Identification of toxigenic Aspergillus species from diet dairy goat using a polyphasic approach

Abstract

Some species of filamentous fungi that infest agricultural commodities are able to produce mycotoxins, contaminating feed and animal products. The aim of this research was to identify the mycoflora present in the feed and forage for dairy goat and to isolate and characterize the Aspergillus flavus and A. parasiticus strains based on a morphological and molecular characterization and mycotoxigenic ability. The goat dairy diets were collected monthly from 11 goat milk farms, totaling 129 and 106 samples of concentrate and forage, respectively. For the isolation of the mycobiota the surface plating method was used. Aspergillus, Penicillium, and Fusarium were the main fungi producing mycotoxins isolated. The morphological and molecular characterization and mycotoxigenic ability were used for A. flavus and A. parasiticus identification. The Aspergillus spp. from feed 39% produced aflatoxins B1 and B2, 17% produced cyclopiazonic acid (CPA), 18% produced both toxins, and 42% had no toxigenic ability. Only 2.0% of the strains produced aflatoxins B1, B2, G1, and G2, but no CPA. The strains from forage were producers of aflatoxins B1 and B2 (37%), CPA (14%), 14% of both mycotoxins, whereas 49% have shown no toxigenic ability. The aflD and aflR genes were used by PCR and PCR-RFLP, respectively. The presence of toxigenic species in samples of feed for lactating goats indicates a potential risk of contamination of dairy products, if they are exposed to environmental conditions favorable to fungal growth and mycotoxin production.