Effects of Sub-lethal Lead Nitrate and Copper Sulfate Concentrations on Hematological Parameters During Long-term Exposure in Nile tilapia (Oreochromis niloticus)

Abstract

Nile tilapia (<em>Oreochromis niloticus</em>) weighing 51.66 ± 2.42 g were exposed to 0%, 20%, 40%, and 60% of LC₅₀ to either lead nitrate (Pb(NO₃)₂) or copper sulfate (CuSO₄) for 30 days. The Pb(NO₃)₂ and CuSO₄ concentrations employed in the treatments of this study were 8.8, 17.6, and 26.4 mg/L and 2.57, 5.14, and 7.71 mg/l, respectively, and multiple hematological variables were evaluated. The red blood cell (RBC) count for the control group was 2.41 ± 0.13 while those of the treatment groups exposed to 8.8, 17.6, and 26.4 mg/L of Pb(NO₃)₂ were 2.21 ± 0.10, 1.94 ± 0.16, and 1.36 ± 0.10 × 10⁶/µl, respectively, at the end of the study. Similarly, the hemoglobin (Hb), hematocrit (Hct), mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC), and platelet (PLT( levels significantly decreased as the Pb(NO₃)₂ concentration increased (p < 0.05), while white blood cell (WBC) and mean cell volume (MCV) levels significantly increased. However, results of fish exposed to CuSO₄, showed decrease in the levels of RBC, Hb, Hct, WBC, and PLT when the concentration of CuSO₄increased, while the MCHC, MCH, and MCV levels significantly increased.