An assessment of the welfare of non-human primates used in neuroscience research

Thesis

The Animals (Scientific Procedures) Act 1986 governs the use of animals in scientific research in the UK. Embedded within this is a requirement to implement the 3Rs: replacement, reduction, and refinement; a key mechanism for minimising the pain, suffering, distress, and lasting harm of research models. To adhere fully to these principles, it is imperative to assess animal welfare. Non-human primates (NHP) human similarities make them both an essential biomedical research model and a species particularly vulnerable to welfare challenges. This thesis investigates non-invasive, objective methods of welfare assessment and applies them alongside neuroscience research to monitor the welfare of rhesus macaques (Macaca mulatta).

Accelerometers monitored changes in activity levels following general anaesthesia (GA) and revealed a decline in activity for 5.7 days following GA alone. Additionally, 2.6 days of activity decline were observed after surgery under GA, followed by an activity increase, suggesting post-operative behavioural change. Additionally, accelerometers were used to create a rule-based model for automated behavioural assessment. This model groups macaque activity into 5 species-typical behavioural categories with an overall 69% accuracy.

Physiological welfare parameters were assessed by detecting cortisol in faeces and hair. Faecal cortisol levels were significantly elevated for several days following GA, with a longer and more profound increase after surgery. Hair samples are a valuable measure of chronic stress and cumulative experience, facilitating longitudinal cortisol assessment without influence from transient stressors. Hair cortisol levels were significantly elevated post-surgery and, in some cases, following social disruption.

A customised, neck-based ECG was designed to monitor heart rate variability. The ECG was trialled on anaesthetised and restrained NHPs, dogs, and sheep. Proof of concept was achieved, with R-waves detectable in all species.

Overall, this thesis demonstrates how welfare and neuroscience research can be conducted in parallel for a better understanding of the life-time experience of animal models. This is an essential step towards implementing refinements and improving welfare, which may ultimately improve public perception and help to form the evidence-base required to inform and drive policy change.

Authors: Heppenstall, R

• DOI: 10.5287/ora-jx5qpjpa6
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: non-human primate; accelerometer; stress; animal welfare; ECG; 3Rs; neuroscience; macaque; general anaesthesia; cortisol; behaviour
• Subjects: Macaques--Behavior; Rhesus monkey; Stress (Physiology); Animal welfare