大肠杆菌耐药基因定位及耐药质粒消除

对采集的9株野生型大肠杆菌在药敏试验的基础上,进行了耐药基因定位。结果表明,4个菌株的氨苄青霉素耐药基因位于质粒上,不同畜群来源菌株之间耐氨苄青霉素质粒存在差异。用中草药艾叶的乙醇提取物和蒸馏提取物对大肠杆菌庆大霉素耐药性及耐药质粒进行了消除试验,结果艾叶乙醇提取物的消除率最高可达69.4%。     

庆阳市采用塑料大棚发酵畜禽粪污模式初探

为了提高粪污发酵速度、缩短发酵时间,减少环境对粪污的承载和消纳能力,笔者通过采用塑料大棚模式发酵粪污,以提高粪污内部温度,添加一定的微生物菌剂,采用高温好氧堆积发酵,在西北气候条件下,使小型养殖场(合作社)粪污发酵比常温堆积发酵时间缩短了40～100 d,使粪污尽快得到还田利用,减少了环境对粪污的承载力。     

混合比例和添加剂对菊苣与青贮玉米混合青贮品质的影响

探讨不同混合比例和添加剂对菊苣和青贮玉米混合青贮饲料品质的影响,为调制高质量的混合青贮饲料提供理论依据。以菊苣和青贮玉米为原料,按质量比0∶1、1∶3、1∶1、3∶1和1∶0 (分别用0C1M、1C3M、1C1M、3C1M、1C0M表示)进行混合青贮,并分别设置3个添加剂处理,即零添加、5 g·t^-1乳酸菌+5 g·t^-1纤维素酶(LX)和10 g·t^-1乳酸菌+5 g·t^-1纤维素酶(2LX),青贮60 d后测定混合青贮饲料的营养成分和发酵品质。结果显示,菊苣与青贮玉米混合比例为0∶1和1∶1时青贮饲料的感官评价优于其余3种混合比例的,而且添加剂处理感官评定优于零添加处理的。菊苣和青贮玉米混合青贮可以形成养分互补,有助于均衡青贮饲料整体营养,在青贮原料中添加添加剂则可以提高青贮饲料发酵品质。混合青贮饲料的营养价值随菊苣比例增加而显著提高,但是发酵品质在菊苣混合青贮比例高于1∶1时显著降低。综合判定菊苣和青贮玉米1∶1混合时其青贮饲料品质最佳,其中又以1C1M/2LX处理最好,纤维组分(NDF和ADF)和氨态氮/总氮含量较低而粗蛋白和乳酸含量较高。     

Effect of Different Domestic Alfalfa Adding Content on Nutritional Quality of Local Fresh Milk

Domestic alfalfa supply has the obvious price advantage in the local dairy farms,but its feasible amount of feeding and the effect on the quality of fresh milk are still unclear for a lack of scientific experimental evidence. The alfalfa growed in Daqing city, Heilongjiang province was used in the present study,and one-year feeding experiment was performed to analyze the effect of alfalfa on the quality of fresh milk in the local 9 large-scale dairy farms. The results showed that compared with control group,the nutrient of fresh milk were not significantly improred when the amout of alfalfa was 3 kg/d (P >0.05).While the cude protein and dry matter of fresh milk were significantly increased (P <0.05) when the amount of alfalfa addition in the diet was 6 kg/d, but the milk fat and lactose percentage were not significantly affected (P <0.05). Moreover,the alfalfa addition in diet resulted in a significantly increase of unsaturated fatty acid percentage (P <0.05) and optimization of fatty acid composition of the fresh milk. In conclusion,it was helpful to improve the nutritional quality of fresh milk by changing the alfalfa amount of 3 kg/d,which was commonly used at present in dairy farms,to be 6 kg/d.     

Cloning,Expression and Bioinformatics Analysis of Enterococcus faecalis from Northeast Black Bear

In order to detect Enterococcus faecalis endocarditis antigen (EfaA) of bear that was used to disclose the infected Northeast Black bear immediately, a pair of PCR primers was synthesized by EfaA gene of Enterococcus faecalis that was recorded in GenBank (accession number:U03756.1) and the target fragment was 689 bp. The PCR product was cloned by pMD19-T vector, then was transferred to Escherichia coli DH5α competent cells and the positive clones were filtered. Recombinant plasmid (pMD19-T-EfaA) was extracted. Identification of PCR and digestion, sequencing, the structure prediction of proteins were operated. The results showed that EfaA gene was cloned successfully, and the gene homology with ATCC 29212 was 100.0%. pMD19-T-EfaA was constructed successfully, structure of proteins was predicted. This study provided theoretical basis for diagnostic methods of Enterococcus faecalis and laid basis for prevention and control of Northeast Black bear disease.     

热应激对公兔睾丸组织形态和抗氧化指标及精液品质的影响

选择体况基本一致的成年新西兰公兔12只,采用对比试验设计安排试验,试验组即高温(31±2℃)热应激组,对照组即适温(18±2℃)非热应激组,每组6个重复,每重复一只公兔,探索高温环境对公兔睾丸组织形态、抗氧化物活性和精液品质的影响。结果表明:高温环境可使兔的采精量显著下降(P<0.05),精子的活力和密度显著降低(P<0.05);睾丸组织细胞严重损伤、数量减少;睾丸组织中丙二醛(MDA)含量显著增加(P<0.05);超氧化物岐化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)活性和总抗氧化能力(T-AOC)显著降低(P<0.05)。结论:热应激影响公兔的精液品质,这可能与睾丸组织中抗氧化酶活性降低,自由基生成过多,睾丸组织细胞受损有关。     

微波辅助提取黄芩黄酮的研究

目的：利用微波辅助浸提技术从黄芩中浸提黄酮。方法：采用单因素试验考察了浸提剂、液固比、浸提温度、颗粒粒度、微波功率和浸提时间对黄芩黄酮浸提率的影响。结果：微波辅助提取黄苓黄酮的最佳工艺50％乙醇为浸提剂、液固比为20mL／g、浸提温度为90．0℃、浸提时间为8．0min,颗粒粒度为40目,微波功率为600W,此条件下黄酮的浸提率为99．42％;高于常规回流4h。结论：微波辅助提取技术应用于黄芩黄酮的提取具有省时、高效、节能等优点。     

日粮添加LA和DHA对乳脂脂肪酸含量及比值的影响

本试验选用带有永久性瘤胃、十二指肠和回肠瘘管的泌乳荷斯坦奶牛4头,采用4×4拉丁方试验设计,研究日粮添加亚油酸(LA)和二十二碳六烯酸(DHA)对乳常规组成、消化道各段食糜pH以及乳脂脂肪酸构成的影响.试验结果表明:添加LA和DHA不影响乳蛋白和乳糖含量(P>0.05),而添加DHA有显著降低乳脂含量的趋势(P>0.05);日粮共同添加LA与DHA能提高十二指肠前消化道的pH,但差异不显著(P>0.05),而单独添加DHA显著降低了回肠的pH(P<0.05);日粮单独添加DHA增加乳脂中C23:0脂肪酸的含量,但并不降低乳脂中总饱和脂肪酸量.与对照组相比,LA与DHA共同添加使乳脂中总多不饱和脂肪酸增加了100%(P<0.05).LA与DHA共同添加使乳脂中饱和脂肪酸/不饱和脂肪酸由3.18降低至1.24(P<0.05).添加DFIA使乳脂中总单不饱和脂肪酸/多不饱和脂肪酸由5.94降低至3.00(P<0.05).上述研究结果表明,日粮添加LA和DHA可改变乳脂中脂肪酸的组成和比例,有利于人体健康,但DHA使产奶量有一定程度的降低.     

高效液相色谱法测定盐酸林可霉素注射液的含量

建立盐酸林可霉素注射液含量测定的高效液相色谱法。色谱柱:C_(18)色谱柱(4.6 mm×250 mm,5μm),流动相:0.05 mol/L硼砂溶液(用85%磷酸溶液调节pH值至5.0)∶甲醇∶乙腈=67∶33∶2(V/V),流速:1 mL/min,检测波长:214 nm,进样量:10μL,柱温:30℃。盐酸林可霉素浓度在0.1-2 mg/m L范围内峰面积与浓度的线性关系良好(R~2=0.999 9)。此法简便、快捷、灵敏度高、重现性好。