摘要
Ionophores and supplemental fat are fed to lactating cows to improve feed efficiency. Their effect on rumen fermentation is similar, but less is known about their impact on rumen microbes. The objective of this study was to determine the effects of monensin (M), bacitracin (B), and soybean oil (O) on microbial populations. Mixed cultures of rumen microbes were incubated in 5 dual-flow continuous fermentors and fed 13.8 g of alfalfa hay pellets daily (DM basis) for 16 d. All fermentors were allowed to stabilize for 4 d. From d 5 to 10, two fermentors received O (5% of diet DM), one fermentor received M (22 mg/kg), and one received B (22 mg/kg). From d 11 to 16, the 2 fermentors receiving O also received either M (OM) or B (OB) and O was included in the fermentors receiving M (MO) and B (BO). One fermentor served as the control and received 100% alfalfa pellets throughout the experiment. Each run was replicated 3 times. Samples were taken at 2 h after the morning feeding on d 4, 10, and 16 and were analyzed for bacterial populations using terminal restriction fragment length polymorphism. Volatile fatty acid concentration, methane production, and pH in the control cultures were not affected by time and remained similar during the entire experiment. The M and O treatments reduced molar concentration of acetate, increased concentration of propionate, and decreased methane production. Bacitracin did not alter acetate or propionate concentration, but reduced methane production. All 3 treatments (M, B, and O) altered the fragment patterns of microbial profiles. In contrast, treatments MO, OM, BO, and OB had little effect on culture fermentation despite differences in the patterns of microbial fragments. The terminal restriction fragment length polymorphism data suggest that microbial adaptation to the in vitro system in the control fermentor occurred within 4 d.
摘要译文
将离子载体和补充脂肪喂给泌乳牛以提高饲料效率。它们对瘤胃发酵的影响是相似的，但对其对瘤胃微生物的影响知之甚少。本研究的目的是确定莫能菌素（M），杆菌肽（B）和大豆油（O）对微生物种群的影响。将瘤胃微生物的混合培养物在5个双流连续发酵罐中孵育，并且每天（以干基计）供给13.8g苜蓿干草球粒，持续16天。所有发酵罐允许稳定4天。从第5天到第10天，两个发酵罐收到O（5％饮食DM），一个发酵罐收到M（22 mg / kg），另一个收到B（22 mg / kg）。从第11天到第16天，接收O的2个发酵罐也收到M（OM）或B（OB），O包含在接收M（MO）和B（BO）的发酵罐中。一个发酵罐作为对照并在整个实验中接受100％苜蓿颗粒。每次运行重复3次。在第4天，10天，并使用末端限制性片段长度多态性分析细菌群体。挥发性脂肪酸浓度，甲烷产量，并且对照培养物中的pH不受时间影响并且在整个实验期间保持相似。 M和O处理降低了乙酸的摩尔浓度，丙酸盐浓度增加，甲烷产量减少。杆菌肽不改变乙酸盐或丙酸盐浓度，但减少了甲烷产量。所有3种处理（M，B，和O）改变了微生物谱的碎片模式。相反，治疗MO，OM，BO，尽管微生物片段的模式不同，但OB对培养发酵影响不大。末端限制性片段长度多态性数据表明，对照发酵罐中的体外系统的微生物适应发生在4天内。
M.C.Johnson[*];A.A.Devine[†];J.C.Ellis[‡];A.M.Grunden[†];V.Fellner[*];. Effects of antibiotics and oil on microbial profiles and fermentation in mixed cultures of ruminal microorganisms[J]. Journal of Dairy Science, 2009,92(9): 4467-4480