Behavioural consequences of IVC cages on male and female C57BL/6J mice.

Recent developments in the technology to breed and house laboratory rodents for medical research has produced individually ventilated cage (IVC) systems. These IVC systems produce a cage environment significantly different to conventional cages. As it is not known in detail whether housing mice in IVCs impacts on their baseline and drug-induced behaviours compared to mice of conventional filter-top cages a comprehensive multi-tiered phenotyping strategy was used to test the behavioural consequences of IVC housing in male and female C57BL/6JArc mice. IVC had anxiety-like effects in the elevated plus maze, which were more pronounced in female mice whereas cognition and locomotion of all test mice were not modified by IVC housing. Mice raised in IVC cage systems were socially more active than mice of filter-top systems. Furthermore, males raised in IVC exhibited an increased sensitivity to the locomotor-stimulating effects of acute MK-801 treatment compared to males in conventional cages. In summary, this is the first study revealing the longer-term effects of IVC housing on social behaviours and the locomotor response to an acute MK-801 challenge. In conclusion, researchers upgrading their holding facilities to IVC housing may encounter a shift in experimental outcomes (e.g. post pharmacological challenges) and the behavioural phenotype of test mice. Furthermore, differences between the housing conditions of breeding facilities and test facilities must carefully be considered. Finally, researchers should clarify in detail the type of housing test animals have been exposed to when publishing experimental animal research data.