Comparison of the activities of digestive enzymes in the intestinal brush border membrane between the mudskipper Boleophthalmus pectinirostris and Chinese black sleeper Bostrichthys sinensis
采用酶学分析的方法,研究了大弹涂鱼和中华乌塘鳢肠刷状缘膜的麦芽糖酶、蔗糖酶、乳糖酶、海藻糖酶、纤维二糖酶、碱性磷酸酶、氨基肽酶和γ-谷氨酰转肽酶等8种消化酶的活性。结果表明:1)大弹涂鱼肠Ⅱ刷状缘膜的麦芽糖酶、蔗糖酶、乳糖酶、海藻糖酶和纤维二糖酶等5种二糖酶的比活力均显著高于肠Ⅰ和肠Ⅲ(P<0·05);中华乌塘鳢肠Ⅰ刷状缘膜除乳糖酶外,其余4种二糖酶的比活力均显著高于肠Ⅱ和肠Ⅲ(P<0·05);大弹涂鱼肠Ⅲ碱性磷酸酶、氨基肽酶和γ-谷氨酰转肽酶等3种消化酶的比活力均显著高于肠Ⅰ和肠Ⅱ(P<0·05);中华乌塘鳢肠Ⅱ的这3种消化酶的比活力均显著高于肠Ⅰ和肠Ⅲ(P<0·05);2)大弹涂鱼各段肠刷状缘膜的5种二糖酶的比活力均显著高于中华乌塘鳢(P<0·05),前者肠刷状缘膜碱性磷酸酶、氨基肽酶和γ-谷氨酰转肽酶等3种消化酶的比活力整体上也稍微高于后者。由此说明:8种消化酶的活性在大弹涂鱼和中华乌塘鳢肠刷状缘膜中的分布模式明显不同,大弹涂鱼和中华乌塘鳢对二糖的消化和吸收的主要部位分别是在肠Ⅱ和肠Ⅰ,而二者对蛋白质、脂类和无机盐等营养吸收的主要部位分别是在肠Ⅲ和肠Ⅱ;大弹涂鱼和中华乌塘鳢肠刷状缘膜的5种二糖酶的活性与两者的食性关系密切,而碱性磷酸酶、氨基肽酶和γ-谷氨酰转肽酶等3种消化酶的活性与两者的食性并无密切的相关性。The activities of eight digestive enzymes, maltase, sucrase, lactase, trehalase, cellobiase, alkaline phosphatase(ALP), aminopeptidase(AP)and γ-glutamyltranspeptidase(γ-GT)of the intestinal brush border membrane(BBM)of the adult mudskipper Boleophthalmus pectinirostris and Chinese black sleeper Bostrichthys sinensis were investigated by means of enzyme analyses. The results showed that the specific activities of five disaccharidases(maltase, sucrase, lactase, trehalase and cellobiase)of the intestinal BBM of the intestine Ⅱwere significantly higher than(P<0.05)those of both the intestineⅠand intestine Ⅲ in the mudskipper, while the specific activities of these five disaccharidases except lactase of the intestinal BBM of the intestineⅠ were significantly higher than(P<0.05)those of both the intestine Ⅱ and intestine in the Chinese black sleeper. The specific activities of three digestive enzymes(ALP, AP and γ-GT)of the intestinal BBM of the intestine Ⅲ were significantly higher than(P<0.05)those of both the intestineⅠ and intestineⅡ in the mudskipper, while the specific activities of these three digestive enzymes of the intestineⅡwere significantly higher than(P<0.05)those of both the intestineⅠ and intestine Ⅲ in the Chinese black sleeper. The activities of five disaccharidases of the intestinal BBM of each intestinal section in the mudskipper were significantly higher than(P<0.05)those in the Chinese black sleeper. Generally, the specific activities of three digestive enzymes(ALP, AP and γ-GT)of the intestinal BBM of the mudskipper were also slightly higher than those of the Chinese black sleeper. In conclusion, the distribution patterns of eight digestive enzymes of the intestinal BBM are different between the mudskipper and Chinese black sleeper. The major regions for disaccharide digestion and absorption in the mudskipper and Chinese black sleeper are intestineⅡ and intestineⅠ, respectively. And, the major regions for nutrient absorption, such as protein, lipid and inorganic salts and etc., in the mudskipper and Chinese black sleeper are intestine Ⅲ and intestineⅡ, respectively. The activities of five disaccharidases of the intestinal BBM in both the mudskipper and Chinese black sleeper are well correlated with their feeding habits. However, the lack of a clear-cut correlation between the activities of three digestive enzymes(ALP, AP and γ-GT)and diets was found in the present study.国家自然科学基金资助项目(No·40476056);; 福建省重大科技项目(2003No26);; 福建省科技重大专项(2004SZ01-02)共同资助~
