用酶联免疫吸附法测定鸡肉、鸭肉中金刚烷胺药物残留

本实验用酶联免疫吸附法测定鸡肉、鸭肉中金刚烷胺药物残留量.实验结果表明,试剂盒灵敏度为0.27μg/L;方法最低检测限为0.5μg/kg;在添加浓度为0.5μg/kg、1.0μg/kg、1.5μg/kg的空白鸡肉、鸭肉中的回收率均在84％～112％之间;各添加浓度的批内、批间变异系数均小于12％,该方法具有较好的准确度...     

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%。     

超高效液相色谱-串联质谱法测定鸡组织中氯苯胍残留

研究建立了鸡组织中氯苯胍残留的超高效液相色谱-串联质谱检测方法。样品经酸化乙腈提取后,分别经中性氧化铝柱和HLB固相萃取柱净化,C₁₈柱分离,超高效液相色谱-串联质谱测定,外标法定量。氯苯胍在10 ng/mL～500 ng/mL的浓度范围内呈线性相关,相关系数为0.994以上。本方法对氯苯胍在鸡组织中的检测限为5μg/kg,定量限为10μg/kg;鸡肉、鸡肝和鸡肾在添加50μg/kg～200μg/kg浓度范围内,其回收率为76.7%～107.6%,鸡脂肪和鸡皮在添加100μg/kg～400μg/kg浓度范围内, 其回收率为81.2%～106.8%, 批内变异系数均在1.4%～19.5%之间,批间变异系数在2.5%～12.8%之间。本方法快速、灵敏、重现性好,各项技术指标均满足国内外相关法规要求,适用于鸡组织中氯苯胍的残留检测。     

鸡组织中氯霉素残留的气相色谱-微电子捕获检测方法研究

建立了鸡肌肉和鸡肝脏组织中氯霉素残留的气相色谱-微电子捕获检测方法。用乙酸乙酯提取样品中的药物，正己烷脱脂，乙酸乙酯液-液分配，氮气吹干后，用Sylon BFT衍生化，进配有微电子捕获检测器（μECD）的气相色谱仪测定，外标法定量。鸡肌肉组织在0．1、0．5、1．0μg／kg三个添加水平，平均回收率为90．2％～94．3％，日内变异系数在4．5％-11．6％之间，日间变异系数在7．8％～14．3％之间，检测限0．05μg/kg，定量限0．10μg/kg。鸡肝脏组织在0．2、0．5、1．0μg/kg三个添加水平，平均回收率为82．9％～90．8％，日内变异系数在7．0％～11．2％之间。日间变异系数在7．9％～14．5％之间，检测限0．10μg/kg，定量限0．20μg/kg。     

ELISA法测定牛奶和鸡肌肉中四环素类药物残留

以本实验室研制的四环素类药物多残留检测试剂盒为基础，建立了牛奶和鸡肉中四环素、土霉素、金霉素药和多西环素的ELISA检测方法。该方法对牛奶和鸡肉中四环素的检测限为7μg／L（μg／kg）左右。在牛奶和鸡肉中，4种四环素类药物100μg／L（μg／kg）浓度的添加回收率范围为43．6％～101．4％，批内变异系数小于25％，批间变异系数在30％以内。牛奶的临界值为39．5μg／L，鸡肉的临界值为35.3μg／kg。     

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。     

免疫亲和柱荧光光度法和高效液相色谱法测定饲料中黄曲霉毒素

利用免疫亲和柱荧光光度法和高效液相色谱法测定饲料中黄曲霉毒素。免疫亲和柱—荧光光度法测定饲料中的黄曲霉毒素的测定范围0～50μg/kg;线性相关系数0.99;检测灵敏度1μg/kg;变异系数<18%;回收率82%～120%;分析时间20min,不需要剧毒的黄曲霉毒素标准品。免疫亲和柱-高效液相色谱法测定可以分别定量地检测饲料中黄曲霉毒素B1,B2,G1,G2,在黄曲霉毒素B1为0～50μg/kg测定范围内其线性相关系数0.91;检测灵敏度1μg/kg;变异系数<10%;回收率81%～110%。     

超高效液相色谱-串联质谱法测定水产品中群勃龙残留方法研究

建立了牛奶中苯并咪唑类药物及代谢物残留的超高效液相色谱-串联质谱检测方法。水产样品经乙酸乙酯提取,C18固相萃取柱净化,采用超高效液相色谱-串联质谱多反应监测模式检测,外标法定量。不同基质中,群勃龙在2-100 ng/mL的浓度范围内呈现良好的线性相关,相关系数为0.994以上;本方法对群勃龙群勃龙在鱼、虾、鳖、蟹类产品中的检测限为0.5μg/kg,定量限为1μg/kg;在贝类产品中的检测限为1μg/kg,定量限2μg/kg;不同水产品的基质中添加1-10μg/kg浓度范围内,其回收率为74.2%-119%,批内变异系数在1.0%-9.0%之间,批间变异系数在0.3%-8.5%之间。本方法分析速度快,灵敏度高,重现性好,各项技术指标均满足国内外相关法规要求,可用于水产品中群勃龙的残留检测。     

超高效液相色谱法测定鸡蛋中苏丹红Ⅰ、Ⅱ、Ⅲ、Ⅳ的残留

建立了鸡蛋中苏丹红Ⅰ、Ⅱ、Ⅲ、Ⅳ残留测定的超高效液相色谱方法。样品经乙腈提取后,反相液相色谱分离测定,本方法的检测限为10μg/kg。四种苏丹红染料在浓度50-2000ng／mL范围内与峰面积呈线性相关。在空白鸡蛋中添加100～600μg／kg浓度下,四种苏丹红的平均回收率为80％～100％,批内变异系数在0．6％～2．8％（n=4）,批间变异系数在0．7％～6．1％（n=3）。结果表明,该法简单、灵敏、特异性强,适用于鸡蛋中苏丹红染料残留的测定。     

用HPLC法测定动物肌肉中的磺胺类药物

七种动物肌肉组织中残留的磺胺间甲氧嘧啶(SMM)、磺胺地索辛(SDM)、磺胺二甲氧嘧啶(SM2)、磺胺甲恶唑(SMZ)、磺胺喹恶啉(SQ)经乙腈提取,正己烷分配,再经碱性氧化铝SPE柱净化后,用高效液相色谱-紫外检测法测定。该方法的最低检测限为2μg/kg,最低检出限为10μg/kg,回收率为60％-110％,批内变异系数小于15％,批间变异系数小于20％。     

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