When both dietary (69 μg/kg feed) [32,34] and in ovo (2.4 μg) [28,39,40] sources of 25(OH)D3 were individually administered in normal or coccidiosis-infected poultry species, positive effects have been observed on the expressions of anti-inflammatory (IL-1β) and pro-inflammatory response (IL-10 and TGF-β4) genes. This evidence concerns the gene IL1B and coccidiosis.