载锌凹凸棒石黏土对瘤胃体外发酵细菌多样性的影响（英文）

Effect of zinc-bearing palygorskite on rumen bacterial diversity in vitro

【目的】研究载锌凹凸棒石黏土对瘤胃体外发酵细菌多样性的影响。【方法】本试验采用离子交换法制备载锌凹凸棒石黏土,利用16S rDNA测序技术分析了载锌凹凸棒石黏土对奶牛瘤胃体外发酵细菌菌群和多样性的影响。【结果】研究共获得1490959个有效序列和87662个OTUs。测序结果表明,与对照组相比,试验Ⅳ组中的细菌多样性在体外发酵24 h时提高,试验Ⅳ组中的细菌丰度在体外发酵48 h时提高。细菌菌群组成分析表明,60个样本中的优势菌门主要是厚壁菌门、拟杆菌门、变形菌门和黏胶球形菌门。与对照组相比,各试验组的厚壁菌门在体外发酵24 h和48 h时均显著增加(P<0.05),试验Ⅳ组中拟杆菌门在发酵48 h时显著降低(P<0.05);60个样本中共获得124个细菌菌属,其中对照组与试验组中普氏菌属含量均没有显著变化(P>0.05)。在体外发酵48 h时,试验Ⅳ组中密螺旋体属含量与对照组相比显著增加(P<0.05),而食物谷菌属和假丁酸弧菌属含量与对照组相比均显著降低(P<0.05)。【结论】载锌凹凸棒石黏土对奶牛瘤胃体外发酵中细菌多样性产生一定影响,其影响随发酵时间和添加剂量而不同。

[Objective] The aim of this experiment was to study the effects of zinc-bearing palygorskite （Zn-Pal） on rumen bacterial diversity in vitro. [Methods] We prepared Zn-Pal by the ion-exchange, and evaluated the compositions of bacterial communities in 60 samples based on 16S rDNA genes. [Results] We obtained a total of 1490959 effective sequences and 87662 OTUs. The bacterial diversity in the treatment IV group increased at 24 h, and the abundance of the treatment IV group increased at 48 h. Bacterial community composition analysis shows that the dominant phyla were Bacteroidetes, Firmicutes, Proteobacteria and Lentisphaerae. Compared with the control group, Firmicutes in treatment groups significantly increased （P〈0.05） at 24 h and 48 h, whereas Bacteroidetes in the treatment IV group was decreased （P〈0.05） at 48 h. At the genus level, the sequences could be assigned to 124 different genera. The content of Prevotella had no significant difference between the control and treatments. The relative abundance of Treponema in the treatment IV group was significantly higher at 48 h than in the control group （P〈0.05）, whereas the relative abundance of Victivallis and Pseudobutyrivibrio in treatment IV was lower. [Conclusion] Zn-Pal may affect rumen fluid bacterial diversity in dairy cows, and the degrees of this influence varied with the dose and time of Zn-Pal.