Welfare phenotyping of genetically-modified mice

Technologies that enable the targeted manipulation of the genome have created new opportunities to study the role and interplay of specific genes in both the regulation and function of physiological and behavioural processes and in the development of pathological conditions. Despite the potential benefits, there are ethical issues in relation to the application of these technologies, some of which relate to the impact on the welfare of the animals involved. Matters of concern include the methods involved in the derivation and production of genetically-modified (GM) animals and resulting phenotypes, where animal welfare is compromised. In the case of the latter, this may be the predicted consequence of the genetic modification, but the occurrence of unforeseen animal welfare complications is a major challenge in the management of GM animals. There has been a rapid escalation in the development of new GM lines, most of them involving mice. Databases of available lines have been developed by national and international consortia, and researchers have developed standard protocols to describe the phenotype of a new line; increasingly, such data are entered into these databases. The inclusion of animal welfare assessments with these data would provide a powerful and sophisticated tool to promote refinement. The scope, level and frequency of monitoring would facilitate the identification of unpredicted effects and the management of humane endpoints, and would identify opportunities to manage the animals so as to ameliorate negative impacts. Furthermore, by highlighting the subtleties of gene-environment interactions, such data have wider implications in achieving the goals of refinement.