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。     

脱氢醋酸钠在猪组织中的残留研究

旨在研究脱氢醋酸钠作为饲料防霉剂应用后在猪组织中的残留消除。选用33只健康杜长大三元杂交猪,200 mg/kg脱氢醋酸钠拌料饲喂1个月。分别于停药1～21 d的不同时间取肌肉、肝脏、肾脏和脂肪组织, HPLC法测定脱氢醋酸钠含量。结果表明,脱氢醋酸钠在猪肾脏和肝脏组织中的残留水平较高,肌肉次之,脂肪中最少。休药1 d时,猪肾脏、肝脏、肌肉和脂肪中的平均残留量分别为1.12 mg/kg、1.06 mg/kg、0.59 mg/kg和0.21 mg/kg;脱氢乙酸钠在组织中的含量低于定量限0.2 mg/kg水平所需要的休药时间分别为:肌肉6 d、肝脏11 d、肾脏13 d、脂肪1 d后。脱氢乙酸钠在猪不同组织中的残留消除半衰期分别为:肌肉6.7 d、肝脏7.2 d、肾脏9.1 d、脂肪5.4 d。上述结果显示,脱氢乙酸钠在猪组织中的残留消除相对较快,组织残留量均低于1.2 mg/kg。     

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。     

超高效液相色谱-串联质谱法测定猪牛组织中甲基盐霉素残留量

建立超高效液相色谱-串联质谱法测定猪牛组织中甲基盐霉素残留量。猪、牛组织中残留的甲基盐霉素,经乙腈溶液提取,硅胶固相萃取柱净化,超高效液相色谱-串联质谱法测定,外标法定量。甲基盐霉素在5 ng/mL～250 ng/mL的浓度范围内呈现良好的线性关系,甲基盐霉素在猪、牛肌肉、肝脏、肾脏、脂肪中的检测限均为2.5μg/kg,定量限均为5.0μg/kg,猪牛肌肉、肝脏、肾脏、脂肪中5.0 ng/g～100 ng/g添加浓度范围内的回收率均值为71.9%～88.4%,批内批间RSD值均<15%。     

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。     

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-串联质谱法检测猪可食性组织中加米霉素残留

为了建立一种可靠、灵敏的检测猪可食性组织中加米霉素残留量的高效液相色谱-串联质谱方法,本试验将猪组织(肌肉、肝脏、脂肪和肾脏)经绞碎、均质后,用乙腈提取,乙腈饱和正己烷去脂,固相萃取柱净化,Kinetex C18色谱柱梯度洗脱,在电喷雾正离子下以多反应监测模式检测,内标法定量。结果显示,该方法的检测限和定量限分别为3μg/kg和5μg/kg;加米霉素在5～1 000μg/kg浓度范围内,峰面积与浓度的线性关系良好;猪肌肉、肝脏和脂肪在5、50、100μg/kg和200μg/kg四个添加浓度的平均回收率为70.20%～90.75%,批间变异系数≤11.94%;猪肾脏在5、150、300μg/kg和600μg/kg四个添加浓度的平均回收率为66.69%～87.46%,批间变异系数≤9.95%。结果表明该方法灵敏、准确,可满足兽药残留检测的要求。     

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。     

金霉素和代谢物差向金霉素在肉鸡肌肉和肝脏中的残留分布

为了研究金霉素(CTC)、差向金霉素(ECTC)在肉鸡肌肉、肝脏中的残留分布情况,样品经提取液提取后过Oasis HLB SPE小柱净化,采用电喷雾正离子模式(ESI+)和多反应监测模式(MRM),用高效液相色谱-串联质谱仪检测;试验组鸡按体重以50 mg/(kg·d)剂量内服CTC,连续5 d,每天给药1次。结果表明:该方法测定肉鸡肌肉和肝脏中CTC检测限和定量限分别为5.0、10.0μg/kg。ECTC检测限和定量限分别为20.0、30.0μg/kg。CTC和ECTC在肉鸡肌肉中平均回收率分别在73.0%~95.20%和81.80%~101.60%,相对标准偏差(RSD)分别在8.85%~12.18%和2.05%~9.29%;在肉鸡肝脏中平均回收率分别在67.06%~90.80%和78.64%~106.98%,RSD分别在2.90%~8.88%和4.72%~9.48%;肉鸡肌肉和肝脏中CTC、代谢物ECTC的残留量分别在给药后第1、5 d时达到最高。肉鸡肝脏中ECTC的残留量约占总残留量的1/2。停药后CTC及其代谢物ECTC代谢缓慢,在停药第6 d时,仍能检测到CTC及其代谢物ECTC,但其残留量均低于最高残留限量(MRLs)。从保障食品安全方面考虑,建议我国将CTC和ECTC均作为金霉素的残留标示物进行监测。     

烯丙孕素口服液在猪体内的残留消除研究

本研究旨在分析烯丙孕素在猪体内的残留消除规律,为制定休药期提供依据。采集猪肝、肾、肌肉和脂肪样品,肝、肾样品经β-葡萄糖醛酸酶/芳基硫酸酯酶酶解,然后用乙腈提取(肌肉和脂肪样品直接用乙腈提取),乙腈饱和正己烷溶液除脂,氮吹后残渣用乙酸乙酯复溶,后用10%碳酸钠溶液净化进行LC-MS/MS分析,外标法定量。结果表明:在1~200ng·mL~(-1)浓度范围内,烯丙孕素具有良好的线性关系,相关系数大于0.999,方法的检测限为0.5μg·kg~(-1),定量限为1μg·kg~(-1);在1、100、200μg·kg~(-1)添加水平下,化合物的平均回收率在68.9%~78.9%,相对标准偏差均小于11%。试验猪按0.4mg·kg~(-1)剂量内服给药,每天1次,连续给药18d,经取材检测,休药6h后各组织中烯丙孕素残留量最高,休药后第5天脂肪中烯丙孕素残留量低于最大残留限量,肌肉、肾中残留量低于定量限,休药第10天所有组织中烯丙孕素残留量均低于定量限。休药后相同时间点猪组织中烯丙孕素残留量规律为肝肾脂肪肌肉;肝中烯丙孕素消除缓慢且消除时间最长。根据WT1.4软件按99%置信区间计算所得,建议母猪按0.4mg·kg~(-1)剂量内服给药,每天1次,连续18d,其休药期为9d。     

Tissue residues of ractopamine and urinary excretion of ractopamine and metabolites in animals treated for 7 days with dietary ractopamine

Ractopamine HCl is a beta-adrenergic leanness-enhancing agent recently approved for use in swine. Depletion of ractopamine in tissues, and elimination of ractopamine and its metabolites in urine, is of interest for the detection of off-label use. The objectives of this study were to measure the residues of ractopamine in livers and kidneys of cattle (n = 6), sheep (n = 6), and ducks (n = 9) after treatment with dietary ractopamine for seven (sheep, ducks) or eight (cattle) consecutive days and to measure the depletion of ractopamine from urine of cattle and sheep. Two cattle and sheep and three ducks were each slaughtered with withdrawal periods of 0, 3, and 7 d. Urine samples were collected daily from cattle and sheep. Tissue ractopamine concentrations were determined using the regulatory method (FDA approved) for ractopamine in swine tissues. Ractopamine residues in urine samples were measured before and after hydrolysis of conjugates. Analysis was performed with HPLC using fluorescence detection after liquid- (hydrolyzed samples) and(or) solid-phase extraction. No residues were detected in duck tissues. Liver residues in sheep averaged 24.0 and 2.6 ppb after 0- and 3-d withdrawal periods, respectively. Sheep liver residues after a 7-d withdrawal period were less than the limit of quantification (2.5 ppb). Sheep kidney residues were 65.1 and undetectable at 0- and at 3- and 7-d, withdrawal periods, respectively. Cattle liver residues were 9.3, 2.5, and undetectable after 0-, 3-, and 7-d withdrawal periods, respectively; kidney residues were 97.5, 3.4, and undetectable at the same respective withdrawal periods. Concentrations of parent ractopamine in sheep urine were 9.8+/-3.3 ppb on withdrawal d 0 and were below the LOQ (5 ppb) beyond the 2-d withdrawal period. After the hydrolysis of conjugates, ractopamine concentrations were 5,272+/-1,361 ppb on withdrawal d 0 and 178+/-78 ppb on withdrawal d 7. Ractopamine concentrations in cattle urine ranged from 164+/-61.7 ng/mL (withdrawal d 0) to below the LOQ (50 ppb) on withdrawal d 4. After the hydrolysis of conjugates in cattle urine, ractopamine concentrations were 4,129+/-2,351 ppb (withdrawal d 0) to below the LOQ (withdrawal d 6). These data indicate that after the hydrolysis of conjugates, ractopamine should be detectable in urine of sheep as long as 7 d after the last exposure to ractopamine and as long as 5 d after withdrawal in cattle.     

Effects of ractopamine on genetically obese and lean pigs

Twenty-eight genetically obese and 24 lean barrows (65.0 and 68.7 kg average BW, respectively) were allotted within genotype to a 16% CP corn-soybean meal basal diet or this basal diet + 20 ppm ractopamine (a phenethanolamine beta-adrenergic agonist) and allowed ad libitum access to feed for 48 d. Compared to lean pigs, obese pigs had lower ADG, gain to feed ratio, longissimus muscle area, predicted amount of muscle, and weights of trimmed loin and ham, ham lean, heart, spleen, kidney and gastrointestinal tract (P less than .05). Obese pigs also had shorter carcass but higher dressing percentage, backfat thickness, fat depth, fat area, untrimmed loin weight and fasting plasma urea N concentration (P less than .05). Dietary supplementation with 20 ppm ractopamine reduced daily feed intake and improved gain to feed ratio in both lean and obese pigs (P less than .05). Pigs fed ractopamine had shorter carcasses, less fat depth and fat area, smaller weights of stomach and colon plus rectum, but higher dressing percentages, longissimus muscle areas, weights of trimmed Boston butts, picnics and loins, ham lean and predicted amounts of muscle than pigs not fed ractopamine (P less than .05). Supplemental ractopamine had no effect on fasting plasma concentrations of urea N, nonesterified fatty acids, triglyceride or glucose (P greater than .05). No genotype x ractopamine interactions for the criteria described above were detected (P greater than .05). These results suggest that ractopamine will improve the efficiency of feed utilization and carcass leanness in swine with different propensities for body fat deposition.     

β-激动剂克伦特罗在猪肝脏和肌肉组织中的残留

本文报道用高效液相色谱法检测β 肾上腺素能激动剂（克伦特罗Ｃｌｅｎｂｕｔｅｒｏｌ）在猪肝脏和背最长肌中的残留量。在肥育猪日粮中添加３ｍｇ／ｋｇ克伦特罗,试验期３０天,停药０、１、２、３、４天屠宰取肝脏和肌肉样。组织经匀浆浓缩提取,色谱条件为：ＣＬＣ ＯＤＳ色谱柱;以２０ｍｍｏｌ／ＬＫＨ２ＰＯ４＋３０μｍｏｌ／ＬＥＤＴＡ（ｐＨ３．９）乙腈＝８２１８（Ｖ／Ｖ）为流动相;紫外检测波长为２４３ｎｍ。结果表明,克伦特罗最低检测限为２ｎｇ／ｇ。停药当天（０天）肝脏和肌肉组织残留量分别为２０８．５ｎｇ／ｇ和１０．０ｎｇ／ｇ。停药后残留量迅速下降,肌肉在停药后第２天即检测不出,而肝脏要到第４天才检测不出。     

恩诺沙星混悬液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(口服)混悬液在猪体内各组织中的残留消除规律.恩诺沙星(口服)混悬液,按每头猪10 mg/kg体重的剂量灌服给药,连续使用3 d之后,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/三乙胺一乙腈(82+18)溶解,微孔过滤,进行...     

Residues of Sulfadimidine/Sulfanilamide and Sulfamethoxypyridazine in Sheep Tissue

Following treatment of sheep with different sulfonamides, residues in kidney, liver, and muscle have been determined by microbiological and chemical methods. By the microbiological method residues could be detected in kidney until the third day after the combined treatment with sulfadimidine/sulfanilamide. Using the chemical method, residues of about 3.80 p.p.m. could be found that day in kidney, while the concentrations in liver and muscle were about 1.90 and 1.20 p.p.m., respectively. On the eighth day after the last treatment traces of the medicine could be found in kidney, liver and muscle by using the chemical method.Residues of sulfamethoxypyridazine could be detected micro-biologically in kidney the second day after the last administration of the drug. The concentration at that time in kidney, liver and muscle determined by chemical analyses was about 4.66, 2.45 and 1.23 p.p.m., respectively. Traces of sulfamethoxypyridazine in kidney, liver and muscle could also be detected on the eighth day after the last medication.Considering altered metabolic rates of sick animals and variations in excretion rates between individuals of the same species, as well as variation in size of the doses applied, a 10 day withdrawal period for sulfonamides is proposed.     

Determination of sulphachloropyrazine-diaveridine residues by high performance liquid chromatography in broiler edible tissues

Diaveridine (DVD) is used in combination with sulphachloropyrazine (SPZ) as an effective antibacterial agent and antiprotozoal agent, respectively, in humans and animals. To gain a better understanding of the metabolism of SPZ and DVD in the food-producing animals, a high performance liquid chromatography (HPLC) method to determine and quantify sulphachloropyrazine (SPZ) and diaveridine (DVD) suspension residues from broilers is reported. Thirty healthy chickens were orally administered with sulphachloropyrazine-diaveridine (SPZ-DVD) suspension in water of 300 mg/l (SPZ) per day for seven successive days. Six chickens per day were slaughtered at 0, 1, 3, 5 and 7 days after the last administration. This procedure permitted SPZ and DVD to be separated from muscle tissue, liver, kidneys and skin with fat after extraction with acetonitrile and acetone under slightly acidic conditions. From the detected residuals in different tissues, we found that SPZ was quickly eliminated in liver and muscle, and slowly eliminated in kidney and skin with fat. DVD was quickly eliminated in liver and slowly eliminated in kidney. The withdrawal period of SPZ was 3.26, 3.72, 4.39 and 5.43 days in muscle, liver, kidney and skin with fat, respectively. The withdrawal period of DVD was 4.77, 4.94, 6.74 and 4.58 days in muscle, liver, kidney and skin with fat, respectively. Therefore, the suggested withdrawal period for SPZ-DVD suspension should be 7 days after dosing for seven successive days.     

Detection of melengestrol acetate residues in plasma and edible tissues of heifers

The aim of this study was to gain knowledge of residue formation after the use of melengestrol acetate (MGA) as a growth-promoting agent. Two Holstein-Friesian heifers each received a daily dose through the feed of 0, 0.5 mg (2 heifers with and without withdrawal each), 1.5 mg or 5.0 mg MGA for 8 weeks. MGA residues in plasma were screened by enzyme immuno-assay (EIA). Concentrations in kidney, liver, and muscle were quantified by liquid-chromatography-mass spectrometry (LC-MS), and in fat by gas chromatography-mass spectrometry (GC-MS). MGA levels in plasma were 40, 128, and 280 ng/L, respectively. Residues accumulated in muscle and kidney (5-fold), liver (20-to-40-fold), and fat (200-fold). After administration of 1.5 mg per day the mean MGA concentration in fat was 29 micrograms/kg and thus violated USA regulations which specify a limit of 25 ppb. Therefore the labelled use of MGA (0.5 mg per day) has to be officially controlled.     

猪鸡组织中左旋咪唑残留的HPLC检测方法研究

建立了猪、鸡组织中左旋咪唑残留检测的高效液相色谱法。组织试样在碱性条件下先用乙酸乙酯提取,然后用0.1 mol/L盐酸反萃取,萃取的样液用混合型阳离子固相萃取小柱净化,采用C18(5μm,250 mm×4.6 mm i.d.)色谱柱,用高效液相色谱仪(带紫外检测器)在220 nm波长处测定,外标法定量。在此条件下,左旋咪唑的保留时间为12～14 min。左旋咪唑浓度在10～1 000μg/L时,与峰面积呈良好的线性关系,线性方程为y=196.37x+81.599(r=0.999 9)。结果表明,左旋咪唑在在猪、鸡的肌肉、脂肪和肾脏中的检测限为2μg/kg,定量限为5μg/kg;在猪、鸡的肝脏中的检测限为2μg/kg,定量限为10μg/kg。在添加不同浓度水平测定下,平均回收率在70%～110%,批内变异系数在10%以内,批间变异系数在15%以内。     

Residues of spinosad in the tissues of sheep after aerosol treatment of blowfly myiasis

OBJECTIVE: To measure the residues of spinosad and chlorhexidine in the tissues of sheep after treatment of blowfly strike. PROCEDURE: Fourteen sheep with natural myiasis and 12 with artificial infestations of Lucilia cuprina larvae had the wool removed over their infestations and were treated with an aerosol wound dressing containing spinosad and chlorhexidine. Sheep were killed up to 14 days after treatment and residues of the chemicals measured in tissues. RESULTS: Chlorhexidine was not detected in any tissue. Residues of spinosad were highest in fat, lowest in muscle and intermediate in liver and kidney. The highest residue detected was 0.2 mg/kg spinosad in perirenal fat 7 days after generous treatment of a sheep with a large fly strike. Residues of spinosad in fat peaked 3 to 7 days after treatment and 1 to 3 days after treatment in liver and kidney. CONCLUSION: These studies present a realistic worst-case in struck sheep and at the highest dose studied, equivalent to 5.8 mg spinosad per kg body weight, the maximum residue detected of 0.2 mg/kg in peri-renal fat was 20% of the Australian maximum residue limit. Muscle, liver and kidney residues of spinosad were also below the Australian maximum residue limits at all times.