Methods used for assessment of laboratory mouse affective state or welfare: a protocol for a systematic mapping review
Authors: Whittaker Alexandra Louise 
Published: June 2023

Abstract Objective: The objective of this review is to systematically map and collate the available scientific evidence on methods used to assess laboratory mouse welfare, with a focus on those methods that are non-invasive and practical for use in day-to-day welfare assessment. Introduction: The number of mice used globally in biomedical research is significant. Since these animals may experience welfare detriment as a result of this research it is imperative that animal carers and researchers are able to reliably assess welfare in these animals. This is necessary not only for the animals themselves but to promote good quality science, and to assist in maintaining a social licence for research on animals. Whilst there are a range of welfare assessment methods reported for mice in the literature, there has been no collation of methods to understand the nature and frequency of investigation of each, and bring together newer methods of assessment. This systematic mapping review aims to achieve this. Inclusion criteria: This review will focus on primary studies of laboratory mouse welfare or affective states. Criteria for inclusion are that welfare indicators are animal-based, as opposed to input measures where welfare status is inferred. Included measures may be of a behavioural, physiological, immunological, or neurobiological nature. Measures should be relatively non-invasive and should, based on the authors’ opinion, be able to be incorporated into a practical welfare assessment program. Methods that require sample collection and analysis, for example of blood or hair, will also be eligible for inclusion based on the previous consideration around feasibility. Retrospective measures, such as those able to be collected after the animals’ death, are eligible for inclusion. Welfare indicators are not limited to individual measures; population-based measures may be included, for example mortality. Methods that are provoked and that require the performance of a specific test, for example behavioural tests of anxiety will be excluded. The extent of feasibility for incorporation of the measures in day-to-day welfare assessment will be discussed in the review.Methods: An advanced search of MEDLINE via Pubmed, Embase, CAB Abstracts, and Scopus will be conducted to identify full-text, English-only articles. No date restrictions will be placed. Grey literature within these databases will be eligible for inclusion and ProQuest Dissertations and Theses will also be searched Two independent reviewers will retrieve and screen full-text studies for inclusion. Extraction will be limited to nature of the welfare indicator, category of indicator, proposed valence of affect being assessed, and whether indicator is of a spontaneous nature or requires sample processing. Results will be presented visually to show types and nature of indicators, number of studies examining them and any associated conditions around use of indicators for example need for sample processing or being retrospective in nature.