Fig. 2.

Nocturnal respiratory exchange ration (RER) in founder and pre-CC lines prior to exercise. RER (V̇co₂/V̇o₂), a measure of energy utilization, was far more variable in pre-CC lines than in founders. RER values of 0.7 ad 1.0 represent using pure fat or carbohydrate, respectively, as energy. Mixed diets tend to produce RER values between 0.8 and 0.9. Extreme values beyond 1.0 may indicate hyperactivity, anxiety, or stress. Several pre-CC lines demonstrated extreme low or high RER vs. founder lines. Group means for each founder line are indicated in black with appropriate color-coded asterisk above to indicate strain being depicted.