Date of Graduation

5-2016

Document Type

Thesis

Degree Name

Master of Science in Food Science (MS)

Degree Level

Graduate

Department

Food Science

Advisor

Steven C. Ricke

Committee Member

Jeff Lewis

Second Committee Member

Steven Foley

Abstract

Salmonella is a foodborne pathogen commonly associated with poultry products; the economic burden to the U.S. is estimated to be approximately $693 million (without factoring in contaminated eggs). Recently, there has been pressure to withdraw sub-therapeutic levels of antibiotics (also known as antibiotic growth promoters; AGP) from poultry due to concern over antibiotic-resistant bacteria spreading to the human population. Therefore, various feed additives have been researched for their ability in providing protection against harmful pathogens and their potential growth promoting effects, both of which were attributes of poultry treated with AGP. This thesis consists of a comprehensive literature review that covers prebiotics and similar compounds, along with their effects on the microbiome. Additionally, the research described in this thesis utilized an in vitro anaerobic mixed culture assay as well as an in vivo feeding trial to determine the effects of Original-XPCTM (XPC; a compound similar to a prebiotic) on Salmonella survival and cecal microbiota modulation. The in vitro study resulted in rapid and significant reduction (from approximately 1.0 to 2.0 logs) of the survival of Salmonella in the XPC treatment by the 24 h plating timepoint at both the 28 and 42 d sampling ages. However, by the 48 h plating timepoint at the 42 d sampling age, all the treatments containing cecal contents were able to reduce the Salmonella recovered to the same degree. These findings suggest the ability of XPC to accelerate the rate at which the cecal microbiota is able to reduce Salmonella invasion. Analysis of the cecal microbiota in both the in vivo and in vitro assays revealed no significant differences in species diversity and richness among treatments. However, cecal microbiota maturity revealed significantly increased species diversity and richness, indicating bird age to be critical in the modulation of the cecal microbiota.

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