PhenoWorld: addressing animal welfare in a new paradigm to house and assess rat behaviour

Abstract

The use of animals is essential in biomedical research. The laboratory environment where the animals are housed has a major impact on them throughout their lives and influences the outcome of animal experiments. Therefore, there has been an increased effort in the refinement of laboratory housing conditions which is explicitly reflected in international regulations and recommendations. Since housing conditions affect behaviour and brain function as well as well-being, the validation of an animal model or paradigm to study the brain and central nervous system disorders is not complete without an evaluation of its implication on animal welfare. Here we discuss several aspects of animal welfare, comparing groups of six rats living in the PhenoWorld (PhW), a recently developed and validated paradigm for studying rodent behaviour, with standard-housed animals (in cages of six rats or pair-housed). In this study we present new data on home-cage behaviour showing that PhW animals have a clearer circadian pattern of sleep and social interaction. We conclude that, by promoting good basic health and functioning, together with the performance of natural behaviours, and maintaining animals' control over some of their environment but still keeping some physical and social challenges, the PhW stimulates positive affective states and higher motivation in rats, which might contribute to an increased welfare for animals living in the PhW.

Major oscillations in spontaneous home-cage activity in C57BL/6 mice housed under constant conditions

“…The aspiration to obtain cumulative records of laboratory animal behaviors in a "non-intrusive home-cage like style" dates back more than a century (for an historical re-collection see 33 ) but was until recently restricted to a limited set of tools like the running wheel integrated in the home cage (served critically for the understanding of the circadian rhythm in small rodents). Over the past few years a number of techniques 3,7,[34][35][36][37][38][39][40][41][42][43][44][45][46] have become available for automated non-intrusive 24/7 monitoring of in-cage activity 47 of single housed 7,35,40,44 and group housed 8,34,36,37,43,45,48,49 small rodents. Recently we analyzed data of cage floor activity of group-held mice using a DVC system to characterize daily rhythms of spontaneous in-cage activity and impact by husbandry routines 8 .…”

New Horizons for Phenotyping Behavior in Rodents: The Example of Depressive-Like Behavior

“…Also, evidence gathered in studies using enriched environments where rodents’ face more challenges than standard rodent housing, in a naturalistic context has the potential to produce more consistent and valid results. Our series of studies on the PhenoWorld (PhW) provide some evidence in this direction ( Castelhano-Carlos et al, 2014 , 2017 ). In a comparison between a PhW colony of rats and rats housed in standard cages (6 rats in both cases) a number of aspects emerged: PhW animals had (i) better circadian sleep/wake rhythms in comparison to standard housed animals; (ii) reduced/increased levels of corticosterone at light/dark phases; and (iii) better performance in helplessness, anhedonia and anxiety paradigms.…”

New Open-Source Tools: Using Bonsai for Behavioral Tracking and Closed-Loop Experiments

“…Leveraging on this exciting open-source hardware/software ecosystem, it is now possible to study animals' naturalistic behaviors while maintaining control over many other variables, and potentially also integrating it with large-scale housing environments (Castelhano-Carlos et al, 2017). In other words, instead of letting existing behavioral paradigms drive the research question, scientists can now design and implement custom behavioral neuroscience experiments with unprecedented control and intellectual freedom.…”