|
|
|
|||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online December 1, 2006
Journal of Experimental Biology 209, 4957-4965 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02610
Corticosterone selectively decreases humoral immunity in female eiders during incubation
Institut Pluridisciplinaire Hubert Curien (IPHC), Département Ecologie, Physiologie et Ethologie (DEPE), UMR 7178 CNRS-ULP, 23 rue Becquerel, F-67087 Strasbourg Cedex 2, France
* Author for correspondence (e-mail: sophie.bourgeon{at}c-strasbourg.fr)
Accepted 23 October 2006
Immunity is hypothesized to share limited resources with other physiological functions and this may partly account for the fitness costs of reproduction. Previous studies have shown that the acquired immunity of female common eider ducks (Somateria mollissima) is suppressed during their incubation, during which they entirely fast. Corticosterone was proposed to be an underlying physiological mechanism for such immunosuppression. Therefore, the current study aimed to assess the effects of exogenous corticosterone on acquired immunity in captive eiders. To this end, females were implanted with corticosterone pellets at different stages of their incubation fast. We measured total immunoglobulin levels, T-cell-mediated immune response, body mass and corticosterone levels in these females and compared them with those of control females prior to and after manipulation (i.e. corticosterone pellet implantation). To mimic corticosterone effects on body mass, we experimentally extended fasting duration in a group of females termed `late fasters'. Implanted females had corticosterone levels 6 times higher and lost 35% more mass than control females. Corticosterone levels in `late fasters' were similar to those in control females but body mass was 8% lower in the former. The decrease in the immunoglobulin levels of corticosterone implanted females was twice as high as in control females, while the T-cell-mediated immune response was not significantly affected by the treatment. We found a decrease in the T-cell-mediated immune response only in `late fasters' (by 60%), while the immunoglobulin level was not lower in this group than in corticosterone implanted or control females. Our study shows that in incubating eiders, exogenous corticosterone only decreased humoral immunity. We suggest that the immunosuppressive effect of corticosterone could be mediated through its effects on body reserves. Further experiments are required to determine the relationship between body condition and immune system in fasting birds.
Key words: bird, body reserve, fasting, glucocorticoid, immunosuppression
Related articles in JEB:
This article has been cited by other articles:
![]() |
L. Blackburn IMMUNE COSTS OF INCUBATING EGGS J. Exp. Biol., December 15, 2006; 209(24): iii - iii. [Full Text] [PDF] |
||||