Influence of the Number of Animals per Cage on the Anxiety Levels in Mice

This study aimed to evaluate the effect of the number of animals per cage behaviour of anxiety in mice exposed to elevated plus-maze. Thir ty Swiss mice were divided into 2 groups: group 1 (G1) and group 2 (G2) with 10 and 20 animals respectively in each cage. Upon reaching 90 days of age, each animal was submitted to the elevated plus-maze, only once in the period of 5 minutes. The parameters evaluated in both groups were: percentage of the number of entries in open arm (% nBA) and percentage of time spent in open arms (% tBA). The statistical analyis did not yield significant difference between the two groups in regarding %nBA (p = 0.87) nor with respect to tBA% (p = 0.98). Our work concluded that the maintenance of 10 or 20 mice per cage did not cause any significant alteration in the anxiety levels of the animals, thus it suggests being indifferent to maintain 10 or 20 mice per cage.