Intestinal absorption of peptide enteral formulas in hypoproteinemic (volume expanded) rats: a paired analysis

Previous studies have confirmed the improved tolerance of a peptide enteral compared to standard enteral alimentation in hypoalbuminemic, critically ill patients. Animal studies, including hypoproteinemic, volume-expanded rats, demonstrated that the protein hydrolysate of a peptide enteral formula was responsible for the enhanced absorption. The purpose of this study was to determine whether the composition of small MW peptides (protein hydrolysate) in two commercially available peptide enteral formulas would affect the rate of intestinal absorption and albumin clearance in intact jejunal loops before and during hypoproteinemia induced by iv infusion of Tyrode's solution in Sprague-Dawley rats. Net transmucosal water movement was calculated using a volume recovery method; albumin clearance was calculated using iv radiolabeled albumin. We studied three groups of animals during luminal perfusion with either Tyrode's solution, diet A containing 21% peptides, or diet B containing 56% peptides. When compared to luminal perfusion with Tyrode's solution (control animals), both diets significantly enhanced net transmucosal water absorption before volume expansion (p less than .05). With the induction of hypoproteinemia, diet B continued to stimulate water absorption when compared to control animals (p less than .01). Luminal perfusion with diet A failed to attenuate net water secretion induced by hypoproteinemia. Capillary and mucosal albumin clearance was similar for all groups studied. These findings suggest the percentage of small MW peptides may affect the rate of intestinal absorption in patients with acute kwashiorkor-like hypoalbuminemia.