Dietary supplementation of garlic, propolis, and wakame improves recuperation in cadmium exposed Japanese medaka fish (Oryzias latipes)

Abstract

Cadmium (Cd) toxic effects can overwhelm endogenous antioxidants and affect recuperation in fish. Thus, this study assessed antioxidative properties and ameliorating potentials of dietary supplemented garlic (D1), propolis (D2), and wakame (D3) on i) Cd bioconcentration, and ii) Cd induced toxicity during recuperation in Cd exposed Japanese medaka. In a 21-day exposure, control (0.0 mg Cd/L in water—C1) or Cd-treatment (0.3 mg Cd/L in water—T1) fish were fed medaka diets. Surviving fish in T1 were further depurated for 21-days and fed D1, D2, D3, or medaka diet (C2). Gill, liver, and muscle tissues were assessed weekly for Cd bioconcentration, metallothionein, (MT), superoxide dismutase (SOD), total glutathione (GSH), and lipid peroxidation (LPO). Results showed reduced antioxidant activity by significantly increasing tissue Cd and LPO, and significantly reducing SOD activity and GSH content in gill and muscle upon Cd exposure. In contrast, D1, D2, and D3 diets significantly reduced tissue Cd and LPO, while increasing contents of MT and GSH, and SOD activity, significantly. Other condition indices in D1, D2 and D3 groups were also significantly higher than those in C2 groups. In conclusion, dietary supplementation significantly increased recuperation and tissue functions in fish, in the order D1 > D2 > D3> C2.

Keywords:

• Amelioration
• antioxidants
• depuration
• recuperation
• heavy metal

Authors’ contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Ujeh HO. The first draft of the manuscript was written by Ujeh HO and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Conflicts of interest/competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Ethics approval

All fish experiments were carried out in conformity to the rules approved by the Institutional Animal Care and Use Committee of Hokkaido University, Japan. Fish handling and cadmium exposure were in accordance with the OECD guidelines for testing of chemicals (305 Draft: 1.12.2011).