Effects of Different Immune Status on the Variation of Intestinal Microflora Community in Broiler Chickens(Gallus gallus) | 免疫应激对肉鸡肠道微生物区系的影响

chinois. 微生物区系的平衡是确保肠道健康的重点，本研究对不同免疫状态下肉仔鸡消化道内微生物变化规律进行了研究。选用180只AA肉公鸡随机分4个处理，每个处理5个重复，每个重复9只肉公鸡。实验分为无免疫组、常规免疫组、免疫亢进和免疫抑制4个处理组。于21、28、35和42日龄肠段的内容物，提取总DNA，并以此为模板获得反映肠道微生物群落结构特征的肠杆菌基因间重复序列-PCR(ERIC-PCR)指纹图谱，比较各DNA样品指纹图谱的相似性指数。ERIC-PCR扩增产物大部分为200~2 000 bp的基因片段，聚类分析显示，各日龄阶段，处理组间十二指肠细菌种群结构的相似性最高(75%)，其次是盲肠(40%)，回肠(39%)和空肠(38%)的相似性较低。图谱的条带数目为十二指肠＞回肠＞盲肠＞空肠。28和35日龄，十二指肠和空肠脂多糖(LPS)组条带都低于21日龄，而回肠和盲肠的未见显著变化。21日龄，回肠环磷酰胺(CYP)组的条带低于其他处理组。不同免疫状态影响回肠、空肠和盲肠道微生物区系，42日龄，不同免疫状态对微生物数量和种群的影响不明显。

anglais. It focuses on the intestinal health that balances in microbial flora. The objective of this study was to examine the variation of gastrointestinal tract microflora in broilers raised under different immune status. Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) was conducted to evaluate this effect in broilers. Treatments consisted of a negative control, general vaccination, lipopolysaccharide(LPS) + general vaccination and cyclophosphamide(CYP )+ general vaccination. On the age of 21, 28, 35 and 42 d, digesta of duodenum, jejunum, ileum and cecum were collected to assay for gut microflora. The results showed that the DNA fingerprinting of ERIC-PCR had high stability and repetition. The molecular weights of gene fragment were almost from 200 to 2 000 bp after ERIC-PCR amplification. Different immune stress affected gut microflora to different degrees, and as age varied, the dominant microflora correspondingly changed. The diversity of cecal microflora was mostly obvious in LPS+ general vaccination treatment and CYP+ general vaccination treatment. In the present study, based on cluster analysis, the similarity of gut microflora in negative control was relatively stable, and among all treatments, the similarity of duodenal microflora was up to 75%, followed by cecum(40%), jejunum(38%) and ileum(39%). Under different immune status, between LPS group and no vaccination group, the microbial number and distribution in jejunum were different, but there were no significant difference in ileum and cecum between LPS group and CYP group.