Date of Graduation

5-2012

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor

Daniel J. Donoghue

Committee Member

Annie M. Donoghue

Second Committee Member

Michael F. Slavik

Abstract

Campylobacter spp. has been identified as one of the leading causative agents of food borne diarrheal illness. Epidemiological evidence has shown that poultry is the main source for human infection. Poultry are asymptomatic carriers of Campylobacter within their gastrointestinal tract, with colonization levels reaching 106-108 cfu/g cecal content. Surveys of domestic poultry flocks have estimated that approximately 90% of flocks are positive for Campylobacter colonization. Risk assessment studies have determined that by reducing levels of Campylobacter colonization during rearing, incidences of human infection will be significantly reduced. Currently there are no consistently effective treatments to eliminate Campylobacter from poultry flocks. The use of natural plant extracts to control food borne pathogens is an area of resurgent interest due to growing consumer demand for removal of sub-theraputic administration of antibiotics in conventionally raised livestock and the increased demand for organic meat products. Extracts from American Cranberry (Vaccinium macrocarpon) contain proanthocyanidins which have demonstrated antimicrobial activity against other food borne pathogens including E. coli, Salmonella, and Listeria. However, their ability to reduce Campylobacter in chickens has not been reported. The objective of this study was to evaluate two different cranberry extracts, either containing a lower (1%) or higher concentration (30%) of proanthocyanidins by the manufacturer (L-PAC or H-PAC, respectively), to inhibit the growth of Campylobacter, in vitro and in vivo. In replicate in vitro trials, a 0.1 or 0.5% dose had no effect, the 1% dose produced a modest reduction and the 2 or 4% doses produced at least a 5 log reduction in Campylobacter counts when compared to controls 8 or 24 hours after inoculation. For the in vivo studies, 70 chicks were randomly assigned to one of seven treatment groups (n=10 per treatment group). Treatment groups for each trial included a positive Campylobacter

control (no cranberry extract) or 0.5%, 1%, or 2% of either H-PAC or L-PAC added to the feed. The same dosages were used in two replicate trials. For each trial, all birds were given feed supplemented with H-PAC or L-PAC, except for positive Campylobacter controls, starting at day of placement and continuing through the entire 14 day trial. At day 7 all birds were challenged with a mixture of three wild type Campylobacter jejuni strains by oral gavage (approximately 2.5 x105 cfu/mL). On day 14, birds were euthanized by CO2 and cecal contents were collected for enumeration of Campylobacter. In both trials cecal Campylobacter counts were not reduced by administration of L-PAC or H-PAC in the feed. Follow up experiments are needed to increase the potency of these cranberry extracts to reduce this important food borne pathogen in chickens.

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