New investigations on the endocrine disruption effects in the mediterranean population of swordfish (Xiphias gladius)

Since 1999 the Department of Environmental Science at Siena University has been involved in research into the ecotoxicological effects of Endocrine Disrupting Compounds (EDCs) in a Mediterranean population of swordfish (Xiphias gladius). Using sensitive biomarkers such as Vitellogenin (VTG), Zona Radiata Protein (ZRP), sex hormone pathways and CYP1A activities (EROD, BPMO), exposure and effects of anthropogenic chemical have been studied in more than 200 Mediterranean specimens. VTG and ZRP were found to be induced in 35% adult male specimens. These fish showed higher levels of both proteins and 17β-estradiol than mean levels in males from reference sites, suggesting high exposure to xenoestrogens in the Mediterranean Sea. A role of Organochlorines in this induction phenomenon is suggested by statistically significant correlations found between VTG and ZRP levels in males and levels of hexachlorobenzene (HCB) in gonads (p<0.05), plasma 17β-estradiol and polychlorobiphenyl (PCB) in gonads (p<0.05), ZRP and pp’DDE in liver (p<0.06). These results indicate that Mediaterranean swordfish could be subject to reproductive alterations. In order to better understanding the present results, alterations in swordfish liver and gonads (testis and ovary) will be investigated. Histopathological studies including the immunoistochemical detection of VTG, ZRP and CYP1A will be performed. Moreover, the mRNA contents of the aromatase and CYP1A genes in swordfish will be measured. All results obtained will be correlated with the quantitative analysis of TCDD, PCBs and organochlorine pesticides in tissues.