Functional Genomics to Increase Aflatoxin Resistance in Poultry
Modern domestic turkeys are the most susceptible animals known to the ubiquitous feed-borne mycotoxin aflatoxin B1 (AFB1), which causes diverse adverse effects including reduced productivity and feed efficiency, increased susceptibility to bacterial and viral diseases, and reduce vaccine effectiveness. In most animals, resistance is associated with expression of protective AFB1-detoxifying glutathione S-transferases (GSTs). Through NIFA Animal Genome program support, these researchers have determined that the extreme sensitivity of domestic turkeys is likely due to GST dysfunction caused by down regulation, gene silencing, and/or other mechanisms. In contrast, wild and heritage turkeys, which are relatively resistant, possess functional AFB1-detoxifying hepatic GSTs, implying that these enzymes were silenced as an unintended consequence of intensive breeding to produce the modern domestic turkey. The overall hypothesis behind this research is that identification of allelic variants underlying the AFB1-resistant phenotype can be used to develop diagnostic markers related to GST function to enhance innate resistance in poultry to the many diseases associated with this mycotoxin. The objectives of this project are to determine the AFB1-protective GST(s) in wild and heritage turkeys, to identify genetic markers associated with the AFB1-resistant phenotype, and to define the molecular mechanism responsible for GST dysfunction in domestic turkeys. The long-term goal is to leverage USDA’s investment in genomic research and the turkey genome sequencing project to enhance innate resistance by reintroducing AFB1 resistance into domestic poultry. This project will benefit industry through improvements in animal health, increased productivity, and provide a safer product for consumers.
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