THE COMET ASSAY USING RAINBOW TROUT (Oncorhynchus mykiss) FOR THE DETECTION OF NUTRIENT POLLUTION GENERATED FROM OVERFED FISH FARMS IN THE ESEN STREAM

摘要

In this study, three different sites in the Esen Stream (namely, Site 1 that was used as the control group, Site 2 that had the highest pollution degree, and Site 3), were assayed for genotoxicity induced by nutrient pollution using the Comet assay in the peripheral blood of rainbow trout (Oncorhynchus mykiss). At each site, blood was taken from six samples to investigate the potential damage in fish blood lymphocytes with Comet assay. The results revealed that both DNA tail % and tail moment (pm) significantly increased in Site 2 and Site 3 compared to Site 1. Site 2 had the highest level of water parameters (such as suspended solids, total phosphates, ammonium and nitrate-nitrogen, and chemical oxygen demand) and showed the highest genotoxic damage for both DNA tail % and tail moment. Oxidative DNA damage was also investigated with bacterial enzymes, namely, Endo III and FPG. According to the results, oxidative damage was higher in purines than pyrimidines for the studied sites. These results confirm the usefulness of the Comet assay with fish blood lymphocytes as an in vivo model for eco-genotoxicological studies.