Inhibitory Effects of Testosterone on Downstream Migratory Behavior in Masu Salmon, Oncorhynchus masou
Inhibitory Effects of Testosterone on Downstream Migratory Behavior in Masu Salmon, Oncorhynchus masou
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睾酮对马苏鲑鱼下游洄游行为的抑制作用
DOI：
10.2108/zsj.17.863
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
K. Aida
中科院分区：
文献类型：
--
作者：
A. Munakata;M. Amano;K. Ikuta;S. Kitamura;K. Aida
摘要 利用人工水道研究了睾酮（T）对一岁马苏鲑鱼（Oncorhynchus masou）下游洄游行为的影响。在实验1中，22和19只小鲑鱼被植入仅含有500μg T或媒介物的医用硅胶管胶囊。这些组被一起转移到人工水道的上层池塘，人工水道通过鱼道与下层池塘相连。然后观察下游迁徙行为1周。在实验2中，将T500μg、T50μg和T5μg处理的小鲑鱼、对照小鲑鱼和早熟雄性转移至水道上游池塘，观察下游迁徙行为2个月。在实验3中，40只小鲑鱼被植入含有500μg T的胶囊或仅含有媒介物。将这些群体分别转移至水道上游池塘并观察下游迁徙行为3周。在每个实验中，注射 T 都会导致血浆 T 水平在生理水平内增加。在实验1中，对照组下游迁移行为的频率为89.5%，T500μg处理组为31.8%。在实验2中，T500μg和T50μg处理组的频率低于对照组。 T5μg植入未能抑制下游迁移行为。没有观察到早熟的雄性会沿着水道走下去。实验3中，对照组和T500μg处理组的下游迁移行为频率分别为100%和40%。在每个实验中，T500μg处理的未表现出下游迁徙行为的小鲑鱼的血浆T水平高于迁徙者。这些结果表明马苏鲑鱼的下游洄游行为受到T.鲑鱼生理水平的抑制。
Abstract The effects of testosterone (T) on downstream migratory behavior of yearling masu salmon, Oncorhynchus masou, were studied during its downstream migratory period using artificial raceways. In experiment 1, 22 and 19 smolts were implanted with a medical silicone tube capsules containing 500μg of T or vehicle only. These groups were transferred together to the upper pond of artificial raceway which was connected to the lower pond through fish-way. Downstream migratory behavior was then observed for 1 week. In experiment 2, T500μg-, T50μg-, and T5μg-treated smolts, control smolts, and precociously mature males were transferred to the upper pond of the raceway and downstream migratory behavior was observed for 2 months. In experiment 3, 40 smolts were implanted with capsules containing 500μg of T or vehicle only. These groups were transferred separately to the upper ponds of raceways and downstream migratory behavior was observed for 3 weeks. In each experiment, injection of T caused increases in plasma T levels within physiological levels. In experiment 1, frequency of downstream migratory behavior was 89.5% in the control group and 31.8% in the T500μg-treated group. In experiment 2, the frequency was lower in the T500μg- and T50μg-treated groups than in the control group. T5μg implantation failed to inhibit downstream migratory behavior. Precocious males were not observed to go down the raceway. In experiment 3, frequency of downstream migratory behavior of the control group and the T500μg-treated group was 100 and 40%, respectively. In each experiment, plasma levels of T in T500μg-treated smolts which did not show downstream migratory behavior was higher than those of migrants. These results indicate that the downstream migratory behavior of masu salmon smolts is inhibited by physiological levels of T.