Haemotoxic Assessment of Differential Leucocyte Counts (DLC) in Fresh Water Teleost, Heteropneustes fossilis Exposed to Lead

BACKGROUND, in recent years, fish blood is being used for assessing the health and general condition of the fish subject to changing environmental conditions due to heavy metals which are regularly released by anthropogenic activities. The present experiment was set up to assess the effects of the heavy metal, lead (Pb) on the Differential Leucocyte Counts (DLC) of fresh water teleost Heteropneustes fossilis. Results.The acclimatized fish were exposed to different concentrations of lead [2.25ppm (Group B), 2.65ppm (Group C), and 2.85ppm (Group D)] and the values were compared with the control (Group A). The time interval of examination was 7, 14, 21 and 28 days post exposure. DLC showed changes in small lymphocytes resulting in the fall of 41% to 31% at 2.65 ppm of Pb during 28 days of exposure period. The large lymphocyte counts also decreased from normal value of 39% to 27% at maximum concentration and maximum exposure period (2.85 ppm Pb; 28 days). The neutrophils increased from normal counts (14%) to maximum (26%) at 2.65 ppm of Pb during 28 days exposure period. The monocyte counts increased from normal counts of 3% to 7% during 7 and 28 days exposure period at 2.65 ppm of Pb. The counts of eosinophils increased against the toxicity of lead from 2% to 6% at maximum concentration (2.85 ppm) during 14 and 28 days exposure period. Basophils increased from normal range (1%) to 3% at 2.65 ppm of Pb at 28 days exposure period. Conclusion, our results indicated that exposure to lead results in altered leucocyte counts