Graduate Studies
First Advisor
Byron D. Chaves
Second Advisor
Hiep Vu
Third Advisor
Bing Wang
Date of this Version
Summer 8-2024
Document Type
Thesis
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science
Major: Food Science and Technology
Under the supervision of Professor Byron D. Chaves
Lincoln, Nebraska, August 2024
Abstract
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) can cause morbidity and mortality in pigs of all ages with a high prevalence, causing an estimated product loss of $664 million annually in the United States in 2013. While vaccines exist, additional biosecurity measures are key to prevent and eliminate this virus from herds. This virus can be transmitted by biotic and abiotic vectors. In 2014, Porcine Epidemic Diarrhea Virus (PEDV) was hypothesized to be carried in feed ingredients. Understanding feed additives that can protect pigs from this affliction is helpful for controlling porcine viruses like PRRSV. This study was conducted to assess the efficacy of three clean-label antimicrobials containing polyphenols derived from lemon and grape against PRRSV. The antimicrobials tested were all from Prosur; Lemon Juice DH-10, PRS PHR W, and Natural Grape Flavor were added to minipig feed so that each additive was 0.5% of the total weight. PRRSV was added to the feed and tested over two weeks by virus infectivity assays conducted using cell culture. The real-time qRT-PCR test was conducted to confirm the presence of virus by detecting viral PRRSV RNA. Results of these assays showed that the least effective additive at reducing viral genomic RNA was Lemon Juice DH-10, however all samples maintained an average range of 27-32 Ct, with averages lower on Day 7 and highest on Day 1, 3 and 14. Infectivity of the virus after being exposed to the samples stayed close to 3.16 x 104.5 TCID50 /mL for the full 14 days, with less than half a log of reductions on Day 3 and Day 7. PRRSV remained detectable through Day 14 by real-time qRT-PCR and by viral infectivity assay when stored at room temperature. This study can function as a primer for a larger study to investigate polyphenol-containing additives effects on porcine virus survivability. This is a risk that should be considered when pork producers consider preventative measures against porcine viruses.
Advisor: Byron D. Chaves
Comments
Copyright 2024, Vanessa Whitmore. Used by permission