蛋氨酸羟基类似物(HMTBA)和酸化剂、抗生素对肠道病原菌的体外抑制对比试验

该研究采用平板法和试管法测定蛋氨酸羟基类似物(HMTBA)体外抑茵效果,并与常见有机酸,如乳酸(LA)、甲酸(FA)、柠檬酸(CA),以及二甲酸钾(KDF),广谱抗生素氯霉素(Chl)、诺氟沙星(Nor)进行比较.结果表明,HMTBA对6株供试茵的最低抑茵浓度(MIC)为0.1%～0.2%.与LA、CA、C.KDF、B.KDF相当,高于FA的0.05%～0.1%Chl对6株供试菌的最低抑茵浓度(MIC)为1.95～7.81 mg/kg,Nor对5株供试茵的最低抑菌浓度在0.391～0.781 mg/kg.而对鸡源沙门氏菌S1的MIC却是12.5 mg/kg,说明该菌已对Nor产生了耐药性.     

八种单一酸化剂的体外抑菌效果分析

为了评估不同酸化剂的体外抑菌效果,试验采用琼脂平板打孔法、试管二倍稀释法和平板培养法进行了八种单一酸化剂(甲酸、二甲酸钾、乳酸、苹果酸、酒石酸、富马酸、柠檬酸、磷酸)对3种标准菌和1株临床分离大肠杆菌的体外抑菌效果观察。结果表明:八种单一酸化剂对标准大肠杆菌、标准金色葡萄球菌、标准沙门氏杆菌及临床分离大肠杆菌均具有不同程度的抑菌作用,其中甲酸、富马酸和酒石酸的抑菌活性最强,乳酸、苹果酸和柠檬酸相对最弱。说明甲酸、富马酸和酒石酸的抑菌效果较好。     

有机酸对幼猪的有益效应

Partanen(2001)对46个断奶仔猪试验和23个肥育猪试验的分析发现:甲酸、延胡索酸、柠檬酸和二甲酸钾显著改善饲料效率,甲酸、二甲酸钾显著改善日采食量和日增重(表1)。有机酸对断奶仔猪的有益作用主要与胃肠道菌群的改变有关。有机酸对幼猪的有益效应     

酸化剂组成成分及抑菌效果的比较研究

为比较乳酸宝~(TM)与其他4种商品酸化剂在酸的组成及体外抑菌效果方面的差异,本试验利用高效液相色谱法测定酸化剂中有机酸的含量,分光光度法测定酸化剂中总磷含量,换算磷酸含量;并利用微量肉汤稀释法测定5种酸化剂对大肠杆菌CVCC 1555、金黄色葡萄球菌CVCC 1885和鼠伤寒沙门氏菌ATCC 14028这3种病原菌的最小抑菌浓度(MIC)。结果表明,乳酸宝~(TM)的总酸含量为67.54%,高于其他4种酸化剂。乳酸宝~(TM)对3种测试病原菌的MIC最小,其中对大肠杆菌和鼠伤寒沙门氏菌的MIC均为0.3%,对金黄色葡萄球菌的MIC为0.4%,其他4种酸化剂对3种病原菌的MIC为0.4%~0.6%,说明乳酸宝~(TM)体外抑菌效果最好。综上所述,5种酸化剂的组成成分和抑菌效果差异比较大,其中乳酸宝~(TM)的总酸含量和抑菌效果最好。     

不同单一酸化剂及复合酸化剂体外抑菌能力比较研究

为考察不同单一酸化剂以及复合酸在同等酸度的条件下抑菌能力的大小,试验采用菌落法,比较研究几种酸化剂及复合酸化剂在同等酸度条件下对大肠杆菌(ATCC25922)和金黄色葡萄球菌(ATCC6538)的抑菌能力。结果表明,单一酸化剂对革兰氏阳性菌金色葡萄球菌的抑菌能力依次为:甲酸苯甲酸富马酸磷酸、乳酸、柠檬酸;对革兰氏阴性菌大肠杆菌的抑菌能力依次为:富马酸柠檬酸磷酸、苯甲酸、甲酸、乳酸;且复合酸化剂的抑菌效果均优于单一酸化剂。     

二甲酸钾的合成

甲酸与碳酸钾在一定比例下,生成二甲酸钾白色结晶体.作者对二甲酸钾的合成方法进行了研究,产品收率达到48.1%,纯度97%以上,工艺简单,易于工业化生产.     

应用均匀设计法研究不同酸组合的抗菌效应

试验旨在研究不同酸配伍的抑菌效果,探索抑菌效果最佳的酸化剂配方。利用磷酸、甲酸、柠檬酸、乳酸等4种酸,用均匀设计的方法组成20种酸化剂配方,以体外抑菌试验研究各个酸化剂配方的抑菌效果并建立各酸在配方中的百分比与抑菌率的多元回归方程,优化求解得最佳抑菌效果酸化剂配方。结果表明,理论上要取得最佳抑菌效果的酸化剂配方为:磷酸35.5%,甲酸38.8%,柠檬酸6.7%,乳酸19%,此时配方的理论抑菌率为98.9%。     

仔猪粪便中乳酸菌的分离、鉴定及其抑菌特性的研究

从健康仔猪新鲜粪便中分离到3株乳酸菌,并对其进行了属和种的生化鉴定,结果显示,菌株La与Lt均为嗜酸乳杆菌(Lactobacillus acidophilus),Ls为乳酸乳杆菌(Lactobacillus lactis)。对分离的3株乳酸菌的代谢产物进行了体外抑菌试验研究,结果表明,3株乳酸菌的代谢产物对大肠杆菌、沙门氏菌和金黄色葡萄球菌都有较明显的抑制作用;对金黄色葡萄球菌的抑菌效果最好,沙门氏菌次之,对大肠杆菌的抑菌效果相对较弱。     

新型饲料添加剂二甲酸钾的合成和应用

二甲酸钾是一种能替代抗生素的促生长剂,绿色、安全。以甲酸与碳酸钾或甲酸与氢氧化钾为原料,合成了白色晶体二甲酸钾,讨论了物质的量比、反应温度、反应时间对产品收率的影响,产品收率少达83%,纯度98%以上。合成工艺简单,易进行工业生产。     

二甲酸钾对母猪体况和生长性能的影响

随着经济的发展和生活水平的日益提高,人们越来越重视和忧虑抗生素的残留和菌株的耐药性问题,消费者对安全绿色健康食品的呼声也愈来愈大,禁抗无抗是全球大势所趋。在目前讨论和研究的方案之中,二甲酸钾(KDF)引起动物营养学界和养猪业的广泛兴趣。欧洲各国对饲料用二甲酸钾的研究开发起源于20世纪90年代中期,1994年在挪威波斯格朗(Porsgrunn)Norsk Hydro的实验室因一次取萃石化用液体甲酸盐的意外,科学家Leif Hj?rnevik发现了沉淀中结晶的二甲酸钾,其在改善畜禽生长性能方面的作用相继被研究报道。2001年7月,欧盟批准了Norsk Hydro开发的Formi LHS(主要成分为二甲酸钾)作为第1个用于猪饲料抗生素促生长剂的代替品(Commission Reg.(EC) No.1334/2001),批准使用的应用范围局限于提高猪的生产性能。由此Formi开启了无抗新纪元,成为后抗生素时代一种可替代猪用生长促进剂。Formi作为无毒害、无残留无抗药性的环保型添加剂的作用越来越为人们所认知,被广大技术专家所推崇。国内外很多KDF的应用实验表明,二甲酸钾作为一种分子式简单的复合盐(具特殊结构的甲酸和甲酸钾),既继承了甲酸的抗菌防霉作用,又具备无腐蚀的缓释效应(单一酸化剂释放过快,在胃中即被全部吸收,无法在小肠部位发挥作用)。具有促进猪的生长,改善仔猪胃肠道消化环境,调节饲料的适口性,提高动物的采食量,有效抑制饲料中的霉菌等有害成分,保持饲料新鲜度和质量,延长饲料的保存期限等一系列作用,且酸化效果优于常用复合型酸化剂。KDF作为非抗生素促生长剂,主要针对断奶仔猪、生长育肥猪及哺乳母猪。文章只重点讨论了KDF饲喂母猪后对饲料采食量,养分消化率,母猪妊娠期至断奶期体况的影响。     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

A brief history of the prevention of infectious diseases by immunisations

Infectious diseases have always been a terrible scourge for humans. The appearance of these plagues, as they were called without distinction, was generally connected to various conditions: asters, climatic changes or religious reasons. The concept of contagious, and then infectious, diseases came slowly. Variolation, i.e. transmission of ‘virulent’ matter to induce a natural disease and the immunity against it, was brought from Constantinople to England by Lady Montague, in 1721. This ‘variolation’ technique was also often performed in veterinary medicine against diseases like sheep-pox or pleuropneumonia. As ‘vaccination’ is the term generally accepted for ‘immunisation’, variolation can be the word designating such a technique. The second period of the history of immunisation began, in 1880, with the studies of Pasteur and his collaborators. A great number of bacterial vaccines were developed: dead, live but attenuated or only parts of pathogens. The viruses were produced in animals, then in eggs and at last, in tissue cultures. Second generation vaccines appeared with genetic engineering: recombinant vaccines, vector vaccines, nucleic acids vaccines, and markers vaccines, among others. These novel technologies can permit the development of new ones and improve the quality of the vaccines already existing.