Refinement of tickling protocols to improve positive animal welfare in laboratory rats.

积极的动物福利强调了动物拥有积极的经历对提高它们的生活质量的重要性。对于实验大鼠来说，挠痒痒被认为是积极改善其福利的一种有效和实用的方法。大鼠用人类的手挠痒痒是为了研究大鼠的积极情绪(情感)和超声波发声(USV)，通过模仿大鼠之间的嬉戏互动。标准的挠痒法是先用手指接触脖子后部，然后翻转老鼠，轻轻地把它按在仰卧位置，同时让手指快速移动，就像人类挠痒一样。包括我们自己在内的研究表明，当老鼠被人的手挠痒时，它们通常会发出50千赫的超声波发声(USV)，这被认为是对老鼠产生积极影响的信号。一般来说，老鼠觉得挠痒是有好处的，因为挠痒的老鼠更快地接近人类的手，并且可以被训练来执行挠痒的任务。然而，我们自己对老鼠挠痒的研究经验和其他可用的证据表明，老鼠和人类一样，对挠痒的反应有很大的不同。这表明，根据挠痒的方式和老鼠的个体特征，有些老鼠会将挠痒视为一种负面体验，这是有风险的。根据我们的数据，我们估计大约20%的老鼠可能会觉得挠痒痒是一种负面体验。这就要求改进挠痒协议，以确保挠挠的积极影响最大化，并将挠挠反应的个体差异降至最低。我们的总体目标是增加对老鼠挠痒的吸收，将其作为一种广泛使用的方法，以改善英国每年用于研究目的的大约18万只老鼠的福利。在这一总体目标下，我们建议通过测量雄性和雌性大鼠对挠痒的情感反应来完善挠痒方案。为了鼓励人们更广泛地接受挠痒，我们将研究挠痒对实验重复性的影响，并与最终用户合作，确定并限制在实践中使用挠痒。在这个总体目标中，我们将使用USV的记录和我们的情绪偏差验证测试，测试不同风格的挠痒如何影响大鼠的情绪反应。我们的假设是，与标准方案相比，老鼠将在积极情绪指标上表现出更一致的增长，这是一种“嬉戏挠痒方案”，强调人与老鼠之间的嬉戏互动，也最大限度地减少了钉住的使用。我们还假设，与标准方案相比，使用有趣的方案，挠痒痒的生物学后果的变量将较小。这将改进和增加研究的可重复性，在研究中，挠痒既可以作为标准的补充，也可以作为实验治疗。为了测试这一点，大鼠将被暴露在他们分配的治疗的进一步挠痒会话中，使用USV产品来评估它们的情绪反应。在最后的挠痒期之后，我们将对比挠挠状态下情绪反应的变异性和诸如行为焦虑以及压力和炎症的生理标记物等反应指标。在我们的第三个目标中，我们将与当地、国家和国际的研究人员(在他们的工作中使用老鼠)接触，以确定在他们的实验室中将挠痒作为一种有效和实用的积极社会财富形式的潜力。我们的沟通计划包括开发一个网站和成立一个利益攸关方小组，以了解在实践中使用挠痒的限制条件，并收集有关更广泛地将挠痒作为研究治疗或社会充实的数据。

Positive animal welfare emphasises the importance of animals having positive experiences to improve their quality of life. For laboratory rats, tickling is proposed as an effective and practical way to positively improve their welfare. Rat tickling with the human hand was developed to study positive emotions (affect) and ultrasonic vocalisations (USVs) in rats by mimicking playful interactions between rats. The standard tickling protocol involves initial finger contact with the nape of the neck before flipping the rat and gently pinning it in a supine position whilst making rapid finger movements just like in human tickling. Research including our own, has shown that when rats are tickled by a human hand they often produce 50 kHz ultrasonic vocalisations (USVs) which are thought to indicate positive affect in rats. Generally, rats find tickling rewarding as tickled rats are quicker to approach the human hand and can be trained to perform a task for tickling. However, our own research experience of rat tickling, and other available evidence, shows that rats, like humans, vary considerably in their response to tickling. This suggests that there is a risk that some rats perceive tickling as a negative experience depending on how tickling is performed and the rats' individual characteristics. From our data, we estimate that approximately 20% of rats may find tickling a negative experience. This calls for refinement of tickling protocols to ensure that the positive effects of tickling are maximised and to minimise individual differences in response to tickling. Our overall aim is to increase the uptake of rat tickling as a widely used approach to improving the welfare of the approximately 180k rats used annually in the UK for research purposes. Within this overarching aim, we propose to refine the tickling protocol by measuring male and female rats' affective responses to tickling. To encourage wider uptake of tickling we will study implications of tickling for experimental repeatability and work with end-users to identify and constraints to use of tickling in practice.Within this overall aim, we will test how different styles of tickling affect the emotional response of rats using recordings of USVs and our validated test of emotional bias. Our hypothesis is that rats will show a more uniform increase in indicators of positive emotion with a 'playful tickling protocol' that emphasises playful interaction between the human hand and the rat, and which also minimises the use of pinning relative to the standard protocol. We also hypothesise that the biological consequences of tickling will be less variable using a playful protocol relative to the standard protocol. This will refine and increase the repeatability of research where tickling is applied either as a standard enrichment or as an experimental treatment. To test this rats will be exposed to a further tickling sessions of their allocated treatment using USV production to assess their emotional responses. After a final tickling session we will contrast the variability in emotional response to the tickling regimes against response measures such as behavioural anxiety and physiological markers for stress and inflammation. In our third objective, we will engage with researchers (who use rats in their work) locally, nationally and internationally to determine the potential of applying tickling as a valid and practical form of positive social enrichment in their laboratories. Our communication plan includes development of a web-site and forming a stakeholder group to understand constraints to use of tickling in practice and to gather data on the wider use of tickling as a research treatment or as a social enrichment.