Individual animal variability in ruminal bacterial communities and ruminal acidosis in primiparous Holstein cows during the periparturient period
Individual animal variability in ruminal bacterial communities and ruminal acidosis in primiparous Holstein cows during the periparturient period
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DOI：
10.3168/jds.2012-5772
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发表时间：
2012-11-01
影响因子：
3.5
通讯作者：
Beauchemin, K. A.
中科院分区：
文献类型：
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作者：
Mohammed, R.;Stevenson, D. M.;Beauchemin, K. A.
本研究的目的是调查个体奶牛的瘤胃酸中毒（RA）的严重程度前和产后的变异性，并确定这种变异性是否与其瘤胃细菌群落组成（BCC）的差异。根据瘤胃发酵变量，对个体奶牛RA严重程度的变异性进行了表征。还检查了黄芪饮食治疗对RA严重程度的影响。14个荷斯坦小母牛配对的预期产犊日期和BCS被分配到1的2个日粮处理：低浓度或高浓度的饮食。所有奶牛在产后接受相同的泌乳期饮食。从总共收集的瘤胃（d-50，-31和-14; 27个样品）和产后（d +14和+52; 31个样品）的58个瘤胃瘤胃样品中提取微生物DNA并通过PCR扩增，进行自动核糖体基因间间隔区分析。使用主成分分析法分析瘤胃变量随时间的变化[pH、挥发性脂肪酸（VFA）和酸中毒指标，包括在第54、-35、-14、-3、+3、+17、+37和+58天测量的低于5.8、5.5和5.2的瘤胃pH曲线下面积和持续时间]。根据每头奶牛的泌乳期和产后期之间的变化（定义为平均负荷的距离），将14头奶牛分为3组：最少酸中毒（n = 5）、最多酸中毒（n = 5）和中等酸中毒（n = 4）。酸中毒最严重组的奶牛产后RA严重程度（测量为总RA、轻度RA、中度RA和急性RA的持续时间;总RA、轻度RA和中度RA的pH曲线下面积）大于酸中毒组，并且两个时期之间的差异大于酸中毒最少的奶牛。类似地，RA指数（pH值的总面积）
The purpose of this study was to investigate variability among individual cows in their severity of ruminal acidosis (RA) pre- and postpartum, and determine whether this variability was related to differences in their ruminal bacterial community composition (BCC). Variability in the severity of RA among individual cows was characterized based on ruminal fermentation variables. Effects of prepartum dietary treatment on the severity of RA were also examined. Fourteen Holstein heifers paired by expected calving date and BCS were allotted to 1 of 2 prepartum dietary treatments: low-concentrate or high-concentrate diets. All cows received the same lactation diet postpartum. Microbial DNA extracted from 58 ruminal digesta samples in total collected prepartum (d -50, -31, and -14; 27 samples) and postpartum (d +14 and +52; 31 samples) and amplified by PCR, were subjected to automated ribosomal intergenic spacer analysis. Changes in ruminal variables over time [pH, volatile fatty acids (VFA), and acidosis indicators, including duration and area under the rumen pH curve below 5.8, 5.5, and 5.2, measured on d 54, -35, -14, -3, +3, +17, +37, and +58] were analyzed using principal components analysis. Based on the shift (defined as the distance of the mean loadings) between the prepartum and postpartum period for each cow, the 14 cows were classified into 3 groups: least acidotic (n = 5), most acidotic (n = 5), and intermediate (n = 4). Cows in the most acidotic group had greater severity of RA (measured as duration of total RA, mild RA, moderate RA, and acute RA; area under the pH curve for total RA, mild RA, and moderate RA) postpartum than prepartum, and this difference between periods was greater than for the least acidotic cows. Similarly, the RA index (total area of pH