施氏鲟的胚胎及胚后发育研究

Embryonic and larval development of Amur sturgeon Acipenser schrenckii

施氏鲟的成熟卵为典型的多黄卵，受精后胚盘隆起不明显，卵裂为特殊的辐射裂，与多数硬骨鱼类有明显差别，与两栖类卵裂相似，且卵裂方式有明显的硬骨鱼类盘状卵裂的痕迹。施氏鲟的胚胎发育可分为受精卵、卵果期、囊胚期、原肠期、卵黄栓期、神经胚期、视泡形成期、心脏形成博动期和孵出期；胚后发育则分为卵黄囊期仔鱼、晚期仔鱼和稚鱼期。水温１７～１９℃时，施氏鲟胚胎发育历时９５～１０４ ｈ，总积温需用 １７１０～１８７２℃·ｈ。胚后发育水温为２０～２３℃，刚孵出的仔鱼全长９．４２～１１．０ ｍｍ，体重２９～３９ ｍｇ；出膜后第 ３０天的平均全长４２．８ ｍｍ，平均体重３．２ ｇ，其外部形态与成鱼基本一致。

Two parent Amur sturgeon Acipenser schrenskii (male, BW 14 kg; female, BW 44 kg) were injected with LRH-A, and the eggs were taken out and fertilized artificially, then incubated. The observation shows that the mature eggs of Amur sturgeon are rich in yolk; after fertilization, the blastodiscs swell slightly and their cleavage pattern shows radial holoblastic cleavage and is similar to that of amphibian, but not obviously different with many other fishes; however, the disc cleavage is something like that of bony fish. Before the embryos hatch, it takes 9 embryonic development stages, including cleavage, blastula, gastrula, yolk plug, neurula, formation of optic bud and beating of heart, when the water temperature being 17 -- 19℃, the total accumulative temperature 1710 -- 1 872℃． h and taking time 95 -- 104 h. The larval development includes 3 stages which are yolk-sac stage larva, later-stage larva and fry, when the water temperature being 20-- 30℃. The just- hatching larvae have a total length range of 9. 42 -- 11. 0 mm. Thirty days later, the average TL is 42. 8 mm, average BW 3. 2 g, and the organs all finished their differentiation and the larval appearance almost looks like their adult' s.