Figure 3.

NR supplementation does not affect energy expenditure in B6N or B6J mice. Energy expenditure was determined by indirect calorimetry in metabolic cages. The time course of the energy expenditure measurement is shown in (A) chow-fed B6N, (B) chow-fed B6J, (C) HFD-fed B6N, (D) HFD-fed B6J. Differences were tested by multiple t-tests with Holm–Sidak correction. Differences in average energy expenditure between chow-fed and HFD-fed B6N and B6J mice are shown for (E) the active phase/night and (F) the resting phase/day, body weights at the start of indirect calorimetry assessment are shown in (G) (n = 4 for chow, n = 7 for B6N HFD, n = 10 for B6N HFD+NR, B6J HFD and HFD+NR). The relationship between average nightly energy expenditure and body weight is depicted for B6J and B6N mice when chow-fed (H) and (I) HFD (n = 8 for chow, n = 17 for B6N HFD, n = 20 for B6J HFD). Data are presented as mean ± s.e.m. Tests for statistical significance were done using ordinary two-way ANOVA with diet and mouse strain as factors followed by Tukey’s test for multiple comparisons. Data for NR vs no NR supplementation were analyzed together since no significant differences were found for NR vs no NR. ⁺P  < 0.05 for HFD vs chow, ^*P  < 0.05 for B6J vs B6N Linear regression and analysis of covariance (ANCOVA) was done between average nightly energy expenditure and body weight. Slopes of HFD-fed mice were significantly different (P  < 0.05).