Cage change intervals for opossums (Monodelphis domestica) in individually ventilated cages.

The opossum Monodelphis domestica is the most commonly used marsupial in biomedical research. At our institution, these opossums are housed in polycarbonate (35.6 cm × 25.4 cm × 17.8 cm) individually ventilated cages. Previous studies of the cage microenvironment of rodents housed in individually ventilated cages have demonstrated that the cage-change frequency could be extended from 7 to 14 d, without detriment to the animals' wellbeing. We sought to determine whether the cage change frequency for opossums housed in individually ventilated cages could be extended to 14 d. Opossums were placed into 3 experimental groups: singly housed males, singly housed females, and females housed with litters. The 14-d testing period was repeated twice, with temperature, relative humidity, and ammonia levels tested on days 0, 7, and 14. Acceptable ranges for the cage microenvironment were based on standards followed by our institution for housing rodents: temperature between 22 to 26 °C, relative humidity between 30% to 70%, and ammonia less than 25 ppm. Throughout both 14-d testing periods, temperature, relative humidity, and ammonia levels for singly housed male and singly housed female opossums were within acceptable ranges. However, ammonia levels exceeded the recommended 25 ppm on day 7 of both testing periods for female opossums housed with litters. In summary, the cage-change frequency for a singly housed opossum in an individually ventilated cage can be extended to 14 d.

[1]  S. Vandewoude,et al.  Effects of cage-change frequency and bedding volume on mice and their microenvironment. , 2009, Journal of the American Association for Laboratory Animal Science : JAALAS.

[2]  J. Silverman,et al.  Ammonia and carbon dioxide concentrations in disposable and reusable static mouse cages , 2009, Lab Animal.

[3]  J. Silverman,et al.  Ammonia and carbon dioxide concentrations in disposable and reusable ventilated mouse cages. , 2008, Journal of the American Association for Laboratory Animal Science : JAALAS.

[4]  P. Harrison,et al.  Mass Generation Rates of Ammonia, Moisture, and Heat Production in Mouse Cages with Two Bedding Types, Two Mouse Strains, and Two Room Relative Humidities , 2006 .

[5]  F. Memarzadeh,et al.  Control of ammonia production in animal research facilities through ventilation system design , 2005 .

[6]  J. Stockwell,et al.  Evaluation of cage micro-environment of mice housed on various types of bedding materials. , 2004, Contemporary topics in laboratory animal science.

[7]  P. Harrison,et al.  Comparison of environment and mice in static and mechanically ventilated isolator cages with different air velocities and ventilation designs. , 2004, Contemporary topics in laboratory animal science.

[8]  S. Pathak,et al.  In vivo opossum xenograft model for cancer research. , 2003, Cancer research.

[9]  A. K. Hansen,et al.  The impact of low levels of carbon dioxide on rats , 2003, Laboratory animals.

[10]  A. K. Hansen,et al.  The impact of cage ventilation on rats housed in IVC systems , 2003, Laboratory animals.

[11]  V. Baumans,et al.  Individually ventilated cages: beneficial for mice and men? , 2002, Contemporary topics in laboratory animal science.

[12]  G. Churchill,et al.  The impact of reduced frequency of cage changes on the health of mice housed in ventilated cages , 2001, Laboratory animals.

[13]  A. Renström,et al.  Evaluation of individually ventilated cage systems for laboratory rodents: cage environment and animal health aspects , 2001, Laboratory animals.

[14]  Robert B. Jones,et al.  Microenvironment in Ventilated Animal Cages with Differing Ventilation Rates, Mice Populations, and Frequency of Bedding Changes. , 1998, Contemporary topics in laboratory animal science.

[15]  J. VandeBerg,et al.  The Laboratory Opossum (Monodelphis Domestica) in Laboratory Research. , 1997, ILAR journal.

[16]  Robert B. Jones,et al.  Impact of Room Ventilation Rates on Mouse Cage Ventilation and Microenvironment. , 1997, Contemporary topics in laboratory animal science.

[17]  B. Paigen,et al.  Air quality in an animal facility: particulates, ammonia, and volatile organic compounds. , 1996, American Industrial Hygiene Association journal.

[18]  N. Lipman,et al.  Characterization and quantification of microenvironmental contaminants in isolator cages with a variety of contact beddings. , 1995, Contemporary topics in laboratory animal science.

[19]  J. Eveleigh.  Murine cage density: cage ammonia levels during the reproductive performance of an inbred strain and two outbred stocks of monogamous breeding pairs of mice , 1993, Laboratory animals.

[20]  B. Fadem,et al.  Reproduction, development and physiology of the gray short-tailed opossum (Monodelphis domestica). , 1987, Laboratory animal science.

[21]  T. Schoeb,et al.  Intracage ammonia promotes growth of Mycoplasma pulmonis in the respiratory tract of rats , 1982, Infection and immunity.

[22]  B. Fadem,et al.  Care and breeding of the gray, short-tailed opossum (Monodelphis domestica) , 1982, Laboratory animal science.

[23]  J. Lindsey,et al.  The role of environmental ammonia in respiratory mycoplasmosis of rats. , 1976, The American journal of pathology.