Investigating the Impact of Stress on Foodborne Pathogen Colonization in Turkeys

We hypothesize that the response to common stressors of commercial turkey production,
including Escherichia coli respiratory disease (airsacculitis), moving and transport,
and temperature extremes, can increase pre-harvest contamination of turkeys with
pathogens of food safety importance, and that basic understanding of how turkey
immunity is affected by stress will lead to the development and application of
practical strategies to improve product safety. Because stress has been shown to both
increase disease resistance at low levels and decrease disease resistance at high or
sustained levels, its effects on food safety have been difficult to quantify. We
have developed transport stress and cold stress models which result in repeatable
levels of stress-induced infection of turkeys with E. coli. We will use these models
to study the colonization of turkeys with other bacteria of food safety importance.
Cell culture studies of the interaction between bacterial pathogens and primary
turkey synovial cells, macrophages, and heterophils, from normal and stressed animals
will provide basic data and systems for testing the efficacy of therapeutic and
prophylactic products to modulate the stress response, improve disease resistance,
and decrease carcass contamination with pathogens. Novel non-antibiotic
interventions will include antimicrobial peptides and acute phase proteins that will
be developed using exploratory analysis of physiological reactions in our stress
models as described in the previous section. These products will be incorporated
into stress models; however variations in both dosage and timing relative to stressor
will be emphasized in multiple experiments to maximize production gains while
minimizing pathogen contamination. <BR><BR>