不同饲喂方式对内蒙古白绒山羊瘤胃甲烷减排影响及其作用机理研究

Within the global range, the emission of agricultural source occupies 50% of the total methane emission caused by human activities. As reported in the Climate Change Secondary National Information Notification of PRC, in 2005, the total greenhouse gas emission in China was about 7.467 billion tons of carbon dioxide equivalence, of which, the occupation of carbon dioxide and methane gas was respectively 80.03% and 12.49%.In 2005, China totally discharged 44.45 million tons of methane, of which, the agricultural source occupied 56.62%, while the emission of animal intestine and excrement methane respectively occupied 57.13% and 11.36% of the agricultural source. Inner Mongolia white cashmere goats are famous variety of cashmere goats in our country, and the quantity of goats occupies 13% of the total inventory nationwide. However, alfalfa has a wide development prospect. Under the condition of ascertaining the natural grazing and supplementary feeding (grazing plus concentrate supplement as well as daily ration are merely green alfalfa hay as well as green alfalfa hay plus concentrate supplement) and other 4 conditions, ascertain the interaction mechanism and change rules of methane bacteria and the relevant microorganism in the generation process of rumen methane for Inner Mongolia white cashmere goats, and meanwhile, verify the relevant key flora generated by the methane and conduct analysis on the hydrogen concentration of rumen. Further comprehensively reveal the influence of microbial activities on the generation rules of methane and the emission flux mechanism, and provide theoretical and technical support for correctly evaluating the emission of methane from animals and the emission reduction.

全球范围内，农业源排放甲烷占由于人类活动造成的甲烷排放总量的50％。根据《中华人民共和国气候变化第二次国家信息通报》报道，2005年中国温室气体排放总量约为74.67亿吨二氧化碳当量，其中二氧化碳、甲烷气体所占的比重分别为 80.03%、12.49%。2005年，中国共排放甲烷4445万t，其中农业源占56.62%，而动物肠道和粪便甲烷排放分别占农业源的57.13%和11.36%。内蒙古白绒山羊是我国著名的绒山羊品种，山羊数量占全国总存栏数的13%。而苜蓿草具有广阔的发展前景。探明天然放牧及补饲（放牧加补饲精料、日粮仅为苜蓿青干草和苜蓿青干草加补饲精料）等4种条件下，探明内蒙古白绒山羊瘤胃甲烷生成过程中甲烷菌及相关微生物相互作用机制和变化规律，鉴定甲烷生成有关的关键菌群和瘤胃氢气浓度变化分析。进一步全方位揭示微生物活动影响甲烷生成规律和排放通量的机制，为今后准确评估动物甲烷排放量和减排提供

对甲烷菌及其相关微生物的研究成为当前减少畜禽甲烷排放的重要途径。内蒙古白绒山羊是我国著名的绒山羊品种，苜蓿草具有广阔的发展前景。为了探明不同日粮类型条件下绒山羊瘤胃甲烷在其合成过程中相关微生物的作用机制，发挥甲烷减排策略意义，本项目选择苜蓿青干草、苜蓿青干草加精料、玉米秸秆、玉米秸秆加精料为试验日粮，研究了在生产条件下不同类型的日粮对绒山羊CH4、氢气排放和瘤胃发酵特性的影响，并进行了瘤胃微生物多样性分析。研究结果表明，不同类型日粮对绒山羊瘤胃液的pH值、BCP浓度、丁酸浓度和乙酸/丙酸的影响差异不显著（P>0.05）；苜蓿补饲精料组瘤胃液NH3-N浓度（11.90mg/100ml）极显著高于其他组；苜蓿组、苜蓿补饲精料组的丙酸、戊酸、异戊酸、乙酸、TVFA浓度极显著大于玉米秸秆组、玉米秸秆补饲精料组（P<0.05）。 . 苜蓿补饲精料组CH4产量（12.63L/d）低于苜蓿组（14.97L/d）（P>0.05）；玉米秸秆补饲精料组的CH4产量（18.22L/d）显著低于玉米秸秆组（21.11L/d）（P<0.05）；苜蓿组的CH4产量极显著低于玉米秸秆组（P<0.01）；饲喂苜蓿所产生的甲烷菌数量比玉米秸秆组低，补饲精料后会进一步降低甲烷菌的数量。. 补饲精料后，绒山羊瘤胃产甲烷菌、细菌的多样性及丰富度均有所增高。苜蓿组产甲烷菌、细菌多样性及丰度均高于玉米秸秆组；苜蓿组产甲烷菌的优势菌门为广生古菌门，占比为54.55%；其他3组的优势菌门为未标记的细菌，占比分别为50.08%、62.53%、75.75%。各组的瘤胃细菌优势菌门均为拟杆菌门，苜蓿组、苜蓿补饲精料组、玉米秸秆组、玉米秸秆补饲精料组分别为75.84%、74.92%、80.69%、72.63%，其次为厚壁菌门。各组的瘤胃真菌优势菌门为子囊菌门。补饲精料有提高氢气浓度的趋势，各组间差异不显著（P>0.05）。