Location: Children's Nutrition Research CenterTitle: Skeletal muscle protein synthesis in neonatal pigs is increased more by intermittent bolus than continuous feeding Author
Submitted to: Pediatric Academic Society
Publication Type: Abstract Only
Publication Acceptance Date: 4/19/2011
Publication Date: 4/30/2011
Citation: Gazzaneo, M.C., Suryawan, A., Orellana, R.A., Murgas-Torrazza, R., Srivastava, N., El-Kadi, S.W., Nguyen, H.V., Almonaci, R., Wilson, F.A., Fiorotto, M.L., Davis, T.A. 2011. Skeletal muscle protein synthesis in neonatal pigs is increased more by intermittent bolus than continuous feeding [abstract]. In: Proceedings of the 2011 Annual Conference of the Pediatric Academic Society and the Asian Society for Pediatric Research. Session: Patient oriented neonatal nutritional clinical research, April 30-May 3, 2011, Denver, Colorado. 2855.5. Interpretive Summary:
Technical Abstract: Feeding by orogastric tube, using either continuous or intermittent bolus delivery, is common for infants for whom normal feeding is contraindicated. To determine the impact of different feeding modalities on muscle protein anabolism, neonatal pigs (5-7 day old) received a balanced enteral formula either by intermittent bolus (B, n=13) every four hours or were continuously fed (C, n=9). Fractional protein synthesis rates and translational control mechanisms in skeletal muscle were examined at 0, 24 and 25.5 hours. Plasma amino acid and insulin levels were modestly increased in the continuously fed group and mimicked the pulsatile pattern of meal feeding in the bolus group. Feeding increased protein synthesis by 60 percent in the continuous group, by 63 percent in the bolus group before a meal, and by 121 percent after a bolus feed. The activation of protein kinase B (PKB), proline-rich Akt substrate of 40 kDa (PRAS 40), mammalian target of rapamycin (mTOR), eukaryotic initiation factor (eIF) 4E binding protein (4EBP1), formation of the active eIF4E-eIF4G complex and rp S6 kinase 1 (S6K1) were unaffected by continuous feeding but were increased more than 10 fold after a bolus meal. In neonatal pigs fed continuously and in those intermittent bolus fed, there was no change in the phosphorylation of insulin receptor substrate 1(Ser/Thr) (IRS-1 (Ser/Thr)), adenosine monophosphate kinase (AMPK), elongation factor 2 (eEF-2), and eukaryotic initiation factor alpha (eIF2-alpha). In conclusion, these results suggest that intermittent bolus feeding increases muscle protein synthesis to a greater extent than continuous feeding by stimulating translation initiation.