Investigation of the potential of aerosolized salmonella enteritidis on internal organ colonization in broilers between age of D 3 to D 21

Authors: PAL, AMRIT - Auburn University; RIGGS, MONTANA - Auburn University; URRUTIA, ANDREA - Auburn University; OSBORNE, RACHEL - Auburn University; JACKSON, ALLY - Auburn University; BAILEY, MATTHEW - Auburn University; MACKLIN, KEN - Auburn University; PRICE, STUART - Auburn University; Buhr, Richard - Jeff; BOURASSA, DIANNA - Auburn University

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2021
Publication Date: 12/1/2021
Citation: Pal, A., Riggs, M.R., Urrutia, A., Osborne, R., Jackson, A., Bailey, M.A., Macklin, K.S., Price, S.B., Buhr, R.J., Bourassa, D.V. 2021. Investigation of the potential of aerosolized salmonella enteritidis on internal organ colonization in broilers between age of D 3 to D 21. Poultry Science. https://doi.org/10.1016/j.psj.2021.101504.
DOI: https://doi.org/10.1016/j.psj.2021.101504

Interpretive Summary: The presence of Salmonella in the air of poultry houses has been previously confirmed. Therefore, it is important to investigate the potential for entry of Salmonella into broilers through the air. The present study aimed to evaluate the potential of different levels of Salmonella aerosol inoculations for broiler chicks and the colonization in their ceca, liver/spleen, and trachea over time. For each of the three independent trials, a total of 112 day old birds were randomly divided into four groups (n=28/group). On d 1 of bird age, one group was exposed to an aerosol of sterile saline (control) and the remaining three groups were exposed to an aerosol generated from one of three doses (1,000 CFU/mL, 100,000 CFU/mL, and 100,000,000 CFU/mL) of S. Enteritidis inoculum. Aerosol exposure time was 30 min/group and was performed using a nebulizer. On days 3, 7, 14, and 21 of age, ceca, liver/spleen, and trachea were aseptically removed. Ceca were cultured for Salmonella counts (CFU/g) and all other tissues were cultured for Salmonella prevalence. All sampled tissues from the control group were Salmonella negative. On sampling days 3 and 7, ceca Salmonella counts were highest (5.14 and 5.11, respectively) when challenged with the highest level of Salmonella. Ceca Salmonella counts increased from day 3 (2.43) to 7 (4.43) and then remained constant following inoculation with the lowest level of Salmonella, and counts decreased over time for all other groups. For each tissue type, Salmonella prevalence increased with increasing inoculum levels at all sampling timepoints. Salmonella prevalence was low (0 to 22%) and did not change over time following lowest Salmonella inoculation. Prevalence decreased over time in ceca and trachea following intermediate and highest Salmonella inoculation. Liver/spleen Salmonella prevalence increased from day 3 (72%) to day 14 (100%) and then decreased at day 21 (56%) in birds exposed to an aerosol of highest inoculum of Salmonella. Overall, this study demonstrated the Salmonella colonization and persistence in different tissues of broilers following exposure to Salmonella aerosol.

Technical Abstract: The presence of Salmonella in air of poultry houses has been previously confirmed. Therefore, it is important to investigate the entry of Salmonella in broilers through air. The present study aimed to evaluate the potential of different levels of Salmonella Enteritidis aerosol inoculations in broiler chicks for colonization in their ceca, liver/spleen, and trachea over time. For each of the three independent trials, a total of 112 1-d old birds were randomly divided into four groups (n=28/group). On d 1 of bird age, one group was exposed to an aerosol of sterile saline and the remaining three groups were exposed to an aerosol generated from one of three doses (10^3 CFU/mL, 106 CFU/mL, and 10^9 CFU/mL) of S. Enteritidis inoculum. Aerosol exposure time was 30 min/group and was performed using a nebulizer. On d 3, 7, 14, and 21 of age, ceca, liver/spleen, and trachea were aseptically removed. Ceca were cultured for Salmonella counts (log10 CFU/g) and all tissues were cultured for Salmonella prevalence. All sampled tissues from the control group were Salmonella negative. On sampling d 3 and 7, ceca Salmonella counts were highest (5.14 and 5.11, respectively) when challenged with 10^9 CFU/mL S. Enteritidis (P = 0.0281). Ceca Salmonella counts increased from d 3 (2.43) to d 7 (4.43) and then remained constant following inoculation at 10^3 CFU/mL S. Enteritidis, and counts decreased over time for all other groups. For each tissue type, Salmonella prevalence increased with increasing inoculum levels at all sampling timepoints (P = 0.0213). Salmonella prevalence was low (0/18 to 4/18) and did not change over time following 103 CFU/mL S. Enteritidis inoculation (P = 0.2394). Prevalence decreased over time in ceca and trachea following 10^6 and 10^9 CFU/mL Salmonella inoculation (P = 0.0483). Liver/spleen Salmonella prevalence increased from d 3 (13/18) to d 14 (18/18) and then decreased at d 21 (10/18) in birds exposed to an aerosol of highest inoculum of S. Enteritidis. Overall, this study demonstrated the Salmonella colonization and persistence in different tissues of broilers following exposure to Salmonella aerosol.