Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/20/2005
Publication Date: 4/2/2005
Citation: Frank, J.W., Escobar, J., Suryawan, A., Nguyen, H.V., Liu, C.W., Kimball, S.R., Jefferson, L.S., Davis, T.A. 2005. Dietary protein and lactose increase protein synthesis via modulation of insulin signaling proteins and translation initiation factors in neonatal pigs [abstract]. The Federation of American Societies for Experimental Biology Conference. Part II (abstract 571.4):A977.
Interpretive Summary: Not Required for an Abstract.
Technical Abstract: Protein synthesis (PS) and eukaryotic initiation factor (eIF) activation are increased in muscle and liver of pigs parenterally infused with insulin and amino acids. This study was arranged as a 3 x 2 factorial with three dietary protein (5, 15, and 25 g•kg BW[-1]•d[-1]) and two lactose levels (low = 11 and high = 23 g•kg BW[-1]•d[-1]). Pigs (N = 42; BW = 1.7 kg) were enterally fed the isocaloric milk diets from 1 to 7 d of age. On d 7, pigs were gavage fed after a 4 h fast and blood samples were collected every 30 min for 1.5 h. Pigs were then euthanized and tissues harvested. Growth and PS in muscle and liver increased with dietary protein and plateaued at the 15 g•kg BW[-1]•d[-1] level (P < 0.001). Growth tended to increase in high lactose fed pigs (P < 0.08). Plasma insulin was greater in the high lactose fed pigs (P < 0.01) and lowest in pigs fed 5 g•kg BW[-1]•d[-1] protein (P < 0.01). Plasma branched-chain amino acids increased as protein intake increased (P < 0.001). Liver and muscle PKB/Akt phosphorylation was greater in the high lactose fed pigs (P < 0.05). Liver and muscle ribosomal S6K1 and 4E-BP1 phosphorylation increased with protein intake and plateaued at the 15 g•kg BW[-1]•d[-1] level (P < 0.01). The results show that growth and PS in neonatal pigs are influenced by dietary protein intake. These changes in growth and PS are associated with activation of eIFs and may be mediated by plasma insulin and amino acid levels.