title: Viscera and muscle protein synthesis in neonatal pigs is increased more by intermittent bolus than by continuous feeding.
abstract: BACKGROUND
  Continuous and intermittent bolus orogastric feedings are strategies used in infants unable to tolerate normal feeds.
  
  
  METHODS
  To determine the effects of feeding modality on protein synthesis in different tissues, neonatal pigs received a balanced formula by orogastric tube as an intermittent bolus feed every 4 h or as a continuous infusion, or were fasted overnight.
  
  
  RESULTS
  As compared with fasting, protein synthesis in gastrocnemius, masseter, and soleus muscles; left ventricle; liver; pancreas; jejunum; and kidney increased in bolus- and continuously fed pigs, but the greatest increase occurred after a bolus meal. Tuberous sclerosis complex (TSC2), the proline-rich AKT substrate of 40 kDa (PRAS40), eukaryotic initiation factor (eIF) 4E binding protein (4EBP1), and ribosomal protein S6 kinase 1 (S6K1) phosphorylation in all tissues, and the proportion of ribosomal protein S4 in liver polysomes were enhanced 90 min following the bolus meal but not immediately before the meal or during continuous feeding. Eukaryotic elongation factor 2 (eEF2) and eIF2α phosphorylation were unaffected by feeding.
  
  
  CONCLUSIONS
  These results suggest that intermittent bolus feeding increases protein synthesis in muscles of different fiber types and visceral tissues to a greater extent than continuous feeding by stimulating translation initiation.
authors.affiliation: U.S. Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Samer W
authors.initials: SW
authors.lastname: El-Kadi
authors.forename: María C
authors.initials: MC
authors.lastname: Gazzaneo
authors.forename: Agus
authors.initials: A
authors.lastname: Suryawan
authors.forename: Renán A
authors.initials: RA
authors.lastname: Orellana
authors.forename: Roberto Murgas
authors.initials: RM
authors.lastname: Torrazza
authors.forename: Neeraj
authors.initials: N
authors.lastname: Srivastava
authors.forename: Scot R
authors.initials: SR
authors.lastname: Kimball
authors.forename: Hanh V
authors.initials: HV
authors.lastname: Nguyen
authors.forename: Marta L
authors.initials: ML
authors.lastname: Fiorotto
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Davis
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D005248:Feeding Methods; D015151:Immunoblotting; D018482:Muscle, Skeletal / Q000502:physiology*; D014176:Protein Biosynthesis / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D013997:Time Factors; D014781:Viscera / Q000502:physiology*