Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom.
PLoS One. 2013 Jul 2;8(7):e67824. doi: 10.1371/journal.pone.0067824. Print 2013.
It has been suggested that the ability of live yeast to improve milk yield and weight gain in cattle is because the yeast stimulates bacterial activity within the rumen. However it remains unclear if this is a general stimulation of all species or a specific stimulation of certain species. Here we characterised the change in the bacterial population within the rumen of cattle fed supplemental live yeast. Three cannulated lactating cows received a daily ration (24 kg/d) of corn silage (61% of DM), concentrates (30% of DM), dehydrated alfalfa (9% of DM) and a minerals and vitamins mix (1% of DM). The effect of yeast (BIOSAF SC 47, Lesaffre Feed Additives, France; 0.5 or 5 g/d) was compared to a control (no additive) in a 3 × 3 Latin square design. The variation in the rumen bacterial community between treatments was assessed using Serial Analysis of V1 Ribosomal Sequence Tag (SARST-V1) and 454 pyrosequencing based on analysis of the 16S rRNA gene. Compared to the control diet supplementation of probiotic yeast maintained a healthy fermentation in the rumen of lactating cattle (higher VFA concentration [high yeast dose only], higher rumen pH, and lower Eh and lactate). These improvements were accompanied with a shift in the main fibrolytic group (Fibrobacter and Ruminococcus) and lactate utilising bacteria (Megasphaera and Selenomonas). In addition we have shown that the analysis of short V1 region of 16s rRNA gene (50-60 bp) could give as much phylogenetic information as a longer read (454 pyrosequencing of 250 bp). This study also highlights the difficulty of drawing conclusions on composition and diversity of complex microbiota because of the variation caused by the use of different methods (sequencing technology and/or analysis).
有人认为，活酵母提高奶牛产奶量和体重增加的能力是因为酵母刺激了瘤胃内细菌的活性。然而，目前尚不清楚这是对所有物种的普遍刺激，还是对某些物种的特定刺激。在这里，我们描述了补充活酵母后奶牛瘤胃内细菌种群的变化。三头泌乳奶牛接受了每日日粮（24 公斤/天）的玉米青贮（干物质的 61%）、浓缩物（干物质的 30%）、脱水紫花苜蓿（干物质的 9%）和矿物质和维生素混合物（干物质的 1%）。酵母（BIOSAF SC 47，Lesaffre Feed Additives，法国；0.5 或 5 克/天）的效果与对照（无添加剂）在 3×3 拉丁方设计中进行了比较。采用基于 16S rRNA 基因分析的序列分析 V1 核糖体序列标签（SARST-V1）和 454 焦磷酸测序，评估了处理之间瘤胃细菌群落的变化。与对照饮食相比，益生菌酵母的补充维持了泌乳奶牛瘤胃的健康发酵（更高的 VFA 浓度[仅高酵母剂量]、更高的瘤胃 pH 值以及更低的 Eh 和乳酸盐）。这些改善伴随着主要纤维分解菌群（Fibrobacter 和 Ruminococcus）和利用乳酸盐的细菌（Megasphaera 和 Selenomonas）的转移。此外，我们还表明，短 16s rRNA 基因 V1 区（50-60bp）的分析可以提供与更长读长（250bp 的 454 焦磷酸测序）一样多的系统发育信息。这项研究还强调了由于使用不同方法（测序技术和/或分析）引起的变化，很难对复杂微生物群落的组成和多样性得出结论。
