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Title: Effect of pre-slaughter stressors on intestinal microbial populations of pigs

item Rostagno, Marcos
item RICHERT, BRIAN - Purdue University
item Lay Jr, Donald

Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2012
Publication Date: 7/15/2012
Citation: Rostagno, M.H., Richert, B.T., Lay Jr, D.C. 2012. Effect of pre-slaughter stressors on intestinal microbial populations of pigs. Joint Abstracts of the American Dairy Science and Society of Animal Science. Proceedings.

Interpretive Summary:

Technical Abstract: The swine intestinal microbiota is a complex ecosystem, which may be disturbed by many factors. Studies have focused on the relation between antimicrobial use and resistance in intestinal microbial populations, whereas the effect of non-antimicrobial factors, such as stress, remains unknown. During the process of being transported from production farms to abattoirs, market pigs are exposed to a variety of stressors. The occurrence of antimicrobial resistance in market pigs is critical, since the most likely route of transmission from animals to humans is through contamination of carcasses. Therefore, two experiments were conducted to determine the effect of common pre-slaughter stressors (feed withdrawal, transportation, and lairage) on the levels of antimicrobial resistance in commensal coliforms and lactobacilli in market pigs. In the first study, no effect of transportation and lairage on total fecal coliforms or its subpopulations resistant to antibiotics was observed. Also, no effect was observed on total fecal lactobacilli populations, as well as on subpopulations resistant to tetracycline and erythromycin. However, a significant increase of the fecal levels of ampicillin-resistant lactobacilli was caused by transportation and lairage (P<0.05). In the second study, while total ileal coliforms were not affected by feed withdrawal and/or transportation, ileal populations of lactobacilli resistant to tetracycline and erythromycin decreased (P<0.05) in response to the stress of feed withdrawal and transportation. Interestingly, no effect of the investigated stressors was observed in any of the cecal microbial populations analyzed. These studies show that stress does affect intestinal microbial populations in market pigs with lactobacilli being more susceptible to the effects of stressors compared to coliforms. Moreover, it was revealed that interactions between type of stressors, region of the intestinal tract, and microbial population analyzed may influence the pattern of antimicrobial resistance observed. There is a critical need for further investigation of the quantitative effect of stressors on intestinal microbial populations of pigs, and its food safety implications.