Abstract
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 indentical 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. There were no statistically significant differences between the two groups in body weight change, daily and cumulative nitrogen intake, urinary and fecal nitrogen excretion, and nitrogen balance, colonic bursting strength, (215.8 ± 7.0 mm Hg for TEN, 203.3 ± 4.6 for TPN), colon anastamosis hydroxyproline (2.15 ± 0.20 μg/mg for TEN, 1.94 ± 0.13 μg/mg for TPN) skin incision breaking strength (Fresh, 100 ± 6.1 g for TEN, 105 ± 5.7 g for TPN) and after formalin fixation 379 ± 27 g for TEN, 370 ± 23 g for TPN and hydroxyproline content of reparative tissue in the SC sponges (1259 ± 92 μg/100 mg sponge for TEN, 1312 ± 86 μg/100 mg sponge for TPN).
In conclusion, the overall utilization of high BCAA concentration nutrients of very similar composition infused enterally (TEN) or intravenously (TPN) are equivalent and the route of their administration does not influence cutaneous, subcutaneous, and colonic wound healing, weight change, or daily and cumulative nitrogen balance following acute surgical stress. (Journal of Parenteral and Enteral Nutrition
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