牛可食性组织中加米霉素残留量的液相色谱-串联质谱检测方法的研究

本试验建立了牛可食性组织中加米霉素残留量检测的制样和高效液相色谱-串联质谱检测方法,适用于牛组织中加米霉素残留量的测定。牛组织(牛的肌肉、肝脏、肾脏和脂肪)经绞碎、均质后,样品经0. 1 mol/L磷酸二氢钾缓冲液提取,Oasis HLB固相萃取柱净化,高效液相色谱-串联质谱法检测,内标法定量。该方法特异性好,空白样品无干扰。该方法的检测限为1μg/kg,定量限为2μg/kg,基质匹配标准曲线范围为5μg/L～500μg/L,相关系数 0. 99;牛肌肉和肾脏组织在2、50、100、200μg/kg四个添加浓度的平均回收率为93. 56%～103. 31%,批内变异系数≤8. 67%,批间变异系数≤6. 70%;牛肝脏组织在2、100、200、400μg/kg四个添加浓度的平均回收率为94. 37%～102. 52%,批内变异系数≤5. 70%,批间变异系数≤4. 61%;牛脂肪组织在2、10、20、40μg/kg四个添加浓度的平均回收率为100. 95%～105. 58%,批内变异系数≤5. 89%,批间变异系数≤4. 52%。     

高效液相色谱法检测多种动物组织中氟喹诺酮类药物残留量的研究

建立了猪、牛、羊、鸡、兔的肌肉、脂肪、肝脏和肾脏四种组织中环丙沙星、达氟沙星、恩诺沙星、沙拉沙星和二氟沙星残留量检测的高效液相色谱法。试样经磷酸盐溶液提取,C18固相萃取柱浓缩净化后,用高效液相色谱分析,荧光检测器检测,外标法定量。5种药物在0.1～100μg/L浓度范围内线性关系良好。环丙沙星、恩诺沙星、沙拉沙星和二氟沙星在五种动物肌肉、脂肪组织中的定量限为5μg/kg,在肝脏、肾脏组织中的定量限为10μg/kg;达氟沙星在肌肉、脂肪组织中的定量限为1μg/kg,在肝脏、肾脏组织中的定量限为2μg/kg。在指定的三个浓度添加水平下,5种药物在各组织中的平均回收率为62%～103%;批内变异系数为0.30%～18%,批间变异系数为1.0%～17%。该方法操作简单,准确度和精密度好,动物品种及动物组织覆盖范围广,可以很好地满足实际检测工作的需要。     

高效液相色谱-串联质谱法检测猪可食性组织中加米霉素残留

为了建立一种可靠、灵敏的检测猪可食性组织中加米霉素残留量的高效液相色谱-串联质谱方法,本试验将猪组织(肌肉、肝脏、脂肪和肾脏)经绞碎、均质后,用乙腈提取,乙腈饱和正己烷去脂,固相萃取柱净化,Kinetex C18色谱柱梯度洗脱,在电喷雾正离子下以多反应监测模式检测,内标法定量。结果显示,该方法的检测限和定量限分别为3μg/kg和5μg/kg;加米霉素在5～1 000μg/kg浓度范围内,峰面积与浓度的线性关系良好;猪肌肉、肝脏和脂肪在5、50、100μg/kg和200μg/kg四个添加浓度的平均回收率为70.20%～90.75%,批间变异系数≤11.94%;猪肾脏在5、150、300μg/kg和600μg/kg四个添加浓度的平均回收率为66.69%～87.46%,批间变异系数≤9.95%。结果表明该方法灵敏、准确,可满足兽药残留检测的要求。     

高效液相色谱法检测羊鸡组织中氟苯达唑、噻苯达唑及其代谢物残留量的研究

建立了一种可同时检测羊组织（肌肉、肝脏、肾脏、脂肪）、鸡组织（肌肉、肝脏）中氟苯达唑及代谢物2-氨基氟苯达唑、噻苯达唑及代谢物5-羟基噻苯达唑药物残留的高效液相色谱检测方法。结果表明：氟苯达唑及代谢物2-氨基氟苯达唑、噻苯达唑及代谢物5-羟基噻苯达唑在0.02～1.5μg/mL浓度范围内呈良好的线性关系r,均大于0.999。方法的定量限为20μg/kg。在鸡组织（肌肉、肝脏）中,两种药物及其代谢物在20～800μg/kg的添加浓度范围内,其回收率范围在60%～100%之间;在羊组织（肌肉、肝脏、肾脏、脂肪）中,两种药物及其代谢物在20～200μg/kg的添加浓度范围内,其回收率范围在60%～100%之间;批内变异系数均小于15%、批间变异系数均小于20%。     

妥曲珠利在肉鸡组织中残留的研究

用高效液相色谱法(HPLC)检测肉鸡肌肉、肝脏和肾脏组织中妥曲珠利的残留量。将妥曲珠利以20、200和2 000μg/kg的含量分别添加到空白组织中,测得肌肉、肝脏和肾脏组织的回收率大于75%,变异系数均低于7%。用该方法测定肌肉、肝脏和肾脏组织中妥曲珠利的最低检测限为10μg/kg。肉鸡分别在第9,10,16,17,23,24天以8 mg/kg的剂量灌服2.5%妥曲珠利溶液,每天给药1次。最后一次给药后测定不同组织中妥曲珠利的浓度。停药后肌肉、肝脏、肾脏组织中妥曲珠利的残留量逐渐下降;停药第6天后肌肉中检测不到妥曲珠利,停药后第7天肝脏和肾脏组织中均检测不到。     

HPLC法测定鸡肉中恩诺沙星、环丙沙星残留的研究及应用

建立高效液相色谱(HPLC法)测定动物组织中恩诺沙星、环丙沙星的残留,具有很好的分离度,浓度5～500μg/mL呈良好的线性关系,R=0.99998;仪器检出限为5～10μg/mL;回收率范围为80.6%～99.7%;批内变异系数≤2.6%,批间变异系数≤7.6%。检测50批鸡肉中恩诺沙星、环丙沙星的残留,检出率为16.0%,检出的样品中,残留的量范围为9.04～79.7μg/kg,无超标现象。     

超高效液相色谱法检测饲料中氟喹诺酮类药物的方法研究

恩诺沙星、环丙沙星、沙拉沙星属于化学合成抗菌素类药物,在动物的饲料中添加会减少动物感染肠道类疾病的概率,但这类药物会残留在动物的肌肉组织中,人食用后给人体的健康带来不利影响,对生长发育中的儿童尤其不利,细菌耐药和不良反应也相继发生,主要有过敏、溢血、肾衰等。此外,还有诱发精神病及癫痫患者发病和增加致胎儿畸形的风险。文章以超高效液相色谱-荧光法检测饲料中的恩诺沙星、环丙沙星、沙拉沙星类违禁药物进行探讨,试样用磷酸盐缓冲溶液提取,C18萃取柱净化,流动相洗脱后,用超高效液相色谱-荧光检测器测定,激发波长280nm,发射波长450nm处测定其吸光度,同条件下测定恩诺沙星、环丙沙星、沙拉沙星药物标准品相对应的峰面积响应值,恩诺沙星、环丙沙星、沙拉沙星含量与吸光度值在一定浓度范围内成正比,试样与标准品比较定量。经试验:此方法具有操作简单,回收率稳定,检测时间短等优点;标准品峰面积响应值稳定,此方法在环丙沙星、恩诺沙星、沙拉沙星浓度范围在0.1~0.5μg/m L时,能够达到较好线性系数,符合检测时的相关要求;恩诺沙星相关系数r≥0.99996,环丙沙星相关系数r≥0.99987,沙拉沙星相关系数r≥0.99982。恩诺沙星回收率为:83.5%~96.5%,批内变异系数≤4.2%,批间变异系数≤7.5%;环丙沙星的回收率为:74.9%~95.5%,批内变异系数≤5.1%,批间变异系数≤7.7%;沙拉沙星回收率为:80.1%~95.0%,批内变异系数≤4.5%,批间变异系数≤6.5%。     

鸡组织中对羟基肉桂酸残留的UPLC检测方法研究

建立了鸡组织(肌肉、肝脏、肾脏)中对羟基肉桂酸(PCA)超高效液相色谱检测方法。组织样品用无水乙醚提取,提取液50℃氮气吹干,20%的甲醇溶液复溶,用0.22μm滤膜过滤。以C18为色谱柱,甲醇-1%乙酸溶液(20/80,v/v)为流动相,检测波长310 nm,流速0.3 mL/min,用超高效液相色谱检测。对羟基肉桂酸标准品工作液在5～400 ng/mL浓度范围内线性关系良好(r=0.9996);组织中药物添加浓度分别为20、50、100μg/kg时,其样品中药物平均回收率分别98.46%～103.66%、85.09%～107.15%和80.27%～97.63%;日内、日间变异系数均≤10%。在该检测条件下,PCA在鸡肌肉、肝脏、肾脏中检测限分别为1μg/kg、2μg/kg和1μg/kg。定量限分别为2μg/kg、4μg/kg和2μg/kg。该方法样品处理简单,且准确度和精密度均符合残留检测方法要求,可以作为对羟基肉桂酸在鸡组织内的残留检测方法。     

抗球虫新药癸氧喹酯在鸡体内的残留试验

建立了高效液相色谱-荧光法(HPLC-FLD)来检测肉鸡肌肉、肝脏、肾脏和皮肤/脂肪组织中癸氧喹酯的残留量。将癸氧喹酯以0.05,0.2,0.6μg/g的含量分别添加到空白组织中,测得肌肉、肝脏、肾脏和皮肤/脂肪组织的回收率大于75%,变异系数低于9%。用该方法测定肌肉、肝脏、肾脏和皮肤/脂肪组织中癸氧喹酯的最低检测限为0.01μg/g。试验鸡以30mg/L的癸氧喹酯的剂量连续7d饮水给药,停药后各组织中癸氧喹酯的残留量逐渐下降;停药第3天后肌肉中检测不到癸氧喹酯,停药后第5天所有组织中均检测不到残留药物。     

高效液相色谱-串联质谱法检测牛组织中双氯芬酸钠残留的研究

为了测定牛肌肉、肝脏、肾脏组织中双氯芬酸钠的残留量,研究建立了一种用于该检测的高效液相色谱-串联质谱(LC-MS/MS)方法。试验将样品中加入乙腈提取液重复提取2次,超声波辅助提取,提取液中加入C₁₈、PSA混合吸附剂进行净化。色谱柱采用C₁₈反相柱对药物进行分离,洗脱液采用乙腈-0.1%甲酸水进行等度洗脱,配备电喷雾离子源,药物在正离子模式下电离,多反应监测模式(MRM)分段扫描测定检测结果,并采用内标法定量分析。结果表明,双氯芬酸在0.5～100μg/L浓度范围内有良好的线性关系,相关系数大于0.99;在牛的肌肉、肝脏和肾脏组织中检测限(LOD,S/N=3)为0.5μg/kg,定量限(LOQ,S/N=10)为1.0μg/kg。在3个浓度添加水平下,平均回收率为97.7%～114%,日内变异系数0.5%～4.7%,日间变异系数为0.9%～7.5%。该方法操作简便、结果准确,满足兽药残留检测方法规定要求,运用于快速准确测定牛肌肉、肝脏、肾脏等组织中双氯芬酸钠的残留。     

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.     

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