Stimulatory effect of flight training across time: Acute-effect of a long flight (H1a)
Regular bouts of acute flight influenced OXY and d-ROMs in the plasma of flight-trained birds (i.e., comparison of BG, PF, AF, and RC blood samples; Fig. 1). Plasma d-ROMs was highest after two weeks of daily flight training compared to all other timepoints (Fig. 2; BG vs PF: T49 = -3.042, P = 0.0027, PF vs RC: T49= 3.085, P = 0.0023). Immediately after an on average 193 +/-71 min flight the next day, plasma d-ROMs had substantially decreased relative to PF (Fig. 2A, Table S1; PF vs AF: T49 = 3.85, P = 0.0002). In contrast, plasma OXY after two weeks of daily flight (PF) was substantially lower than BG and recovery levels two days later (Fig. 2B, Table S1; BG vs PF: T49 = 6.058, P < 0.0001, PF vs RC: T49 = -6.113, P < 0.0001). Similar to d-ROMs, immediately after a long-duration flight the next day, plasma OXY further decreased relative to PF (Fig. 2B, Table S1; PF vs AF: T49 = 2.330, P = 0.021), and then returned to baseline levels at RC (BG vs AF: T49 = 8.993, P < 0.0001, AF vs RC: T49 = -8.544, P < 0.0001, BG vs RC: T49 = 0.0694, P since plasma antioxidant capacity decreased during a given long-duration flight and levels of circulating oxidative damage remained lower than or at baseline levels.