Consistency of ventilation in IVCs and open cages: Their normoxic atmospheres and its impact on haematological parameters of mice

Oxygen concentration in an Individually Ventilated Caging system (IVCs) was recently found to be slightly lower than optimal for an ideal microenvironment to house laboratory mice. Given the substantial technical differences between IVCs of different designs, which may yield dissimilar intra-cage environmental conditions, it was decided to monitor the microenvironment of an Individually Ventilated Cage (IVC) system and an open cage system and compare the impact on Red Blood Cell (RBC) count and related physiological parameters in C57Bl/6J mice housed in open cages. A small decrease in the intra-cage oxygen level was detected in both cage systems when approaching the cage change procedure (per formed every two weeks). No differences in the haematological parameters were detectable after 6 weeks conditioning of mice in either of the two systems. The IVC microenvironment was shown to be free from any impact on the haematological parameters taken into consideration in this trial when compared to the "open cage" set-up.