气相色谱/质谱法测定饲料中士的宁的研究

本实验建立了气相色谱/质谱法(GC/MS)测定饲料中士的宁的方法.试样用正戊烷除脂后,在碱性条件下,经乙醚提取,MCX固相萃取柱净化后,用GC/MS测定其中的士的宁.方法检测限和定量限分别为0.025 mg/kg和0.05 mg/kg;回收率为75.85%～105.65%,变异系数为6.76%～13.21%.本方法对饲料中士的宁残留量的检测分析准确可靠.     

ELISA方法检测猪尿中克伦特罗的方法验证

为了验证ELISA方法检测猪尿中克伦特罗残留量的可行性,采用ELISA方法对试剂盒的校正曲线的线性相关关系、检测限、重复性和样品加标回收率进行了验证.结果为,试剂盒的校正曲线的线性相关系数为0.985;定性检出限为0.147ng/mL,定量检出限为0.490ng/mL;添加0.5ng/mL、1.0ng/mL、5.0ng/mL的克伦特罗标准液时,变异系数分别为2.29%、6.97%、2.73%,平均回收率分别为91.8%、102.4%、99.7%.结果表明应用ELISA方法检测猪尿中克伦特罗残留量符合实验室质量控制规范的要求,适合检测猪尿中克伦特罗残留量的初筛.     

猪肾脏等组织中盐酸莱克多巴胺的HPLC检测方法及其残留消除

本研究建立了猪肝脏、肾脏、肌肉和脂肪中盐酸莱克多巴胺的高效液相色谱检测方法。方法的检测限为1ng/g,定量限为2 ng/g,肝脏的平均回收率在73.4%～83.2%,变异系数在2.1%～6.6%;肾脏的平均回收率在73.1%～95.5%,变异系数在3.8%～4.0%;肌肉的平均回收率在80.7%～82.5%,变异系数在4.9%～9.1%;脂肪的平均回收率在73.3%～78.8%,变异系数在2.9%～6.7%。对60头健康猪以18 mg/kg的剂量混饲给药28d,停药饲喂14 d。在给药7、142、8 d和停药1、2、3、7、9、14 d分别屠宰6头猪,取各组织进行残留量测定。结果显示：肾脏中残留量最高,肝脏其次,残留量在停药期间较给药期间显著降低。其中肾脏和肝脏中的残留量分别在停药14 d、停药9 d后降至定量限以下;肌肉和脂肪中的残留量显著低于肾脏和肝脏,给药28 d时,残留基本低于定量限;停药1 d时均低至检测限以下。     

应用ELISA方法检测猪尿中莱克多巴胺残留量

为了验证ELISA方法检测猪尿中莱克多巴胺残留量的可行性,采用ELISA方法对试剂盒的校正曲线、检测限、加标回收率试验等方面进行了验证。结果为试剂盒校正曲线的线性相关系数为0.9913;样品的定性检出限为0.087ng/mL,定量检出限为0.29ng/mL;添加1.1ng/mL、2.2ng/mL、4.4ng/mL、6.6ng/mL和11.0ng/mL的莱克多巴胺标准液时,变异系数分别为3.06%、8.55%、4.41%、9.92%、8.19%;平均回收率分别为93%、113%、103%、96%、91%。结果表明,应用ELISA方法检测猪尿中莱克多巴胺残留量符合要求,适合检测猪尿中莱克多巴胺残留量的初筛。     

高效液相色谱法测定动物肺脏中替米考星残留量

建立了动物(牛、猪、鸡)肺脏中替米考星残留量的高效液相色谱检测方法。样品用乙腈提取,C18固相萃取柱净化,紫外检测器290nm测定。空白动物肺脏中添加0.04、0.1、1.0、10.0mg/kg浓度的替米考星,方法的平均回收率在76.8%～94.1%之间,变异系数在2.7%～8.6%之间,检测限为0.01mg/kg,定量限为0.04mg/kg。该方法可以用于动物肺脏中替米考星残留量的测定。     

盐酸沃尼妙林预混剂在猪组织中残留消除规律研究

建立了猪肝脏、肾脏、肌肉和脂肪中盐酸沃尼妙林的高效液相色谱检测方法并研究盐酸沃尼妙林预混剂在猪体内各组织中的残留消除规律。对24头健康猪以200mg/kg的剂量混饲给药21d。在停药后0、6、12、18、24、36h分别宰杀4头猪,采集各组织进行药物残留测定。方法的检测限为0.025～0.062 5μg/g,定量限为0.05～0.1μg/g,肝脏的平均回收率为75.5%～76.4%,变异系数为2.3%～3.8%;肾脏的平均回收率为75.8%～78.5%,变异系数为4.1%～6.0%;肌肉的平均回收率为79.3%～80.0%,变异系数为3.0%～4.7%;脂肪的平均回收率为76.7%～77.3%,变异系数为3.3%～5.4%。结果表明,盐酸沃尼妙林在肝脏中残留量最高,肾脏其次;肌肉和脂肪中的残留量显著低于肝脏和肾脏,停药24h时,残留量低于定量限;停药36h时残留量均低至检测限以下。盐酸沃尼妙林预混剂在猪组织中消除迅速,建议休药期为2d。     

猪排泄物中恩诺沙星和环丙沙星含量的HPLC检测方法

为了对猪排泄物中恩诺沙星(enrofloxacin,ENR)和环丙沙星(ciprofloxacin,CIP)进行定量检测,试验建立了测定猪粪尿中ENR和CIP含量的高效液相－荧光检测方法。将猪粪经乙腈－氨水超声提取后,加入三氯乙酸酸化,然后分别将经磷酸酸化后的猪尿和提取后的猪粪溶液经固相萃取小柱富集净化,取净化液进行HPLC分析。HPLC流动相为乙腈(A):柠檬酸/乙酸铵缓冲液(B),梯度洗脱:0~25 min,A 10%~40%;25~30 min,A 40%至10%,荧光检测器的激发波长278 nm,发射波长465 nm。结果表明,ENR和CIP 在尿中的最低检测限(LOD)<0.01 mg/L,在粪中的LOD<0.021 mg/kg,在尿中的最低检测限(LOQ)<0.03 mg/L,在粪中LOQ<0.056 mg/kg,猪尿中的ENR和CIP在0.01~1.0 mg/mL范围内线性关系良好,R²分别为0.9994和0.9992;猪粪中的ENR和CIP在0.02~2.0 mg/mL范围内线性关系良好,R²分别为0.9986和0.9981。ENR在猪粪和猪尿中的回收率分别为79.4%和88.5%,CIP在猪粪和猪尿中的回收率分别为75.8%和89.9%。该方法样品处理简单,检测结果准确可靠,且灵敏度较高,是值得推广的检测方法。     

鸡猪排泄物中恩诺沙星和环丙沙星含量HPLC检测方法的建立

建立了测定鸡、猪排泄物中恩诺沙星及环丙沙星含量的高效液相-荧光检测方法.将猪粪和鸡粪尿混合物样品分别用甲醇氨水溶液和醋酸甲醇溶液浸提,猪尿用固相萃取小柱富集净化,流动相为乙腈-三乙胺磷酸溶液（0.02 mol/L）,荧光激发波长280 nm,发射波长450 nm.检测结果表明,排泄物样品中恩诺沙星和环丙沙星含量的检测定量限,鸡粪尿混合物为0.010 μg/g,猪尿0.005 μg/mL,猪粪为0.020 μg/g.外标法标准曲线的线性范围鸡粪尿混合物中恩诺沙星为0.010～100.000 μg/g、环丙沙星为0.010～50.000 μg/g,猪尿和猪粪中恩诺沙星和环丙沙星的线性范围分别为0.005～0.500 μg/mL和0.020～1.000 μg/g.恩诺沙星和环丙沙星的回收率分别大于75%和88%.HPLC方法的样品前处理和检测方法简便、快捷,准确性较微生物检测法高.     

恩诺沙星在猪组织中残留消除规律研究

在常规饲养条件下,对健康猪按2.5 mg/kg体重的剂量肌肉注射2.5%恩诺沙星注射液,每日2次,连续注射3 d.停药后第2、4、6、8、10、12、14天分别屠宰4头猪.分别采取每头猪的肌肉(注射部位)、脂肪(腹脂)、肝和肾脏等4种组织,用高效液相色谱法进行残留量测定.结果表明:残留在肌肉、脂肪组织中的药物消除较快,第8天总残留量(恩诺沙星 环丙沙星)已下降至检测限(20μg/kg)以下;肝和肾脏组织中的药物消除缓慢,第14天测得猪肾中药物总残留量为40μg/kg.     

饲料中九种磺胺药物的高效液相色谱测定

本研究建立了高效液相色谱法检测饲料中9种磺胺药物的方法.将样品经乙腈提取,碱性氧化铝柱净化后,用HPLC法测定其中磺胺类药物.方法检测限在0.3～0.5 mg/kg之间;回收率在87.6%～108.7%之间,变异系数为0.3%～8.7%.本方法对饲料中磺胺类药物的检测分析准确可靠.     

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.     

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