Krogdahl A
J Nutr. 1985 May;115(5):675-85. doi: 10.1093/jn/115.5.675.
Ingested lipids undergo intestinal emulsification, digestion, micellar solubilization, cell membrane permeation, intracellular esterification and incorporation into lipoproteins before release to the interstitial fluid. Bile salts secretion, essential to both emulsification and micelle formation in the intestine, has been found to be influenced by quantity and quality of dietary lipids and by other emulsifiers. Modifications of dietary lipid contents cause changes in pancreatic lipase content and secretion. Colipase secretion by the pancreas seems dependent on both lipid and protein intakes. Intracellular processes essential for lipid absorption increases in rate as lipid intake increases. Bile salts seem to play important roles as moderators of these processes. The ability to digest lipids is not fully developed in the newly hatched poultry. Addition of bile salts, lipase or phospholipids to chick diets improves the digestibility of animal fats, demonstrating that lipid digestive processes are not fully functional in the very young. Physiological studies support these indications. Lipase concentration in pancreatic tissue and intestinal contents of poultry increases several-fold during the first few weeks after hatch. Similar changes with age have been observed in bile salt secretion. The development in enterocytes of fatty acid-binding protein activity seems to parallel the development in lipase activity and bile salt secretion in poultry.
摄入的脂质在释放到组织液之前，会经历肠道乳化、消化、微胶粒增溶、细胞膜渗透、细胞内酯化以及整合到脂蛋白中。胆汁盐的分泌对肠道中的乳化和微胶粒形成至关重要，已发现其受膳食脂质的数量和质量以及其他乳化剂的影响。膳食脂质含量的改变会导致胰脂肪酶含量和分泌的变化。胰腺分泌的辅脂酶似乎依赖于脂质和蛋白质的摄入量。随着脂质摄入量的增加，脂质吸收所必需的细胞内过程的速率会提高。胆汁盐似乎作为这些过程的调节者发挥着重要作用。新孵化的家禽消化脂质的能力尚未完全发育。在雏鸡日粮中添加胆汁盐、脂肪酶或磷脂可提高动物脂肪的消化率，这表明脂质消化过程在幼雏中并未完全发挥功能。生理学研究支持这些迹象。孵化后最初几周内，家禽胰腺组织和肠道内容物中的脂肪酶浓度会增加数倍。胆汁盐分泌也观察到了随年龄的类似变化。家禽肠细胞中脂肪酸结合蛋白活性的发展似乎与脂肪酶活性和胆汁盐分泌的发展平行。
