USDA-ARS, US Dairy Forage Research Center, Madison, WI 53706, USA.
J Dairy Sci. 2010 Dec;93(12):5902-12. doi: 10.3168/jds.2010-3500.
The purpose of this study was to examine the stability and host specificity of a cow's ruminal bacterial community following massive challenge with ruminal microflora from another cow. In each of 2 experiments, 1 pair of cows was selected on the basis of differences in ruminal bacterial community composition (BCC), determined by automated ribosomal intergenic spacer analysis (ARISA), a culture-independent "community fingerprinting" technique. Each pair of cows was then subjected to a 1-time exchange of >95% of ruminal contents without changing the composition of a corn silage/alfalfa haylage-based TMR. In experiment 1, the 2 cows differed (P<0.01) in prefeed ruminal pH (mean = 6.88 vs. 6.14) and prefeed total VFA concentration (mean = 57 vs. 77 mM), averaged over 3 d. Following exchange of ruminal contents, ruminal pH and total VFA concentration in both cows returned to their preexchange values within 24h. Ruminal BCC also returned to near its original profile, but this change required 14 d for 1 cow and 61 d for the other cow. In experiment 2, the 2 other cows differed in prefeed ruminal pH (mean = 6.69 vs. 6.20) and total VFA concentration (mean = 101 vs. 136 mM). Following exchange of ruminal contents, the first cow returned to its preexchange pH and VFA values within 24h; the second cow's rumen rapidly stabilized to a higher prefeed pH (mean = 6.47) and lower prefeed VFA concentration (mean = 120 mM) that was retained over the 62-d test period. Both cows reached somewhat different BCC than before the exchange. However, the BCC of both cows remained distinct and were ultimately more similar to that of the preexchange BCC than of the donor animal BCC. The data indicate that the host animal can quickly reestablish its characteristic ruminal pH and VFA concentration despite dramatic perturbation of its ruminal microbial community. The data also suggest that ruminal BCC displays substantial host specificity that can reestablish itself with varying success when challenged with a microbial community optimally adapted to ruminal conditions of a different host animal.
本研究旨在探讨在大量接种另一头牛瘤胃微生物后，奶牛瘤胃细菌群落的稳定性和宿主特异性。在两项实验中，每对奶牛均根据瘤胃细菌群落组成（BCC）的差异进行选择，BCC 由自动核糖体基因间隔区分析（ARISA）确定，这是一种不依赖培养的“群落指纹”技术。每对奶牛均接受 1 次>95%的瘤胃液交换，同时不改变以玉米青贮/苜蓿干草青贮为基础的 TMR 的组成。在实验 1 中，2 头奶牛在预饲前瘤胃 pH（平均值为 6.88 对 6.14）和预饲前总 VFA 浓度（平均值为 57 对 77 mM）方面存在差异（P<0.01），这是 3 天的平均值。在交换瘤胃液后，2 头奶牛的瘤胃 pH 和总 VFA 浓度在 24 小时内均恢复到交换前的水平。瘤胃 BCC 也恢复到接近原始状态，但 1 头奶牛需要 14 天，另 1 头奶牛需要 61 天。在实验 2 中，另外 2 头奶牛在预饲前瘤胃 pH（平均值为 6.69 对 6.20）和总 VFA 浓度（平均值为 101 对 136 mM）方面存在差异。在交换瘤胃液后，第一头奶牛在 24 小时内恢复到交换前的 pH 和 VFA 值；第二头奶牛的瘤胃迅速稳定在较高的预饲前 pH（平均值为 6.47）和较低的预饲前 VFA 浓度（平均值为 120 mM），这一状态在 62 天的测试期内保持不变。2 头奶牛的 BCC 都与交换前有所不同。然而，2 头奶牛的 BCC 仍然存在明显的差异，最终与交换前的 BCC 比供体动物的 BCC 更为相似。数据表明，宿主动物可以迅速恢复其特征性的瘤胃 pH 和 VFA 浓度，尽管其瘤胃微生物群落受到了巨大的干扰。数据还表明，瘤胃 BCC 具有显著的宿主特异性，当受到最适应当宿主动物瘤胃条件的微生物群落的挑战时，它可以在不同程度上成功地恢复自己。
