Chapman Karen P, Courtney-Martin Glenda, Moore Aideen M, Ball Ronald O, Pencharz Paul B
Research Institute, The Hospital for Sick Children, Toronto, ON, Canada.
Am J Clin Nutr. 2009 Jan;89(1):134-41. doi: 10.3945/ajcn.2008.26654. Epub 2008 Dec 3.
The threonine requirement of human neonates who receive parenteral nutrition (PN) has not been determined experimentally.
The objective was to determine the parenteral threonine requirement for human neonates by using the minimally invasive indicator amino acid oxidation technique with L-[1-(13)C]phenylalanine as the indicator amino acid.
Nine postsurgical neonates were randomly assigned to 16 threonine intakes ranging from 10 to 100 mg . kg(-1) . d(-1). Breath and urine samples were collected at baseline and at plateau for (13)CO(2) and amino acid enrichment, respectively. The mean threonine requirement was determined by applying a 2-phase linear regression crossover analysis to the measured rates of (13)CO(2) release (F(13)CO(2)) and L-[1-(13)C]phenylalanine oxidation.
The mean threonine parenteral requirement determined by using phenylalanine oxidation was 37.6 mg . kg(-1) . d(-1) (upper and lower confidence limits, respectively: 29.9 and 45.2 mg . kg(-1) . d(-1)) and by using F(13)CO(2) oxidation was 32.8 mg . kg(-1) . d(-1) (upper and lower confidence limits, respectively: 29.7 and 35.9 mg . kg(-1) . d(-1)). Graded intakes of threonine had no effect on phenylalanine flux.
This is the first study to report on the threonine requirement for human neonates receiving PN. We found that the threonine requirement for postsurgical PN-fed neonates is 22-32% of the content of threonine that is presently found in commercial PN solutions (111-165 mg . kg(-1) . d(-1)).
接受肠外营养（PN）的人类新生儿的苏氨酸需求量尚未通过实验确定。
采用以L-[1-(13)C]苯丙氨酸为指示氨基酸的微创指示氨基酸氧化技术，确定人类新生儿的肠外苏氨酸需求量。
9名术后新生儿被随机分配至16种苏氨酸摄入量组，摄入量范围为10至100 mg·kg(-1)·d(-1)。分别在基线期和平稳期采集呼气和尿液样本，用于检测(13)CO(2)和氨基酸富集情况。通过对测得的(13)CO(2)释放率（F(13)CO(2)）和L-[1-(13)C]苯丙氨酸氧化率进行两阶段线性回归交叉分析，确定平均苏氨酸需求量。
采用苯丙氨酸氧化法测定的平均肠外苏氨酸需求量为37.6 mg·kg(-1)·d(-1)（置信上限和下限分别为：29.9和45.2 mg·kg(-1)·d(-1)），采用F(13)CO(2)氧化法测定的为32.8 mg·kg(-1)·d(-1)（置信上限和下限分别为：29.7和35.9 mg·kg(-1)·d(-1)）。分级摄入苏氨酸对苯丙氨酸通量无影响。
这是第一项报道接受PN的人类新生儿苏氨酸需求量的研究。我们发现，接受术后PN喂养的新生儿的苏氨酸需求量为目前市售PN溶液中苏氨酸含量（111 - 165 mg·kg(-1)·d(-1)）的22% - 32%。
