Eating increases oxidative damage in a reptile
Butler, Michael W.; Lutz, T. J.; Fokidis, H. B.; Stahlschmidt, Z. R.
While eating has substantial benefits in terms of both nutrient and
energy acquisition, there are physiological costs associated with
digesting and metabolizing a meal. Frequently, these costs have
been documented in the context of energy expenditure while other
physiological costs have been relatively unexplored. Here, we tested
whether the seemingly innocuous act of eating affects either systemic
pro-oxidant (reactive oxygen metabolite, ROM) levels or antioxidant
capacity of corn snakes (Pantherophis guttatus) by collecting plasma
during absorptive (peak increase in metabolic rate due to digestion of
a meal) and non-absorptive (baseline) states. When individuals were
digesting a meal, therewas a minimal increase in antioxidant capacity
relative to baseline (4%), but a substantial increase in ROMs (nearly
155%), even when controlling for circulating nutrient levels.We report
an oxidative cost of eating that is much greater than that due to long
distance flight or mounting an immune response in other taxa. This
result demonstrates the importance of investigating non-energetic
costs associated with meal processing, and it begs future work to
identify the mechanism(s) driving this increase in ROM levels.
Because energetic costs associated with eating are taxonomically
widespread, identifying the taxonomic breadth of eating-induced
ROM increases may provide insights into the interplay between
oxidative damage and life history theory.
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