Bowen Raffick A R, Clandinin Michael T
Nutrition and Metabolism Research Group, Department of Agricultural, Food and Nutritional Science, Uniersity of Alberta, Edmonton, Canada.
Br J Nutr. 2005 May;93(5):601-11. doi: 10.1079/bjn20041390.
One of the debates in infant nutrition concerns whether dietary 18 : 3n-3 (linolenic acid) can provide for the accretion of 22 : 6n-3 (docosahexaenoic acid, DHA) in neonatal tissues. The objective of the present study was to determine whether low or high 18 : 3n-3 v. preformed 22 : 6n-3 in the maternal diet enabled a similar 22 : 6n-3 content in the phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylserine (PS) of glial cells from whole brain (cerebrum and cerebellum) of 2-week-old rat pups. At parturition, the dams were fed semi-purified diets containing either increasing amounts of 18 : 3n-3 (18 : 2n-6 to 18 : 3n-3 fatty acid ratio of 7.8 : 1, 4.4 : 1 or 1 : 1), preformed DHA, or preformed 20 : 4n-6 (arachidonic acid)+DHA. During the first 2 weeks of life, the rat pups from the respective dams received only their dam's milk. The fatty acid composition of the pups' stomach contents (dam's milk) and phospholipids from glial cells were quantified. The 20 : 4n-6 and 22 : 6n-3 content in the stomach from rat pups at 2 weeks of age reflected the fatty acid composition of the dam's diet. The 20 : 4n-6 content of PE and PS in the glial cells was unaffected by maternal diet treatments. Preformed 22 : 6n-3 in the maternal diet increased the 22 : 6n-3 content of glial cell PE and PS compared with maternal diets providing an 18 : 2n-6 to 18 : 3 n-3 fatty acid ratio of 7.8 : 1, 4.4 : 1 or 1 : 1 (P<0.0001). There was no significant difference in the 20 : 4n-6 and 22 : 6n-3 content of glial cell PC and PI among maternal diet treatments. It was concluded that maternal dietary 22 : 6n-3 is more effective than low or high levels of maternal dietary 18 : 3n-3 at increasing the 22 : 6n-3 content in PE and PS of glial cells from the whole brain of rat pups at 2 weeks of age. The findings from the present study have important implications for human infants fed infant formulas that are devoid of 22 : 6n-3.
婴儿营养领域的争论之一是，膳食中的18:3n-3（亚麻酸）能否满足新生儿组织中22:6n-3（二十二碳六烯酸，DHA）的累积需求。本研究的目的是确定母体饮食中低水平或高水平的18:3n-3与预先形成的22:6n-3相比，是否能使2周龄幼鼠全脑（大脑和小脑）神经胶质细胞的磷脂酰胆碱（PC）、磷脂酰乙醇胺（PE）、磷脂酰肌醇（PI）和磷脂酰丝氨酸（PS）中的22:6n-3含量相似。分娩时，给母鼠喂食半纯化日粮，其中分别含有逐渐增加的18:3n-3（18:2n-6与18:3n-3脂肪酸比例为7.8:1、4.4:1或1:1）、预先形成的DHA，或预先形成的20:4n-6（花生四烯酸）+DHA。在出生后的前2周，各母鼠的幼鼠仅食用母乳。对幼鼠胃内容物（母乳）和神经胶质细胞磷脂的脂肪酸组成进行了定量分析。2周龄幼鼠胃中的20:4n-6和22:6n-3含量反映了母鼠饮食的脂肪酸组成。神经胶质细胞中PE和PS的20:4n-6含量不受母体饮食处理的影响。与提供18:2n-6与18:3n-3脂肪酸比例为7.8:1、4.4:1或1:1的母体饮食相比，母体饮食中预先形成的22:6n-3增加了神经胶质细胞PE和PS中的22:6n-3含量（P<0.0001）。母体饮食处理之间，神经胶质细胞PC和PI中的20:4n-6和22:6n-3含量没有显著差异。研究得出结论，在增加2周龄幼鼠全脑神经胶质细胞PE和PS中22:6n-3含量方面，母体饮食中的22:6n-3比低水平或高水平的母体饮食18:3n-3更有效。本研究结果对于食用不含22:6n-3婴儿配方奶粉的人类婴儿具有重要意义。
