Keelan M, Clandinin M T, Thomson A B
Department of Medicine, University of Alberta, Edmonton, Canada.
Lipids. 1997 Aug;32(8):895-901. doi: 10.1007/s11745-997-0115-z.
Refeeding a diet initially given shortly after weaning results in a different adaptive change in the in vitro intestinal uptake of sugars and lipids than if the diet is given for the first time at a later age. This study was undertaken in rats to test the hypothesis that changes in nutrient uptake associated with refeeding diets containing beef tallow (S), beef tallow plus 1% cholesterol (Sc), fish oil (F), or fish oil plus cholesterol (Fc) are associated with changes in the brush border membrane (BBM) phospholipids and phospholipid fatty acids. Weanling Sprague-Dawley rats were fed ad libitum one of the four diets. At 35 d of age (about 2 wk after weaning), the rats were maintained on either the same diet used at weaning, or were switched to one of the other semisynthetic diets which were then fed for a further 7 wk. At week nine (2 + 7) the rats were either continued on the same diet or were switched back to the original diet for 2 wk (2 + 7 + 2). The groups of animals which were compared included SSSc vs. ScSSc; ScScS vs. SScS; FFFc vs. FcFFc; and FcFcF vs. FFcF. Refeeding S, Sc, F, or Fc had no effect on food consumption or on body weight gain. Refeeding Fc resulted in increased ileal BBM total phospholipids, whereas rechallenge with F resulted in a decline in the jejunal BBM ratio of phospho-lipid/cholesterol. Refeeding Sc resulted in a decrease in the ileal BBM phosphatidylcholine (PC). In rats rechallenged with Fc, there was increased ileal BBM sphingomyelin (SM), increased ileal BBM phosphatidylethanolamine (PE), decreased ileal BBM PC/PE, and an increased ileal BBM SM/PC. Refeeding had no effect on the fatty acyl constituents of the jejunal of ileal BBM PC or PE. These results suggest that there are late effects of the early introduction of dietary cholesterol on intestinal BBM phospholipid content and composition that may contribute to the previously reported changes in intestinal nutrient absorption.
断奶后不久即开始喂食某种日粮，与在较晚年龄首次喂食该日粮相比，会导致体外肠道对糖类和脂质的摄取出现不同的适应性变化。本研究以大鼠为对象，旨在检验以下假设：重新喂食含牛脂（S）、牛脂加1%胆固醇（Sc）、鱼油（F）或鱼油加胆固醇（Fc）的日粮所引起的营养物质摄取变化，与刷状缘膜（BBM）磷脂及磷脂脂肪酸的变化有关。将断乳的斯普拉格-道利大鼠随意喂食四种日粮中的一种。在35日龄（约断奶后2周）时，大鼠继续食用断奶时所喂的同一种日粮，或转喂其他半合成日粮之一，并再喂7周。在第9周（2 + 7）时，大鼠要么继续食用同一种日粮，要么换回原来的日粮，再喂2周（2 + 7 + 2）。所比较的动物组包括SSSc与ScSSc；ScScS与SScS；FFFc与FcFFc；以及FcFcF与FFcF。重新喂食S、ScF或Fc对食物消耗或体重增加均无影响。重新喂食Fc导致回肠BBM总磷脂增加，而再次喂食F则导致空肠BBM磷脂/胆固醇比值下降。重新喂食Sc导致回肠BBM磷脂酰胆碱（PC）减少。在再次喂食Fc的大鼠中，回肠BBM鞘磷脂（SM）增加，回肠BBM磷脂酰乙醇胺（PE）增加，回肠BBM PC/PE降低，回肠BBM SM/PC增加。重新喂食对空肠或回肠BBM PC或PE的脂肪酰成分没有影响。这些结果表明，早期引入膳食胆固醇对肠道BBM磷脂含量和组成有后期影响，这可能是先前报道的肠道营养吸收变化的原因。
