【作者】 常青；

【导师】 张秀梅；

【作者基本信息】 中国海洋大学 ， 捕捞学， 2006， 博士

【摘要】 半滑舌鳎(Cynoglossus semilaevis )属鲽形目(Pleuronectiformes)、舌鳎科(Cynoglossidae)、舌鳎属(Cynoglossus Buchanan-Hamiltou),为我国近海底层的大型名贵经济鱼类。生长速度快,肉味鲜美,深受广大消费者的喜爱,有着广阔的发展前景。但是在苗种生产过程中,从生物饵料转为配合饵料期间,仍会出现大量的死亡,转饵问题成为限制其扩大再生产的一个关键问题,微颗粒饲料的研制仍是难点所在。为了促进半滑舌鳎养殖的产业化进程,本文开展了半滑舌鳎仔稚鱼营养生理和开口饲料的开发研究,旨在为了解半滑舌鳎不同发育阶段的营养需求,及其高效开口饲料的研制提供理论依据。现将研究结果总结如下:(1)利用形态学和连续组织切片技术,对出膜后1～30d的半滑舌鳎消化系统胚后发育的组织形态学进行了系统观察和研究。研究表明,试验水温为20.0～22.0℃时,孵化后第3d,仔鱼开口摄食,消化道上皮细胞出现分化,肝脏和胰脏开始出现,鱼体开始由内源性营养转向外源性营养。孵化后第5d,卵黄囊完全被吸收,消化道明显分化成口咽腔、食道、胃、前肠和后肠,仔鱼消化系统具备了摄食和消化外源性食物的能力。此后随着鱼体的生长,粘膜层的褶皱增加,消化道上皮细胞进一步分化,肠道分段、盘旋,消化系统从功能和结构上逐步地完善成熟。开口摄食之后,先后发现在后肠出现嗜曙红颗粒,在前肠出现空泡,表明肠上皮细胞吸收了蛋白质和脂肪。继而糖元在肝脏中不断地储存。在出膜后第23天,出现胃腺,标志着稚鱼期的开始。(2)对半滑舌鳎不同发育阶段主要消化酶(酸性蛋白酶、碱性蛋白酶、淀粉酶、脂肪酶)以及与消化吸收相关的碱性磷酸酶的活性变化进行了测定。结果表明,半滑舌鳎在仔鱼发育早期即可检出酸性蛋白酶和碱性蛋白酶的活力,碱性蛋白酶的2个极低值分别出现在仔鱼开口期和仔稚鱼的转变期,酸性蛋白酶的活性从孵化后23 d左右,胃腺出现时开始明显升高。早期仔鱼体内表现出较强的淀粉酶活性,孵化后12 d其活性急剧下降,并一直保持较低的比活力状态。脂肪酶的活性在半滑舌鳎早期仔鱼体内一直较低,进入稚鱼期后开始缓慢上升。碱性磷酸酶活性在变态结束后出现大幅度的升高,这标志着肠组织结构和肠道消化功能的完善。更多还原

【Abstract】 The tongue sole, Cynoglossus semilaevis is a Chinese inshore species with a great potential for aquaculture. In spite of great commercial interest, there is limited information about the biology, nutritional requirements or techniques for intensive rearing of larvae of this species and weaning is still identified as a bottleneck for sustainable production. The aim of this work is to supply reference for the knowing about nutritional requirements and the manufacture of artificial microdiets through studying digestive physiology in different developmental stages of tongue sole and development of prepared microdiets. The results of this study are summarized as follow.ExperimentⅠ.Histological changes of the digestive system and its associated glands were studied in tongue sole Cynoglossus semilaevis from the first day (first day post-hatch dph) until 30 dph. Specimens for this study were hatched from artificially spawned broodstock and maintained in the indoor cement tanks (20.0~22.0℃). At mouth opening (3 dph), lengthening of the digestive tract, mucosae differentiation and pancreas and liver appearance are the most apparent elements. The yolk is gradually resorbed and disappeared at 5 dph., while the digestive tract was differentiated in five portions: buccal-pharyngeal cavity, esophagus, stomach, anterior and posterior intestine. The larvael digestive system is morphologically ready to process external food at this time. During the following period of independent life the most noticeable events occurring are an increase in mucosal folding, cellular differentiation in the luminal epithelia, gut segmentation and looping. Thus, these digestive tract and associated glands become mature gradually and complete the morphological digestive features characteristic with increasing age and feeding更多还原