Aflatoxin B1 Contamination and Fungal Diversity in Oilseed Cakes and Formulated Feeds from Feed Markets in Addis Ababa and Surrounding Areas

Abstract This study was conducted in Addis Ababa, surrounding peri-urban and urban feed markets to assess the prevalence of aflatoxin B1and identify fungal diversity in feeds. Two hundred and ninety samples of oil seed cakes and formulated feeds were collected. The results indicated that, 92% of poultry ration, 72% of dairy ration, 66% of linseed cake, 64% of noug seed cake, 61% of cotton seed cake, and 36% of soybean cake were contaminated with aflatoxin B1 exceeding the permissible level (20 μg/kg). To evaluate fungal diversity, genomic DNA was extracted, pooled by feed type, and sequenced. The findings revealed variations in the diversity indices of fungal phyla, families, genera and species. The Metabarcoding results revealed Ascomycota as the dominant phylum in all feeds, with Aspergillaceae, Nectriaceae, Botyosphaeriaceae, and Cladosporiaceae being the dominant families accounting for 53%, 43%, 16%, 33%, 11%, and 28% of the total fungal families detected in cotton seed cake (S1), noug seed cake (S2), soybean cake (S3), linseed cake (S4), poultry ration (S5), and dairy ration (S6), respectively. The synergistic presence of multiple fungal species, some of which are known to be harmful, was identified in the feed samples. Among the species, the proportion of Aspergillus flavus found was 1.8%, 3.8%, 0%, 0.4%, 1.2%, and 1.2% in the feeds S1–S6, respectively. The findings highlight the critical need for enhanced feed management practices, improved education and training for feed handlers, and stricter regulatory measures to mitigate aflatoxin contamination.