Dynamics of the bacterial communities and predicted functional profiles in wilted alfalfa silage

作者：Siran Wang, Junfeng Li, Jie Zhao, Zhihao Dong, Dong Dong, Tao Shao · 发表于：Journal of Applied Microbiology · 年份：2021 · DOI：10.1111/jam.15417 · 被引用次数：26 · 研究领域：Ruminant Nutrition and Digestive Physiology、Milk Quality and Mastitis in Dairy Cows、Probiotics and Fermented Foods

Abstract Aims To investigate the fermentation characteristics, bacterial community and predicted functional profiles during the ensiling of wilted alfalfa (Medicago sativa L.). Methods and Results First-cutting alfalfa was harvested at the early bloom stage, wilted for 6 h, and ensiled in laboratory-scale silos (1 L capacity). Triplicate silos were sampled after 1, 3, 7, 15, 30 and 60 days of ensiling, respectively. The bacterial communities of wilted alfalfa and silages on day 3 and 60 were assessed through high throughput sequencing technology, and their functional characteristics were evaluated according to the Kyoto Encyclopedia of Genes and Genomes using Tax4Fun. After 60 days of ensiling, alfalfa silage showed a moderate fermentation quality, indicated by high lactic acid (56.7 g kg−1 dry matter [DM]) and acetic acid (39.4 g kg−1 DM) contents, and low concentrations of butyric acid (2.12 g kg−1 DM) and ammonia nitrogen (128 g kg−1 total nitrogen). Lactobacillus rapidly became predominant on day 3 and increased to 60.4% on day 60. Results of functional prediction analyses showed that the metabolism of amino acid, energy, cofactors and vitamins were reduced, while metabolism of nucleotide and carbohydrate were increased during ensiling. Fructokinase, 1-phosphofructokinase and pyruvate kinase played important roles in producing lactic acid. The production of acetic acid may be correlated with the enhancement of 6-phosphogluconate dehydrogenase and acetyl-CoA synthetase. Co...