Abstract
There is a growing body of evidence that enrichment of the housing conditions of laboratory animals has positive effects on daily behavior, growth, and health. Laboratory mice spend most of their lives in their housing rather than in experimental apparatus, so improving housing conditions is a first-choice approach to improving their welfare. Despite the increasing popularity of enrichment, little is known about whether it is also perceived as being beneficial from the animal’s point of view. This is especially true due to the fact that ‘enrichment’ has become an umbrella term that encompasses a wide variety of different elements. We categorized enrichment items according to their prospective use into the categories ‘structural’, ‘housing’, and ‘foraging’ and let female C57BL/6J mice chose within the categories according to their preference. Preferences were tested over a 46-hour period in a home cage system consisting of two interconnected cages equipped with the respective items to be compared. A new analysing method combined binary decisions and ranked the enrichment items within each category by calculating worth values. The assignment of worth values to the items to be compared led to a further gain in information, estimating importance from the mice’s point of view in addition to pure ranking. Given the known beneficial effects of enrichment, these data will help in deciding how to provide appropriate enrichment elements to improve animal welfare and refine animal experimentation.
Competing Interest Statement
The authors have declared no competing interest.