摘要
采用酶学分析的方法,研究了大弹涂鱼前期仔鱼、后期仔鱼、稚鱼和早期幼鱼发育过程中胰腺酶、肠酶和胃蛋白酶活性的变化。结果表明,(1)4种胰腺酶(淀粉酶、胰蛋白酶、糜蛋白酶和羧肽酶A)和8种肠酶(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)的比活力均在仔鱼期较高,稚鱼期降至最低,早期幼鱼则急剧上升,而每尾鱼酶的总活力却随着幼体的发育而逐渐增加;(2)胃蛋白酶活性在后期仔鱼才开始检测到,此后一直呈显著上升趋势;(3)早期幼鱼肠部位的4种胰腺酶活性分别占其酶总活性的百分比均显著高于稚鱼期;(4)稚鱼期仅3种肠酶(麦芽糖酶、纤维二糖酶和γ-谷氨酰转肽酶)高度富积在肠刷状缘膜上,而早期幼鱼除蔗糖酶外的7种肠酶在肠刷状缘膜上的富集系数均大于5.1。由此得出结论,(1)在仔鱼期,蛋白质的消化是依靠胰腺酶进行的,进入稚鱼期,胃蛋白酶开始对蛋白质的消化起重要作用;(2)在早期幼鱼,胰腺分泌机制及肠细胞已完全成熟,标志着成鱼的消化模式的形成。
The mudsldpper Boleophthalmus pectinirostris is a commercially important fish in China. At present, this species is widely farmed in the southeastern coastal waters of China. Studies have been focused on early development and larval rearing. Early larval feeding habits have been documented. However, little is known about the digestive enzymes at the early stage of Boleophthalmus pectinirostris. The purpose of this study was to investigate the digestive enzyme activities of this species in order to know its nutritional requirements and establish the feeding protocols for optimizing larval mass rearing production. Changes of pancreatic, intestinal enzymes and pepsin activities in prelarva, postlarva, juvenile and early young fish of Boleophthalmus pectinirostris were investigated by means of enzyme analyses. In order to obtain pancreatic segment （PS） and intestinal segment （IS）, juvenile and early young fish were cut into four parts： head, PS, IS and tail. The intestinal segments were homogenized to purify intestinal brush border membranes （BBM）. The secretion levels of pancreatic enzymes were expressed as percentages of the segmental activity in the IS related to total activity （PS ＋ IS）. The establishment of an efficient intestinal BBM digestion represents the adult mode of digestion by enterocytes. And the degree of purified intestinal BBM was estimated by the enrichment factors and the activities of the intestinal enzymes. The results of this study show that the specific activities of four pancreatic enzymes （amylase, trypsin, chain and carhoxypeptidaseA） and eight intestinal enzymes （maltase, sucrase, luctase, trehalase, cellobiase, alkaline phosphatase, aminopeptidase and γ-glutamyltranspeptidase） are higher in the larval stage, decrease to the lowest levels in the juvenile stage, and increase rapidly in the early young stage. However, the total enzyme activities of individual increase with the development of larvae. Pepsin is initially detected in the postlarval stage, and then it continuously increases rapidly. The percentages of four pancreatic enzymes activities accounting for the total activities are significantly higher in the early young fish than in the juvenile in the intestinal segment.Only three enzymes（maltase,cellobiase and γ-glutamyltranspeptidase）are highly enriched in the intestinal brush border membranes in the juvenile,However,enrichment factors of seven intestinal enzymes in intestinal brush border membranes of the early young fish are all above 5.1 except for sucrase,In conclusion,in the larval stage,protein digestion depends on pancreatic enzymes;and when the larvae develope into the juvenile stage,pepsin plays an important role in protein digestion.The complete achievement of the secretion mechanisms of pancreas and maturation of enterocytes in the early young fish indicate the formation of an adult fish mode of digestion.
出处
《水产学报》
CAS
CSCD
北大核心
2006年第6期733-739,共7页
Journal of Fisheries of China
基金
国家自然科学基金资助项目(40476056)
福建省重大科技项目(2003No.26)
福建省科技重大专项(2004SZ01-02)
关键词
大弹涂鱼
仔鱼
稚鱼
早期幼鱼
胃蛋白酶
胰腺酶
肠酶
肠刷状缘膜
Boleophthalmus pectinirostris
larva
juvenile
young fish
pepsing
pancreatic enzyne
intestinal enzyme
intestinal brush border membrane
