高精料日粮对奶山羊乳腺组织NOD1炎性信号通路的影响

Effect of high-concentrate diet on NOD1 inflammatory signaling pathway in the mammary glands of lactating goats

本试验旨在研究高精料日粮对奶山羊乳腺组织NOD1炎性信号通路的影响与调控。选取18头泌乳中期的健康萨能奶山羊,试验前分别安装瘤胃瘘管和乳静脉血管插管,随机分成3组:饲喂精粗比为4∶6的低精料日粮作为对照组(LC);饲喂精粗比为6∶4的高精料日粮作为处理组(HC);饲喂高精料日粮并添加丁酸钠作为调控组(BHC),试验时间为20周。试验结束后采集瘤胃液、乳静脉血和乳腺组织样品用于后续的瘤胃pH值、乳静脉血中炎性因子浓度、乳腺组织中炎症相关基因m RNA和蛋白水平的检测。结果显示:一天内HC组的瘤胃pH值小于5.8持续4 h且显著低于LC组,表明亚急性瘤胃酸中毒(SARA)诱导成功;饲喂4 h后BHC组瘤胃pH值显著高于HC组而与LC组差异不显著,表明丁酸钠能够缓解瘤胃pH的持续降低。HC组乳静脉血中炎性细胞因子IL-1β、IL-6和TNF-α的浓度显著高于LC组,而BHC组的炎性细胞因子溶度显著低于HC组并与LC组无显著差异;与LC组和BHC组相比,HC组奶山羊乳腺组织炎症相关基因NOD1、RIP2、NF-κB、IL-1β、IL-6的表达量显著上调;NOD1、NF-κBp65、NF-κBpp65的蛋白表达水平和m RNA水平变化一致。结果表明,长期饲喂高精料日粮能够激活奶山羊乳腺组织的NOD1-NF-κB炎性信号通路,诱导乳腺炎症应答,日粮中添加丁酸钠可以一定程度地缓解乳腺组织的炎症反应。

The experiment was conducted to investigate the effect of high-concentrate diet on NOD1 inflammatory signaling pathway in the mammary glands of lactating goats. Before the experiment,eighteen dairy goats were fitted with rumen fistula and lacteal vein cannula and randomly divided into three groups： the first group was fed with a diet composed of 60% forage and 40% concentrate as a control（ LC）; the second group was fed with a diet composed of 40% forage and 60% concentrate as a treatment（ HC）; the third group was fed with an HC diet with sodium butyrate as a regulation（ BHC）,the experiment lasted for 20 weeks. At the end of the experiment,samples of rumen fluid,lacteal vein blood and mammary gland tissues were collected for the subsequent detection of rumen pH values,the concentration of pro-inflammatory cytokines in lacteal vein blood,m RNA and protein expression levels of genes involved in inflammation in the mammary glands.The results showed as follows： rumen pH in the HC group was significantly lower than the LC group and fallen below 5. 8 for 4 h/d,indicating that SARA was induced successfully; After 4 h feeding,rumen pH in the BHC group were significantly higher than that in the HC group and showed a significant difference with LC group,which indicated that sodium butyrate could alleviate the decrease of rumen pH. The concentration of inflammatory cytokines in lacteal vein blood,including IL-1β,IL-6 and TNF-α was significantly increased in the HC group,while these inflammatory cytokines in the BHC group was lower than those in the HC but showed no significant difference with the LC group.Compared with the LC and BHC groups,the m RNA expression of genes implicated in the inflammation in the HC group,including NOD1,RIP2,NF-κB,IL-1β and IL-6,was significantly increased,while the expression of several proteins,including NOD1,NF-κBp65 and NF-κBpp65,presented the same tendency as those of the target genes did. In conclusion,the long term feeding of HC diet activated NOD1-NF-κB inflammatory signaling pathway,resulting in inflammation in the mammary glands of mid-lactation dairy goats and sodium butyrate could alleviate the inflammation.