超高效液相色谱—串联质谱法检测鸡组织中黏杆菌素残留

将鸡组织样品经酸性乙腈溶液提取,正己烷去脂后C18固相萃取柱净化,样品浓缩后在XevoTM TQ-S串联四极杆质谱仪多反映监测(MRM)下测定.黏杆菌素标准曲线在10 μg/kg到1000 μg/kg浓度范围内线性良好(r＞0.997).在0.02μg/g、0.10 μg/g、1.00 μg/g添加水平下,黏杆菌素在鸡组织(肾脏、肝脏、肌肉和脑)中添加回收率在83.43％～98.15％之间,日内和日间变异系数(RSD)均小于10％;黏杆菌素在鸡组织中的定量限为20 μg/kg,最低检测限为10 μg/kg.结果表明,建立了一种灵敏、可靠的检查鸡组织中黏杆菌素药物残留的超高效液相色谱-串联质谱分析方法.     

UPLC-MS/MS快速测定鸡肉中金刚烷胺和氟喹诺酮类药物残留

建立了鸡肉中金刚烷胺和八种氟喹诺酮类药物的UPLC-MS/MS测定方法.鸡肉样品经QuEChERS萃取剂提取,QuEChERS净化剂净化后,经氮气流吹干浓缩后进行测定,稳定同位素内标法定量.结果表明,金刚烷胺的测定线性范围为0.2～10.0 μg/kg.在0.2、1.0、10.0 μg/kg三个浓度的回收率为80％～120％;氟喹诺酮类药物的测定线性范围为2～ 100 μg/kg,在2、10、100μg/kg三个浓度的回收率为80％～120％,批内、批间精密度小于20％.该方法简便、快速、灵敏,适用于鸡肉中金刚烷胺和氟喹诺酮类药物残留的大批量筛选和定量测定.     

牛肝中氯舒隆残留检测高效液相色谱-串联质谱法研究

研究了采用固相萃取净化,高效液相色谱-串联质谱(HPLC-MS/MS)法测定牛肝中氯舒隆残留量的方法.样品用乙腈提取,HLB固相萃取小柱净化后,HPLC-MS/MS方法检测.离子源采用电喷雾负离子方式(ESI-),多反应监测(MRM)模式进行采集,外标法定量.结果表明:方法检测限为2 μg/kg,定量限为5 μg/kg.在5、20、100 μg/kg三个添加浓度范围内,方法的平均回收率为86.6%～93.5%;方法RSD≤6.8%.     

气相色谱-质谱法快速测定猪尿中地西泮

建立了猪尿中地西泮的气相色谱-质谱(GC/MS)检测方法.样品经C18固相萃取柱净化后进行气相色谱-质谱测定.结果表明,方法定量限为0.5 μg/L,线性范围为10～500 μg/L.在三个添加浓度2、4、6 μg/L水平上,地西泮的平均回收率为 70%～120%,批内相对标准偏差< 20%、批间相对标准偏差< 12%.     

超高效液相色谱-串联质谱法检测动物源食品中氯霉素类药物及其代谢物残留

建立了动物源食品中氯霉素、甲砜霉素、氟苯尼考及氟苯尼考胺残留检测的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法.样品在碱性条件下用乙酸乙酯提取后,再用正己烷去除脂肪,浓缩后用BEH C18(50 mm×2.1 mm,1.7 μm)色谱柱分离,以乙腈和水为流动相进行梯度洗脱,流速为0.3 mL/min,多反应监测(MRM)模式检测.结果表明:四种药物在2～500 μg/L的系列浓度范围内均呈良好线性关系,相关系数r均大于0.990.样品中氯霉素的检测限为0.1 μg/kg,定量限为0.2 μg/kg;甲砜霉素、氟苯尼考和氟苯尼考胺的检测限为0.5 μg/kg,定量限为1 μg/kg.本方法氯霉素在0.2～1 μg/kg的添加浓度范围内,甲砜霉素、氟苯尼考及氟苯尼考胺在1～50 μg/kg的添加浓度范围内平均回收率均为70%～120%,相对标准偏差(RSD)均小于20%.该方法具有简便快捷、灵敏度高、定性准确等特点.     

高效液相色谱法测定动物性食品中地昔尼尔残留量

本试验建立了羊肉和牛肉中地昔尼尔残留高效液相色谱方法,样品经乙腈提取,正己烷脱脂,HLB固相萃取柱净化,高效液相色谱分离,270 nm波长下紫外测定。结果表明,地昔尼尔在20～1000 μg/L浓度范围内线性良好,相关系数大于0.99;在100～1000 μg/kg的添加回收试验中,平均回收率为81.8%～93.4%,批内变异系数（n=5）小于11.9%,批间变异系数（n=3）小于9.4%。地昔尼尔在羊肉和牛肉中的检测限分别为 30.0和28.0 μg/kg,定量限分别为100.0和93.1 μg/kg,该方法简单、灵敏和准确,可用于动物性食品中地昔尼尔的残留检测分析。     

三种方法检测克伦特罗确保猪肉食用安全

本篇文章主要提出用三种方法:试剂条法、ELISA法、液相串联质谱法做为检测克伦特罗的重要手段。我们利用6个尿样和6个组织样品分别做了添加回收。用试剂条法检测6份添加浓度分别是3μg/L、6μg/L猪尿样品,其结果显示是阳性。用ELISA法对添加浓度分别是100ng/kg、300ng/kg的6份组织样品进行检测,回收率是98.9%～99.4%,液相串联质谱法检测猪肉组织中添加浓度为50ng/kg,100ng/kg,300ng/kg,500ng/kg的组织样品,检测回收率为99.4%～103.4%,验证结果证明三种方法均能满足实际检测的需要。     

高效液相色谱法测定鸡蛋中氟喹诺酮类药物残留量前处理方法的优化

建立了鸡蛋中环丙沙星、达氟沙星、恩诺沙星和沙拉沙星4种氟喹诺酮类药物残留测定的超高效液相色谱方法。样品经磷酸盐缓冲液提取后,用正己烷脱脂,C18固相萃取柱净化,反相高效液相色谱分离,荧光检测器测定。本方法的检测限为环丙沙星、恩诺沙星和沙拉沙星5 μg/kg,达氟沙星1 μg/kg。环丙沙星、恩诺沙星和沙拉沙星在2~200 ng/mL、达氟沙星在0.4～40 ng/mL范围内呈线性相关,相关系数r大于0.9999。在空白鸡蛋中添加环丙沙星、恩诺沙星和沙拉沙星5~50 μg/kg、达氟沙星1～10 μg/kg,4种氟喹诺酮类药物的平均回收率为82.2～101.3％,批内变异系数0.8～5.9％之间(n＝6),批间变异系数在1.0～6.6％之间(n＝4)。结果表明,该法灵敏、准确、特异性强,适用于鸡蛋中氟喹诺酮类药物残留的测定。     

液质联用法测定饲料中14种抗菌药物的研究

建立了液相色谱-串联质谱(LC-MS/MS)联用技术同时测定饲料中硝基咪唑类、硝基呋喃类、喹噁啉类14种抗菌药物的分析方法.样品通过乙腈-水(60:40,V/V)溶液提取,HLB固相萃取柱净化后上机测定.在正离子模式下通过两对离子对进行定性定量分析.结果表明,14种药物在2～100 ng/mL范围内线性关系良好,相关系数均大于0.99,空白饲料在三个添加浓度下的回收率为46.5％～114.4％,批内、批间相对标准偏差均＜20％,检测限为20 μg/kg.该方法适用于饲料中14种抗菌药物的同时测定.     

鸡组织中氯霉素残留的气相色谱-微电子捕获检测方法研究

建立了鸡肌肉和鸡肝脏组织中氯霉素残留的气相色谱-微电子捕获检测方法。用乙酸乙酯提取样品中的药物，正己烷脱脂，乙酸乙酯液-液分配，氮气吹干后，用Sylon BFT衍生化，进配有微电子捕获检测器（μECD）的气相色谱仪测定，外标法定量。鸡肌肉组织在0．1、0．5、1．0μg／kg三个添加水平，平均回收率为90．2％～94．3％，日内变异系数在4．5％-11．6％之间，日间变异系数在7．8％～14．3％之间，检测限0．05μg/kg，定量限0．10μg/kg。鸡肝脏组织在0．2、0．5、1．0μg/kg三个添加水平，平均回收率为82．9％～90．8％，日内变异系数在7．0％～11．2％之间。日间变异系数在7．9％～14．5％之间，检测限0．10μg/kg，定量限0．20μg/kg。     

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.     

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.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

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.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein