Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Poultry Science (PhD)

Degree Level



Poultry Science


John A. Marcy

Committee Member

Casey M. Owens

Second Committee Member

Jason K. Apple


antimicrobials, bacteria reduction, broiler performance, livestock production, pathogen reduction, poultry production, Saccharomyces cerevisiae, Salmonella


The impacts of using health-promoting Saccharomyces cerevisiae fermentation metabolites in poultry production and processing can be measured in respect to multiple measures of success. Traditionally this yeast-based compound has been administered to poultry, livestock, poultry, and other species to improve animal performance and production volume output. In addition, Saccharomyces cerevisiae fermentation metabolites have also been shown in more recent research to reduce colonization of pathogenic bacteria in the host organism’s gastro-intestinal tract. In this dissertation, the impacts of administering a functional ingredient containing Saccharomyces cerevisiae metabolites on broiler performance measures and pathogen reduction were measured. One of the studies in this research was conducted in controlled environment research pens, in the absence of disease or stress. In this study, broiler feed conversions and component parts yields were similar between the control and treated broilers. As indicated by studies elsewhere, these results may have been different had the broilers been exposed to a commercial setting, or disease challenges, or other stressors. Also, ceca and parts that were provided by commercial plants that had processed broilers treated with a Saccharomyces cerevisiae metabolite product had lower presence and quantities of Salmonella in the ceca and component portions compared to samples obtained from non-treated broilers. In addition, the ceca provided by commercial plants which had been exposed to the Saccharomyces cerevisiae metabolite treatments had reduced Salmonella strength, with increased susceptibility to selected antimicrobials. There are several practical applications of this research. The metabolites of Saccharomyces cerevisiae fermentation may be considered in broiler and other meat-animal production systems as one alternative in the multi-hurdle approach to reduce pathogens. This technology may benefit some plants by reducing the need for in-plant interventions, such as antimicrobial sprays and dips frequently used to achieve regulatory standards. Researchers and integrators that choose to study the administration of the metabolites of Saccharomyces cerevisiae fermentation to meat animals can gain valuable knowledge by measuring the impacts on performance, yields, and pathogen presence in settings where the technology has been applied over an extended period of time in a variety of experimental conditions.