title: The immunomodulatory effect of vitamin D in chickens is dose-dependent and influenced by calcium and phosphorus levels.
abstract: Vitamin D requirement is estimated to be higher than recommended values for the first two weeks of a broiler chicken's life, and is heavily dependent on the concentrations of Ca and P in the diet. There are data indicating the beneficial effect of higher vitamin D levels on performance and overall health of the chickens. However, data on the role of higher vitamin D levels on the innate immune response of chickens are limited. Therefore, in the current study, we examined the effect of higher doses of vitamin D supplementation on the innate immune response in broiler chickens receiving optimal or calcium (Ca) and phosphorus (P) deficient diets. Three hundred Ross-308 male broiler chicks were randomly allocated into 60 cages with 5 birds per cage in a 3 × 2 factorial design with three levels of vitamin D and two levels of Ca/P with each experimental diet fed to 10 cages (10 replicates). Quantitative reverse transcription PCR (n = 5) was used to assess Toll-like receptor (TLR2b and 4), cytokine/chemokine (IL-12, IFN-γ, IL-10, IL-4, IL-13, IL-18, CxCLi2) and cathelicidin (CATH1, CATHB1, CATH3) transcription levels in peripheral blood mononuclear cells (PBMCs), spleen, and bursa of Fabricius. Vitamin D supplementation of the Ca and P deficient diet considerably augmented transcription of TLR2b, TLR4, CATH1, and CATHB1 and predominantly Th2 cytokines in spleen. Supplementation of the control diet with vitamin D downregulated TLR4 transcription, and dose-dependently increased CATH1, CATHB1, Th1, and Th2 cytokine transcription (Th2>Th1). All diets downregulated CATH3 transcription. In conclusion, vitamin D or its derivative 25-OH-D3both have a robust immunomodulatory property with a more favorable Th2 response, while at the same time enhancing observed Th2 cytokine responses under both optimal and lower Ca and P inclusion levels in the diets of broiler chickens.
authors.affiliation: Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, PEI, Canada, C1A 3P4 jrodriguez@upei.ca.
authors.forename: J C
authors.initials: JC
authors.lastname: Rodriguez-Lecompte
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada N1G 2W1.
authors.forename: A
authors.initials: A
authors.lastname: Yitbarek
authors.affiliation: Department of Infectious Diseases & Immunology, Division Molecular Host Defense, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Cuperus
authors.affiliation: Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada R3T 2N2.
authors.forename: H
authors.initials: H
authors.lastname: Echeverry
authors.affiliation: Department of Infectious Diseases & Immunology, Division Molecular Host Defense, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: van Dijk
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D030161:Avian Proteins / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000172:deficiency; D002136:Calcium, Dietary / Q000378:metabolism; D002645:Chickens / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004032:Diet / Q000662:veterinary; D004305:Dose-Response Relationship, Drug; D007113:Immunity, Innate; D008297:Male; D010758:Phosphorus / Q000172:deficiency; D016226:Phosphorus, Dietary / Q000378:metabolism; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D014807:Vitamin D / Q000008:administration & dosage / Q000494:pharmacology*; D014815:Vitamins / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D030161:Avian Proteins; D002136:Calcium, Dietary; D016226:Phosphorus, Dietary; D014815:Vitamins; D014807:Vitamin D; D010758:Phosphorus; D002118:Calcium
keywords: TLRs; Vitamin D; antimicrobial peptides; cathelicidins; cytokines