热休克和水静压刺激诱导三倍体硬头鳟(Oncorhynchus mykiss)对比研究

COMPARISON OF HEAT AND HYDROSTATIC PRESSURE SHOCKS TO INDUCE TRIPLOIDY IN STEELHEAD TROUT(SALMO GAIRDNERI)

雌性三倍体鲑鳟鱼已知是不育的,因而有利于水产养殖。本研究旨在对多种温度和水静压刺激处理诱导三倍体硬头鳟(Oncorhynchus mykiss的一种溯河回游类型)的效果加以对比。热休克和水静压刺激在各组硬头鳟卵受精后25分钟开始施行。热休克处理所用温度为26—36℃,持读1.25～20分钟;水静压处理所用压力为5.5～8.3×10~4KPa(1KPa=0.145psi)持续2～6分钟。三倍体的诱导率通过红血球细胞核长径的测定来计算。在26℃温度下持续20分钟的热休克处理和在7.6×10~4kPa压力下持续6分钟的水静压刺激诱导出100％的三倍体比率(triploid rate),但是各组卵的成活率却与处理的强度成负的相关关系。因而三倍体产量(triploid yield)(即三倍体的诱导率与孵出时的成活率的乘积)在26℃下持续10分钟的热休克或6.9×10~4KPa下持续6分钟的水静压刺激处理时为最好,分别是50.3％和49.9％。

Triploid female salmonids are known to be sterile and thus may offer certain advantages for aquaculture. This study was conducted to compare various temperature and pressure shocks for the induction of triploidy in steelhead trout, an anadromous form of Oncorhynchus mykiss.Thermal of hydrostatic pressure shocks were administered 25 min post—fertilization to groups of stcelhead trout eggs. Thermal shocks ransed from 26 to 36℃, lasting from 1.25 to 20min. Pressura shocks ranged from 5.5 to 8.3×10~4 kPa, lasting from 2 to 6 min. Triploid induction was evaluated by measurement of the major axis of erythrocyte nuclei. Triploid rates of 100% were produced by heat shock at 26℃ for 20 min and by pressure shock of 7.6×10~4 kPa for 6 min. Survival, however, was inversely correlated to the intensity of the treatments, thus trlploid yields, calculated as the product of the trlploid rate and the numbers surviving to hatch, expressed as percentage of the number of eggs origtually present in the groups, were best when a heat shock of 26℃ for 10 min or hydrostatic pressure treatment at 6.9×10~4 kPa for 6 min was applied (50.3% and 49.9%, respectively).