This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Berg, C Articles by Ridderstråle, Y Search for Related Content PubMed PubMed Citation Articles by Berg, C Articles by Ridderstråle, Y

Embryonic exposure to oestrogen causes eggshell thinning and altered shell gland carbonic anhydrase expression in the domestic hen

Department of Environmental Toxicology, Uppsala University, Norbyvägen 18 A, 753 36 Uppsala, Sweden and ¹ Department of Anatomy and Physiology, Swedish University of Agricultural Sciences, Box 7045, 750 07 Uppsala, Sweden

Correspondence should be addressed to C Berg; Email: Cecilia.Berg{at}ebc.uu.se

Eggshell thinning among wild birds has been an environmental concern for almost half a century. Although the mechanisms for contaminant-induced eggshell thinning are not fully understood, it is generally conceived to originate from exposure of the laying adult female. Here we show that eggshell thinning in the domestic hen is induced by embryonic exposure to the synthetic oestrogen ethynyloestradiol. Previously we reported that exposure of quail embryos to ethynyloestradiol caused histological changes and disrupted localization of carbonic anhydrase in the shell gland in the adult birds, implying a functional disturbance in the shell gland. The objective of this study was to examine whether in ovo exposure to ethynyloestradiol can affect eggshell formation and quality in the domestic hen. When examined at 32 weeks of age, hens exposed to ethynyloestradiol in ovo (20 ng/g egg) produced eggs with thinner eggshells and reduced strength (measured as resistance to deformation) compared with the controls. These changes remained 14 weeks later, confirming a persistent lesion. Ethynyloestradiol also caused a decrease in the number of shell gland capillaries and in the frequency of shell gland capillaries with carbonic anhydrase activity. These data suggested that a disrupted carbonic anhydrase expression was involved in the mechanism for the oestrogen-induced eggshell thinning found in this study. The results support our hypothesis that eggshell thinning in avian wildlife can result from a structural and functional malformation in the shell gland, induced by xeno-oestrogen exposure during embryonic development.

This article has been cited by other articles:

				T. Utsumi and Y. Yoshimura Sensitive embryonic endpoints with in ovo treatment for detecting androgenic and anti-androgenic effects of chemicals in Japanese quail (Coturnix japonica) Poult. Sci., May 1, 2009; 88(5): 1052 - 1059. [Abstract] [Full Text] [PDF]