Exposure to cobalt chloride alters hemato-biochemical indices and erythrocyte morphology in stinging catfish, Heteropneustes fossilis

Higher amounts of cobalt chloride (CoCl2) released by industries are regarded as environmental pollutants. The goal of the current investigation was to assess the acute toxicity of CoCl₂ from its effects on erythrocyte morphology and hemato-biochemical indicators in stinging catfish, Heteropneustes fossilis. The fish were subjected to CoCl₂ at five different concentrations of 0, 50, 100, 200, and 300 mg L^−l, which were referred to as control, CC50, CC100, CC200, and CC300, respectively. Red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), platelet counts, white blood cell (WBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), lymphocytes, granulocytes, serum protein, and blood glucose level were among the hemato-biochemical parameters of stinging catfish that were measured following a 96 h exposure period. Additionally, erythrocytic nuclear abnormalities (ENA) and erythrocytic cellular abnormalities (ECA) were evaluated in the experimental fish. As the quantity of CoCl₂ increased, there were notable reductions in RBC, Hb, Hct, WBC, platelet counts, MCH, MCV, MCHC, lymphocytes, granulocytes, serum protein, and blood glucose levels compared to the control. When the CoCl₂ concentration increased, the frequencies of ECA and ENA also increased significantly (P < 0.05). This work demonstrated the significant toxicity of high CoCl₂ concentrations caused alterations in hemato-biochemical indices and deformities in the erythrocytes of stinging catfish. Thus, it is imperative to take all necessary corrective action to guarantee that the amount of CoCl₂ in the aquatic environment stays below permissible limits.