HCRT and atrial fibrillation: In the fasted state, the mRNA level of orexin was the lowest in the control females and lower than those in control males and AF carp (Figure 4C) (p < 0.05); however, in the fed state, the mRNA level of orexin was the highest in the AF carp and significantly higher than those in control females and control males (p < 0.05).