Protective action of zinc against lead poisoning in tilapia Oreochromis niloticus

Abstract

The accumulation of lead (Pb) in tilapias Oreochromis niloticus, acclimatized in cement tanks, and fed once a day with pellets of commercial food with lead nitrate, was investigated by square wave anodic stripping voltammetry (SWV). The head (including head bones, proteins, and brain) was the main target of lead uptake by tilapias, with a small amount in muscle tissue. A high concentration of Pb was found in feces which indicated low absorption by the organism when fed with high Pb concentration. The protective effects of zinc (Zn) against the Pb poisoning, the accumulation of Pb in the heads of the fishes of 107.8 ± 3.1 mg kg⁻¹ and in the viscera of 57.1 ± 2.9 mg kg⁻¹ with consequent decrease of calcium (Ca) concentration, were observed. In spite of the experimental time of 16 months and higher Pb concentration in the dietary food of 320 mg kg⁻¹, no death of tilapias was observed due to the protective action of Zn.

Keywords:

• Voltammetry
• tilapia
• metals
• bioaccumulation
• brain

Acknowledgments

A.T.P. thanks the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES-Brazil) for a doctorate fellowship, L.D.S. and J.N. are grateful to the Conselho Nacional de Desenvolvimento Ciêntífico e Tecnológico (CNPq-Brazil) and Fundação Araucaria-PR (Brazil) for financial support.

Notes

*In memoriam.

Additional information

Notes on contributors

Jorge Nozaki*

*In memoriam.