[The effect of cage type and population density on the body weight development of laboratory mice]

The effect of different keeping conditions on body weight gain was studied in 200 male Fzt:DU mice between days 21 and 70 of life. The animals were divided in four different housing groups: DU-B (housing in stress cages), DU-B+HI (housing in stress cages and afterwards in standard cages type HI), DU-HI (housing in standard cages type HI) and DU-S+AP (housing in standard group cages). Housing in stress cages resulted in lower body weight gain at every age; subsequent housing in standard cages type HI for one week failed to compensate this effects. Likewise, keeping of four mice in standard cages type I (DU-HI) between days 42 and 70 of life also resulted in delayed body weight gain. It is possible that the chosen population density was not an optimum for normal weight gain during the adult life. Animals kept in standard stocking cages (DU-S+AP) had the highest body weight gain.