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首页> 外文期刊>The Progressive Fish-Culturist >Effect of three hatchery lighting schemes on indices of smoltification in chinook salmon
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Effect of three hatchery lighting schemes on indices of smoltification in chinook salmon

机译：三种孵化场照明方案对切努克鲑鱼糖化指数的影响

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摘要

This experiment examined whether photoperiodic changes induce chinook salmon Oncorhynchus tshawytscha to alter various indices of smoltification. The effect of 24 h light, a constant photoperiod of 9 h light: 15 h dark (9L:15D), and a naturally increasing photoperiod on plasma levels of thyroxine and cortisol, hematocrit, condition factor (K), and hepatosomatic index (HSI) was tested during the period of smoltification in chinook salmon. The 24-h-light group grew faster than the other two groups, but was significantly larger than one of the two groups on only three sampling dates. Mean plasma thyroxine and cortisol levels were highest in the naturalphotoperiod group and lowest in the 9L:15D group. Mean plasma cortisol levels increased significantly in the increasing and 9L:15D photoperiod groups but were unchanged in the continuouslight group. Mean HSI decreased faster in the natural-photoperiod group than in the other two groups. Mean hematocrit did not change in the natural-photoperiod group but decreased in the other two groups. Mean K decreased in the natural-photoperiod and 24-h-light groups, but not in the 9L: 15D group. The natural-photoperiod group clearly showed a more coordinated and complete smoltification based on the indices measured: highest mean and peak levels of both thyroxine and cortisol, greatest decrease in HSI, greatest decrease in K (along with the 24-h-light group), and least decrease in hematocrit. These results show that a natural photoperiod is beneficial and that continuous light or a short, unchanging photoperiod are detrimental to smoltification in chinook salmon, Hatcheries should account for photoperiodic effects when raising chinook salmon, particularly indoors.
机译：该实验检查了光周期的变化是否诱导了奇努克鲑Oncorhynchus tshawytscha改变了各种糖化指数。 24小时光照，9小时光照恒定：黑暗15小时（9L：15D）以及自然增加的光周期对血浆甲状腺素和皮质醇，血细胞比容，条件因子（K）和肝素指数（HSI）的影响）在chinook鲑鱼的糖化过程中进行了测试。 24小时光照组的生长速度快于其他两组，但仅在三个采样日期显着大于两组之一。在自然光周期组中平均血浆甲状腺素和皮质醇水平最高，而在9L：15D组中最低。在增加的和9L：15D的光周期组中，平均血浆皮质醇水平显着增加，而在连续光照组中则没有变化。自然光周期组中的平均HSI下降速度快于其他两组。在自然光周期组中，平均血细胞比容没有变化，而在其他两组中，平均血细胞比容却下降了。在自然光周期和24小时光照组中，平均值K下降，但在9L：15D组中，平均值K并未下降。根据测量的指标，自然光周期组明显显示出更加协调和完全的熔融：甲状腺素和皮质醇的最高平均水平和峰值水平，HSI的最大下降，K的最大下降（以及24小时光照组） ，血细胞比容下降最少。这些结果表明，自然光周期是有益的，连续光照或短而不变的光周期不利于奇努克鲑鱼的软化。孵化场应在养成奇努克鲑鱼时考虑光周期效应，特别是在室内。

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