饲粮非纤维性碳水化合物/中性洗涤纤维水平对奶牛瘤胃体外发酵参数和微生物区系的影响  

Effects of Dietary Non-Fiber Carbohydrate/Neutral Detergent Fiber Levels on Rumen Fermentation Parameters and Microflora of Dairy Cows in Vitro

作　　者：张林 夏海斌 徐洁 曾涵芳 韩兆玉 ZHANG Lin;XIA Haibin;XU Jie;ZENG Hanfang;HAN Zhaoyu(Institute of Dairy Science,College of Animal Science and Technology,Nanjing Agricultural University,Nanjing 210095,China;Beijing Challenge Bio-Technology Co.,Ltd.,Beijing 100081,China)

机构地区：[1]南京农业大学动物科技学院乳牛科学研究所,南京210095 [2]北京挑战生物技术有限公司,北京100081

出　　处：《动物营养学报》2022年第9期5824-5839,共16页CHINESE JOURNAL OF ANIMAL NUTRITION

基　　金：江苏现代农业(奶牛)产业技术体系项目(JATS[2021]468)。

摘　　要：本试验旨在研究饲粮不同非纤维性碳水化合物/中性洗涤纤维(NFC/NDF)水平对奶牛瘤胃体外发酵参数和微生物区系动态变化的影响。获取3头健康中国荷斯坦奶牛[体重(605±35)kg]的瘤胃液,按1∶2比例与缓冲液混合用作发酵液。根据饲粮NFC/NDF水平[1.38(A)、1.19(B)、1.08(C)]将发酵底物分为3组,体外发酵48 h。在2、4、6、12、18、24、36和48 h时测定产气量(GP);在第6、12、24和48 h时,每组取出4个发酵瓶采集发酵液,测定pH后将样品分装冻存在-20℃冰箱,用于测定挥发性脂肪酸(VFA)、乳酸、氨态氮(NH 3-N)和微生物蛋白(MCP)含量,用于瘤胃细菌16S rRNA基因测序分析的样品置于液氮中保存。结果表明:1)饲粮NFC/NDF水平、发酵时间及二者交互作用对GP、pH、MCP、NH 3-N、丙酸含量和乙酸/丙酸值均有显著影响(P<0.05);饲粮NFC/NDF水平及其与发酵时间的交互作用对总挥发性脂肪酸(TVFA)和乙酸含量有显著影响(P<0.05)。发酵时间对乳酸和丁酸含量有显著影响(P<0.01)。2)高通量测序分析表明,在门水平和属水平,主要细菌(平均相对丰度大于1%)的相对丰度随发酵时间显著变化(P<0.05)。在门水平上,核心菌群的地位不变;在属水平,部分细菌的优势地位发生改变。其中未分类的RF16和未分类的克里斯滕森菌科相对丰度在12 h后降到1%以下;而Oribacterium和巨球形菌属相对丰度从低于1%逐渐增加到10%以上。3)Pearson相关性分析显示,解琥珀酸菌属与GP、TVFA、乙酸、丙酸和丁酸呈显著负相关(r<-0.9,P<0.05),Oribacterium与GP和MCP呈显著正相关(r>0.9,P<0.05)。由此可知,在瘤胃体外发酵过程中,饲粮NFC/NDF水平与瘤胃微生物区系间存在交互作用,发酵参数和微生物区系经历了动态变化;此外,发酵产物与部分细菌之间存在显著的相关性。This experiment was conducted to investigate the effects of different dietary non-fiber carbohydrate/neutral detergent fiber(NFC/NDF)levels on dynamic changes of rumen fermentation parameters and microflora of dairy cows in vitro.Rumen fluid from three healthy Chinese Holstein dairy cows with body weight of(605±35)kg was mixed with buffer at a ratio of 1∶2 as fermentation broth.The substrates were divided into three groups according to the dietary NFC/NDF levels[1.38(A),1.19(B)and 1.08(C)]and fermented in vitro for 48 h.Gas production(GP)was measured at 2,4,6,12,18,24,36 and 48 h of in vitro fermentation.At the 6,12,24 and 48 h,4 fermentation bottles were taken out from each group to collect the fermentation liquid and determine the pH.The samples were frozen at-20℃for the determination of volatile fatty acid(VFA),lactic acid,ammonia nitrogen(NH 3-N)and microbial protein(MCP),respectively.Samples for rumen bacterial 16S rRNA gene sequencing analysis were stored in liquid nitrogen.The results showed as follows:1)dietary NFC/NDF level,fermentation time and their interaction had significant effects on GP,pH,contents of MCP,NH 3-N,propionate acid and acetate/propionate ratio(P<0.05).Dietary NFC/NDF level and its interaction with fermentation time had significant effects on the contents of total volatile fatty acid(TVFA)and acetate(P<0.05).The fermentation time had a significant effect on the content of lactate and butyrate(P<0.05).2)High-throughput sequencing analysis showed that the relative abundance of major bacteria(average relative abundance>1%)varied significantly with fermentation time at phylum and genus level(P<0.05).The status of core bacteria at phylum level remained unchanged,while the dominance of some bacteria at genus level changed.At genus level,the relative abundance of unclassified RF16 and unclassified Christensenellaceae gradually decreased to less than 1%after 12 h,while the relative abundance of Oribacterium and Macrobacterium gradually increased from less than 1%to more than 10%.3)The Pear

关 键 词：奶牛 NFC/NDF 体外发酵 瘤胃微生物区系 

分 类 号：S816[农业科学—饲料科学]