Effects of Sublethal Concentrations of Diazinon on Total Protein in Tilapia Fish (Oreochromis Niloticus)

Abstract

This study assessed the influence of organo-phosphorus (OP) Diazinon pesticide on adult tilapia fish (Oreochromis niloticus) in a semi static renewal bioassay for 30 days. Adult fish were acclimatized to laboratory conditions for 7days and then exposed to varying sub-lethal concentrations of diazinon (1.0, 2.5, 5.0, 7.5 and 10.0 mg/l) for 30 days and compared with control (untreated). Total protein was determined in plasma, muscle, gills, liver and kidney. The water quality used for the study showed pH 7.05, dissolved oxygen 6.7 mg/l, temperature 26.0 0 C, alkalinity 16.25 mg/l, conductivity 106.12ps/cm and turbidity 0.46 NTU. The 96h LC50 of diazinon was 7.65mg/l. At various concentration of diazinon, fish showed uncoordinated behaviour such as somersaulting, convulsion and erratic swimming. The levels of total protein in plasma was significantly lower (P<0.05) in all test concentrations in comparison with the control; but no concentration-dependent among the various concentration of diazinon was observed. Conversely, protein concentrations in muscle, liver, gills and kidney decreased with increased concentration of diazinon (P<0.05). It is concluded that protein concentrations in muscle, gill, liver and kidney are useful biomarkers of sub-lethal effects of diazinon in Oreochromis niloticus.