Molecular Characterization of Aspergillus flavusStrains Isolated from Animal Feeds

Aflatoxin (AF)-producing fungi such as Aspergillus flavuscommonly contaminate animal feeds, causing high economic losses. A. flavusis the most prevalent and produces AFB1, a potent mutagen, and carcinogen threatening human and animal health. Aspergillaceaeis a large group of closely related fungi sharing number of morphological and genetic similarities that complicate the diagnosis of highly pathogenic strains. We used here morphological and molecular assays to characterize fungal isolates from animal feeds in Southwestern Algeria. These tools helped to identify 20 out of 30 Aspergillusstrains, and 15 of them belonged to the Aspergillussection Flavi. Further analyses detected four out of 15 as belonging to Aspergillus flavus-parasiticusgroup. PCR targeting the AF genes’ aflR-aflS(J)intergenic region amplified a single 674 bp amplicon in all four isolates. The amplicons were digested with a BglII endonuclease, and three specific fragments were observed for A. flavusbut A. parasitucuslacked two typical fragments. Sequencing data of four amplicons confirmed the presence of the two BglII restriction sites yielding the three fragments, confirming that all four strains were A. flavus. In addition, this analysis illustrated the genetic variability within the A. flavusstrains.