林可霉素在饲料中残留的微生物学检测方法

建立了林可霉素在配合饲料中残留的微生物学检测方法。样品用二氯甲烷提取经浓缩、溶剂转换．制成试样溶液，再用藤黄微球菌作为检定茼进行含量测定。结果显示。林可霉素在0．15-2．4μg／ml的浓度范围内具有良好线性关系（r=0．9991）。配合饲料中3种添加浓度1．00μg／g、400μg／g、8．00μg／g的平均回收率为80．2％（n=9）。RSD分别为5．7％、4．2％、2．2％（n=3）。     

鸡蛋中新霉素残留的微生物学检测方法

以表皮葡萄球菌26069型(Staphylococcus epidermidis,ATCC12228))为测试菌，用琼脂扩散法测定新霉素在鸡蛋中的残留。本方法的最低检测限为0．075μg／mL，标准曲线线性范围0．15～2．4μg／mL，相关系数为0．99997。鸡蛋中的最低检出限为0．25μg／g，可靠检出限0．5μg／g。在鸡蛋中添加新霉素0．5和1．0μg／g的回收率分别为78．6%和80．5%。本方法灵敏度和回收率高，操作简便，不需特殊设备，样品用量少，易于推广，适用于新霉素残留的定量分析。     

牛奶中残留的盐酸克伦特罗GC/MS测定

本文研究了牛奶中残留的盐酸克伦特罗的确证检测方法。残留的盐酸克伦特罗用乙腈、无水硫酸钠提取,提取液旋转蒸发干后,用pH5．2的乙酸胺缓冲液溶解。萃取的样液用C18和SCX小柱固相萃取净化,分离的残留药物经过双三甲基三氟乙酰胺（BSTFA）衍生后用带有质量选择检测器的气相色谱-质谱联用仪测定。该方法在0．005-0．2μg／mL内线性关系良好（r=0．999812）,3个浓度水平（0．005、0．01和0．02μg／mL）的平均回收率为70％～110％,变异系数为30％。     

鸡肝组织中磺胺类药物多残留分析法

建立了鸡肝组织中磺胺嘧啶、磺胺二甲基嘧啶、磺胺甲氧吡嗪、磺胺－6－甲氧嘧啶、磺胺甲恶唑、磺胺－2，6－二甲氧嘧啶和磺胺喹恶啉的多残留高效液相色谱分析法。样品经乙腈提取、正己烷液－液分配和碱性氧化铝柱固相萃取法净化后用反相高效液相色谱法测定（UV270nm）。7种磺胺类药物标准曲线的相关系数（r^2)为0．9991－1．0000（0.01μg/ml-0.5μg/ml）。在0.05mg/kg-0.5mg/kg浓度范围内，磺胺类药物的回收率为68．8％－100．0％，变异系数为1．3％－12．0％。 检测限为0．01mg/kg-0.03mg/kg，定量限低于0.05mg/kg。     

水产品中氨基糖苷类药物残留的高效液相色谱-串联质谱检测方法研究

建立了高效液相色谱一串联质谱方法测定水产品中链霉素、双氢链霉素、新霉素、庆大霉素和卡那霉素5种氨基糖苷类抗生素的检测方法。样品中的氨基糖苷类抗生素用磷酸缓冲溶液提取液提取后,经固相萃取进行净化,改进了前处理方法,并对液相和质谱的条件进行了优化。通过实际样品的添加回收试验,方法的定量下限（S／N=10）为10．0μg,／kg。三个添加水平分别为10．0、20．0和50．0μg／kg时,龙虾、鲴鱼的加标回收率均在60％一110％,日内相对标准偏差不超过15．0％。结果表明,该方法简单、灵敏、特异性强,适用于水产品中氨基糖苷类药物残留的检测和确证。     

肉鸡体内新霉素药物残留消除规律的研究

用每公斤饲料含140 m g 新霉素碱的添加水平饲喂3 周龄肉鸡14d,用以表皮葡萄球菌( Staphylococcus epiderm idisATCC12228) 为测试菌的微生物学杯碟法对肉鸡体内新霉素残留的消除规律进行了研究,新霉素主要残留在肾脏,休药期0、1 和3d 的平均残留量分别为1.10、0.78 和0.58μg/g 组织。肌肉、肝脏和脂肪组织中未检测出新霉素残留。     

莫能菌素和盐霉素在鸡组织中的残留分析方法研究

本文报道用高效液相色谱柱后衍生化检测肉鸡肌肉、肝脏和脂肪组织中莫能菌素和盐霉素的残留。肉鸡肌肉、肝脏和脂肪组织经异辛烷提取,用硅胶柱净化分离,洗脱液浓缩后用甲醇／水溶解。以甲醇／冰乙酸／水（943／30／30,v/v）作为流动相,香草醛为衍生剂,用RP－C18柱在可见波长520nm处检测。将莫能茵素和盐霉素分别以0．10,0．20,0．40和0．20,0．40,0．800644g/g分别添加到空白肉鸡组织中,测得莫能菌素和盐霉素在肌肉、肝脏和脂肪组织中的平均回收率分别为97．7％、91．1％、92．1％和94．1％、85．4％、90．7％,变异系数范围在2．7％－16．8％之间。用该方法测定肉鸡组织中莫能菌素和盐霉素残留的最低检测限分别为0．05μg/g0．1μg/g。     

猪组织中替米考星残留的高效液相色谱检测方法研究

用乙腈和磷酸二氢钾缓冲液提取猪组织中替米考星，固相萃取柱净化，甲醇-乙腈-乙酸铵洗脱，紫外检测器290nm处检测，建立了猪组织中替米考星残留的高效液相色谱检测方法。该方法检测肌肉、肝脏中替米考星的检测限分别为0．01和0．025μg／g；定量限分别为0．02和0．05μg／g。肌肉在0．02～2．0μg／g添加范围内，平均回收率在84．2％～96．6％之间，变异系数在5．0％～8．2％之间；肝脏在0．05～5．0μg／g添加范围内，平均回收率在82．0％～92．8％之间，变异系数在5．8％～11．3％之间。本方法检测限低，分析简便、准确，符合残留分析的要求。     

高效液相色谱法检测猪血浆和肌肉组织中的氨苄青霉素残留

用三氯乙酸沉淀猪血浆和肌肉中的蛋白质并提取氨苄青霉素，提取液加甲醛溶液水浴衍生30min，用带有荧光检测器的HPLC在激发波长（Ex）346nm、发射波长（Em）422nm条件下测定衍生物。本方法最低检测限为0．005μg／mL，最低定量限为0．01μg／mL，组织的回收率为74．40％，血浆的回收率为95．23％。血浆日内变异系数为0．10％±0．06％，日间变异系数为0．14％±0．04％；肌肉日内变异系数为0．4％±0．03％，日间变异系数为0．11％±0．03％。     

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。     

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