UPLC-MS/MS法测定动物源性食品中氯苯胍及其代谢物残留

为快速有效地检测动物源性食品中氯苯胍及其代谢物残留,研究建立一种在鸡蛋、鸡肉、牛肉、鱼肉和猪肉5种动物源性食品中,同时检测氯苯胍及其代谢物（对氯苯甲酸、对氯苯甲酰氨基乙酸）残留的超高效液相色谱-串联质谱（UPLC-MS/MS）法。样品经过2%（V/V）甲酸乙腈溶液提取,无水硫酸钠去除水分,氮吹浓缩后甲醇复溶,正己烷除脂,高速冷冻离心,得到净化后的样品进行上机测定。选用Waters ACQUITY UPLC BEH C18色谱柱（2.1 mm×100 mm,1.7 μm）,将甲醇-0.1%甲酸水溶液作为流动相进行梯度洗脱。通过多反应检测（MRM）,在正/负离子模式下,采用基质匹配外标法,同时对3种化合物进行定性和定量分析。结果显示,氯苯胍、对氯苯甲酸和对氯苯甲酰氨基乙酸在各自浓度范围内线性关系良好,相关系数R²>0.999。氯苯胍的检出限（LOD）和定量限（LOQ）分别为0.5和1.0 μg/kg,对氯苯甲酸的LOD和LOQ分别为2.5和5.0 μg/kg,对氯苯甲酰氨基乙酸的LOD和LOQ分别为1.0和2.5 μg/kg。不同基质中,3种化合物在4个添加水平（氯苯胍：1.0、25、50、100 μg/kg;对氯苯甲酸：5.0、25、50、100 μg/kg;对氯苯甲酰氨基乙酸：2.5、25、50、100 μg/kg）的平均回收率为76.0%~95.9%,相对标准偏差（RSDs,n=6）为2.6%~10.6%。基质效应|ME|为0.2%~26.2%,其中氯苯胍在鸡蛋中,对氯苯甲酰氨基乙酸在鸡肉、牛肉和鱼肉中存在较强的基质效应（|ME|>20%）,空白猪肉可作为代表基质用于3种化合物的定量分析。本方法前处理简单,灵敏度较高,重现性好,可用于动物源食品中氯苯胍及其代谢物残留的测定。     

液相色谱-三重四级杆/线性离子阱复合质谱技术检测牛可食性组织中吡利霉素的残留

建立了一种可准确定性定量检测4种牛可食性组织中吡利霉素残留的液相色谱-三重四级杆/线性离子阱（LC-Q-trap MS）复合质谱分析技术。牛肌肉、脂肪、肾脏和肝脏样品经5%甲酸乙腈提取,captiva EMR-Lipid柱净化。以0.1%甲酸水溶液和0.1%甲酸乙腈溶液为流动相,经Kinetex F5 色谱柱分离后,用多反应监测联合信息依赖性采集与增强子离子扫描（MRM-IDA-EPI）模式检测,基质匹配标准溶液校正,外标法定量。结果表明：吡利霉素于牛肌肉和脂肪中在1～100 ng/mL的浓度范围内,于牛肾脏和肝脏中在1～400 ng/mL浓度范围内均呈现良好的线性关系,关系数（R2）均大于0.990;在4种空白组织中吡利霉素的检测限均为5 μg/kg,定量限均为1相0 μg/kg。吡利霉素在牛肌肉和牛脂肪10～200 μg/kg、牛肾脏10～800 μg/kg,以及牛肝脏10～2000 μg/kg添加浓度范围内的回收率范围在60.2%～101%之间;批内与批间相对标准偏差均小于13%。该方法具有简便快速、灵敏度高、定性准确,重复性好等特点,可以满足上述组织中吡利霉素残留检测的要求。     

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。     

UPLC-MS/MS法测定动物源性食品中氯苯胍及其代谢物残留

为快速有效地检测动物源性食品中氯苯胍及其代谢物残留,研究建立一种在鸡蛋、鸡肉、牛肉、鱼肉和猪肉5种动物源性食品中,同时检测氯苯胍及其代谢物(对氯苯甲酸、对氯苯甲酰氨基乙酸)残留的超高效液相色谱-串联质谱(UPLC-MS/MS)法。样品经过2%(V/V)甲酸乙腈溶液提取,无水硫酸钠去除水分,氮吹浓缩后甲醇复溶,正己烷除脂,高速冷冻离心,得到净化后的样品进行上机测定。选用Waters ACQUITY UPLC BEH C18色谱柱(2.1 mm×100 mm,1.7μm),将甲醇—0.1%甲酸水溶液作为流动相进行梯度洗脱。通过多反应检测(MRM),在正/负离子模式下,采用基质匹配外标法,同时对3种化合物进行定性和定量分析。结果显示,氯苯胍、对氯苯甲酸和对氯苯甲酰氨基乙酸在各自浓度范围内线性关系良好,相关系数R~20.999。氯苯胍的检出限(LOD)和定量限(LOQ)分别为0.5和1.0μg/kg,对氯苯甲酸的LOD和LOQ分别为2.5和5.0μg/kg,对氯苯甲酰氨基乙酸的LOD和LOQ分别为1.0和2.5μg/kg。不同基质中,3种化合物在4个添加水平(氯苯胍:1.0、25、50、100μg/kg;对氯苯甲酸:5.0、25、50、100μg/kg;对氯苯甲酰氨基乙酸:2.5、25、50、100μg/kg)的平均回收率为76.0%～95.9%,相对标准偏差(RSDs,n=6)为2.6%～10.6%。基质效应|ME|为0.2%～26.2%,其中氯苯胍在鸡蛋中,对氯苯甲酰氨基乙酸在鸡肉、牛肉和鱼肉中存在较强的基质效应(|ME|20%),空白猪肉可作为代表基质用于3种化合物的定量分析。本方法前处理简单,灵敏度较高,重现性好,可用于动物源食品中氯苯胍及其代谢物残留的测定。     

液相色谱-三重四极杆/线性离子阱复合质谱技术检测牛可食性组织中吡利霉素的残留

建立了一种可准确定性定量检测4种牛可食性组织中吡利霉素残留的液相色谱-三重四极杆/线性离子阱(LC-Q-trap MS)复合质谱分析技术。牛肌肉、脂肪、肾脏和肝脏样品经5%甲酸乙腈提取,captiva EMR-Lipid柱净化。以0.1%甲酸水溶液和0.1%甲酸乙腈溶液为流动相,经Kinetex F5色谱柱分离后,用多反应监测联合信息依赖性采集与增强子离子扫描(MRM-IDA-EPI)模式检测,基质匹配标准溶液校正,外标法定量。结果表明:吡利霉素于牛肌肉和脂肪中在1～100 ng/mL的浓度范围内,于牛肾脏和肝脏中在1～400 ng/mL浓度范围内均呈现良好的线性关系,相关系数(R²)均大于0.990;在4种空白组织中吡利霉素的检测限均为5μg/kg,定量限均为10μg/kg。吡利霉素在牛肌肉和牛脂肪10～200μg/kg、牛肾脏10～800μg/kg,以及牛肝脏10～2000μg/kg添加浓度范围内的回收率范围在60.2%～101%之间;批内与批间相对标准偏差均小于13%。该方法具有简便快速、灵敏度高、定性准确,重复性好等特点,可以满足上述组织中吡利霉素残留检测...     

超高效液相色谱-串联质谱法检测牛可食性组织中氟佐隆残留

建立了一种检测牛可食性组织中氟佐隆残留的超高效液相色谱-串联质谱法。牛肌肉、肝脏、肾脏和脂肪样品经90%乙腈溶液提取，高速离心去除蛋白质等杂质，EMR-Lipid柱净化。以0.1%甲酸乙腈溶液和0.1%甲酸水溶液为流动相，在C₁₈色谱柱上分离。在电喷雾正离子(ESI⁺)模式下采用多反应监测模式(MRM)检测，基质匹配标准溶液外标法定量。结果表明：氟佐隆对牛肌肉在1～100 ng/mL浓度范围内，对牛肝脏、肾脏和脂肪在1～500 ng/mL浓度范围内均呈现良好的线性关系，决定系数(R²)均大于0.990;在4种牛可食性组织中氟佐隆的检测限均为5μg/kg,定量限均为10μg/kg。氟佐隆在牛肌肉10～400μg/kg、牛肝脏和牛肾脏10～1000μg/kg、牛脂肪10～14000μg/kg空白添加浓度范围内的回收率为72.0%～98.6%;批内与批间相对标准偏差均小于15%。该方法具有简便快捷、选择性好、定性准确，重复性好等特点，可以满足上述组织中氟佐隆残留检测的要求。     

同位素内标-液质联用法测定鸡可食性组织中替米考星残留量

建立了鸡四种可食性组织中替米考星的液相色谱串联质谱内标法。样品经磷酸二氢钾缓冲液和乙腈提取后,C18固相萃取柱净化,以0.1%甲酸乙腈溶液和0.1%甲酸水为流动相,液相色谱串联质谱法测定,内标法定量。试验结果表明：鸡四种可食性组织中替米考星在1 μg/kg~100 μg/kg的浓度范围内呈线性关系,相关系数r大于0.99;替米考星在鸡四种可食性组织中的检测限为0.5 μg/kg,定量限为1 μg/kg;四种组织中替米考星添加浓度为1 μg/kg~4800 μg/kg时,批间平均回收率为94.6%~100.9%,批内、批间变异系数在1.11%-5.06%范围之间。本方法适用于鸡四种可食性组织中替米考星含量的测定。     

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。     

超高效液相色谱串联质谱快速检测猪肉中的沃尼妙林残留

建立了检测猪肉样品中新型兽药盐酸沃尼妙林残留的快速超高效液相色谱-串联质谱（UPLC-MS/MS）确证方法。样品使用乙腈提取,在提取过程中同时加入正己烷去除脂质杂质,离心后取乙腈提取液,浓缩至干,用1 mL 0.1%甲酸水∶乙腈（60∶40,V∶V）复溶上机。以反相C18柱作为分离柱,0.1%甲酸乙腈和0.1%甲酸水为流动相,进行梯度洗脱。方法的检测限为10μg/kg,定量限为20μg/kg;在三个浓度水平（20、50、100μg/kg）下进行添加实验,平均回收率均大于92.60%,批内相对标准偏差为1.31%~6.80%,批间相对标准偏差为3.02%~4.60%。此方法简便迅速且稳定有效,适合快速检测猪肌肉中的沃尼妙林残留。     

液相色谱-串联质谱法检测猪肉、鸡肉组织中维吉尼霉素M1残留量的研究

为了建立可同时检测猪肉、鸡肉组织中维吉尼霉素M_1药物残留的液相色谱-串联质谱分析方法,样品选用0.2%甲酸的乙腈/水(80∶20,V/V)溶液为提取液,经Oasis PRi ME HLB固相萃取小柱净化,在液相色谱-串联质谱仪上进行检测。结果表明,维吉尼霉素M_1在0.25~200 ng/m L浓度范围内呈现良好的线性关系,相关系数(R2)大于0.999。猪肉、鸡肉组织中维吉尼霉素M_1的检测限为0.5μg/kg,定量限为2.0μg/kg。在2~200μg/kg(2MRL)添加浓度水平上,回收率范围为80%~100%,批内、批间RSD均小于8.0%。该方法具有简便快捷、灵敏度高、定性准确等特点。     

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