The physiology of social and environmental stress in fish

我的研究计划的长期目标是了解鱼的应激生理学。鱼类(和其他动物)经常面临威胁其动态平衡的物理和/或生物因素。作为对这些应激源的反应，启动了一系列协调的行为、神经内分泌和细胞事件，使动物能够克服威胁。尽管应激反应对个体和群体的健康/生存很重要，但我们对它们如何被调节并与其他生理系统整合的了解仍然有限，特别是在慢性应激期间。 这项拟议的研究将使用慢性社会压力作为一个系统来研究压力轴的调节。鲑鱼幼鱼建立社会等级，在这种等级中，较高等级的个体以牺牲较低等级的鱼为代价获利(例如，生长得更好)。我们将研究从属鱼类肝脏新陈代谢的调节，以了解慢性压力如何影响肝脏，以及这反过来如何影响鱼类的生长。我们还将试图了解如何以及为什么从属鱼类循环中的皮质醇(应激激素)水平持续升高，但同时，从属鱼类无法进一步提高皮质醇以应对额外的急性应激源。最后，我们将探索母体应激影响后代应激反应的可能性--这在哺乳动物中得到了很好的证实，但在鱼类中几乎没有受到关注。为了补充我们在社会压力方面的工作，我们将通过表征皮质醇在调节酸碱反应中的作用来研究环境应激源。 总的来说，这项拟议的研究将促进我们对鱼类应激生理学的基础知识。鱼在自然环境(如钓鱼、有毒物质、气候变化、酸性水加上捕食、社会相互作用、水流变化)和水产养殖环境(如高饲养密度、处理)中都会受到多种压力。了解它们如何应对这些多重压力，是更好地管理野生和水产养殖种群的关键。

The long-term objective of my research program is to understand the physiology of stress in fish. Fish (and other animals) regularly face physical and/or biological factors that threaten their homeostasis. In response to such stressors, a co-ordinated suite of behavioural, neuroendocrine, and cellular events is initiated to enable the animal to overcome the threat. Despite the importance of stress responses to the health/survival of individuals and populations, our knowledge of how they are regulated and integrated with other physiological systems remains limited, particularly during chronic stress. The proposed research will use chronic social stress as a system in which to study regulation of the stress axis. Juvenile salmonid fish establish social hierarchies in which individuals of higher rank profit (e.g. grow better) at the expense of lower-ranking fish. We will study the regulation of metabolism in the liver of subordinate fish to understand how it is affected by chronic stress and how this, in turn, affects fish growth. We also will try to understand how and why circulating cortisol (stress hormone) levels in subordinate fish are persistently elevated but at the same time, subordinate fish are unable to further elevate cortisol in response to an additional, acute stressor. Finally, we will explore the possibility that maternal stress affects offspring stress responses - this is well-established for mammals but has received little attention in fish. To complement our work on social stress, we will examine an environmental stressor by characterizing the role of cortisol in regulating acid-base responses. Collectively, the proposed research will advance our fundamental knowledge of the physiology of stress in fish. Fish can be subjected to multiple stressors both in the natural environment (e.g. angling, toxicants, climate change, acid water plus predation, social interactions, changes in water flow) and in aquaculture settings (e.g. high holding density, handling). Understanding how they respond to these multiple stressors is key to better managing both wild and aquaculture populations.