Infection dynamics of Salmonella Infantis vary considerably between chicken lines

Area of Science:

• Veterinary Microbiology
• Immunology
• Poultry Science

Background:

• Salmonella Infantis is a prevalent serovar in European broiler production.
• Fast-growing broiler chickens are reportedly more susceptible to Salmonella infections than slow-growing or layer breeds.

Purpose of the Study:

• To investigate the infection dynamics and immunological responses of different chicken lines to Salmonella Infantis.
• To compare the susceptibility and shedding patterns of commercial and experimental chicken lines.

Main Methods:

• Four chicken lines (Ross 308, Hubbard ISA-JA-757, SPF layers, SPF broilers) were infected with Salmonella Infantis at 2 days of age.
• Evaluated faecal shedding, bacterial colonization in ceca, and systemic spread to liver and spleen.
• Assessed humoral and cellular immune responses, including antibody production and immune cell subsets.

Main Results:

• Fast-growing broilers (Ross 308) exhibited the highest faecal shedding and systemic bacterial spread.
• SPF layers demonstrated significantly lower shedding and cecal colonization compared to broilers.
• All infected chicken lines showed transmission to in-contact birds and developed antibody responses by 21 days post-infection.

Conclusions:

• Chicken line significantly influences Salmonella Infantis infection dynamics and susceptibility.
• Fast-growing broilers pose a higher risk for Salmonella Infantis transmission due to increased shedding and colonization.
• Findings highlight the importance of chicken genetics in Salmonella control strategies for poultry and human health.