TO STUDY THE EFFECT OF HEAVY METALS ON VARIOUS TISSUES OF TILAPIA (Oreochromis mossambicus) AT MOLECULAR LEVEL

This study was conducted to assess the effect of metal pollutants at molecular level in selected fish tissues. Effect of sub lethal concentrations of zinc and lead on total protein and nucleic acid content in gills and liver of Tilapia was determined. There was an increase in protein content in the gills by 16.25% and 11.25%, while in liver tissue a decrease was seen by 33.3% and 11.85% when fish were exposed to sub-lethal concentrations of zinc chloride and lead nitrate. RNA content increased in gill by 38.79% and 29.3%, while DNA content increased by 13.66% and 39.33%. There was a decrease in both RNA and DNA content in the liver. The results show that heavy metal like zinc and lead cause changes at molecular level in the tissues of fishes.