Tissue-, age- and dose-dependent changes in avian β-defensin and LEAP2 mRNA abundance in the intestines of Salmonella Typhimurium challenged broilers

Abstract

Salmonella is a pathogen normally found in the gastrointestinal tract of poultry. The objective of this study was to determine changes in avian β-defensin (AvBD) and liver-enriched antimicrobial peptide 2 (LEAP2) mRNA following Salmonella challenge. Day of hatch chicks were challenged with 10⁶, 10⁷ or 10⁸ 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 10⁸ 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.

Keywords:

• Salmonella typhimurium
• Avian β-defensin
• LEAP2

Acknowledgments

We would like to thank Denise Caldwell and Wade Hanson at USDA-ARS for their help with this project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Funding for this work was provided in part by the Virginia Agricultural Council, the Virginia Agricultural Experiment Station and the Hatch Program of the National Institute of Food and Agriculture, U.S. Department of Agriculture. JG was supported in part by a fellowship from the College of Agriculture and Life Sciences George Washington Carver and Graduate Teaching Scholar programs at Virginia Tech.