Infusion of enteral vs parenteral nutrients using high-concentration branch-chain amino acids: effect on wound healing in the postoperative rat.

Starting total parenteral nutrition (TPN) the day after acute surgical stress has beneficial effects on body weight, nitrogen balance, and colonic anastomosis bursting pressure in normally nourished rats. In view of the reported favorable utilization of high-concentration branch-chain amino acids (BCAA) following severe stress, we compared enteral (TEN) to parenteral (TPN) nutrient infusions containing increased BCAA starting the day of operation. Twenty-four male Sprague-Dawley rats, in two groups paired by weight under IP pentobarbital anesthesia underwent jugular vein catheter (CVP) insertion, laparotomy, gastrostomy, colon anastomosis, dorsal skin incision and SC polyvinyl alcohol sponge insertion. The rats were maintained for 6 days with continuous IV infusion in the TPN group (gastrostomy plugged) and continuous gastric infusion for the TEN group (CVP plugged). Urine and feces were collected daily. The infusions contained 1000 to 1002 Kcal, 847 to 845 nonprotein Kcal, 38 to 39 g of amino acids, 206 to 209 g of carbohydrates, and 2.8 to 2.9 g of rat per liter in the TEN and TPN, respectively, with identical ratios of dietary essential amino acids to nonessential amino acids (52/48), and 28.34% BCAA in the TPN and 33.10% BCAA in the TEN. There were 491 mg/100 mL of glutamine in the TEN and 170 mg of glutamic acid in the TPN. Amino acids were infused at 8.59 g/kg per day for TEN and 8.34 g/kg per day for TPN. The vitamins, minerals, and trace minerals were essentially the same in the TEN and TPN except for the absence of iron, iodine, selenium, and molybdenum in the TPN.(ABSTRACT TRUNCATED AT 250 WORDS)