鸡蛋中四环素类药物残留量测定的高效液相色谱法研究

建立了鸡蛋中土霉素、四环素、金霉素、多西环素残留量测定的高效液相色谱法。样品经弱酸性缓冲液提取后,HLB固相萃取柱净化后,反相液相色谱分离测定,本方法的检出限为10μg／kg,定量限为50μg／kg。四种四环素类药物在50～1000ng／mL范围内呈线性相关。在100～400ng／g添加浓度范围内,平均回收率为60％～110％,批内变异系数在3．2％～13．7％之间（n=5）,批间变异系数在0．9％-5．3％之间（n=4）。结果表明,该法简单、灵敏、特异性强,适用于鸡蛋中土霉素、四环素、金霉素、多西环素残留量的测定。     

鸡蛋及牛奶中四环素类药物残留量的液相色谱-串联质谱测定法

建立了一种测定鸡蛋及牛奶中四环素类药物残留 液相色谱-串联质谱的方法。样品经Mcllvaine-Na2EDTA缓冲液提取,经快速滤纸过滤,并经加脱脂棉的HLB固相萃取柱净化,洗脱液氮气吹至小于1 mL,加30%甲醇至1mL并混匀,液相色谱-串联质谱法检测,基质匹配标液外标法定量。结果表明,四环素类药物在5 μg/kg~100 μg/kg的浓度范围内呈现良好的线性关系。在鸡蛋及牛奶中四环素类药物的检测限均为2 μg/kg,定量限均为5 μg/kg。在LOQ~2MRL(多西环素为LOQ-10LOQ)添加浓度范围内,四环素类药物的回收率均在81.2~110.0%之间,批内批间变异系数均小于11.4%。该方法各项技术指标均能满足残留检测要求,且方法的重现性良好,满足国内外兽药残留检测的相关规定。     

液相色谱-串联质谱法测定鸡蛋中7种氟喹诺酮类药物的残留量

建立了一种液相色谱-串联质谱法测定鸡蛋中7种氟喹诺酮类药物残留的方法。样品经EDTA-Mcllvaine缓冲液提取,冷冻离心,然后用正己烷脱脂,有效地去除杂质,HLB固相萃取柱净化,氮气吹干浓缩,流动相溶解,进行LC-MS/MS定性定量分析。其中5种氟喹诺酮类药物含量在2.5μg/kg~100μg/kg范围内,线性关系良好,环丙沙星和恶喹酸含量分别在6μg/kg~240μg/kg和0.25μg/kg~10μg/kg范围内,线性关系良好,相关系数均大于0.995 9;添加量在100、200、500μg/kg时,该方法的加标回收率为36.9%~81.2%,相对标准偏差均小于15.8%。该方法对环丙沙星和恶喹酸的检测限分别为1.2μg/kg和0.05μg/kg,定量限为24μg/kg和1μg/kg,其他5种氟喹诺酮类药物的检测限为0.5μg/kg,定量限为10μg/kg,表明所建立的方法适用于鸡蛋中7种氟喹诺酮类药物残留的定性和定量检测。     

高效液相色谱法测定貉子肉中四环素类药物残留

为了建立高效液相色谱法测定貉子肉中四环素类药物的残留,试验采用Na2EDTA-Mcllvaine缓冲溶液超声提取样品中目标化合物,HLB固相萃取小柱净化,通过高效液相紫外检测器测定,外标法定量。结果表明:貉子肉中四环素类药物的方法检出限为47.5～49.6μg/kg,回收率范围为80.3%～97.4%,相对标准偏差为1.9%～5.5%。表明该方法灵敏度高、重现性好,可用于貉子肉中四环素类药物残留的检测。     

高效液相色谱法检测鸡蛋中四环素类药物残留方法研究

试验旨在建立同时检测鸡蛋中土霉素、四环素、金霉素和多西环素4种四环素类药物残留的高效液相色谱法。将鸡蛋样品用0.1 mol/L Na₂EDTA-Mcllvaine缓冲溶液提取,通过Oasis MAX固相萃取柱净化,以乙腈—三氟乙酸(0.01 mol/mL)为流动相,梯度洗脱,反相液相色谱分离测定。结果显示,4种四环素类药物在30~1 000 ng/g范围内呈良好线性关系,检出限为10 ng/g,定量限为50 ng/g,平均回收率为67.3%~81.4%,日内相对标准偏差为2.7%~14.3%,日间相对标准偏差为0.9%~5.0%。本研究建立的高效液相色谱法可同时检测鸡蛋中的土霉素、四环素、金霉素和多西环素的药物残留,该方法灵敏度、准确度和精密度较高,操作快速、简单。     

基于PRIME HLB快速前处理技术的鸡蛋中38种药物残留快速检测方法研究及其在风险监测中的应用

采用超高效液相色谱-串联质谱法(UPLC-MS/MS),结合PRIME HLB快速通过式前处理技术,优化样品前处理及色谱-质谱条件,建立了同时提取、动态多反应监测(MRM)的测定β-内酰胺类、抗病毒类、大环内酯类、喹诺酮类、四环素类、林可胺类、磺胺类、氯霉素类和氟虫腈及其代谢物共9类38种药物残留的新方法。鸡蛋样品经80%(V/V)乙腈-水溶液(含0.02 mol/L EDTA)提取后,PRIME HLB固相萃取柱净化,基质匹配外标法定量。38种药物在3个不同浓度水平下,平均回收率为71.4%～108.2%;相对标准偏差RSD为0.7%～8.1%;检出限(LOD,S/N=3)和定量限(LOQ,S/N=10)分别为0.01～1.0μg/kg和0.05～3.5μg/kg。本方法简便快速,灵敏可靠,适用于鸡蛋中药物多残留高通量快速检测分析。     

新型反相固相萃取吸附剂测定鸡蛋中4种氟喹诺酮类药物残留量

建立了一种使用新型反相固相萃取吸附剂(PRiME HLB)的前处理净化流程,采用高效液相色谱-荧光检测器同时测定鸡蛋中环丙沙星、达氟沙星、恩诺沙星和沙拉沙星残留量的方法。试样经乙腈∶0.2%甲酸水溶液(80∶20)提取,PRiME HLB固相萃取柱净化后进行测定,外标法定量。实验结果表明:(1)在鸡蛋中环丙沙星、恩诺沙星和沙拉沙星的检测限为0.75μg/kg,达氟沙星的检测限为0.15μg/kg;在0.005~0.5μg/mL质量浓度范围(达氟沙星在0.001~0.2μg/mL浓度范围)内线性回归关系良好(r0.99999)。(2)环丙沙星、恩诺沙星和沙拉沙星的添加量为0.005、0.05、0.5μg/mL(达氟沙星0.001、0.02、0.2μg/mL)时,方法的添加回收率在74.24%~98.78%,RSD5.15%。本方法适用于鸡蛋中4种氟喹诺酮类药物残留量的测定。     

超高效液相色谱-串联质谱法测定鸡蛋中的金刚烷胺

笔者建立了超高效液相色谱-串联质谱法(UPLC/MS/MS)检测鸡蛋中金刚烷胺的新方法。采用三氯乙酸溶液和庚烷磺酸钠溶液作为样品的提取溶液,经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和定量分析。结果显示,金刚烷胺在1μg/L~50μg/L范围内线性关系良好,相关系数r大于0.9990;空白鸡蛋在2μg/kg、5μg/kg、10μg/kg添加浓度上的回收率均在75%~112%之间;批内及批间相对偏差(RSD)均小于18%;本方法的定量限为2μg/kg(S/N10),检测限为1μg/kg(S/N3)。     

液相色谱-串联质谱法测定蜂产品中20种喹诺酮类药物的残留量

建立了同时测定蜂蜜和蜂王浆中20种喹诺酮类药物的超高效液相色谱-串联质谱方法。以磷酸盐缓冲液(p H 3.0)溶液提取样品中的待测物,HLB固相萃取柱净化,液相色谱-串联质谱法测定,外标法定量。药物在1~50 ng/m L浓度范围内线性关系良好,相关系数均大于0.99。方法的检出限为0.5μg/kg,定量限为1.0μg/kg,在蜂蜜和蜂王浆中添加浓度范围为1.0~5.0μg/kg,其平均回收率为69.0%~105.1%,相对标准偏差在1.4%~14.7%之间。方法抗干扰能力强、分析速度快、灵敏度高,适用于蜂产品中喹诺酮类药物残留量的测定。     

超高效液相色谱-四级杆-静电场轨道肼高分辨质谱同时快速筛查与确证猪粪中33种磺胺类及四环素类药物

建立了超高效液相色谱-四级杆-静电场轨道肼高分辨质谱(UPLC-Q-Exactive Orbitrap)同时快速筛查与确证猪粪中共33种磺胺类及四环素类药物的分析方法和目标化合物的质谱数据库。猪粪样品经Na_2EDTA-Mcllvaine缓冲液及乙腈提取,利用通过式固相萃取柱PRiME HLB净化后上机检测。结果表明,33种目标药物添加浓度在50μg/kg检出限浓度时可全部检出,回收率集中在61.7%～118.4%。该方法高效、灵敏、准确,将粪便作为活体检材,减少了对活体动物的破坏性,同时适用于猪粪中多种抗生素的快速定性确证,有利于掌握养殖业用药情况。     

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 -