Anabolic Signaling and Protein Deposition Are Enhanced by Intermittent as Compared 1 with Continuous Feeding in Skeletal Muscle of Neonates 2 Running title : Intermittent feeding increases muscle protein

20 Orogastric tube feeding is indicated for neonates with impaired ability to ingest, and can 21 be administered by intermittent bolus or continuous schedule. Our aim was to determine 22 whether feeding modalities affect muscle protein deposition and to identify mechanisms 23 involved. Neonatal pigs were overnight fasted (FAS) or fed the same amount of food 24 continuously (CON) or intermittently (INT; 7 x 4 h meals) for 29 h. For 8 h, between hour 20 25 and 28, pigs were infused with [H5]phenylalanine and [H2]tyrosine and amino acid (AA) net 26 balances were measured across the hindquarters. Insulin, branched-chain AA, phenylalanine and 27 tyrosine arterial concentrations, and whole-body phenylalanine and tyrosine fluxes were greater 28 for INT after the meal than for CON or FAS. The activation of signaling proteins leading to 29 initiation of mRNA translation including eukaryotic initiation factor (eIF) 4E•eIF4G complex 30 formation in muscle was enhanced by INT compared to CON feeding or FAS. Signaling 31 proteins of protein degradation were not affected by feeding modalities except for microtubule32 associated protein light chain 3-II (LC3-II) which was highest in the FAS. Across the 33 hindquarters, AA net removal increased for INT but not for CON or FAS, with protein 34 deposition greater for INT. This was because protein synthesis increased following feeding for 35 INT but remained unchanged for CON and FAS, while there was no change in protein 36 degradation across any dietary treatment. These results suggest that muscle protein accretion in 37 neonates is enhanced with intermittent bolus to a greater extent than continuous feeding, mainly 38 by increased protein synthesis. 39