Effect of phosalone on haematological indices in the tilapia, Oreochromis mossambicus

Abstract

The aim of this study was to assess the effect of phosalone on the tilapia, Oreochromis mossambicus. The effect was assessed on the basis of the results of acute toxicity tests and comparison of results of haematological examination of a control and an experimental group exposed to phosalone. The 96 h LC_{50} is the basic value in the acute toxicity test and it was 0.26 mg/L for phosalone against the test fish. Haematological profile of the healthy fish was carried out with 2 sublethal concentrations, viz 0.0325 mg/L (1/8) and 0.065 mg/L (1/4) of phosalone. The experiment was performed semi-statically with a group of 10 fish in 10 experimental aquaria, 2 control aquaria, and 4 aquaria each with different concentrations. The results showed that phosalone had some effect on the haematological parameters of tilapia. It was determined that the total RBCs, WBCs, haemoglobin content, and haematocrit value significantly decreased (P < 0.001). The percentages of erythrocyte sedimentation rate, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration showed an increasing trend with respect to the increase in exposure period in both sublethal concentrations. ANOVA showed that the pesticide concentrations had more influence than the duration of exposure in all cases (P < 0.001).