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1.
A study of the tissue depletion of eprinomectin (EPR) subcutaneously administered to cattle at a dose of 500 mg per kg of body weight was carried out. EPR concentrations were determined in muscle, liver, kidney, and fat. Twenty-four parasite-free cross cattle were treated with the EPR injectable oil formulation. Three treated animals (two males and one female) were selected randomly to be sacrificed at 1, 3, 7, 14, 21, 28, 42, and 56 days withdrawal after injection. EPR residue concentrations were determined using HPLC with fluorescence detection. Muscle samples showed the lowest EPR concentrations throughout the study period. The highest EPR concentrations at all sampling times were measured in liver tissue, indicating that liver is a target tissue for EPR. EPR concentrations in all of the tissues analyzed were below the accepted maximum residue limits recommended by the European Union at 8 days posttreatment.  相似文献   

2.
Residue depletion of tilmicosin in chicken tissues   总被引：3，自引：0，他引：3  
A high-performance liquid chromatography (HPLC) method with detection at 290 nm was modified and validated for the determination of tilmicosin residues in broiler chicken tissues. The limits of detection (LOD) of the method were 0.01 microg/g for muscle and 0.025 microg/g for liver and kidney. Average recoveries ranged from 80.4 to 88.3%. Relative standard deviation values ranged from 5.2 to 12.1%. Residue depletion of tilmicosin in broiler chickens was examined after dosing over a 5-day period by incorporation of the drug into drinking water at 37.5 and 75.0 mg/L. Tilmicosin concentrations in liver and kidney were highest on day 3 of medication and on day 5 in muscle, in both low- and high-dose groups. The residue levels in both groups were significantly higher in liver than in kidney or muscle. A minimum withdrawal time of 9 days was indicated for residue levels in muscle, liver, and kidney tissues below the maximum residue level (MRL).  相似文献   

3.
A study of the tissue depletion of florfenicol (FF) administered intramuscularly twice to swine at a dose rate of 20 mg per kg of body weight at 24 h intervals was carried out. Forty healthy cross swine were treated with the FF injection formulation. Five treated animals were selected randomly to be sacrificed at 1, 3, 6, 9, 12, 14, 17, and 21 days withdrawal. FF and florfenicol amine (FFa) residue concentrations in muscle, liver, and kidney were determined using high-performance liquid chromatography (HPLC) with photodiode array (PDA) detection at 225 nm. Liver samples showed the lowest FF and the highest FFa concentrations throughout the experiment period. However, the highest total concentrations of FF and FFa during the study were found in kidney, which indicated that kidney is the target tissue for FF. The sum of FF and FFa concentrations in all tissues analyzed was below the accepted maximum residue limits recommended by the Agriculture Ministry of People's Republic of China and the European Union at 8 days posttreatment.  相似文献   

4.
In this study, the residue depletion of nitrovin in chicken was studied after feeding the birds with dietary feeds containing 10 mg/kg of nitrovin for 7 consecutive days. Tissues (muscle, fat, kidney, and liver) and plasma were collected at different withdrawal periods and determined by a high-performance liquid chromatography-ultraviolet (HPLC-UV) method. The limit of detection for nitrovin in tissue and plasma samples was 0.1 ng/(g or mL), and the inter- and intrarecoveries from the blank fortified samples were in the range of 71.1-85.7%. At the withdrawal period of 0 days, the residue concentration of nitrovin in plasma was the highest (average of 84.98 ng/mL) compared to those in muscle, fat, liver, and kidney (average of 21.04, 61.18, 24.04, and 68.28 ng/g, respectively). At the withdrawal period of 28 days, the residue levels of nitrovin in muscle, fat, liver, and plasma were all higher than 1.0 ng/(g or mL) and the highest concentration was in liver (average of 5.8 ng/g). These data are in support of the ban of nitrovin as a feed additive in food-producing animals.  相似文献   

5.
Depletion of moxidectin tissue residues in sheep   总被引：1，自引：0，他引：1  
The pattern of tissue depletion of moxidectin (MXD) subcutaneously administered to sheep was characterized in this study. MXD concentration profiles were determined in muscle, fat, and liver and at the site of injection following administration of a formulation combining MXD (0.5% w/v) with a standard 6 in 1 clostridial vaccine. Thirty-five (35) parasite-free Lincoln sheep were treated with the MXD injectable formulation at a dose rate of 0.2 mg of MXD/kg of live weight, administered subcutaneously on the inner surface of the thigh. Treated animals were sacrificed in randomly selected groups of six sheep weekly from day 21 until day 49 post-treatment. Three nontreated animals were sacrificed to obtain blank tissue samples to validate the analytical methodology. MXD concentration profiles were determined by a validated HPLC analytical method using fluorescence detection. MXD has an adequate pattern of absorption, based on the low residual concentrations found in the injection site area at all sampling intervals. Muscle samples showed the lowest MXD concentrations throughout the study period. The highest MXD concentrations at all sampling times were measured in the adipose tissue, indicating that fat is a target tissue for MXD. MXD concentrations in all of the tissues analyzed were below the accepted maximum limit of residue at 21 days post-treatment.  相似文献   

6.
A high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection was developed for the detection of cefquinome (CEQ) residues in swine tissues. The limit of detection (LOD) of the method was 5 ng g(-1) for muscle and 10 ng g(-1) for fat, liver, and kidney. Mean recoveries of CEQ in all fortified samples at a concentration range of 20-500 ng g(-1) were 80.5-86.0% with coefficient of variation (CV) below 10.3%. Residue depletion study of CEQ in swine was conducted after five intramuscular injections at a dose of 2 mg kg(-1) of body weight with 24 h intervals. CEQ residue concentrations were detected in muscle, fat, liver, and kidney using the HPLC-UV method at 265 nm. The highest CEQ concentration was measured in kidney tissue during the study period, indicating that kidney was the target tissue for CEQ. CEQ concentrations in all examined tissues were below the accepted maximum residue limit (MRL) recommended by the Committee for Veterinary Medical Products of European Medical Evaluation Agency (EMEA) at 3 days post-treatment.  相似文献   

7.
A liquid chromatographic method was used to monitor a depletion study of carbadox (and its most important metabolite, desoxycarbadox) in young pigs fed carbadox-treated rations for 1 week. Carbadox was found in blood (20 ppb), blood serum (26 ppb), and muscle tissue 24 h after withdrawal from treated ration; residues were reduced to a trace (less than 2 ppb) in 48 h, and eliminated by 72 h. Desoxycarbadox, although not detected in blood, was found in muscle (17 ppb) 24 h after withdrawal; it was reduced to 9 ppb at 48 h and to a trace by 72 h. Although no carbadox was detected in liver 24 h after withdrawal, appreciable desoxycarbadox (125 ppb) was found in liver 24 h after withdrawal; it was reduced to 17 ppb at 48 h and to a trace by 72 h. Whereas only a trace of carbadox was found in kidney 24 h after withdrawal, 186 ppb desoxycarbadox was found in kidney at 24 h, 34 ppb at 48 h, and a trace at 72 h. No metabolite of carbadox other than desoxycarbadox was found in extracts of swine tissues during this medicated feed trial, and no metabolite was found in blood extracts by using the established methodology. The effect of tissue storage (aging) at -20 degrees C on levels of the drug and its metabolite was a modest alteration of residue levels. The inadvertent use of feed adulterated with furazolidone and initially medicated with chlortetracycline, sulfamethazine, and penicillin G, did not affect the uptake of carbadox in this depletion study or interfere with the analytical methodology.  相似文献   

8.
A paper disc method is described for determination of residual cephalexin (CEX) in chick tissues. A trichloroacetic acid extract of plasma and tissues is chromatographed on a macroreticular resin (Diaion HP-20) column to remove endogenous antibacterial substances interfering with the assay. The eluate is evaporated to dryness and the residue, dissolved in methanol-water (1 + 2), is subjected to a paper disc assay using Bacillus stearothermophilus var. calido-lactis C953 NIZO as a test organism. The detection limit was 0.0375 ppm in tissue; the average recovery of CEX ranged from 72.4% in skin to 90.4% in plasma. Water containing 200 or 500 mg/L of CEX was given ad libitum to 2-week-old chicks for 10 days; the highest levels of CEX were found in the kidney, and the lowest were found in muscle at 0 h of withdrawal. CEX disappeared from most tissues at 24 h after withdrawal except from skin of chicks given 500 mg/L. However, the drug was not detected in the skin at 48 h after withdrawal.  相似文献   

9.
A study was conducted to monitor the elimination of dimetridazole (DMZ) and its major metabolite 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI) in swine plasma and tissue, using a liquid chromatographic method with electrochemical detector sensitive to 0.5 ppb. The study consisted of 2 experiments. In the preliminary experiment, one young female piglet was fed medicated ration containing 125 ppm dimetridazole (DMZ) for 2 weeks, followed by a withdrawal period using regular ration for 5 days. Another, control, piglet was given regular diet throughout. Plasma concentrations of DMZ and its most important residue, HMMNI, were measured daily at 2 h after the morning feeding and, on days 8 and 15, several times during the day. The 2 h concentrations after 3 days loading ranged from 47 to 77 ppb for DMZ and 424 to 1081 ppb for HMMNI. A daily cycle in the plasma levels was seen for both substances. Upon withdrawal of medication, elimination of drug and metabolite was biexponential with a terminal half-life of 6.7 h. In the second experiment, 5 piglets were medicated as above and slaughtered 2, 6, 12, 25, and 49 h after withdrawal of the medication; the concentration of DMZ and HMMNI was measured in plasma, muscle, kidney, and liver. DMZ in the plasma amounted to 22 and 1.8 ppb at 2 and 6 h, while HMMNI declined from 535 ppb at 2 h to 0.75 ppb at 25 h. Most values for both substances found in muscle were close to those in the plasma; in kidney they amounted to 9-17% of the plasma levels.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
Nitroxynil is an anthelmintic used in the treatment of liver fluke. In this study, six dairy cows were treated during lactation with Trodax, a 34% solution containing nitroxynil as its N-ethylglucamine salt, indicated for the treatment of fascioliasis in cattle and sheep. Samples were collected twice daily for 16 days and later at weekly intervals up to 58 days post-treatment. Nitroxynil residues were extracted from milk samples using acetonitrile; magnesium sulfate and sodium chloride were added to induce liquid-liquid partitioning and purified by dispersive solid phase extraction for clean-up. Nitroxynil was determined by ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in negative ionization mode. The limit of detection (CCα) of the method is 0.24 μg/kg. Maximum concentration of nitroxynil in the samples was in the range of 688-1358 μg/kg, with levels persisting for 58 days in four of the six lactating cows. Incurred nitroxynil samples were treated with sulfatase and β-glucuronidase from Helix pomatia ; the results indicated the presence of glucuronide conjugates in samples at early withdrawal times. At later withdrawal times the concentration of free nitroxynil was lower than the concentration in the control samples, indicating potential degradation during enzymatic treatment.  相似文献   

11.
The objectives of this study were to determine total radioactive residues and chlorate residues in edible tissues of cattle administered at three levels of sodium [36Cl]chlorate over a 24-h period and slaughtered after a 24-h withdrawal period. Three sets of cattle, each consisting of a heifer and a steer, were intraruminally dosed with a total of 21, 42, or 63 mg of sodium [36Cl]chlorate/kg of body weight. To simulate a 24-h exposure, equal aliquots of the respective doses were administered to each animal at 0, 8, 16, and 24 h. Urine and feces were collected in 12-h increments for the duration of the 48-h study. At 24 h after the last chlorate exposure, cattle were slaughtered and edible tissues were collected. Urine and tissue samples were analyzed for total radioactive residues and for metabolites. Elimination of radioactivity in urine and feces equaled 20, 33, and 48% of the total dose for the low, medium, and high doses, respectively. Chlorate and chloride were the only radioactive chlorine species present in urine; the fraction of chlorate present as a percentage of the total urine radioactivity decreased with time regardless of the dose. Chloride was the major radioactive residue present in edible tissues, comprising over 98% of the tissue radioactivity for all animals. Chlorate concentrations in edible tissues ranged from nondetectable to an average of 0.41 ppm in skeletal muscle of the high-dosed animals. No evidence for the presence of chlorite was observed in any tissue. Results of this study suggest that further development of chlorate as a preharvest food safety tool merits consideration.  相似文献   

12.
Ractopamine hydrochloride is a beta-adrenergic leanness-enhancing agent approved for use in swine in the United States. Depletion of ractopamine and its metabolites from animal tissues, urine, and serum is of interest for the detection of illegal use. The objectives of this study were to measure the residues of ractopamine in swine incurred samples after treatment with dietary ractopamine for 28 consecutive days. An efficient and sensitive analytical method was developed for the detection of parent ractopamine and its metabolites in swine tissues, urine, and serum by HPLC-FLD. After extraction, enzymatic digestion, and solid-phase cleanup of the samples, ractopamine residues were determined by liquid chromatography (LC) with fluorescence detector. The limits of detection (LOD) for tissues, urine, and serum were 1 ng g(-1), 0.5 ng mL(-1), and 0.5 ng mL(-1), respectively. Recoveries ranged from 70.5 to 94.5% for samples fortified at 1-50 ng g(-1) or ng mL(-1). Sixty pigs were fed twice daily for 28 consecutive days with feeds containing 18 mg kg(-1) ractopamine HCl. The residue concentrations in urine, liver, and kidney were 650.06 ng mL(-1), 46.09 ng g(-1), and 169.27 ng g(-1), respectively, compared with those in muscle, fat, and serum (4.94 ng g(-1), 3.28 ng g(-1), and 7.48 ng mL(-1), respectively) at the feeding period of 7 days. The residue concentrations at withdrawal period of 0 days in all edible tissues were lower than tolerance values established by the FDA and MRL values listed by the JECFA. These data support the withdrawal time of 0 days established by the FDA for ractopamine used as feed additive in swine.  相似文献   

13.
The objective of this study was to establish a withdrawal period for flunixin in milk by quantifying 5-hydroxyflunixin, the marker residue, in bovine milk as a function of time, following intravenous treatment of lactating dairy cows with flunixin-N-methyl glucamine (Banamine or Finadyne). Lactating dairy cows were dosed on three consecutive days at 2.2 mg of flunixin free acid/kg of body weight/day. Milk was collected twice daily and assayed using a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) procedure. The method was validated at concentrations in the range 0.5-250 ppb. The concentrations for 5-hydroxyflunixin measured 12 h after the last administration of drug ranged from 1.56 to 40.6 ppb for all cows. Milk concentrations for 5-hydroxyflunixin were used to establish withdrawal periods of 36 h using guidelines established by the U.S. Food and Drug Administration/Center for Veterinary Medicine and 24 h using guidelines established by the European Medicinal Evaluation Agency/Committee on Veterinary Medicinal Products.  相似文献   

14.
Chickens were used to investigate plasma disposition of florfenicol after single intravenous (i.v.) and oral dose (20 mg kg-1 body weight) and to study residue depletion of florfenicol and its major metabolite florfenicol-amine after multiple oral doses (40 mg kg-1 body weight, daily for 3 days). Plasma and tissue samples were analyzed using a high-performance liquid chromatography (HPLC) method. After i.v. and oral administration, plasma concentration-time curves were best described by a two-compartment open model. The mean [ +/- standard deviation (SD)] elimination half-life (t1/2beta) of florfenicol in plasma was 7.90 +/- 0.48 and 8.34 +/- 0.64 h after i.v. and oral administration, respectively. The maximum plasma concentration was 10.23 +/- 1.67 microg mL-1, and the interval from oral administration until maximal concentration was 0.63 +/- 0.07 h. Oral bioavailability was found to be 87 +/- 16%. Florfenicol was converted to florfenicol-amine. After multiple oral dose (40 mg kg-1 body weight, daily for 3 days), in kidney and liver, concentrations of florfenicol (119.34 +/- 31.81 and 817.34 +/- 91.65 microg kg-1, respectively) and florfenicol-amine (60.67 +/- 13.05 and 48.50 +/- 13.07 microg kg-1, respectively) persisted for 7 days. The prolonged presence of residues of florfenicol and florfenicol-amine in edible tissues can play an important role in human food safety, because the compounds could give rise to a possible health risk. A withdrawal time of 6 days was necessary to ensure that the residues of florfenicol were less than the maximal residue limits or tolerance established by the European Union.  相似文献   

15.
A gas chromatography-mass spectrometry method was developed to measure the stereochemical residues of clenbuterol derivatives in edible tissues of swine. Clenbuterol present in tissue extracts was derivatized with phosgene to form clenbuterol oxazolidin-3-one, which was then separated into component enantiomers using a dimethyl beta-cyclodextrin capillary gas chromatographic column. Purified clenbuterol stereoisomers, isolated using published liquid chromatographic techniques, were used to determine stereoisomer elution order, stereoisomer racemization potential, and accuracy of the method. The stereochemical composition of clenbuterol could be measured at tissue concentrations of <2 ppb using the method. The dextrorotatory stereoisomer was the predominant clenbuterol stereoisomer present in edible tissues of hogs slaughtered after withdrawal periods of 0, 3, and 7 days, with a (+)/(-) isomer ratio of about 3:1. The prevalence of the dextrorotatory stereoisomer in edible tissues of hogs at all withdrawal periods suggests that stereoselective processes are occurring during the absorption, distribution, metabolism, and (or) excretion of clenbuterol. The effect of clenbuterol dose on its stereochemical composition in edible tissues is unknown but will be an area of further investigation.  相似文献   

16.
《Applied soil ecology》2007,35(3):546-552
Fresh dung was collected from untreated cattle and cattle dosed with a spray-on formulation of high cis-cypermethrin and chlorpyrifos (2.1 g/cow), on days 1, 3, 5 and 7 post-treatment. The survival and reproduction of the dung beetle Copris tripartitus Waterhouse, when given this dung was assessed. Residues of high cis-cypermethrin and chlorpyrifos in dung collected 1 day after treatment were sufficient to inhibit oviposition by female C. tripartitus. However, there was no significant effect on egg-laying in dung collected at days 3, 5 or 7 days post-treatment. In a second generation of C. tripartitus, derived from beetles fed the dung from treated animals, residues in dung collected both 1 and 3 days after treatment were sufficient to inhibit oviposition, and residues in dung collected 1 day after treatment inhibited dung consumption by newly emerged adults of C. tripartitus. It is concluded that dung voided by cattle treated with a spray-on formulation of high cis-cypermethrin and chlorpyrifos have toxic lethal effects for 1 day post-treatment and sub-lethal toxic effects on ovarian condition and brood-ball production in dung voided at 1 and 3 days post-treatment. The potential ecotoxic effects of these compounds are discussed in terms of dung beetle activity and strategies for parasite control of cattle in the Korean environment.  相似文献   

17.
A method has been developed for determining ivermectin in 5 mL samples of cattle blood by a 2-step process: cleanup solvent extraction followed by direct injection onto a normal phase liquid chromatography (LC) system with UV detection. Recovery was 77-80% +/- 5.5% standard deviation. Endogenous interference that may be present caused the lower limit of detection to be set at 4-5 ng/mL. The method was used to show that in blood the distribution of ivermectin favors plasma in a fixed proportion over cellular material, and further to provide a time-course profile of ivermectin in the whole blood of injected cattle. In whole blood, ivermectin concentration peaked between 3 and 5 days and dissipated slowly with a half-life of 3 days.  相似文献   

18.
Monoclonal antibodies (Mabs) were developed that specifically bind tilmicosin. Keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA) conjugates were used for the immunogen and plate coating antigen, respectively. The conjugates were synthesized by different methods, resulting in different linkages. Six hybridoma cell lines were isolated that produced Mabs that competed with tilmicosin, and have IgG1 isotype. The Til-1 and Til-5 Mabs had IC50 values for tilmicosin of 9.6 and 6.4 ng/well (48 and 32 ng/mL), respectively, and limits of detection at IC20 of 1.84 and 0.89 ng/well (9.2 and 4.45 ng/mL), respectively. The Mabs demonstrated high cross-reactivity to the macrolides containing 3,5-dimethylpiperidine at C20 and the amino sugar at C5. No cross-reactivity was observed for tylosin and other macrolides that did not contain 3,5-dimethylpiperidine. A competitive enzyme-linked immunosorbent assay (ELISA) was developed for the antibiotic tilmicosin by use of the developed Mabs. These Mabs may be excellent candidates for the determination and immunolocalization of tilmicosin.  相似文献   

19.
2,4-Dichlorophenoxyacetic acid (2,4-D) labeled with (14)C was found to be rapidly eliminated by laying hens and lactating goats dosed orally for 7 consecutive days at 18 mg/kg of food intake and for 3 consecutive days at 483 mg/kg of food intake, respectively. Excreta of hens and goats contained >90% of the total dose within 24 h after the final dose. Tissue residues were low and accounted for <0.1% of the dose in these animals. For hens, the residues in muscle, liver, and eggs (0.006-0.030 ppm) were lower than those found in fat and kidney (0.028-0.714 ppm), 2,4-D equivalents. The tissue with highest residue in goat was the kidney at 1.44 ppm, 2,4-D equivalents. Milk, liver, composite fat, and composite muscle had significantly lower residue levels of 0.202, 0.224, 0.088, and 0.037 ppm, respectively. The most abundant tissue residue was 2,4-D and acid/base releasable residues of 2,4-D. A minor metabolite was identified as 2,4-dichlorophenol.  相似文献   

20.
Zilpaterol is a beta-adrenergic growth promoter approved in Mexico and South Africa for use in cattle. Understanding the rates of zilpaterol depletion from tissues and urine is of interest for the development of strategies to detect the off-label use of zilpaterol. Eight sheep were fed 0.15 mg/kg/day dietary zilpaterol hydrochloride (Zilmax) for 10 consecutive days; two sheep each were slaughtered 0, 2, 5, and 9 days after discontinuation of exposure to the zilpaterol-containing diet. Tissue zilpaterol levels rapidly decreased during the withdrawal period. On the basis of LC-MS/MS-ES (external standard) measurements, liver zilpaterol residues in sheep were 29.3, 1.5, 0.13, and 0.10 ng/g after 0, 2, 5, and 9 day withdrawal periods, respectively; kidney residues were 29.6, 1.10, and 0.09 ng/g and below the detection limit; and muscle residues were 13.3, 0.86, 0.12, and 0.08 ng/g at the same respective withdrawal periods. Between-animal variation in urinary zilpaterol concentrations during the feeding period was considerable, although zilpaterol concentrations converged somewhat as steady state was reached. During the first 3 days of the withdrawal period, zilpaterol elimination followed a first-order excretion pattern, having an average elimination half-life of 15.3 +/- 1.8 h. Urinary zilpaterol concentrations during the withdrawal period were determined using ELISA, HPLC-fluorescence, LC-MS/MS-ES (external standard), and LC-MS/MS-IS (internal standard). Comparison of these methods showed a high correlation with each other. With the exception of LC-MS/MS-IS, the regression coefficients of the linear equations with a zero intercept were between 0.90 and 1.25, indicating the near equivalence of the methods. Because of its simplicity, ELISA is a convenient assay for determining zilpaterol levels in urine giving similar results to HPLC-fluorescence and LC-MS/MS-ES without requiring the extensive cleanup of the latter methods.  相似文献   

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