- 28 ml/min; Isocal 0.25 cal/ml 218 +/- 52 ml/min, p < 0.05). Oleate and dextrose polymer also significantly reduced sham feeding at a caloric concentration of 0.25 cal/ml (volume sham fed: control 265 +/- 28 ml/min; oleate 112 +/- 28 ml/min; oleate 112 +/- 9 ml/min; dextrose polymer 190 +/- 11 ml/min), whereas peptone did not significantly Suppress sham feeding until a s olution with 0.5 cal/ml was given. These studies demonstrate that calo ric load of intestinal nutrients must reach a threshold to produce sat iety in sham feeding dogs. The threshold caloric load is different for the three nutrient groups, with fats requiring the lowest caloric loa d to produce satiety. These provide insight into the mechanisms by whi ch small intestinal signals might contribute to regulation of the inte r-meal interval. (C) 1997 Elsevier Science Inc.