健康与腹泻仔猪肠道菌群多样性差异分析

探讨腹泻对仔猪肠道菌群变化的影响,以健康仔猪和腹泻仔猪新鲜粪便为研究对象,利用传统平板计数的方法和PCR-DGGE技术比较了不同日龄健康和腹泻仔猪肠道菌群数量差异和菌群结构变化。结果表明不同日龄的仔猪粪便样品中的细菌总数,乳酸杆菌数腹泻组较健康组均有下降,其中21日龄健康与腹泻仔猪的细菌总数差异极显著,乳酸杆菌数差异显著;DGGE指纹图谱聚类分析表明,与其它日龄组相比21日龄健康组与腹泻组样品肠道总细菌和乳酸杆菌菌群结构均相似度最低。说明仔猪发生腹泻引起的细菌数量变化与菌群结构复杂程度变化可能存在一定的相关性。     

致乏库蚊体内菌群结构分析

采用PCR–DGGE技术,分析致乏库蚊雌成虫的带菌情况。无菌条件下研磨体表消毒的致乏库蚊雌成虫,提取细菌总DNA,以通用引物扩增细菌16S r DNA V3区,经DGGE电泳、克隆、测序、比对,确定该蚊体内的优势菌。结果表明,致乏库蚊雌成虫携带的优势菌共有6种,其中1种为派毕梯斯沃巴契亚体(Wolbachia pipientis),另外5种尚未被鉴定,分别隶属于假单胞菌属(Pseudomonas sp.)、埃希氏杆菌属(Escherichia sp.)、沃尔巴克氏体属(Wolbachia sp.)和α–变形纲、γ–变形纲某未知种属。     

阿魏酸对抗生素应激小鼠血清抗氧化性及其肠道微生物的影响

【目的】研究阿魏酸对抗生素应激小鼠的血清抗氧化性及其肠道微生物群落多样性的影响,为阿魏酸微生态制剂研制提供理论基础。【方法】将小鼠分为对照组、抗生素组、抗生素+阿魏酸组,通过各种试剂盒检测小鼠血清中的生化和氧化相关酶类指标,并利用高通量测序分析其肠道微生物群落。【结果】阿魏酸使小鼠的T-SOD和GSH-PX活性比对照组分别提高20.50%和26.27%,并使小鼠的总抗氧化能力比抗生素组提高56.36%,同时通过NOS基因下调信号分子促进肠道消化。抗生素导致小鼠肠道微生物的丰度和多样性显著下降,阿魏酸对该现象无显著干预,但阿魏酸组和抗生素组小鼠分别有215、259个独有的操作分类单元,可见阿魏酸对肠道群落组成造成了显著影响。阿魏酸通过上调壁厚菌门与变形菌门在门水平上的丰度比,并通过促进梭菌属、芽胞八叠球菌属和变形杆菌属等增殖,防止条件致病菌肠球菌属过度繁殖,改善了肠道的群落组成。【结论】阿魏酸能够提高小鼠血清的抗氧化能力,改变肠道群落结构,通过多方面改善抗生素对小鼠肠道的代谢和炎症反应产生负面的影响。     

芽孢杆菌制剂对凡纳滨对虾Litopenaeus vannamei肠道微生物群落的影响

应用Biolog方法和传统的平板培养方法分析比较了施用芽孢杆菌制剂的虾池(B)和没有施用任何有益菌的虾池(A)在养殖后期凡纳滨对虾肠道微生物群落结构,并用Shannon指数、Simpson指数和McIntosh指数分析了2种群落的代谢功能的差异。2个虾池对虾肠道微生物群落可培养细菌优势菌属都是革兰氏阴性菌;B虾池对虾肠道可培养细菌数量比A虾池的少;但B虾池对虾肠道微生物群落Shannon指数、Simpson指数和McIntosh指数及其微生物群落代谢功能均显著高于A虾池(P<0.05)。结果表明,虾池施用了芽孢杆菌制剂,可促进养殖对虾肠道微生物群落的代谢功能。     

5种海水养殖石首鱼类肠道菌群多样性的比较

为探究海水养殖石首鱼类肠道菌群的结构特征及种间差异,本研究采用基于Illumina Hiseq2500测序平台的高通量测序技术,对福建宁德三都澳养殖的5种石首鱼类(大黄鱼(Larimichthys crocea)、黄姑鱼(Nibea albiflora)、鮸状黄姑鱼(Nibea miichthyoides)、鮸鱼(Miichthys miiuy)、眼斑拟石首鱼(Sciaenops ocellatus))的肠道菌群进行了16S rDNA V3-V4区测序。各样本得到unique tags的数目在20351到43347之间,上述5种鱼类分别得到479、626、603、518和556个OTUs(operational taxonomic units),分类注释结果显示,这些OUT隶属33个门273个属。5种石首鱼类肠道内容物和肠道壁的样品均以变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)和厚壁菌门(Firmicutes)细菌为主要优势菌群,约占总菌量的70%,在大黄鱼肠道菌群中,螺旋菌门细菌占比达26.19%,也是其主要优势菌群;在属水平上,Bacillus、Photobacterium、Vibrio、Chryseobacterium、Sphingomonas、Pseudomonas等属细菌是5种养殖石首鱼类的主要类别。对养殖石首鱼类的肠道菌群多样性的分析表明,Shannon’s 群落多样性指数：黄姑鱼>鮸状黄姑鱼>眼斑拟石首鱼>鮸鱼>大黄鱼;各种鱼类的肠道内容物菌群的多样性均高于肠道壁;对不同鱼类间的肠道菌群差异性分析显示,大黄鱼与眼斑拟石首鱼之间肠道菌群的相似度要高于黄姑鱼、鮸状黄姑鱼和鮸鱼,而黄姑鱼、鮸状黄姑鱼和鮸鱼之间的相似度较高。综上所述,5种海水养殖石首鱼类肠道菌群中存在有自身特色的核心菌群,肠道菌群结构的差异与种类间的系统进化关系相似,证明肠道菌群结构与宿主遗传因素密切相关。     

Clinical and aetiological aspects of a summer enteritic syndrome associated with the sporulating segmented filamentous bacterium 'Candidatus Arthromitus' in farmed rainbow trout, Oncorhynchus mykiss (Walbaum)

An enteritic syndrome affecting farmed rainbow trout and occurring predominantly in summer has recently been described and related to the massive accumulation of a segmented filamentous bacterium (SFB), ‘Candidatus Arthromitus’, in the digestive tract of fish. Details of the clinical manifestations, the characteristics of the bacterium and the possible aetiology of the disease are presented in this paper. No other bacterial pathogen than ‘Candidatus Arthromitus’ was characterized in trout undergoing the enteritic syndrome. From clinical and histopathological observations, a toxin or toxic product accumulation was suspected in affected trout, and could account for the massive destruction of the intestinal mucosa. However, the origin and aetiological role of the SFB could not be clearly elucidated, although most of the filaments appeared to beviable and to produce and release strings of endospores in the lumen of the gut. The organism could not be cultured in the conditions tested, shared several morphological and structural characteristics with related bacteria described in the intestinal microflora of different vertebrate species, but no attachment structure was definitively recognized. All attempts to detect similar SFB in the fish diet orin the environment of affected fish farms were unsuccessful. It is unclear whether this organism represents a normal and not previously detected inhabitant of the intestine of trout stressed after environmental perturbation, or whether it results directly from external sources of contamination.     

Comparison of conventional and molecular techniques to investigate the intestinal microflora of rainbow trout (Oncorhynchus mykiss)

The concept of the use of probiotic organisms or prebiotic compounds to modify the fish gut microflora is becoming a popular topic for investigation. A major flaw in many such studies is a failure to consider fully the nature of the established microflora, which is to be modified pre-, or probiotically. Since it is widely accepted that a large proportion of bacteria are non-culturable, the use of conventional bacteriological (culture) techniques alone to investigate fish intestinal microflora may be expected to bias results. We report a study designed to investigate the normal intestinal microflora of rainbow trout (Oncorhynchus mykiss) using both conventional bacteriological and molecular methods.Over an 18 month period, the intestinal microflora of a single population of laboratory-raised rainbow trout was investigated. Bacteria isolated using bacteriological techniques were identified using the BiOLOG system and 16S rRNA gene sequencing. Dominant bacteria consistently were Aeromonas sp. and Carnobacterium piscicola, demonstrating that the microflora is stable in fish kept in defined conditions. Restriction Fragment Length Polymorphism (RFLP) and 16S rRNA gene sequence analysis was used to investigate anaerobic and non-culturable bacteria. An obligate anaerobe, Clostridium gasigenes, was shown to be among the dominating intestinal microflora.     

花生连作障碍发生机理研究进展

连作导致花生产量和品质下降,严重影响了花生持续生产。本文结合20年花生长期定位试验研究,从土壤理化性质恶化、化感自毒作用和微生物区系失衡3个方面系统地综述了花生连作障碍的发生机理,认为花生根际微生态系统综合功能失调是造成花生连作障碍的主要原因,并分别就化感作用、根际分泌物与根际微生物的关系、根际微生物与连作障碍的关系和多因子综合考虑等角度对该领域未来的研究方向进行了展望。     

甘露寡糖和益生菌对肉仔鸡生产性能和肠道菌群的影响

试验研究了同时在日粮中添加甘露寡糖和益生菌对肉仔鸡生产性能和肠道菌群的影响,旨在寻找能够替代抗生素的绿色添加剂。选择1日龄的健康AA肉仔鸡400只,随机分为4组,每组4个重复。第1组为对照组,喂基础日粮,第2、3、4组分别在基础日粮中添加0.1%甘露寡糖、0.1%益生菌、0.1%甘露寡糖＋0.1%益生菌。结果表明,与对照组相比,第2、3、4试验组鸡的平均日增重分别提高了4.09%（P〈0.05）、5.84%（P〈0.05）和8.17%（P〈0.05）;料重比分别较降低了2.42%、2.90%和4.35%,但差异均不显著（P〈0.05）;3个试验组的死亡率均显著低于对照组,其中4组较对照组低50.00%（P〈0.05）,2、3组较对照组低25.00%（P〉0.05）和33.33%（P〈0.05）;第2、3、4试验组的大肠杆菌分别较对照组低13.50%（P〈0.05）、22.04%（P〈0.01）和21.53%（P〈0.01）,乳酸杆菌分别比对照组高12.85%（P〈0.05）、16.12%（P〈0.05）和25.09%（P〈0.01）,双歧杆菌分别比对照组高8.52%（P〈0.05）、9.30%（P〈0.05）和8.07%（P〈0.05）。结果提示,甘露寡糖和益生菌对肉仔鸡的增重效果明显,也能有效改善其肠道内的菌群组成。     

酸化剂对早期断奶仔猪胃酸分泌、消化酶活性和肠道微生物的影响

用24头平均体重6.10±0.35kg 的28±1日龄断奶杜×长×大杂交仔猪 ,分成4个处理组 ,分别饲喂玉米—膨化大豆—豆粕型基础饲粮和添加0.6 %HCl、1.5 %柠檬酸、0.25 %复合酸的3种饲粮。结果表明 :在断奶后头2周 ,添加0.6 %HCl、1.5 %柠檬酸、0.25 %复合酸分别提高仔猪日增重5.9 % (P<0.10)、10.5 %(P<0.05)、9.2 %(P<0.05) ,在不同程度上降低了腹泻率 ,对采食量和料肉比没有显著影响 (P>0.10)。添加0.25 %复合酸提高了胃蛋白酶 (P<0.10)和胃酸分泌 (P<0.10) ,显著提高了十二指肠内容物中胰蛋白酶和淀粉酶活性 (P<0.05) ,添加1.5 %柠檬酸有提高上述两种酶活性的趋势 (P<0.15 ,P<0.10) ,但对胃酸和胃蛋白酶分泌没有影响 ,显著降低了结肠大肠杆菌数量 (P<0.05)。此外 ,添加0.25 %复合酸有降低大肠杆菌数量 ,增加乳酸杆菌数量的趋势 (P<0.10)。上述结果表明 ,在早期断奶仔猪饲粮中添加复合酸可刺激胃酸和胃蛋白酶分泌 ,提高十二指肠消化酶活性 ;添加柠檬酸对降低结肠大肠杆菌 ,减少腹泻发生效果显著。添加盐酸可降低仔猪腹泻率 ,提高日增重 ,但效果不及有机酸和复合酸显著