INTESTINAL OXYGENATION AND MUCOSAL PERMEABILITY WITH LUMINAL MOTHERS MILK IN DEVELOPING PIGLETS

We have previously observed a developmental difference in mucosal perm eability (i.e. the younger the animal, the greater the increase in per meability) after exposure to luminal nutrients derived from cow's milk -based infant formulas. There has been tremendous speculation and some clinical evidence that mother's milk may be protective against mucosa l injury in developing intestine. In this study, we hypothesized that instillation of sow's milk into the intestinal lumen of developing pig lets would cause no differences in either intestinal metabolic demand (oxygen uptake) or mucosal permeability among age groups. Intestinal b lood how (total and fractionated), arteriovenous oxygen content differ ence, venous pressure, and capillary pressure were measured, and vascu lar resistance and oxygen uptake were calculated, after 30 min of intr aluminal instillation of predigested and solubilized sow's milk in la- old, 3-d-old, 2-wk-old, and 1-mo-old piglet jejunoileum. In a separate group of animals, plasma-to-lumen clearance of chromium-51 EDTA was e valuated during luminal perfusion with digested and solubilized sow's milk in 1-d-old, 3-d-old, and I-mo-old piglet jejunoileum. Intestinal oxygen uptake was similar among age groups of developing piglets, but EDTA clearance was significantly higher for intestinal segments perfus ed with sow's milk in 1-d-old, compared with older, animals. Thus, lum inal perfusion with predigested and bile acid-solubilized sow's milk i n 1-d-old piglet jejunoileum, compared with perfusion in older piglets , causes increased mucosal permeability in 1-d-old intestine, but this increased permeability is not due to increased intestinal oxygen upta ke (i.e. increased metabolic demand).