Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 6/23/2006
Publication Date: 7/9/2006
Citation: Thivierge, M.C., Bergeron, K., Julien, P., Davis, T.A. 2006. Development and enteral long-chain n-3 fatty acids differentially alters muscle intracellular pools of free amino acids in the neonate piglet [abstract]. Journal of Animal Science. 84(Suppl 1):144. Interpretive Summary:
Technical Abstract: Recent studies suggest that feeding long-chain n-3 fatty acids (LCn-3FA) in the diet may blunt the developmental reduction in insulin sensitivity and anabolism in the neonate piglet. To examine the effect of LCn-3FA on protein anabolism, 2-day-old piglets (n=28) were weaned and assigned to one of two semi-purified milk replacers and raised until 10- or 28-d-old. Milk replacers differed in their fatty acid composition (Control: 0.82%, and Enriched: 10.99% LCn-3FA). At either 10 of 28 d of age, phenylalanine kinetics were conducted by simultaneously infusing L-[1-C(13)]phenylalanine (22 micromol/kg.h) along with total parenteral nutrition (7.9 ml/kg.h). After a 4-h infusion period, piglets were killed and longissimus dorsi muscle was sampled. Fractional synthetic rate of muscle proteins (FSR) was not altered by feeding milk replacer enriched in LCn-3FA. However, FSR decreased between 10 and 28 d of age (from 13 to 8%/d; P<0.01). The age-regulated fall in FSR coincided with reductions in the concentrations of many non-essential amino acids (NEAA) in the cellular milieu (Asp P=0.04; Ala P=0.02; Ser P<0.01; Pro P=0.03). 3-Methyl-histidine, a marker of myofibrillar protein degradation, also decreased (P<0.01) with development. Essential amino acids (EAA) remained mostly unaltered, except Arg (P<0.01) and Phe (P=0.03) concentrations that increased with age. Feeding milk replacer enriched in LCn-3FA reduced the cellular EAA to NEAA ratio (P=0.03). The results suggest that feeding a diet enriched in LCn-3FA blunts the developmental increase in cellular EAA to NEAA ratio but does not block the fall in muscle protein synthesis.