Control of final gonadal maturation in the hybrid sturgeon, bester.

对成年雄性F1鲟鱼Bester(Huso Huso L.雌性×Acipenser ruthenus L.雄性)的睾丸发育与血清性类固醇水平的关系进行了每月一次的检查。精子发生持续1年，减数分裂一般从9月开始，精子发生在11月，尽管每月采样的鱼的睾丸发育阶段有相当大的差异。在冬季的几个月里，直到4月，睾丸的发育仍在缓慢地进行。鱼类无自发受精现象，5月以后支持细胞吞噬空腔变大。雄激素水平在精子发生过程中增加，并在整个受精前阶段保持在较高水平。在退化期，11-酮睾酮浓度下降到低水平，而睾酮(T)水平保持在较高水平。在整个生殖周期中，17α，20β-二羟基-4-孕烯-3-酮(DHP)的血清浓度都很低。基于这些结果，建议使用…在1年的采样期内，观察了成年雌鼠血清雌二醇-17β(E_2)-T、DHP和卵黄蛋白原(VTG)水平的变化与卵巢发育的关系。在鱼类的卵母细胞发育过程中发现了相当大的差异。发育前阶段的卵母细胞一般随着第一批卵母细胞的退化而开始发育。卵黄发生个体卵巢由直径0.6~2.6 mm的较高级卵母细胞组成，卵黄发生后卵母细胞体积最大，双生小泡向动物极部迁移。具有迁移核的卵母细胞在越冬期间保持不变，4-5月开始大规模退化，没有生发泡破裂(GVBD)或排卵。E_2、T和VTG水平的季节变化与卵子发生的推进密切相关。卵黄发生后(游走核)，E_2水平由2~4 ng/ml降至1~2 ng/ml，VTG由4~10 ng/ml降至0.2~0.5 ng/ml，而T水平仍较高。相比之下，在整个生殖周期中，血清DHP水平一直很低。这些结果表明，诱导人工繁殖的适宜时间为10-11月至4-5月，此时卵母细胞处于发育的后期。较少

Testicular development in the adult male F1 sturgeon hybrid, the bester (Huso huso L.female x Acipenser ruthenus L.male) was examined monthly in relation to serum sex steroid levels. Spermatogenesis lasted for 1 year, with meiosis generally starting September and spermatogenesis in November, although there was considerable variation in testiculal developmental stages between fish sampled monthly. Testicular development continued, slowly, during the winter months until April. Fish did not exhibit spontaneous spermiation, and phagocytotic cavity of Sertoli cells became prominent from May onwards. Androgen levels increased during spermatogenesis and remained high throughout the pre-spermiation period. In the degeneration stage, 11-ketotestosterone concentrations declined to low levels, b while testosterone (T) levels remained high. The serum concentration of 17alpha, 20beta-dihydroxy-4-pregnen-3-one (DHP) was low throughout the reproductive cycle. Based on these resultss, it is suggested … More that the time appropriate for induction of final maturation would be from November-December to April when the testes are in the late stage of development.Changes in serum levels of estradiol-17beta (E_2)T,DHP and vitellogenin (VTG), in cultured adult female were examined in relation to ovarian development during a 1-year sampling period. Considerable variationsin oocyte development were found among fish. Oocytes at previtellogeenic ssatge generally started to develop conconitantly with the degeneration of the first batch ofoocyte. In vitellogenic individuals, ovaries were comprised of more advanced oocytes with diameter ranging from 0.6 to 2.6 mm and in the post-vitellogenic class, oocytes attained their largest size while the geminal vesicle was migrating towards the animal pole. Oocytes with a migrating nucleus were maintained during the winter period and massive degeneration started in April-May without germinal vesicle breakdown (GVBD) or ovulation occurring. Seasonal changes in E2, T and VTG levels were well correlated with the advancement of oogenesis. Their levels increased during vitellogenesis, whereas in the posstvitellogenic (migratory nucleus) stage the levels of E2 declined from 2-4 ng/ml to 1-2 ng/ml and VTG from 4-10 ng/ml to 0.2-0.5 ng/ml while T levels remained high. In contrast, serum levels of DHP were constantly low throughout the reproductive cycle. These results indicate that the time appropriate for induction of artificial reproduction would be from October-November to April-May when the oocytes are in the late stages of the development. Less