Isolation and Identification of Enterococcus faecalis from Fur-bearing Animals

In order to obtain Enterococcus faecalis from fur animals and evaluate its prebiotic properties,in this study,Enterococcus faecalis was isolated from the feces of healthy adult fur-bearing animals (mink,fox,raccoon dog),identified by morphological observation,biochemical test and 16S rRNA sequence analysis.The growth curve,acid production capacity and antibiotic sensitivity of the Enterococcus faecalis isolates were measured to evaluate their probiotic properties.Some strains were selected to determine their tolerance to temperature,artificial gastric juice and artificial bile salt.The results showed that five strains were Gram-positive,and their biochemical characteristics were basically consistent with the standard strains of Enterococcus faecalis,and they were identified as Enterococcus faecalis by 16S rRNA sequence analysis.The five strains all entered the logarithmic phase at 2 h after culture,and entered the stable phase at 8-10 h,and had weak acid production capacity.The resistance rate of the isolates to tetracycline and levofloxacin was 100%,followed by penicillin (80%),erythromycin (80%),gentamicin (80%) and chloramphenicol (40%).All the isolates were sensitive to ampicillin and vancomycin.Enterococcus faecalis from mink,fox and raccoon dog had strong tolerance to temperature below 60 ℃,artificial gastric juice with pH>3.0 and 0.3%-0.5% concentration of bile salt,but poor tolerance to temperature above 70 ℃,and artificial gastric juice with pH<3.0.In conclusion,five strains of Enterococcus faecalis from fur animals (mink,fox,raccoon dog) were obtained in this study.The isolated strains propagated rapidly,which were suitable for colonization and played a prebiotic role in fur animals' intestines,and had good prebiotic characteristics and stress resistance.They could be used as candidate strains for animal microbiological agents for further study.     

体细胞计数及其在降低奶牛乳房炎发病率方面的应用

介绍奶牛体细胞计数的概念、特征、测量方法、体细胞值所受到的影响及其在乳制品行业的应用,尤其是在降低奶牛乳房炎发病方面,用体细胞值作为一种遗传性状进行选择以提高奶牛对乳房炎抗性的应用。     

小鼠4、8-细胞胚胎单卵裂球体外培养体系的研究

以CZB为基础培养液,培养小鼠4、8-细胞胚胎单卵裂球,研究葡萄糖、牛磺酸和猪输卵管上皮细胞共培养在其体外发育中的作用。结果表明:牛磺酸添加与否对4、8-细胞胚胎单卵裂球的囊胚发育率分别为29%、30%和14%、14%,无显著性差异(P>0.05)。添加葡萄糖后,4、8-细胞胚胎单卵裂球的囊胚发育率分别为36%和19%,有显著提高(P<0.05)。含有葡萄糖而牛磺酸的添加与否对4、8-细胞胚胎单卵裂球的囊胚发育率分别为36%、38%和19%、20%,无显著性差异(P>0.05)。各组内4、8-细胞胚胎单卵裂球形成的囊胚细胞数分别为(10.44±1.24～(12.43±1.18)和(7.57±0.97)～(8.48±1.16),均无显著性差异(P>0.05)。4、8-细胞胚胎单卵裂球与猪输卵管上皮细胞共培养,其囊胚发育率分别为47%和26%,囊胚细胞数分别为(17.57±1.13)和(11.43±0.92),均高于单一培养(P<0.05)。     

胚胎干细胞的研究进展

胚胎干细胞来源于附植前胚胎的内细胞团或附植后胎儿的原始生殖细胞具有发育全能性的细胞。本文从它的研究概况、生物学特性、胚胎干细胞的分离培养与建系等方面做一概述。     

高效液相色谱法定性检测5种中兽药散剂中违规添加的氯霉素

建立了定性检测止痢散、白头翁散、苍术香连散、银翘散和清瘟败毒散五种中兽药散剂中违规添加的氯霉素的高效液相色谱法。根据《中国兽药典》2000年版二部规定的处方配制五种中药散剂，根据氯霉素禁用以前的临床治疗量和中药散剂的临床治疗量，在配制的中药散剂中定量加入氯霉素作为样品；用丙酮提取，高效液相色谱——二极管阵列检测器进行定性测定。试验表明，该方法快速、简便．可用于上述五种中兽药散剂中违规添加氯霉素的定性检测。     

关于我国新兽药研究开发的战略思考

以提高自主创新能力为主题，分析了我国兽药研究开发现状，提出了今后我国兽药行业及生产企业进行新兽药研究开发的战略目标设想、内容和建议。     

Evaluation of a Bacillus stearothermophilus tube test as a screening tool for anticoccidial residues in poultry

A Bacillus stearothermophilus var. calidolactis C953 tube test was evaluated for its ability in detecting the residue of selected anticoccidial drugs in poultry, specically sulfamethazine, furazolidone, and amprolium. Various concentrations of each drug were injected into chicken liver and kidney tissues and these tissues were tested to determine the drug detection limits for each drug. The detection limit was defined as the drug concentration at which 95% of the test results were interpreted as positive. The limits of detection in liver tissue were 0.35 µg/ml for furazolidone, 0.70 µg/ml for sulfamethazine and 7.80 µg/ml for amprolium. In kidney tissues, they were 0.30 µg/ml for furazolidone, 0.54 µg/ml for sulfamethazine, and 7.6 µg/ml for amprolium. It was concluded that this tube test could be used to screen for the residue of these three drugs in poultry.     

Isolation,Characterization, and Antimicrobial Drug Resistance Pattern of Escherichia coli Isolated from Japanese Quail and their Environment

Escherichia coli isolates were cultured from diseased Japanese quail and their environment. Of 31 E. coli isolates, 11 were cultured from heart blood of dead Japanese quail and 20 were from dead-in-shell embryos, fluff samples, and footbath and drinking water samples. All E. coli isolates were moderately positive on the Congo red binder test and 14 out of 31 isolates produced hemolysis on sheep blood agar. Twenty-seven isolates were grouped under serogroups O₄, O₉, O₃₈, O₄₂, and O₈₈, whereas 4 isolates could not be typed. Of the E. coli isolates cultured from Japanese quail infected with colibacillosis, 54.5% belonged to serogroup O₉ and the same serotype was predominant in the hatchery environment. All the E. coli isolates showed high resistance to multiple drugs with 100% resistance observed against ampicillin/cloxacillin, chloramphenicol, tetracycline, and cotrimoxazole. The highest sensitivity was observed against nitrofurantoin. This study shows that hatchery hygiene should be improved to control colibacillosis and reduce production losses. At the same time, indiscriminate use of antibiotics should be avoided as it increases the risk of development of drug-resistant strains of bacteria.     

细菌耐药颉颃剂的研究现状及应用

作者介绍了具有颉颃细菌耐药性作用的物质的研究应用进展情况，包括灭活酶抑制剂、药物渗透促进剂、外输泵抑制剂、细菌生物被膜抑制剂、抗菌药物增强剂、耐药质粒消除剂等。     

超抗原及其在兽医科学上的应用

超抗原以极低的浓度就能引起机体免疫细胞、细胞因子和抗体的巨大变化,引起机体一系列病理生理过程。鉴于超抗原的这种特性,医学上已成功将其用于癌症和病毒病的辅助治疗。在兽医科学上,超抗原有望在兽医病理学、兽医药理学、兽医临床治疗和兽医预防方面得到广泛的应用。