title: Effects of early-developmental stress on growth rates, body composition and developmental plasticity of the HPG-axis.
abstract: In altricial songbirds, food restriction in early development has adverse effects on various physiological systems. When conditions improve birds can accelerate growth, but this compensatory strategy is associated with long-term adverse consequences. One system affected by altered growth rates is the hypothalamic-pituitary-gonadal (HPG) axis. Here, we subjected European starlings, Sturnus vulgaris, to an unpredictable food manipulation from 35 to 115days of age. We assessed the effects of the treatment by measuring overall body mass and body composition during and following the treatment period (i.e., accelerated growth). In adulthood, we measured the long-term effects of the treatment on overall body mass, testis volume, and HPG axis function in both sexes by quantifying androgen levels before and after a gonadotropin-releasing hormone (GnRH) challenge. During the treatment period, treatment birds had less body fat than controls. Following the treatment period, treatment birds weighed more than controls, but these gains were attributed to changes in lean mass. In adulthood, treatment males had lower baseline androgen levels, but there was no difference in peak androgen levels compared to controls. Treatment females did not differ from controls on any of the androgen measures. However, females that accelerated growth faster following the termination of the treatment had lower integrated androgen levels. When faced with limited developmental resources, birds may alter the developmental trajectory of physiological systems as a compensatory strategy. Such a strategy may have long-term consequences on endocrine regulation that could affect courtship and reproductive behaviors.
authors.affiliation: Department of Psychology, University of Western Ontario, Canada; Advanced Facility for Avian Research, University of Western Ontario, Canada. Electronic address: tfarrel2@uwo.ca.
authors.forename: Tara M
authors.initials: TM
authors.lastname: Farrell
authors.affiliation: Department of Biology, University of Western Ontario, Canada; Advanced Facility for Avian Research, University of Western Ontario, Canada.
authors.forename: Amanda
authors.initials: A
authors.lastname: Morgan
authors.affiliation: Department of Biology, University of Western Ontario, Canada; Advanced Facility for Avian Research, University of Western Ontario, Canada.
authors.forename: Yanina
authors.initials: Y
authors.lastname: Sarquis-Adamson
authors.affiliation: Department of Psychology, University of Western Ontario, Canada; Department of Biology, University of Western Ontario, Canada; Advanced Facility for Avian Research, University of Western Ontario, Canada.
authors.forename: Scott A
authors.initials: SA
authors.lastname: MacDougall-Shackleton
mesh_terms: D000818:Animals; D001823:Body Composition / Q000502:physiology*; D004703:Endocrine System / Q000002:abnormalities*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism* / Q000494:pharmacology; D008297:Male; D020308:Songbirds / Q000254:growth & development*
chemical_list: D007987:Gonadotropin-Releasing Hormone
keywords: Body composition; Compensatory growth; Developmental plasticity; Developmental stress; GnRH; HPG axis