贮藏时间对甜高粱青贮发酵品质、微生物群落组成和功能的影响  

Effects of storage time on the fermentation quality, bacterial community composition, and functional profile of sweet sorghum silage

作　　者：赵杰 尹雪敬 王思然 董志浩 李君风 贾玉山[2,3] 邵涛 ZHAO Jie;YIN Xue-jing;WANG Si-ran;DONG Zhi-hao;LI Jun-feng;JIA Yu-shan;SHAO Tao(College of Agro-grassland Science,Nanjing Agricultural University,Nanjing 210095,China;Key Laboratory of Forage Cultivation,Processing and High Efficient Utilization,Ministry of Agriculture,Inner Mongolia Agricultural University,Hohhot 010018,China;Key Laboratory of Grassland Resources,Ministry of Education,Inner Mongolia Agricultural University,Hohhot 010018,China)

机构地区：[1]南京农业大学草业学院,江苏南京210095 [2]内蒙古农业大学农业农村部饲草栽培加工与高效利用重点实验室,内蒙古呼和浩特010018 [3]内蒙古农业大学教育部草地资源重点实验室,内蒙古呼和浩特010018

出　　处：《草业学报》2023年第8期164-175,共12页Acta Prataculturae Sinica

基　　金：国家自然科学基金区域创新发展联合基金重点支持项目(U20A2003)资助

摘　　要：为评价贮藏时间对甜高粱青贮发酵品质、微生物群落组成和功能的影响,将蜡熟期甜高粱(SS)自然青贮1、3、7、15、30和60 d,开窖后,随机取样进行化学成分、发酵参数和微生物数量分析。同时,对鲜样、青贮7和60 d的甜高粱青贮饲料(SSS)进一步进行高通量测序和KEGG功能预测分析。结果表明,青贮60 d后,甜高粱青贮饲料呈低pH值、高乳酸含量和高乳乙比的同型乳酸发酵。肠杆菌属(26.0%)和泛菌属(25.7%)为SS鲜样的优势菌属,而明串珠菌属(34.1%)和乳球菌属(31.6%)则在7 d的SSS中占据优势,随后在60 d的SSS中被乳杆菌属(73.5%)取代。斯皮尔曼相关性热图显示乳杆菌属相对丰度与乳酸含量呈正相关,与pH值呈负相关。青贮前后微生物群落功能存在较大差异:青贮过程下调了氨基酸、能量、辅因子和维生素代谢,但上调了核苷酸和碳水化合物代谢。总体而言,高通量测序结合KEGG功能预测分析进一步证实了甜高粱青贮过程中球状乳酸菌至杆状乳酸菌的演替规律,并初步发现了碳水化合物代谢上调及氨基酸代谢下调的功能转变趋势。研究青贮过程中的微生物群落动态和功能变化对深入揭示厌氧发酵机理和生产高品质青贮饲料具有重要意义。In this study,we aimed to evaluate the chemical composition,fermentation quality,microbial community,and functional shifts of sweet sorghum(SS)during ensiling.SS harvested at the hard dough stage was naturally ensiled for 1,3,7,15,30,and 60 days.After opening the silo,SS silage(SSS)was randomly sampled for analyses of chemical composition,fermentation parameters,and microbial abundance.Fresh,7-day,and 60-day SSS were further subjected to high-throughput sequencing and Kyoto Encyclopedia of Genes and Genomes(KEGG)functional prediction analyses.After 60 days of ensiling,SSS displayed homolactic fermentation as characterized by a lack of butyric acid,a low pH value,a high lactic acid concentration,and a high ratio of lactic to acetic acid.Enterobacter(26.0%)and Pantoea(25.7%)were the most common genera in fresh SS,while Leuconostoc(34.1%)and Lactococcus(31.6%)were dominant in 7-day SSS and were subsequently replaced by Lactobacillus(73.5%)in 60-day SSS.A heatmap constructed using Spearman’s correlation coefficient values showed that Lactobacillus was positively related to the lactic acid concentration and negatively related to the pH value.The KEGG metabolic profiles differed substantially between before and after ensiling.The ensiling process downregulated the metabolism of amino acids,energy,cofactors and vitamins,but upregulated the metabolism of nucleotides and carbohydrates.Overall,high-throughput sequencing combined with KEGG functional prediction analyses further confirmed the succession of cocci-shaped lactic acid bacteria to rod-shaped lactic acid bacteria during the SS ensilage process,and revealed trends of up-regulated carbohydrate metabolism and down-regulated amino acid metabolism.A thorough knowledge of the changes in bacterial community dynamics and functional shifts of SS during ensiling is important for understanding the fermentation mechanism and may contribute to the production of high-quality SSS.

关 键 词：甜高粱 发酵品质 微生物群落演替 功能变化 青贮饲料 

分 类 号：S816.53[农业科学—饲料科学]