液相色谱-质谱联用分析饲料中新型的β2-肾上腺素能激动剂——齐帕特罗

建立了饲料中齐帕特罗的液相色谱-质谱联用(LC-MS)检测方法.液相色谱条件为Waters AntantisTM C18色谱柱(150 mm×2.1 mm,3μm);柱温30℃;流动相为乙腈-0.2%甲酸(892,V/V);流速0.2 mL/min;进样量20μL.质谱条件为电喷雾离子源(ESI+),选择离子监测质荷比(m/z)为262、244、202、185带正电荷的准分子离子和碎片离子.齐帕特罗的线性范围为0.01～4μg/mL,最低定量检测限0.01μg/g,回收率为(90±10)%.     

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%.     

牛奶中吡利霉素残留检测高效液相色谱-串联质谱法研究

建立了牛奶中吡利霉素残留检测的高效液相色谱-串联质谱(HPLC-MS/MS)法。液相色谱条件为:色谱柱为Waters XBridge C18柱(150 mm×2.1 mm,5μm),流动相为乙腈-0.01mol/L乙酸铵溶液(30∶70,V/V),柱温为30℃,流速为0.2 mL/min,进样量为10μL。质谱条件为:电喷雾离子源(ESI ),多反应监测(MRM)方式进行采集;监测离子质荷比(m/z)为411.5>112.0,411.5>363.4。以吡利霉素的同分异构体异吡利霉素作内标,内标法定量。结果表明:吡利霉素的线性范围为20~400 ng/mL,相关系数R2=0.999 9;方法检测限为2 ng/mL,定量限为5ng/mL;从50、100和150 ng/mL三个添加浓度检测结果可以看出,方法的平均回收率为90.4%~104.3%(n=6),批内、批间RSD均小于5%。     

超高效液相色谱-串联质谱法测定饲料中的己烯雌酚

本文建立了饲料中己烯雌酚的高效液相色谱—串联质谱检测方法(UPLC-MS/MS)。色谱条件:色谱柱为ACQUITY UPLC BEH C18柱2.1mm×50mm1.7μm;流动相为乙腈—水(50:50,v/v),流速0.2mL/min;进样体积10μL;柱温35℃。采用负电喷雾离子源,在多反应监测(MRM)模式下进行分析,外标法定量,3对定性离子对分别为:m/z320.90151.85、320.90256.92和320.90193.90,定量离子对为320.90151.85。在0.1～500μg/L浓度范围内呈良好的线性,相关系数r0.999。在1、5、20mg/kg3个添加水平,平均回收率75.2%～97.6%,日内变异系数在2.1%～6.3%之间,日间变异系数在3.2%～9.7%,检测限为10μg/kg。     

超高效液相色谱-串联质谱法测定原料乳和奶粉中三聚氰胺的含量

该试验建立了使用超高效液相色谱-串联四极杆质谱测定原料乳和奶粉中三聚氰胺含量的检测方法.用三氯乙酸溶液和乙酸铅提取,提取液经MCX固相萃取柱净化后用UPLC-MS-MS进行检测.色谱条件:CAPCELL PAK CR1:4柱(2.0 mm×100 mmi.d.,5 μm),流动相:乙腈-0.01 mol/L乙酸铵溶液,梯度洗脱流速0.3ml/min.采用正离子模式的电喷雾质谱检测,以一级质谱得到的准分子离子m/z 126.8作为母离子,进行碰撞诱导解离(CID)二级质谱(MS2)分析,选择母离子和MS2的碎片离子m/z 84.9、67.8定性确证.提取m/z 84.9离子质量色谱峰面积定量.基质标准线性范围为0.01～1.00 μg/ml,检出限10 μg/kg(S/N=10),原料乳回收率为82.4%～97.8%,奶粉回收率为80.7%～95.7%.     

HPLC-MS/MS法测定饲料中硫酸新霉素的含量

试验建立液相色谱-串联质谱仪(HPLC-MS/MS)测定饲料中硫酸新霉素含量的方法。饲料中硫酸新霉素经磷酸盐缓冲液提取,C18固相萃取柱净化,用高效液相色谱-串联质谱仪进行测定,液相色谱采用C18(100.0 mm×2.1 mm,2.4μm)色谱柱,乙腈+20.0 mmol/L七氟丁酸溶液作为流动相,梯度洗脱。质谱采用正电喷雾离子源,多反应检测(MRM)模式测定。结果表明:硫酸新霉素在0.1~5.0μg/m L质量浓度范围内线性关系良好(r=0.997 9);方法检测限为0.2 mg/kg,定量限为0.4 mg/kg;方法回收率为75.8%~98.2%。     

液相色谱串联质谱法测定猪肉中的安定残留

建立了猪肌肉中安定的高效液相色谱-串联质谱检测方法。用乙腈提取猪肌肉组织中的药物,经HLB固相柱净化,采用正电喷雾离子源,在多反应监测(MRM)模式下测定,三对定性离子对(m/z)分别为:285.4>154.0、285.4>193.0和285.4>257.0,定量离子对m/z为285.4>154.0。结果表明:安定在0.1~100 ng/mL内线性良好,相关系数r为0.998 5。在0.5、2、10μg/kg添加水平下,加标回收率为68.2%~97.6%,变异系数(CV)在2.2%~7.8%之间,检测限为0.1μg/kg,定量限为0.5μg/kg。     

液相色谱-三重四极杆/线性离子阱复合质谱技术检测牛奶中莫昔克丁残留

建立了牛奶中莫昔克丁残留检测的液相色谱-三重四极杆/线性离子阱复合质谱技术(LC-QTRAP)。样品用乙腈提取后,用C18固相萃取柱净化,上机测试。液相色谱条件:色谱柱为BEH C18(50 mm×2.1 mm,1.7μm),流动相为0.1%甲酸水溶液+0.1%甲酸乙腈溶液,梯度洗脱,流速为0.4 mL/min,柱温为30℃,进样量为5μL。质谱条件:电喷雾正离子源(ESI~+),采用多反应监测-信息依赖扫描-增强子离子扫描(MRM-IDA-EPI)方式采集。结果表明:在牛奶中,莫昔克丁在1～80 ng/mL基质匹配标准溶液浓度范围内均呈现良好的线性关系,相关系数(R~2)大于0.990,定量限为2μg/kg。牛奶中莫昔克丁在2、40和80μg/kg三个添加浓度平均回收率都在60%～120%之间,批内、批间RSD均小于15%。该方法简便快捷、定性准确、灵敏度高,回收率和精密度满足残留检测要求。     

猪肉组织中四环素类药物残留检测——高效液相色谱-串联质谱法研究

建立了猪肉组织中四环素类药物残留检测的高效液相色谱-串联质谱方法.色谱条件为色谱柱为XBridge C18柱(150 mm×2.1 mm,5 μm),流动相为0.3%甲酸乙腈溶液 0.3%甲酸水溶液;柱温 20 ℃,流速0.2 mL/min;进样量20 μL.质谱条件为电喷雾离子源(ESI );多反应监测(MRM)方式采集.外标法定量.结果表明,四环素、土霉素和金霉素在10～400 ng/mL浓度范围内呈现良好线性,相关指数R2均大于0.999;方法检测限为5 ng/g,定量限为10 ng/g.50、100和200 ng/g三个添加浓度的平均回收率为72.3%～94.6%,批内批间RSD均小于20%.     

高效液相色谱-质谱/质谱法检测生鲜乳中孕酮残留量方法的建立和优化

为了建立生鲜乳中孕酮的高效液相色谱-质谱/质谱检测方法,试验采用生鲜乳样品经甲醇溶液提取后,用C_(18)固相萃取柱净化后,再经电喷雾离子源高效液相色谱-质谱/质谱测定,保留时间和选择离子丰度比定性,外标法定量。结果表明:孕酮在0.1~5.0 ng/mL浓度范围内呈良好线性相关,相关系数为0.999 9,建立方法的检出限为0.02μg/kg,定量限为0.04μg/kg,在0.1~5.0 ng/m L加标浓度范围内,方法的回收率为79.6%~105.1%,相对标准偏差≤8.9%。与行业标准相比,试验建立方法的检出限和定量限明显降低,增强了方法灵敏度,适用于牧场生鲜乳中孕酮残留的检测。     

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.     

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.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

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

Tropical Animal Health and Production -