Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
Poult Sci. 2013 Jan;92(1):105-13. doi: 10.3382/ps.2012-02579.
Folic acid plays a key role in nucleic acids and protein synthesis, and has been associated with anti-inflammatory effects in LPS-induced infections. To this end, a study was conducted to investigate the effects of dietary folic acid (FA) supplementation in older laying hens (58 to 66 wk of age) challenged with Escherichia coli lipopolysaccharide (LPS). A total of 24 Shaver White laying hens at 58 wk were fed 2 diets. The diets were wheat-soybean-based, with either 0 or 4 mg of supplemental FA per kg of diet. After 8 wk of feeding and at 66 wk, the hens were injected intravenously with 8 mg of LPS or saline per kg of BW. Four hours after injection, blood was collected and hens were euthanized to obtain spleen and cecal tonsils. The T cell subsets in the blood and the spleen (CD4+ and CD8+), total IgG, and biochemical constituents (total protein, albumin, globulin, and fibrinogen) were not influenced (P > 0.05) by dietary FA supplementation. However, LPS injection decreased (P < 0.05) biochemical constituents, CD4+, and CD8+ cells in the blood, whereas CD4+:CD8+ ratio and total IgG increased (P < 0.05), and fibrinogen was not influenced. Gene expression in the spleen and cecal tonsils was not influenced by dietary FA supplementation except a diet × challenge interaction for interleukin (IL)-8 in the spleen; IL-8 decreased in FA-fed hens that were treated with LPS. Also, FA supplementation decreased the expression of IL-8 in cecal tonsils. Relative to saline-injected hens, expression of IL-1β, interferon-γ, and IL-10 increased in the LPS-injected hens in the spleen and cecal tonsils, IL-8 increased in LPS-injected hens only in the cecal tonsils, whereas Toll-like receptor 4, IL-4, IL-17, and IL-18 increased in the LPS-injected hens only in the spleen; however, LPS decreased expression of IL-13 in the cecal tonsils. In conclusion, FA did not affect inflammatory responses in older laying hens; more studies are required to investigate possible protective effects of FA in laying hens.
叶酸在核酸和蛋白质合成中起着关键作用，并与 LPS 诱导的感染中的抗炎作用有关。为此，进行了一项研究，以调查在大肠杆菌脂多糖 (LPS) 攻毒的老年产蛋鸡（58 至 66 周龄）中补充膳食叶酸 (FA) 的效果。共有 24 只 58 周龄的 Shavers 白产蛋鸡饲喂 2 种日粮。日粮以小麦-豆粕为基础，每公斤日粮分别添加 0 或 4 毫克的补充 FA。饲喂 8 周后，在 66 周龄时，每公斤 BW 给母鸡静脉注射 8 毫克 LPS 或生理盐水。注射后 4 小时，采集血液，处死母鸡以获得脾脏和盲肠扁桃体。血液中的 T 细胞亚群（CD4+和 CD8+）、总 IgG 以及生化成分（总蛋白、白蛋白、球蛋白和纤维蛋白原）不受日粮 FA 补充的影响（P＞0.05）。然而，LPS 注射降低了血液中生化成分、CD4+和 CD8+细胞（P＜0.05），而 CD4+/CD8+比值和总 IgG 增加（P＜0.05），纤维蛋白原不受影响。除了脾内白细胞介素 (IL)-8 的日粮 × 攻毒互作外，日粮 FA 补充对脾和盲肠扁桃体的基因表达没有影响；在接受 LPS 处理的 FA 喂养母鸡中，IL-8 减少。此外，FA 补充降低了盲肠扁桃体中 IL-8 的表达。与注射生理盐水的母鸡相比，在 LPS 注射的母鸡中，脾脏和盲肠扁桃体中的 IL-1β、干扰素-γ 和 IL-10 表达增加，仅在盲肠扁桃体中的 IL-8 增加，而仅在脾脏中的 Toll 样受体 4、IL-4、IL-17 和 IL-18 增加；然而，LPS 降低了盲肠扁桃体中的 IL-13 表达。总之，FA 不影响老年产蛋鸡的炎症反应；需要进一步研究 FA 对产蛋鸡的可能保护作用。
