大黄鱼消化系统胚后发育的组织学研究

应用显微技术对大黄鱼Pseudosciaena crocea消化系统胚后发育的形态和组织结构进行了研究。鱼苗孵化出膜至22日龄时每天取样1次,22至30日龄时每两天取样1次,30日龄以后每5天取样1次,直到60日龄。结果表明：在水温为25.6-29.4℃条件下,2日龄仔鱼肝脏出现,肛孔开裂;3日龄仔鱼胰脏、幽门盲囊出现,口形成;4日龄仔鱼胆囊出现,食道黏膜上皮中出现较多黏液细胞,胃肠分化,肠后端具肠瓣与直肠分界,胃肠蠕动,口和肛门与外界相通;5日龄仔鱼肝脏分化为两叶,胰脏分散分布在肠的周围;12-13日龄仔鱼胃分化为贲门部、幽门部和胃盲囊三部分,肠壁褶皱形成;36日龄稚鱼胃腺发育较好,幽门盲囊结构与成鱼相似,共16条。随着仔、稚、幼鱼的个体发育,消化道进一步扩张,肌肉层加厚,黏膜层皱褶加深,黏液腺增多。60日龄幼鱼,消化道和消化腺发育较完善,基本具备了成鱼消化系统的组织结构。文中还讨论了大黄鱼育苗过程中的3个＂危险期＂与消化系统发育变态的关系。

Post-embryonic histological development in digestive system of large yellow croaker Pseudosciaena crocea

The morphology and histology were described in post-embryonic development of digestive system of large yellow croaker Pseudosciaena crocea everyday from the 1st to 22th day after hatching（DAH）,every other day from the 22th to 30th DAH,and every 5 days from the 30th to 60th DAH under light microscopy.The results showed that the liver organ appeared,and the anus was opened on the 2nd DAH at water temperature from 25.6 to 29.4 ℃.The pancreas,pyloric caeca and mouth were formed on the 3rd DAH.The mouth and anus opened on the 4th DAH,while the gallbladder occurred at the same time.Many mucous cells were present in the mucosal epithelium of the oesophagus.Stomach was different from the intestine in that at the posterior to the intestine,it had lamellas.There was a boundary between the intestine and rectum.The stomach and intestines were peristaltic.On the 5th DAH,the liver of the larvae were divided into 2 parts.Pancreatic tissue was present in areas surrounding the intestine;from the 12th to 13th DAH,the stomach were composed of 3 parts：cardiac,pyloric and caecum gastricum.The intestine walls seemed rugose.The stomach gland developed completely on the 36th DAH.There were 16 pyloric caecae,similar to the caecae in the adult.At hatching,the larvae had an enlarging digestive tract,thicker muscles,pronounced folding mucosa,and many mucous glands.On the 60th DAH,the digestive tract and gland were well developed,indicating the acquisition of an adult digestion mode.The three ＂critical changes＂ in ontogenetic morphology of digestive system in the cultured large yellow croaker were discussed as well.