Data from: Repeated stressors in adulthood increase the rate of biological ageing

Background: Individuals of the same age can differ substantially in the
degree to which they have accumulated tissue damage, akin to bodily wear
and tear, from past experiences. This accumulated tissue damage reflects
the individual’s biological age and may better predict physiological and
behavioural performance than the individual‘s chronological age. However,
at present it remains unclear how to reliably assess biological age in
individual wild vertebrates. Methods: We exposed hand-raised adult
Eurasian blackbirds (Turdus merula) to a combination of repeated immune
and disturbance stressors for over one year to determine the effects of
chronic stress on potential biomarkers of biological ageing including
telomere shortening, oxidative stress load, and glucocorticoid hormones.
We also assessed general measures of individual condition including body
mass and locomotor activity. Results: By the end of the experiment,
stress-exposed birds showed greater decreases in telomere lengths.
Stress-exposed birds also maintained higher circulating levels of
oxidative damage compared with control birds. Other potential biomarkers
such as concentrations of antioxidants and glucocorticoid hormone traits
showed greater resilience and did not differ significantly between
treatment groups. Conclusions: The current data demonstrate that repeated
exposure to experimental stressors affects the rate of biological ageing
in adult Eurasian blackbirds. Both telomeres and oxidative damage were
affected by repeated stress exposure and thus can serve as blood-derived
biomarkers of biological ageing.