Morphometric and Genomic Characterization of Toxigenic Aspergillus Isolates Associated with Poultry Feeds and Feed Ingredients from Five Agro-Ecological Zones of Nigeria

Abstract

Introduction: Toxigenic aspergilli are storage contaminants of poultry feeds and feed ingredients which produce secondary metabolites known as mycotoxins in these products. This research is aimed at detecting and characterizing mycotoxin producing aspergillus species present in feeds given to poultry birds and in the ingredients used in the production of these feeds. Method: A total of 102 samples of feed (n=30) and feed ingredients (n=72) were collected across 5 agro-ecological zones of Nigeria and analyzed for toxigenic Aspergilli using morphometric and molecular genomic characterization techniques. Different mycological media was used for isolation, by deploying pour plate method. The Aspergilli isolates morphometric identity were characterized using macroscopic and microscopic observed features. The isolated Aspergillus species were further characterized molecularly using genomic characterization protocols. Results: The results of the morphometric characterization indicated that nine (9) Aspergillus species were detected in the feed and feed ingredients, with Aspergillus flavus having the highest rate of occurrence among the isolates. Furthermore, the genomic typing using internal transcribe spacer (ITS) as a barcode, as well as comparison of the fungal isolates with other Aspergillus species in the genebank showed 99-100% similarity. Also, toxigenic gene typing indicated that some of the A. flavus were toxigenic with the detection of the following genes Nor-1, ver-1, OmtB and AflR. Conclusion: The findings of this study showed that toxigenic Aspergilli isolates are present in both poultry feed and feed ingredients from 5 agro-ecological zones in Nigeria and poses great public health issues.