Investigation of behavioural and physiological responses to fin-clipping in zebra fish

斑马鱼被广泛用作研究动物。斑马鱼作为实验动物的使用正在增加，主要是因为斑马鱼具有特殊的特征，使它们非常适合进行胚胎发育的遗传研究，并在生物医学、药理学和遗传学研究中作为哺乳动物的替代品正变得越来越受欢迎。遗传分析需要一个组织样本，在斑马鱼中，组织样本是通过剪鳍获得的，即手术切除部分尾鳍。这一手术是在全身麻醉下进行的，但在手术后不提供疼痛缓解。因此，经历这一过程的鱼一旦醒来就有可能经历疼痛。最近的研究为不同种类的鱼(包括斑马鱼)感受疼痛的能力提供了解剖学、神经生理学和行为学方面的证据。剪断尾鳍已被证明可以在各种鱼类中诱导疼痛相关反应。然而，剪鳍可能会带来疼痛，从而改变斑马鱼的行为和生理，这一点还没有被研究过。由于每年都有大量斑马鱼接受这一程序，我们希望这项研究将有助于改进这一程序，如果需要的话，并在研究中改善鱼类的福利。通过录像和分析尾鳍剪断鱼的行为和测量生理参数(如盖骨/呼吸频率和非侵入性应激激素皮质醇测量)，并将这些参数与适当的对照鱼进行比较，我们将确定可能反映对伤害的痛苦反应的潜在行为和生理指标。我们还将开发行为测试，以评估割鳍是否会引起斑马鱼的情绪反应，表现为动机和注意力的变化。例如，这些测试将测量对新物体的恐惧反应，以及对不透明覆盖物等浓缩物品的使用，据报道，这两种物品在遭受疼痛的鱼类中都会减少。研究的最后一部分旨在调查止痛药(即吗啡)对研究第一部分确定的行为和生理疼痛指标的影响，以验证这些指标确实是由疼痛引起的。这项研究的结果可能会潜在地影响未来用于基因分析的组织收集政策，并导致对这一程序的改进，例如使用适当的止痛药。在这项研究中确定的疼痛指标可以用于进一步的研究，也可以整合到疼痛评估方案、监测系统中，并作为评估止痛药效果的参数。这项研究的结果还可以应用于其他可能令人痛苦的程序，从而改善世界各地实验室鱼类的福利。

Zebra fish are extensively used as research animals. Use of zebra fish as experimental animals is increasing, mainly because zebra fish have particular characteristics that make them very suitable for genetic research on embryo development and are becoming popular as a replacement for mammals in biomedical, pharmacological and genetic research. Genetic analysis requires a tissue sample, which in zebra fish is obtained through fin clipping, i.e. the surgical removal of part of the caudal fin. This procedure is carried out under general anaesthesia but without the provision of pain relief following the procedure. Thus, there is potential for fish undergoing this procedure to experience pain once they wake up. Recent studies have provided anatomical, neurophysiological and behavioural evidence for the capability of different species of fish (including zebra fish) to experience pain. Tailfin clipping has been proven to induce pain-associated responses in various fish species. However, the potential of fin clipping to be painful and therefore produce changes in the behaviour and physiology of zebra fish has not been investigated. As large numbers of zebra fish undergo this procedure every year we hope this study will help refine this procedure if required and improve fish welfare in research. By video-recording and analysing the behaviour and measuring physiological parameters (such as operculum/respiratory rate and non-invasive stress hormone -cortisol- measurement) of tailfin-clipped fish and comparing these parameters with appropriate control fish, we would identify potential behavioural and physiological indicators that might reflect a painful response to the injury. We will also develop behavioural tests which would assess if fin clipping evokes an emotional response in zebra fish, manifested as changes in motivation and attention. These tests will measure, for example, the fear response to a novel object and the use of enrichment items such as an opaque cover, both of which have been reported to be decreased in fish suffering from pain.The final part of the study would aim at investigating the effect of painkillers (i.e. morphine) on the behavioural and physiological pain indicators identified in the first part of the study, in order to validate that these indicators are indeed caused by pain. The results from this study could potentially influence future policies for tissue collection for genetic analysis and lead to the development of refinements for this procedure, for example with the use of appropriate pain relief. Pain indicators identified during this study could be used in further studies and could also be integrated into pain assessment protocols, monitoring systems and as parameters for assessing painkiller efficacy. Findings from this study could also be implemented in other potentially painful procedures which would result in improving the welfare of laboratory fish worldwide.