维生素E对秦川牛冷冻精液的抗氧化保护作用

本试验旨在研究维生素E对秦川牛细管冷冻精液品质和精浆中抗氧化酶活性的影响.在稀释液中分别添加0.00、0.02、0.04、0.06、0.08、0.10 mg·mL~(-1)的维生素E,将细管冻精解冻(37.5℃,30 s)后用伟力精子分析系统分析精子活力和精子顶体完整率等标准参数,并用相关试剂盒测定精浆中的超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH)、谷胱甘肽还原酶(GR)和过氧化氢酶(CAT)的活性.结果表明:当维生素E添加量为0.04mg·mL~(-1)时,精子活力与对照组相比差异显著(P<0.05),SOD、GSH、CAT 3种酶活性与对照组相比差异显著(P<0.05).当维生素E的添加量为0.06 mg·mL~(-1)时,冷冻-解冻后精子活力显著高于对照组(P<0.05),顶体完整率极显著高于对照组(P<0.01);GR和CAT酶活性与对照组相比均差异显著(P<0.05).当维生素E的添加量为0.08 mg·mL~(-1)时,精子活力、活率及顶体完整率与对照组相比差异显著(P<0.05),GSH与对照相组比差异极显著(P<0.01),GR及CAT与对照组相比差异显著(P<0.05).在冷冻精液稀释液中添加维生素E可以有效提高冷冻-解冻后秦川牛精液品质及精浆中SOD、CAT、GSH、GR酶的活性,稀释液中维生素E的适宜添加量为0.04～0.08 mg·mL~(-1).     

Utilization of stereoisomers from alpha‐tocopherol in livestock animals

Alpha‐tocopherol derived from natural source is a single stereoisomer (i.e. RRR‐α‐tocopherol), whereas synthetic α‐tocopherol consists of a mixture of eight stereoisomers, including RRR‐, RRS‐, RSR‐, RSS‐α‐tocopherol (the 2R isomers, R configuration at positions 2′ of the phytyl tail) and SRR‐, SSR‐, SRS‐ and SSS‐α‐tocopherol (the 2S isomers, S configuration at positions 2′ of the phytyl tail). R and S are assigned by the sequence‐rule procedure, i.e. the priorities of the substituents decrease in clockwise direction or anti‐clockwise direction at each chiral centre. Not all these stereoisomers are equally bio‐available, which can be explained by the differences in the rate of degradation, transportation and retention. Humans and livestock animals can only utilize the 2R forms, while the 2S forms have very low bio‐availability or basically are not bio‐available. The utilization of 2R forms differs between different animal species. For humans and livestock animals, RRR‐α‐tocopherol has the highest bio‐availability compared with other stereoisomers, while other 2R forms have lower bio‐availability compared with RRR‐α‐tocopherol. The relative bio‐availability of RRR‐ and all‐rac‐α‐tocopherol is related to animal species, ages of animals and assessment criteria. In general, recent literature studies have demonstrated that the relative bioavailability of RRR‐ and all‐rac‐α‐tocopherol is 2:1, differing from the commonly used conversion factor of 1.36:1. The latter was based on rat‐resorption‐gestation test. Most recent studies have shown that this conversion factor of 1.36:1 is not applicable to livestock animals and based on other metabolic functions. When IU is required to express vitamin E activity, new conversion factors need to be defined for livestock animals. Quantitative determination of bio‐availability of the individual α‐tocopherol stereoisomers will give a more detailed picture of the bioavailability of natural and synthetic vitamin E forms.     

硝唑尼特混悬液对鸡柔嫩艾美尔球虫病治疗效果研究

采用人工接种柔嫩艾美尔球虫孢子化卵囊的方法复制鸡球虫病模型,检测发病率、死亡率、存活率、增重量等指标,研究硝唑尼特混悬液对鸡球虫病的临床治疗效果.结果显示,高、中、低剂量的硝唑尼特抗球虫指数分别为163.6、168.3、137.9;硝唑尼特混悬液与癸氧喹酯对照组相比差异显著(P＜0.05),与妥曲珠利对照组相比差异不显著(P＞0.05);硝唑尼特混悬液高剂量组和中剂量组差异不显著(P＞0.05),抗球虫指数为中效,低剂量组的抗球虫指数为低效.试验证明,硝唑尼特混悬液对鸡柔嫩艾美耳球虫病具有一定的治疗效果,有望开发为新的抗球虫药物.     

鸡致病性大肠杆菌I型菌毛交叉保护性研究及其结构基因 FimA 的序列分析

从山东省各地分离到107株鸡致病性大肠杆菌，选择了其中2株高致病性大肠杆菌，血清型分别为O78和OM，经增菌培养后提取菌毛制备为单价菌毛油乳苗，分别接种于1日龄和14日龄雏鸡，于4周龄攻毒。结果二者之间有一定的交叉保护作用。根据Genbank收录的人源大肠杆菌I型菌毛FimA基因和P型菌毛papA基因序列，分别设计了2对引物。通过PCR对上述2株大肠杆菌进行扩增，结果只有FimA的一对引物扩增出相应的条带，经测序证明为FimA基因。papA基因的引物未扩出任何条带，证明这2株大肠杆菌表达I型菌毛。通过对2株大肠杆菌结构基因FimA进行分析，发现二者具有高度的同源性。本研究的目的是探讨菌毛亚单位之间的交叉保护性与其菌毛的结构基因之间是否存在相关性。     

TCDCA对IL-1β刺激下AA大鼠成纤维样滑膜细胞中PGE2分泌的影响

[目的] 进一步探讨牛磺鹅去氧胆酸（taurochenodeoxycholic acid,TCDCA）在抗炎免疫方面的潜在调节作用。[方法] 以AA大鼠成纤维样滑膜细胞作为研究对象,采用ELISA方法检测TCDCA和IL-1β作用下AA大鼠成纤维样滑膜细胞上清液中PGE₂的含量,分析TCDCA对IL-1β刺激下AA大鼠成纤维样滑膜细胞中PGE₂分泌情况的影响。[结果] TCDCA能够对IL-1β刺激下AA大鼠纤维样滑膜细胞PGE₂的分泌产生下调作用（P<0.05）。[结论] TCDCA对IL-1β刺激下AA大鼠成纤维样滑膜细胞中PGE₂的分泌具有抑制作用,为TCDCA在兽医临床应用提供依据。     

硒与维生素E对鸡马杜霉素急性中毒的保护作用

在实验条件下用7mg/kg bw.剂量的马杜霉不诱发鸡急性中毒，处理组鸡在给马杜霉素前给予硒（0.2mg/kg bw.剂量，内服）－维生素E（每kg饲料含200mg)7d，在给马杜霉素后给予硒（0.2mg/kg bw.剂量，内服）－维生素E（200mg/kg bw.剂量，肌注）4d，中毒组在给马杜霉素前后不给任何硒和维生素E，对照组既不给马杜霉素，也不给硒与维生素E。结果是：处理组鸡的死亡率显著低于中毒组（P＜0.05），且病鸡恢复比中毒组快。处理组的肝脏、心肌、骨骼肌的出血与变性比中毒组轻，但处理组与中毒组的肾脏的出血与变性的程度相似；处理组的血清GOT值、肝脏的脂质过氧化物的含量、肝脏过氧化氢酶的性均显著低于中毒组；但处理组的血清CK值与中毒组相比无显著性差异。结果表明硒与维生素E对鸡马杜霉素急性中毒有较好的保护作用。     

Fecal carriage of multi-drug resistant and extended spectrum β-lactamases producing E. coli in household pigeons,Bangladesh

Antibiotic resistance and ESBL constitute a risk to human and animal health. Birds residing close to humans could mirror the spectrum of human associated antibiotic resistance. Household pigeons were screened in Bangladesh to shed light on human associated, as well as, environmental antibiotic resistance. Escherichia coli from pigeons (n = 150) were tested against 11 antibiotics. 89% E. coli isolates were resistant to one or more critically important human antibiotics like ampicillin, cefadroxil, mecillinam, ciprofloxacin, gentamicin and tigecycline. No carbapenamase-producers were detected and the lower ESBL prevalence (5%) in pigeons. ESBL-producing E. coli isolates had bla_CTX-M-15 genes. Pigeons shared some bacterial clones and had bird associated sequence types like E. coli ST1408. Fecal carriage of bacteria resistance of critically important human antibiotics, together with examples of shared genotypes among pigeons, indicate the human-birds and bird to bird transmissions are important in the epidemiology of antibiotic resistance.     

Ultrastructure of Colonic Epithelial Cells in Vitamin E and Selenium Deficient Pigs

Pigs deficient in vitamin E and selenium had a decreased contrast of the intracellular membranes compared with pigs supplemented with vitamin E and selenium. Other common changes in the deficient animals included a reduced number of microvilli, with a short and irregular appearance, numerous swollen mitochondria with empty spaces and intercellular oedema. It is suggested that these morphological changes are attributed to the insufficient supply of vitamin E and selenium, though it is not excluded that particular intestinal factors may participate in the development of the lesions.     

基于PRO/E的水轮机转轮三维造型

利用Pro／E和AutoCAD的良好接口直接调入已有的混流式转轮二维木模图的叶片截面图形，对于上冠和下环附近叶片延展时的不确定性和容易出现的畸变问题采用了虚拟上冠和确定叶片尖点的方法，进行了转轮的三维造型。造型完成后，可直接利用Pro／E下的分析功能得出叶片真实厚度、重心位置、体积、表面积、转轮开口、转轮质量等相关数据。实现了转轮三维几何设计与流体动力学设计的一体化．为转轮内流动CFD分析、性能预测和CAM奠定了可靠的基础。