Fish blood is being used for assessing the health of the fish to changing environmental conditions due to heavy metals which are regularly released by anthropogenic activities. This study assesses the effects of lead (Pb) on the Differential Leucocyte Counts (DLC) of fresh water teleost Heteropneustes fossilis.
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 of 39% to 27% at maximum concentration and maximum exposure period (2.85 ppm Pb; 28 days). The neutrophils increased (14%) to maximum (26%) at 2.65 ppm of Pb during 28 days exposure period. The monocyte counts increased 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 (1%) to 3% at 2.65 ppm of Pb at 28 days exposure period.
Our studies indicated that exposure to lead results in altered leucocyte counts.