Vitamin A (VA) has pleiotropic effects on the immune system and is critical for mucosal immune function and intestinal lymphocyte trafficking. We hypothesized that oral VA supplementation of porcine epidemic diarrhea virus (PEDV)-infected pregnant gilts would enhance the gut-mammary gland-secretory IgA axis to boost lactogenic immunity and passive protection of nursing piglets against PEDV challenge. Gilts received daily oral retinyl acetate (30 000 IU) starting at gestation day 76 throughout lactation. At 3–4 weeks pre-partum, VA-supplemented (PEDV + VA) and non-supplemented (PEDV) gilts were PEDV or mock inoculated (mock + VA and mock, respectively). PEDV + VA gilts had decreased mean PEDV RNA shedding titers and diarrhea scores. To determine if lactogenic immunity correlated with protection, all piglets were PEDV-challenged at 3–5 days post-partum. The survival rate of PEDV + VA litters was 74.2% compared with 55.9% in PEDV litters. Mock and mock + VA litter survival rates were 5.7% and 8.3%, respectively. PEDV + VA gilts had increased PEDV IgA antibody secreting cells and PEDV IgA antibodies in serum pre-partum and IgA+β7+ (gut homing) cells in milk post piglet challenge compared with PEDV gilts. Our findings suggest that oral VA supplementation may act as an adjuvant during pregnancy, enhancing maternal IgA and lactogenic immune protection in nursing piglets.

中文翻译：

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口服维生素A补充猪流行性腹泻病毒感染的后备母猪增强IgA和哺乳仔猪的乳原性免疫保护

维生素A（VA）对免疫系统具有多效作用，对于粘膜免疫功能和肠道淋巴细胞运输至关重要。我们假设口服猪流行性腹泻病毒（PEDV）感染的后备小猪的VA补充将增强肠-乳腺-分泌性IgA轴，以增强泌乳原性免疫力和对PEDV激发的哺乳仔猪的被动保护。小母猪在整个哺乳期的第76天开始接受每日口服乙酸视黄酯（30000 IU）。产前3至4周，分别给PE补胎或模拟接种（补充量）模拟和补充VA补充后备母猪（PEDV + VA）和非补充后备母猪（PEDV）。PEDV + VA后备母猪的平均PEDV RNA脱落效价和腹泻评分降低。为了确定泌乳原性免疫是否与保护相关，所有的仔猪在产后3-5天都受到PEDV的攻击。PEDV + VA凋落物的存活率为74.2％，而PEDV凋落物的存活率为55.9％。模拟和模拟+ VA垃圾存活率分别为5.7％和8.3％。与PEDV母猪相比，PEDV + VA母猪在仔猪攻击后血清中的产前和DVg IgA抗体分泌细胞增加，而PEDV IgA抗体在血清和IgA +β7+（肠归巢）细胞中增加。我们的发现表明，口服VA补充剂可在怀孕期间作为佐剂，增强母猪IgA和哺乳仔猪的乳原性免疫保护作用。与PEDV母猪相比，PEDV + VA母猪在仔猪攻击后血清中的产前和DVg IgA抗体分泌细胞增加，而PEDV IgA抗体在血清和IgA +β7+（肠归巢）细胞中增加。我们的研究结果表明，口服VA补充剂可在怀孕期间作为佐剂，增强母猪IgA和哺乳仔猪的乳原性免疫保护作用。与PEDV母猪相比，PEDV + VA母猪在仔猪攻击后血清中的产前和DVg IgA抗体分泌细胞增加，而PEDV IgA抗体在血清和IgA +β7+（肠归巢）细胞中增加。我们的发现表明，口服VA补充剂可在怀孕期间作为佐剂，增强母猪IgA和哺乳仔猪的乳原性免疫保护作用。