Intestinal absorption of elemental and standard enteral formulas in hypoproteinemic (volume expanded) rats

We examined the influence of a peptide-based enteral formula and a standard (intact protein) enteral formula on intestinal transcapillary and transmucosal water and protein fluxes during hypoproteinemia induced by plasma volume expansion. In 15 Sprague-Dawley rats, net transmucosal water flux and net transmucosal and capillary albumin clearances were monitored in jejunal loops before and during intravenous infusion (2.5 ml/min/kg) of Tyrodes solution. This procedure resulted in a 60% reduction in plasma protein concentration and net water secretion into the bowel lumen. Luminal perfusion with the peptide-based formula did not modify the magnitude of the reduction in plasma protein concentration, yet dramatically reduced transmucosal and transcapillary albumin clearances (p less than 0.05). In addition, a net absorptive water flux was maintained with the peptide-based formula during volume expansion despite hypoproteinemia. The response to luminal perfusion with the intact protein formula were not different from controls. The results of this study are consistent with previous observations that enteral feeding with a peptide-based formula significantly attenuates the diarrhea associated with acute hypoalbuminemia in the critically ill patient.