The clostridial fermentation caused by the outgrowth of Clostridia was mainly responsible for the silage anaerobic deterioration. Our previous results showed that Clostridium perfringens dominated the clostridial community in poor-fermented alfalfa silage. This study was conducted to further examine the role of C. perfringens in silage anaerobic deterioration through fermentation products and the microbial community analyses. Direct-cut alfalfa was ensiled with C. perfringens contamination (CKC) or with the addition of Lactobacillus plantarum, sucrose and C. perfringens (LSC). Contamination with C. perfringens enhanced the clostridial fermentation in CKC silage, as indicated by high contents of butyric acid, ammonia nitrogen and Clostridia, while LSC silage was well preserved. The genera Bifidobacterium, Garciella and Clostridium dominated the bacterial community in CKC silage, while predominate genus was replaced by Lactobacillus in LSC silage. The clostridial community in CKC silage was dominated by Garciella sp. (26.9 to 58.1%) and C. tyrobutyricum (24.4 to 48.6%), while the relative abundance of C. perfringens was below 5.0%. Therefore, the effect of Clostridia contamination on ensiling fermentation was dependent on the ensilability of the silage material. Garciella sp. and C. tyrobutyricum, rather than C. perfringens, played dominant role in the clostridial fermentation in CKC silage.

中文翻译：

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元基因组分析揭示了产气荚膜梭菌在苜蓿青贮饲料厌氧性退化中的作用。

梭状芽胞杆菌生长所引起的梭菌发酵主要是青贮饲料厌氧降解的原因。我们以前的研究结果表明，在发酵不良的苜蓿青贮饲料中，产气荚膜梭状芽胞杆菌在梭菌中占主导地位。通过发酵产物和微生物群落分析，进一步研究了产气荚膜梭菌在青贮饲料厌氧降解中的作用。直切苜蓿与产气荚膜梭菌污染（CKC）或加入植物乳杆菌，蔗糖和产气荚膜梭菌（LSC）青贮。如高浓度的丁酸，氨氮和梭状芽胞杆菌所示，产气荚膜梭菌的污染增强了CKC青贮饲料中的梭菌发酵，而LSC青贮饲料得到了很好的保存。双歧杆菌属 在CKC青贮饲料中，Garciella和Clostridium占据了细菌群落，而在LSC青贮饲料中，乳杆菌取代了主要属。CKC青贮中的梭菌群落主要由Garciella sp。（26.9至58.1％）和酪丁酸梭菌（24.4至48.6％），而产气荚膜梭菌的相对丰度低于5.0％。因此，梭菌污染对青贮发酵的影响取决于青贮材料的可青贮性。Garciella sp。酪氨酸丁酸梭菌而不是产气荚膜梭菌在CKC青贮饲料的梭菌发酵中起主导作用。产气荚膜炎低于5.0％。因此，梭菌污染对青贮发酵的影响取决于青贮材料的可青贮性。Garciella sp。酪氨酸丁酸梭菌而不是产气荚膜梭菌在CKC青贮饲料的梭菌发酵中起主导作用。产气荚膜炎低于5.0％。因此，梭菌污染对青贮发酵的影响取决于青贮材料的可青贮性。Garciella sp。酪氨酸丁酸梭菌而不是产气荚膜梭菌在CKC青贮饲料的梭菌发酵中起主导作用。