不同尿素添加剂量对蒸汽爆破玉米秸秆体外瘤胃发酵和功能微生物数量的影响  

Effects of Different Urea Addition Levels on in Vitro Rumen Fermentation and Functional Microbial Populations of Steam⁃Exploded Corn Stover

作　　者：孙美杰 徐诣轩 曹玉荣[1] 杜风光 申军士[1] 朱伟云[1] SUN Meijie;XU Yixuan;CAO Yurong;DU Fengguang;SHEN Junshi;ZHU Weiyun(Laboratory of Gastrointestinal Microbiology,Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health,National Center for International Research on Animal Gut Nutrition,Nanjing Agricultural University,Nanjing 210095,China;Eco Zhuoxin Energy-Saving Technology(Shanghai)Co.,Ltd.,Shanghai 201109,China)

机构地区：[1]南京农业大学,国家动物消化道营养国际联合研究中心,江苏省消化道营养与动物健康重点实验室,消化道微生物研究室,南京210095 [2]易高卓新节能技术(上海)有限公司,上海201109

出　　处：《动物营养学报》2021年第7期3959-3969,共11页CHINESE JOURNAL OF ANIMAL NUTRITION

基　　金：江苏省农业科技自主创新资金(CX(19)3023);江苏省"一带一路"技术合作项目(BZ2018055)。

摘　　要：本试验旨在通过瘤胃体外发酵法研究不同尿素添加剂量对蒸汽爆破玉米秸秆瘤胃发酵和功能微生物数量的影响。采用2×3双因素试验设计,即2种玉米秸秆底物(未处理玉米秸秆与蒸汽爆破玉米秸秆)和3个尿素添加剂量(0、20、100 mg/dL),体外发酵72 h后测定总产气量、瘤胃发酵参数和功能微生物数量。结果显示:1)蒸汽爆破处理使玉米秸秆中中性洗涤纤维(NDF)和半纤维素含量降低,中性洗涤可溶物(NDS)和酸性洗涤纤维(ADF)含量增加。2)与未处理玉米秸秆相比,蒸汽爆破玉米秸秆的总产气量显著升高(P<0.01);随着尿素添加剂量的增加,总产气量线性降低(P<0.01)。3)玉米秸秆类型和尿素添加剂量对干物质消失率(DMD)(P<0.01)和氨态氮(NH3⁃N)浓度(P=0.02)有显著的交互作用,蒸汽爆破玉米秸秆的DMD显著高于未处理玉米秸秆(P<0.05);相同尿素添加剂量下,蒸汽爆破玉米秸秆的NH3⁃N浓度显著低于未处理玉米秸秆(P<0.05)。4)与未处理玉米秸秆相比,蒸汽爆破玉米秸秆的总挥发性脂肪酸(VFA)和乙酸浓度显著升高(P<0.05);随着尿素添加剂量的增加,玉米秸秆的总VFA(P<0.05)和乙酸浓度(P=0.04)存在二次剂量效应。5)玉米秸秆类型与尿素添加剂量对于总菌(P<0.01)、甲烷菌(P=0.04)和原虫数量(P<0.01)存在显著交互作用。结果提示,蒸汽爆破处理改变玉米秸秆的化学组成,通过增加功能微生物的数量来改善瘤胃发酵;在本底氨浓度(10.82 mg/dL)的基础上,添加适量(20 mg/dL)尿素可提高玉米秸秆体外发酵的总VFA产量,而过量添加尿素则会抑制玉米秸秆体外瘤胃发酵,但蒸汽爆破处理可缓解高氨浓度对其产生的不利影响。The objective of this study was to evaluate the effects of different urea addition levels on in vitro rumen fermentation and functional microbial populations of steam-exploded corn stover. The experiment was designed with a 2×3 factorial arrangement:two corn stover substrates(untreated corn stover and steam-exploded corn stover),and three urea addition levels(0,20 and 100 mg/dL). Ruminal fermentation parameters and functional microbial populations were measured after 72 h of rumen fermentation in vitro. The results showed as follows:1)steam explosion decreased the contents of neutral detergent fiber(NDF)and hemicellulose of corn stover,while increased the contents of neutral detergent soluble(NDS)and acid detergent fiber(ADF). 2)Compared with untreated corn stover,the total gas production of steam-exploded corn stover was significantly increased(P<0.01). The total gas production linearly decreased with the increase of urea addition level(P<0.01). 3)Significant interactions between corn stover type and urea addition level were detected for dry matter digestibility(DMD)(P<0.01)and ammonia(NH3-N)concentration(P = 0.02),the DMD of steam-exploded corn stover was significantly higher than that of untreated corn stover(P<0.05). Under the same urea addition level,the NH3-N concentration of steam-exploded corn stover was significantly lower than that of untreated corn stover(P<0.05). 4)Compared with untreated corn stover,the total volatile fatty acids(VFA)and acetate concentrations of steam-exploded corn stover were significantly increased(P<0.05). With the increase of urea addition level,the concentration of total VFA(P<0.05)and acetate concentrations(P = 0.04)displayed a quadratic dose response. 5)There were significant interactions between corn stover type and urea addition level on the populations of total bacteria(P < 0. 01),methanogens(P = 0. 04)and protozoa(P <0.01). In conclusion,steam explosion treatment changes the chemical composition of corn stover,improves the rumen fermentation by increasing the populations

关 键 词：蒸汽爆破 尿素 玉米秸秆 体外发酵 功能微生物 

分 类 号：S816[农业科学—饲料科学]