El-Kadi Samer W, Boutry-Regard Claire, Suryawan Agus, Nguyen Hanh V, Kimball Scot R, Fiorotto Marta L, Davis Teresa A
United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA.
Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA, USA.
Curr Dev Nutr. 2020 Nov 24;4(12):nzaa170. doi: 10.1093/cdn/nzaa170. eCollection 2020 Dec.
Orogastric tube feeding is frequently prescribed for neonates who cannot ingest food normally. In a piglet model of the neonate, greater skeletal muscle growth is sustained by upregulation of translation initiation signaling when nutrition is delivered by intermittent bolus meals, rather than continuously.
The objective of this study was to determine the long-term effects of feeding frequency on organ growth and the mechanism by which feeding frequency modulates protein anabolism in these organs.
Eighteen neonatal pigs were fed by gastrostomy tube the same amount of a sow milk replacer either by continuous infusion (CON) or on an intermittent bolus schedule (INT). After 21 d of feeding, the pigs were killed without interruption of feeding (CON; = 6) or immediately before (INT-0; = 6) or 60 min after (INT-60; = 6) a meal, and fractional protein synthesis rates and activation indexes of signaling pathways that regulate translation initiation were measured in the heart, jejunum, ileum, kidneys, and liver.
Compared with continuous feeding, intermittent feeding stimulated the growth of the liver (+64%), jejunum (+48%), ileum (+40%), heart (+64%), and kidney (+56%). The increases in heart, kidney, jejunum, and ileum masses were proportional to whole body lean weight gain, but liver weight gain was greater in the INT-60 than the CON, and intermediate for the INT-0 group. For the liver and ileum, but not the heart, kidney, and jejunum, INT-60 compared with CON pigs had greater fractional protein synthesis rates (22% and 48%, respectively) and was accompanied by an increase in ribosomal protein S6 kinase 1 and eukaryotic initiation factor 4E binding protein 1 phosphorylation.
These results suggest that intermittent bolus compared with continuous orogastric feeding enhances organ growth and that in the ileum and liver, intermittent feeding enhances protein synthesis by stimulating translation initiation.
对于无法正常摄入食物的新生儿，常采用经口胃管喂养。在新生仔猪模型中，当通过间歇性推注喂养而非持续喂养提供营养时，翻译起始信号的上调可维持更大的骨骼肌生长。
本研究的目的是确定喂养频率对器官生长的长期影响以及喂养频率调节这些器官中蛋白质合成代谢的机制。
18只新生仔猪通过胃造口管以连续输注（CON）或间歇性推注方案（INT）给予等量的母猪代乳品。喂养21天后，在不中断喂养的情况下处死仔猪（CON组；n = 6），或在进食前（INT-0组；n = 6）或进食后60分钟（INT-60组；n = 6）立即处死，测量心脏、空肠、回肠、肾脏和肝脏中蛋白质合成率分数以及调节翻译起始的信号通路的激活指数。
与持续喂养相比，间歇性喂养促进了肝脏（+64%）、空肠（+48%）、回肠（+40%）、心脏（+64%）和肾脏（+56%）的生长。心脏、肾脏、空肠和回肠重量的增加与全身瘦体重增加成比例，但INT-60组的肝脏重量增加大于CON组，INT-0组处于中间水平。对于肝脏和回肠，而非心脏、肾脏和空肠，与CON组仔猪相比，INT-60组的蛋白质合成率分数更高（分别为22%和48%），并伴有核糖体蛋白S6激酶1和真核起始因子4E结合蛋白1磷酸化增加。
这些结果表明，与持续经口胃管喂养相比，间歇性推注喂养可促进器官生长，并且在回肠和肝脏中，间歇性喂养通过刺激翻译起始来增强蛋白质合成。
