Conventional husbandry and the welfare of laboratory mice: assessing and alleviating negative emotions, pessimistic moods, and cumulative stress

点击翻译按钮获取中文摘要

This stage of my program will investigate how positive animal welfare promotes resilience and a long, healthy life. My vision is a comprehensive understanding of how positive and negative events affect stress reactivity, behavioural normalcy and physical health: one that transforms how we assess and improve farm, laboratory and zoo animal housing. For billions of animals globally, housing comprises small enclosures that are cost-effective, yet provide little opportunity for activity or stimulation. But -- as pandemic lockdowns so revealed -- such restrictions can have a cost, in terms of stress and mental health. For example mice, the most widely used vertebrate in biomedical research, are highly motivated to perform many natural behaviours impossible in conventional laboratory `shoebox' cages, even pushing weights heavier than themselves to access cages `enriched' with resources allowing such activities. Furthermore, compared to those living in highly enriched enclosures, female mice in conventional housing are aggressive to their cagemates, 'pessimistic' in cognitive tasks for Judgement Bias, more reactive to acute stressors, prone to abnormal behaviours like repetitive stereotypic route-tracing, and shorter lived. Enriched housing thus does not just reduce frustration: it increases positive social interactions, stress-resilience and lifespan. To inspire practical change, I will therefore use mice, both as a model and worthy target for welfare-enhancing research, to investigate whether barren housing systems make animals depressed; what goes wrong within the brain to generate stereotypic behaviours; what the best ways are to enrich housing; how enriched housing can enhance stress resilience; and why contentment promotes a long, healthy life. To do this, a series of experiments and data meta-analyses will culminate in a uniquely ambitious birth-to-senescence study to assess the lifetime cumulative effects of high/low husbandry stress. This work will test fundamental hypotheses about how emotional states influence moods; how moods affect stress resilience; and the cumulative effects of lifelong moods and resilience on physical and mental health. It will generate practical recommendations for improved husbandry of research mice, and suggest creative new ways to reduce the harms of invasive, painful research procedures. This could generate world-leading lab animal care standards for Canada; and improve well-being for 10s of millions of research rodents used globally p.a (maybe even improving the validity of their research data). Since mice are great models for welfare issues in other species, its findings will also benefit hundreds of applied ethologists, welfare scientists and veterinarians striving to assess and improve welfare in other managed species, by solving some decades old welfare puzzles (such as the aetiology of stereotypic behaviour) and by quantifying the cumulative mental and physical health impacts of good/poor housing.