| dc.description.abstract | The research evaluated in this thesis focuses on Salmonella infection in turkeys. In both experiments, poults were randomly placed into pens of four experimental treatment groups. These four treatments groups consisted of a traditional feeding program inclusive of an AGP (positive control, PC), a basal diet (absent of AGP) (negative control, NC), and two additional basal diets consisting of two different brands of commercially available DFMs (both Bacillus Subtilis strains) (DFM1 and DFM2, respectively).
The initial experiment focused on examining an alternative inoculation methodology in order to better represent Salmonella transmission and introduction into a commercially produced flock. Simultaneously, effects and possible relationship of inoculation period and administration of feed treatments were evaluated. Experiment 1 focused solely on the first six weeks, which is a typical brooding period for commercial turkeys. Experiment 2 focused more heavily on the various feed treatments and their effects on turkey hen performance and impact on Salmonella colonization. This second experiment focused on the entire lifespan typical of commercially reared turkey hens, which is approximately 12 weeks.
Data collected included weekly body weights, environmental overshoe gauze booties taken from day of placement through trial terminations, liver and ceca plate counts from 7 through 42 days, jejunum measurements at 12 weeks, feed conversion and mortality. Over the course of both experiments, data collected from litter booties, ceca colonization, and liver invasion demonstrated evidence of the alternative inoculation model effectiveness. In Experiment 1, significant differences were only observed across treatments in mean body weights and livability. The negative control exhibited significantly lower adjusted livability at 0 to 42 days. In Experiment 2, jejunum morphology samples further indicated successful Salmonella colonization and comparable treatment efficacies by increased mucosal barrier protection in PC, DFM1 and DFM2. Mean body weights at 12 weeks in Experiment 2 also indicate a similar relationship with no significant difference in PC and DFM2. These data indicate that the alternative inoculation methodology could be utilized as a means to mimic a field challenge and DFMs can be effective as a potential alternative to AGP in commercial turkey operations. | en |
