Breathless Birds: Does air hunger impact the welfare of poultry at slaughter?

喘不过气来的鸟：空气饥饿会影响屠宰时家禽的福利吗？

• 批准号: BB/X000680/1
• 负责人: Jessica Martin
• 金额: $ 72.55万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX000680%2F1
• 关键词: Breathless; Birds; Does; air; hunger

Globally, 72 billion chickens are slaughtered each year. Controlled atmosphere stunning (CAS) is increasingly used, involving exposure to gas mixtures causing gradual loss of consciousness, with welfare advantages compared to electrical stunning. Commercial CAS systems most commonly expose conscious birds to increasing concentrations of carbon dioxide (CO2). Although painful levels of CO2 are avoided, these gases cause a hyperventilation (deep breathing) response which is obvious behaviourally. It unknown whether this reaction corresponds to the breathlessness and 'air hunger' reported by humans when inhaling CO2. Air hunger is a potent and deeply unpleasant experience, consisting of an uncomfortable urge to breathe which is associated with profound anxiety, frustration and fear. If the gas mixtures used in gas stunning cause air hunger in chickens, this constitutes a very significant welfare issue, calling into question whether CAS is a humane method of pre-slaughter stunning. Given the anatomical and physiological differences between mammals and birds, the susceptibility of birds to air hunger is difficult to predict, and no previous studies have specifically examined animal perceptions of this sensation. Although some earlier studies have demonstrated that chickens avoid CO2 in certain situations, the available research has never specifically addressed the contribution of air hunger to this avoidance and is confounded by the fact that CO2 is painful to inhale above certain concentrations. Simple behavioural approaches (such as allowing birds to leave a space containing CO2) are flawed since CO2 is an anaesthetic that is likely to reduce the ability to express appropriate responses. More sophisticated behavioural approaches such as those allowing birds to display any learned aversion after, not during, exposure to CO2, and a focus on non-painful concentrations are needed to understand whether air hunger is a welfare issue. The aim of this project is to determine whether birds experience air hunger during exposure to gas mixtures relevant to commercial slaughter. Initially, we will expose chickens to a range of relevant gas mixtures which represent different CAS methods, untangling their responses to CO2 and low oxygen levels, both of which cause respiratory changes. We will record detailed behavioural and physiological outcomes to determine the conditions under which hyperventilation occurs and how its apparent character and severity relates to gas types and concentrations. We will then investigate whether hyperventilation occurring during CAS represents a welfare issue by evaluating whether chickens avoid and/or escape areas associated with exposure to relevant gas mixtures. We will also deteremine if any spontaneous behaviour corresponds with learned avoidance behaviour to help us understand which apparent signs of breathlessness may indicate unpleasant respiratory experiences. Finally, we will image parts of the brain to examine whether key regions associated with fear, stress and anxiety are activated by exposure to relevant gas mixtures. Collectively, we expect these experiments to allow a corroborative and robust assessment of the welfare implications of hyperventilation.Tackling the question of whether air hunger is experienced by billions of poultry undergoing CAS is extremely important. The work we propose is ground-breaking and will enable the development of novel methodology to detect air hunger in animals. Whatever the findings, the work will provide valuable information to inform future policy globally. If our studies show that air hunger is not an issue relevant to poultry slaughter, CAS will be proven to be a high welfare method and its uptake will be enhanced. If air hunger is apparent, the results will underpin the development of more humane stunning approaches, ensuring that the current transition away from electrical stunning systems represents genuine welfare improvement.

在全球范围内，每年屠杀720亿只鸡。受控大气令人惊叹（CAS）越来越多地使用，涉及暴露于气体混合物，导致逐渐丧失意识，与电气惊人相比，福利优势。商业CAS系统最常见的是将有意识的鸟类暴露于增加二氧化碳（CO2）的浓度。尽管避免了疼痛的二氧化碳水平，但这些气体会引起过度换气（深呼吸）反应，这在行为上显然是显而易见的。尚不清楚这种反应是否对应于吸入二氧化碳时人类报道的呼吸困难和“空气饥饿”。饥饿是一种有力且深刻令人不愉快的经历，包括呼吸的不舒服的冲动，与深刻的焦虑，沮丧和恐惧有关。如果燃气中使用的燃气混合物令人惊叹地导致鸡的气饥饿，则构成了一个非常重要的福利问题，质疑CAS是否是人道的杀人式杀人式令人惊叹的方法。鉴于哺乳动物和鸟类之间的解剖学和生理差异，很难预测鸟类对气饥饿的敏感性，并且以前没有研究专门研究了动物对这种感觉的看法。尽管一些较早的研究表明，在某些情况下，鸡避免了二氧​​化碳，但可用的研究从未具体解决空气饥饿对这种回避的贡献，并且由于二氧化碳对吸入某些浓度的吸入而痛苦而感到困惑。简单的行为方法（例如允许鸟类离开含有CO2的空间）是有缺陷的，因为CO2是一种麻醉剂，可能会降低表达适当反应的能力。更复杂的行为方法，例如允许鸟类表现出任何学习过的厌恶，而不是在接触二氧化碳之后的厌恶，并且需要关注非pain的浓度，以了解空气饥饿是否是福利问题。该项目的目的是确定鸟类在暴露于与商业屠杀有关的气体混合物中是否经历了空气饥饿。最初，我们将使鸡暴露于一系列相关的气体混合物中，这些气体混合物代表不同的CAS方法，解开其对CO2和低氧水平的反应，这两者都会导致呼吸道变化。我们将记录详细的行为和生理结果，以确定发生过度换气的条件以及其表观特征和严重性与气体类型和浓度如何相关。然后，我们将通过评估与暴露于相关气体混合物相关的鸡肉是否避免和/或逃生区域来调查CAS期间发生的过度换气是否代表了福利问题。如果任何自发行为与学习的回避行为相对应，我们还将恶化，以帮助我们了解哪些明显的呼吸迹象可能表明呼吸体验不愉快。最后，我们将图像大脑的一部分，以检查是否通过暴露于相关气体混合物来激活与恐惧，压力和焦虑相关的关键区域。总体而言，我们期望这些实验可以对高换气的福利含义进行佐证和稳健的评估。涉及一个问题，即是否经过数十亿家禽经历了大量CAS的饥饿是非常重要的。我们提出的工作是开创性的，它将能够开发新的方法论，以检测动物的气饥饿。无论发现什么，工作都将提供有价值的信息，以在全球范围内为未来的政策提供信息。如果我们的研究表明，空气饥饿不是与家禽屠杀相关的问题，则CAS将被证明是一种高福利方法，其吸收将得到增强。如果空气饥饿显而易见，结果将支持更令人惊叹的方法的发展，从而确保当前从电气惊人的系统过渡代表真正的福利改善。