Table 1.
Characteristics of fed and fasted rats.
| State | Fed | P2 | P3 |
|---|---|---|---|
| Main Fuels | Mix * | Lipids | Proteins |
| Rat profiles | |||
| Duration of fasting (days) | - | 5.6 ± 0.4 | 7.8 ± 0.5 ◊ |
| Initial body mass (g) | 344.5 ± 1.6 | 347.7 ± 2.2 | 346.4 ± 2.4 |
| Final body mass (g) | 344.5 ± 1.6 | 268.5 ± 1.7 # | 225.0 ± 2.0 # ◊ |
| Body mass loss (%) | - | 22.7 ± 0.4 | 35.0 ± 0.3 ◊ |
| dm/m.dt (g.100−1.d−1) | - | 3.7 ± 0.3 | 7.6 ± 0.3 ◊ |
| VO2 (mL O2.min−1.(kg0.67)−1) | 18.95 ± 0.02 | 14.82 ± 0.7 # | 14.44 ± 0.8 # |
| Respiratory quotient (RQ) | 0.92 ± 0.01 | 0.69 ± 0.01 | 0.75 ± 0.01 |
| Plasma | |||
| NEFA (mM) | 0.57 ± 0.04 | 0.78 ± 0.03 # | 0.19 ± 0.02 # ◊ |
| Urea (mg.dL−1) | 21.4 ± 1.1 | 16.0 ± 1.1 | 44.4 ± 3.1 # ◊ |
| Glucose (mM) | 8.0 ± 0.3 | 6.2 ± 0.1 # | 5.5 ± 0.3 # |
| Muscles | |||
| TIB mass (mg) | 1220.0 ± 47.3 | 1100.0 ± 20.7 | 962.0 ± 35.4 # ◊ |
| SOL mass (mg) | 330.0 ± 24.5 | 282.0 ± 13.6 | 280.0 ± 12.2 |
| Heart mass (mg) | 1479.3 ± 70.7 | 1405.7 ± 41.6 | 1025.1 ± 47.5 # ◊ |
Values are the means ± standard error of the mean (SEM) (N = 5/group). VO2 and the respiratory quotient (RQ) values are those obtained the day of the sacrifice. P2 and P3: phase 2 and phase 3 of fasting; TIB: tibialis anterior muscle; SOL: soleus muscle; NEFA: non-esterified fatty acids. * Main fuels include carbohydrates, lipids and proteins; # p-value < 0.05 vs. fed, ◊ p-value < 0.05 vs. P2 (one-way ANOVA, Tukey tests, and Welch two sample t-tests).