Submitted to: Veterinary Immunology International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 6/13/2007
Publication Date: 8/13/2007
Citation: Eicher, S.D., Lin, T., Wu, C., Applegate, T., Patterson, J. 2007. Spleen cell TLR7 and iNOS RNA expression of coconut meal fed broilers following IBDV challenge [abstract]. In: Proceedings of the 8th Veterinary Immunology International Symposium. p. 76.
Technical Abstract: Coconut meal is immunomodulating in part because of its lauric acid content. Whether this dietary immunomoulator can enhance innate immunity of chickens to circumvent or combat a viral challenge has not been studied. Chickens are frequently raised in confinement buildings, but a growing trend for pasture raised birds is evident. The objective of this work was to determine the effect of coconut meal on innate immune function of pasture and confinement raised chickens with and without Infectious Bursal Disease (IBDV). Sixty day-old broiler chickens were assigned to either a coconut meal diet or a standard corn/soy diet containing antibiotics in each of the two studies. The first study was conducted with pasture raised broilers, and the second with broilers in typical confinement housing. After receiving the diets for 4 weeks, birds were challenged orally with 4.1 x 103 EID50 IBDV virus. Six chickens from each dietary group were euthanized at 0, 24, and 96 h after challenge, and spleens were harvested for determination of toll-like receptor (TLR) 7 and inducible nitric oxide synthase (iNOS) RNA expression. Toll-like receptor 7 increased (P < 0.05) following the viral challenge in both pasture raised and confinement raised chickens, and was greater (P < 0.05) for the coconut diet at 96 h. The expression of iNOS in the spleen cells did not change in the confinement raised birds (P > 0.10), but was initially greater in the pasture raised birds, suggesting exposure to bacterial pathogens in the environment. iNOS decreased by 1.67 fold by 96 h compared to 0 h for birds fed the corn/soy diet and decreased by more than 10,000 fold for coconut meal fed birds. iNOS was less (P < 0.05) in the birds fed the coconut diet than for the corn/soy fed birds at 96 h post challenge. These data show the viral challenge enhanced TLR7 expression by 96 h after challenge, and was affected by dietary treatment by that time. Expression of iNOS was variably affected by the viral challenge in birds raised under different conditions and fed different diets. These results will be useful for producers in determining the risks and benefits when seeking possible immune modulators to replace antibiotics.