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, ARS scientists investigated the immune enhancing effect of two phytonutrient mixtures, carvacrol, cinnamaldehyde, and Capsicum oleoresin (VAC) and Capsicum oleoresin and turmeric oleoresin (MC) on the local and systemic immune responses of the host following immunization of chickens with an Eimeria recombinant protein. Bird experiments showed that chickens fed from hatch with diets supplemented with VAC or MC and immunized subcutaneously with profilin vaccine at 7 days post-hatch showed increased body weight gains, although fecal oocyst shedding was not affected. Immunized chickens given the MC-supplemented diet displayed increased anti-profilin antibody levels and greater profilin-induced lymphocyte proliferation compared with non-supplemented controls. Further, immunized chickens fed the MC-supplemented diet had reduced levels of inflammatory cytokines, interferon gamma and interleukin 6 compared with non-supplemented controls. Finally, immunized chickens fed the MC-supplemented diet exhibited increased percentages of several classes of lymphocytes compared with non-supplemented controls. These studies clearly show that dietary phytonutrients exerts immune enhancement of vaccination response and promote gut health in broiler chickens.