牛奶中土霉素、金霉素的残留分析方法研究

运用反相高效液相色谱-二极管阵列检测器建立了牛奶中土霉素、金霉素的残留分析方法。柱子采用Waters Nova-park C18柱(4μm,3·9mm i·d·×150mm),以体积比为68∶12∶20的0·01mol/L草酸溶液-乙腈-甲醇作为流动相,流速为1·0mL/min,柱温为30℃,检测波长为360nm,在上述色谱条件下,土霉素、金霉素在10min内得到了有效的分离和检测。建立的方法简便、快捷、线性范围宽,可用于牛奶中土霉素、金霉素的残留量分析。     

HPLC法测定鸡蛋中土霉素和金霉素的残留量

采用RP-HPLC方法同时测定了鸡蛋中土霉素和金霉素的残留量.用0.01 mol/L的乙二胺四乙酸二钠溶液和0.3%磷酸溶液为提取液,三氯乙酸(1 1)溶液为蛋白沉淀剂,离心后上清液经C18固相萃取柱净化、浓缩.色谱柱为Waters Symmetry ShieldTM RP18柱,250 mm×4.6 mm (i.d.),粒径5 μm;检测波长353 nm;以0.02 mol/L草酸∶乙腈∶ 0.01 mol/L磷酸二氢钠(45∶ 19∶ 36,V/V/V)为流动相.土霉素和金霉素标准曲线的线性范围分别为0.05～1.0 μg/mL和0.1～2.0 μg/mL.经过3种不同浓度回收率的测定,其回收率在50.6%～85.6%之间,RSD%小于8.60%(n＝5).     

UPLC和HPLC法检测猪肉中磺胺类药物残留的比较

比较了超高效液相色谱法与高效液相色谱法测定猪肉中磺胺类药物残留的结果。采用农牧发[2001]38号动物源食品中磺胺类药物残留的检测方法有关标准,将原高效液相色谱方法转换并优化为超高效液相色谱方法。高效液相色谱方法色谱柱为Waters Symmetry C18柱(4.6 mm×250 mm,5μm),流动相:乙腈-甲醇-水-乙酸(2∶2∶9∶0.2),流速:1 mL/min,进样量:50μL;超高效液相色谱方法色谱柱为Waters Acquity UPLC BEH RP18柱(2.1 mm×50 mm,1.7μm),流动相:乙腈-甲醇-水-乙酸(2∶2∶10∶0.2),流速:0.4 mL/min,进样量:5μL。结果表明超高效液相色谱方法能够替代高效液相色谱分析方法测定猪肉中磺胺类药物残留,既加快了分析速度,达到了样品分析的高通量,减少有机溶剂的使用,又得到更高的分析灵敏度。     

林可霉素-大观霉素复方混悬注射液中有效成分含量的HPLC法测定

建立了测定林可霉素-大观霉素复方油混悬注射液中盐酸林可霉素与盐酸大观霉素含量的高效液相色谱(HPLC)方法.采用C18色谱柱(4.6mm×250 mm,5 μm),检测林可霉素的流动相为0.05mol/L硼砂溶液(用850 mL/L磷酸调节pH至5.0)-甲醇-乙腈(60∶36∶4),检测波长为214 nm;检测大现霉...     

动物组织中四环素类抗生素残留的HPLC检测研究

本试验建立了动物组织中四环素类药物残留的高效液相色谱测定方法。试验分别采用50 mL/L高氯酸、Mcllvaine缓冲液为样品提取液;乙腈/磷酸二氢钠、甲醇乙腈0.01mol/L草酸(1.5 1.5 2.0,pH 2.0)为流动;流速1.0 mL/min,组合测定。结果显示,50 mL/L高氯酸为样品提取液,流动相甲乙腈0.01 mol/L草酸,检测灵敏度较高在此色谱条件下,土霉素、四环素、金霉素的最低检测限为100μg/kg,在100μg/kg~1 000g/kg浓度范围内,标准添加回收率为74.3%~97.1%,变异系数为0.43%~9.54%。本方法适用于四环素类抗生素残留的确证性定量分析。     

固相萃取-高效液相色谱法测定环境水体中四种四环素类抗生素及其稳定性研究

为了利用固相萃取-高效液相色谱法同时检测环境水体中土霉素、四环素、金霉素和强力霉素,采用PEP固相萃取柱净化富集,以0.01 mol/L草酸∶乙腈∶甲醇=7∶2∶1为流动相,检测波长为355 nm。结果表明:标准曲线在0.10～10.00 mg/L具有良好的线性关系(R~2 0.999),检出限为0.2～0.5μg/L,定量限为0.5～2.0μg/L,方法回收率为80.32%～104.90%,相对标准偏差为2.54%～7.85%。说明该方法操作简单、分析快速、重现性好,可用于环境水体中四环素类抗生素的测定。四环素类抗生素的稳定性研究显示,升温、光照可促进四环素类抗生素的分解,而环境中有机物的影响则呈现两面性。     

牛奶中氯霉素残留的气相色谱测定法研究

研究了牛奶中氯霉素残留的气相色谱法测定方法.用乙酸乙酯提取,蒸干,4%氯化钠溶液溶解残渣,正己烷脱脂后过C18固相萃取柱净化,甲醇洗脱,硅烷化试剂50 ℃衍生30 min后测定.该方法在添加浓度为0.1～1.0 ng/ mL时,氯霉素回收率为71.2%～87.8%,批间变异系数为14.3%～19.7%,检测限为0.04 μg/L ,定量限为0.1 μg/L ,达到了欧盟的规定要求,适合牛奶中氯霉素残留分析.     

链霉素在牛奶中残留的微生物学检测方法

建立了链霉素在牛奶中残留的微生物学检测方法.样品用10%(W/V)三氯乙酸提取,通过冷冻离心使牛奶中残留的链霉素得到分离,再用枯草芽孢杆菌作为检定菌进行含量测定.结果显示,链霉素在0.10～3. 20 μg/mL的浓度范围内具有良好线性关系(r=0.998 1),牛奶中3种添加浓度0.20、0.80、1.60 μg/g的平均回收率为97.6%(n=9),RSD分别为1.6 %、3.7 %、1.2 %(n=3).     

高效液相色谱法测定抗病毒颗粒中黄芩苷的含量

采用高效液相色谱法测定抗病毒颗粒中黄芩苷的含量.用C18色谱柱(150 mm×3.9 mm,5 μm),以甲醇-磷酸二氢钠缓冲液(0.2 mol/L,pH 2.7)(42∶58,V/V)为流动相,流速为1 mL*min-1,检测波长为275 nm.黄芩苷在0.02～0.1 mg/mL的浓度范围内,峰面积与浓度呈良好线性关系,r=0.999 9,回收率为98.7%.     

牛奶中土霉素残留检测方法改进及临床消除规律探究

试验对牛奶中的土霉素残留检测方法进行了改进,并采用改进后的方法对牛奶中土霉素的临床消除情况进行了探究。样品前处理过程中,选取0.1mol/LNa₂EDTA-Mcllvaine缓冲溶液提取牛奶中的土霉素,正己烷除脂及HLB固相萃取柱净化浓缩。釆用Symmetry Shield RPC18(250mm×4.6mm,5μm)反相色谱柱,以乙腈和0.048%的磷酸溶液(pH2.5)为流动相,采用梯度洗脱的方式对样品进行分析。方法改进后,土霉素的出峰时间为6.5min,峰形尖锐,与样品中的杂质峰分离良好。土霉素标准溶液在5~2000μg/kg范围内线性关系良好,标准曲线R²=0.9999;牛奶中土霉素在10、20、100μg/kg3组浓度的加标回收率分别为87.9%、90.5%和87.8%,批内变异系数范围为2.2%~5.8%,批间变异系数范围为4.0%~5.1%。土霉素在牛奶中的检出限为5μg/kg,定量限为10μg/kg,适用于研究土霉素在牛奶中的残留消除规律。选取了29头产后患有子宫内膜炎的奶牛,分成4个不同剂量组(2、3、4和5g),通过子宫内灌注土霉素的方式进行治疗,然后采用优化后的方法检测牛奶中残留的土霉素。结果发现,4g及以下剂量组给药72h后,牛奶中的土霉素可以消除至残留限量以下;而当给药剂量达到5g时,72h后牛奶中的土霉素未消除至残留限量以下,因此不建议采用5g及以上剂量灌注病牛子宫。     

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.