Bertolo R F, Pencharz P B, Ball R O
Department of Human Biology and Nutritional Sciences, University of Guelph, Ontario, Canada.
JPEN J Parenter Enteral Nutr. 1999 Mar-Apr;23(2):47-55. doi: 10.1177/014860719902300247.
The amino acid requirement profile for infants is different than that for adults and needs to be established; this profile also is different for infants receiving total parenteral nutrition. We used the neonatal piglet as a model for the infant to address (1) the metabolic and physiologic changes due to route of feeding and (2) the adequacy of the amino acid pattern in a pediatric elemental diet.
Diets differed only in their amino acid pattern (modified human milk [MHM] and a commercial pediatric elemental diet [PED]) and were fed continuously for 8 days. Control piglets were fed MHM diet via gastric catheters (IG) and were compared with pigs fed MHM diet via venous catheters (IV) or to pigs IG-fed PED.
MHM-IV piglets experienced enlarged livers and gut atrophy, and lower nitrogen retention and body protein content. Higher glutamine (and lower glutamate) in PED-IG, compared with MHM-IG, produced no apparent advantage with respect to gut growth or histology. Proline, histidine, and lysine may have been limiting, and isoleucine and valine excessive, in the PED-IG diet as indicated by plasma concentrations, compared with sow-fed piglets; however, imbalances in the amino acid profile were not excessive because nitrogen retention was not different between MHM-IG or PED-IG pigs.
Therefore, the amino acid profile of MHM needs to be modified to improve nitrogen retention during parenteral feeding and the profile of oral PED could be improved to normalize plasma amino acid concentrations.
婴儿的氨基酸需求情况与成人不同,需要确定;对于接受全胃肠外营养的婴儿,其氨基酸需求情况也有所不同。我们使用新生仔猪作为婴儿模型,以探讨(1)喂养途径导致的代谢和生理变化,以及(2)儿科要素饮食中氨基酸模式的充足性。
饮食仅在氨基酸模式上有所不同(改良人乳[MHM]和一种市售儿科要素饮食[PED]),持续喂养8天。对照仔猪通过胃导管饲喂MHM饮食(经胃喂养[IG]),并与通过静脉导管饲喂MHM饮食的仔猪(经静脉喂养[IV])或经胃喂养PED的仔猪进行比较。
经静脉喂养MHM的仔猪出现肝脏肿大和肠道萎缩,氮保留和身体蛋白质含量较低。与经胃喂养MHM相比,经胃喂养PED中较高的谷氨酰胺(和较低的谷氨酸)在肠道生长或组织学方面未产生明显优势。与母猪喂养的仔猪相比,血浆浓度表明,经胃喂养PED的饮食中脯氨酸、组氨酸和赖氨酸可能是限制性的,而异亮氨酸和缬氨酸过量;然而,氨基酸谱的失衡并不严重,因为经胃喂养MHM或经胃喂养PED的仔猪之间的氮保留没有差异。
因此,需要修改MHM的氨基酸谱,以改善胃肠外喂养期间的氮保留,并且可以改进口服PED的氨基酸谱,以使血浆氨基酸浓度正常化。