Identification of Black Cattle that Resist Salmonella

The long-term goal of this research is to improve food safety and animal well being by promoting Salmonella-resistant beef cattle. Salmonella is increasingly prevalent in hamburger because this bacteria can infiltrate small tissues of the immune that are unavoidably ground into hamburger. The specific objective of this particular application is to develop a test that identifies black cattle bearing specific genes conferring the resistance. Preliminary data identified: (a) a single gene that confers Salmonella resistance to non-black cattle; and, (b) 34 genes whose diminished activity (expression) correlated with Salmonella resistance as evidenced by decreased infiltration of the pathogen into the immune tissues. These 34 genes all produce proteins that Salmonella has to use during the infection process.Our central hypothesis is that Salmonella resistance can be reliably predicted in black cattle via a genetic test targeting the 34 genes. The rationale underlying the proposed research is that these 34 genes encode proteins exploited by Salmonella during the infection process, and thus minimizing their expression will yield Salmonella resistance. Guided by strong preliminary data, we plan to objectively test our central hypothesis and attain the objective of this application by pursuing the following objectives: 1) To examine a larger group of cattle and confirm that the diminished expression of these 34 genes leads to Salmonella resistance in black beef cattle; and, 2) To identify the gene sequences that lead to the decreased expression in the 34 genes. Under the first objective, our preliminary data will be confirmed using samples from 500 additional animals. Under the second aim, we will sequence the genes encoding the 34 proteins in the top 10% (n=50) of cattle samples in which expression of the 34 genes was the lowest and was correlated with the lowest Salmonella prevalence (percent of cattle infected with Salmonella).The approach is innovative because it will be the first genetic test that identifies black beef cattle that naturally resist Salmonella infections. The proposed research is significant because it will establish a dependable assay for detecting these traits. Ultimately, such knowledge will diminish food borne Salmonella.