单胃动物小肠内可消化性碳水化合物的吸收及其调控

本文阐述单胃动物小肠内可消化性碳水化合物的吸收及其调控机制。可消化性碳水化合物在单胃动物体内的降解产物主要为葡萄糖、果糖、半乳糖和双糖。葡萄糖、果糖和半乳糖在小肠内,由小肠内绒毛上皮细胞或细胞间隙直接吸收;双糖在双糖酶的作用下水解成单糖形式,为小肠绒毛上皮细胞吸收。其吸收机制可分为3个途径:主动吸收、被动吸收以及通过细胞间隙直接吸收。其中主动吸收是主要的吸收途径。调控小肠可消化性碳水化合物吸收的因素较多,包括吸收面积、Na 电化学梯度、细胞膜脂质成分、转运细胞与非转运细胞比例、转运子周转速率、亲和系数等因素。通过多种因子的调控作用,能有效地促进碳水化合物的吸收,以满足动物体的生长和发育的需要。

Absorption and regulation of digestible carbohydrate in small intestine of monogastric animal

The mechanisms of absorption and regulation of digestible carbohydrate in small intestine of monogastricanimal were reviewed in the article.The main end productions of digestible carbohydrate were glucose,fructose,galactoseand disaccharides in monogastric animal.Glucose,fructose and galactose were directly absorbed by enterocytes in small in-testine or para cellular permeability;disaccharides were broken down into monosaccharides with the help of disaccharidesand were absorbed by enterocytes.The absorption embraced three pathways:active absorption,passive absorption and paracellular permeability.Among them,active absorption was the major pathway.There were many factors to contribute to theregulation,such as the changes of absorption areas,electrochemical gradient of Na ,the rate of transport cell to non- trans-port cell,turnovers of transporters and so on.With the regulation of these factors,animal could absorb carbohydrate effec-tively to meet the growth and development requirement.