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1.
应用DGGE分析秸秆日粮对奶牛瘤胃细菌群落的影响 总被引：1，自引：0，他引：1
【目的】通过与苜蓿日粮比较,揭示秸秆日粮模式下瘤胃固液相细菌群落的独特结构。【方法】选择12头健康且体重相似的装有永久瘤胃瘘管的中国荷斯坦奶牛,分别饲喂以玉米秸秆（CS）和苜蓿、羊草、青贮玉米三者混合物（MF）为粗饲料组成的日粮,正饲期第13周连续3 d分12个时间点采集瘤胃固、液相内容物样品。提取微生物DNA后,利用PCR结合变性梯度凝胶电泳技术（DGGE）分析细菌群落结构,并进行聚类分析及差异条带的测序分析。【结果】与MF组相比,CS组奶牛瘤胃固、液相细菌DGGE图谱条带的数目和光密度均有一定差异,两处理组都各有一些稍显优势的条带,CS组优势条带要少于MF组。与MF组相比,CS组液相细菌的香浓多样性指数无差异（P＞0.05）,固相细菌香浓多样性指数显著降低（P＜0.01）;通过对差异条带进行测序,发现与MF组相比,CS组中瘤胃细菌Prevotella sp.、Acetivibrio ethanolgignens和Clostridium sp.减少,并且大量来源于Bacteroidetes、Firmicutes、Tenericutes和Proteobacteria等菌门的未培养细菌有所变化。【结论】秸秆日粮条件下奶牛瘤胃存在独特的细菌群落结构,细菌多样性较低。 相似文献
2.
Five lactating Holstein cows in a 5×5 Latin square experiment were fed five high-concentrate total mixed rations(TMRs) to investigate the effects of step-wise improvement of forage combination on ruminal and milk fatty acid profiles. The ratio of concentrate to forage was fixed as 61:39, and the step-wise improvement of forage combination was applied as: TMR1, a ration containing corn stover; TMR2, a ration containing corn stover and ensiled corn stover; TMR3, a ration containing ensiled corn stover and Chinese wild ryegrass hay(Leymus chinensis); TMR4, a ration containing the ryegrass hay and whole corn silage; TMR5, a ration containing the ryegrass hay, whole corn silage and alfalfa hay. The TMRs were offered to the cows twice daily at 0700 and 1900 h. The entire experiment was completed in five periods, and each period lasted for 18 days. Diurnal samples of rumen fluids were collected at 0100, 0700, 1300 and 1900 h(day 16); 0300, 0900, 1500 and 2100 h(day 17); and 0500, 1100, 1700 and 2300 h(day 18). The step-wise improvement of forage combination increased energy and crude protein contents and decreased fibre content. As a result, the step-wise improvement of forage combination increased dry matter intake and milk yield(P0.05). The step-wise improvement increased dietary content of linolenic acid(C18:3 n-3), but did not alter dietary proportions of palmitic acid(C16:0), stearic acid(C18:0), oleic acid(C18:1 cis-9), linoleic acid(C18:2 n-6) and arachidic acid(C20:0). In response to the forage combination, ruminal concentration of C16:0, C18:2 n-6 and C18:3 n-3 linearly increased against their dietary intakes(P0.10). The step-wise improvement increased milk contents of C10:0, C12:0, C14:0, C16:0, C18:2 n-6 and C18:3 n-3(P0.10) and decreased milk contents of C18:0 and C18:1 cis-9(P0.05). Milk yields of C16:0, C18:1 cis-9, C18:2 n-6 and C18:3 n-3 were linearly increased by the increase of these fatty acids in the rumen(R2≥0.79, P0.05), and milk yields of C18:2 n-6 and C18:3 n-3 were also positively correlated with dietary intake of these fatty acids(R2≥0.85, P0.05). The step-wise improvement increased the transfer efficiencies from feed to milk for C18:2 n-6 from 11.8 to 14.2% and for C18:3 n-3 from 19.1 to 22.3%. In a brief, along with the step-wise improvement of forage combination, more dietary linoleic and linolenic acids might escape microbial hydrogenation in the rumen and consequently accumulated in milk fat though these fatty acids were present in low concentrations in ruminal fluids. The step-wise improvement of forage combinations could be recommended as a dietary strategy to increase the transfer efficiency of linoleic and linolenic acids from feed to milk. 相似文献
3.
基于DGGE和T-RFLP分析采食不同粗饲料梅花鹿瘤胃细菌区系 总被引：2，自引：0，他引：2
【目的】细菌区系在梅花鹿（Cervus nippon）瘤胃发酵中发挥着重要作用,然而有关梅花鹿瘤胃细菌区系的研究鲜有报道。研究梅花鹿瘤胃细菌区系,为梅花鹿瘤胃发酵调控提供分子生物学依据。【方法】选取4头2岁龄的装有永久性瘤胃瘘管的成年雄性梅花鹿为研究对象,分别饲喂以柞树叶（OL组,梅花鹿A和B）和玉米秸秆（CS组,梅花鹿C和D）为主要粗饲料的日粮,持续饲喂30 d。通过瘤胃瘘管取瘤胃内固液混合物,提取瘤胃微生物基因组DNA。扩增瘤胃细菌16S rRNA基因V3区以及16S rRNA基因,分别用于DGGE和T-RFLP分析。DGGE图谱进行聚类分析,并切取优势条带进行克隆测序,鉴定瘤胃内细菌组成。根据T-RFLP图谱结果计算细菌群落的多样性、优势度、均匀度和丰富度,通过Microbial Community AnalysisⅢ（MiCAⅢ）数据库推测T-RFs可能代表的微生物种类,并进行T-RFLP图谱的聚类分析。【结果】DGGE图谱聚类表明,CS组和OL组瘤胃细菌区系相似性低于65%,表明粗饲料种类影响梅花鹿瘤胃细菌区系。OL组梅花鹿A和B的DGGE图谱相似度大于70%,CS组梅花鹿C和D的DGGE图谱相似性大于75%,而且同组不同个体之间瘤胃细菌区系存在差异。OL组和CS组分别获得20和24个DGGE特异性条带。序列分析表明,CS组条带可归类为拟杆菌门、厚壁菌门和变形菌门,而OL组条带可归类为拟杆菌门、厚壁菌门、变形菌门和互养菌门。OL组与CS组中存在大量Prevotella spp.,但不同组中Prevotella spp.在种水平组成不同,主要纤维降解菌为Clostridium spp.与Eubacterium spp.。T-RFLP结果显示,梅花鹿D（CS组）具有最高的丰富度、多样性、均匀度和最低的优势度,梅花鹿A和B的各项指数相近但低于梅花鹿D,说明OL组中的粗饲料（柞树叶）影响瘤胃中微生物的相对生物量。梅花鹿C和D的各项指数相差较大而且梅花鹿C的指数低于梅花鹿A和B,表明同组不同个体之间存在差异。81、214、272和308 bp的T-RFs为OL组优势条带,90、95、175、273和274 bp的T-RFs为CS组优势条带,161、259、264、266和284 bp的T-RFs为共同条带。根据MiCAⅢ结果,这些T-RFs代表细菌归类于拟杆菌门、厚壁菌门、变形菌门和酸杆菌门。T-RFs图谱聚类表明,4头梅花鹿T-RFs聚为两类,粗饲料来源影响梅花鹿瘤胃细菌T-RFs图谱特征,其中梅花鹿A、B和C的T-RFs特征条带图谱相似。【结论】Prevotella spp.是梅花鹿瘤胃优势细菌,但不同粗饲料影响梅花鹿瘤胃细菌区系组成。 相似文献
4.
在农村条件下,为了对比玉米秸青贮与添加尿素后饲喂奶牛的效果,又为了研究野干草饲喂效果,于1979年4月25日至6月25日在山西省山阴县山阴城公社农场,利用纯种小荷兰牛及其杂种母牛,分三组牛进行了产奶观察,每日每头平均产奶量玉米秸青贮组为9.3±2.6公斤,尿素青贮组为9.5±4.1公斤,野干草组为9.5±3.9公斤(P>0.05),每头每日麻饼采食量玉米秸青贮组较其他二组多吃1公斤。干物质食入量以野干草组较高。泌乳划间每头每日体重变化情况是:青贮组-28克,尿素青贮组5.7克,野干草组-197克。通过试验可以看出,尿素青贮可以节省麻饼,并可增加体重。但玉米秸青贮较野干草粗硬,适口性也较差。三组牛的泌乳稳定性平均为96.2%,显示了小荷兰牛的优越性。 相似文献
5.
为了解斑马鱼Danio rerio肠道细菌多样性,采用细菌分离纯化、16S r DNA基因分子鉴定技术,对斑马鱼肠道细菌进行PCR-SSCP分析。结果表明:从斑马鱼肠道分离纯化出12株细菌,分别命名为Zf1、Zf2、Zf3、Zf4、Zf5、Zf6、Zf7、Zf8、Zf9、Zf10、Zf11和Zf12,其中对7株分离菌构建p MD18-T/16S r DNA的阳性克隆测序显示,Zf1、Zf11菌株与Aeromonas veronii的16S rDNA序列一致性为99%,Zf4、Zf8菌株与Sphingomonas sp.的一致性为99%,Zf5菌株与Bacillus subtilis的一致性为99%,Zf7菌株与Aeromonas sp.M10的一致性为99%,Zf10菌株与uncultured bacterium clone GI3-M-5-G01的一致性为92%;16S r DNA分子鉴定表明,Zf1、Zf7和Zf11属于气单胞菌属Aeromonas,Zf4、Zf8属于鞘氨醇单胞菌属Sphingomonas,Zf5属于芽孢杆菌属Bacillus,Zf10为一种新菌株;采用PCR-SSCP技术对12株细菌16S r DNA基因V3区进行多态性分析,结果显示,斑马鱼肠道细菌16S r DNA基因V3区存在多态性,其中Zf1与Zf11菌株带型一致,Zf4与Zf8菌株带型一致。本研究结果可为揭示鱼类肠道菌群结构对其生命活动的影响提供科学参考。 相似文献
6.
厌氧氨氧化反应器载体生物膜细菌多样性的研究 总被引：1，自引：0，他引：1
采用细菌16SrRNA通用引物1055F／1392R-GC获得的PCR产物进行变性梯度凝胶电泳（DGGE）,分析了两个厌氧氨氧化反应器在不同运行时间其载体生物膜上的细菌多样性。结果表明,两个反应器在不同运行时间其细菌种群多样性有一定差异。DGGE优势条带序列系统发育分析结果表明,反应器载体生物膜上的细菌类群主要是陶厄氏菌属Thauera、鞘氨醇单胞菌属Sphingomonas,外硫红螺旋菌科Ectothiorho．dospiraceae、酸杆菌门Chloroflexi、绿弯菌门Acidobacteria及不可培养细菌。当反应器运行208d时,水体中氨氮和亚硝态氮的去除率维持较高水平,两者去除率之比为1．1,表明反应器内发生了厌氧氨氧化反应。针对厌氧氨氧化细菌16SrRNA基因引物Pla46F／Amx368R—GC获得的PCR产物,采用DGGE技术对载体生物膜上的厌氧氨氧化细菌进行了检测。DGGE优势条带序列分析结果表明,在反应器中富集得到的厌氧氨氧化细菌分别与PlanctomyceteKSU-1、CandidatusJetteniaasiatica的相似性均为96％,可以认为它们是反应器内起厌氧氨氧化作用的主要细菌。 相似文献
7.
《东北农业大学学报(英文版)》2020,(2)
The major objective of this study was to determine the effect of corn straw or mixed diet on the small molecule metabolites of liver and milk production of healthy Chinese Holstein cows during lactation.In this study,metabolomic methods based on ultra performance liquid chromatography-mass spectrometry (LC-MS) were used to study the liver metabolites of dairy cows fed on corn straw diet or mixed diet.Ten healthy Chinese Holstein cows were randomly assigned to two groups,under the same management condition,fed different diets respectively,corn straw group (CS) or a mixture of alfalfa hay and Chinese wild rye hay mixed forage group (MF).All the cows were fed for 8 weeks and recorded body weight,dry matter intake,body condition score,fat,protein,lactose,milk yield and the total solids.Livers were sampled from each cow through a liver puncture needle for analysis of a significant difference in small molecule metabolites in cow liver samples from the two different diets.The results suggested that different diet types had significant effects on liver metabolism and milk components in dairy cows.The contents of milk fat,the total solids,milk protein,lactose,dry matter intake (DMI),milk yield,milk protein (%),lactose (%) and milk fat (%) of the corn straw group were significantly lower than those of the mixed forage group (p0.05);the contents of phosphatidylcholine (PC),histidine,hypoxanthine and mridine in liver tissues of the corn straw group were significantly lower than those in the mixed forage group (p0.05);acetylcarnitine,uric acid,triacylglycerol (TG),acetal phosphatidylcholine (plasmenyl-PC),acetalphosphatidylethanolamine (plasmenyl-PE) and sphingomyelin (SM) of the corn straw group were significantly higher than those in the mixed forage group (p0.05).In summary,cows fed on mixed forage diet significantly improved milk yield and lactation performance clearly. 相似文献
8.
全收粪法与尼龙袋法测定幼羊全混合日粮养分消化率的相关性研究 总被引：6，自引：0，他引：6
选用 4只正常幼公羊及 4只装有永久性瘤胃瘘管的幼公羊 ,按 4× 4拉丁方设计 ,分别用全收粪法与尼龙袋法测定不同加工处理组合对幼羊全混合日粮 ( TMR)干物质 ( DM)、有机物( OM)、粗蛋白 ( CP)表观消化率及瘤胃 4 8h消失率的影响 ,并分析其相关性。试验结果表明 ,在含玉米秸的 TMR中 ,以尿素精料等氮代替豆饼对日粮 DM,OM,CP的表观消化率及瘤胃消失率均无明显不利影响 ( P>0 .0 5) ;在含尿素精料的 TMR中 ,玉米告的碱化处理使日粮 DM,OM的表观消化率及瘤胃消失率分别提高了 12 .90 % ( P<0 .0 1)后 ,12 .78 ( P<0 .0 1)以及 8.65( P<0 .0 5)和 8.17 ( P<0 .0 5) ,而 CP的表观消化率及瘤胃消失率均无明显改善 ( P>0 .0 5) :对含尿素精料及碱化玉米秸的 TMR进行颗粒化加工 ,并未明显影响日粮 DM,OM,CP的表观消化率及瘤胃消失率 ( P>0 .0 5)。用全收粪法与尼龙袋法测得全混合日粮 DM,OM,CP的表观消化率与瘤胃 4 8小时消失率呈强的正相关 ( P<0 .1)。因而在具备瘤胃瘘管羊时 ,可用尼龙袋法简化 TMR营养价值评定 相似文献
9.
旨在阐释奶牛日粮添加淀粉对奶牛乳脂及瘤胃细菌菌群变化的影响。选取4头体况相近、健康的泌乳期中国荷斯坦奶牛,试验开始前以基础日粮饲喂并作为对照,饲喂7 d;试验期每头奶牛日粮中添加1.5 kg·d-1玉米淀粉,饲喂15 d。结果表明,日粮中添加淀粉后,牛奶乳脂率极显著降低(P<0.01)。瘤胃细菌研究表明,在门水平上共检测到28个菌门,玉米淀粉导致瘤胃芽单胞菌门(Gemmatimonadetes)、软壁菌门(Tenericutes)丰度极显著降低(P<0.01),装甲菌门(Armatimonadetes)、酸杆菌门(Acidobacteria)、蓝藻门(Cyanobacteria)丰度显著降低(P<0.05),厚壁菌门(Firmicutes)丰度显著增加(P<0.05)。在属水平上共检测到383个菌属,其中90个菌属发生显著变化。玉米淀粉导致醋酸杆菌属(Acetobacter)、乳酸杆菌属(Lactobacillus)、小球菌属(Pediococcus)、明串珠菌属(Leuconostoc)、毛螺旋菌属-1(Lachnoclostridium-1)、瘤胃球菌属-1(Ruminococcus-1)、普雷沃氏菌属-7(Prevotella-7)等丰度极显著增加(P<0.01),厌氧弧菌属(Anaerovibrio)、肠球菌属(Enterococcus)、栖水菌属(Enhydrobacter)等丰度极显著降低(P<0.01)。本试验结果表明,奶牛日粮中添加一定量的玉米淀粉对瘤胃细菌多样性和种类分布均匀度均无显著影响,但其促进了大部分产酸菌群的增殖。 相似文献
10.
应用PCR—DGGE技术对盘锦某滩涂四角蛤蜊Mactra venerformis体内的细菌多样性进行了分析。使用SDS裂解法提取样品的总DNA,采用大多数细菌通用引物F338GC／RS18从总DNA中成功扩增出16SrDNA片段,然后对PCR产物进行DGGE分析,并将DGGE图谱上部分条带回收、再扩增、克隆和测序：将所测序列在GenBank核酸数据库中进行检索,用BLASTN分析DNA序列获得相似性最近的细菌。DGGE图谱显示,四角蛤蜊体内的细菌种类比较丰富,且不同时间样品细菌的优势菌群结构有一定的差异。将所测条带序列进行比对,结果表明,细菌种群中包括支原体属Mycoplasma、假单胞菌属Pseudomonas、弧菌属Vibrio、红球菌属Rhodococcus和鞘氨醇单胞菌属Sphingomonas及不可培养的细菌。 相似文献
11.
瘤胃微生物基因组文库中BAC末端序列分析 总被引：2，自引：1，他引：1
基于前期从瘤胃微生物基因组文库中筛选的功能酶克隆菌,利用T7和pIBRP引物,测定功能酶克隆菌的BAC末端序列,并利用NCBI Blast系统对BAC末端序列进行分析.结果表明:共得到26条BAC末端序列,经Blast比对分析,与已知编码基因的匹配度低,而大部分BAC末端序列与阪崎肠杆菌和环境中的微生物匹配度高,说明瘤胃中的微生物与其它环境中的微生物具有一定的相似性,进一步丰富了对瘤胃微生物的认识. 相似文献
12.
应用变性梯度凝胶电泳和16S rDNA序列分析对山羊瘤胃细菌多样性的研究 总被引：26，自引：0，他引：26
以取自3头安装有永久性瘤胃瘘管的土种山羊的瘤胃内容物为材料, 经过DNA抽提和PCR扩增, 扩增产物利用变性梯度凝胶电泳技术(DGGE，一种DNA指纹技术)分析瘤胃细菌在两种日粮条件下的多样性。同时利用基因序列分析技术，分析了16个在DGGE胶上有匹配带的克隆的16S rDNA序列，并与现有的数据库进行了比较。结果表明，饲喂基础日粮时3头山羊瘤胃内容物的DGGE图谱有一定的相似性(43%～55%)；饲料中添加大豆黄酮一定程度上影响了瘤胃细菌的组成，DGGE谱带变化程度分别为1号36%、2号46%、3号30%。基因序列分析表明，DGGE图谱中优势条带的16S rDNA基因序列中有5个基因序列与基因数据库登录的相关序列的相似性大于97%，8个基因序列的相似性在90%～96%，余下的低于90%。相似性大于97%的5个克隆中，只有1个被鉴定为Prevotella sp.，其余4个都属于未被鉴定的瘤胃细菌。 相似文献
13.
Akbar Nikkhah 《Russian Agricultural Sciences》2013,39(3):206-213
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. 相似文献
14.
《东北农业大学学报(英文版)》2016,(4):40-46
The main purpose of this study was to determine the effect of a corn straw or mixed diet on milk production, milk composition and the expression of genes associated with lactation in mid-lactation Chinese Holstein cows. In this study, 10 healthy Chinese Holstein cows were randomly assigned to two groups and fed with different diets respectively, corn straw(CS) or mixed forage(MF) diet. CS group was fed roughage consisting of 53.8% corn straw only and the forge to concentrate(F : C) ratio [dry matter(DM)] was about 40: 60. MF group was fed roughage consisting of 3.7% Chinese wildrye and 23.4% alfalfa hay, the forge to concentrate(F : C) ratio(DM) was 70: 30. All the cows were fed 8 weeks and body weight, dry matter intake, body condition score, fat, protein, lactose, milk yield, total solid and somatic cell count(SCC) were recorded. Quantitative real-time PCR(q RT-PCR) was used to analyze cow mammary gland samples representing two different diets. The results suggested that different diet types had significant effects on milk yield, lactose, milk fat, milk protein, dry matter intake and somatic cell count in dairy cows, and cows fed MF diet improved milk production and lactation performance clearly(P0.05). In addition, m RNA expression of genes ACC, m TOR, STAT5, CSN2, PPARγ, FABP3 and PTEN in MF group was extremely significantly higher than that in CS group(P0.05). m RNA expression of AKT1, FAS, SCD and SREBP1 c in MF group was significantly higher than that in CS group(P0.01). In summary, the milk yield and composition in mixed forage group were significantly improved than those in corn straw group. 相似文献
15.
日粮添加纳豆芽孢杆菌对断奶后犊牛胃肠道纤维分解菌的影响 总被引：7，自引：2，他引：5
研究日粮中添加纳豆芽孢杆菌对断奶后犊牛瘤胃及肠道中主要的纤维分解菌琥珀酸丝状杆菌(Fibrobacter succinogenes)、黄色瘤胃球菌(Ruminococcus flave faciens)、白色瘤胃球菌(Ruminobacter albus)、溶纤维丁酸弧菌(Butyrivibrio fibrisolvens)和脂解厌氧孤杆菌(Anaerovibrio lipolytica)数量的影响.选取8头断奶犊牛,处理组犊牛日粮中添加含菌量为1010 CFU的纳豆枯草芽孢杆菌菌液.采集犊牛瘤胃食糜提取总DNA,利用种属特异性引物和实时荧光定量PCR计算菌群数量变化.结果表明,脂解厌氧弧杆菌是对照组犊牛消化道中的优势纤维分解菌;琥珀酸丝状杆菌、白色瘤胃球菌、溶纤维丁酸弧菌存在于除十二指肠之外的其他肠道中.与对照相比,在处理组瘤胃、空肠和回肠中都检测到了黄色瘤胃球菌,犊牛其他肠道部位的纤维分解菌的数量均有增加,回肠中琥珀酸丝状杆菌、白色瘤胃球菌及溶纤维丁酸弧菌的数量分别比对照组增加了69.3%、86.2%和76.5%.本研究表明纳豆芽孢杆菌促进了以上几种纤维分解功能菌群在断奶后犊牛消化道中的定植和生长. 相似文献
16.
为研究九孔鲍(Haliotis diversicolor supertexta)育苗期养殖水体细菌的群落结构,用细菌通用引物构建了细菌16S rRNA基因克隆文库.从文库中随机挑选31个克隆子进行限制性片段长度多态性(RFLP)分析,得到20个不同的RFLP带型.对代表性克隆子进行测序,序列分析和系统进化分析结果表明鲍苗养殖池水体中细菌遗传多样性非常丰富.主要分为3大类群:γ-变形菌纲、α-变形菌纲和黄杆菌纲细菌,分别占58%、32%和10%.γ-变形菌纲细菌中以弧菌最多,包括已知的鲍病原弧菌,其次是海洋螺菌目细菌.α-变形菌纲细菌主要与GenBank库中未培养的克隆子序列最相似,其中红细菌科细菌最丰富,占所分析克隆子数目的26%.本研究结果表明九孔鲍育苗期养殖水体中存在大量未培养的、未知菌属的细菌. 相似文献
17.
饲料玉米中优质乳酸菌的分离和鉴定 总被引：1，自引：1，他引：0
[目的]从饲料玉米中筛选适合做青贮饲料添加剂的高效乳酸菌。[方法]用MRS＋CaCO3固体培养基筛选乳酸菌,经形态学和生理生化试验进行初步鉴定,测定其产酸效率;挑选出12株产酸率强的乳酸菌进行耐盐和耐酸能力的测定,并对其进行16 S rDNA鉴定。[结果]从饲料玉米中共分离得到44株乳酸菌,12株产酸能力强的菌株经生理生化试验鉴定分别属于明串珠菌属、乳杆菌属和肠球菌属,且12株菌株都具有良好的耐盐、耐酸能力。经16 S rDNA鉴定：A4、B9、B11、B12和B14为植物乳杆菌;A1、A2、A7、A11和B8为肠膜明串珠菌葡聚糖亚种;A8和A9为兼性肠球菌。[结论]从饲料玉米中筛选出具有较强产酸能力的乳酸菌,作为青贮饲料添加剂。 相似文献
18.
【目的】建立一种适用于瘤胃主要纤维降解细菌的RT-PCR定量检测方法,通过培养技术监测瘤胃纤维降解细菌在不同环境下的数量变化,为深入研究反刍动物瘤胃发酵机理以及对纤维素资源的有效利用提供技术支持。【方法】分别以Fibrobacter succinogenes、Ruminococcus flavefaciens与Ruminococcus albus 的16SrDNA为靶序列设计相应的引物,建立SYBR GreenⅠRT-PCR定量体系。【结果】本研究所采用的引物及相应的PCR反应体系具有较高的特异性和灵敏度,检测极限可达50拷贝。采用RT-PCR方法检测瘤胃纤维降解细菌的定量结果与传统计数结果具有一致的变化趋势,相关性较高（r2=0.9591,P＜0.05）,表明RT-PCR定量检测方法可以较为准确、迅速的检测绵羊瘤胃纤维降解菌群的数量随环境变化的情况。【结论】本研究所建立的RT-PCR检测方法能够较准确反映瘤胃纤维降解细菌数量的变化。 相似文献
19.
《农业科学学报》2017,(4)
Dry matter intake(DMI) prediction models of NRC(2001),Fox et al.(2004) and Fuentes-Pila et al.(2003) were targeted in the present study,and the objective was to evaluate their prediction accuracy with feeding trial data of 32 lactating Holstein cows fed two total mixed rations with different forage source.Thirty-two cows were randomly assigned to one of two total mixed ration groups:a ration containing a mixed forage(MF) of 3.7%Chinese wildrye,28.4%alfalfa hay and 26.5%corn silage diet and another ration containing 33.8%corn stover(CS) as unique forage source.The actual DMI was greater in MF group than in CS group(P=0.064).The NRC model to predict DMI resulted in the lowest root mean square prediction error for both MF and CS groups(1.09 kg d~(-1) vs.1.28 kg d~(-1)) and the highest accuracy and precision based on concordance correlation coefficient for both MF and CS diet(0.89 vs.0.87).Except the NRC model,the other two models presented mean and linear biases in both MF and CS diets when prediction residuals were plotted against predicted DMI values(P0.001).The DMI variation in MF was caused by week of lactation(55.6%),milk yield(13.9%),milk fat percentage(7.1%) and dietary neutral detergent fiber(13.3%),while the variation in CS was caused by week of lactation(50.9%),live body weight(28.2%),milk yield(8.4%),milk fat percentage(5.2%) and dietary neutral detergent fibre(3.8%).In a brief,the NRC model to predict DMI is comparatively acceptable for lactating dairy cows fed two total mixed rations with different forage source. 相似文献
20.
[目的]了解野生秦岭羚牛瘤胃产甲烷古菌的组成及其多样性。[方法]提取野生秦岭羚牛瘤胃内容物总DNA,选用产甲烷菌特异性引物Met86F和Met1340R,对总DNA进行16S rRNA特异性扩增,构建秦岭羚牛瘤胃产甲烷古菌16S rRNA克隆文库,对阳性克隆进行PCR-RFLP(限制性内切酶片段长度多态性)分析,并对HaeⅢ酶切带谱不同的菌液进行测序,构建系统发育树。[结果]根据酶切带谱分析和测序结果的不同,将随机挑取的105个阳性克隆归为14个不同的可操作分类单元(OTUs)。系统发育分析表明,这些克隆序列均位于广域古菌门(Euryarchaeota),隶属甲烷杆菌科(Methanobacteriaceae,65.71%)、Methanomassiliicoccus(29.52%)和Methanosarcinaceae(4.76%)3个科。其中有57个序列与可培养菌相似度在97%以上,分属于Methanobrevibacter millerae、Methanobrevibacter olleyae和Methanobrevibacter thaueri。其余48个序列与未培养菌相似度较高,占11个OTUs。[结论]野生秦岭羚牛瘤胃产甲烷古菌多样性比较丰富,且可能存在新的分类单元。 相似文献