There were significant interactions between hypothyroid treatment and acclimation temperature for liver transcript levels of PGC1β, PPARδ, NRF1, NRF2a, NRF2b, COX VB2, COX II, and ATPase 8/6, whereby hypothyroidism significantly increased the transcript levels of PGC1β, PPARδ, NRF1, NRF2a, and NRF2b in cold-acclimated fish and significantly reduced transcript levels of PGC1β and COX II in warm-acclimated fish (Figure 3D; Table 5; see Additional file 1: Table S1). This evidence concerns the gene PPARD and hypothyroidism.