| In these studies, we evaluated candidate Salmonella vectored Salmonella vaccines, a method to screen for Bacillus probiotics, and evaluated novel Bacillus probiotic candidates in commercial turkeys. After Salmonella vaccine candidates were administered to neonatal chicks, clearance of the vaccine strains as well as protection conferred against a heterologous challenge strain were measured. While no protection against the heterologous challenge was noted, an increased clearance rate as compared to wild type Salmonella or the attenuated Salmonella empty vector strain was observed. In a second study, a method for screening and evaluating potential Bacillus probiotic candidates was developed. This method allows for the selection of nonpathogenic, heat tolerant, efficiently sporulating Bacillus isolates which are also capable of killing both Salmonella Enteritidis and Clostridium perfringens in vitro . In a final study, Bacillus isolates identified using the methods developed in the second study, were evaluated under commercial turkey brooding conditions. One isolate, PHL-NP122, caused a significant (p &le 0.05) increase in body weight and body weight gain. This same isolate also significantly (p &le 0.05) decreased the percentage of turkey poults positive for Salmonella in their ceca and significantly reduced (p &le 0.05) the number of Salmonella recovered from the ceca. This data may indicate that this isolate may be a potential alternative to organic arsenicals used for growth promotion in commercial turkeys. |
