Coated fatty acids alter virulence properties of Salmonella Typhimurium and decrease intestinal colonization of pigs.

Area of Science:

• Veterinary Microbiology
• Food Safety
• Animal Nutrition

Background:

• * Salmonella Typhimurium infections in pigs are a significant source of human foodborne illness.
• * Acidification of feed and water is a common strategy to control pig infections.
• * Short-chain fatty acids (SCFAs) and medium-chain fatty acids (MCFAs) are potential feed additives.

Purpose of the Study:

• * To evaluate the impact of SCFAs and MCFAs on Salmonella Typhimurium virulence gene expression.
• * To assess the efficacy of these fatty acids in reducing Salmonella colonization and shedding in pigs.
• * To compare the effects of coated versus uncoated fatty acids.

Main Methods:

• * Determination of minimal inhibitory concentrations (MICs) for 4 SCFAs and 2 MCFAs against 54 porcine Salmonella Typhimurium strains.
• * In vitro analysis of virulence gene expression (fimA, hilA) and bacterial invasion using sub-MIC concentrations of fatty acids.
• * In vivo study involving pigs experimentally infected with Salmonella Typhimurium, supplemented with coated or uncoated butyric acid.

Main Results:

• * MCFAs exhibited lower MIC values than SCFAs.
• * Sub-inhibitory concentrations of caproic/caprylic acid reduced fimA expression; butyric/propionic/caproic/caprylic acid reduced hilA expression and invasion.
• * Coated butyric acid significantly decreased fecal shedding and intestinal colonization in pigs, but not tonsil, spleen, or liver colonization.

Conclusions:

• * Coated butyric acid demonstrates potential for reducing Salmonella Typhimurium load in pigs.
• * Dietary supplementation with specific coated fatty acids may be a viable strategy to mitigate Salmonella in swine.
• * Further research into coated fatty acids could enhance food safety and reduce zoonotic disease transmission.