尖吻鲈仔鱼骨骼发育观察

目的]掌握尖吻鲈仔鱼期的骨骼生长发育规律,为开展尖吻鲈骨骼发育相关基因研究及鱼类化石探究提供基础资料.方法]采用软骨—硬骨双染染色技术,连续观测0~23日龄尖吻鲈仔鱼发育过程中脊柱及附肢骨骼中的胸鳍、背鳍、腹鳍、尾鳍、臀鳍形成及生长发育特征.结果]1日龄的尖吻鲈全长1.70±0.10 mm,其身体细长笔直,骨骼尚未开始骨化,附肢骨骼未出现;3日龄时,尖吻鲈仔鱼脊索发生自然弯曲并开始发育,胸鳍、尾鳍原基逐渐形成;5日龄时,尖吻鲈仔鱼脊索末端开始向上弯曲,背鳍开始发育;9日龄时,尖吻鲈仔鱼脊索出现弯曲,髓弓和脉弓开始形成,尾杆骨上翘,随之形成尾鳍,胸鳍原基、背鳍鳍皱开始出现,臀鳍开始发育;13日龄时,尖吻鲈仔鱼的胸鳍和尾鳍发育基本完成,髓棘、脉棘开始出现;15日龄时,尖吻鲈仔鱼的腹鳍开始发育,背肋和腹肋以软骨的形式生长,尾杆骨收缩,背鳍和胸鳍进入发育后期;19日龄时,尖吻鲈仔鱼脊柱骨化,胸鳍出现鳍棘,附肢骨骼发育接近完全;21日龄时,尖吻鲈仔鱼的背肋和腹肋开始骨化,尾鳍骨化基本完成,髓弓、脉弓、髓棘和脉棘也开始骨化;23日龄时,尖吻鲈仔鱼脊柱骨化完全,胸鳍发育完成,鱼体骨骼基础框架完成发育,鳍条开始骨化并出现分节,仔鱼完成变态.脊柱畸形首次出现在10日龄的尖吻鲈仔鱼中,至22日龄时畸形率占样本采集总量的8%,其中前期畸形的仔鱼在14~15日龄时基本被淘汰.结论]尖吻鲈仔鱼脊柱及附肢骨的发育顺序与其他鱼类基本一致,但发育时间节点有所不同.尖吻鲈仔鱼的骨骼发育畸形首次出现在10日龄左右,但主要集中在20~22日龄.

Skeleton development observation of Lates calcarifer larva fish

Objective]Skeleton development law of Lates calcarifer at larva stage was revealed to provide basic re-ference for relevant genetic research on skeleton development of L.calcarifer and exploration of fish fossils.Method]The formation and development characteristics of pectoral fin,dorsal fin,ventral fin,caudal fin and anal fin in the spine and appendicular skeleton of L.calcarifer larva fish0-23 day post hatching(DPH)]were continuously observed using carti-lage-bone double staining technique during development process.Result]The results showed that the 1 DPH larva fish was 1.70±0.10 mm long and the body was slender and straight;ossification did not start and appendicular skeleton did not appear.The spine of 3 DPH L.calcarifer larva fish bent naturally and started to develop,and the pectoral fins and primor-dium of caudal fins gradually formed.The end of notochord began to warp upward and the dorsal fins began to develop on 5 DPH.On 9 DPH,the notochord of L.calcarifer larva fish was bent,and neural arch and haemal arch began to form;urostyle upturned then caudal fins formed,the primordium of pectoral fins and dorsal fins wrinkles appeared,and anal fin started to develop.On 13 DPH,the development of pectoral fins and caudal fins in L.calcarifer larva fish almost comple-ted,and neural spines and haemal spines appeared.On 15 DPH,the ventral fins of L.calcarifer larva fish began to deve-lop and the dorsal and ventral ribs grew in the form of cartilage,and urostyle contracted;the development of dorsal fins and pectoral fins entered late development stage.On 19 DPH,ossification occurred in spine,and fins spine appeared in pectoral fins,the development of appendicular skeleton was to be completed.On 21 DPH,ossification happened in dorsal ribs and ventral ribs and the ossification of caudal fins almost completed;neural arch,haemal arch,neural spine and hae-mal spine were ossified.On 23 DPH,the ossification of spine,the development of pectora fins and the basic framework of fish skeleton fully completed;fin rays was ossified and branch pterygiophores appeared,and the metamorphosis of L. calcarifer larva fish completed.Spinal deformity first appeared in 10 DPH L.calcarifer larva fish.By 22 DPH,the defor-mity rate accounted for 8% of the total collected samples,among which the early deformed larva fish was basically elimi-nated at the age of 14-15 DPH.Conclusion]The spine and appendicular skeleton of L. calcarifer larva fish are in the same developmental sequence as other fish species,but the development time node is different.The skeletal development deformity of L.calcarifer larva fish first appears at the age of 10 DPH,and mainly appears at the age of 20-22 DPH.