Effects of vitamin D3 on expression of defensins, Toll-like receptors, and vitamin D receptor in liver, kidney, and spleen of Silky Fowl

The expression of avian β-defensins (AvBDs), Toll-like receptors (TLRs), and vitamin D receptor (VDR) following in vivo vitamin D3 injection was studied. Healthy 90-day Silky Fowls were abdominally injected with vitamin D3 or untreated. Real-time PCR analyses revealed that injection of vitamin D3 significantly (P < 0.05) up-regulated the expression of TLRs (TLR2, TLR5), VDR, AvBDs (AVBD-6, GAL-1), and 24-hydroxylase (CYP24A1) in the tissues (liver, spleen, and kidney) at various times 8-24 h post injection. These results suggest that expression of VDR, AvBDs, and TLRs seems to be induced by vitamin D3 and it was concluded that the tissues expressing TLRs and VDR respond to vitamin D3 and in turn upregulate these tissues cellular functions to synthesize AvBDs. Intraperitoneal injection of vitamin D3 likely resulted in enhancing the expression of AvBDs, TLRs, and VDR, which providedinsight into factors important for the control of the innateimmune response in the chickens.