Long-chain n-3 fatty acids enhance neonatal insulin-regulated protein metabolism in piglets by differentially altering muscle lipid composition.
This study investigated the role of long-chain n-3 polyunsaturated fatty acids (LCn-3PUFAs) of muscle phospholipids in the regulation of neonatal metabolism. Twenty-eight piglets were weaned at 2 days of age and raised on one of two milk formulas that consisted of either a control formula supplying 0% or a formula containing 3.5% LCn-3PUFAs until 10 or 28 days of age. There was a developmental decline in the insulin sensitivity of amino acid disposal in control pigs during the first month of life, with a slope of -2.24 micromol.kg(-1).h(-1) (P = 0.01) per unit of insulin increment, as assessed using hyperinsulinemic-euglycemic-euaminoacidemic clamps. LCn-3PUFA feeding blunted this developmental decline, resulting in differing insulin sensitivities (P < 0.001). When protein metabolism was assessed under parenteral feeding-induced hyperinsulinemia, LCn-3PUFAs reduced by 16% whole body oxidative losses of amino acids (from 238 to 231 micromol.kg(-1).h(-1); P = 0.06), allowing 41% more amino acids to accrete into body proteins (from 90 to 127 micromol.kg(-1).h(-1); P = 0.06). The fractional synthetic rate of muscle mixed proteins remained unaltered by the LCn-3PUFA feeding. However, LCn-3PUFAs retarded a developmental increase in the essential-to-nonessential amino acid ratio of the muscle intracellular free pool (P = 0.05). Overall, alterations in metabolism were concomitant with a preferential incorporation of LCn-3PUFAs into muscle total membrane phospholipids (P < 0.001), in contrast to intramuscular triglycerides. These results underscore the potential role of LCn-3PUFAs as regulators of different aspects of protein metabolism in the neonate.
Bergeron
Karen
K
Department of Animal Science, Faculty of Food Sciences and Agriculture, Laval University Québec, Québec, Canada.
Julien
Pierre
P
Davis
Teresa A
TA
Myre
Alexandre
A
Thivierge
M Carole
MC
D000597:Amino Acids, Branched-Chain / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001786:Blood Glucose / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D007328:Insulin / Q000502:physiology*; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D010289:Parenteral Nutrition, Total; D010649:Phenylalanine / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D034421:Sus scrofa
D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D007328:Insulin; D008563:Membrane Lipids; D011506:Proteins; D010649:Phenylalanine