Hammer Tobin J, Fierer Noah, Hardwick Bess, Simojoki Asko, Slade Eleanor, Taponen Juhani, Viljanen Heidi, Roslin Tomas
Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO, USA
Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO, USA Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO, USA.
Proc Biol Sci. 2016 May 25;283(1831). doi: 10.1098/rspb.2016.0150.
Antibiotics are routinely used to improve livestock health and growth. However, this practice may have unintended environmental impacts mediated by interactions among the wide range of micro- and macroorganisms found in agroecosystems. For example, antibiotics may alter microbial emissions of greenhouse gases by affecting livestock gut microbiota. Furthermore, antibiotics may affect the microbiota of non-target animals that rely on dung, such as dung beetles, and the ecosystem services they provide. To examine these interactions, we treated cattle with a commonly used broad-spectrum antibiotic and assessed downstream effects on microbiota in dung and dung beetles, greenhouse gas fluxes from dung, and beetle size, survival and reproduction. We found that antibiotic treatment restructured microbiota in dung beetles, which harboured a microbial community distinct from those in the dung they were consuming. The antibiotic effect on beetle microbiota was not associated with smaller size or lower numbers. Unexpectedly, antibiotic treatment raised methane fluxes from dung, possibly by altering the interactions between methanogenic archaea and bacteria in rumen and dung environments. Our findings that antibiotics restructure dung beetle microbiota and modify greenhouse gas emissions from dung indicate that antibiotic treatment may have unintended, cascading ecological effects that extend beyond the target animal.
抗生素通常用于促进牲畜健康和生长。然而，这种做法可能会通过农业生态系统中广泛存在的微生物和宏观生物之间的相互作用产生意想不到的环境影响。例如，抗生素可能通过影响牲畜肠道微生物群来改变温室气体的微生物排放。此外，抗生素可能会影响依赖粪便的非目标动物（如蜣螂）的微生物群及其提供的生态系统服务。为了研究这些相互作用，我们用一种常用的广谱抗生素对牛进行治疗，并评估其对粪便和蜣螂中微生物群的下游影响、粪便中温室气体通量以及蜣螂的大小、存活和繁殖情况。我们发现，抗生素处理改变了蜣螂体内的微生物群结构，蜣螂体内的微生物群落与它们所食用粪便中的微生物群落不同。抗生素对蜣螂微生物群的影响与蜣螂较小的体型或较少的数量无关。出乎意料的是，抗生素处理增加了粪便中的甲烷通量，这可能是通过改变瘤胃和粪便环境中产甲烷古菌与细菌之间的相互作用实现的。我们的研究结果表明，抗生素会改变蜣螂的微生物群结构并改变粪便中的温室气体排放，这表明抗生素处理可能会产生意想不到的、级联式的生态效应，且这种效应会超出目标动物的范围。
