Isolation of mycotoxin-producing fungi from fishes growing in aquacultures

Abstract

Contamination of fishes with mycotoxin-producing fungi has a negative impact on the public health. The main goal of this study was to emulate contamination of fishes grown in aquacultures with potentially mycotoxin-producing microfungi. Five fishes including Nile tilapia, African catfish, Tilapia zilli, Bony bream and Thinlip Mullet species were collected from different aquacultures distributed in Delta region, Egypt. From each fish species, at least 10 random samples were subjected for the fungal analysis. The most common isolated fungi were tested for their potentiality to produce mycotoxins in vitro. Detection of the mycotoxins was carried out by thin layer chromatography compared to mycotoxin standards. Results showed that 21 fungal species were isolated from five fish species. The highest number of species (15) was isolated from African catfish, but the lowest number (6 species) was isolated from Bony bream. The most common fungal species isolated from these fish species were; Paecilomyces lilacinus, P. variotii and Phoma herbarum. Mycotoxin producing fungi including Aspergillus flavus, A. clavatus, A. ochraceous, A. parasiticus, A. sydowii, A. terreus, A. versicolor Penicillium chrysogenum and Trichoderma viride were recovered. Production of aflatoxin Bl, B2 and Gl, strigmatocystin ochratoxin and T2-toxin by these fungal species was approved. Most species were found to produce aflatoxin and stregmatocystin while ochratoxin was produced only by A. sydowii and A. versicolor. This study proved the infection of aquacultures' fishes with mycotoxin-producing fungi. It recommends periodical examination of fishes grown in these aquacultures to ensure that they are devoid of fungal contamination to conserve the public health. © 2011 Academic Journals Inc.