Linear Mixed Effects Models
Linear mixed effects models including bird identification number and
cohort number as random factors were used to analyze the longitudinal
plasma data to test the hypotheses (H1a) that acute flight decreases
oxidative capacity during flight and enables oxidative damage levels to
remain low, and (H1b) that regularly flying increases antioxidant
capacity and oxidative damage. Linear mixed models that controlled for
experimental cohort as a random factor were also used to test the
hypothesis that flight-training (H1c), dietary fat (H2), and dietary
antioxidants (H3) influenced Δ during training of plasma lipid damage
and lipid damage in the liver and pectoralis. We conducted pairwise
comparisons using least square means to determine the differences in
oxidative status between specific timepoints.