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Studies on artificial control of reproductive cycle in fishes.

鱼类生殖周期的人工控制研究。

基本信息

批准号：
63480068
负责人：
FURUKAWA Kiyoshi
金额：
$ 4.54万
依托单位：
Faculty of Agriculture, University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

1. The effects of water temperature and photoperiod on the reproductive activity were investigated in two fishes, freshwater cyprinid fish Honmoroko (Gnathopogon caerulescens) and seawater dragonet Tobinumeri (Repomucenus beniteguri), as new species. (1) Honmoroko showed a similar response with goldfish to environmental factors, that is, photoperiodism was dependent on temperature and high temperature suppressed gonadal maturation. Short daylength depressed maturation more effectively as water temperature increased. In autumn when temperature decreased, gonadal recrudescence started with the diminution of inhibitory effect of short daylength. Though maintenance of maturation needed long photoperiod in the spawning season of spring to early summer,high temperature in summer suppressed the gonadal activity when daylength was still long. (2) Tobinumeri began to spawn as temperature rose (above 18ﾟC) in spring, and stopped spawning temporally with further rise of temperature (above 28ﾟC). … More Spawning resumed with the fall of temperature in autumn (below 24-25ﾟC), and spawning continued below 14ﾟC. It was noticed experimentally that unlike honmoroko, long photoperiod had suppressive effect on gonadal activity in this fish.2. Rainbowtrout broodstock were reared under long photoperiods, 16L, 18L and 20L for about one year from March. Gonadal recrudescence advanced under long daylength, and at 16L females reached spawning peak in October whereas the peak of other groups were November. The spermiation of males of three groups started one month earlier than those of natural condition group. It was suggested that long photoperiod treatment can compensate the delay of male maturation which is a problem of many hatcheries where early spawning females have been selected.3 Two experiments were conducted with goldfish. One was long term exposure to 24ﾟC or 16ﾟC combined with 16L or 12L, and the other was short exposure to four regimes transferred from natural condition several times in a year. These experiments revealed that photoperiodism became clearer as temperature increased, but enhancement of gonadal maturation by long photoperiod was transient. It was also observed that high temperature and long photoperiod was suppressive to gonads in female but not in male.4. As to the plasma level of maturation related hormones in honmoroko and goldfish, estradiol-17beta of female fish and testosterone of male fish were correlated with degree of gonadal maturation but gonadotropin contents increased with the temperature regardless of maturational stage. Less

1. 以淡水鲤Honmoroko （Gnathopogon caerulescens）和海水龙Tobinumeri （Repomucenus beniteguri）为新种，研究了水温和光周期对两种鱼类生殖活动的影响。(1)本氏子对环境因素的反应与金鱼相似，即光周期依赖于温度，高温抑制性腺成熟。随着水温的升高，较短的日长更有效地抑制了成熟。在气温下降的秋季，随着短日照抑制作用的减弱，性腺开始复发。在春季至初夏产卵季节，虽然维持成熟需要较长的光周期，但夏季高温对日长较长的性腺活动有抑制作用。(2)春季温度升高（高于18 C）时，双鱼开始产卵，温度进一步升高（高于28 C）时，双鱼暂时停止产卵。随着秋季温度的下降（低于24-25ºC），产卵量恢复较多，低于14ºC继续产卵。实验发现，长光周期对赤子鱼的性腺活性有抑制作用，与赤子鱼不同。从3月份开始，在长光期16L、18L和20L条件下饲养虹鳟鱼约一年。在长日照条件下，性腺复发期提前，16L雌鱼在10月达到产卵高峰，其他类群在11月达到产卵高峰。三组雄鼠的精子开始时间比自然状态组早一个月。结果表明，长光周期处理可以弥补雄性成熟的延迟，这是许多孵化场选择早产卵雌性的问题用金鱼做了两个实验。一种是长期接触24或16 C结合16L或12L，另一种是短期接触从自然状态转移的四种方案，一年几次。这些实验表明，随着温度的升高，光周期变化变得更加明显，但长光周期对性腺成熟的促进是短暂的。高温和长光周期对雌虫性腺有抑制作用，而对雄虫性腺无抑制作用。在赤子鱼和金鱼的血浆成熟相关激素水平中，雌鱼的雌二醇-17 β和雄鱼的睾酮水平与性腺成熟程度相关，但无论成熟期如何，促性腺激素含量都随温度升高而升高。少