Quantitative analysis of lincomycin and narasin in poultry, milk and eggs by liquid chromatography-tandem mass spectrometry

This study presents the simultaneous extraction and determination of lincomycin (LCM) and narasin (NAR) by using liquid chromatography-electrospray ionisation tandem mass spectrometry (LC-MS/MS) on samples from poultry, milk and eggs (n = 196). The homogenised samples are extracted with acetonitrile and the extract is further cleaned using C₁₈ solid-phase extraction cartridges. The recoveries of the analytes in different matrices were found ranging from 90% to 101% and 85% to 95% for LCM and NAR, respectively. The corresponding limits of detection were 0.6 and 1.5 ng g⁻¹ for LCM and NAR, respectively. As a result of monitoring, NAR was not detected in any samples and LCM was detected in one egg with a concentration of 25 ng g⁻¹. The method was relatively simple to perform and therefore could be used for food safety surveillance activities.     

Impact of feed supplementation with different omega-3 rich microalgae species on enrichment of eggs of laying hens

Four different omega-3 rich autotrophic microalgae, Phaeodactylum tricornutum, Nannochloropsis oculata, Isochrysis galbana and Chlorella fusca, were supplemented to the diet of laying hens in order to increase the level of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) in egg yolk. The microalgae were supplemented in two doses: 125 mg and 250 mg extra n-3 PUFA per 100 g feed. Supplementing these microalgae resulted in increased but different n-3 LC-PUFA levels in egg yolk, mainly docosahexaenoic acid enrichment. Only supplementation of Chlorella gave rise to mainly α-linolenic acid enrichment. The highest efficiency of n-3 LC-PUFA enrichment was obtained by supplementation of Phaeodactylum and Isochrysis. Furthermore, yolk colour shifted from yellow to a more intense red colour with supplementation of Phaeodactylum, Nannochloropsis and Isochrysis, due to transfer of carotenoids from microalgae to eggs.     

Measurement of ampicillin residue levels in chicken eggs during and after medicated feed administration by LC-MS/MS

A simple and sensitive LC-MS/MS method was developed and validated for the determination of ampicillin (ABPC) in chicken eggs. Residues were extracted by reverse-phase solid-phase extraction. Chromatographic separation was performed using a reverse-phase column with an elution gradient. The limits of detection and quantification were 0.01 and 0.1 ng g^?1, respectively. For the 0.1–50 ng g^?1 concentration range, mean recovery and accuracy values were 93.9–98.5% and 100.2–118.0%, respectively. ABPC residue concentrations in eggs before, during and after 7 days of medicated feeding of maximum dosage (40 mg kg^?1 body weight day^?1) of ABPC were determined with the LC-MS/MS method. The maximum concentration of ABPC in eggs was 3.6 ± 1.7 ng g^?1 (mean ± SD) on the last day of the administration period. Residue concentrations of ABPC in eggs during and after ABPC administration were not over the Japanese maximum residue limit of 0.01 mg kg^?1.     

Aflatoxin B1 residues in eggs of laying hens fed a diet containing different levels of the mycotoxin.

The present study was carried out to evaluate the excretion of aflatoxin B1 residues in eggs of young laying hens fed aflatoxin B1-contaminated rations for 8 weeks. To this end, 96 twenty-week-old hens were randomly distributed into four experimental groups (24 birds per group) and given rations containing either 0 (controls), 100 micrograms, 300 micrograms or 500 micrograms aflatoxin B1/kg feed. Egg aflatoxin B1 residues were determined by thin layer chromatography; two samples per treatment per week were used for analysis. Egg production and average egg weights were not affected (p < 0.05) in the groups receiving aflatoxin B1-contaminated rations. Residues of aflatoxin B1 were detected only in the eggs of hens given 500 micrograms/kg feed, at levels that ranged from 0.05 to 0.16 microgram/kg (average: 0.10 microgram/kg). The results indicate that the feed to eggs aflatoxin B1 transmission ratio was approximately 5000:1, emphasizing the importance of controlling aflatoxin levels in rations for laying hens.     

Determination of 14C residue in eggs of laying hens administered orally with [14C] sulfaquinoxaline

Ten layer hens were dosed for 5 consecutive days with 6.2 mg kg^-1 [¹⁴C] sulfaquinoxaline (SQX). Eggs were collected from the hens during the 5-day dosing period and during a 10-day post-dose withdrawal period. Egg yolk and albumen were separated and assayed for total radioactive residues (TRR) using a combustion oxidizer and liquid scintillation counting techniques. Significant amounts of radioactivity were detected on the second day of dosing (greater than 24 h after the initial dose) in both egg yolk and albumen. First eggs were collected about 8 h after dosing; the second-day eggs were collected during 8-h period after the second dose. Radioactive residues reached a maximum on the fifth day of dosing in albumen, whereas on the second day of withdrawal in egg yolk, the peak TRR levels in albumen were about threefold higher than in yolk. Thereafter, the TRR levels declined rapidly in albumen and were detectable up to withdrawal day 6, whereas the TRR levels in egg yolk declined more slowly and were detectable up to withdrawal day 10. High-performance liquid chromatography analysis indicated that the parent drug sulfaquinoxaline was the major component in both the egg albumen and yolk. Additionally, this work suggests that egg yolk is the appropriate matrix for monitoring SQX residues     

Fatty acid profile and sensory characteristics of table eggs from laying hens fed hempseed and hempseed oil

Hempseed (HS) is rich in omega-3 polyunsaturated fatty acids, with approximately 17% of total fatty acids as alpha-linolenic acid. As such, HS and its oil may be used in hen diet formulations to produce eggs enriched in essential fatty acids. Because omega-3 eggs have the potential for unpleasant aromas and flavors, the current study was designed to assess the fatty acid profile and sensory attributes of eggs procured from hens consuming diets containing hempseed oil (HO) or HS. A total of 48 individually caged White Bovan hens received 1 of 6 diets containing 4%, 8%, 12% HO, 10%, 20% HS or 0% hemp (w/w) for 12 wk. Total omega-3 polyunsaturated fatty acid content was highest in the 12% HO group (15.3 mg/g of yolk) compared to the control (2.4 mg/g of yolk). Trained panellists (n= 8) found no significant differences (P≥ 0.05) in aroma or flavor between cooked eggs from different dietary treatments, with the exception of sweet flavor. The 4% HO group yielded the least sweet eggs compared to the 20% HS group, which was highest. For yolk color, L*, a*, and b* values (Mean ± SEM) for control eggs were 61.2 ± 0.10, 1.1 ± 0.05, and 43.0 ± 0.22, respectively. Addition of hemp led to significant (P < 0.001) reductions in L*, and significant increases in a* and b*, with the largest changes observed in the 20% HS treatment (L*= 58.7 ± 0.10; a*= 5.8 ± 0.05; b*= 60.5 ± 0.22). The results show that hemp use in hen diets leads to increased omega-3 polyunsaturated fatty acid content and color intensity of egg yolks, but does not have adverse effects on the sensory profiles of the cooked eggs. PRACTICAL APPLICATION: This study provides evidence that HS and hempseed oil (HO) can safely be utilized as feed ingredients for laying hens to produce table eggs that are enriched in essential fatty acids. Additionally, the eggs procured from these hens had similar aroma and flavor compared to eggs from hens not fed any hemp. The greater the dietary hemp inclusion, the more pigmented the resulting yolks became in terms of darkness, redness, and yellowness.     

Determination of ochratoxin A in eggs and target tissues of experimentally drugged hens using HPLC–FLD

Ochratoxins are fungal secondary metabolites that may contaminate various foods and beverages. The intake of ochratoxins by humans may result in typical syndromes (nefrotoxicity, carcinogenity, teratogenicity and immunotoxicity) and has been associated with Balkan Endemic Nephropathy (BEN). In this study we evaluated the effects of accumulation of ochratoxin A throughout the chain production of eggs, by investigating the dynamics of OA accumulation in eggs placed by laying hens experimentally exposed to OA.     

Excretion of oxytetracycline in eggs after medication of laying hens

The kinetics of oxytetracycline elimination into eggs were determined separately for albumen and yolk after oral administration through either drinking water (0.1-0.25 and 0.5 g/l for 5 days) or feed (300 and 600 ppm for 7 days) or after intramuscular injections (3 X 15 mg/kg body weight and 3 X 30 mg/kg body weight), 24 hours apart. Residues were assayed by a microbiological agar diffusion method, with Bacillus cereus as test-organism. The detection threshold was 0.07 micrograms/g for albumen and 0.2 micrograms/g for yolk. In all cases, the elimination period lasted longer for the yolk; it varied between 0 and 10 days after treatment was discontinued, according to administration routes and dosages. The conditions of oxytetracycline utilization in laying hens are discussed. The oral route only might be used to adhere to the proposals presented by the Joint FAO/WHO Expert Committee on Food Additives.     

我国蛋鸡养殖中药物残留分析研究及监管建议

目的 重点围绕抗生素类兽药的使用,对我国蛋鸡养殖中的药物残留情况进行分析研究并提出监管建议。方法 采用摸底调查、监督抽检和舆情收集的方式,了解国内蛋鸡养殖过程中的用药情况。通过梳理本中心五年来鸡蛋和鸡肉的检测数据,从检出项目、样品及来源分析不合格情况;通过收集舆情,汇总国内各省近年来鸡蛋和鸡肉抽检不合格的情况。结果 发现抗生素的使用确实广泛存在于我国蛋鸡养殖过程中,并经由鸡蛋和鸡肉进入到消费者市场;监督抽检的鸡蛋和鸡肉不合格的项目主要集中在氟苯尼考、恩诺沙星、磺胺二甲嘧啶等磺胺类和甲硝唑等兽药中,这四种药物均为广谱性的抗生素。结论 结合我国国情、借鉴发达国家的做法,提出七项监管建议,为监管部门能及早、有效、最大限度地降低兽药经蛋鸡养殖途径产生的食品安全风险提供参考。     

Doxycycline depletion and residues in eggs after oral administration to laying hens

The depletion of doxycycline (DC) residues in eggs was determined after oral drug administration by drinking water to laying hens. The antibiotic was supplied to birds for 5 consecutive days and the eggs were collected during medication and 18 days after withdrawal. DC residues were determined by LC-MS/MS. DC was isolated from eggs with a solution of 0.02 M of oxalic acid (pH 4), 0.1 M Na₂EDTA and acetonitrile. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 2 and 5 µg kg^–1, respectively. Analyses were performed on whole egg, egg white and yolk separately. DC was detectable 24 h after the beginning of administration. The concentration of antibiotic increased daily, resulting in the highest DC concentration in whole eggs at the first day of the withdrawal period. Thirteen days after withdrawal, the content of DC in whole eggs was below the LOQ of the method. However, some differences were found in the depletion curve of DC between egg white and yolk. Residues of DC in egg white were much higher during treatment and 1 day after withdrawal, but later the concentration in egg white decreased fairly rapidly and a higher DC content in egg yolk was observed. The depletion period was shorter for egg white than for yolk, and DC was detected in the egg white until 12 days after withdrawal and 2 days more in egg yolk than in white. DC reached a peak faster in egg white, but the residues were detectable for longer period in the yolk.     

Egg weight and production responses of laying hens fed rice pollard

Concentrations of rice pollard of 85 and 420 g kg^?1 were included in iso-energetic layer diets without any detrimental effect on production. Immediate improvements in egg weight and egg gradings were observed as a result of feeding rice pollard from point-of-lay; these presumably reflected increased dietary concentrations of linoleic acid. Varying responses to the two dietary rice pollard concentrations indicated strain differences in linoleic acid requirements during the early laying period. Rapid reductions in egg weight and egg gradings occurred when the rice pollard was removed at 48 weeks of age, the effect being most noticeable in birds previously fed the high concentration of rice pollard.     

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.     

一种富含红曲色素微生物发酵饲料 在蛋鸡养殖中的应用

选取健康32周龄海兰褐蛋鸡288只,随机分成3组,试验组分别添加0.5%和1.0%的富含红曲色素微生物发酵饲料,考察其对蛋鸡生产性能及蛋品质的影响。结果表明:添加0.5%富含红曲色素的微生物发酵饲料试验组与对照组相比,产蛋率提高了5.82%,破蛋率和料蛋比分别降低了12.36%和3.57%;而在蛋品质上,与对照组相比,平均蛋重和平均蛋黄质量分别提高了3.57%和1.38%,蛋黄中的胆固醇含量降低了5.17%;同时能显著加深蛋黄的红色度和黄色度。     

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.     

Residues of doxycycline and oxytetracycline in eggs after medication via drinking water to laying hens

Doxycycline (DOTC) and oxytetracycline (OTC) were dissolved in drinking water (0.5 g/l) and supplied to laying hens for 7 consecutive days. Eggs laid were collected daily during and after medication, and the antibiotic concentrations in the yolk and albumin were determined by the cup-plate method with Bacillus cereus var. mycoides ATCC 11778. The concentrations of both antibiotics were increased in yolk day by day with the advance in medication, reached peaks 2 days after withdrawal and then declined gradually. Mean peak concentrations in the yolk were 6.70 micrograms/g for DOTC and 1.42 micrograms/g for OTC. Peak concentrations in the albumin occurred in the middle stage of medication, where the mean values were 12.24 micrograms/g for DOTC and 1.03 micrograms/g for OTC. DOTC was detected in albumin until 24 days after withdrawal and for 2 days more in yolk than in albumin. OTC was detected in yolk until 9 days after withdrawal. The depletion period of OTC was shorter for the albumin, where the residue disappeared in all eggs 6 days after withdrawal. In spite of similarities between DOTC and OTC in structure, DOTC was deposited in higher concentrations and lasted for a longer period in eggs. This characteristic was considered due to its greater lipophilicity, closely correlated with oral absorption and tissue penetration.     

Enrichment of eggs in n-3 polyunsaturated fatty acids by feeding hens with different amount of linseed oil in diet

The production of n-3 polyunsaturated fatty acid enriched eggs by addition of linseed oil to the laying hens' diet has been evaluated in terms of production parameters and n-6/n-3 ratio. A total of 150 18weeks old Lohmann Brown laying hens were housed in cages and fed with basal diet and four experimental diets containing 1%, 2%, 3% or 4% of linseed oil added to the basal diet. The effect of the altered level of linseed oil on hens laying performance, fatty acid content and composition and cholesterol content in egg yolk has been evaluated during 13weeks of experiment. Egg weight, yolk fat content, yolk weight, yolk percentage and shape index were not influenced by dietary treatment. The ratio between n-6 and n-3 polyunsaturated fatty acids in eggs decreased in first 5weeks and then remained stable until the end of the experiment for all experimental groups. Different contents of linseed oil in feed highly influenced the n-6/n-3 ratio (P<0.0001). Addition of linseed oil did not influence the cholesterol content in yolks (P=0.5200) while the only factor affecting the cholesterol content was the hens age (P<0.0001).     

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.     

Aflatoxin and its metabolites in tissues from laying hens and broiler chickens fed a contaminated diet

Two groups of 32 hens and broiler chickens were contaminated with 2.5 and 5 mg of aflatoxin (AF) kg^?1 feed for a period of 32 days. During this contamination 16 birds were sacrificed and aflatoxin and its metabolites were detected using thin-layer chrotnatography and fluorescence densisometry. The tissues analysed (liver, muscle, kidney, gizzard and eggs) gave a wide range of concentrations, the lowest was found in ben muscle (0.05 μg kg^?1 of AFB₁) and the highest in gizzards from the 5 mg kg^?1 group of the hens (9.01 μg kg^?1 of AFB₁). Metabolites of AFB₁, AFM, and AFB_2a appeared in the liver but not in other tissues. In broiler's tissues, the following metabolities were isolated: AFM₁ and AFB_2a, in liver, aflatoxicol in muscle and AFM₁ and AFB_2a in kidneys, all having concentrations lower than AFB₁. Aflatoxicol was isolated from one egg sample (0.32 μg kg^?1). For both types of birds, aflatoxin clearance time was only 24 h for muscle and kidneys. In livers from the 5 mg kg^?1 group, AFM₁ and AFB_2a were still found 4 days after removal of the contaminated feed. In eggs and gizzards, aflatoxin residue was still detected on the 8th day of the clearance period although in low quantities. In the broiler's gizzards, clearance time was only 24 h. These results suggest that aflatoxin transfer to edible tissues is very small and the danger of contaminations to humans is also very small, except in the case of gizzards.     

Amino acid pattern in eggs as influenced by supplementation of dopamine agonists and antagonists in laying hens

A total of thirty laying hens divided into 3 equal groups was used. The 1st group served as control and was fed a basal ration. The 2nd and 3rd groups received L-Dopa and reserpine, respectively. The goal of the study was devoted to determine the effects of these additives on the rate of egg production, weights of eggs and yolks as well as yolk proteins and their amino acid pattern. In the reserpine-treated hens the rate of egg production was increased whereas in the L-Dopa-treated group, the weights of eggs and yolks, food intake as well as the amino acids aspartate, glutamate, glycine, alanine and methionine were significantly increased. The levels of tyrosine and histidine were decreased in both treatments while methionine was decreased by reserpine only. The addition of dopamine antagonist to a ration containing lysine and leucine in concentrations of 0.55% and 0.9% did not influence their levels in eggs. The increment of methionine, aspartate, glutamate and glycine by the dopamine agonist and their decrease by antagonist revealed that these amino acids are excitatory neurotransmitters in brain.