环丙沙星在肉仔鸡组织中残留的研究

用高效液相色谱法(HPLC)检测肉仔鸡肌肉、脂肪、皮肤、肾脏和肝脏组织中环丙沙星的残留。肉仔鸡肌肉、脂肪、皮肤、肾脏和肝脏组织经二氯甲烷溶液提取,提取液浓缩后用含内标物的水溶液溶解。以0 015mol/L四丁基溴化铵/乙腈(92/8,v/v)作流动相,用SymmetryC18柱(5μm,3 9mm×150mm),在激发波长280nm、发射波长455nm处,用荧光检测器检测。将环丙沙星以0 01、0 05和0 50mg/kg分别添加到空白组织中,测得肌肉、脂肪、皮肤、肾脏和肝脏组织的回收率分别为72 2%～77 9%、73 2%～79 6%、72 4%～77 1%、69 6%～76 5%和70 0%～77 8%,变异系数均低于11 1%。用该方法测定肌肉、脂肪、皮肤、肝脏和肾脏组织中环丙沙星的最低检测限均为0 003mg/kg。肉仔鸡分别用50mg/L和100mg/L盐酸环丙沙星水溶液连续混饮各7d(35～41日龄)后,各组织中环丙沙星残留消除缓慢。休药7d时,肌肉、脂肪组织中环丙沙星残留量均低于0 03mg/kg;休药9d时,皮肤组织中环丙沙星残留量均低于0 03mg/kg;休药12d时,肾脏、肝脏组织中环丙沙星残留量均低于0 03mg/kg,而肌肉、脂肪和皮肤组织中环丙沙星残留量均低于最低检测限(0 003mg/kg);且随着环丙沙星混饮浓度的增大,环丙沙星在各组织中的残留量也相应增大。     

盐酸沙拉沙星在鸡体内的药代动力学及残留的研究

为研究盐酸沙拉沙星在蛋鸡体内组织动力学与残留，选用成年健康蛋鸡95只进行试验。按10mg/kg体重口服给药，给药后定期采样，测定血清及心，肝，肾，肌肉中盐酸沙拉沙星的含量。结果表明：盐酸沙拉沙星在血液中经时过程符合一级吸收一室模型，主要动力学参数t1/2k3.793h,tmax1.5807h,cmax0.7429μg/ml,AUC5.3790μg/ml.h。心脏，肾脏符合一级吸收三项指数方程，主要动力学参数分别为t1/2B7.765h,40.26h,t1/2a1.6027h,4.418h,tmax1.6826h,1.9855h,cmax0.5129μg/ml,0.9090μg/ml,AUC9.0265,10.894μg/ml.hμg/ml.h。肝脏，肌肉符合一级吸收二项指数方程，主要动力学参数分别为t1/2k3.1587h,4.124h,tmax1.9764h,3.5679h,cmax3.737μg/ml,0.6956μg/ml,AUC31.354μg/ml.h,5.3269μg/ml.h。盐酸沙拉星在蛋鸡体内残留为7天。     

达氟沙星(Danofloxacin)在鸡体内的组织残留

建立了坞组织中达氟沙星(Danonoxacin)的高效液相色谱(HPLC)测定方法，并测定了鸡单次内服(每千克体重5mg)给药后组织中的达氟沙星残留特征。组织样品用含0．015mol／L H3PO4和0．015mol／L HClO4的水-甲醇(50:50)提取，50℃水浴酸性水解90min，离心后取上清液作HPLC检测。色谱枉为Hypersil BDSC18柱；荧光检测器检测，激发波长280nm，发射波长440nm；流动相为含0．015mol／L四丁基溴化铵的水-乙腈(905:95，组织检测时为915：85)混合物，85％磷酸调pH为3．0。血浆、肝脏、肾脏、肺脏、肌肉中达氟沙星的检测限为0．02mg／L或0．02Pg／g，血浆样品回收率大于90％，组织样品回收率均大于74％。鸡单次内服甲磺酸达氟沙星后，在60h内各组奴中均可检出药物，但在48h所有组织中药物残留量均低于相应的MRLs(最高残留限量)。结果表明，达氟沙星在鸡组织中消除相对较慢。     

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。     

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。     

阿莫西林在鸡组织中的残留消除规律

本试验旨在研究阿莫西林在鸡组织中残留消除规律。鸡组织样品经磷酸二氢钠溶液提取,乙腈去蛋白,正己烷去脂肪,饱和二氯甲烷萃取,上清液经水杨醛在酸性条件下沸水浴衍生化后,在激发波长358nm、发射波长440nm处用高效液相色谱荧光检测器检测。该方法测定鸡组织中阿莫西林的检测限为5μg/kg、定量限为13μg/kg。阿莫西林在鸡组织样品中平均回收率为73.64%~88.82%,相对标准差为6.21%~9.63%。各试验组京海黄鸡分别按体质量以30、60mg/kg剂量内服阿莫西林,每天1次,连续给药7d,休药4h后(零休药期)各组织中阿莫西林残留量最高,休药第3天各组织中阿莫西林残留量均迅速降低;休药后第5天阿莫西林残留量低于最高残留限量(50μg/kg);休药第9天所有组织中阿莫西林残留量均低于检测限;休药后相同时间点鸡肌肉中药物残留量最低,肝脏中的药物残留量最高;阿莫西林在鸡肾脏中残留比鸡肌肉、肝脏消除缓慢且消除时间长;阿莫西林在鸡组织中的残留量与给药剂量呈正相关。根据WT1.4软件计算所得,建议黄羽肉鸡按体质量以30、60mg/kg剂量给药,每天1次,连续7d后,其休药期(WT)分别为3、4d。     

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。     

恩诺沙星微囊制剂在猪体内残留消除规律研究

采用高效液相色谱法研究恩诺沙星微囊制剂在猪体内各组织中的残留消除规律。恩诺沙星微囊制剂混饲,连续给药7 d,宰杀猪,取组织。组织样品经磷酸盐缓冲液提取,C18固相萃取柱净化,过膜,用流动相:0.05 mol/L磷酸溶液/三乙胺-乙腈(82+18)溶解,微孔过滤,进行HPLC分析。结果表明,当样品浓度为0.02～1μg/g时,线性关系良好。该法最低检测限为20μg/kg,回收率在72%～90%之间,变异系数小于10%。残留在肌肉、脂肪中的恩诺沙星和环丙沙星消除较快,第5天总残留量已下降至检测限以下;肝和肾脏中的残留药物消除较缓慢,第7天肾中药物总残留量为91.48μg/kg。综合各组织中总残留量和MRL规定,建议恩诺沙星微囊制剂休药期为7 d。     

超高效液相色谱-串联质谱法测定鸡蛋中沙拉沙星残留的研究

建立了鸡蛋中沙拉沙星残留检测的液相色谱-串联质谱法。样品经1 mol/L磷酸和乙腈提取后,饱和正己烷除脂净化,以0.1%甲酸溶液和乙腈为流动相,液相色谱-串联质谱法测定,内标法定量。试验结果表明：沙拉沙星在1～25 ng/mL浓度范围内线性关系良好,相关系数r大于0.999。沙拉沙星在鸡全蛋及其蛋清、蛋黄中的检测限均为0.5μg/kg,定量限为1μg/kg。沙拉沙星在1、10、20μg/kg浓度添加水平内的平均回收率范围为97.0%～105.4%,批内、批间相对标准偏差在1.3%～10.3%范围之间。本方法适用于鸡全蛋及其蛋清、蛋黄中沙拉沙星残留量的测定。     

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 -