Levamisole incorporation in fish feed – Ensuring the medication dose and avoidance of leaching into the water

Abstract

Levamisole, an anthelmintic and immunostimulant drug, has been studied as a promising alternative for aquaculture use. While oral administration through feeding is the main route of administration in fish farming, no studies evaluating methods of levamisole incorporation into the feed have been reported so far. Therefore, this study aimed to evaluate potential procedures for levamisole incorporation in extruded fish feed using ethyl cellulose, gelatin, or vegetable oil, to avoid drug leaching to the water during the animal’s medication. A suitable LC-MS/MS method was optimized (full factorial design), validated, and applied to evaluate the efficiency of the process, the homogeneity of the drug concentration, and the leaching rate. The method has been demonstrated to be selective, precise (RSD < 4.9%), accurate (recovery > 98.4%), and linear (r > 0.99, 125–750 mg kg⁻¹). The incorporation procedures using the three coating agents showed high incorporation efficiency (70%) and a homogeneous drug concentration among the extruded feed pellets. A low levamisole leaching rate was verified in the feed prepared using the ethyl cellulose coating procedure (4.3% after 15 min of immersion in the water). On the other hand, fish feed coated with gelatin and oil resulted in a high leaching rate (30–35% after 15 min). Thus, this study shows that coating ethyl cellulose may be a promising procedure for levamisole incorporation in fish feed and with the potential to enhance its use in animal production while reducing environmental contamination.

Keywords:

• Aquaculture
• fish farming
• veterinary drug
• medicated feed
• LC-MS/MS

Acknowledgments

The authors are grateful to the School of Pharmaceutical Sciences of Ribeirao Preto, the University of Sao Paulo (FCFRP-USP). The authors would like to thank the São Paulo Research Foundation (FAPESP), the Coordination for the Improvement of Higher Education Personnel (CAPES), and the International Atomic Energy Agency (IAEA) for the financial support.

Disclosure statement

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.

Additional information

Funding

This study was supported by São Paulo Research Foundation (Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP: grants numbers 21/03294-1, 21/11996-6, 21/08152-0); Coordination for the Improvement of Higher Education Personnel (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES: financial code 001); and International Atomic Energy Agency (IAEA Coordinated Research Project D52043, Research Contract No. 24019).