Title: Colonization of day-of-hatch broiler chicks with antimicrobial resistant strains of salmonella Heidelberg and Kentucky Authors
Submitted to: Poultry Science Association
Publication Type: Abstract Only
Publication Acceptance Date: April 16, 2012
Publication Date: July 9, 2012
Citation: Cosby, D.E., Cray, P.J., Harrison, M.A., Cox Jr, N.A., Buhr, R.J., Wilson, J.L. 2012. Colonization of day-of-hatch broiler chicks with antimicrobial resistant strains of salmonella Heidelberg and Kentucky. Poultry Science Association. 91(Suppl.1):56. Technical Abstract: Salmonella is a major foodborne pathogen linked to poultry and poultry products. However, limited research regarding the in vivo interactions of non-host adapted Salmonella serotypes in broiler chicks is available. In order to evaluate the effect of two serotypes on colonization, 600 day-of-hatch chicks were obtained from a local commercial hatchery and divided between four treatment rooms (n=150/room). Forty-five seeder chicks were orally inoculated with 1.8 x 104 cfu of Salmonella Kentucky resistant to tetracycline (SKTetR) while an additional 45 seeder chicks were inoculated with 2.2 x 104 cfu of Salmonella Heidelberg resistant to streptomycin (SHStrR). Fifteen wing-banded seeder chicks of each serotype were placed into three replicate treatment rooms; one additional room was maintained as a negative control with the same bird density and the 30 additional chicks gavaged with sterile saline. On days 7 and 28 post commingling, the ceca of 15 non-seeder chicks per room were aseptically removed and cultured, and on day 42, the ceca of 30 non-seeder chicks were removed and cultured for the presence of Salmonella. Ceca from all control room chicks sampled were negative for Salmonella while on day 42 - 83, 96, and 82% of the ceca sampled from the treatment rooms containing seeder chicks were positive for SKTetR, SHStrR, or both serotypes of Salmonella, respectively. After processing on day 43, a statistically significant difference in the recovery of SKTetR and SHStrR was detected from post chill carcass rinsates (P<0.05). Carcass Salmonella recovery was lowered to 18% for SKTetR vs. 35% for SHStrR, and 4.2% for both serotypes following immersion chilling. Since there were no overall differences detected from the cecal samples during grow-out and the fact that all ceca were positive for both serotypes on day 28 d, no exclusion between these serotypes was observed in this study during grow-out. However, Salmonella serotype prevalence in ceca samples collected prior to the day of processing (pre-feed withdrawal) may not be predictive of the recovered Salmonella serotypes from post-chill carcasses.