鳜消化系统器官发生的组织学

Histological Study of the Digestive System Organogenesis for the Mandarin Fish, Siniperca chuatsi

利用形态学观察和连续组织切片技术,对出膜后0—35d的鳜仔稚鱼消化系统胚后发育的组织学特征进行了系统研究。结果表明,试验水温为18.0—20.0℃时,鳜初孵仔鱼消化道仅为一段位于脊索下方、卵黄囊上方的实心细胞索,卵黄囊呈椭圆形,含有油球。孵化后第2天,口和肛门形成,消化道贯通。孵化后第4天,消化道上皮细胞出现分化,肝脏和胰脏出现,仔鱼开始由内源性营养向外源性营养转变。孵化后第5天,仔鱼开口摄食,消化道分化成口咽腔、食道、胃、前肠和后肠。孵化后第9天,卵黄囊完全被吸收。此后随着鱼体的生长,消化系统从结构和功能上逐步发育完善和成熟。孵化后第7天前肠中出现空泡,孵化后第8天仔鱼后肠中发现有嗜曙红颗粒,表明肠上皮细胞吸收了脂肪和蛋白质。在孵化后第13天,出现胃腺,标志着稚鱼期的开始。

The development of the digestive tract and accessory glands in the Mandarin fish （Siniperca chuatsi） larvae from hatching to 35 days after hatch （DAH） was morphologically and histologically examined using light microscopy. Hatched at the temperature varying from 18.0 to 20.0℃, the digestive tract of the newly hatched larva of the mandarin fish was a simple closed tube under the notochord and above the posterior segment of the oval yolk sac containing the oil globule. On 2 DAH, the mouth and the anus were opened, the digestive tract run through. On 4 DAH, the epithelium of the digestive tract was differentiated, the live and pancreas appeared, and fish began to turn endogenous feeding to exogenous feeding. On 5 DAH, the larvae begun to ingest exogenous food, the digestive tract was differentiated into five portions： buccopharyngeal cavity, esophagus, stomach, anterior and posterior intestine. The yolk was gradually absorbed and disappeared on 9 DAH. During the following developmental period of the larvae, the structure and function of the digestive system became mature gradually. Infranuclear vacuoles occurred in the anterior intestine on 7 DAH and esoinophilic granulae occurred in the posterior intestine on 8 DAH, which indicates the start of lipid and protein absorption. Gastric glands were observed on 13 DAH, which indicates the passage through the juvenile period.