title: Pulsatile delivery of a leucine supplement during long-term continuous enteral feeding enhances lean growth in term neonatal pigs.
abstract: Neonatal pigs are used as a model to study and optimize the clinical treatment of infants who are unable to maintain oral feeding. Using this model, we have shown previously that pulsatile administration of leucine during continuous feeding over 24 h via orogastric tube enhanced protein synthesis in skeletal muscle compared with continuous feeding alone. To determine the long-term effects of leucine pulses, neonatal piglets (n = 11-12/group) were continuously fed formula via orogastric tube for 21 days, with an additional parenteral infusion of either leucine (CON + LEU; 800 μmol·kg-1·h-1) or alanine (CON + ALA) for 1 h every 4 h. The results show that body and muscle weights and lean gain were ∼25% greater, and fat gain was 48% lower in CON + LEU than CON + ALA; weights of other tissues were unaffected by treatment. Fractional protein synthesis rates in longissimus dorsi, gastrocnemius, and soleus muscles were ∼30% higher in CON + LEU compared with CON + ALA and were associated with decreased Deptor abundance and increased mTORC1, mTORC2, 4E-BP1, and S6K1 phosphorylation, SNAT2 abundance, and association of eIF4E with eIF4G and RagC with mTOR. There were no treatment effects on PKB, eIF2α, eEF2, or PRAS40 phosphorylation, Rheb, SLC38A9, v-ATPase, LAMTOR1, LAMTOR2, RagA, RagC, and LAT1 abundance, the proportion of polysomes to nonpolysomes, or the proportion of mRNAs encoding rpS4 or rpS8 associated with polysomes. Our results demonstrate that pulsatile delivery of a leucine supplement during 21 days of continuous enteral feeding enhances lean growth by stimulating the mTORC1-dependent translation initiation pathway, leading to protein synthesis in skeletal muscle of neonates.
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and.
authors.forename: Claire
authors.initials: C
authors.lastname: Boutry
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and.
authors.forename: Samer W
authors.initials: SW
authors.lastname: El-Kadi
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and.
authors.forename: Agus
authors.initials: A
authors.lastname: Suryawan
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and.
authors.forename: Julia
authors.initials: J
authors.lastname: Steinhoff-Wagner
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and.
authors.forename: Barbara
authors.initials: B
authors.lastname: Stoll
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and.
authors.forename: Renán A
authors.initials: RA
authors.lastname: Orellana
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and.
authors.forename: Hanh V
authors.initials: HV
authors.lastname: Nguyen
authors.affiliation: Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.
authors.forename: Scot R
authors.initials: SR
authors.lastname: Kimball
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and.
authors.forename: Marta L
authors.initials: ML
authors.lastname: Fiorotto
authors.affiliation: United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; and tdavis@bcm.edu.
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Davis
mesh_terms: D000409:Alanine / Q000494:pharmacology; D026924:Amino Acid Transport System A / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D064131:Back Muscles; D019587:Dietary Supplements; D004750:Enteral Nutrition; D007263:Infusions, Parenteral; D007930:Leucine / Q000008:administration & dosage / Q000494:pharmacology*; D000076222:Mechanistic Target of Rapamycin Complex 1; D000076225:Mechanistic Target of Rapamycin Complex 2; D046912:Multiprotein Complexes / Q000187:drug effects / Q000378:metabolism; D009124:Muscle Proteins / Q000187:drug effects* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000187:drug effects / Q000378:metabolism; D012269:Ribosomal Proteins / Q000187:drug effects / Q000235:genetics; D034421:Sus scrofa; D013552:Swine; D058570:TOR Serine-Threonine Kinases / Q000187:drug effects / Q000378:metabolism
chemical_list: D026924:Amino Acid Transport System A; D046912:Multiprotein Complexes; D009124:Muscle Proteins; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C031798:ribosomal protein S4; C030254:ribosomal protein S8; D000076222:Mechanistic Target of Rapamycin Complex 1; D000076225:Mechanistic Target of Rapamycin Complex 2; D038744:Ribosomal Protein S6 Kinases, 90-kDa; D058570:TOR Serine-Threonine Kinases; D007930:Leucine; D000409:Alanine
keywords: growth; infant; leucine; orogastric feeding; protein metabolism