1a. Objectives (from AD-416)
To evaluate intestinal gene expression associated with dietary immunomodulation using phytonutrients.
1b. Approach (from AD-416)
Broiler chickens will be treated with various phytonutrients and their effects on avian immune response to mucosal pathogens will be evaluated using established disease parameters and various immunological assays.
3. Progress Report
With increasing regulation on the use of antibiotics in poultry production, there is a new thrust to find alternative drug-free strategies for growth promoting and disease control for farm animals. In order to best utilize the available information on the dietary immunomodulation of immunity for developing alternative disease control strategies in poultry, detailed studies on the immune mechanisms mediated by various plant-derived phytonutrients were carried out. In this reporting period, we evaluated the effects of organic extracts from milk thistle (Silybum marianum), turmeric (Curcuma longa), reishi mushroom (Ganoderma lucidum), and shiitake mushroom (Lentinus edodes) on innate immunity and tumor cell viability. Innate immunity was measured by lymphocyte proliferation and nitric oxide production by macrophages, and the inhibitory effect on tumor cell growth. In vitro culture of chicken spleen lymphocytes with extracts of milk thistle, turmeric, and shiitake and reishi mushrooms induced significantly higher cell proliferation compared with the untreated control cells. Stimulation of macrophages with extracts of milk thistle and shiitake and reishi mushrooms, but not turmeric, resulted in robust nitric oxide production to levels that were similar with those induced by recombinant chicken interferon-G. All extracts uniformly inhibited the growth of chicken tumor cells in vitro at the concentration of 6.3 through 100ug/ml. Finally, the levels of mRNAs encoding IL-1ß, IL-6, IL-12, IL-18, and TNFSF15 were enhanced in macrophages that were treated with extracts of turmeric or shiitake mushroom compared with the untreated control. These results document the immunologically-based enhancement of innate immunity in chickens by extracts of plants and mushrooms with known medicinal properties in vitro. Taken together, these results provide clear evidence for a synergistic effect of the different phytonutrients in promoting local protective immunity against coccidiosis. These observations also provide new information concerning the molecular mechanisms involved in dietary modulation in the chicken digestive tract that will facilitate the development of feed supplementation and novel dietary strategies to growth promoting effect and to host immune responses. This collaboration was monitored by regular meetings and progress reports.