Detection of aflatoxin-producing fungi isolated from Nile tilapia and fish feed

Authors

  • Hams M.A. Mohamed Department of Microbiology, Faculty of Veterinary Medicine, South Valley University, 83523-Qena, Egypt
  • Walaa F.A. Emeish Department of Fish Diseases and Management, Faculty of Veterinary Medicine, South Valley University, 83523-Qena, Egypt
  • Albert Braeuning Department of Food Safety, German Federal Institute for Risk Assessment, 10589-Berlin, Germany
  • Seddik Hammad Department of Forensic Medicine and Veterinary Toxicology, Faculty of Veterinary Medicine, South Valley University, 83523-Qena, Egypt; Molecular Hepatology Section, Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany

DOI:

https://doi.org/10.17179/excli2017-960

Keywords:

Oreochromus niloticus, A. flavus, aflatoxins, clove oil

Abstract

Contamination of fish by fungi and their mycotoxins poses major health concerns to human and animals. Therefore, our study was aimed to investigate Aspergillus flavus (A. flavus) infections and the levels of aflatoxins in Nile tilapia, Oreochromis niloticus (O. niloticus), and fish feed. Samples from O. niloticus and fish feed (n=25 for each) were randomly collected from private fish farms at Qena province, Egypt, during the winter season. Different Aspergillus spp. were detected in 60 % and 64 % of O. niloticus and fish feed, respectively. HPLC-based analysis revealed aflatoxin-producing activity in 75 % and 83 % of A. flavus isolates from fish and fish feed, respectively. While 96 % of O. niloticus muscles and fish feed samples were contaminated with aflatoxins, the detected levels were below the permissible limits, i.e. 20 µg/kg. Moreover, experimental infection with toxicogenic A. flavus isolates was conducted to evaluate their pathogenicity in O. niloticus. Expectedly, experimental infections of O. niloticus with A. flavus were associated with several clinical symptoms reported in naturally infected fish, e.g. yellow coloration with skin ulceration, hemorrhagic ulcerative patches on gills and skin, corneal opacity, fin rot and abdominal distention. Furthermore, aflatoxicogenic A. flavus isolates from fish were sensitive to herbal clove oil. Even though the measured levels of aflatoxin were below permissible limits, effort should be placed on further reduction of exposure to genotoxic and carcinogenic mycotoxins.

Published

2017-12-13

How to Cite

Mohamed, H. M., Emeish, W. F., Braeuning, A., & Hammad, S. (2017). Detection of aflatoxin-producing fungi isolated from Nile tilapia and fish feed. EXCLI Journal, 16, 1308–1318. https://doi.org/10.17179/excli2017-960

Issue

Section

Original articles