Reproductive effort transiently reduces antioxidant capacity in a wild bird

Oxidative stress has been suggested as a proximate cost of reproduction and hence as a major constraint in the evolution of life histories, and it is therefore thought that antioxidants alleviate the effects of reproductive effort on oxidative stress. Furthermore, carotenoid-based ornaments have been proposed to mirror male ability to resist oxidative stress. Using a full-factorial experimental design in a natural population of great tits Parus major, we manipulated brood size and supplemented the male parent with either carotenoids or a placebo. We then assessed antioxidant capacity via a measure of whole blood resistance to a free radical attack during the nestling rearing period. Males of enlarged broods showed impaired antioxidant capacity 5 days after the brood size manipulation. However, 13 days after manipulation, they had their antioxidant capacity restored, an effect that may be due to the development of compensatory antioxidant mechanisms or due to reduced investment in the current reproduction in favor of future survival and reproduction. Carotenoid supplementation did not affect male antioxidant capacity nor was the interaction with the brood manipulation significant. Males with stronger carotenoid-based plumage colors did not show higher antioxidant capacity 5 days after the brood size manipulation, but after 13 days, the relationship was highly significant. This study on a natural population shows that larger brood size can induce a transient decrease in antioxidant capacity. It also supports the hypothesis that carotenoid-based plumage may signal male ability to resist oxidative stress, particularly during the energetically demanding nestling rearing perio

Effect of sibling competition and male carotenoid supply on offspring condition and oxidative stress

Early developmental conditions have major implications for an individual's fitness. In species where offspring are born simultaneously, the level of sibling competition for food access is intense. In birds, high sibling competition may subject nestlings to decreased growth rate as a result of limited food and increased levels of oxidative stress through high metabolic activity induced by begging behaviors. We manipulated the level of sibling competition in a natural population of great tits and assessed the consequences for nestling body condition and resistance to oxidative stress. In a full factorial design, we both augmented brood size to increase sibling competition and supplemented the male parents with physiological doses of carotenoids thereby doubling the natural carotenoid intake, aiming at increasing the males' investment in current reproduction and thereby decreasing sibling competition. Nestling body mass was reduced by the brood enlargement and enhanced by the carotenoid supplementation of fathers. Nestling resistance to oxidative stress, measured as total antioxidant defenses in whole blood, was not influenced by the treatments. Because nestlings experience high metabolic activities, an absence of an effect of sibling competition on free radicals production seems unlikely. Nestling body mass decreased and resistance to oxidative stress tended to increase with initial brood size, and hence these correlational effects suggest a trade-off between morphological growth and development of the antioxidant system. However, the result of the experimental treatment did not support this trade-off hypothesis. Alternatively, it suggests that nestling developed compensatory mechanisms that were not detected by our antioxidant capacity measur

Females of carotenoid-supplemented males are more faithful and produce higher quality offspring

Reproduction is known to increase the basal metabolic rate and generate oxidative stress, a possible proximate cost of reproduction. Carotenoids have been shown to be in vitro antioxidant molecules and, in a number of instances, to contribute in vivo to the antioxidant protection of the organism against the deleterious effects of free radicals and oxidative stress. These compounds are also involved in the up- and downregulation of the immune system. Thus, carotenoids may improve a male's health status and condition during breeding and enhance his attractiveness through, for example, a higher investment into mating activities. The differential allocation hypothesis predicts that females should invest more in reproduction when mated to more attractive partners. Therefore, a supplementary dose of carotenoids during breeding should increase male attractiveness and translate into higher reproductive success via a higher reproductive effort by their mate. We tested this hypothesis in great tits by supplementing males with carotenoids during their female's fertile period. We subsequently transferred entire clutches into unmanipulated foster nests. Thus, any effect of our carotenoid supplementation to males on their reproductive success must be due to female differential reproductive investment. Offspring sired by carotenoid-supplemented males were found to grow bigger and heavier and to fledge more successfully. Carotenoid-supplemented males also lost less paternity. Our results illustrate the fitness benefits males can accrue from carotenoids and underline the selective pressure imposed on males to optimize carotenoid acquisitio

Quantifying inbreeding avoidance through extra-pair reproduction

© 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.Peer reviewedPublisher PD

Plasma markers of oxidative stress are uncorrelated in a wild mammal.

This is the final version of the article. Available from Wiley via the DOI in this record.Oxidative stress, which results from an imbalance between the production of potentially damaging reactive oxygen species versus antioxidant defenses and repair mechanisms, has been proposed as an important mediator of life-history trade-offs. A plethora of biomarkers associated with oxidative stress exist, but few ecological studies have examined the relationships among different markers in organisms experiencing natural conditions or tested whether those relationships are stable across different environments and demographic groups. It is therefore not clear to what extent studies of different markers can be compared, or whether studies that focus on a single marker can draw general conclusions regarding oxidative stress. We measured widely used markers of oxidative damage (protein carbonyls and malondialdehyde) and antioxidant defense (superoxide dismutase and total antioxidant capacity) from 706 plasma samples collected over a 4-year period in a wild population of Soay sheep on St Kilda. We quantified the correlation structure among these four markers across the entire sample set and also within separate years, age groups (lambs and adults), and sexes. We found some moderately strong correlations between some pairs of markers when data from all 4 years were pooled. However, these correlations were caused by considerable among-year variation in mean marker values; correlation coefficients were small and not significantly different from zero after accounting for among-year variation. Furthermore, within each year, age, and sex subgroup, the pairwise correlation coefficients among the four markers were weak, nonsignificant, and distributed around zero. In addition, principal component analysis confirmed that the four markers represented four independent axes of variation. Our results suggest that plasma markers of oxidative stress may vary dramatically among years, presumably due to environmental conditions, and that this variation can induce population-level correlations among markers even in the absence of any correlations within contemporaneous subgroups. The absence of any consistent correlations within years or demographic subgroups implies that care must be taken when generalizing from observed relationships with oxidative stress markers, as each marker may reflect different and potentially uncoupled biochemical processes.We would like to thank Melissa M. Page, Ruth Banks, Christopher Mitchell and Sharon Mitchell for technical assistance and the St Kilda summer field teams of 2010-2013. In addition, we are very grateful to the National Trust for Scotland for permission to carry out fieldwork on St Kilda, and QinetiQ, Angus Campbell and Kilda Cruises for logistic support. LLC was supported by a BBSRC EASTBIO Doctoral Training Partnership Studentship and DHN by a BBSRC David Phillips Fellowship. The Soay sheep project was supported by a NERC responsive mode grant to JMP over the course of our four-year study

Resistance to oxidative stress shows low heritability and high common environmental variance in a wild bird

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Oxidative stress was recently demonstrated to affect several fitness-related traits and is now well recognized to shape animal life-history evolution. However, very little is known about how much resistance to oxidative stress is determined by genetic and environmental effects and hence about its potential for evolution, especially in wild populations. In addition, our knowledge of phenotypic sexual dimorphism and cross-sex genetic correlations in resistance to oxidative stress remains extremely limited despite important evolutionary implications. In free-living great tits (Parus major), we quantified heritability, common environmental effect, sexual dimorphism and cross-sex genetic correlation in offspring resistance to oxidative stress by performing a split-nest cross-fostering experiment where 155 broods were split, and all siblings (n = 791) translocated and raised in two other nests. Resistance to oxidative stress was measured as both oxidative damage to lipids and erythrocyte resistance to a controlled free-radical attack. Both measurements of oxidative stress showed low additive genetic variances, high common environmental effects and phenotypic sexual dimorphism with males showing a higher resistance to oxidative stress. Cross-sex genetic correlations were not different from unity, and we found no substantial heritability in resistance to oxidative stress at adult age measured on 39 individuals that recruited the subsequent year. Our study shows that individual ability to resist to oxidative stress is primarily influenced by the common environment and has a low heritability with a consequent low potential for evolution, at least at an early stage of life.This work was conducted under licence of the Ethical Committee of the Agricultural Office of the Canton Bern. Ringing permits were provided by the Swiss Federal Agency for Environment, Forests and Landscapes. The authors thank Julien Martin and Matthew Wolak for helpful advice and David Costantini and two anonymous reviewers for constructive comments on previous versions of the manuscript. The study was financially supported by the Swiss National Science Foundation. SL was supported by a Swiss NSF and a Marie Curie IEF Post-Doctoral Fellowships. JDB was supported by a Royal Society Research Fellowship. The authors have declared no conflict of interest

No evidence of inbreeding depression in sperm performance traits in wild song sparrows

We thank the Tsawout and Tseycum first nations bands for allowing access to Mandarte, everyone who contributed to long-term field data collection, and Greta Bocedi and Lukas Keller for constructive comments. This study was funded by Marie Curie Actions, UK Royal Society, Swiss National Science Foundation, the Natural Sciences, Engineering Research Council of Canada and the European Research Council.Peer reviewedPublisher PD

Robotic-assisted percutaneous coronary intervention: experience in Switzerland

Aims of the studyPercutaneous coronary intervention (PCI) exposes operators to ionizing radiation. Robotic-assisted PCI (RA-PCI) is a novel technology that enables interventional cardiologists to operate coronary devices remotely from a radiation-shed cockpit. The aim of this study is to describe the experience and challenges during the initiation of a RA-PCI program and to report outcomes of the first 21 patients undergoing RA-PCI in Switzerland.MethodsAll patients undergoing RA-PCI using the CorPath GRX Vascular Robotic System between 06/2021 and 12/2021 at Inselspital, Bern University Hospital were included in this retrospective registry study. Baseline, procedural and clinical follow-up data were prospectively assessed as part of the Cardiobase Bern PCI registry (NCT02241291). The two endpoints of interest were clinical success [defined as <30% residual diameter stenosis in the absence of in-hospital major adverse cardiovascular events (MACE: composite of death, periprocedural myocardial infarction, target-vessel revascularization, and stroke)] and robotic success (defined as clinical success and completion of RA-PCI without or with partial manual assistance). Additional outcome measures include clinical long-term outcomes at one year.ResultsTwenty-five lesions in 21 patients were treated with RA-PCI (age 62.4 ± 9.1 years, 24% female). Clinical success was achieved in 100%, and robotic success in 81% (17/21 procedures, including 4 procedures requiring partial manual assistance). Manual conversion (e.g. manual completion of the procedure) occurred in 19% (4 procedures). Reasons for manual assistance or conversion were poor guiding-catheter back-up or platform limitations (4), adverse events (2x transient slow-flow that was solved manually), safety decision (1x vasovagal reaction not related to robotic approach), and software error (1). No in-hospital MACE occurred. During 12 months of follow-up, one patient suffered a non-target-vessel myocardial infarction requiring repeat PCI.ConclusionsRA-PCI can safely be performed without clinically relevant robot-associated complications in selected patients with approximately 80% of procedures conducted without or with partial manual assistance

Multivessel percutaneous coronary intervention with thin-strut biodegradable versus durable polymer drug-eluting stents in ST-segment-elevation myocardial infarction: A subgroup analysis of the BIOSTEMI randomized trial.

BACKGROUND Randomized evidence comparing newer-generation drug-eluting stents for multivessel percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) is limited. We sought to investigate clinical outcomes in STEMI patients undergoing multivessel PCI with thin-strut biodegradable polymer sirolimus-eluting stents (BP-SES) versus durable polymer everolimus-eluting stents (DP-EES). METHODS We performed a subgroup analysis of the BIOSTEMI (NCT02579031) randomized trial, which included individual patient data from STEMI patients enrolled into the BIOSCIENCE (NCT02579031) study. STEMI patients randomly allocated to BP-SES or DP-EES were divided into those undergoing multivessel versus culprit lesion-only PCI. The primary endpoint was target lesion failure (TLF), a composite of cardiac death, target-vessel myocardial re-infarction or clinically-indicated target lesion revascularization (TLR), within 24 months. RESULTS Among 1707 STEMI patients, 145 patients underwent multivessel PCI. At 2 years, TLF occurred in 2 patients (2.8%) treated with BP-SES and 13 patients (18.7%) treated with DP-EES (hazard ratio [HR], 0.14; 95% confidence interval (CI), 0.03-0.61; p = 0.009) in the multivessel PCI group, and in 40 (5.3%) and 61 (8.2%) patients treated with BP-SES and DP-EES respectively (HR, 0.64; 95%CI, 0.43-0.96; p = 0.03; p for interaction = 0.050) in the culprit lesion-only PCI group. In the multivessel PCI group, the rates of clinically-indicated TLR (0% vs. 12.4%) and target-vessel myocardial re-infarction (0% vs. 4.6%) at 2 years were lower in patients treated with BP-SES compared with DP-EES. CONCLUSION In a subgroup analysis of the BIOSTEMI trial, BP-SES were associated with lower 2-year TLF rates compared to DP-EES in STEMI patients undergoing multivessel PCI