Assessment of imidacloprid induced genotoxicity in Pethia conchonius (Rosy barb), a common freshwater fish of India

Abstract

Imidacloprid is one of the highly efficient, globally used neonicotinoid groups of insecticides. The indiscriminate use of imidacloprid is contaminating large water bodies affecting not only the target organisms but also non-target organisms including fish. The present study aimed to assess the extent of nuclear DNA damage by imidacloprid in Pethia conchonius a freshwater fish in India using comet and micronucleus assays. The LC₅₀ value of imidacloprid was estimated to be 227.33 mg L⁻¹. Based on the LC₅₀-96 h value, three sub-lethal concentrations of imidacloprid, SLC I −18.94 mg L⁻¹, SLC II −28.41 mg L⁻¹ and SLC III −56.83 mg L⁻¹ were used to detect its genotoxic effect at DNA and cellular level. The imidacloprid exposed fishes exhibited higher DNA damage and nuclear abnormalities (p < 0.05) than the control. The %head DNA, %tail DNA, tail length and the frequency of micronuclei with other nuclear abnormalities like blebbed and notched nuclei were significantly higher than the control in a time and concentration-dependent manner. The DNA damage parameters such as %head DNA (29.107 ± 1.843), %tail DNA (70.893 ± 1.843), tail length (361.431 ± 8.455) micronucleus (1.300 ± 0.019), notched (0.844 ± 0.011) and blebbed (0.811 ± 0.011) nuclei were found to be highest for SLC III (56.83 mg L⁻¹) at 96 h. The findings indicate that IMI is highly genotoxic in fish and other vertebrates leading to mutagenic/clastogenic effects. The study will be helpful in optimization of the imidacloprid use.

Keywords:

• Imidacloprid
• Pethia conchonius
• comet assay
• micronucleus assay

Acknowledgement

The authors are thankful to the Head, Department of Zoology, University of North Bengal for providing a Departmental Central instrument facility under the support of the Fund for Improvement of Science and Technology Infrastructure Program (FIST), Department of Science and Technology, New Delhi, India, and the funding agency National fellowship for Schedule Cast, University Grants Commission, New Delhi. The authors are also grateful to the people who supported this research.

Ethical approval

The present investigation has been approved by the Institutional Animal Ethics Committee of the University of North Bengal vide ref No. IAEC/NBU/2022/30 dated 23.09.2022 (Proposal No. 12).

Authors contributions

There are no conflicts of interest among the authors. The original research was conducted by D. Dutta and A. Ray. Statistical analysis was conducted by D. Dutta and B. Ghosh. The manuscript was written by D. Dutta. M. Bahadur edited and reviewed the mss as supervisor of the Genetics and Molecular Biology Laboratory, Department of Zoology, University of North Bengal. This work was partially supported by UGC. The data generated during this study are available from the corresponding author upon request. The authors have no financial or non-financial interests to disclose.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets generated and analyzed during the study are available from the corresponding author upon reasonable request.

Additional information

Funding

This work was partially supported by UGC-National Fellowship for Schedule Cast Vide Ref No. F. 82–1/2018 (SA-III).