Effect of Cd on serum osmolality, ion levels and hematological parameters of tilapia (Oreochromis niloticus) at different salinity levels

ABSTRACT

Effects of cadmium on serum osmolality, ion levels and hematological parameters of tilapia (Orechromis niloticus) were evaluated at different salinities. Serum osmolalities (SOs) in fish unexposed to Cd (0 mg l⁻¹) and exposed to 2.5 mg Cd l⁻¹ were not significantly different at salinities of 0, 5 and 10 g l⁻¹, while at 15 g l⁻¹, SO was significantly higher than at 0, 5 and 10 g l⁻¹. Levels of Na⁺ and Cl⁻ in serum at salinities of 5, 10 and 15 g l⁻¹ were not significantly different; but were significantly higher than those at 0 g l⁻¹ with and without Cd. In media without Cd, the lowest level of K⁺ in serum occurred at 15 g l⁻¹ salinity, whereas levels of K⁺ at 0, 5 and 10 g l⁻¹ were not significantly different. The levels of K⁺ in Cd-exposed fish at all salinities were not significantly different. At 0 g l⁻¹ salinity, hemoglobin, red blood cells, and hematocrit in Cd-exposed fish were significantly lower than controls. At salinities of 5, 10 and 15 g l⁻¹, levels in control and Cd-exposed fish were not significantly different indicating that higher salinity prevented Cd-induced osmotic imbalance and hematological alterations.

KEYWORDS:

• Cadmium
• Oreochromis niloticus
• salinity
• osmoregulation
• serum ions
• hematology

Acknowledgments

This research was supported by the research mandate of Universitas Airlangga. The authors would like to thank Mr. Setiyanto for technical assistance during the experiment.

Disclosure statement

No potential conflict of interest was reported by the authors.