Ageing and reproduction: antioxidant supplementation alleviates telomere loss in wild birds

Abstract

Reproduction is inherently costly. Environmental stressors, such as infection and limited food resources, can compromise investment at each breeding attempt. For example, recent data on captive birds showed that increased reproductive effort accelerates ageing. However, the effects of nutritional status and infection on ageing remain unknown. Telomeres function as protective caps at the ends of eukaryotic chromosomes, and changes in telomere length is a commonly used proxy for ageing. To partially address the mechanisms of ageing following reproduction, we supplemented, medicated or administered a combined treatment to wild blue tits (Cyanistes caeruleus) breeding in central Spain during 2012. The nutritional supplement consisted of two different antioxidants, whereas the medication was an antimalarial treatment against blood parasites. We evaluated the effect of these manipulations on reproductive success and parasite loads in the first breeding season, and on changes in telomere length between two consecutive breeding seasons. Supplemented birds showed no reduction in blood parasite infections in 2012, although they exhibited higher body mass and fledging success. The antimalarial drugs reduced infections by several parasite species, but this had no effect on fitness parameters. In the following season, telomeres from supplemented birds had shortened less. Altogether, we found that supplementation with antioxidants provided fitness benefits in the short term and reduced telomere loss a year following treatment. Our results provide indirect empirical support for accelerated telomere loss as a cost of reproduction.

Individual Quality and Extra‐Pair Paternity in the Blue Tit: Sexy Males Bear the Costs

“…Although extra‐pair copulations occur before the nestling provisioning phase and therefore are unlikely to be affected by an experimental treatment to adult birds during this phase, we confirmed that the experiments in 2012 (Badás et al. ) and 2013 (unpubl. data) were not related to extra‐pair paternity (2012: χ 2 3 = 2.64, P ‐value = 0.45, N = 78; 2013: χ 2 2 = 2.29, P ‐value = 0.32, N = 63).…”

“…In season 1, reproductive success could not be evaluated because this was affected by an experimental treatment (Badás et al. ). For each season and response variable, to avoid multicollinearity or sample size problems when a large number of explanatory variables are evaluated, we designed partial least squares regression models (PLSR; Carrascal et al.…”

Yolk vitamin E prevents oxidative damage in gull hatchlings

“…These results combined suggest that availability of egg maternal and dietary VE has little influence on telomere dynamics in early life stages. However, such effects may become apparent at a later life stage, as shown for blue tit nestlings where the positive effect of a one-shot treatment with VE and methionine via subcutaneous injection on TL could be recorded 1 year after treatment [24]. …”

Harsh conditions during early development influence telomere length in an altricial passerine: Links with oxidative stress and corticosteroids

“…Some previous studies have examined the effects of within‐brood competition on telomere shortening (Boonekamp et al., ; Nettle et al., ; Reichert et al., ; Voillemot et al., ) or the role of oxidative stress on telomere dynamics by manipulating antioxidants (Badás et al., ; Kim & Velando, ; Noguera, Metcalfe, Boner, & Monaghan, ) or corticosterone (Haussmann, Longenecker, Marchetto, Juliano, & Bowden, ) during development. In this study, we experimentally manipulated developmental stress by means of a brood size manipulation to assess its effect in telomere length in a wild passerine, the spotless starling, Sturnus unicolor .…”