Forty mouse strain survey of body composition

We measured body weight and composition of ∼ 10 male and ∼ 10 female mice from 40 inbred strains. Body composition was assessed in ∼ 16-wk old mice that had been individually housed and fed a high-carbohydrate, low-fat diet (AIN-76A) for the previous 8 wk. Carcass lean and fat weights were assessed using a PIXIMus II DEXA and confirmed by fat extraction assay. There was a nearly continuous range of body weights, from a strain mean ± SE of 11.4 ± 0.2 g (MSM/MsJ) to 39.3 ± 1.8 g (NON/LtJ). The percentage of body weight that was fat (%Fat) ranged from 16 ± 4% (C58/J) to 39 ± 2% (NON/LtJ). In general, heavier strains had a higher %Fat (r = 0.57) but several light strains were also quite fat (e.g., SPRET/EiJ, body weight = 15.7 ± 0.6 g, %Fat = 26 ± 1%). Males were significantly heavier than females in 26 strains and significantly fatter than females in 9 strains; only the KK/H1J strain had fatter females than males. Some of the fattest strains are infrequently used in obesity experiments, for example the JF1/Ms and CBA/J strains. These data illustrate the diversity of body weight and composition in inbred mice. They will serve as a reference standard and assist in the selection of strains for future work.