饲料中四环素类抗生素的放射免疫分析

本实验探讨应用放射免疫法检测饲料中四环素类抗生素残留,建立快速筛选方法,确定了样品处理及控制点设定的方法,用液相色谱质谱(LC-MS)法验证了放射免疫分析法筛选的样品,符合率达100%,且该方法特异性强,与氯霉素、红霉素、链霉素、青霉素G、磺胺嘧啶等其他抗生素无交叉反应。该法能达到检测饲料中四环素类抗生素残留的要求。     

牛奶中磺胺类抗生素的快速检测分析

建立牛奶中磺胺类抗生素残留检测的放射免疫方法。通过对磺胺嘧啶、磺胺甲基嘧啶、磺胺二甲基嘧啶、磺胺甲氧哒嗪、磺胺甲基异恶唑、磺胺间甲氧嘧啶、磺胺间二甲氧嘧啶和磺胺喹恶啉8种磺胺类药物在空白牛奶样品中的加标试验,确定该方法的筛选水平。结果发现,采用放射免疫法检测牛奶中的磺胺类抗生素,筛选水平可达到10μg/L,变异系数在1.79%￣5.56%之间;对8种磺胺类药物的混合标准溶液进行检测,100%可以被检测出,检测限达5μg/L。放射免疫法检测牛奶样品中的磺胺类抗生素,方法简便、快速,灵敏度和精确度能够达到检测要求。     

西安市售乳制品中抗菌药的残留检测

为了解西安市售消毒乳制品中抗菌药残留情况,以农业部2001年发布的无公害食品行业标准中牛乳不得检出抗菌药为判定标准,随机采购32份消毒牛奶,进行抗菌药残留检测。TTC法检测显示,抗菌药物残留阳性数为5份,阳性率为15.63%;ELISA法检测显示,磺胺二甲基嘧啶未检出,四环素类残留阳性数为3份,阳性率为9.38%,链霉素残留阳性数为7份,阳性率为21.88%。市售不同包装消毒牛奶中除新鲜屋包装外,其余均有抗菌药残留。进口消毒奶粉未检出抗菌药,检测国产消毒牛奶32份与国产奶粉20份,共检出阳性10份与11份,阳性率分别为31.25%和55%。通过检测可看出,奶粉中抗菌药残留阳性率显著比消毒牛奶高;包装精良的高档牛奶中抗菌药残留阳性率比普通包装牛奶低;进口消毒奶粉未检出抗菌药。检测结果显示抗菌药残留情况仍不容乐观。     

应用胶体金免疫层析法测定牛奶中的磺胺类药物残留

应用胶体金免疫层析法对牛奶中的磺胺类药物残留进行检测,研究该方法的灵敏度、假阳性率、假阴性率及特异性。结果表明,用胶体金免疫层析法测定牛奶中的磺胺类药物,检测限分别为磺胺嘧啶60μg/L、磺胺二甲基嘧啶20μg/L、磺胺喹噁啉80μg/L、磺胺氯哒嗪30μg/L、磺胺间二甲氧嘧啶50μg/L、磺胺间甲氧嘧啶50μg/L、磺胺甲噁唑80μg/L、磺胺苯酰50μg/L、磺胺对甲氧嘧啶30μg/L、磺胺异噁唑10μg/L、磺胺甲氧哒嗪70μg/L、磺胺多辛70μg/L,假阳性率为2%,假阴性率为0;方法的特异性较好,对其他抗生素无交叉反应;检测实际样本的结果与液相色谱-质谱/质谱法基本一致。可见,该方法简便、快速、准确、稳定,适用于牛奶中磺胺类药物残留的现场快速检测。     

HPLC法同时测定禽肉中氯羟吡啶和多种磺胺类药物残留

建立了用于禽肉中氯羟吡啶和磺胺嘧啶、磺胺甲基嘧啶、磺胺二甲基嘧啶、磺胺甲氧嘧啶、磺胺-6-甲氧嘧啶、磺胺甲基异噁唑、磺胺二甲氧嘧啶、磺胺喹噁啉等残留测定的高效液相色谱法。样品以乙腈-氯仿提取,正己烷脱脂净化,以Symmetry C18 5μm(4.6 mm×150 mm)色谱柱进行分离,二极管阵列检测器检测,梯度洗脱测定氯羟吡啶和8种磺胺。回收率在71.7%~99.7%,相对标准偏差为1.5%~3.8%,最低检测限除磺胺二甲氧嘧啶、磺胺喹噁啉为0.02 mg/kg外,其余都可达到0.01 mg/kg。该方法已成功应用于禽类样品多兽药残留的检测。     

高效液相色谱法测定奶粉中磺胺类药的物残留量的研究

磺胺类药物已广泛用于乳牛传染病的预防和治疗,而人们食用这种牛奶和奶粉后会影响体内核酸的合成,因而奶粉中残留有磺胺药物,会给人类健康造成一定危害。本文研究了奶粉中磺胺、磺胺嘧啶、磺胺二甲嘧     

TTC法检测牛奶中的抗菌药物

针对用TTC法检测牛奶抗菌药物残留过程中因为在被检乳样中加入指示菌的数量不稳定而影响检测的问题,本研究增设了菌液稀释度试验以确定加入的菌液量。同时,采用TTC法对奶牛场常用的几种抗菌药物检测其在乳中的最低检测浓度。结果是青霉素3μg/kg,链霉素660μg/kg,庆大霉素620μg/kg,卡那霉素6200μg/kg,红霉素30μg/kg,环丙沙星500μg/kg,土霉素100μg/kg,金霉素100μg/kg,磺胺嘧啶100μg/kg。本研究用TTC法对青霉素、红霉素、土霉素、金霉素和磺胺嘧啶的检测灵敏度均达到农业部规定的牛乳中兽药残留最高限量要求。TTC法具有简便、价廉的优点,并且所检测的抗菌素范围较广,符合我国奶牛场中使用抗菌药物种类较多的现状。     

戴尔沃牛奶广谱抗生素检测试剂盒在生鲜乳抗生素残留检测中的应用

为进一步从源头控制生鲜乳安全隐患,切实提高生鲜乳质量安全,农业农村部已经在全国范围内开展生鲜乳抗生素残留专项整治行动,同时生鲜乳中抗生素残留检测也是当前生鲜乳收购站及乳品企业在收奶过程中质量控制的重中之重。将戴尔沃牛奶广谱抗生素检测试剂盒运用到生鲜乳抗生素残留检测试验中,验证其对青霉素G、磺胺嘧啶两种抗生素的检测效果及灵敏度,同时对该试剂使用方法及注意事项进行介绍。     

奶与奶制品中兽药残留分析

为了解云南省牛奶中兽药残留情况,试验采用高压液相色谱（HPLC）分析法,在2003年6-12月份对市售牛奶中兽药残留现状进行了分析。结果：在所测定的18种兽药中,头孢氨苄、青霉素-V、磺胺二甲基嘧啶、氨苄西林、青霉素-G、磺胺嘧啶、磺胺甲嗯唑和环丙沙星8种药物的检出率（或超标率）均超过20％。在研究不同生产模式对牛奶中兽药残留的影响中发现,3种生产模式（合作社机械挤奶、规模化奶牛场机械挤奶、合作社手工挤奶）生产的原料奶中兽药残留量分别为231．57,457．64,187．33ng／mL,机械挤奶合作社生产的原料奶中兽药残留量显著高于规模化奶牛场和手工挤奶（P〈0．05）,后两者之间无显著差异（P〉0．05）。     

动物性食品中磺胺类药物残留检测方法的研究进展

动物性食品中兽药和饲料添加剂残留对人体健康所造成的危害,已经引起世界范围的广泛关注,成为人类亟待解决的问题之一。磺胺类药物特别是磺胺嘧啶、磺胺甲基嘧啶、磺胺二甲氧嘧啶、磺胺甲基异口恶唑等作为饲料添加剂或动物疫病治疗药物被广泛应用,然而不合理的用药导致磺胺类药物在动物性食品中残留,影响食品安全,进而危害人类健康。作者对目前动物性食品中磺胺类药物（SAs）残留的主要检测方法进行介绍,主要包括微生物检测法、分光光度计法、免疫分析法、色谱法及色/质联用技术等,重点介绍了免疫分析法和色谱法,并对各种检测方法做出评价及其发展趋势进行了展望。     

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 -