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Effects of a Variety of Stress Factors on the Immune Systems of Poultry and Subsequent Infection of Shell Eggs by Salmonella enteritidis


The role of the hen immune system in influencing the contamination of eggs by Salmonella Enteritidis will be studied. The goal will be to discover stress factors that can weaken the immune system and increase the chances of contamination of eggs. Potential strategies to control these stresses or to enhance immune resistance will result.

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Salmonella enteritidis (S. E.) carried by chickens and transmitted via shell eggs has become a major source of human intestinal infections. Despite the tremendous efforts made by the poultry industry, no effective measurements for elimination of S. E. colonization have been generated. Since the rate of horizontal transmission among chickens and egg-laying hens is very rapid, general hygiene measurements are not as effective as desired.</p>
The purpose of this study is to examine variables affecting the immune response of hens against S. E., especially under stress conditions. </p>
Hens with a weak immune system are likely to be more susceptible to S.E. infections. Activating the hens= immune system, such as by immunization,can prevent or eliminate the infection. </p>
This study will help us identify the factors that can up-regulate or down-regulate the immune system of hens, leading to approaches for inhibiting the colonization of the reproductive tissues by S.E. leading to a decreased incidence of contaminated shell eggs and reduction of exposure to consumers. </p>
Using the methods that we established in the first year of this project, we will examine the immune response of hens receiving different doses of S. E. in different phases of the hens= production cycle. We will also compare the immune response of hens at a time just after receiving the bacteria versus a designated time(s) after the inoculation.

Raybourne, Richard
DHHS/FDA - Center for Food Safety & Applied Nutrition
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