Bergeron Karen, Julien Pierre, Davis Teresa A, Myre Alexandre, Thivierge M Carole
Department of Animal Science, Faculty of Food Sciences and Agriculture, Laval University Québec, Québec, Canada.
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.
本研究调查了肌肉磷脂中的长链n-3多不饱和脂肪酸（LCn-3PUFAs）在新生儿代谢调节中的作用。28头仔猪在2日龄时断奶，并采用两种乳配方之一饲养，一种是提供0% LCn-3PUFAs的对照配方，另一种是含3.5% LCn-3PUFAs的配方，直至10日龄或28日龄。在出生后的第一个月，对照仔猪氨基酸处理的胰岛素敏感性呈发育性下降，每单位胰岛素增量的斜率为-2.24 μmol·kg⁻¹·h⁻¹（P = 0.01），这是通过高胰岛素-正常血糖-正常氨基酸钳夹技术评估得出的。喂养LCn-3PUFAs可减弱这种发育性下降，导致胰岛素敏感性出现差异（P < 0.001）。当在肠外喂养诱导的高胰岛素血症状态下评估蛋白质代谢时，LCn-3PUFAs使全身氨基酸氧化损失减少了16%（从238降至231 μmol·kg⁻¹·h⁻¹；P = 0.06），使更多氨基酸（41%）能够积累到身体蛋白质中（从90增至127 μmol·kg⁻¹·h⁻¹；P = 0.06）。LCn-3PUFAs喂养并未改变肌肉混合蛋白的合成率。然而，LCn-3PUFAs延缓了肌肉细胞内游离池中必需氨基酸与非必需氨基酸比例的发育性增加（P = 0.05）。总体而言，代谢变化伴随着LCn-3PUFAs优先掺入肌肉总膜磷脂中（P < 0.001），与肌肉内甘油三酯情况相反。这些结果强调了LCn-3PUFAs作为新生儿蛋白质代谢不同方面调节因子的潜在作用。
