Embryonic exposure to corticosterone modifies the juvenile stress response, oxidative stress and telomere length

Abstract

Early embryonic exposure to maternal glucocorticoids can broadly impact physiology and behaviour across phylogenetically diverse taxa. The transfer of maternal glucocorticoids to offspring may be an inevitable cost associated with poor environmental conditions, or serve as a maternal effect that alters offspring phenotype in preparation for a stressful environment. Regardless, maternal glucocorticoids are likely to have both costs and benefits that are paid and collected over different developmental time periods. We manipulated yolk corticosterone (cort) in domestic chickens (Gallus domesticus) to examine the potential impacts of embryonic exposure to maternal stress on the juvenile stress response and cellular ageing. Here, we report that juveniles exposed to experimentally increased cort in ovo had a protracted decline in cort during the recovery phase of the stress response. All birds, regardless of treatment group, shifted to oxidative stress during an acute stress response. In addition, embryonic exposure to cort resulted in higher levels of reactive oxygen metabolites and an over-representation of short telomeres compared with the control birds. In many species, individuals with higher levels of oxidative stress and shorter telomeres have the poorest survival prospects. Given this, long-term costs of glucocorticoid-induced phenotypes may include accelerated ageing and increased mortality.

Family-transmitted stress in a wild bird

“…These oxidative costs support the general view of glucocorticoid hormones as modulators of oxidative status in vertebrates (22). In birds, prenatal elevation of corticosterone levels is associated with postnatal oxidative costs (40), agreeing with our result of the longterm effect of early exposure to corticosterone on oxidative damage. Importantly, high levels of oxidative damage at fledging are related to a reduction in adult survival in seabirds (41,42).…”

Heritability of telomere length in the Zebra Finch

“…Most phenotyped offspring were cross-fostered at a young age, but cross-fostering of chicks does not control for parental effects arising during laying, incubation and in the few days after hatching that they spent in their natal nest. Pre-natal environmental effects on telomere length can, for example, include endocrinology aspects of egg composition (Haussmann et al 2012), and we cannot exclude that such effects increased the resemblance between (half-)siblings in our study. On the other hand, the mother primarily determines egg characteristics, and effects of father and mother identity on offspring telomere length were indistinguishable in our study (Table 5, model 4).…”

Socioecological variables predict telomere length in wild spotted hyenas

“…Hyenas from high-ranking matrilines might be born with longer telomeres than those from low-ranking matrilines, but we could not test this, nor did we find any evidence that maternal telomere length predicts offspring telomere length (electronic supplementary material, table S3). Increasing evidence shows that pre-and post-natal stress can have long-lasting effects on adult telomere length [3,19,20]. Spotted hyenas experience the highest mortality rates during the period immediately after weaning [21], and this may coincide with a high rate of telomere shortening.…”