Acute hematological toxicity of ivermectin to juvenile Clarias gariepinus

Acute behavioral and hematological toxicity of ivermectin to C. gariepinus juveniles were assessed under static conditions at concentrations of 9 to 25 mu g L-1 for up to 4 days. Juveniles were highly sensitive to ivermectin, with an LC50 of 15 mu g L-1, culminating in spasms and paralysis. The hematological responses of packed cell volume, hemoglobin and red blood cell count decreased when compared to the control while the white blood cell count showed a biphasic trend. The mean corpuscular volume and mean corpuscular hemoglobin showed a mixed trend, while mean corpuscular hemoglobin concentration increased with increase in the concentration of the drug. Lymphocytes and neutrophils were also significantly (p < .05) increased. Ivermectin did not elicit any significant changes in monocytes, basophils and eosinophils. The observed changes confirm that ivermectin negatively affected the health of the fish. Therefore, real-time monitoring for early warning is recommended.