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United States Department of Agriculture

Agricultural Research Service

2010 Annual Report

1a.Objectives (from AD-416)
1. To evaluate effects of Lactobacillus acidophilus NP51 on host immune response. 2. To evaluate effects of NP51 on the prevention of MAP infection. 3. To evaluate effects of NP51 on the treatment of MAP infection.

1b.Approach (from AD-416)
Mice will be fed NP51 before and after challenge with MAP to ascertain the effectiveness in prevention or treatment of the infection and colonization of target tissues such as spleen, ileum, and mesenteric lymph nodes. The host response to NP51 will be determined by evaluation of cytokine induction alone and in tandem with MAP infection.

3.Progress Report

This collaborative research project encompasses measures to ensure animal health through the control and management of the disease by improving knowledge of host immunity during infection. Feeding the probiotic, NP51, will allow us to determine if altering the gut ecology of the host will prevent colonization of Mycobacterium avium subspecies paratuberculosis (MAP) in the small intestine and associated tissues. As part of the study, we will attempt to determine if the mechanism of action of the probiotic is correlated with altered host immunity, both in the peripheral blood and at the site of infection. Gaining a further understanding into the host immune responses to MAP infection will add insight into the pathogenesis of this bacterium, providing us with information that will be helpful in potential treatments for infection in dairy cattle. Results from the first mouse study evaluating the appropriate dose of the probiotic to feed mice were analyzed. Feeding the highest level of probiotic did not affect the health of the mice. A second study was completed in which the probiotic was fed to mice prior to challenge with live MAP. Data demonstrate that the probiotic was very effective in preventing colonization of MAP in tissues of mice. In addition, the probiotic appeared to enhance T cell-mediated immunity in MAP-infected mice. These data will be useful in determining if probiotics can be used for the treatment and prevention of paratuberculosis in cattle. Progress will be monitored by associated parties via monthly phone calls and/or e-mails and meetings every 2-3 months.

Last Modified: 11/24/2015
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