Endocrine disrupting effects of 4-nonylphenol on plasma vitellogenin, reproductive system and histology in koi carp (Cyprinus carpio)

This study aimed to assess the effect of 4-nonylphenol (4-NP), a ubiquitous aquatic micro-chemical pollutant substance on some on some reproductive parameters and histology in koi carp. Fish were intraperitoneally subjected to ascending doses of 4-NP at 10, 50 and 100 mu g/g body weight (BW) on days 7, 14 and 21 after the initiation of the experiment. Also, one group was treated with 17 beta-estradiol (E2) at 2 mu g/g BW, positive control group (C2) received the vehicle (50 mu L of coconut oil + 50 mu L Ethanol) per fish and a negative control group (C1) was considered without injection. The results showed that 4-NP induced significantly an increase in E2, progesterone, and plasma vitellogenin at 50 mu g/g in both male and female, while level of testosterone significantly decreased in the treated fish compared to control fish (P < 0.05). Conversely, the levels of these parameters at the higher concentration of 4-NP (100 mu g/g) were significantly reduced compared to control one (P < 0.05). Also, some sever histopathological changes were observed in ovary, testicular and liver of treated fish, reflecting fish sensitivity to 4-NP at higher doses. This study showed that 4-NP has an estrogenic potency in the sexual development, hepatotoxicity and gonado-toxicity of koi carp.