Vitamin A mediates many important biological functions in humans and animals. Presence of vitamin A receptors on immune system cells emphasizes their role in immune functions. To assess the effects of in ovo inoculation of vitamin A on the immune system of chicken embryos, 18 days old embryonated eggs were inoculated with 3 different concentrations of retinoic acid (the active form of vitamin A) at 30, 90, and 270 μmol/egg via the amniotic sac. After 6, 18, and 24 h, the spleen and bursa of the embryos were collected for RNA extraction and real-time polymerase chain reaction. The results were dose dependant. After 24 h, inoculation with 270 μmol/egg downregulated relative expression of interferon IFN-α, IFN-β, IFN-γ, interleukin (IL)-1β, IL-2, CXCLi2, IL-12, and IL-13 compared to control in the spleen, indicating an anti-inflammatory effect at this concentration. In comparison, 90 μmol/egg induced greater expressions of the above genes at the same timepoint compared to the 270 μmol. The results of this study indicate that in ovo inoculation of vitamin A can modulate immune functions of the chicken embryo, which might be beneficial for induction of immune responses by in ovo vaccines.

中文翻译：

---

卵内接种维生素 A 调节鸡胚胎免疫功能

维生素 A 介导人和动物的许多重要生物学功能。免疫系统细胞上维生素 A 受体的存在强调了它们在免疫功能中的作用。为了评估卵内接种维生素 A 对鸡胚胎免疫系统的影响，在18 天大的鸡蛋中接种 3 种不同浓度的视黄酸（维生素 A 的活性形式），浓度为 30、90 和 270 μmol/卵子通过羊膜囊。6、18 和 24 小时后，收集胚胎的脾脏和囊用于 RNA 提取和实时聚合酶链反应。结果是剂量依赖性的。24 h 后，接种 270 μmol/egg 下调干扰素IFN-α、IFN-β、IFN-γ 的相对表达，与脾脏中的对照相比，白细胞介素 (IL)-1β、IL-2、CXCLi2、IL-12和IL-13，表明在该浓度下具有抗炎作用。相比之下，与 270 μmol 相比，90 μmol/鸡蛋在同一时间点诱导了上述基因的更多表达。本研究结果表明，卵内接种维生素A可以调节鸡胚的免疫功能，这可能有利于卵内疫苗诱导免疫反应。