Long-chain n-3 fatty acids enhance neonatal insulin-regulated protein metabolism in piglets by differentially altering muscle lipid composition

J Lipid Res. 2007 Nov;48(11):2396-410. doi: 10.1194/jlr.M700166-JLR200. Epub 2007 Aug 2.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids, Branched-Chain / metabolism
  • Animals
  • Animals, Newborn
  • Blood Glucose / metabolism
  • Fatty Acids / metabolism
  • Fatty Acids, Unsaturated / pharmacology*
  • Insulin / physiology*
  • Male
  • Membrane Lipids / metabolism*
  • Muscle, Skeletal / metabolism*
  • Parenteral Nutrition, Total
  • Phenylalanine / metabolism
  • Proteins / metabolism*
  • Sus scrofa


  • Amino Acids, Branched-Chain
  • Blood Glucose
  • Fatty Acids
  • Fatty Acids, Unsaturated
  • Insulin
  • Membrane Lipids
  • Proteins
  • Phenylalanine