Effects of housing density on C57BL/6J mice housed in three cage types (2003)

Mabus, S., Smith, E., Basso, C. et al.

Abstract

This 8-week study was initiated to investigate the impact of floor space on the health and well being of C57BL/6J (B6) mice, a strain commonly used by the scientific community. Male and female 4-week-old mice (sexes housed separately) were maintained in duplex boxes (51.7 in2), weaning cages (112.9 in2), or showebox-type cages (67.6 in2). By manipulating the numbers of mice per cage, we housed them at the density recommended in the Guide (12 in2 per mouse) and at three higher densities .... up to 5.7 in2 per mouse...Ammonia levels did not exceed 70 ppm and significantly elevated levels were found only in weaning cages at the thrid highest density. ... Temperatures were higher in boxes holding the two highest densities in all cages. .. Weight gains were not affected by housing density. .. We recommend that B6 male and female mice be housed at densities higher [sic] than thoserecommended in the Guide, up to 8.6 in2 per mouse, irrespective of cage type.