Burrin D G, Davis T A, Ebner S, Schoknecht P A, Fiorotto M L, Reeds P J, McAvoy S
USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.
Pediatr Res. 1995 May;37(5):593-9. doi: 10.1203/00006450-199505000-00006.
We hypothesized that nonnutrient components, including growth factors, present in colostrum contribute to the stimulation of protein synthesis in colostrum-fed neonatal pigs. We studied neonatal pigs fed mature milk, colostrum, or a formula containing a macronutrient composition comparable to that of colostrum for 24 h. We measured the circulating concentrations of insulin, insulin-like growth factor I, glucose, and amino acids at intervals throughout the 24-h period, after which we measured in vivo protein synthesis using a flooding dose of [3H]phenylalanine. The rates of protein synthesis in several tissues measured after 24 h of feeding were greater than those we reported previously after 6 h of feeding. The acute (within 6 h) stimulation of protein synthesis in visceral and skeletal muscle tissues of neonatal pigs fed milk, colostrum, or formula was primarily influenced by nutrient intake and associated with rapid secretion of insulin. Indirect evidence suggests that intestinal absorption of ingested colostral insulin was minimal. However, the sustained increase in tissue protein synthesis between 6 and 24 h coincided with an increase in circulating insulin-like growth factor I. We found a novel, specific stimulation of skeletal muscle and jejunal protein synthesis in colostrum-fed pigs that can be attributed to some nonnutrient component of colostrum.
我们推测，初乳中含有的非营养成分（包括生长因子）有助于刺激初乳喂养的新生仔猪的蛋白质合成。我们研究了分别用成熟乳、初乳或一种宏量营养素组成与初乳相当的配方奶喂养24小时的新生仔猪。在整个24小时期间，我们每隔一段时间测量胰岛素、胰岛素样生长因子I、葡萄糖和氨基酸的循环浓度，之后使用大剂量的[3H]苯丙氨酸测量体内蛋白质合成。喂养24小时后测量的几个组织中的蛋白质合成速率高于我们之前报道的喂养6小时后的速率。喂养牛奶、初乳或配方奶的新生仔猪内脏和骨骼肌组织中蛋白质合成的急性（6小时内）刺激主要受营养摄入影响，并与胰岛素的快速分泌有关。间接证据表明，摄入的初乳胰岛素的肠道吸收极少。然而，6至24小时期间组织蛋白质合成的持续增加与循环胰岛素样生长因子I的增加同时出现。我们发现初乳喂养的仔猪骨骼肌和空肠蛋白质合成受到一种新的、特异性的刺激，这可归因于初乳中的某些非营养成分。
