Department of Fisheries, Faculty of Natural Resources, Islamic Azad University, Lahijan Branch, Lahijan, Guilan, Iran.
Anim Reprod Sci. 2012 Jun;132(3-4):213-22. doi: 10.1016/j.anireprosci.2012.05.011. Epub 2012 May 24.
The objective of this study was to control the reproductive cycle of pikeperch (Sander lucioperca) through determining the effects of different photoperiods and handling stress on the reproduction quality, timing and quality of spawning, fertilization, sex steroids, and cortisol concentrations. In this study, 72 pikeperch broodstocks with an average weight of 1367 ± 55.3 g were exposed to different photoperiods including constant light (24L:0D), constant darkness (0L:24D), and 12 h of light, 12 h of darkness (12L:12D) for 40 days. Half of the broodstocks of each photoperiod treatment were exposed to handling stress at a specific time of the day. Applying different photoperiods caused changes in the timing of broodstocks' spawning, so that fish under 24L:0D spawned earlier than those of other photoperiods, and stressed fish of the 0L:24D photoperiod had a delayed spawning compared to others. Also, the spawning of the broodstocks at different photoperiods which were exposed to handling stress was either delayed or did not occur at all. The highest and lowest spawnings were observed in the morning and at night, respectively. Fertilization percentage, number of eggs per gram, sex steroids including estradiol, progesterone, and testosterone, as well as cortisol and calcium concentrations did not show any significant difference in different photoperiods and handling stress. In stressed males of the 24L:0D photoperiod, there only was a significant decrease of testosterone concentration compared to the beginning of the experiment. Results indicated that the spawning performance of pikeperch broodstocks could be considerably stimulated using an effective photoperiod. Similarly, pikeperch broodstocks in culture systems are usually affected by handling stress, and this stress could lead to a poor reproductive performance and inhibition of spawning.
本研究旨在通过确定不同光周期和处理应激对繁殖质量、产卵时间和质量、受精、性类固醇和皮质醇浓度的影响，来控制欧鲈（Sander lucioperca）的繁殖周期。在这项研究中，将 72 尾平均体重为 1367±55.3g 的欧鲈亲鱼暴露于不同光周期下，包括连续光照（24L:0D）、连续黑暗（0L:24D）、12L:12D（光照 12 小时，黑暗 12 小时）持续 40 天。每个光周期处理的一半亲鱼在一天中的特定时间暴露于处理应激下。应用不同的光周期导致亲鱼产卵时间发生变化，因此 24L:0D 光照下的鱼比其他光周期下的鱼更早产卵，而处于 0L:24D 光照下的应激鱼比其他鱼产卵时间延迟。此外，暴露于处理应激下的处于不同光周期的亲鱼的产卵要么延迟，要么根本不发生。产卵高峰期出现在早晨和晚上。在不同的光周期和处理应激下，受精率、每克卵数、性类固醇（包括雌二醇、孕酮和睾酮）以及皮质醇和钙浓度均无显著差异。在 24L:0D 光周期的应激雄性中，与实验开始时相比，只有睾酮浓度显著降低。结果表明，使用有效的光周期可以显著刺激欧鲈亲鱼的产卵性能。同样，养殖系统中的欧鲈亲鱼通常会受到处理应激的影响，这种应激会导致繁殖性能下降和产卵抑制。
