DIFFERENT TOXIC SENSITIVITY BETWEEN EMBRYONIC FLOUNDER (PARALICHTHYS OLIVACEUS) AND SPOTTED SEA BASS (LATEOLABRAX MACULATES) EXPOSED TO IRANIAN HEAVY CRUDE OIL MALFORMATION AND CYP1A EXPRESSION

Abstract

M/V Hebei sprit oil spill (HSOS) which is considered as a one of the largest tanker spills of recent years, comparable to the Prestige oil spill in 2002 and Tasman Spirit in 2003. In the study, to clarify the effects of spilled oil on resident fish development, spotted bass (Lateolabrax maculates) and olive flounder (Paralichthys olivaceus) embryos (48 hr post-fertilization) were exposed to oiled gravel effluent of Iranian Heavy crude oil (IHCO) oil for 48 hr. Embryos were manually dechorionated and observed by a stereomicroscope and a compound microscope. Embryos were fixed in 4% phosphate-buffered paraformaldehyde and stained for CYP1A and myosin heavy chain. After 24 hr, several complex effects, including the pericardium edema and tail mutant were observed in both of embryos after the IHCO exposure. The distribution of CYP1A in embryo was assessed by immunofluorescence. CYP1A immunofluorescence activity was high significantly in the endothelium of head, epidermis and cardium and a significant induction of CYP1A mRNA was observed in both of embryos after the oil exposure. The extent of tail abnormalities and edema in olive flounder were stronger than those of spotted bass in oil exposed groups. But the levels of CYP1A expression were lower than those of spotted bass. Our results confirm that the HSOS caused significant damage to resident fish embryos and different toxic sensitivity weresident fish development, spotted bass (Lateolabrax maculates) and olive flounder (Paralichthys olivaceus) embryos (48 hr post-fertilization) were exposed to oiled gravel effluent of Iranian Heavy crude oil (IHCO) oil for 48 hr. Embryos were manually dechorionated and observed by a stereomicroscope and a compound microscope. Embryos were fixed in 4% phosphate-buffered paraformaldehyde and stained for CYP1A and myosin heavy chain. After 24 hr, several complex effects, including the pericardium edema and tail mutant were observed in both of embryos after the IHCO exposure. The distribution of CYP1A in embryo was assessed by immunofluorescence. CYP1A immunofluorescence activity was high significantly in the endothelium of head, epidermis and cardium and a significant induction of CYP1A mRNA was observed in both of embryos after the oil exposure. The extent of tail abnormalities and edema in olive flounder were stronger than those of spotted bass in oil exposed groups. But the levels of CYP1A expression were lower than those of spotted bass.