Effects of Vitamin D (Ergocalciferol) and D (Cholecalciferol) on Atlantic Salmon () Primary Macrophage Immune Response to subsp. Infection.

Vitamin D (ergocalciferol) and vitamin D (cholecalciferol) are fat-soluble secosteroid hormones obtained from plant and animal sources, respectively. Fish incorporates vitamin D and D through the diet. In mammals, vitamin D forms are involved in mineral metabolism, cell growth, tissue differentiation, and antibacterial immune response. Vitamin D is an essential nutrient in aquafeeds for finfish. However, the influence of vitamin D on fish cell immunity has not yet been explored. Here, we examined the effects of vitamin D and vitamin D on primary macrophage immune response to subspecies infection under conditions. We determined that high concentrations of vitamin D (100,000 ng/ml) and D (10,000 ng/ml) affect the growth of and decrease the viability of primary macrophages. In addition, we determined that primary macrophages pre-treated with a biologically relevant concentration of vitamin D for 24 h showed a decrease of infection. In contrast, vitamin D did not influence the antibacterial activity of the macrophages infected with . Vitamin D and D did not influence the expression of canonical genes related to innate immune response. On the other hand, we found that up-regulated the expression of several canonical genes and suppressed the expression of () gene, involved in neutrophil recruitment. Primary macrophages pre-treated for 24 h with vitamin D counteracted this immune suppression and up-regulated the transcription of . Our results suggest that vitamin D affects attachment to the primary macrophages, and as a consequence, the invasion decreased. Moreover, our study shows that the positive effects of vitamin D on fish cell immunity seem to be related to the innate immunity mechanisms. We did not identify positive effects of vitamin D on fish cell immunity. In conclusion, we determined that the inactive form of vitamin D, cholecalciferol, induced anti-bacterial innate immunity pathways in Atlantic salmon primary macrophages, suggesting that its utilization as a component of a healthy aquafeed diet in Atlantic salmon could enhance the immune response against .