摘要
草鱼在人工培育条件下,一年可以进行多次催情产卵。草鱼一年多次产卵的生物学基础主要是: (1)成熟草鱼卵母细胞发育的不完全同步性。由于卵母细胞由第Ⅲ时相过渡到第Ⅳ时相不是完全同步,所以,在第一次催产产空后的卵巢中保留有相当数量第Ⅲ时相卵母细胞,它们经过人工培育一段时间后,能够发育成熟而在第二次催产时产出。(2)第一次催产后保留在卵巢中的第Ⅲ时相卵母细胞向第Ⅳ时相发育的过程中,呈现明显的AKP酶活性反应而没有ACP酶活性反应,表明这些卵母细胞正在进行着旺盛的物质代谢活动,生长发育正常。(3)第一次催产后垂体间叶嗜硷性细胞还有一部份保留着分泌颗粒,表明促性腺激素的分泌活动尚在持续进行,这是第Ⅲ时相卵母细胞能够发育成熟的重要生理因素。
The technique of multiple spawning of the grass carp is widely practised in artificial propagation. The biological basis consists of:(1) The development of oocytes in the ovary of the brood fish is not completely synchronous. After the first spawning is artificially induced, what remain in the ovaries are some quantities of oocytes of the third phase. These oocytes continue to develop into the fourth phase after a period of intensive feeding of the brood fish. The fish is, then, ready for the successive spawning under artificial propagation.(2) During the period when the oocytes of the third phase develop into the fourth phase there is an active reaction of AKP, but none of ACP. This indicates that the metabolism of these oocytes is in progress.(3) A portion of the basophilic cells in the mesoadenohypophysis retain their secretory granules, indicating that the gonadotropin-secreting activity is still going on. This constitutes the main physiological factor governing the further development of the third phase oocytes into the ripe ova.
