Conservation and Production Research Laboratory, USDA ARS, Bushland, TX 79012, USA.
BMC Microbiol. 2012 Feb 24;12:25. doi: 10.1186/1471-2180-12-25.
The high demand for ethanol in the U.S. has generated large stocks of wet distillers grains (DG), a byproduct from the manufacture of ethanol from corn and sorghum grains. Little is known, however, about the potential influence of dietary DG on fecal microbial community structure. A better understanding of the microbial population in beef cattle feces could be an important monitoring tool to facilitate goals of improving nutrient management, increasing animal growth performance and decreasing odors and/or shedding of pathogens. Five diets consisting of a traditional diet fed to finishing beef cattle in the Southern High Plains of Texas-CON (steam-flaked corn control with 0% DG), and four concentrations of DG in the dietary dry matter; 10 C (10% corn-based DG), 5S (5% sorghum-based DG), 10S (10% sorghum DG), and 15S (15% sorghum DG) were fed to steers at the Texas Tech University Burnett Animal Center. Diets were essentially isonitrogenous with a formulated crude protein value of 13.5%.
Fecal grab samples were obtained from 20 steers (n = 4 per diet) and the barcoded DNA pyrosequencing method was used to generate 127,530 16S operational taxonomic units (OTUs). A total of 24 phyla were observed, distributed amongst all beef cattle on all diets, revealing considerable animal to animal variation, however only six phyla (core set) were observed in all animals regardless of dietary treatment. The average abundance and range of abundance, respectively of the core phyla were as follows: Firmicutes (61%, 19 to 83%), Bacteroidetes (28%, 11 to 63%), Proteobacteria (3%, 0.34 to 17.5%), Tenericutes (0.15%, 0.0 to 0.35%), Nitrospirae (0.11%, 0.03 to 0.22%), and Fusobacteria (0.086%, 0.017 to 0.38%). Feeding DG-based diets resulted in significant shifts in the fecal microbial community structure compared with the traditional CON. Four low abundance phyla significantly responded to dietary treatments: Synergistetes (p = 0.01), WS3 (p = 0.054), Actinobacteria (p = 0.06), and Spirochaetes (p = 0.06).
This is, to our knowledge, the first study using this method to survey the fecal microbiome of beef cattle fed various concentrations of wet DG. Comparison of our results with other cattle DNA sequencing studies of beef and dairy cattle feces from a variety of geographical locations and different management practices identifies a core set of three phyla shared across all cattle. These three phyla, in order of relative abundance are; Firmicutes, Bacteroidetes, and Proteobacteria. The presence of large animal-to-animal variation in cattle microbiome was noted in our study as well as by others.
美国对乙醇的高需求产生了大量的湿酒糟（DG），这是一种从玉米和高粱谷物中制造乙醇的副产品。然而，人们对日粮 DG 对粪便微生物群落结构的潜在影响知之甚少。更好地了解肉牛粪便中的微生物种群可能是一种重要的监测工具，有助于实现改善养分管理、提高动物生长性能以及减少气味和/或病原体排放的目标。五种日粮由在德克萨斯州南部高地饲养育肥牛的传统日粮组成-CON（蒸汽压片玉米对照，DG 含量为 0%），以及日粮干物质中四种 DG 浓度；10C（10%基于玉米的 DG）、5S（5%基于高粱的 DG）、10S（10%基于高粱的 DG）和 15S（15%基于高粱的 DG）。日粮基本等氮，配方粗蛋白值为 13.5%。
从 20 头阉牛（n = 4 头/日粮）中采集粪便抓取样本，并使用带有条形码的 DNA 焦磷酸测序方法生成 127530 个 16S 操作分类单位（OTU）。共观察到 24 个门，分布在所有日粮的所有肉牛中，显示出相当大的动物间变异，但仅观察到 6 个门（核心集）存在于所有动物中，无论日粮处理如何。核心门的平均丰度和丰度范围分别如下：厚壁菌门（61%，19-83%）、拟杆菌门（28%，11-63%）、变形菌门（3%，0.34-17.5%）、柔膜菌门（0.15%，0.0-0.35%）、硝化螺旋菌门（0.11%，0.03-0.22%）和梭杆菌门（0.086%，0.017-0.38%）。与传统的 CON 相比，基于 DG 的日粮喂养导致粪便微生物群落结构发生显著变化。四个低丰度门对日粮处理有显著反应：互养菌门（p = 0.01）、WS3（p = 0.054）、放线菌门（p = 0.06）和螺旋体门（p = 0.06）。
据我们所知，这是首次使用该方法调查不同浓度湿 DG 喂养肉牛粪便微生物组的研究。将我们的结果与来自不同地理位置和不同管理实践的其他牛 DNA 测序研究进行比较，确定了所有牛共有的三个核心门。这三个门按相对丰度顺序排列是：厚壁菌门、拟杆菌门和变形菌门。我们的研究以及其他研究都注意到牛微生物组中存在大量的动物间变异。
