Comparison of three IVC systems for mice, with focus on growth and nest building in juvenile mice
Today the individual ventilated cage system (IVC-system) is the most commonly used system when housing rodents. IVC systems are designed to control both supply and exhausted air at cage level, as well as temperature and relative humidity in the cages. This creates an optimal environment for the mouse and at the same time a protection against the risk of cross-infection between cages and the outside environment. The aim of this study was to evaluate the health and welfare for two different strains of laboratory mice (NMRI nude mice and C57BL/6NCrl mice) in three different kinds of IVC-systems; Arrowmight, Allentown and Tecniplast. 108 mouse pups from each strain (in total 216 mice) were selected after weaning at an age of three weeks and tested during 5 weeks. Behavioural direct observations were made in their home cages with focus on aggressive and abnormal behavior e.g. stereotypic behavior such as gnawing on bar or jumping on cage walls trying to get out. Place and shape of nest were observed. The nest was also scored. Measurements of water and food intake and weight gain were taken. The results show differences in nest quality with a higher score for NMRI nude mice in Arrowmight system meanwhile C57BL/6NClr mice in Allentown and Arrowmight system had highest scores and Tecniplast lowest. The results also showed a higher body weight gain for NMRI nude mice in Arrowmight system and lowest in Allentown system. But neither food nor water intake showed any difference between the three systems. Although differences were found in this study, it is still not enough to exclude or favor for a specific IVC system. But together with recordings of other relevant parameters, based on animal welfare, they could have substantial influence on the choice of IVC system. The more results that can be collected from different parameters, the more improved the choice of IVC system can be. Other relevant parameters to study could be the effect of technical aids when handling animals as well as cages at e.g. cage cleaning, or what type of sound and light the animals are exposed to in the cages since they for example can hear ultrasounds. Further, the appropriate group size in IVC cages and what type of enrichment item to use are also important aspects to consider since the mice naturally live in groups in a varying environment.