Browsing by Author "Garcia, Javier S."
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- Expression of nutrient transporters and host defense peptides in Campylobacter challenged broilersGarcia, Javier S.; Byrd, J. Allen; Wong, Eric A. (2018-10)Campylobacter is a bacterium that colonizes the lower gastrointestinal tract of poultry and may influence the intestinal environment to promote its survival. The objective of this study was to characterize the effects of Campylobacter challenge on the mRNA abundance of nutrient transporters and host defense peptides (HDP), such as the avian beta-defensins (AvBD) and liver expressed antimicrobial peptide 2 (LEAP2). On the day of hatch, broiler chicks were challenged with one of three (10(6), 10(7), 10(8) colony-forming units, cfu) levels of Campylobacter jejuni. Quantitative PCR analysis revealed that there were dose-, tissue-, and agespecific changes in gene expression for both nutrient transporters and HDP. Expression of zinc transporter 1 (ZnT1) mRNA increased on d 7 in the duodenum, ileum, and cecum of birds challenged with 10(6) cfu of C. jejuni. At d 14, there was upregulation of the amino acid transporter b(o,+)AT mRNA in the duodenum, jejunum, and ileum of birds challenged with 10(6) cfu of C. jejuni. Other transporters such as EAAT3, GLUT2, SGLT1, and ZnT1 showed upregulation of mRNA in the ileum of the 10(6) cfu challenged group. There was a delayed response of the HDP to the C. jejuni challenge, with only a few HDP changed at d 7 but all HDP changed at d 14. At d 7, there was upregulation of AvBD10 mRNA in the duodenum of the 10(6) cfu challenged group but downregulation of AvBD10 in the ileum and AvBD12 and LEAP2 in the cecum of the 10(8) cfu challenged group. At d 14, there was upregulation of AvBD1, AvBD6, AvBD8, AvBD10, AvBD11, AvBD12, and AvBD13 mRNA in the ileum and cecum of the 10(6 )cfu challenged group but not the 10(7) and 10(8) cfu challenged groups compared to control. These results indicated that at a low dose (10(6) cfu) of C. jejuni, intestinal cells increased nutrient transporter and AvBD mRNA abundance to try to counter the infection, but that at higher doses the cellular response was suppressed.
- Temporal and Tissue Specific Changes in Expression of Nutrient Transporters and Host Defense Peptides in Young Broilers during Salmonella and Campylobacter infectionsGarcia, Javier S. (Virginia Tech, 2017-06-13)Salmonella and Campylobacter are the leading causes of bacterial foodborne illness in the United States. Commonly found in the gastrointestinal tract of poultry, Salmonella and Campylobacter may show little to no signs of infection in birds. The objective of this dissertation was to evaluate the influence on mRNA abundance of nutrient transporters and host defense peptides (HDPs) during a Salmonella or a Campylobacter challenge in young commercial broilers. Comparisons were made between non-challenged and challenged (106, 107, or 108 colony forming units of Salmonella or Campylobacter) broilers on expression of nutrient transporters and host defense peptides in the duodenum, jejunum, ileum and cecum at various days after inoculation. During a Salmonella challenge, changes in mRNA abundance of nutrient transporters and avian beta-defensins (AvBD) vary by day, tissue and challenge dose. ZnT1 may play an important role during a Salmonella challenge as mRNA abundance of ZnT1 significantly increased (P<0.05) by day 7 in the 108 group compared to the control. Early changes in LEAP2 mRNA abundance were observed in the 106 group than the 107 and 108 groups. However, at a later time point post challenge, a lower abundance of almost all AvBD mRNA (P<0.05) was observed in the lower gastrointestinal tract especially in the 107 and 108 groups compared to the control group, indicating that the pathogen may be influencing intestinal expression of AvBD mRNA. In Campylobacter, analyses revealed that expression of zinc transporter 1 (ZnT1) increased (P<0.05) in the duodenum, ileum and ceca in the 106 group on day 7. An increase (P<0.05) in the expression of avian beta-defensins were observed on day 14 in the ileum and ceca in the 106 group compared to the control group. Pathogens like Salmonella and Campylobacter may have an influence on the mRNA abundance of nutrient transporters and HDPs. Manipulation of these genes may ensure the survivability of these pathogens. Through sequestration of nutrients, the pathogen would have the ability to colonize the host and replicate. However, it must evade the host immune system as well. The processing of infected poultry with these pathogens may lead to foodborne illness in humans. Further research is needed to investigate possible methods to counter the influence these pathogens have on host immunity genes.
- Tissue-, age- and dose-dependent changes in avian beta-defensin and LEAP2 mRNA abundance in the intestines of Salmonella Typhimurium challenged broilersGarcia, Javier S.; Byrd, J. Allen; Wong, Eric A. (2020-03-18)Salmonella is a pathogen normally found in the gastrointestinal tract of poultry. The objective of this study was to determine changes in avian beta-defensin (AvBD) and liver-enriched antimicrobial peptide 2 (LEAP2) mRNA following Salmonella challenge. Day of hatch chicks were challenged with 10(6), 10(7) or 10(8) colony-forming units (cfu) of Salmonella typhimurium. There were dose-, tissue- and age-specific changes in AvBD and LEAP2 mRNA. At 1-day post-infection (dpi) there was a transient upregulation of AvBD1, 8, 10 and 12 mRNA in the 10(8) cfu group. At 5 dpi, all seven AvBD mRNA were downregulated in the ileum, while only AvBD1, 6, 10 and 11 mRNA were downregulated in the jejunum and AvBD6, 8, 10, 12 and 13 were downregulated in the cecum. At 7 dpi, there was downregulation of all seven AvBD mRNA in the duodenum and downregulation of selected AvBD in the jejunum, ileum and cecum. LEAP2 mRNA was downregulated at all doses of Salmonella in the cecum at 1 dpi and in the ileum at 5 dpi. In summary, Salmonella infection caused an initial upregulation followed by a downregulation of AvBD mRNA.
- Use of Foaming Disinfectants and Cleaners to Reduce Aerobic Bacteria and Salmonella on Poultry Transport CoopsHinojosa, Carolee; Caldwell, David; Byrd, James; Droleskey, Robert; Lee, Jason; Stayer, Phil; Resendiz, Erin; Garcia, Javier S.; Klein, Stephanie; Caldwell, Denise; Pineda, Megan; Farnell, Morgan (MDPI, 2018-11-02)Transport coops are infrequently washed and have been demonstrated to cross-contaminate broiler carcasses. We hypothesized that peracetic acid or a chlorinated cleaner, commonly used within poultry processing plants, can also be used to disinfect transport coops when applied via a compressed air foam system (CAFS). A mixture of fresh layer manure and concentrated Salmonella Typhimurium (ST) was evenly applied to the floors of four pre-cleaned transport coops and allowed to dry for thirty minutes. Treatments consisted of a (1) water rinse only, (2) product application with a water rinse, (3) product application followed by power washing and (4) power washing followed by application of product. Each foaming treatment was applied with a compressed air foam system and allowed 10 min of contact time. Samples were aseptically collected from the transport coops prior to and following treatment using a sterile 2 × 2-inch stainless steel template and a gauze swab pre-enriched with buffered peptone water. The chlorinated cleaner significantly (p < 0.05) reduced aerobic bacteria and ST by 3.18 to 4.84 logs across application methods. The peroxyacetic acid (PAA) disinfectant significantly (p < 0.05) reduced aerobic bacteria and ST by 3.99 to 5.17 logs across application methods. These data indicate that a compressed air foam system may be used in combination with a commercially available cleaner or disinfectant to reduce aerobic bacteria and ST on the surfaces of commercial poultry transport coops.