Expression of β-defensins in intestines of chickens injected with vitamin D3 and lipopolysaccharide.

The objective of this study was to evaluate the effect of vitamin D-3 (VD3) on the regulation of chicken intestinal beta-defensin genes under normal and lipopolysaccharides (LPS) conditions. Four treatment groups were used, including a negative control group, VD3-injection group, LPS-injection group, and both VD3-injection and LPS-injection group. At 4, 24, and 48 h post-injection, intestines were collected and RNA was isolated to measure the chicken beta-defensin genes with putative vitamin D responsive elements using quantitative polymerase chain reaction. Expressions of all 7 chicken beta-defensin genes was detectable in the intestines. Significant increases in GAL-6, -7 and -9 were found following LPS injection treatment at 4, 24, and 48 h post-injection, respectively, whereas VD3 injection did not affect the expression of any investigated genes under normal conditions. However, the expression of GAL-4, -5, -6, and -10 were synergistically upregulated by VD3 in combination with LPS. These results suggest that VD3 enhances the immune immunity during LPS challenge by inducing the expression of chicken beta-defensin genes when birds are exposed to immune stressors.