Department of Pediatrics, Division of Neonatology, Erasmus Medical Centre-Sophia Children's Hospital, Rotterdam, Netherlands.
Am J Clin Nutr. 2011 Dec;94(6):1496-503. doi: 10.3945/ajcn.111.024166. Epub 2011 Nov 2.
Infant nutrition has a major impact on child growth and functional development. Low and high intakes of protein or amino acids could have a detrimental effect.
The objective of the study was to determine the lysine requirement of enterally fed term neonates by using the indicator amino acid oxidation (IAAO) method. L-[1-(13)C]phenylalanine was used as an indicator amino acid.
Twenty-one neonates were randomly assigned to lysine intakes that ranged from 15 to 240 mg · kg(-1) · d(-1). Breath, urine, and blood samples were collected at baseline and during the plateau. The mean lysine requirement was determined by using biphasic linear regression crossover analysis on the fraction of (13)CO(2) recovery from L-[1-(13)C]phenylalanine oxidation (F(13)CO(2)) and phenylalanine oxidation rates calculated from the L-[1-(13)C]phenylalanine enrichment of urine and plasma.
The mean (±SD) phenylalanine flux calculated from urine and plasma L-[1-(13)C]phenylalanine enrichment data were 88.3 ± 6.9 and 84.5 ± 7.4 μmol · kg(-1) · h(-1), respectively. Graded intakes of lysine had no effect on phenylalanine fluxes. The mean lysine requirement determined by F(13)CO(2) was 130 mg · kg(-1) · d(-1) (upper and lower CIs: 183.7 and 76.3 mg · kg(-1) · d(-1), respectively). The mean requirement was identical to the requirement determined by using phenylalanine oxidation rates in urine and plasma.
The mean lysine requirement of enterally fed term neonates was determined by using F(13)CO(2) and phenylalanine oxidation rates calculated from the L-[1-(13)C]phenylalanine enrichment of urine and plasma. These methods yielded a similar result of 130 mg lysine · kg(-1) · d(-1). This study demonstrates that sampling of (13)CO(2) in expired air is sufficient to estimate the lysine requirement by using the IAAO method in infants. This trial was registered at www.trialregister.nl as NTR1610.
婴儿营养对儿童生长和功能发育有重大影响。蛋白质或氨基酸的低摄入量或高摄入量可能会产生有害影响。
本研究旨在通过使用示踪氨基酸氧化（IAAO）法确定肠内喂养的足月新生儿的赖氨酸需求量。L-[1-（13）C]苯丙氨酸被用作示踪氨基酸。
21 名新生儿随机分配到赖氨酸摄入量为 15 至 240mg·kg（-1）·d（-1）的范围。在基线和平台期采集呼吸、尿液和血液样本。使用双相线性回归交叉分析，根据 L-[1-（13）C]苯丙氨酸氧化的（13）CO2 恢复分数（F（13）CO2）和从尿液和血浆中 L-[1-（13）C]苯丙氨酸的丰度计算的苯丙氨酸氧化速率，确定平均赖氨酸需求量。
根据尿液和血浆 L-[1-（13）C]苯丙氨酸丰度数据计算出的平均（±SD）苯丙氨酸通量分别为 88.3±6.9 和 84.5±7.4μmol·kg（-1）·h（-1）。赖氨酸的分级摄入量对苯丙氨酸通量没有影响。通过 F（13）CO2 确定的平均赖氨酸需求量为 130mg·kg（-1）·d（-1）（上下置信区间分别为 183.7 和 76.3mg·kg（-1）·d（-1））。平均需求量与通过尿液和血浆中苯丙氨酸氧化速率确定的需求量相同。
通过 F（13）CO2 和从尿液和血浆中 L-[1-（13）C]苯丙氨酸丰度计算的苯丙氨酸氧化速率，使用 IAAO 法确定了肠内喂养的足月新生儿的平均赖氨酸需求量。这些方法得出的结果相似，即 130mg 赖氨酸·kg（-1）·d（-1）。本研究表明，在婴儿中使用 IAAO 法估计赖氨酸需求量时，呼吸空气中（13）CO2 的采样就足够了。该试验在 www.trialregister.nl 上注册为 NTR1610。
