Effect of in ovo feeding of folic acid on the folate metabolism, immune function and epigenetic modification of immune effector molecules of broiler
Effect of in ovo feeding of folic acid on the folate metabolism, immune function and epigenetic modification of immune effector molecules of broiler
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卵内饲喂叶酸对肉鸡叶酸代谢、免疫功能及免疫效应分子表观遗传修饰的影响
DOI：
10.1017/s0007114515004511
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发表时间：
2016-02-14
影响因子：
3.6
通讯作者：
Yang, Xiaojun
中科院分区：
文献类型：
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作者：
Li, Shizhao;Zhi, Lihui;Yang, Xiaojun
本研究旨在探讨卵内添加叶酸对肉仔鸡叶酸代谢、免疫功能的影响及其表观遗传修饰。将400枚（Cobb）种蛋随机分为4组（胚龄11 d时分别注射0、50、100和150 μg叶酸），孵化后将各处理出雏随机分为6个重复，每个重复12只鸡。结果表明，在卵内，100和150 μg叶酸注射提高了孵化率。在生长后期，150 µg组的平均日增重和饲料转化率增加。同时，在100和150 µg组中，观察到肝脏叶酸含量以及亚甲基四氢叶酸还原酶（d1和42）和甲硫氨酸合成酶还原酶（d21）的表达增加。随着叶酸水平的提高，肉鸡血清中IgG和IgM的含量以及血浆溶菌酶的活性沿着显著提高。在100和150 µg叶酸处理组中，IL-2和IL-4的脾脏表达水平上调，而IL-6的表达水平下调。此外，随着叶酸添加量的增加，IL-2和IL-4启动子中的组蛋白甲基化表现出H3 K4 m2的富集，但H3 K9 me 2的丢失。相比之下，在叶酸处理的IL-6启动子中观察到H3 K4 m2的减少和H3 K9 me 2的增加。此外，在卵内，150 μg叶酸注射改善了IL-2和IL-4启动子区域的染色质紧密性。研究结果表明，IOF添加150 µg叶酸可提高肉鸡的生长性能和叶酸代谢，并增强免疫功能与免疫基因表观遗传调控的关系，免疫基因表观遗传调控与染色质构象改变和启动子组蛋白甲基化有关。
Abstract This study was conducted to investigate the effect of in ovo feeding (IOF) of folic acid on the folate metabolism, immune function and the involved epigenetic modification of broilers. A total of 400 (Cobb) hatching eggs were randomly divided into four groups (0, 50, 100 and 150 µg injection of folic acid at embryonic age 11 d), and chicks hatched from each treatment were randomly divided into six replicates with 12 broilers/replicate after incubation. The results indicated that, in ovo, 100- and 150-µg folic acid injections improved the hatchability. The average daily gain and feed conversion ratio increased in the 150-µg group during the late growth stage. Simultaneously, in the 100- and 150-µg groups, an increase was observed in hepatic folate content and the expression of methylenetetrahydrofolate reductase (d1 and 42) and methionine synthase reductase (d21). IgG and IgM concentrations, as well as plasma lysozyme activity of broilers, showed a marked increase along with increasing folic acid levels. The splenic expression levels of IL-2 and IL-4 were up-regulated, whereas that of IL-6 was down-regulated, in the 100- and 150-µg folic acid treatment groups. In addition, histone methylation in IL-2 and IL-4 promoters exhibited an enrichment of H3K4m2 but a loss of H3K9me2 with the increased amount of folic acid additive. In contrast, a decrease in H3K4m2 and an increase in H3K9me2 were observed in the IL-6 promoter in folic acid treatments. Furthermore, in ovo, the 150-µg folic acid injection improved the chromatin tightness of the IL-2 and IL-4 promoter regions. Our findings suggest that IOF of 150 µg of folic acid can improve the growth performance and folate metabolism of broilers, and enhance the relationship between immune function and epigenetic regulation of immune genes, which are involved with the alterations in chromatin conformation and histone methylation in their promoters.