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Navara KJ, Mendonça MT, Gardner S. Dietary yolk supplements and rate of yolk deposition do not influence sex ratios in Japanese Quail. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:749-754. [PMID: 37366001 DOI: 10.1002/jez.2724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/28/2023]
Abstract
Birds appear to have the ability to bias offspring sex ratios in response to environmental and social conditions. The mechanisms responsible remain unknown, however one previous study indicated a link between rates of ovarian follicle growth and the sexes of resulting eggs. This could indicate that either follicles destined to retain male or female follicles grow at different rates, or the rate of ovarian follicle growth determines the sex chromosome that will be retained to influence the sex of the resulting offspring. We tested for evidence of both possibilities by staining yolk rings that are indicative of daily growth. First, we tested for a correlation between the number of yolk rings and the sexes of the resulting germinal discs collected from each egg, and second, we tested whether experimentally decreasing follicle growth rates with a dietary yolk supplement impacts the sexes of the resulting germinal discs. There was no significant correlation between the number of yolk rings and the sexes of the resulting embryos, and decreasing follicle growth rates did not impact sexes of resulting germinal discs. These results indicate that offspring sex is not related to the rate of ovarian follicle growth in quail.
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Affiliation(s)
- Kristen J Navara
- Department of Poultry Science, The University of Georgia, Athens, Georgia, USA
| | - Mary T Mendonça
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Steven Gardner
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
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2
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Rittinger MA, Bowden RM, Sauers LA, Paitz RT, Poppe CJ, Thompson CF, Sakaluk SK. Sex-specific effects of hatching order on nestling baseline corticosterone in a wild songbird. Gen Comp Endocrinol 2022; 319:113964. [PMID: 34922951 DOI: 10.1016/j.ygcen.2021.113964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 11/27/2022]
Abstract
Variation in nestling growth and survival is often influenced by hatching order, with first-hatched offspring having an advantage over later-hatched younger siblings. In house wrens (Troglodytes aedon), this effect of hatching order is especially evident in asynchronously hatched broods and can lead to sex-specific differences in the size and condition of nestlings. Females appear to allocate the sex of their offspring across the laying order to capitalize on these differences. We hypothesized that levels of circulating corticosterone, the primary metabolic hormone in birds, mediates these sex-specific effects in nestlings. We predicted that: i) baseline levels of corticosterone in nestlings should vary along the hatching order, ii) effects of hatching order on baseline corticosterone should be sex specific, and iii) any sex-specificity of hatching order on baseline corticosterone could be contingent on the degree of hatching synchrony. We tested these predictions in a study in which we measured baseline corticosterone in first- and last-hatched nestlings in synchronously and asynchronously hatching broods. To assess whether any differences in nestling baseline corticosterone levels could be attributed to pre-natal maternal effects, the post-natal environment, or both, we conducted two additional studies in which we measured i) yolk corticosterone in first- and last-laid eggs and ii) baseline corticosterone in nestlings that were cross-fostered to create simulated 'asynchronously' hatched broods. There was a significant interaction between sex and relative hatching order in their effects on nestling baseline corticosterone, but no effect of hatching synchrony. Corticosterone levels remained relatively constant across the hatching order in males but decreased in females. There was a significant effect of laying order on yolk corticosterone, with first-laid eggs containing significantly higher levels of yolk corticosterone than last-laid eggs. Cross-fostering of nestlings at different points of development had no significant effect on nestling corticosterone levels. These results indicate that sex-dependent differences in corticosterone levels across the hatching order may arise, at least in part, from embryonic exposure to maternally derived corticosterone, whereas the post-natal rearing environment plays, at best, a minimal role in determining nestling baseline corticosterone levels.
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Affiliation(s)
- Madison A Rittinger
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA.
| | - Rachel M Bowden
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Logan A Sauers
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Ryan T Paitz
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Christine J Poppe
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Charles F Thompson
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - Scott K Sakaluk
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
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3
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Miltiadous A, Buchanan KL. Experimental manipulation of maternal corticosterone: Hormone transfer to the yolk in the zebra finch Taeniopygia guttata. Gen Comp Endocrinol 2021; 313:113898. [PMID: 34492223 DOI: 10.1016/j.ygcen.2021.113898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/28/2021] [Accepted: 08/28/2021] [Indexed: 10/20/2022]
Abstract
Maternally-derived hormones affect offspring physiological and behavioural phenotype, plausibly as an adaptive response to maternal environmental conditions. Corticosterone (CORT), the principal avian glucocorticoid produced in response to stress, is recognised as a potential mediator of such maternal reproductive effects. Maternally-derived yolk CORT is implicated in mediating offspring growth and hatchling begging behaviour. However, determining the potential for maternal effects in opportunistic breeders subject to variable environments relies on understanding whether natural variation in maternal circulating hormones may directly impact the embryo during development. Therefore, we tested whether elevated maternal CORT concentrations increase yolk CORT concentrations in zebra finch (Taeniopygia guttata) eggs. We remotely dosed breeding females with biologically-relevant doses of CORT, or the oil vehicle, 0-3 h prior to the predicted time of ovulation, and allowed pairs to produce two clutches, one under each treatment, in a crosswise, balanced design. CORT dosing elevated maternal plasma CORT and increased mean yolk CORT by a factor of 1.75 compared to the egg yolks of control mothers. Importantly, CORT concentrations did not differ between inner and outer layers of yolk. We found no egg lay order effect and maternal CORT dosing did not influence reproductive outputs (clutch initiation date, clutch size or egg mass). Our results confirm the direct impact of biologically-relevant increases in maternal CORT on yolk CORT, providing evidence that maternal CORT concentrations during yolk deposition to the follicle alters embryonic exogenous CORT exposure. Further research is required to determine the impact of maternal CORT on embryonic developmental programming.
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Affiliation(s)
- Anna Miltiadous
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia.
| | - Katherine L Buchanan
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
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4
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Wrobel ER, Bentz AB, Lorenz WW, Gardner ST, Mendonça MT, Navara KJ. Corticosterone and testosterone treatment influence expression of gene pathways linked to meiotic segregation in preovulatory follicles of the domestic hen. PLoS One 2020; 15:e0232120. [PMID: 32407351 PMCID: PMC7224459 DOI: 10.1371/journal.pone.0232120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 04/07/2020] [Indexed: 01/25/2023] Open
Abstract
Decades of work indicate that female birds can control their offspring sex ratios in response to environmental and social cues. In laying hens, hormones administered immediately prior to sex chromosome segregation can exert sex ratio skews, indicating that these hormones may act directly on the germinal disc to influence which sex chromosome is retained in the oocyte and which is discarded into an unfertilizable polar body. We aimed to uncover the gene pathways involved in this process by testing whether treatments with testosterone or corticosterone that were previously shown to influence sex ratios elicit changes in the expression of genes and/or gene pathways involved in the process of meiotic segregation. We injected laying hens with testosterone, corticosterone, or control oil 5h prior to ovulation and collected germinal discs from the F1 preovulatory follicle in each hen 1.5h after injection. We used RNA-sequencing (RNA-seq) followed by DESeq2 and gene set enrichment analyses to identify genes and gene pathways that were differentially expressed between germinal discs of control and hormone-treated hens. Corticosterone treatment triggered downregulation of 13 individual genes, as well as enrichment of gene sets related to meiotic spindle organization and chromosome segregation, and additional gene sets that function in ion transport. Testosterone treatment triggered upregulation of one gene, and enrichment of one gene set that functions in nuclear chromosome segregation. This work indicates that corticosterone can be a potent regulator of meiotic processes and provides potential gene targets on which corticosterone and/or testosterone may act to influence offspring sex ratios in birds.
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Affiliation(s)
- Elizabeth R. Wrobel
- Department of Poultry Science, The University of Georgia, Athens, GA, United States of America
| | - Alexandra B. Bentz
- Department of Biology, Indiana University, Bloomington, IN, United States of America
| | - W. Walter Lorenz
- Institute of Bioinformatics and Georgia Genomics and Bioinformatics Core, The University of Georgia, Athens, GA, United States of America
| | - Stephen T. Gardner
- Department of Biological Sciences, Auburn University, Auburn, AL, United States of America
| | - Mary T. Mendonça
- Department of Biological Sciences, Auburn University, Auburn, AL, United States of America
| | - Kristen J. Navara
- Department of Poultry Science, The University of Georgia, Athens, GA, United States of America
- * E-mail:
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Wrobel ER, Molina E, Khan NY, Akingbemi BT, Mendonca MT, Navara KJ. Androgen and mineralocorticoid receptors are present on the germinal disc region in laying hens: Potential mediators of sex ratio adjustment in birds? Gen Comp Endocrinol 2020; 287:113353. [PMID: 31809721 DOI: 10.1016/j.ygcen.2019.113353] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 11/26/2019] [Accepted: 12/01/2019] [Indexed: 11/21/2022]
Abstract
Female birds skew offspring sex ratios based on environmental and social stimuli; however, the mechanism mediating this phenomenon remains unknown. Growing evidence suggests that testosterone and corticosterone may influence meiosis, as they skew sex ratios when given immediately before chromosomal segregation. It is unclear if these hormones act on the germinal disc (GD) or through a downstream mediator. It is also unknown whether the GD contains receptors for these hormones. If testosterone and/or corticosterone act on the GD to skew sex ratios, then the GD should have receptors for them and that receptor levels should be higher in the GD regions compared to other follicular regions. Furthermore, fluctuations of receptor levels should occur near meiotic segregation. We collected ovarian follicles at 5 h pre-ovulation (just before meiotic segregation) and 20 h pre-ovulation (when sex chromosomes are arrested), and measured androgen receptor (AR) and mineralocorticoid receptor (MR) protein levels via Western blot. ARs and MRs were on the follicle in the GD and non-GD regions, and at 5 h and 20 h pre-ovulation. Both AR and MR protein levels were higher in the GD region than the non-GD region at both time points, but did not differ between time points. These results suggest that hen ovarian follicles have receptors for testosterone and corticosterone, and that the ability for testosterone to respond may be specifically higher in the GD-region, providing further support for the role of testosterone in the alteration of meiotic segregation.
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Affiliation(s)
- Elizabeth R Wrobel
- Poultry Science Department, University of Georgia, 203 Poultry Science Bldg., Athens, GA 30602, USA.
| | - Erica Molina
- Biological Sciences Department, Auburn University, 331 Funchess Hall, Auburn, AL 36849, USA
| | - Nicola Y Khan
- School of Psychology and Neuroscience, University of St. Andrews, South Street, St. Andrews KY16 9JP, Scotland, UK
| | - Benson T Akingbemi
- Department of Anatomy, Physiology and Pharmacology, Auburn University, 109 Greene Hall, College of Veterinary Medicine, Auburn, AL 36849, USA
| | - Mary T Mendonca
- Biological Sciences Department, Auburn University, 331 Funchess Hall, Auburn, AL 36849, USA
| | - Kristen J Navara
- Poultry Science Department, University of Georgia, 203 Poultry Science Bldg., Athens, GA 30602, USA
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6
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The Adaptive Sex in Stressful Environments. Trends Ecol Evol 2019; 34:628-640. [PMID: 30952545 DOI: 10.1016/j.tree.2019.02.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 01/10/2023]
Abstract
The impact of early stress on juvenile development has intrigued scientists for decades, but the adaptive significance of such effects remains an ongoing debate. This debate has largely ignored some characteristics of the offspring, such as their sex, despite strong evolutionary and demographic implications of sex-ratio variation. We review recent studies that examine associations between glucocorticoids (GCs), the main class of stress hormones, and offspring sex. Whereas exposure to GCs at around the time of sex determination in fish consistently produces males, the extent and direction of sex-ratio bias in response to stress vary in reptiles, birds, and mammals. We propose proximate and ultimate explanations for most of these trends.
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Podmokła E, Drobniak SM, Rutkowska J. Chicken or egg? Outcomes of experimental manipulations of maternally transmitted hormones depend on administration method - a meta-analysis. Biol Rev Camb Philos Soc 2018; 93:1499-1517. [PMID: 29573376 DOI: 10.1111/brv.12406] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 01/28/2018] [Accepted: 02/13/2018] [Indexed: 12/25/2022]
Abstract
Steroid hormones are important mediators of prenatal maternal effects in animals. Despite a growing number of studies involving experimental manipulation of these hormones, little is known about the impact of methodological differences among experiments on the final results expressed as offspring traits. Using a meta-analytical approach and a representative sample of experimental studies performed on birds, we tested the effect of two types of direct hormonal manipulations: manipulation of females (either by implantation of hormone pellets or injection of hormonal solutions) and manipulation of eggs by injection. In both types of manipulation we looked at the effects of two groups of hormones: corticosterone and androgens in the form of testosterone and androstenedione. We found that the average effect on offspring traits differed between the manipulation types, with a well-supported positive effect of egg manipulation and lack of a significant effect of maternal manipulation. The observed average positive effect for egg manipulation was driven mainly by androgen manipulations, while corticosterone manipulations exerted no overall effect, regardless of manipulation type. Detailed analyses revealed effects of varying size and direction depending on the specific offspring traits; e.g., egg manipulation positively affected physiology and behaviour (androgens), and negatively affected future reproduction (corticosterone). Effect size was negatively related to the dose of androgen injected into the eggs, but unrelated to timing of manipulation, offspring developmental stage at the time of measuring their traits, solvent type, the site of egg injection and maternal hormone delivery method. Despite the generally acknowledged importance of maternal hormones for offspring development in birds, the overall effect of their experimental elevation is rather weak, significantly heterogeneous and dependent on the hormone and type of manipulation. We conclude by providing general recommendations as to how hormonal manipulations should be performed in order to standardize their impact and the results achieved. We also emphasize the need for research on free-living birds with a focus on fitness-related and other long-term effects of maternal hormones.
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Affiliation(s)
- Edyta Podmokła
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Szymon M Drobniak
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Joanna Rutkowska
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
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8
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9
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Ahmed AA, Musa HH, Sifaldin AZ. Prenatal corticosterone exposure programs growth, behavior, reproductive function and genes in the chicken. ASIAN PACIFIC JOURNAL OF REPRODUCTION 2016. [DOI: 10.1016/j.apjr.2016.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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10
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Aslam MA, Schokker D, Groothuis TG, de Wit AA, Smits MA, Woelders H. Association of Egg Mass and Egg Sex: Gene Expression Analysis from Maternal RNA in the Germinal Disc Region of Layer Hens (Gallus gallus)1. Biol Reprod 2015; 92:157. [DOI: 10.1095/biolreprod.114.123380] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 03/19/2015] [Indexed: 11/01/2022] Open
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Pinson SE, Wilson JL, Navara KJ. Timing matters: corticosterone injections 4 h before ovulation bias sex ratios towards females in chickens. J Comp Physiol B 2015; 185:539-46. [DOI: 10.1007/s00360-015-0897-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 02/10/2015] [Accepted: 03/01/2015] [Indexed: 10/23/2022]
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12
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Henderson LJ, Evans NP, Heidinger BJ, Adams A, Arnold KE. Maternal condition but not corticosterone is linked to offspring sex ratio in a passerine bird. PLoS One 2014; 9:e110858. [PMID: 25347532 PMCID: PMC4210198 DOI: 10.1371/journal.pone.0110858] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 09/22/2014] [Indexed: 11/19/2022] Open
Abstract
There is evidence of offspring sex ratio adjustment in a range of species, but the potential mechanisms remain largely unknown. Elevated maternal corticosterone (CORT) is associated with factors that can favour brood sex ratio adjustment, such as reduced maternal condition, food availability and partner attractiveness. Therefore, the steroid hormone has been suggested to play a key role in sex ratio manipulation. However, despite correlative and causal evidence CORT is linked to sex ratio manipulation in some avian species, the timing of adjustment varies between studies. Consequently, whether CORT is consistently involved in sex-ratio adjustment, and how the hormone acts as a mechanism for this adjustment remains unclear. Here we measured maternal baseline CORT and body condition in free-living blue tits (Cyanistes caeruleus) over three years and related these factors to brood sex ratio and nestling quality. In addition, a non-invasive technique was employed to experimentally elevate maternal CORT during egg laying, and its effects upon sex ratio and nestling quality were measured. We found that maternal CORT was not correlated with brood sex ratio, but mothers with elevated CORT fledged lighter offspring. Also, experimental elevation of maternal CORT did not influence brood sex ratio or nestling quality. In one year, mothers in superior body condition produced male biased broods, and maternal condition was positively correlated with both nestling mass and growth rate in all years. Unlike previous studies maternal condition was not correlated with maternal CORT. This study provides evidence that maternal condition is linked to brood sex ratio manipulation in blue tits. However, maternal baseline CORT may not be the mechanistic link between the maternal condition and sex ratio adjustment. Overall, this study serves to highlight the complexity of sex ratio adjustment in birds and the difficulties associated with identifying sex biasing mechanisms.
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Affiliation(s)
- Lindsay J. Henderson
- Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, California, United States of America
- College of Medical, Veterinary & Life Sciences, The University of Glasgow, Glasgow, United Kingdom
| | - Neil P. Evans
- College of Medical, Veterinary & Life Sciences, The University of Glasgow, Glasgow, United Kingdom
| | - Britt J. Heidinger
- College of Medical, Veterinary & Life Sciences, The University of Glasgow, Glasgow, United Kingdom
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Aileen Adams
- College of Medical, Veterinary & Life Sciences, The University of Glasgow, Glasgow, United Kingdom
| | - Kathryn E. Arnold
- College of Medical, Veterinary & Life Sciences, The University of Glasgow, Glasgow, United Kingdom
- Environment Department, The University of York, York, United Kingdom
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13
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Neuman-Lee LA, Gaines KF, Baumgartner KA, Voorhees JR, Novak JM, Mullin SJ. Assessing multiple endpoints of atrazine ingestion on gravid Northern Watersnakes (Nerodia sipedon) and their offspring. ENVIRONMENTAL TOXICOLOGY 2014; 29:1072-1082. [PMID: 23436772 DOI: 10.1002/tox.21837] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 12/07/2012] [Indexed: 06/01/2023]
Abstract
Ecotoxicological studies that focus on a single endpoint might not accurately and completely represent the true ecological effects of a contaminant. Exposure to atrazine, a widely used herbicide, disrupts endocrine function and sexual development in amphibians, but studies involving live-bearing reptiles are lacking. This study tracks several effects of atrazine ingestion from female Northern Watersnakes (Nerodia sipedon) to their offspring exposed in utero. Twenty-five gravid N. sipedon were fed fish dosed with one of the four levels of atrazine (0, 2, 20, or 200 ppb) twice weekly for the entirety of their gestation period. Endpoints for the mothers included blood estradiol levels measured weekly and survival more than 3 months. Endpoints for the offspring included morphometrics, clutch sex ratio, stillbirth, and asymmetry of dorsal scales and jaw length. Through these multiple endpoints, we show that atrazine ingestion can disrupt estradiol production in mothers, increase the likelihood of mortality from infection, alter clutch sex ratio, cause a higher proportion of stillborn offspring, and affect scale symmetry. We emphasize the need for additional research involving other reptile species using multiple endpoints to determine the full range of impacts of contaminant exposure.
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Affiliation(s)
- Lorin A Neuman-Lee
- Department of Biological Sciences, Eastern Illinois University, Charleston, Illinois 61920, USA
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14
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Aslam MA, Groothuis TG, Smits MA, Woelders H. Effect of Corticosterone and Hen Body Mass on Primary Sex Ratio in Laying Hen (Gallus gallus), Using Unincubated Eggs1. Biol Reprod 2014; 90:76. [DOI: 10.1095/biolreprod.113.115352] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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15
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Ramachandran R. Current and future reproductive technologies for avian species. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 752:23-31. [PMID: 24170353 DOI: 10.1007/978-1-4614-8887-3_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The global demand for poultry meat and eggs is expected to increase exponentially in the next several decades. Increasing global poultry production in the future would require significant improvements in genetics, nutrition, and managerial practices including reproduction. This chapter summarizes some of the recent developments in ameliorating reproductive dysfunction in broiler breeder chickens, cryopreservation of avian spermatozoa, sex selection, and avian transgenesis.
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Affiliation(s)
- Ramesh Ramachandran
- Department of Animal Science, Center for Reproductive Biology and Health, The Pennsylvania State University, 211 Henning Building, University Park, PA, 16802, USA,
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16
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Boncoraglio G, Groothuis TGG. Effect of rapid modulation of circulating plasma testosterone concentration on begging, aggressive behavior and competition for food in black-headed gull (Larus ridibundus) chicks. Horm Behav 2013; 64:487-93. [PMID: 23962563 DOI: 10.1016/j.yhbeh.2013.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 07/06/2013] [Accepted: 08/09/2013] [Indexed: 11/18/2022]
Abstract
Sibling competition mediated by begging behavior is extremely common in avian species and recent studies have highlighted the role of endogenous testosterone in regulating such phenomenon. However, current literature depicts an inconsistent pattern in altricial vs. semi-precocial species, with stimulating versus inhibitory effects of the hormone respectively. This is possibly due to a difference in the methodology of hormone treatment (short-term moderate dose versus a long-term stronger elevation, respectively) between the studies performed so far. In this study, we induced short-term moderate peaks in plasma testosterone levels, as applied in altricial bird species, and assessed the effects of our manipulation on begging, competitive and aggressive behavior in black-headed gull (Larus ridibundus) chicks, a semi-precocial species. Our results suggest that, unlike in altricial songbirds, temporary increase of plasma testosterone concentration suppresses begging and enhances aggressiveness towards intruders. However, it also increases aggression and the chances of getting priority while scrambling with nest mates to gain access to food. Thus, the inconsistencies in the hormonal control of begging behavior observed between altricial vs. semi-precocial birds seem real and perhaps related to species differences in complexity of the display and the nature of competition. These may be elucidated by future comparative studies.
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Affiliation(s)
- Giuseppe Boncoraglio
- Behavioural Biology, University of Groningen, Centre for Behaviour and Neuroscience, Nijenborgh 7, 9747AG, Groningen The Netherlands; Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, I-20133 Milano, Italy.
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17
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Navara KJ. The role of steroid hormones in the adjustment of primary sex ratio in birds: compiling the pieces of the puzzle. Integr Comp Biol 2013; 53:923-37. [PMID: 23900275 DOI: 10.1093/icb/ict083] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
There is ample evidence that birds have the ability to adjust their offsprings' sex ratios before fertilization occurs. Recent work has focused on pinpointing when during the process of oocyte maturation adjustment of sex ratio takes place. Additionally, there is growing support for the idea that there is hormonal control over the process of adjustment of sex ratio in birds. Whether steroid hormones represent direct mediators of the process, however, remains unclear. This review outlines the precise points during maturation of ovarian follicles during which adjustment of primary sex ratios could potentially occur, compiles the evidence for hormonal involvement in the process of primary adjustment of sex ratio, and discusses potential hormonal targets during maturation and fertilization of oocytes where hormones may trigger adjustment of sex ratio in birds.
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Affiliation(s)
- Kristen J Navara
- Department of Poultry Science, The University of Georgia, Athens, GA 30602, USA
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18
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Abstract
The ability to adjust sex ratios at the individual level exists among all vertebrate groups studied to date. In many cases, there is evidence for facultative adjustment of sex ratios in response to environmental and/or social cues. Because environmental and social information must be first transduced into a physiological signal to influence sex ratios, hormones likely play a role in the adjustment of sex ratio in vertebrates, because the endocrine system acts as a prime communicator that directs physiological activities in response to changing external conditions. This symposium was developed to bring together investigators whose work on adjustment of sex ratio represents a variety of vertebrate groups in an effort to draw comparisons between species in which the sex-determination process is well-established and those in which more work is needed to understand how adjustments in sex ratio are occurring. This review summarizes potential hormone targets that may underlie the mechanisms of adjustment of sex ratio in humans, non-human mammals, birds, reptiles, and fishes.
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Affiliation(s)
- Kristen J Navara
- Department of Poultry Science, The University of Georgia, Athens, GA 30602, USA
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Aslam MA, Hulst M, Hoving-Bolink RAH, Smits MA, de Vries B, Weites I, Groothuis TGG, Woelders H. Yolk concentrations of hormones and glucose and egg weight and egg dimensions in unincubated chicken eggs, in relation to egg sex and hen body weight. Gen Comp Endocrinol 2013; 187:15-22. [PMID: 23510857 DOI: 10.1016/j.ygcen.2013.02.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 02/13/2013] [Accepted: 02/24/2013] [Indexed: 11/15/2022]
Abstract
Birds can manipulate offspring sex ratio under natural and experimental conditions and maternal hormones have been shown to be involved in this process. Studies also provided evidence for the presence of sex specific concentrations of yolk hormones in avian eggs. These findings led to the suggestion that yolk hormones could influence genetic sex determination in birds. However, in previous studies, yolk hormone concentrations and egg sex were studied in incubated eggs, although incubation of the eggs and embryonic development can alter yolk hormone concentrations and measured sex ratio. This study is the first to determine a wide array of egg components and hen body weight in relation to the sex of the egg in unincubated eggs. Egg parameters studied were yolk concentrations of testosterone, estradiol, androstenedione, progesterone, dihydrotestosterone, and glucose, and egg weight and dimensions. In addition, we studied the associations among all measured parameters. Associations were found between a number of yolk hormones (progesterone associated with testosterone, estradiol and androstenedione; androstenedione with testosterone; dihydrotestosterone with estradiol and androstenedione) as well as between yolk testosterone and egg length and egg weight. There were no significant overall differences between male and female chicken eggs in any of the measured egg parameters. However, there were a few interactions such as the interaction of egg sex with dihydrotestosterone and with hen body weight which predicted estradiol levels and an interaction of estradiol levels with egg width for predicting sex of egg. Their biological relevance need, however, further study.
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Affiliation(s)
- M Aamir Aslam
- Animal Breeding and Genomics Centre, Wageningen UR Livestock Research, PO Box 65, 8200 AB Lelystad, The Netherlands
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Tagirov M, Rutkowska J. Chimeric embryos—potential mechanism of avian offspring sex manipulation. Behav Ecol 2013. [DOI: 10.1093/beheco/art007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Pinson SE, Wilson JL, Navara KJ. Elevated testosterone during meiotic segregation stimulates laying hens to produce more sons than daughters. Gen Comp Endocrinol 2011; 174:195-201. [PMID: 21925503 DOI: 10.1016/j.ygcen.2011.08.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 08/22/2011] [Accepted: 08/24/2011] [Indexed: 11/25/2022]
Abstract
Biases in avian sex ratios have been documented in relation to a variety of social and environmental conditions. Previous studies suggest that treatment with hormones can stimulate females to manipulate offspring sex, and that this effect occurs before ovulation. For example, acute and chronic treatments with testosterone stimulated significant skews towards male offspring. Hormones may act by influencing which sex chromosome is donated by the heterogametic female bird into the oocyte. However, it is difficult to pinpoint when effects of testosterone on offspring sex occurred in previous experiments because testosterone treatments were given either chronically over the entire period of follicular development or many hours before the critical period of chromosome segregation. We injected laying hens with testosterone injections 5 h prior to ovulation to target this critical period and quantified the sexes of the subsequently ovulated eggs. We hypothesized that an injection of testosterone coincident with segregation of sex chromosomes would stimulate hens to produce more male than female offspring. As hypothesized, hens injected with testosterone produced a significant bias towards male offspring compared to controls, nearly 70%. These results suggest that acute testosterone elevation during meiotic segregation may mediate skews in avian primary sex ratios.
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Affiliation(s)
- Sara E Pinson
- Department of Poultry Science, University of Georgia, Athens, GA 30602, USA.
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