Duodenal osmoregulation after total parenteral nutrition in neonatal piglets

The physiologic effects of intestinal rest on the efficiency of gastroduodenal osmoregulation of hypertonic and hypotonic carbohydrate meals were studied in neonatal piglets 3 to 5 days old. Sixteen piglets underwent laparotomy, gastrostomy, and end jejunostomy just distal to the ligament of Treitz. Sixteen littermates had insertion of a central venous catheter and received 2 weeks of total parenteral nutrition (TPN) before laparotomy, gastrostomy, and end jejunostomy. Experiments were performed 2 days after laparotomy in all groups. Each piglet received intragastric infusions of two test meals (25 ml/kg), half the pigs receiving glucose (494 +/- 11, 147 +/- 3 mOsm/L) and half mannitol (493 +/- 11, 150 +/- 4 mOsm/L) (SD). Gastric samples and jejunal effluent were collected every 30 minutes for 2 hours. TPN did not influence duodenal osmoregulation. Significant changes in osmolality occurred during duodenal transit after all meals, and these changes were similar for all groups. However, jejunal osmolality did not approach basal levels until late in the observation period. These results demonstrate significant but incomplete intraduodenal osmoregulation of carbohydrate meals in neonatal piglets that is unaffected by 2 weeks of intestinal rest.