超高效液相色谱-串联质谱法测定牛羊可食性组织中巴氯芬残留量

建立超高效液相色谱-串联质谱测定牛羊可食性组织中巴氯芬残留量的分析方法。取均质后的动物组织经80%(V/V)乙腈甲酸溶液提取,加入无水硫酸镁和氯化钠进行脱水和盐析,高速离心分层后合并提取液,取适量乙腈层溶液经prime HLB直过式固相萃取柱净化后,以40℃氮气吹干。残渣以15%乙腈甲酸溶液复溶后以反相C₁₈为固定相,0.1%甲酸与0.1%甲酸乙腈为流动相,采用梯度洗脱程序进行分离,以串联质谱进行同位素内标法定性定量分析。巴氯芬在0.5～50μg/kg范围内线性关系良好(r=0.9994),方法的最低检出限为0.25μg/kg,最低定量限为0.50μg/kg,添加回收率在89.09%～109.52%内,批内批间变异系数(CV)小于10%。该方法具有较好的准确度与精密度,适用于牛羊可食性组织中巴氯芬残留量的测定。     

超高效液相色谱-串联质谱法测定鸡蛋中沙拉沙星残留的研究

建立了鸡蛋中沙拉沙星残留检测的液相色谱-串联质谱法。样品经1 mol/L磷酸和乙腈提取后,饱和正己烷除脂净化,以0.1%甲酸溶液和乙腈为流动相,液相色谱-串联质谱法测定,内标法定量。试验结果表明：沙拉沙星在1～25 ng/mL浓度范围内线性关系良好,相关系数r大于0.999。沙拉沙星在鸡全蛋及其蛋清、蛋黄中的检测限均为0.5μg/kg,定量限为1μg/kg。沙拉沙星在1、10、20μg/kg浓度添加水平内的平均回收率范围为97.0%～105.4%,批内、批间相对标准偏差在1.3%～10.3%范围之间。本方法适用于鸡全蛋及其蛋清、蛋黄中沙拉沙星残留量的测定。     

高效液相色谱-串联质谱法检测鸡蛋和鸡组织中恩诺沙星、环丙沙星残留的研究

为建立一种高效液相色谱-串联质谱法检测鸡蛋和鸡组织(肝脏、肾脏、肌肉、脂肪)中恩诺沙星、环丙沙星的残留,鸡蛋和鸡组织(肝脏、肾脏、肌肉、脂肪)经酸化乙腈提取,正己烷除脂净化,以0.1%甲酸水溶液和乙腈为流动相进行梯度洗脱,同位素内标法定量。结果显示:恩诺沙星、环丙沙星均在线性范围内呈现良好线性关系,相关系数(R2)均大于0.99;恩诺沙星、环丙沙星在组织中的检测限为1μg/kg,定量限为5μg/kg;两种药物的平均回收率范围为75.5%～106%,批内、批间变异系数均小于11.2%。研究表明,该方法样品前处理简单,灵敏度高,适用同时检测鸡组织(肝脏、肾脏、肌肉、脂肪)和鸡蛋中恩诺沙星、环丙沙星残留。     

高效液相色谱法测定动物肺脏中替米考星残留量

建立了动物(牛、猪、鸡)肺脏中替米考星残留量的高效液相色谱检测方法。样品用乙腈提取,C18固相萃取柱净化,紫外检测器290nm测定。空白动物肺脏中添加0.04、0.1、1.0、10.0mg/kg浓度的替米考星,方法的平均回收率在76.8%～94.1%之间,变异系数在2.7%～8.6%之间,检测限为0.01mg/kg,定量限为0.04mg/kg。该方法可以用于动物肺脏中替米考星残留量的测定。     

猪肉及组织中β-受体激动剂UPLC-MS/M检测方法研究

超高效液相色谱串联质谱法(UPLC-MS/MS)检测猪肉中克伦特罗、莱克多巴胺、沙丁胺醇3种β-受体激动剂残留方法.选用盐酸葡萄糖醛苷酶/芳基硫酸酯酶水解,混合型阳离子交换固相萃取净化,以0.1%甲酸水溶液-0.1%甲酸乙腈溶液-甲醇为流动相,超高效液相色谱串联质谱法检测,在1.0、5.0、10μg/kg浓度添加水平,空白肌肉组织中3种药物添加平均回收率范围84~95%,标准偏差3.6~8.1%.该方法检测限为0.1μg/kg,定量限为0.3μg/kg,具有准确敏感特性.     

鸡肉组织中氯丙嗪残留的HPLC-MS/MS检测方法的建立

本研究建立了鸡肉组织中氯丙嗪残留检测的高效液相色谱-串联质谱(HPLC-MS/MS)定量确证方法。建立的方法所用样品用酸化乙腈和乙腈饱和正己烷提取后,采用C18柱色谱分离,正离子扫描模式,分别以乙腈和5 mmol/L乙酸铵水溶液(含0.1%甲酸)、乙腈和水为流动相,梯度洗脱,电喷雾电离,多反应监测模式检测,内标法定量。该方法检测限为0.008μg/kg,定量限为0.025μg/kg,在0.025~2.5μg/kg的添加范围内,回收率为71.5%~86.7%,日内、日间变异系数均小于7.6%。     

超高效液相色谱-串联质谱法测定猪肉、猪肝及猪尿中的阿托品残留

建立了猪肉、猪肝和猪尿中阿托品残留的超高效液相色谱-串联质谱(UPLC-MS/MS)的检测方法。样品经乙腈-0.1%甲酸水(V/V,90:10)溶液提取,Agela Cleanert? PEP-2固相萃取柱净化后,采用UPLC-MS/MS测定,外标法定量。结果表明,猪组织及猪尿中阿托品的检测限为0.2 μg/kg,定量限为0.5 μg/kg。在0.5～2.5 μg/kg添加浓度范围内阿托品的平均回收率78.3%～98.2%之间,批内、批间相对标准偏差均小于15％。该方法简便、快速、灵敏度高、重现性好,适用于猪组织及猪尿中阿托品的含量测定。     

高效液相色谱－串联质谱法检测猪肝组织中氯霉素残留的研究

建立了猪肝组织中氯霉素残留检测的高效液相色谱-串联质谱(LC-MS/MS)法.液相色谱条件为色谱柱为Alltech Altima C18柱(150 mm×3.2 mm,5 μm);流动相为甲醇-水(1∶ 1,V/V);柱温为30 ℃;流速为0.3 mL/min;进样量为20 μL.质谱条件为电喷雾离子源(ESI-),多反应离子监测(MRM)方式进行采集;监测离子质荷比为320.60＞52.20,320.60＞194.15.以氯霉素的同分异构体间位氯霉素作内标,内标法定量.结果表明,氯霉素的线性范围为0.5～10 ng/mL,相关系数R2＝0.999 9;方法检测限为0.1 μg/kg,定量限为0.2 μg/kg;从0.1、0.2、0.4和1.0 μg/kg四个添加浓度检测结果可以看出,方法的平均回收率为96.6%～116.6%(n＝6),批内批间RSD均小于20%.     

鸡皮脂和肾脏中替米考星残留HPLC检测方法的建立

本试验旨在建立鸡皮脂和肾脏组织中替米考星残留量的HPLC测定方法。皮脂和肾脏组织中残留的替米考星用乙腈提取、MCX固相萃取柱净化,采用高效液相色谱-紫外检测法测定。皮脂组织和肾脏组织中替米考星检测限分别为20μg/kg和30μg/kg,定量限分别为35μg/kg和50μg/kg。空白皮脂组织添加替米考星在35～150μg/kg浓度水平,回收率在75%～98%之间,批内与批间变异系数均小于10%;空白肾脏组织添加替米考星在50～500μg/kg浓度水平,回收率在71%～97%之间,批内变异系数小于11%,批间变异系数小于10%。本试验建立的方法快速、准确、灵敏,适用于鸡皮脂和肾脏组织中替米考星残留量的检测。     

分散固相萃取结合液相色谱串联质谱法检测牛可食性组织中泰地罗新残留量

建立了分散固相萃取结合液相色谱串联质谱法检测牛肉、牛脂肪、牛肝和牛肾等可食性组织中的泰地罗新残留量的方法。取牛组织样品经50%(V/V)乙腈溶液提取,加入无水硫酸镁和氯化钠进行脱水和盐析,正己烷脱脂,高速离心分层后,取适量乙腈层溶液经0.1%(V/V)甲酸稀释后,用酸性氧化铝粉末进行样品净化并以10000 r/min离心取上清液,过0.22μm滤膜后上机测定。使用反相色谱柱进行分离,流动相为0.1%甲酸和乙腈溶液,采用梯度程序进行洗脱,三重四级杆质谱进行定性定量分析。结果表明,方法的最低检测限为5μg/kg,最低定量限为10μg/kg,添加含量在10～1000μg/kg范围内线性关系良好(r0.995),对应添加回收率为60%～110%,RSD10%,表明该方法具有较好的准确度与精密度。     

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