Radical health: ecological corollaries of body condition, transport stress and season on plasma antioxidant capacity in the European badger

Abstract

In the wild, European badgers, Meles meles, naturally display marked individual and seasonal variation in body condition. To establish whether body condition affects their ability to produce an antioxidant defence when exposed to immunological stress, we tested the plasma antioxidant capacity of eighty-eight wild badgers using analysis of emitted light antioxidant kits, with values expressed as vitamin E analogue (VEA) equivalents. The body condition of subject animals was a key explanatory variable in the extent of the antioxidant responses observed. Naturally emaciated animals in the poorest body condition mounted a significantly lower antioxidant response than that recorded for animals with more body fat. Related to natural cycles in body fat (reflecting feeding success), a significant seasonal effect was also observed, VEA equivalent values being significantly higher in autumn than in summer. In addition, animals were also assigned to one of two experimental regimes: non-transported (n=18), that is, sampling at the site of capture, or sampling immediately after transport (transported n=70). Transport consisted of a ride for <10 min (around 1500 m on average) while caged, on a trailer pulled by an all-terrain quad bike; this was a necessary part of our wider studies of these badgers, but incidentally also providing a standardized stressor. Transportation had a marginal, but non-significant, effect on antioxidant capacity, and sex had no interactive effect on the outcome of the transportation treatment, or on body-condition results. These findings are discussed in the context of seasonal corollaries with foraging ecology, giving particular consideration to changing climatic conditions and species management.