Long-term estrogen exposure of whitefish Coregonus lavaretus induces intersex but not Lake Thun-typical gonad malformations

Kipfer, S.; Segner, Helmut; Wenger, M.; Wahli, Thomas; Bernet, Daniel (2009). Long-term estrogen exposure of whitefish Coregonus lavaretus induces intersex but not Lake Thun-typical gonad malformations. Diseases of aquatic organisms, 84(1), pp. 43-56. Oldendorf (Luhe) (D): Inter-Research 10.3354/dao02031

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A high prevalence of gonad morphological variations has been observed in whitefish Coregonus lavaretus from Lake Thun (Switzerland). To clarify the role of endocrine disruption as a possible cause of the gonad alterations, whitefish were reared in a long-term laboratory experiment under exposure to 17 beta-estradiol (E2). Fish were fed from first-feeding until 3 yr of age at a daily rate of 0 (control), 0.5 or 50 microg E2 kg(-1) fish. E2 exposure resulted in a time- and concentration-dependent increase of prevalence and intensity of intersex gonads, i.e. gonads that macroscopically appeared as either testis or ovary but microscopically contained both male and female germ cells. Four types of intersex could be distinguished: Types 1 and 2 were composed of mainly male tissue, with Type 1 containing single oocytes and Type 2 displaying an ovary-like lamellar structure of the tissue. In Type 3, an increased percentage of the tissue was occupied by female germ cells, while in Type 4, the majority of the gonad tissue consisted of female germ cells. Chronic E2 exposure additionally resulted in a concentration-dependent shift of the sex ratio towards females, a reduced condition factor, retarded gonad growth together with delayed maturation of germ cells, and elevated levels of hepatic vitellogenin mRNA. However, Lake Thun-typical alterations of gonad morphology were not induced by chronic E2 exposure. The results provide evidence that estrogen-active compounds unlikely play a role in the etiology of gonad malformations in Lake Thun whitefish.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Center for Fish and Wildlife Health (FIWI)

UniBE Contributor:

Segner, Helmut; Wahli, Thomas and Bernet, Daniel

Subjects:

600 Technology > 630 Agriculture

ISSN:

0177-5103

Publisher:

Inter-Research

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 15:25

Last Modified:

21 Jul 2014 10:16

Publisher DOI:

10.3354/dao02031

Web of Science ID:

000264794600006

URI:

https://boris.unibe.ch/id/eprint/38354 (FactScience: 221208)

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