分子生物学技术在瘤胃微生态研究中的应用

综述了PCR测定,DGGE,以PCR为基础的rRNA/rDNA分析,分子标记等分子生物学技术在瘤胃微生物数量、群落结构、功能分析中的应用,并就其应用前景进行了探讨。分子生物学技术可以从基因和分子水平上为研究瘤胃微生态提供可靠而丰富的依据。认为有必要应用分子生物学技术,加强瘤胃微生物在功能和互作方面的研究。     

瘤胃原虫的作用及分子生物学技术在其研究中的应用

原虫是瘤胃微生态系统中重要的微生物群体之一,其种群构成及与其他瘤胃微生物之间的相互关系是当代瘤胃消化代谢研究的一个热点,而关于瘤胃原虫保留与否的争论更是由来已久,文章对此进行了翔实的论述,并简要综述了分子生物学技术在瘤胃原虫研究中的最新进展。     

实时荧光定量PCR技术在研究反刍动物消化道微生物菌群生态学上的运用

建立在以培养为基础的传统的估测瘤胃细菌的方法正在快速地被以核酸为基础的现代技术所取代。这些技术以SSUrDNA序列分析为基础，SSUrDNA序列分析提供了建立在系统发育树上的分类体系，用来记数和鉴定微生物菌群。最近包括PCR在内的许多分子生物学方法，提供了不依赖于培养的新技术，使人们对瘤胃微生物群落组成和丰度有了进一步了解。实时荧光定量PCR技术作为一种核酸定量的手段，以其高灵敏性、高特异性、高精确度、实时性、污染少等优点，在瘤胃微生物生态学中逐渐得到广泛的应用。文章就利用实时荧光定量PCR技术定量瘤胃纤维分解菌和产甲烷菌的发展过程进行了报道。     

大额牛瘤胃细菌16S rRNA基因序列分析

【目的】研究大额牛(Bos frontalis）瘤胃细菌16S rRNA基因序列,为揭示大额牛瘤胃细菌组成的多样性以及开发这一珍稀生物资源提供分子生物学依据。【方法】采用细菌通用引物F27和R1492对目标基因进行PCR扩增,克隆、测序后利用Neighbor-joining方法构建系统进化树。【结果】共获得147个16S rRNA基因序列,在GenBank登录号为DQ673466～DQ673612。按照97%的相似性标准,这些序列被分为86个操作分类单元。有16个序列与已培养菌的序列相似性≥97%,占总序列的10.9%;另有22个序列与已培养菌的序列相似性为90%～97%,占总序列的15%;剩余109个序列为未培养、鉴定菌,所占比例高达74.1%。系统进化分析显示,大额牛瘤胃细菌主要分布于低G+C含量细菌门（57.1%）和噬纤维菌/屈扰杆菌/拟杆菌门（42.2%）,仅有一个序列位于螺旋体门。【结论】本试验获得了大额牛瘤胃细菌16S rRNA基因序列,为进一步研究大额牛瘤胃微生态系统组成及其与饲料消化之间的关系奠定了基础。     

微生态制剂对奶牛产奶量和乳品质的影响

正微生态制剂可以调节瘤胃菌群活力及数量,增强瘤胃功能,提高饲料转化率,增加奶量并提升牛乳品质;调节肠道菌群平衡,减少肠道疾病,因此,从理论上来说微生态制剂可以从根本上增强奶牛生产性能[1]。本试验旨在研究微生态制剂对奶牛产奶量、乳品质和牛乳体细胞数的影响,为微生态制剂在生产应用中提供参考。1试验材料与方法1.1试验材料微生态制剂;健康高产奶牛。1.2试验日粮试验期间奶牛的饲喂方式及日常管理均按照牛场的常规管     

双峰驼瘤胃微生物总DNA的提取与纯化

[目的]提取高质量的双峰驼瘤胃微生物总DNA,为采用免培养技术研究双峰驼瘤胃微生物奠定基础.[方法]采集双峰驼瘤胃内容物,用酶解(溶菌酶、蛋白酶K)、冻融和表面活性剂十二烷基磺酸钠(sodium dodecyl sulfate,SDS)、溴化十六烷三甲基铵(Cetyltrimethyl Ammonium Bromide,CTAB)多种处理相结合,提取微生物总DNA,并用Omega Gel Extraction kit纯化.[结果]提取到的瘤胃微生物总DNA片段大于23 kb,纯化后的DNA可用于PCR,酶切及克隆等进一步的分子生物学研究.[结论]用该提取方法得到的总DNA能够满足分子生物学试验的要求.     

奶牛瘤胃酸中毒的微生态制剂疗法

瘤胃酸中毒是由于奶牛采食不当（精饲料过量）而引起前胃机能障碍的一种营养代谢性疾病，严重影响奶牛的生产性能甚至危及奶牛的生命健康。微生态制剂作为一种抗生素替代品，被广泛应用在奶牛瘤胃酸中毒治疗中且能够取得良好效果。从瘤胃酸中毒的原因、微生态制剂的作用以及在治疗奶牛瘤胃酸中毒中的应用几方面对瘤胃酸中毒的治疗方法进行综述，以期为广大同行提供参考。     

饲料及饲料添加剂对奶牛产奶性能的影响

综述了过瘤胃氨基酸、非蛋白氮、过瘤胃蛋白、微生态制剂、微量元素、大豆异黄酮、过瘤胃胆碱等7种饲料及饲料添加剂对提高奶牛产奶量的作用,旨在为奶牛生产提供参考。     

酵母菌种的筛选及其对反刍动物的影响

随着酵母类饲料添加剂在反刍动物中应用的日益增加,酵母菌对瘤胃作用的生物学机理及酵母菌与瘤胃内微生物的相互作用逐渐成为研究热点。文章针对目前国内外新型酵母菌种的筛选工作,在影响新型酵母菌筛选的因素,如何利用分子生物学技术选择新型酵母菌种、以及新型酵母对反刍动物的作用机理等方面进行了分析,为进一步研究提供理论依据。     

分子生物学技术在鞘翅目昆虫分类研究中的应用

随着生物技术的迅猛发展,分子生物学技术已越来越多地被应用在昆虫的分类学研究中.笔者概述了核酸序列分析、RFLP技术、RAPD技术、分子杂交技术、同工酶电泳技术、SSCP以及DSCP技术在鞘翅目昆虫分类研究中的应用情况,并展望了分子生物学技术在鞘翅目昆虫研究中的广阔前景.     

Initial detection of the quorum sensing autoinducer activity in the rumen of goats in vivo and in vitro

Quorum sensing(QS) is a type of microbe-microbe communication system that is widespread among the microbial world, particularly among microorganisms that are symbiotic with plants and animals. Thereby, the cell-cell signalling is likely to occur in an anaerobic rumen environment, which is a complex microbial ecosystem. In this study, using six ruminally fistulated Liuyang black goats as experimental animals, we aimed to detect the activity of quorum sensing autoinducers(AI) both in vivo and in vitro and to clone the lux S gene that encoded autoinducer-2(AI-2) synthase of microbial samples that were collected from the rumen of goats. Neutral detergent fiber(NDF) and soluble starch were the two types of substrates that were used for in vitro fermentation. The fermented fluid samples were collected at 0, 2, 4, 6, 8, 12, 24, 36, and 48 h of incubation. The acyl-homoserine lactones(AHLs) activity was determined using gas chromatography-mass spectrometer(GC-MS) analysis. However, none of the rumen fluid extracts that were collected from the goat rumen showed the same or similar fragmentation pattern to AHLs standards. Meanwhile, the AI-2 activity, assayed using a Vibrio harveyi BB170 bioassay, was negative in all samples that were collected from the goat rumen and from in vitro fermentation fluids. Our results indicated that the activities of AHLs and AI-2 were not detected in the ruminal contents from six goats and in ruminal fluids obtained from in vitro fermentation at different sampling time-points. However, the homologues of lux S in Prevotella ruminicola were cloned from in vivo and in vitro ruminal fluids. We concluded that AHLs and AI-2 could not be detected in in vivo and in vitro ruminal fluids of goats using the current detection techniques under current dietary conditions. However, the microbes that inhabited the goat rumen had the potential ability to secrete AI-2 signaling molecules and to communicate with each other via AI-2-mediated QS because of the presence of lux S.     

Postmodern management of starchy grains for ruminants: A barley grain perspective

Maintaining optimal rumen conditions faces many challenges when feeding ruminants barley grain (BG). This is because >90% of BG endosperm can be rapidly degraded to acids, peptides, and ammonia, whereas corn grain is degraded more slowly and only by 35–50%. Excessive processing may reduce and maintain rumen pH under 5.8, causing prolonged subacute rumen acidosis (SARA) and suppressed immunity. Steam-rolling and grinding are two main global processing methods for BG. It is criticized how inaccurately inherited focus on processing rather than accurate dietary inclusion rate of BG has compromised rumen and ruminant health. Overemphasis on processing methods and quality control have kept producers far from granting deserving thoughts into safe BG inclusion rates under different feeding programs. A major philosophy for steam processing of hard grains (e.g., corn and sorghum) is to increase rumen starch and protein fermentation extent, whereas in softer grains (e.g., BG) a primary goal is totally different, being instead to control and decelerate fermentation shortly post-feeding. These aims must be profoundly appreciated to maximize microbial mass yield and overall VFA production with minimized risks from SARA and immune dysfunction. Optimum dietary inclusion rates and physical form of BG in relation to physiological stage and lactation performance are discussed. In practice, challenges usually arise from too-complex outlooks. Main challenges faced by ruminant industries will not be to alleviate or attenuate disorders such as SARA and pro-inflammatory reactions, but instead to prevent and minimize their occurrence. A perturbing trend in modern ruminant industries has been creating health problems by improper feeding strategies and investing time and other resources to overcome such problems. Optimum processing techniques and feeding strategies of BG should aim to minimize metabolic complexities, and improve economics by more effective prognosis, diagnosis, and treatment. Effectual ruminant management is in controlled microbial cereal starch utilization in the rumen. Rumen is a foremost target to improve starch and BG assimilation in postmodern ruminants.     

畜禽常见内科病的诊断及处理技术探析

阐述了畜禽常见消化系统疾病的诊断及处理方法,包括急性胃肠炎、便秘、前胃弛缓、瘤胃臌胀、瘤胃积食及肠阻塞几种疾病,并从感冒及支气管肺炎方面介绍了常见呼吸系统疾病的诊断及处理方法。     

玛纳斯河流域绿洲林业生产的新变化——开发水土资源发展林业生产

随着社会经济发展、现代生产技术的广泛应用及新的土地承包、林业政策法规的贯彻,玛纳斯河流域(全疆)绿洲在20世纪60、70年代建立的农田防护林体系,需要在思想观念及生产技术等方面有相应的变化,建立新的防护林体系,适应新农村建设.开发新的水土资源,提高水土资源的利用效率,挖掘水土潜力发展现代林业生产;将生态效益与经济、社会效益结合,不同地区又有所侧重,是建立新防护林体系的共同特点,充分体现出现代绿洲林业及现代农业的共同要求.有利于促进农业现代化发展、新农村建设及荒漠化生态系统的恢复、重建.     

Barley forages for modern global ruminant agriculture: A review

Ruminants have evolved on forages that comprise major portions of most modern dairy and beef cattle diets. Cattle require minimum amount of effective fiber to maintain healthy rumen conditions. However, high fibre levels limits feed intake. Dietary fiber levels and physical properties contribute to such hypophagia. Forage bulkiness, particle size, lignification and rumen passage rate determine fiber quality. Barley forage (BF, Hordeum vulgare, L.) serves dairy diets where and when alfalfa or corn silages are less accessible. Being lower in protein, intermediate in soluble protein, and higher in starch and cellulose, barley silage (BS) is a suitable replacement for alfalfa silage. Barley forages have usually lower fiber levels among winter cereal crops. Barley forages may not reduce feed intake as much as other cereal crops, notably triticale and oats. Beef studies suggest superior or similar weight gain and feed efficiency by feeding BS versus wheat, triticale and oat silages. Growth response to BS appears comparable to corn silage. Reduced BS particle size reduces chewing activity in lactating cows, and even with adequate fiber intake has little effect on milk fat. Inoculants containing Lactobacillus buchneri, Lactobacillus plantarum, Pediococcus pentosaceus, and Propionibacterium freudenreichii along with carbohydrases can lower silage pH and improve organic acids production and silage aerobic stability. Altered barley silage chop length alters chewing activity but not necessarily rumen pH. Maturity stage affects nutritional value of BF due to altered protein and fiber contents and rumen fermentation patterns. Genetic variance among BF cultivars can affect nutrient profiles and rumen digestibility. Barley forages are cost-effective entities along with alfalfa hay and silage and corn silage for environmentalist ruminants to host optimal rumen and peripheral nutrient metabolism. Adequate effective fiber with sufficient but not very high fermentable starch, and modest degradable proteins make BF a unique ingredient for the sustainable modern ruminant production.     

徐淮白山羊瘤胃细菌和原虫的类群结构研究

 【目的】研究以稻草为主的日粮条件下徐淮白山羊瘤胃细菌和原虫的类群结构。【方法】以4只安装瘤胃瘘管的徐淮山羊为试验动物,PCR扩增瘤胃细菌16S rDNA序列,利用分子克隆与测序分析、细胞计数等技术,解析瘤胃细菌和原虫群体的类群组成。【结果】获得的细菌克隆基本归为两簇：与瘤胃球菌R.bromii YE282相似性为95%的XHGR1、与瘤胃R-7菌相似性为98%的XHGR3,XHGR2位于另立的R. flavefaciens簇。瘤胃球菌属细菌占细菌克隆总数的比例较高（33.33%）,原虫生物量略低于细菌,占瘤胃生物总量的44.83%。群体主要有内毛属、双毛亚科、前毛属、头毛属和等毛科等原虫,其中内毛属原虫比例最高为74.25%。【结论】以稻草为主的日粮条件下,徐淮白山羊瘤胃中细菌和原虫生物量相近,瘤胃球菌属细菌和内毛属原虫分别是瘤胃细菌和原虫区系的优势类群。     

黄淮白山羊瘤胃微生物Fosmid文库的构建与分析

采用CTAB法和蛋白酶K法提取黄淮白山羊瘤胃微生物总DNA,酶切获得DNA片段,大小为23～50 kb,以E.coli EPI300为宿主细胞,构建瘤胃微生物宏基因Fosmid文库。研究发现该文库共获得克隆28 800个,插入片段大小约35 kb,空载率小于2%,容量1 008 Mb。通过羧甲基纤维素酶和木聚糖酶(Xylanase)活性筛选,分别获得具有两种酶活性的阳性克隆60和32个,木聚糖酶和羧甲基纤维素酶(CMC,Carboxymethyl cellulase)共同作用阳性克隆15个。通过已测序MF3木聚糖酶阳性克隆酶学活性分析,该木聚糖酶在最适应pH 4.5, 40℃条件下,酶活力为79.287μ·mL~(-1)。为进一步研究黄淮白山羊瘤胃内纤维素酶(Cellulase)基因奠定基础。     

Technical note: A wireless telemetric method of monitoring clinical acidosis in dairy cows

Ruminant animals convert forage containing cellulose by bacterial fermentation into nutrients. The health of the bacterial culture in the rumen is essential for the health and productivity of the animal. Over a number of years fistulated animals have been used to study the rumen and its bacterial population. It has been shown that techniques to maintain the pH of the rumen between 7 and 5.5 pH are essential for the health of the dairy cow. The rumen pH has been recorded by using sensors suspended in the rumen at intervals or exceptionally with data recorders. However, fistulation of an animal requires surgery and is only suitable for a few research animals. This paper describes the development of a telemetric bolus that measured and recorded pH continuously. When interrogated by wireless the bolus transmitted the recorded data to an operator standing beside the cow with a receiving station. Boluses were placed in fistulated animals so that a comparison could be made with a laboratory instrument. Data are presented that show a close correlation between the calibrated laboratory instrument and the bolus at time intervals when the instrument was inserted. From this it can be assumed that the bolus accurately records the temporal variation in rumen pH. Data are presented to show the diurnal change in rumen pH over a 6-week period. Methods of increasing the lifetime and accuracy of the bolus are discussed.     

出版生态系统进化论

研究了出版生态系统进化的进程,认为出版生态系统经历了原始出版生态系统、古代出版生态系统、近代出版生态系统和现代出版生态系统四个阶段。出版生态系统进化的最根本动力是社会需要,传播技术的发展为出版生态系统的进化提供了技术支持,而出版机构之间的竞争则是出版生态系统进化的内在动力。出版生态系统的进化遵循协同进化的规律,出版生态系统的复杂性逐步提高的规律,新旧媒体竞争与共生的规律,遗传、变异与社会选择的规律。只有遵循进化规律,才能实现与社会的协同进化。     

Direct-fed microbes: A tool for improving the utilization of low quality roughages in ruminants

For many years, ruminant nutritionists and microbiologists have been interested in manipulating the microbial ecosystem of the rumen to improve production efficiency of different ruminant species. Removal and restriction of antibiotics subtherapeutic uses from ruminant diets has amplified interest in improving nutrient utilization and animal performance and search for more safe alternatives. Some bacterial and fungal microorganisms as a direct-fed microbial(DFM) can be the most suitable solutions. Microorganisms that are commonly used in DFM for ruminants may be classified mainly as lactic acid producing bacteria(LAB), lactic acid utilizing bacteria(LUB), or other microorganism's species like Lactobacillus, Bifidobacterium, Enterococcus, Streptococcus, Bacillus, Propionibacterium, Megasphaera elsdenii and Prevotellabryantii, in addition to some fungal species of yeast such as Saccharomyces and Aspergillus. A definitive mode of action for bacterial or fungal DFM has not been established; although a variety of mechanisms have been suggested. Bacterial DFM potentially moderate rumen conditions, and improve weight gain and feed efficiency. Fungal DFM may reduce harmful oxygen from the rumen, prevent excess lactate production, increase feed digestibility, and alter rumen fermentation patterns. DFM may also compete with and inhibit the growth of pathogens, immune system modulation, and modulate microbial balance in the gastrointestinal tract. Improved dry matter intake, milk yield, fat corrected milk yield and milk fat content were obtained with DFM administration. However, the response to DFM is not constant; depending on dosages, feeding times and frequencies, and strains of DFM. Nonetheless, recent studies have supported the positive effects of DFM on ruminant performance.