Home Cage Compared with Induction Chamber for Euthanasia of Laboratory Rats

This study compared behavioral and physiologic changes in Sprague-Dawley and Brown Norway rats that were euthanized by using a 30% volume displacement rate of CO2 in either their home cage or an induction chamber; rats euthanized in the home cage were hypothesized to demonstrate a higher level of animal wellbeing. No significant differences were detected in the physiologic responses to home cage versus induction chamber euthanasia groups. A few strain-related behavioral differences occurred. The number of digs per second was higher in Brown Norway compared with Sprague-Dawley rats when in the home cage, where a digging substrate was present. Rearing frequency was higher in both Brown Norway and Sprague-Dawley rats in the induction chamber compared with the home cage. This study demonstrated that although strain-specific differences were associated with the process of euthanasia, there were no significant differences between the treatment groups of home cage compared with induction chamber. This finding suggests that-from the perspective of a rat-either the home cage or an induction chamber can be used for euthanasia, with likely extension of this conclusion to use of either method to the induction of anesthesia.