Effect of Enterococcus faecium AL41 and Thymus vulgaris essential oil on small intestine integrity and antioxidative status of laying hens

We investigated the effect of Enterococcus faecium on phagocytic activity, antioxidative status in vivo and the effect of E. faecium and 0.4% concentration of Thymus vulgaris essential oil (EO) on the duodenal tissue integrity in vitro in laying hens. The birds were fed the same standard diets and were divided into four groups. E. faecium was added to the drinking water for the second and fourth groups. EO was added to special chambers for measuring trans-epithelial electrical resistance (TEER) for the third and fourth groups only. TEER was lower in groups where EO was added, but in the group with E. faecium TEER was not changed significantly. Our results show that EO at 0.4% concentration may negatively affect intestine integrity, and the probiotic strain E. faecium AL41 is able to eliminate this effect and can strengthen non-specific immunity. To confirm our findings further histopathological investigations of intestinal tissue are needed.     

动物大肠杆菌耐药性的变化趋势

本试验对50年代至90年代初分离保存的50株大肠杆菌进行了药物敏感性测定。结果表明，随着时间的推移，菌株对15种抗菌药物的耐性呈现不同程度的上升趋势，50年代的大肠杆菌分离株对15种抗菌药物均敏感，60年代的分离株对链霉素、四环素产生耐药，70年代对氨苄西林、氯霉素、磺胺甲基异唑、四环素、链霉素、甲氧苄胺嘧啶6种抗生素产生耐药，80年代至90年代初对阿莫西林／奥格门丁、庆大霉素、卡那霉素、萘啶酸、头孢噻吩、氨苄西林、氯霉素、磺胺甲基异唑、四环素、链霉素、甲氧苄胺嘧啶11种抗生素产生耐药，菌株的多重耐药性呈上升趋势。     

解决聚丙烯芯钢丝绳生产过程中钢丝“塌陷”（或间隙不均）及绳径超差问题

本文从生产制造角度来分析解决聚丙烯芯钢丝绳生产过程中易出现的钢丝塌陷、钢丝间隙不均及绳径超差等问题。与天然纤维芯相比,聚丙烯芯是一种合成纤维芯,除具有质轻、弹性好、不怕霉蛀等特性外,同时还具有较好的抗挤压性,因此,生产过程中,对聚丙烯芯直径公差的控制比对天然纤维芯直径公差的控制更为严格,如聚丙烯芯直径选择不当,易会出现股中钢丝塌陷(或钢丝间隙不均)、绳径超差等问题。笔者结合生产实际情况,从控制聚丙烯绳芯(股芯)直径公差入手,找出聚丙烯芯直径的计算值与其实测值之间合适的比例范围,对正确选择聚丙烯绳芯(股芯)直径大小,满足钢丝绳生产工艺要求,优化工艺参数,提高钢丝绳结构的稳定性和机台生产作业率有着重要的作用。     

禾草对禾顶囊壳玉米变种的抗病性研究

利用人工接菌方法测定了10种草坪禾草,包括多年生黑麦草、高羊茅、紫羊茅、中华结缕草、硬羊茅、草地早熟禾、加拿大早熟禾、匍匐剪股颖、细弱剪股颖、狗牙根;13种禾本科牧草,包括一年生黑麦草、鸭茅、碱茅、扁穗冰草、沙生冰草、披碱草、老芒麦、杂交小米草、猫尾草、弯叶画眉草、无芒雀麦、百喜草、苏丹草;以及4种禾本科作物,包括燕麦、甜高粱、小麦、玉米对禾顶囊壳玉米变种的抗病性。结果表明,多数供试禾草对其具有免疫能力,多年生黑麦草、一年生黑麦草、草地早熟禾、小麦高度抗侵染;无芒雀麦和玉米具有中等程度的抗侵染能力,但抗侵入能力较差;高粱属的苏丹草和甜高粱中度感病,属于中感作物。多年生黑麦草和草地早熟禾品种间存在着抗病性差异,有免疫品种和高抗品种。     

兽用喹诺酮类药物发展动态

综述了兽用喹诺酮类药物—包括国内外已上市的、尚在开发中的以及人用药可转化为兽用药三个部分的品种,并对在我国尚未上市的兽用喹诺酮类药物的药理作用及用途作了简介。     

结缕草种子预处理反应与耐藏性的探讨

为了提高结缕草种子发芽力和耐藏性,根据结缕草种子的特性,对不同贮藏期的种子,进行多种物理的和化学的预处理措施试验。     

Oral glucose leads to a differential response in glucose,insulin, and GLP-1 in lean versus obese cats

The response to oral glucose was examined in 10 obese and 9 lean age-matched, neutered cats. In all cats, oral administration of 2 g/kg glucose was followed by a prompt increase in glucose, insulin, and glucagon-like peptide (GLP)-1. There were significant differences between lean and obese cats in the areas under the curve for glucose, insulin, and GLP-1. However, the responses were variable, and a clear distinction between individual lean and obese cats was not possible. Therefore, this test cannot be recommended as a routine test to examine insulin resistance in individual cats as it is used in people. A further disadvantage for routine use is also the fact that this test requires gastric tubing for the correct administration of the glucose and associated tranquilization to minimize stress and that it was associated with development of diarrhea in 25% of the cats. GLP-1 concentrations were much lower in obese than lean cats. The low GLP-1 concentrations in obese cats might indicate a contribution of GLP-1 to the lower insulin sensitivity of obese cats, but this hypothesis needs to be further investigated.     

The in vitro diagnosis of anthelmintic resistance in cyathostomins

Cyathostomins are the primary parasitic pathogens of equids. For over 40 years, these nematodes have been controlled using broad spectrum anthelmintics. Three classes of anthelmintic are currently available for this use but, unfortunately, resistance to each of these has now been recorded in cyathostomin populations. As part of an optimal strategy to control cyathostomin infections in the field, it will be important to identify drug-resistant worms at as early a stage as possible. This objective needs to be supported by methodologies that will allow the accurate comparison of anthelmintic resistance in different nematode populations. At present, the faecal egg count reduction test is considered the most suitable method for initial screening for anthelmintic resistance in equine nematode populations. However, in its current state, this test lacks sensitivity. It is also costly and time-consuming to perform. Laboratory-based techniques, such as the egg hatch assay, larval development assay, larval migration inhibition assay and the larval feeding inhibition assay offer alternative options for assessing anthelmintic resistance in nematode populations. All of these tests have been investigated for their utility in measuring drug resistance in sheep nematode populations and some have proven useful. The egg hatch assay, larval development assay and larval migration inhibition assay have been investigated for use in measuring levels of drug resistance in equine nematode populations. However, at best, the results obtained thus far indicate that these tests require further refinement.     

H5N1亚型禽流感病毒A/Guangxi/1/2005株抗药机制的研究

为研究H5N1亚型禽流感病毒(AIV)的抗药机制,本研究选取Clade2.3.4亚群中一株对金刚烷胺敏感的人源AIV A/Guangxi/1/2005(H5N1)(S-GX05),用抗流感病毒药物金刚烷胺对其进行定向诱导,筛选出一株抗药性病毒株,命名为R-A/Guangxi/1/2005(R-GX05)。通过全基因测序并与S-GX05全基因序列进行对比,结果显示S-GX05只在其M2蛋白中有一个氨基酸位点发生突变,即A30P;抗药性鉴定这两株病毒的半数药物抑制浓度(IC50)分别为0.9μM和48.9μM,表明R-GX05对金刚烷胺表现出一定程度的抗性。动物实验证实,这两株病毒对BALB/c小鼠的致病性基本一致,均表现出高致病性,其MLD50分别为4.7 log10 EID50和5.0 log10 EID50,两株病毒在小鼠体内各组织脏器中的分布及增殖能力也基本相同。这些结果表明,S-GX05在药物压力下产生抗药性后,并未引起其它生物学特性的改变。A30P的发现为进一步从分子水平上研究H5N1亚型AIV的抗药机制及新型抗流感新药的研发奠定了基础。