凝胶渗透色谱净化-气相色谱分离同时测定饲料中30种有机磷农药残留

文中建立了凝胶渗透色谱净化-气相色谱法同时测定饲料中敌敌畏、乐果等30种有机磷农药残留的方法。饲料样品用乙腈体系提取,采用凝胶色谱柱净化,毛细管色谱柱分离(DB-50+,30 m×0.25 mm×0.25μm),火焰光度检测器(FPD)检测,外标法定量。其方法检测限为5.6~54μg/kg,三水平添加回收率为71.3%~114.1%,RSD为0.3%~14.8%。方法简便、准确,并能满足饲料中多种有机磷农残测定的需要。     

GC/MS法研究鸡蛋中三聚氰胺的残留

研究建立了GC/MS测定鸡蛋中三聚氰胺残留的方法。样品以10g/L三氯乙酸溶液提取,Cleanert PCX固相萃取柱净化,50℃水浴中氮气吹干后衍生化。以气相色谱-质谱选择99、171、327、342四个碎片离子进行定性定量分析。三聚氰胺在0.05mg/L～2.5mg/L成线性(R2为0.999),鸡蛋中3种不同添加浓度0.05、0.10和0.50mg/kg下三聚氰胺平均回收率分别为84.71%、88.12%、92.62%,相对标准偏差分别为10.57%、7.12%、6.92%,样品中最低检测限(S/N=3)为0.005mg/kg。     

液相色谱-串联质谱测定饲料中7种硝基咪唑类药物

采用液相色谱-串联质谱法(LC-MS/MS)测定了饲料中甲硝唑(MNZ)、地美硝唑(DMZ)、洛硝唑(RNZ)、替硝唑(TNZ)、奥硝唑(ONZ)、异丙硝唑(IPZ)和塞克硝唑(SCZ)等7种硝基咪唑类药物。样品用乙酸乙酯提取,正己烷-磷酸溶液反萃取,MCX柱净化,以0.1%乙酸水溶液和乙腈作流动相进行梯度洗脱,电喷雾电离源正离子(ESI+)多反应监测(MRM)模式下检测。方法的检测限和定量限分别为0.03 mg/kg和0.1 mg/kg。添加浓度为0.1、1 mg/kg和10 mg/kg时的平均回收率为72.9%~98.8%,变异系数为4.9%~12.1%。     

气相色谱法检测混合型饲料添加剂中的大蒜素和香芹酚

建立了检测混合型饲料添加剂中大蒜素和香芹酚含量的气相色谱方法。样品采用乙醇提取,经毛细管相色谱柱(HP-5,30m×0.32mm×0.25μm)分离,氢火焰离子化检测器测定,外标法定量,并采用气质确证。方法学研究结果表明,目标化合物二烯丙基二硫醚,二烯丙基三硫醚,香芹酚在0.01~10 mg/m L浓度范围内具有良好线性关系,相关系数为r≥0.9990,检出限分别为10mg/kg、15mg/kg、10mg/kg;回收率为79.8%~96.2%,相对标准偏差为2.61%~4.73%。该方法前处理简单,准确可靠,灵敏度可以用于混合型饲料添加剂样品中大蒜素和香芹酚进行测定。     

山西老陈醋醋糟中有机酸含量分析

试验采用离子色谱法测定了醋糟样品中乙酸、乳酸、苹果酸、酒石酸、α-酮戊二酸、亚油酸的含量;采用气相色谱法测定了醋糟样品中亚油酸的含量。结果:乙酸、乳酸、苹果酸、酒石酸、α-酮戊二酸、亚油酸在22个醋糟样品中的含量分别为0~7 528.25 mg/kg、46.79~3 731.69 mg/kg、0~2 097.81 mg/kg、97.66~521.12 mg/kg、0~6 894.55 mg/kg和0.35%~3.95%,变异系数分别是162.29%、63.55%、230.00%、38.98%、194.70%和40.62%。结果表明,醋糟中有机酸含量丰富,作为饲料原料使用可以补充日粮中的有机酸;不同醋糟样品之间有机酸含量差异较大,实际应用前应对不同批次样品进行测定。     

土壤中氟苯尼考及氟苯尼考胺高效液相色谱检测方法的研究

建立了土壤中氟苯尼考及氟苯尼考胺高效液相色谱(HPLC)检测方法。土壤样品采用超声提取法,提取试剂为丙酮和水,再与二氯甲烷进行液-液萃取净化杂质。Agilent SB-C18色谱柱进行分离后,光电二极管阵列检测器检测,流动相为磷酸二氢钠溶液(0.01 mol/L,含0.005 mol/L十二烷基硫酸钠,pH=4.4)和乙腈(V∶V=65∶35)。在0.025～5 mg/L浓度范围内,峰面积与浓度呈良好的线性关系,相关系数r均达0.999,氟苯尼考及氟苯尼考胺检测限分别为0.01、0.015 mg/kg,定量限分别为0.045、0.05 mg/kg。三种土壤中添加浓度为0.05、0.1、0.2 mg/kg时,氟苯尼考和氟苯尼考胺标准工作液的回收率分别为90.16%～99.37%、67.63%～96.86%,日内变异系数均≤7.83%,日间变异系数均≤10.52%。该方法高效快速,操作简单,成本低,可用于氟苯尼考及氟苯尼考胺的同时检测。     

气相色谱—质谱法测定饲料中四螨嗪的残留量

试验建立了气相色谱-质谱选择离子法(GC-MSD)测定饲料中四螨嗪残留量的检测方法。试样用水-丙酮(1 4)振荡提取,经二氯甲烷液-液分配,以凝胶色谱柱净化,再经氟罗里硅土(Florisil)固相柱净化,洗脱液浓缩并溶解定容后,供气相色谱-质谱仪检测,外标法定量。回收率范围为80.5%~99.0%;相对标准偏差为4.44%~9.64%;测定低限为0.010mg/kg。     

HPLC检测鸡组织中脱氢乙酸残留量的研究

为建立鸡组织(肌肉、肝脏、肾脏)中脱氢乙酸(DHA)残留的高效液相色谱(HPLC)检测方法,将鸡组织样品经乙腈提取,正己烷液-液萃取,PAX小柱固相萃取净化后,用乙腈溶解残渣,过滤,HPLC分析。色谱条件为:甲醇-0.02%乙酸铵缓冲溶液(20/80,v/v)为流动相,290nm紫外检测。DHA标准工作液在0.2~5.0mg/L浓度范围内线性关系良好(R2≥0.9996),方法检测限为0.1mg/kg,定量限为0.2mg/kg。各组织中DHA添加浓度为0.5、1.0、5.0mg/kg时,各组织样品中DHA回收率为68.28%~93.49%,日内变异系数在3.38%~7.94%,日间变异系数在4.31%~7.80%。所建立的HPLC方法能够满足动物性组织中DHA的残留检测,可为DHA在动物性食品中的残留消除、最高残留限量及休药期研究提供技术支持。     

QuEChERS/高效液相色谱串联质谱法测定渔业饲料中敌百虫、敌敌畏、蝇毒磷的含量

本文建立了一种简单、快速测定渔业饲料中敌百虫、敌敌畏、蝇毒磷的QuEChERS-液相色谱串联质谱分析方法。样品经酸化乙腈提取,C18与中性氧化铝净化后,采用HPLC-MS/MS选择反应监测(SRM)正离子模式测定进行定性、定量分析。结果表明:在2.0～200 ng/mL范围内,峰面积与浓度线性良好,相关系数均大于0.9992;方法的检出限(LOD)为2.0μg/kg,定量限(LOQ)为4.0μg/kg,检测结果的相对标准偏差为1.62%～8.68%(n=6),平均加标回收率82.3%～105.2%。该方法具有较高的重现性和选择性,适用于渔业饲料中敌百虫、敌敌畏、蝇毒磷的残留分析检测。     

气相色谱-质谱法检测乳与乳制品中20种邻苯二甲酸酯

建立了乳与乳制品中20种邻苯二甲酸酯气相色谱-质谱联用仪分析方法.样品用正己烷提取后,采用DB-5MS(30m×0.25mm,0.25μm)石英毛细管柱分离,在进样口温度280℃,传输线温度280℃,离子源温度230℃条件下20种邻苯二甲酸酯完全分离.该方法各组分的相关系数均大于0.9990,线性范围0～10μg/mL,样品加标回收率为80％～109％.邻苯二甲酸二异壬酯、邻苯二甲酸二异癸酯化合物检出限分别为1.0、0.5mg/kg,其他化合物均为0.05mg/kg.该方法具有简单易行,快速准确,灵敏度高等优点.     

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 -