Figure 3. Relative gene expression levels (mRNA) for citrate synthase (CS: A), cytochrome c oxidase subunit I (CYC-1; B), β-hydroxyacyl-CoA dehydrogenase (HOAD; C), myosin heavy chain slow isoform (sMyHC; D), pyruvate dehydrogenase E₂ subunit (dLat; E), lactate dehydrogenase (LDH; F) and fast (fMyHC; G) isoform in adult zebrafish exposed to cold temperatures (18°C, T) for 4 weeks and exercise trained for 4 weeks (Ex), compared to 28°C controls (C).

Expression levels were measured by real-time PCR using SYBR green. Results are relative to a randomly selected control sample and normalized to β-actin. n= 5 except for MyHC (n= 3). *Significantly different from controls (P < 0.05). Error bars represent s.e.m.