Effects of potential xenoestrogens (DEHP, nonylphenol and PCB) on sexual differentiation in juvenile Atlantic salmon (Salmo salar)

Abstract

The effects of 17β-estradiol and potential xenoestrogens were investigated on Atlantic salmon (Salmo salar). Juvenile salmon fed diets containing 15 and 30 mg 17β-estradiol kg⁻¹ food for 4 weeks after yolk-sac resorption differentiated into 88 and 100% phenotypic females, respectively. The reference group, fed uncontaminated food, consisted of 49% females. A significant overrepresentation of phenotypic females (64%) was recorded in the group fed 1500 mg di-2-ethylhexyl phthalate kg⁻¹ food. Atlantic salmon fed diets contaminated with nonylphenol showed no differences in sex ratios compared with the control group. A significantly increased liver somatic index was detected for groups exposed to diets contaminated with 15 and 30 mg 17β-estradiol, 300 mg nonylphenol or 1500 mg di-2-ethylhexyl phthalate kg⁻¹ food. Intraperitoneal injections of nonylphenol, di-2-ethylhexyl phthalate, or polychlorinated biphenyls 58, 104, 112 and 188 did not induce synthesis of vitellogenin which is considered to be a hallmark for estrogenic activity in in vivo testing. Therefore, in vivo assays, that is, intraperitoneal injection, can not always predict how endocrine processes in organisms are affected by pollutants.