The cultivation method of healthy marine fish seedlings using the heat shock factor as an indicator

研究了健康鱼苗生产发展过程中环境胁迫因素的一些指标。此外，我们还研究了一些鱼类从幼虫到幼鱼一生中应激反应的个体成因变化。起初，大鳞龙幼鱼受到低氧、高温和低温、低盐度和高盐度的影响。比较了热休克因子（HSF）比活性、糖皮质激素受体（GR）比活性和皮质醇水平作为应激指标。应激后皮质醇浓度升高，HSF和GR比活性逐渐升高。对应激暴露具有高耐受性和低耐受性的鱼类也被选择并确定为应激指标。高耐受性鱼的HSF和GR活性高于低耐受性鱼。HSF、GR和皮质醇水平是检查鱼类的良好指标。其次，研究了大鳞鱼（Pagrus major）、橄榄副鱼（palichthys olivaceus）、红鳍金枪鱼（Takifugu rubbripes）和东方棘鱼（Thunnus orientalis）的幼鱼和幼鱼的耐缺氧和应激反应的发生机制。结果表明，在屈折期和屈折期前后，鱼类的代谢率和能量代谢最高，因此耐缺氧能力最低。最后，在幼虫和幼鱼中研究了一些应激耐受性的个体变化及其对应激耐受性的反应。结果发现，在幼苗期，所有耐受性和皮质醇水平均有所增加。实验还测试了皮质醇浸泡对幼虫各种应激耐受性的影响。皮质醇浸泡后，成活率、皮质醇浓度和GR活性对应激源的反应均有增加的趋势。因此，这表明皮质醇在适应环境压力源中起着重要作用。

Some indicators of environmental stressors were examined in the development of healthy fish seedling production. In addition, ontogenic changes in the stress response to environmental stressors were studied in some kinds of fish in their lifespan from larvae through the juvenile stage. At first, Pagrus major juveniles were subjected to low oxygen, high and low temperatures, hypo-and hyper-salinity. The specific activities of heat shock factor (HSF), glucocorticoid receptor (GR) and cortisol level as stress indicators in the fish were compared. The cortisol concentration was increased just after stress exposure, but the specific activities of HSF and GR gradually tended to become elevate. Fish showing both high and low tolerance to stress exposure were also selected and determined to be stress indicators. HSF and GR activities in high tolerance fish tended to be higher than those in the low tolerance fish. The HSF, GR and cortisol level were suggested to be good indicators to check in fish. Next, the ontogeny of hypoxia tolerance and stress response were studied in Pagrus major, Paralichthys olivaceus, Takifugu rubripes and Thunnus orientalis larvae and juveniles. The results indicated that around the stages of flexion and post-flexion larvae in fish, metabolic rates and/or energy metabolism were the highest, and consequently hypoxia tolerance was the lowest. Finally, ontogenic changes in some stress tolerances and the response to this were examined in larvae and juveniles. It was found that at the early juvenile stage all of the tolerances and the cortisol level were increased. The effects of cortisol immersion on various stress tolerances in larvae were also tested. The response of the survival rate, cortisol concentration and GR activity to stressors showed a tendency to increase as a result of cortisol immersion. It was therefore suggested that cortisol has an important role in adaptation to environmental stressors.