应用DGGE分析秸秆日粮对奶牛瘤胃细菌群落的影响

【目的】通过与苜蓿日粮比较，揭示秸秆日粮模式下瘤胃固液相细菌群落的独特结构。【方法】选择12头健康且体重相似的装有永久瘤胃瘘管的中国荷斯坦奶牛，分别饲喂以玉米秸秆（CS）和苜蓿、羊草、青贮玉米三者混合物（MF）为粗饲料组成的日粮，正饲期第13周连续3 d分12个时间点采集瘤胃固、液相内容物样品。提取微生物DNA后，利用PCR结合变性梯度凝胶电泳技术（DGGE）分析细菌群落结构，并进行聚类分析及差异条带的测序分析。【结果】与MF组相比，CS组奶牛瘤胃固、液相细菌DGGE图谱条带的数目和光密度均有一定差异，两处理组都各有一些稍显优势的条带，CS组优势条带要少于MF组。与MF组相比，CS组液相细菌的香浓多样性指数无差异（P＞0.05），固相细菌香浓多样性指数显著降低（P＜0.01）；通过对差异条带进行测序，发现与MF组相比，CS组中瘤胃细菌Prevotella sp.、Acetivibrio ethanolgignens和Clostridium sp.减少，并且大量来源于Bacteroidetes、Firmicutes、Tenericutes和Proteobacteria等菌门的未培养细菌有所变化。【结论】秸秆日粮条件下奶牛瘤胃存在独特的细菌群落结构，细菌多样性较低。

Effect of Corn Straw Diet on Diversity of the Bacterial Community in the Rumen of Dairy Cows Analyzed by DGGE

【Objective】The purpose of this study is to reveal the unique rumen bacterial community under the diet of the corn straw compared to the diet of alfalfa fed to dairy cows. 【Method】Twelve healthy Chinese Holstein dairy cows with permanent rumen cannula and similar live weight were assigned to two treatments, corn straw diet (CS) and mixed forage (alfalfa, Chinese wildrye hay and silage maize) diet (MF). The solid and liquid fractions of rumen digesta were collected for the successive three days on the 13th week of the experiment. Total DNA was extracted and analyzed by denaturing gradient gel electrophoresis (DGGE) with subsequent cluster and sequence analysis. 【Result】 DGGE profiles showed the quantity and optimal density of the DGGE bands in CS group were different from MF group. Some bands from CS group were less compared to MF group. Shannon-Weiner index showed no difference (P＞0.05) between the two groups for liquid-associated bacteria, but it was significantly lower (P＜0.01) in CS group than that in MF group for solid-associated bacteria. Analysis from sequences showed that the diversity of Prevotella sp., Acetivibrio ethanolgignens and Clostridium sp. decreased in CS group. The other uncultured bacteria belonging to the phylum Bacteroidetes, Firmicutes, Tenericutes and Proteobacteria had some changes between the two groups.【Conclusion】 There are unique bacterial community and low diversity in the rumen of dairy cows fed with diet of corn straw.