Deposition and depletion of maduramicin residues in eggs after oral administration to laying hens determined by LC-MS

The coccidiostat maduramicin has been approved as a feed additive for chickens and turkeys, although it is prohibited for use in laying hens. In the present study, laying hens were divided into three groups and fed for 14 days with medicated feed containing maduramicin, at three different concentrations: 50, 100 and 500 µg kg^?1. Eggs were collected during treatment and for 26 days after the end of feeding with medicated feed. Maduramicin residues were found exclusively in egg yolk, with the highest concentration in egg yolk of 459 µg kg^?1 for the highest dose. The maximum concentration of maduramicin in whole egg was 16.6 µg kg^?1 for the group receiving feed containing the maximum permitted level of maduramicin in feed (50 µg kg^?1). The half-life of elimination of maduramicin, calculated for post-treatment days 1–10, was 6.5 days. Twelve days after drug administration, the concentration of the maduramicin in egg yolk for Group 3 (fed with 500 µg kg^?1 maduramicin) still exceeded 20 µg kg^?1, while the concentrations for Groups 1 and 2 were 1.2 and 2.7 µg kg^?1, respectively.     

Distribution and elimination of levamisole in eggs and tissues after oral administration to laying hens,determined by LC-MS/MS

Levamisole was administered to laying hens, and concentrations in eggs and tissues (thigh muscle, breast muscle, liver and kidney) were determined by a newly developed liquid chromatography tandem mass spectrometry method, which allowed trace level quantification of levamisole. The adopted analytical method showed good sensitivity, repeatability and percentage of recovery from spiked matrices. Maximum concentrations of levamisole were found on the first day after the administration (531.1 μg/kg in liver, 164.3 μg/kg in egg yolk, 130.7 μg/kg in kidney, 78.0 μg/kg in breast muscle, 70.7 μg/kg in thigh muscle and 64.0 μg/kg in egg white), after which there is a decline. The compound was rapidly eliminated from eggs, with a half-life of 1.3 days. Elimination appeared to be slower in thigh muscle (3.5 days), breast muscle (3.4 days) and liver (3.3 days). According to this experiment, the levamisole withdrawal periods calculated for eggs, liver, kidney, breast muscle and thigh muscle in laying hens were 14.1, 6.1, >4.0, 14.5 and 13.0 days, respectively. The longest time for levamisole residues to be completely released from tissues was seen in liver samples (37.4 days), followed by thigh muscle, breast muscle and kidney. Elimination from eggs was fastest (16.4 days for levamisole residues to drop below the method quantification limit).     

Deposition and depletion of decoquinate in eggs after administration of cross-contaminated feed

Decoquinate, a chemical coccidiostat used as a feed additive, can occur in eggs due to cross-contamination of feedstuffs for laying hens. An experiment was designed to assess the transfer of decoquinate to hen eggs and its distribution between egg yolk and egg white. Hens were given the feed containing decoquinate at a cross-contamination level (0.34 mg kg^–1) and collected eggs were analysed using an LC-MS/MS method. The plateau level was reached on the eighth day of the experiment and averaged 8.91 µg kg^–1, which is far below the maximum level established at 20 µg kg^–1 for whole eggs. Decoquinate was deposited mostly in egg yolks (26.2 µg kg^–1) and did not deplete completely during 14 days of administration of decoquinate-free feed. The results confirmed that administration of cross-contaminated feed is associated with very low risk of non-compliant residue levels of decoquinate in eggs.     

Determination and depletion of amoxicillin residues in eggs

Eggs were used to study the determination and depletion of amoxicillin (AMO) residues after oral dosing hens (25.0 mg kg^–1, 50.0 mg kg^–1 body weight), once daily for five days. A reverse-phase high-performance liquid chromatography with fluorescence detection (RP-HPLC-FLD) method was developed to determine AMO residues in albumen, yolk and whole egg. By using pre-column derivatisation, an improved liquid–liquid extraction procedure was developed for sample preparation. AMO were extracted from eggs with acetonitrile. The extract solution was extracted using saturated methylene chloride. The supernatant was reacted with salicylaldehyde under acidic and heating conditions. Limits of detection (LODs) were 1.2 ng g^–1 and limits of quantification (LOQs) were 3.9 ng g^–1 for AMO. Recoveries of AMO from samples fortified at levels of 5.0–125.0 ng g^–1 ranged from 79.1% to 88.5% in albumen, 78.6–83.6% in yolk and 78.3–85.1% in whole egg, with coefficients of variation of ≤7.3%. The maximum concentrations of AMO in albumen, yolk and whole egg were found to occur at 1.5, 2.5, 1.5 days after withdrawal of medication respectively. AMO was not detectable in albumen at 7.5 days after final administration of AMO, at 10.5–11.5 days in yolk and 10.5 days in whole egg after administration of two oral doses. The method was applied during the residue study of AMO in order to formulate a reasonable withdrawal period to ensure food safety.     

基于QuEChERS-气相色谱-串联质谱法测定鸡蛋中48种农药残留

目的建立基于QuEChERS前处理方法结合气相色谱-串联质谱测定鸡蛋中48种农药残留的检测方法。方法样品用1%乙酸乙腈、MgSO4和NaOAC混合盐包脱水提取,经MgSO4、PSA、GCB和C18混合净化管净化,净化液经氮吹浓缩后乙酸乙酯定容,利用气相色谱分离,MRM模式测定,内标校正,外标法定量。结果 48种农药在线性范围为5～100 ng/mL内关系良好, r2均在0.995以上。方法检出限在0.03～5.00μg/kg之间,方法定量限在0.12～17.00μg/kg之间。48种农药在5、10和50μg/kg 3个加标水平上,平均回收率在70%～120%的占比分别为97.92%、97.92%、95.83%。相对标准偏差(relative standard deviation, RSD, n=6)为2.12%～12.28%。结论该方法基本能够满足应用于实际样品的分析检测,较传统检测方法更加简便快捷,使用试剂少,灵敏度高。     

固相萃取-超高效液相色谱-串联质谱法测定鸡蛋中甲硝唑残留

目的 优化鸡蛋中甲硝唑残留的固相萃取-超高效液相色谱-串联质谱(SPE-UPLC-MS/MS)分析检测方法。方法 样品经乙酸乙酯提取后,用MCX固相萃取小柱净化,以C18色谱柱进行分离,以0.1% 甲酸水-0.1% 甲酸甲醇溶液为流动相,梯度洗脱分离,在电喷雾ESI离子源正离子模式下,采用质谱多反应监测(MRM)模式进行定性分析,以内标法进行定量分析。结果 方法检出限(LOD)和定量限(LOQ)分别为0.02 μg/kg和0.2 μg/kg。精密度较好,在1.00 μg/L~100.00 μg/L范围内,甲硝唑的质量浓度和峰面积呈现出良好的线性关系,其相关系数为0.9996。结论 本方法简单,准确,可靠,能满足兽药残留分析的要求。     

Assessing the depletion of lincomycin in feathers from treated broiler chickens: a comparison with the concentration of its residues in edible tissues

ABSTRACT

Lincomycin is the first antimicrobial agent described for the lincosamide class and it is commonly used for the treatment of infectious enteric and respiratory diseases in poultry. Maximum residue limits (MRLs) in edible tissues have been established for this antimicrobial, however, no regulation has been proposed yet for by-products that are not intended for direct human consumption. Feathers are a by-product from poultry farming that might be used as an ingredient for diets fed to other farm animal species. The presence of antimicrobial residues in them is not monitored in spite of the fact that several studies have proved that they can persist in feathers. Currently though, no evidence has been presented regarding the behaviour of lincomycin in this matrix. Hence, this work intended to assess the depletion of lincomycin residues in feathers of birds treated with therapeutic doses and compare them with those detected in muscle and liver samples. Samples were collected for several days after ceasing treatment from a group of broiler chickens treated with a 25% lincomycin formulation. Methanol and Florisil® columns were used to extract and retain the analyte, and samples were analysed using a triple quadrupole mass spectrometer (API 5500, AB SCIEX?). On day 1 after ceasing treatment, average concentrations of lincomycin detected in feather samples reached up to 8582 μg kg^?1 and by day 16, these had only declined by 63%, to an average of 3138 μg kg^?1. Lincomycin residues were detected in feathers at every sampling point, even after they were not detectable in edible tissues. Depletion time was 98 days for feathers, considering the LOQ established for the methodology as cut-off value for the calculations. Data showed that lincomycin is highly persistent in feathers, which may result in this matrix becoming a re-entry route for its residues into the food chain.     

基于QuEChERS的UHPLC-MS/MS同时检测鸡蛋中19种农药残留量

目的：构建一种同时、快速、高效的检测鸡蛋中多种农残方法。方法：将QuEChERS与UHPLC-MS/MS结合用于鸡蛋中19种农药残留量的检测。结果：所建方法的检出限（LOD）和定量限（LOQ）分别为（0.39±0.66）,（1.28±2.17） μg/kg;加标回收率为79.25%～102.14%,相对标准偏差均值（RSD）为9.34%～16.72%;除恶唑菌酮外,鸡蛋中其余18种农药的线性相关系数接近0.999。所测鸡蛋中鸡蛋中19种农残检出总频率为2.82%,农残问题主要涉及辛硫磷和毒死蜱,其检出频率分别为22%,15%,浓度范围分别为2.08～729.74,0.81～46.89 μg/kg。结论：所建方法准确可靠,符合相关检测要求;湖北省境内鸡蛋中农残检出频次低、安全隐患较小。     

Distribution of chloramphenicol to tissues,plasma and urine in pigs after oral intake of low doses

Toxic effects of chloramphenicol in humans caused the ban for its use in food-producing animals in the EU. A minimum required performance level (MRPL) was specified for chloramphenicol at 0.3 μg kg^–1 for various matrices, including urine. In 2012, residues of chloramphenicol were found in pig urine and muscle without signs of illegal use. Regarding its natural occurrence in straw, it was hypothesised that this might be the source, straw being compulsory for use as bedding material for pigs in Sweden. Therefore, we investigated if low daily doses of chloramphenicol (4, 40 and 400 μg/pig) given orally during 14 days could result in residues in pig tissues and urine. A dose-related increase of residues was found in muscle, plasma, kidney and urine (showing the highest levels), but no chloramphenicol was found in the liver. At the lowest dose, residues were below the MRPL in all tissues except in the urine. However, in the middle dose, residues were above the MRPL in all tissues except muscle, and at the highest dose in all matrices. This study proves that exposure of pigs to chloramphenicol in doses occurring naturally in straw could result in residues above the MRPL in plasma, kidney and especially urine.     

Depletion of florfenicol and florfenicol amine in eggs of laying hens and growing pullets after oral administration

ABSTRACT

In this study, we carried out two experiments to evaluate depletion of florfenicol (FF) and its metabolite florfenicol amine (FFA) in eggs from growing pullets and laying hens. Eggs were collected, and the egg white and yolk were separated. FF and FFA were analysed by liquid chromatography-tandem mass spectrometry. In the first experiment, 30 laying hens were given FF capsules at 50 mg/kg·bw^?1 daily for 5 d. FF + FFA was detectable in egg white (1,190 µg/kg) on day 1 of treatment and increased slowly thereafter. After treatment, the residues decreased rapidly and were not detected by day 11. In yolk, residues were detected at a lower concentration on day 1 and increased dramatically to 3308 µg/kg at the end of treatment. The residues remained steady over the next 4 days post-treatment, followed by a rapid drop. Residues were not detectable on day 15 post-treatment. In the second experiment, four groups (B1 through B4) of growing pullets were treated in the same manner for 25, 20, 15, and 10 days before egg primiparity. FF and FFA were not detectable in the eggs of group B1; however, they were detectable in egg whites and yolks of groups B2, B3, and B4. The highest total concentrations of FF and FFA detected in egg white and yolk of group B4 were 3,190 µg/kg and 3,214 µg/kg, respectively. Thereafter, concentrations decreased until no more residues were detected in egg whites or yolks on days 17 and 21 post-treatment, respectively. Therefore, drug treatment should be stopped at least 21 d before primiparity of growing pullets to guarantee food safety.     

Pentachlorophenol,polychlorodibenzodioxin and polychlorodibenzofuran in eggs from hens exposed to contaminated wood shavings

Laying hens may be exposed to pentachlorophenol (PCP) present in bedding materials derived from treated timber. As a result, this chemical and its contaminants or degradation products, such as polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs), may be present in eggs. The litter-to-eggs transfer and depletion of these compounds were studied in a flock of laying hens reared on contaminated wood shavings. PCP determination was carried out via high resolution gas chromatography coupled to low resolution mass spectrometry/mass spectrometry (HRGC–LRMS/MS); PCDDs and PCDFs were quantified by HRGC–HRMS (SIM). After substitution of the litter contaminated with PCDDs and PCDFs at an average of 50 pg WHO-TE g^?1 and with PCP at 15 µg g^?1, pooled eggs from six selected hens were sampled twice a month for the depletion study. At steady state, PCDDs and PCDFs showed a transfer ratio of 0.9; for PCP it was 0.03. PCP concentration in eggs (500 ng g^?1 whole weight) fell sharply the second week after exposure withdrawal; for PCDDs and PCDFs (47 pg WHO-TE g^?1 fat, at day 0), the overall TEQ half-life was estimated at an average of 3.8 weeks. Due to differences in toxicokinetics (a faster depletion), PCP does not appear to be a suitable marker of PCDD and PCDF violative levels. However, the prominent analytical contribution of H₇CCD and O₈CCD in the contamination profile may help to trace the source of contamination. Among congeners, 2,3,7,8 T₄CDF exhibited a different depletion pattern, indicating a possible mechanism of active transport.     

Transfer of pyrrolizidine alkaloids from various herbs to eggs and meat in laying hens

To investigate the potential transfer of pyrrolizidine alkaloids (PAs), laying hens were fed for 14 days with diets containing 0.5% of dried common ragwort, common groundsel, narrow-leaved ragwort or viper’s bugloss, or 0.1% of common heliotrope. This resulted in total PA levels in feed of respectively 5.5, 11.1, 53.1, 5.9 and 21.7 mg kg^–1, with varying composition. PAs were transferred to eggs, in particular yolk, with steady-state levels of respectively 12, 21, 216, 2 and 36 µg kg^–1. Overall transfer rates for the sum of PAs were estimated between 0.02% and 0.23%, depending on the type of PAs in the feed. In animals slaughtered shortly after the last exposure, levels in meat were slightly lower than those in eggs, levels in livers somewhat higher. When switched to clean feed, levels in eggs gradually decreased, but after 14 days were still above detection limits in the hens exposed to higher PA levels. Similar was the case for meat and especially kidneys and livers. It is concluded that the intake of PA containing herbs by laying hens may result in levels in eggs and meat that could be of concern for consumers, and as such should be avoided.     

Survey of 11 nitroimidazole residues in hen and duck eggs from the Irish market

A liquid chromatography–tandem mass spectrometry method, recently developed, validated and accredited, was used to screen for metronidazole, ronidazole dimetridazole ipronidazole, ternidazole, tinidazole, ornidazole carnidazole and three hydroxy metabolites (hydroxy-metronidazole, HMMNI and hydroxy-ipronidazole) in Irish retail egg samples. The method used had decision limits (CCα) in the range 0.33–1.26?µg?kg^?1 and detection capabilities (CCβ) ranging 0.56–2.15?µg?kg^?1 for all analytes. Internal standard-corrected recovery, calculated for the various analytes, ranged 87.2–106.2%, while the coefficient of variance, expressed as % CV, ranged 3.7–11.3%. The method was applied to 160 samples of caged, free range and organic hen and duck eggs available on the Irish retail market as well as two incurred proficiency test egg samples. No nitroimidazole residues were detected in the survey samples above the CCα and the results achieved for the two proficiency test samples were acceptable when compared with the assigned values.     

Excretion of tetracycline and chlortetracycline in eggs after oral medication of laying hens

After dosing laying hens orally with tetracycline (TC) through either drinking water (0.25 and 0.5 g/l for 5 days) or feed (300 and 600 ppm for 7 days), and chlortetracycline (CTC) through feed (600 ppm) residues were determined by an agar plate diffusion technique in cylinders with Bacillus cereus as test-organism, separately for albumen and for yolk. The sensitivity threshold was 0.07 micrograms/g in albumen and 0.15 micrograms/g in yolk for TC and 0.01 micrograms/g in albumen and 0.06 micrograms/g in yolk for CTC. Drug excretion via egg was 3-fold higher for TC than for CTC. The drug was excreted preferentially into the yolk (about 75% of the total amount) and the elimination period lasted between 6 and 11 days for TC and 9 days for CTC, after treatment. Tetracycline use in laying hens is discussed, taking into consideration the proposals presented by the joint FAO/WHO Expert Committee on Food Additives.     

Residues of sulfadiazine and doxycycline in egg matrices due to cross-contamination in the feed of laying hens and the possible correlation with physicochemical,pharmacokinetic and physiological parameters

In the poultry industry, the widespread use of veterinary drugs such as antimicrobial compounds may lead to the presence of residues in whole eggs, egg white and egg yolk. During this study, laying hens received experimental feed containing sulfadiazine or doxycycline at cross-contamination levels of 2.5%, 5% and 10% of the therapeutic concentration. Since the therapeutic dose is 250?mg?kg^?1 for both substances, cross-contamination concentrations in the feed of 6.25, 12.5 and 25?mg?kg^?1 were expected. Whole egg, egg white and egg yolk samples were collected during the treatment and depletion period and were analysed via liquid chromatography-tandem mass spectrometry. For both drugs, a plateau phase was reached within 3–5 days and residue concentrations were detected in all egg matrices. For the 10% cross-contamination group, residual sulfadiazine concentrations of 208, 299 and 60?µg?kg^?1 and residual doxycycline concentrations of 455, 332, 206?µg?kg^?1 were detected in whole egg, egg white and egg yolk on day 13 of the treatment period, respectively. Both sulfadiazine and doxycycline had higher concentrations in egg white than in egg yolk, but the egg white–egg yolk ratio was higher for sulfadiazine than for doxycycline. As neither drug is allowed in Belgium for use in laying hens, residues may pose food safety concerns.     

Distribution of semduramicin in hen eggs and tissues after administration of cross-contaminated feed

Semduramicin is an ionophore coccidiostat used in the poultry industry as a feed additive. Cross-contamination of feeds for non-target animals with semduramicin is unavoidable. However, it is not known whether undesirable residues of semduramicin may occur in food after cross-contaminated feed is administered to animals. The aim of the work was to determine the levels of semduramicin in hen eggs (yolks and albumen) and tissues (liver, muscle, spleen, gizzard, ovarian yolks and ovaries) after administration of feed contaminated with 0.27 mg kg^?1 of this coccidiostat. The residues were determined using LC-MS/MS. The distribution pattern confirmed the high lipophilicity of semduramicin. Residues were found mainly in egg yolks (28.8 µg kg^?1), ovarian yolks (19.5 µg kg^?1) and liver (2.57 µg kg^?1), while hens’ muscle was free from semduramicin (LOD = 0.1 µg kg^?1). Among edible tissues, the maximum level (2 µg kg^?1) was exceeded only in the liver.     

Survey of the anticoccidial feed additive nicarbazin (as dinitrocarbanilide residues) in poultry and eggs

A survey was carried out on the occurrence of dinitrocarbanilide (DNC), the marker residue for nicarbazin, in poultry produced in Ireland during 2002–2004. Liver (n?=?736) and breast muscle samples (n?=?342) were tested. DNC residues were found in 40 and 26% of liver and breast muscle samples at levels greater than 12.5 and 5?µg?kg^?1, respectively. DNC residues were found at >200?µg?kg^?1 in 12 and 0% of liver and muscle samples, respectively. Samples of breast muscle (n?=?217) imported from 11 countries were also tested for DNC residues. A lower incidence of DNC residues (6%) was found in imported breast muscle. Egg samples (n?=?546) were tested and DNC residues were found in nine samples, with levels ranging between 14 and 122?µg?kg^?1. Analysis of poultry, carried out as part of official food inspection in the period 2004–2006, indicated a reduction in the number of broiler liver samples containing DNC at >200?µg?kg^?1, to approximately 7%. Low levels of DNC residues continue to be found in <2% of egg samples.     

超高效液相色谱-串联质谱法测定禽蛋中去呋喃头孢噻呋残留

目的 建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定禽蛋中去呋喃头孢噻呋残留量的分析方法。方法样品用0.4%二硫赤藓醇溶液及14%碘乙酰胺溶液在室温条件下衍生化,用水饱和的正己烷除脂,经PRiME HLB固相萃取小柱净化浓缩,UPLC-MS/MS测定,采用电喷雾电离源正离子扫描,多反应监测(multiple reaction monitoring,MRM)模式检测,内标法进行定量分析。结果在2～100μg/L的质量浓度范围内,去呋喃头孢噻呋呈良好线性关系,相关系数(r²)为0.9988。样品中去呋喃头孢噻呋的检出限为1μg/kg,定量限为2μg/kg,在2、4、20μg/kg的添加浓度下的平均回收率为92.0%～99.9%,相对标准偏差(relative standard deviations,RSDs)均小于10%。结论本方法专属性强、灵敏度高,适用于禽蛋中的去呋喃头孢噻呋药物残留的检测。     

Improved microbial screening assay for the detection of quinolone residues in poultry and eggs

An improved microbiological screening assay is reported for the detection of quinolone residues in poultry muscle and eggs. The method was validated using fortified tissue samples and is the first microbial assay to effectively detect enrofloxacin, difloxacin, danofloxacin, as well as flumequine and oxolinic acid, at or below their EU maximum residue limits (MRL). The accuracy of the assay was shown by analysing incurred tissue samples containing residue levels around the MRL. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) quantification of the quinolone concentration in these samples showed that the test plate can be used semi-quantitatively, allowing the definition of an “action level” as an inhibition zone above which a sample can be considered “suspect”. The presented assay is a useful improvement or addition to existing screening systems.