The successful ensiling of lucerne (Medicago sativa L.) depends on a rapid acidification in the silo and consequently relies on a sufficient proliferation of, particularly homofermentative, lactic acid bacteria. Similarly, growth of spoilage bacteria, such as enterobacteria and clostridia, must be suppressed and silage additives are therefore frequently applied to promote favourable conditions during ensiling. Three silage additives or soil were applied during lucerne ensiling and investigated for their effects on silage quality characteristics and abundances of total bacteria as well as the bacterial key players Lactobacillus spp., homofermentative Lact. plantarum, heterofermentative Lact. buchneri, Clostridium spp. and Enterobacteriaceae after 30 days of storage. Inoculation with viable Lact. plantarum resulted in highest concentration of this species and excellent silage quality, i.e. high lactic acid concentration coupled with low acetic acid and ammonia-nitrogen concentrations. A sodium nitrite and hexamine-based additive did not support growth of lactic acid bacteria, which was also apparent by higher pH and low lactic acid concentration. No effect of treatments was found on spoilage-related enterobacteria and clostridia, even not when adding soil to lucerne to increase initial clostridial contamination. However, soil treatment resulted in increased ammonia-nitrogen and acetic acid concentrations. Consequently, among the bacterial key players, lactic acid bacteria concentrations were related to silage quality. Regarding spoilage bacteria, however, alterations in silage quality characteristics were not reflected in the abundances of enterobacteria and clostridia. Future investigations should underpin the present findings and help to understand how silage additives affect microbial key players and silage fermentation.

中文翻译：

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不同的青贮条件影响青贮饲料中主要细菌的发酵质量和丰度

卢塞恩青贮成功（紫花苜蓿L.) 依赖于筒仓中的快速酸化，因此依赖于乳酸菌的充分增殖，特别是同型发酵乳酸菌。同样，必须抑制腐败菌（如肠杆菌和梭状芽孢杆菌）的生长，因此经常使用青贮饲料添加剂来促进青贮期间的有利条件。在苜蓿青贮期间应用了三种青贮饲料添加剂或土壤，并研究了它们对青贮饲料质量特征和总细菌丰度以及细菌关键参与者的影响乳酸杆菌spp.，同型发酵的乳酸.植物, 异型发酵乳酸.布赫内里,梭菌属spp. 和肠杆菌科储存 30 天后。接种活菌乳酸.植物导致该物种的最高浓度和出色的青贮质量，即高乳酸浓度加上低乙酸和氨氮浓度。亚硝酸钠和六胺基添加剂不支持乳酸菌的生长，这在较高的 pH 值和较低的乳酸浓度下也很明显。没有发现处理对腐败相关的肠杆菌和梭状芽孢杆菌有影响，即使在苜蓿中添加土壤以增加初始梭状芽孢杆菌污染时也没有发现。然而，土壤处理导致氨氮和乙酸浓度增加。因此，在细菌的主要参与者中，乳酸菌浓度与青贮饲料质量有关。然而，关于腐败菌，青贮饲料质量特征的变化并未反映在肠杆菌和梭状芽胞杆菌的丰度上。未来的调查应该支持目前的研究结果，并有助于了解青贮饲料添加剂如何影响微生物的关键参与者和青贮饲料发酵。