Occurrence of filamentous fungi and aflatoxins in poultry feedstuffs

Abstract

Sixty samples of poultry feedstuffs obtained from one manufactory and four farms located in Manaus, Amazonas State, Brazil, were studied for filamentous fungi and aflatoxin contamination. The following parameters were analyzed: fungal contamination, aflatoxigenic potential of Aspergillus flavus strains isolated, occurrence of aflatoxins and influence of abiotic factors (moisture content and water activity) on the mycoflora. The fungi were isolated on Sabouraud dextrose agar with chloramphenicol. Detection of aflatoxins was carried out by thin-layer chromatography (TLC). The genus Aspergillus was the most frequent (71.7%), followed by Rhizopus (28.3%), Absidia (26.7%), Penicillium (11.7%), Mucor (11.7%), Fusarium (10%), Cladosporium (1.7%), and Crysosporium (1.7%). Among the Aspergillus species, A. flavus was the most frequently isolated (53.3%). 44% of A. flavus strains were toxigenic and produced only Group B aflatoxins. The fungi were recovered from samples with moisture content and water activity ranging from 11.0% to 24.6% and from 0.91 to 0.61, respectively. The number of colony forming units of Aspergillus pergram (CFU/g) varied from 0.5 to 21.5 x 103. No aflatoxins were detected in the 60 samples analysed.