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Licentiate thesis, 2011

Effects of octylphenol on sexual development and reproduction in zebrafish

Mahgiubi Shaima A M


Anthropogenic chemicals released into the aquatic environment can disrupt the normal function(s) of an organism's endocrine system and thereby adversely affect reproduction and development. This has led to the development of robust fish tests to detect and assess endocrine active chemicals. This thesis investigated developmental and reproductive effects of exposure to octylphenol (OP) in zebrafish. Zebrafish were exposed to OP in a Fish Sexual Development Test (FSDT) to investigate effects on sexual development. The main endpoints were vitellogenin induction and gonad development, including sex ratios. Zebrafish were also exposed to OP in a Fish Full Life Cycle test (FFLC) and a Fish Short Term Reproduction Assay (FSTRA) to investigate effects on different reproductive processes; i.e. gonad development, sexual phenotype and reproductive performance. Exposures to OP resulted in shifts in sex ratios, suppression in ovarian development, impairment in reproduction and reduction in growth, whereas no effects on VTG levels were observed. Conclusively, both the FSDT and FFLC test, but not the FSTRA, were sensitive tests for detection of endocrine-related effects of the weak estrogen OP. This thesis shows that OP, acting as a weak estrogen, has a negative impact on sexual development and maturation as well as reproduction in zebrafish.


zebrafish; sex ratio; gonad maturation; vitellogenin; reproductive performance; octylphenol

Published in

Report (Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences)
2011, number: 5
ISBN: 978-91-576-9053-1
Publisher: Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences