School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Qld, Australia.
School of Life Sciences, University of Lincoln, Lincoln, UK.
J Appl Microbiol. 2018 Mar;124(3):855-866. doi: 10.1111/jam.13688. Epub 2018 Feb 6.
The probiotic Bacillus amyloliquefaciens H57 increased weight gain, increased nitrogen retention and increased feed intake in ruminants when administered to the diet. This study aims to develop a better understanding of this probiotic effect by analysing changes in the rumen prokaryotic community.
Sequencing the 16S rRNA gene PCR amplicons of the rumen microbiome, revealed that ewes fed H57 had a significantly different rumen microbial community structure to Control sheep. In contrast, dairy calves showed no significant differences in rumen community structure between treatment groups. In both instances, H57 was below detection in the rumen community profile and was only present at low relative abundance as determined by qPCR.
The altered rumen microbial community in sheep likely contributes to increased weight gain through more efficient digestion of plant material. As no change occurred in the rumen community of dairy calves it is suggested that increased weight gain may be due to changes in community function rather than structure. The low relative abundance of H57 as determined by qPCR, suggests that weight gain was not directly mediated by the probiotic, but rather by influencing animal behaviour (feed consumption) and/or altering the native rumen community structure or function.
This study provides a novel look at the rumen prokaryotic community in both sheep and dairy calves when fed H57. These findings improve our understanding for the potential rumen community involvement in H57-enabled weight gain. The study reveals that the probiotic B. amyloliquefaciens H57 is capable of benefiting ruminants without colonizing the rumen, suggesting an indirect mechanism of action.
当将芽孢杆菌 H57 添加到饲料中时，它可以增加反刍动物的体重增加、氮保留和采食量。本研究旨在通过分析瘤胃原核生物群落的变化，更好地了解这种益生菌的作用。
对瘤胃微生物组的 16S rRNA 基因 PCR 扩增子进行测序，结果表明，饲喂 H57 的母羊的瘤胃微生物群落结构与对照羊有显著差异。相比之下，奶牛犊牛在处理组之间的瘤胃群落结构没有显著差异。在这两种情况下，H57 在瘤胃群落图谱中均低于检测水平，并且仅通过 qPCR 确定为低相对丰度。
绵羊中改变的瘤胃微生物群落可能通过更有效地消化植物物质来促进体重增加。由于奶牛犊牛的瘤胃群落没有发生变化，因此体重增加可能是由于群落功能而不是结构的变化。通过 qPCR 确定的 H57 的相对低丰度表明，体重增加不是直接由益生菌介导的，而是通过影响动物行为（饲料消耗）和/或改变本地瘤胃群落结构或功能来实现的。
本研究为饲喂 H57 的绵羊和奶牛犊牛的瘤胃原核生物群落提供了新的视角。这些发现提高了我们对潜在的瘤胃群落参与 H57 促进体重增加的理解。该研究表明，益生菌 B. amyloliquefaciens H57 能够使反刍动物受益，而无需在瘤胃中定植，这表明存在间接作用机制。
