HPLC检测草鱼组织中阿维菌素和伊维菌素的多残留

建立了草鱼肌肉(包括皮)中阿维菌素和伊维菌素的多残留检测方法.样品用乙腈提取,正己烷脱脂净化,多拉菌素作内标,经1-甲基咪唑和三氟乙酸酐的乙腈溶液在室温下避光衍生化并在甲醇中水解后,进行HPLC-FLD检测分析.结果表明,阿维菌素和伊维菌素在5～100 ng/g范围内具有良好线性,检测限分别为1.0 ng/g和1.2 ng/g,定量限分别为3.4 ng/g和4.0 ng/g,日间提取回收率分别为96.42%～103.10%和94.23%～101.76%,日内和日间变异系数分别小于4.37%、6.82%和6.73%、8.84%.该方法高效、灵敏、简便,其灵敏度、回收率和重现性等符合有关兽药残留检测要求,可用于草鱼肌肉中阿维菌素和伊维菌素的多残留检测.     

高效液相色谱法测定乳品与饲料中阿维菌素类药物残留

建立乳品与饲料中阿维菌素类药物(埃普利诺菌素、阿维菌素、多拉菌素和伊维菌素)残留液相色谱的测定方法。乙腈为提取剂,tC18固相萃取小柱净化,三氟乙酸酐和N-甲基咪唑柱前衍生,C18柱分离,甲醇-乙腈的混合溶剂与水梯度洗脱,液相色谱仪荧光检测器检测,外标法定量。每1 000 g乳粉(或每1 000 mL液态乳)中阿维菌素添加量为1.5 μg时,回收率大于95％。本方法液态乳、酸乳、乳粉的定量限为2μg/kg,饲料的定量限为10 μg/kg。该方法具有结果准确、操作简便、重复性好等优点,可用于乳品和饲料中阿维菌素类药物残留的检测。     

草鱼组织中阿维菌素和伊维菌素的多残留检测

建立了草鱼肌肉（包括皮）中阿维菌素和伊维菌素的多残留检测方法。样品用乙腈提取,正己烷脱脂净化,多拉菌素作内标,经1-甲基咪唑和三氟乙酸酐的乙腈溶液在室温下避光衍生化并在甲醇中水解后,进行HPLC-FLD检测分析。结果表明,阿维菌素和伊维菌素在5~100 ng/g范围内具有良好线性,检测限分别为1.0 ng/g和1.2 ng/g,定量限分别为3.4 ng/g和4.0 ng/g,日间提取回收率分别为96.42%~103.10%和94.23%~101.76%,日内和日间变异系数分别小于4.37%、6.82%和6.73%、8.84%。该方法高效、灵敏、简便,其灵敏度、回收率和重现性等符合有关兽药残留检测要求,可用于草鱼肌肉中阿维菌素和伊维菌素的多残留检测。     

液相色谱-串联质谱法检测牛奶中4种阿维菌素类药物残留量的研究

建立了一种可同时检测牛奶中4种阿维菌素类药物(阿维菌素、伊维菌素、多拉菌素和埃谱利诺菌素)残留的液相色谱-串联质谱方法(LC-MS/MS)。牛奶样品经乙腈提取,高速离心去除蛋白质等杂质,C18柱净化。以0.1%甲酸水溶液和0.1%甲酸乙腈溶液为流动相进行洗脱,流速0.4 m L/min,采用基质匹配标准溶液外标法定量。结果表明:阿维菌素、伊维菌素、多拉菌素和埃谱利诺菌素在0.5~100 ng/m L浓度范围内均呈现良好的线性关系,相关系数(R2)均大于0.996;4种阿维菌素类药物的定量限均为0.5μg/kg。阿维菌素在0.5~5μg/kg添加浓度范围内,伊维菌素在0.5~20μg/kg添加浓度范围内,多拉菌素在0.5~30μg/kg添加浓度范围内,埃谱利诺菌素在0.5~40μg/kg添加浓度范围内,回收率为66.4%~120%;批内与批间相对标准偏差均小于20%。该方法具有简便快速、灵敏度高、定性准确,重复性好等特点,可以满足牛奶中4种阿维菌素类药物残留检测的要求。     

动物性食品中阿维菌素类药物残留检测高效液相色谱法的优化

为探索方便快捷且符合兽药残留试验技术规范要求的阿维菌素类药物残留检测方法,对农业部1025号公告-5-2008动物性食品中阿维菌素类药物残留检测-酶联免疫吸附法、高效液相色谱法和液相色谱-串联质谱法中的高效液相色谱法进行优化,改进了样品提取后储存条件、净化条件和衍生化条件。牛肝样品经2次乙腈提取后,用乙腈-水-三乙胺储存备用,用C18固相萃取柱分离,1-甲基咪唑-乙腈、三氟乙酸酐-乙腈、冰乙酸和三乙胺衍生化,乙腈作流动相,高效液相色谱法分析。优化法试验结果显示,爱普菌素、阿维菌素、伊维菌素和多拉菌素等4种阿维菌素类药物在2～200μg/L的浓度范围内,标准曲线线性良好,相关系数均大于0.999 2;方法检测限2μg/kg,定量限5μg/kg;加标回收率在83%～93%,批内变异系数小于14%,批间变异系数小于11%。表明优化法符合兽药残留试验技术规范的要求,准确度和精密度较好,检测时间和成本低于标准法,可用于动物性食品中阿维菌素类药物残留的检测。     

大环内酯类抗寄生虫药物的研究进展

大环内酯类抗寄生虫药由两大类组成,即阿维菌素类（包括阿维菌素、伊维菌素、多拉菌素、塞拉菌素、埃玛菌素和埃普利诺菌素）和米尔贝霉素类（包括米尔贝肟和莫西菌素）。其中阿维菌素和伊维菌素（阿维菌素的衍生物,含有双氢阿维菌素B1a 80％以上,含有双氢阿维菌素B1b 20％以下）是目前在兽医临床应用最广泛的两种广谱、高效、低毒的大环内脂类抗寄生虫药物。     

牛肌肉中阿维菌素类药物残留的免疫亲和色谱—高效液相色谱荧光检测方法的研究简

本研究旨在建立以免疫亲和色谱（IAC）柱为净化手段的高效液相色谱荧光检测方法（HPLC-FLD）,可同时检测牛肌肉组织中的阿维菌素、伊维菌素、多拉菌素和埃普里诺菌素残留。样品用甲醇提取,IAC柱净化,以乙酸酐—甲基咪唑的乙腈溶液作衍生化试剂,96 ℃条件下,完全衍生化100 min。在5、10、50和100 ng/g添加水平下,牛肌肉组织中4种药物添加回收率为77.3%～119.5％,变异系数为1.5%～18.9％,方法的检测限为0.8 ng/g。该方法可用于检测牛肌肉组织中的阿维菌素类药物残留。     

液相色谱法测定猪组织中阿维菌素类药物残留量

动物组织中残留的阿维菌素、依维菌素和多拉菌素经乙腈提取,碱性氧化铝固相萃取柱净化后,与荧光衍生化试剂反应,产物用高效液相色谱(荧光检测器)进行检测,实现了阿维菌素类药物的残留分析.本方法在猪组织中测定阿维菌素类药物的检测限为1μg/kg;在猪组织中添加浓度为1、2、5μg/kg时的回收率为55%～75%.     

阿维菌素类药环境毒理学研究进展

阿维菌素类药物(AVMs)是一种大环内酯类抗生素,是目前世界上使用最为广泛寄生虫药物,它一共有5种;爱比菌素(abamectin,ABA)、伊维菌素(ivermectin,IVM)、多拉菌素(doramectin,DOR)、埃普利诺菌素(eprinometin,EPR)和塞拉菌素(selamectin,SEL).     

阿维菌素类药物残留检测衍生化研究

本文优化了猪、牛组织及奶和奶粉中阿维菌素类药物残留检测的衍生化方法。经过对反应温度、时间及光照的系统摸索,采用N-甲基咪唑-乙腈(1+1,v/v)与三氟乙酸酐-乙腈(1+2,v/v)为衍生化试剂,经65℃避光反应15 min进行衍生化。该衍生化方法用时短、效率高,进一步提高了检测方法的灵敏度,使得乙酰氨基阿维菌素、阿维菌素、伊维菌素和多拉菌素在牛、羊奶中的定量限为0.5μg/kg;在猪、牛组织和奶粉中的定量限为5μg/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.     

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.     

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.     

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