Pathological alterations in response to water soluble fraction of Iranian crude oil in gill of yellow fin sea bream Acanthopagrus latus (Houttuyn, 1782)

Water soluble fraction (WSF) of crude oil can pollute water and cause histopathological alterations in fishes. Therefore, sea water pollution with crude oil could detrimentally impact the fish health. The aim of the present study was to evaluate the effect of different concentrations of WSF on gills of yellow fin sea bream. The fish were exposed to 0% (control), 2%, 4%, 8% and 16% of WSF for a period of 21-days. The histopathological alterations were examined in four categories of circulatory, degenerative, proliferative and inflammatory. Inclusion of WSF at concentrations of 4%, 8% and 16% led to significant elevation of total petroleum hydrocarbon concentration in water (p<0.05). In the 8% group, the changes in histopathological lesions observed from day 16 compared with control group (p<0.05). In the 16% group, increasing histopathological lesions was observed from day 8 compared with the control group (p<0.05). However, no significant increase in histopathological lesions was observed in fish exposed to 2% and 4% WSF as compared with the control group (p>0.05). In conclusion, the findings of the present study indicated concentration and period of exposure as determinant factors influencing the level of alterations in gills histopathological lesions following exposure to WSF in yellow fin sea bream.