Micro enviroment of Reusable and Disposable Mouse Cages
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Transcript of Micro enviroment of Reusable and Disposable Mouse Cages
Ammonia and carbon dioxide concentrations in disposable and
reusable static mouse cagesJerald Silverman, DVM, MPS, DACLAM, David W. Bays, BS, LATG & Stephen P. Baker, MScPH
The performance of static mouse cages depends upon the cage's ability to dissipate carbon dioxide and ammonia.
Reusable and disposable cages
Reusable Cage
Gas Sampling Ports
Disposable Cage
Gas sampling ports
Inside view of a gas Sampling port with protective
cover.
Cage location on rack
Dispose
Dispose
Reuse
Reuse
Reuse
Dispose
CD-1™ MouseCrl:CD1(ICR)
Retired breeder females with averageweights of 47 to 48 grams.
Drager CMS Analyzer
Ammonia (ppm)0.2 – 5.0 2.0 – 50 10 – 150
100 – 2,000
Carbon dioxide (ppm)200- 3,000
1000 – 25,000
Intra-cage Temperature & Humidity
Typical placement of data logger
Room Temperature & Humidity
Mean Intracage Temperature &
Relative Humidity
Mean low (oC)
Mean high (oC)
Temperaturerange (oC)
Mean low RH (%)
Mean high RH (%)
RH range (%)
Study period 1 Disposable 21.8 23.8 21.3-24.0 48.6 83.1 45.1-85.2 Reusable 22.4 24.8 21.9-25.2 43.9 86.0 35.7-87.2Study period 2 Disposable 22.5 23.8 21.9-25.2 48.4 83.1 38.3-87.2 Reusable 21.8 24.5 21.0-24.8 57.9 84.2 54.0-87.2
ConclusionsNeither cage type was particularly effective in controlling what empirically is considered to be high levels of ammonia and CO2. Nevertheless, without a clear understanding of the potential adverse health effects of given levels of intracage ammonia and CO2 on laboratory animals and without a consensus on maximal desirable intracage levels of these gases, only estimates can be made about the recommended frequency of cage changing. We suggest, based only on human exposure guidelines and a conservative reading of the available veterinary literature, that intracage levels of 50 ppm of ammonia should lead to cage changing. In the current study that would translate to approximately twice weekly cage changing. The CO2 levels rose so quickly and the effects of CO2 on laboratory animals are so varied that it is quite difficult to recommend any cage changing frequency that is based on CO2 level alone.