Evaluation of gill tissue structure in yellowfin seabream Acanthopagrus latus during short time exposure to phenanthrene

The present study aimed to investigate the gill tissue changes in yellowfin seabream (Acanthopagrus latus) exposed to different concentrations of phenanthrene (Phe) during 2 weeks. In this regards, fish were intraperitoneally injected with 2, 20, 40 and 70 mg/kg-bw of Phe and were kept under laboratory conditions for 14 days. Tissue samples were taken from the gill of 100 A. latus (5sample/group/day) at days 1,3, 7, and 14 and tissue slides were prepared according the routine histological methods. Briefly, the samples were fixed in formalin buffer solution for 48 h, dehydrated in a graded series of ethanol, and embedded in paraffin. Five micrometer thick sections were stained in H&E for microscopic examination. Also, the degree of tissue changes (DTC) was calculated to evaluate the organ heath. Based on the results, the most tissue changes in the gill of fish treated with phenanthrene included lamellar cells hyperplasia, lamellar fusion, and epithelial lifting. The highest amount of DTC was measured in fish treated with 70mg/kg Phe at day 7. The DTC means were varied from moderate to severe for gills in this group, indicating that, phe with the concentration of 70 mg/kg could affect the fish health. The least DTC means of fish exposed to 2 mg/kg demonstrated the fish resistance to this concentration. The results suggest that there is close relation between amounts of pathological alterations and the pollutant concentration.