Effects of Vitamin A and K3 on Immune Function and Intestinal Antioxidant Capacity of Aged Laying Hens

ABSTRACT This study was conducted to investigate effects of vitamin A (VA) and vitamin K3 (VK3) on immune function and intestinal antioxidant capacity of aged laying hens. In a 3 × 3 factorial arrangement, the diets of 1080 Roman Pink laying hens (87 weeks old) was formulated with deficient, adequate and excess VA and VK3, including 0, 7000 and 14000 IU/kg VA and 0, 2.0 and 4.0 mg/kg VK3 for 8 weeks. Interactive effects between VA and VK3 were observed that VA and VK3 decreased the splenetic mRNA expression of inducible nitric oxide synthase (iNOS) and tumour necrosis factor α (TNF-α), but increased the plasma immunoglobulin G (IgG) content and jejunal mRNA expression of nuclear factor-like 2 (Nrf2). Hens fed adequate or excess VA had higher spleen index, mRNA expression of interleukin-10 (IL-10) in spleen, sIgA content, catalase (CAT), glutathione peroxidase and total dismutase (T-SOD) activity, and mRNA expression of polymeric immunoglobulin receptor (pIgR) in jejunum and lower mRNA expression of IL-1β in jejunum and iNOS, TNF-α in spleen. Furthermore, adequate or excess VK3 significantly increased plasma IgG content, the CAT, T-SOD and total antioxidant capacity activities, up-regulated the mRNA expression of pIgR, Nrf2, SOD1 and CAT in jejunum and down-regulated the mRNA expression of iNOS and TNF-α in spleen. In conclusion, dietary addition of adequate VA (7000 IU/kg) and VK3 (2.0 mg/kg) improved the immune function and intestine antioxidant capacity of aged laying hens and excess levels did not exhibit superior effects.

摘要 本研究旨在探究维生素A（vitamin A，VA）与维生素K3（vitamin K3，VK3）对老龄产蛋鸡免疫功能及肠道抗氧化能力的影响。试验采用3×3因子设计，将1080只87周龄罗曼粉壳产蛋鸡的日粮分别设置缺乏、适宜、过量三个水平的VA和VK3，其中VA添加梯度为0、7000、14000 IU/kg，VK3添加梯度为0、2.0、4.0 mg/kg，试验周期为8周。
结果显示，VA与VK3存在交互作用：二者可下调脾脏诱导型一氧化氮合酶（inducible nitric oxide synthase，iNOS）与肿瘤坏死因子α（tumour necrosis factor α，TNF-α）的mRNA表达水平，同时上调血浆免疫球蛋白G（immunoglobulin G，IgG）含量以及空肠核因子样2（nuclear factor-like 2，Nrf2）的mRNA表达水平。
饲喂适宜或过量VA的产蛋鸡，其脾脏指数、脾脏白细胞介素10（interleukin-10，IL-10）mRNA表达水平、分泌型免疫球蛋白A（secretory immunoglobulin A，sIgA）含量、过氧化氢酶（catalase，CAT）、谷胱甘肽过氧化物酶活性及总歧化酶（total dismutase，T-SOD）活性，以及空肠多聚免疫球蛋白受体（polymeric immunoglobulin receptor，pIgR）mRNA表达水平均显著升高，而空肠白细胞介素1β（interleukin-1β，IL-1β）与脾脏iNOS、TNF-α的mRNA表达水平显著降低。
此外，适宜或过量VK3可显著提升血浆IgG含量、CAT及T-SOD活性与总抗氧化能力，上调空肠pIgR、Nrf2、SOD1及CAT的mRNA表达，并下调脾脏iNOS与TNF-α的mRNA表达。
综上，日粮添加适宜水平的VA（7000 IU/kg）与VK3（2.0 mg/kg）可改善老龄产蛋鸡的免疫功能与肠道抗氧化能力，过量添加未展现出更优效果。