Oxidative stress affects sperm performance and ejaculate redox status in subordinate house sparrows
Alfonso Luis Rojas Mora, Alexandra Firth, Sophie Blareau, Armelle Vallat & Fabrice Helfenstein
| Résumé |
Oxidative stress (OS) is the result of random cellular damage caused
by reactive oxygen species that leads to cell death, ageing, or
illness. Most physiological processes can result in OS, which in
turn has been identified as a major cause of infertility. In
promiscuous species, the fertilizing ability of the ejaculate
partly determines the male reproductive success. When dominance
determines access to fertile females, theory predicts that lower
ranking males should increase resource investment into enhancing
ejaculate quality. We hypothesized that subordinate males should
thus prioritize antioxidant protection of their ejaculates to
protect them from OS. We put this hypothesis to the test, by
chronically dosing wild House Sparrows with diquat (∼1mg/kg),
an herbicide that increases pro-oxidant generation. We found that,
although they increased their antioxidant levels in the ejaculate,
diquat-treated males produced sperm with reduced velocity.
Importantly, and contrary to our hypothesis, males at the bottom of
the hierarchy suffered the largest reduction in sperm velocity. We
suggest that resource access hinders individuals' ability to cope
with environmental hazards. Our results point at OS as a likely
physiological mechanism mediating ejaculate quality, while
individual ability to access resources may play a role in
constraining the extent to which such resources can be allocated
into the ejaculate. |
| Mots-clés |
oxidative stress, Social dominance, soma/germline allocation trade-off, sperm competition, sperm velocity, sperm motility, SOD, superoxide dismutase, Glutathione, pollutants, reproductive strategy, reproductive physiology |
| Citation | Luis Rojas Mora, A., Firth, A., Blareau, S., Vallat, A., & Helfenstein, F. (2017). Oxidative stress affects sperm performance and ejaculate redox status in subordinate house sparrows. Journal of Experimental Biology, 220, 2577-2588. |
| Type | Article de périodique (Anglais) |
| Date de publication | 15-5-2017 |
| Nom du périodique | Journal of Experimental Biology |
| Volume | 220 |
| Pages | 2577-2588 |
| Liée au projet | Oxidative stress in avian semen: causes and consequences ... |