Vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) are fat-soluble secosteroid hormones obtained from plant and animal sources, respectively. Fish incorporates vitamin D2 and D3 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 D2 and vitamin D3 on Salmo salar primary macrophage immune response to A. salmonicida subspecies salmonicida infection under in vitro conditions. We determined that high concentrations of vitamin D2 (100,000 ng/ml) and D3 (10,000 ng/ml) affect the growth of A. salmonicida and decrease the viability of S. salar primary macrophages. In addition, we determined that primary macrophages pre-treated with a biologically relevant concentration of vitamin D3 for 24 h showed a decrease of A. salmonicida infection. In contrast, vitamin D2 did not influence the antibacterial activity of the S. salar macrophages infected with A. salmonicida. Vitamin D2 and D3 did not influence the expression of canonical genes related to innate immune response. On the other hand, we found that A. salmonicida up-regulated the expression of several canonical genes and suppressed the expression of leukocyte-derived chemotaxin 2 (lect-2) gene, involved in neutrophil recruitment. Primary macrophages pre-treated for 24 h with vitamin D3 counteracted this immune suppression and up-regulated the transcription of lect-2. Our results suggest that vitamin D3 affects A. salmonicida attachment to the S. salar primary macrophages, and as a consequence, the A. salmonicida invasion decreased. Moreover, our study shows that the positive effects of vitamin D3 on fish cell immunity seem to be related to the lect-2 innate immunity mechanisms. We did not identify positive effects of vitamin D2 on fish cell immunity. In conclusion, we determined that the inactive form of vitamin D3, 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 A. salmonicida.

中文翻译：

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维生素D2（麦角钙化醇）和D3（胆固醇钙化醇）对大西洋鲑（Salmo salar）初级巨噬细胞对鲑鱼气单胞菌亚种免疫反应的影响。沙门氏菌感染。

维生素D2（麦角钙化固醇）和维生素D3（胆固醇钙化固醇）分别是从植物和动物来源获得的脂溶性类固醇激素。鱼在饮食中含有维生素D2和D3。在哺乳动物中，维生素D形式参与矿物质代谢，细胞生长，组织分化和抗菌免疫反应。维生素D是有鳍鱼类水产饲料中的必需营养素。但是，尚未研究维生素D对鱼细胞免疫的影响。在这里，我们检查了维生素D2和维生素D3在体外条件下对Salmo salar初级巨噬细胞对沙门氏菌亚种沙门氏菌感染的免疫反应的影响。我们确定高浓度的维生素D2（100,000 ng / ml）和D3（10,000 ng / ml）影响鲑鱼曲霉的生长并降低S.的活力。撒拉人初级巨噬细胞。此外，我们确定用生物学上相关浓度的维生素D3预处理24小时的原代巨噬细胞显示出鲑鱼曲霉感染的减少。相比之下，维生素D2并没有影响被鲑鱼沙门氏菌感染的沙门氏菌巨噬细胞的抗菌活性。维生素D2和D3不会影响与先天免疫反应有关的规范基因的表达。另一方面，我们发现沙门氏菌可以上调几个规范基因的表达，并抑制白细胞衍生的趋化因子2（lect-2）基因的表达，这与嗜中性白细胞的募集有关。维生素D3预处理24小时的原代巨噬细胞抵消了这种免疫抑制作用，并上调了lect-2的转录。我们的结果表明维生素D3影响A。沙门氏菌附着于沙门氏菌初级巨噬细胞，结果，沙门氏菌的入侵减少。此外，我们的研究表明，维生素D3对鱼细胞免疫的积极作用似乎与lect-2先天免疫机制有关。我们没有发现维生素D2对鱼细胞免疫的积极作用。总之，我们确定了维生素D3的非活性形式胆钙化固醇在大西洋鲑鱼初级巨噬细胞中诱导了细菌的先天免疫途径，这表明将其用作健康鲑鱼饲料中的一部分可以增强针对A的免疫反应鲑科 我们的研究表明，维生素D3对鱼细胞免疫的积极作用似乎与lect-2先天免疫机制有关。我们没有发现维生素D2对鱼细胞免疫的积极作用。总之，我们确定了维生素D3的非活性形式胆钙化固醇在大西洋鲑鱼初级巨噬细胞中诱导了细菌的先天免疫途径，这表明将其用作健康鲑鱼饲料中的一部分可以增强针对A的免疫反应鲑科 我们的研究表明，维生素D3对鱼细胞免疫的积极作用似乎与lect-2先天免疫机制有关。我们没有发现维生素D2对鱼细胞免疫的积极作用。总之，我们确定了维生素D3的非活性形式胆钙化固醇在大西洋鲑鱼初级巨噬细胞中诱导了细菌的先天免疫途径，这表明将其用作健康鲑鱼饲料中的一部分可以增强针对A的免疫反应鲑科