caa a22 4500 605514461 CHVBK 20210128100704.0 cr unu---uuuuu 210128e20150701xx s 000 0 eng 10.1007/s00360-015-0897-5 doi (NATIONALLICENCE)springer-10.1007/s00360-015-0897-5 Timing matters: corticosterone injections 4h before ovulation bias sex ratios towards females in chickens [Elektronische Daten] [Sara Pinson, Jeanna Wilson, Kristen Navara] Birds have the ability to influence offspring sex prior to egg laying and may use hormones to mediate these skews. Corticosterone is of particular interest as a mediator of offspring sex because, as the primary stress hormone in birds, it regulates responses to environmental and social stimuli that trigger sex ratio biases. In previous studies in birds, chronic elevations of corticosterone stimulated female-biased sex ratios while acute pharmacological elevations that were provided 5h prior to the expected time of ovulation stimulated male-biased sex ratios. Here, we aimed to determine the magnitude of corticosterone necessary to influence offspring sex and to further pinpoint the timing of the hormonal influence. Because high-dose injections of corticosterone stimulated male-biased sex ratios in hens, we hypothesized that females receiving acute pharmacological elevations of corticosterone would produce more male offspring while females with acute physiological elevations would produce an intermediate proportion of males compared to controls. We tested our hypotheses in laying hens by elevating corticosterone in the physiological or pharmacological range through injections of corticosterone administered 4 or 5h prior to the expected time of ovulation. Contrary to our hypothesis, a physiological dose of corticosterone provided 5h prior to the expected time of ovulation did not bias offspring sex ratios when compared to controls. Further, when corticosterone injections were given at 4h prior to the expected time of ovulation, sex ratios were instead biased towards females. These results suggest that the timing and magnitude of the corticosterone elevation are both critical not only to whether a sex ratio bias occurs, but also the direction of the bias. Springer-Verlag Berlin Heidelberg, 2015 Primary sex ratio nationallicence Offspring sex nationallicence Corticosterone nationallicence Stress nationallicence Maternal effects nationallicence Pinson Sara Department of Poultry Science, University of Georgia, 110 Cedar Street, 203 Poultry Science Building, 30602, Athens, GA, USA aut Wilson Jeanna Department of Poultry Science, University of Georgia, 110 Cedar Street, 203 Poultry Science Building, 30602, Athens, GA, USA aut Navara Kristen Department of Poultry Science, University of Georgia, 110 Cedar Street, 203 Poultry Science Building, 30602, Athens, GA, USA aut Journal of Comparative Physiology B Springer Berlin Heidelberg 185/5(2015-07-01), 539-546 0174-1578 185:5<539 2015 185 360 https://doi.org/10.1007/s00360-015-0897-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00360-015-0897-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pinson Sara Department of Poultry Science, University of Georgia, 110 Cedar Street, 203 Poultry Science Building, 30602, Athens, GA, USA aut NATIONALLICENCE 700 1- Wilson Jeanna Department of Poultry Science, University of Georgia, 110 Cedar Street, 203 Poultry Science Building, 30602, Athens, GA, USA aut NATIONALLICENCE 700 1- Navara Kristen Department of Poultry Science, University of Georgia, 110 Cedar Street, 203 Poultry Science Building, 30602, Athens, GA, USA aut NATIONALLICENCE 773 0- Journal of Comparative Physiology B Springer Berlin Heidelberg 185/5(2015-07-01), 539-546 0174-1578 185:5<539 2015 185 360