虹鳟(Oncorhynchus mykiss)选育群体的血清类固醇激素周年变化

SEASONAL CHANGES OF SERUM STEROID LEVELS IN RAINBOW TROUT (ONCORHYNCHUS MYKISS) OF THE SELECTION POPULATION

采用放射性免疫(RIA)和组织学切片技术,系统地研究了虹鳟(Oncorhynchus mykiss)选育群体的血清性类固醇激素周年变化与性腺发育特点的关系,以及血清中性类固醇激素雌二醇(E2)和睾酮(T)在雌雄亲本中的周年变化规律和生理作用。结果表明,虹鳟性腺发育可划分为6期。雌鱼血清中E2在10月(V期性腺)达到峰值,T浓度在11月达到峰值,而进入繁殖期后(11—12月)E2开始下降。雄鱼血清T浓度在11月达到最大值,E2在6月份达到峰值,在11月之后T开始下降。在各月份,雌鱼E2浓度水平远高于雄鱼,而雄鱼T浓度个别月份低于雌鱼。这些研究揭示出,测定血清性类固醇激素浓度水平可用于准确判断鱼类的生殖状态,且可为虹鳟家系选育出早熟亲本群体提供重要技术依据。

Aiming to finding the relationship between seasonal changes of serum steroid levels and developmental stages of gonad, and investigation the seasonal cycles of serum testosterone （T） and estradiol （E2） levels, we measured rainbow trout of the selection population using RIA and histology slice technique methods in this study. Our results showed that the development of gonad in rainbow trout included VI stages. The females had one E2 peak value in October （in the V stage）, and the T level in females changed follow with that of E2 and reached the highest value in November. However, E2 level was decreased just in the spawning season. The males had one T peak value in November and one E2 peak value in June. Nevertheless, T level was decreased after high-peak stage. The E2 level in females was always higher than males obviously in annual cycle. However, T level in males was lower than females in some months. Together, these findings showed that the levels of serum steroid had relationship with gonad development, which offered us the technology support to the selection of the early-maturing population in rainbow trout.