Antioxidants and telomere length are potential biomarkers for
individuals’ exposure and ability to cope with environmental stressors.
However, intraspecific variations in antioxidant alterations due to
natural, life cycle related stress, have been rarely estimated. We
investigated those changes in wild-derived house mice in a longitudinal
study with natural sibling competition as a stressor. Blood was used for
telomere length measurements at 8-weeks age and for several selected
antioxidants at 8-weeks and 6-months age. Our results show that most of
the antioxidants increase during that time, indicating that
antioxidant-system continues to develop after early development and
sexual maturation. In addition females had higher antioxidant-levels
than males. Mice with longer telomeres had also higher superoxide
dismutase-activity and more glutathione than mice with shorter
telomeres, meaning that long telomeres are associated with better
antioxidant defense at maturation and during later life. Sibling
competition at early age affected superoxide dismutase-levels at
6-months, but only in females. Females, which were lighter than the
average of the litter had low superoxide dismutase –activity in later
adulthood, indicating delayed negative effect of sibling competition on
antioxidant defense. Our results highlight that sex and developmental
stage are crucial in intraspecific comparisons of the antioxidant status
and its alterations.