氟苯尼考在鸡蛋和蛋鸡组织中的残留规律及预测模型建立

氟苯尼考是一种被广泛应用于动物养殖过程中的抗生素药物，可能残留于畜产品中，被人类长期食用会对机体造成耐药性、免疫抑制等不良影响。本实验旨在探讨蛋鸡摄入不同剂量氟苯尼考后，鸡蛋及各组织中氟苯尼考及其代谢产物氟苯尼考胺的清除规律，建立残留预测数学模型。本实验选取处于产蛋高峰期的罗曼粉壳蛋鸡250 只（350 日龄、体质量（1.97±0.07）kg），随机分为5 组，每组50 只，分别给予氟苯尼考0（对照）、30、60、120、240 mg/（kg mb·d），连续给药5 d。采用液相色谱-串联质谱法测定不同休药时间点蛋黄、蛋清、卵黄、肌肉、肝脏中氟苯尼考及其代谢产物氟苯尼考胺的残留含量。结果表明：休药1～3 d时，240 mg/（kg mb·d）剂量组蛋鸡产蛋率与其他处理组相比显著降低（P＜0.05），休药4 d后恢复至对照组水平；氟苯尼考及其代谢产物氟苯尼考胺在产蛋鸡组织中残留含量分布：蛋黄＞卵黄＞蛋清＞肝脏＞肌肉；不同组织残留氟苯尼考及氟苯尼消除所需休药时间：肝脏＜肌肉＜蛋清＜蛋黄＜卵黄；氟苯尼考给药剂量和休药时间对残留含量影响高度显著（P＜0.001），且给药剂量与休药时间互作效应高度显著（P＜0.001）。休药时间、给药剂量和残留含量之间呈现二元二次回归关系（P＜0.001）。为达到《中国兽药典（2015年版）》所规定的氟苯尼考给药剂量范围（40～60 mg/（kg mb·d）），肌肉等组织需休药1 d、蛋清蛋黄需休药13 d、卵黄需休药21 d。     

Long-term administration of low doses of mycotoxins to poultry. 1. Residues of aflatoxin B1 and its metabolites in broilers and laying hens

A study was performed to determine aflatoxin residues in tissues and organs of male broilers and hens that had been fed a diet contaminated with 50 micrograms/kg aflatoxin B1 (AFB1). Residue levels of AFB1, aflatoxicol (Ro), aflatoxin M1 (AFM1) and aflatoxin B2a (AFB2a) were determined by an HPLC method and, with the exception of AFB2a, were detected in the liver, kidney and thigh of both male broilers and hens. The highest levels found were for Ro in liver (1.10 and 0.60 micrograms/kg for male broilers and hens, respectively). On the other hand no detectable amounts of aflatoxins were found in any tissue after withdrawal periods of 14 and 33 days for male broilers and laying hens respectively.     

The residue levels of narasin in eggs of laying hens fed with unmedicated and medicated feed

Laying hens were fed contaminated feed containing narasin 2.5 mg/kg for 21 days followed by a 7 day withdrawal period, hens in the control group were fed unmedicated feed. Eggs were collected during trial days 0, 3, 7, 14, 21 and after the withdrawal period of 7 days. The concentration of narasin in yolks and egg whites was analyzed by a liquid chromatography-mass spectrometry method. Narasin was found to accumulate in yolks, where the narasin concentration increased during the treatment. The concentration of narasin varied from 5.9 to 13.8 microg/kg (mean 10.6 microg/kg) in yolks after 21 day feeding periods. The concentrations of narasin ranged from < 0.9 to 1.4 microg/kg after the withdrawal period. Narasin residues were not found in egg whites of the laying hens fed contaminated feed nor in either yolks or egg whites of the laying hens fed unmedicated feed. The effect of cooking was also tested on the amount of narasin residues in eggs. Cooking for 10 min did not significantly influence the narasin residues in eggs. Traces of lasalocid were also found in the yolks. The traces of lasalocid are attributable to an accidental contamination of the feed during its manufacture.     

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.     

Ovarian autoimmunity in relation to egg production in laying hens

The aim of this study was to determine whether anti-ovarian autoantibodies appear in the circulation of laying hens and whether the concentrations of these antibodies change with respect to ageing and egg laying rate. Autoantibodies to ovarian tissues in the circulation of aged (aged approximately 670 days) White Leghorn hens with low (< 50%) and high (> 90%) egg laying rates were examined by ELISA and western blotting. Young laying hens (aged 185 days) with > 95% egg production were used as controls. The results of the ELISA indicated that IgG, which bound to the ovary and small white follicles, was present in the circulation of old laying hens. More hens that laid few eggs had circulatory autoantibodies to the ovary and small white follicles, as determined by the cut-off value in ELISA (mean absorbance + 2 SD of young laying hens), than did hens that laid greater numbers of eggs, and the concentration of IgG was significantly higher in the hens that laid few eggs. In contrast, when the muscle proteins were used as antigens there were no significant differences in the absorbance values among low and high laying frequency old hens or young hens. Western blotting revealed many bands of immunoprecipitates formed by ovarian antigens and antibodies in the serum of old hens, indicating the presence of many binding sites for circulatory IgG in ovarian tissues. These results indicate that antibodies to ovarian tissues appear in the circulation of laying hens during ageing, and that the concentration of these autoantibodies is related inversely to the rate of egg laying by hens.     

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.     

An automated HPLC determination of meticlorpindol in eggs with UV absorbance detection, using on-line dialysis and pre-concentration as sample clean-up; occurrence in and carry over to eggs

A fully automated HPLC determination of the coccidiostat meticlorpindol in whole egg, egg white and yolk is described. The sample homogenate is dialysed on-line against water. The dialysate is concentrated on-line on a short reversed-phase (RP) column. The contents of this column are transferred to the reversed-phase analytical column by means of the mobile phase. Meticlorpindol is detected using an absorbance detector at 270 nm. Linear calibration graphs are obtained in the range 40-900 ng/g in whole egg and egg white (detection limit 10 ng/g) and 80-1800 ng/g in yolk (detection limit 20 ng/g). Out of 111 commercially obtained egg samples 12 contained meticlorpindol with levels varying from 10 to 433 ng/g. A group of laying hens, kept in cages, received 10 mg/kg of Lerbek (meticlorpindol and methylbenzoquate; Dow Chemical) in the feed for 10 days. Meticlorpindol residues in the eggs rose to a level of 622 ng/g. Meticlorpindol was found in the eggs until 6 days after withdrawal of the medicated feed. Another group received 110 mg/kg in the feed. Meticlorpindol residues rose to levels of 4480 ng/g in the eggs, 5880 ng/g in the egg white and 2660 ng/g in the yolk. Meticlorpindol was found in the eggs and the egg white until 14 days and in the yolk until 8 days after withdrawal of the medicated feed.     

Dose-response feeding study of short chain chlorinated paraffins (SCCPs) in laying hens: effects on laying performance and tissue distribution, accumulation and elimination kinetics

Technical short chain chlorinated paraffins (C10-C13 with 60% chlorine) were fed to 93 laying hens from 24 to 32 weeks of age in increasing concentrations of up to 100 mg/kg feed. No significant influence on health, relative organ weights or performance (laying intensity, egg weight, feed consumption) was noted. The chlorinated paraffin content of the tissues was linearly related to the concentration of short chain paraffins of the feed. The highest concentrations were found in abdominal fat, egg yolk and fatty tissues. Breast muscle, egg albumen and bile fluid contained minimal or no residues. Less than 1% of the chlorinated paraffins ingested were incorporated into the body (without head, feet, gut and feathers), whereas about 1.5% were eliminated with the egg yolk and 30% were excreted with urine and faeces. A six-week kinetic depuration study revealed a biphasic elimination with half-lifes of 4-40 min (liver, kidneys, legs, fat, blood) for the initial rapid phase, and 15-30 days (blood, fat, liver, yolk, kidneys, legs) for the terminal slow phase.     

产前饲喂模式下恩诺沙星在初产蛋中的残留规律及膳食暴露评估

目的 消费者长期食用残留恩诺沙星的禽蛋会造成耐药性、过敏反应以及肠道菌群紊乱。本试验旨在探讨蛋鸡产蛋前喂饲恩诺沙星在初产蛋中残留规律,评估其对鸡蛋安全性以及消费者健康的影响。方法 选取378只日龄为85天的海兰褐蛋鸡,根据给药时间分为14组,1.5 g/kg恩诺沙星粉剂,连续拌料喂药 5 d。从给药后生产第 1 枚鸡蛋开始连续采集鸡蛋8天,分析鸡蛋中恩诺沙星及其代谢产物环丙沙星残留量,采用每日允许摄入量对安全性进行评估。结果 初产蛋中恩诺沙星和环丙沙星含量均随着停药时间延长逐渐降低。给药5d,停药1天的初产蛋中恩诺沙星和环丙沙星含最高分别为959.725 mg/kg和62.263 mg/kg,停药7d后鸡蛋中环丙沙星含量低于检出限,痕量恩诺沙星代谢缓慢,停药24d后鸡蛋中恩诺沙星含量低于检出限。停药1d的初产蛋对儿童和成年人身体健康具有慢性危害风险。结论 为了保证禽蛋中无恩诺沙星残留建议至少需要在产蛋前29天用药,停药24天以上,以满足产品符合国家监管以及保证消费者健康的要求。     

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.     

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.     

DISTRIBUTION OF OCHRATOXIN A IN CHICKEN TISSUES AND EGGS

The kinetics of distribution of ochratoxin A (OA) in chicken tissues was studied. Day-old chicks were fed a starter diet alone or containing 1 ppm OA. After 5 weeks, all chicks were intubated with 50 μg ³H-OA per chick. The highest level of radioactivity was found in kidney and liver 8 hr after intubation. Peak levels of OA in kidney, liver and breast were found to be 12, 4, and 0.2 ppb, respectively. Over 90% of the radioactivity was eliminated 48 hr after intubation. Moreover, when laying hens were fed a diet containing 0.5 or 5.0 ppm of OA for 2 weeks, the highest levels of OA were found in the kidney (124 ppb) and liver (80 ppb) also. Levels of OA in breast, leg and eggs of laying hens were found to be 8, 7, and 2.8 ppb, respectively.     

Determination of lasalocid residues in the tissues of broiler chickens by liquid chromatography-tandem mass spectrometry

Lasalocid is a polyether ionophoric coccidiostat used for the prevention of coccidiosis in poultry at a prescribed concentration and during a certain time interval. Due to a public health concern about the presence of coccidiostat residues in poultry, the aim of the present study was to determine the levels of lasalocid residues in the edible tissues of broiler chickens (breast muscle, thigh muscle, heart, liver, gizzard, kidneys and skin/fat) fed commercially produced feed containing 100?mg?kg?1) of lasalocid in complete feed throughout the 5-day withdrawal period (WP). The residues were investigated by liquid chromatography coupled with electrospray ionisation (ESI) tandem mass spectrometry (MS/MS) with triple quadrupole. The limit of detection (LOD) and the limit of quantification (LOQ) of the method were 0.47 and 1.44?μg?kg?1, respectively. The average recovery based on the matrix-fortified calibrations for chicken tissues ranged between 79% and 98%. Lasalocid was found to accumulate in the liver, followed by the heart, skin/fat, kidneys, thigh muscle and gizzard. The lowest concentrations of lasalocid residues were found in the breast muscle. On day 5 of the WP, residue concentrations of lasalocid did not decline below the LOQ of the method, but were far below the maximum residue level (MRL) established for lasalocid in poultry from 20 to 100?μg kg?1 by European Commission Regulation (EU) No. 37/2010. The results confirmed that the WP established for lasalocid is sufficient to ensure the decline of its residues in the tissues of broiler chickens to the safe residue level.     

Eggs and poultry meat as tocopherol sources in dependence on tocopherol supplementation of poultry diets

One feeding trial with broilers and three feeding experiments with layers were carried out to investigate the influence of various vitamin E supplementations on α-tocopherol concentration of foods of poultry origin. Vitamin E content of basal diets amounted to ≈20 mg per kg feed; 0, 100, 1000, 10 000 and 20 000 mg vitamin E per kg feed were added. Broilers were fed for 30 days and slaughtered, layers were kept for one laying year (13×28 days), eggs were collected daily. Vitamin E concentration was determined in muscle (breast, legs), liver, fat and eggs by HPLC. Tocopherol concentration increased with vitamin E supplementation in all samples. The highest tocopherol concentration was measurement in egg yolk (254.9) followed by liver (44.8) and muscle (12.2 mg/100 g). Vitamin E supply of poultry feed depends on costs of vitamin E and financial benefits for the farmer.     

磺胺甲噁唑和磺胺嘧啶在青石斑鱼组织中的分布及代谢规律

通过一次性投喂各含有200 mg/kg磺胺甲噁唑（sulfamethoxazole,SMZ）和磺胺嘧啶（sulfadiazine,SDZ）的饲料,研究两种药物在青石斑鱼中各组织分布与消除规律。采用超高效液相色谱-串联质谱检测青石斑鱼各组织中SMZ和SDZ的含量,并用内标法定量。结果表明,SMZ在青石斑鱼各组织中的最大含量：肝脏、背肌、血浆、肾脏和鳃依次为827.97μg/kg、776.70μg/kg、610.29μg/L、432.14μg/kg和345.18μg/kg。SDZ在青石斑鱼各组织中的最大含量：肝脏、背肌、鳃、血浆和肾脏依次为895.30μg/kg、660.55μg/kg、431.88μg/kg、419.56μg/L和310.67μg/kg。SMZ在青石斑鱼各组织中的半衰期：肾脏、鳃、背肌、血浆和肝脏半衰期依次为26.65、21.00、20.38、18.73h和16.90h。SDZ在青石斑鱼各组织中的半衰期：肾脏、血浆、鳃、背肌和肝脏依次为31.50、27.72、24.75、21.66h和18.24h。SMZ和SDZ在青石斑鱼肝脏中半衰期最短,代谢速度最快;在肾脏中半衰期最长,代谢速度最慢。在水温（25±2）℃条件下,SMZ和SDZ各200mg/kg的剂量同时单次投喂青石斑鱼,建议休药期不低于3d。SMZ和SDZ代谢规律研究为磺胺类药物在水产品中的合理使用提供了参考。     

The effect of a hypocrellin A enriched diet on egg yolk quality and hypocrellin A distributions in the meat of laying hens

Hypocrellins, including hypocrellin A and hypocrellin B, are natural red pigments isolated from a traditional Chinese medicine. The present work was designed to investigate the influence of dietary HA supplementations on the colour and emulsifying properties of egg yolk and HA distributions in tissues of laying hens. A Chinese hen breed (black-bone silky fowl) was used. Ninety-six layers were assigned randomly to diets containing 0, 10, 30 and 50 mg HA per kilogram for 21 days. HA concentrations in egg yolk and tissues of laying hens such as ovary, liver, lung, heart, gizzard and breast muscle were determined by HPLC. Dietary HA supplementations improved the colour of egg yolk (P < 0.05), whereas no significant differences (P > 0.05) in the emulsifying properties of egg yolk were observed. There was a dose-dependent manner increase in egg yolk HA content in response to dietary HA supplementations (P < 0.05). The highest HA concentration was measured in ovary followed by liver and egg yolk.     

Long term administration of low doses of mycotoxins in poultry. 2. Residues of ochratoxin A and aflatoxins in broilers and laying hens after combined administration of ochratoxin A and aflatoxin B1

The effects of combined administration of ochratoxin A (OA) and aflatoxin B1 (AFB1) on the occurrence and the levels of residues of mycotoxins in poultry have been investigated. Male broilers and laying hens were fed from 14 days old with standard diets contaminated with 50 micrograms/kg OA and 50 micrograms/kg AFB1. Two groups of broilers and hens were withdrawn from contaminated feed at 37 and 88 days, respectively. At the time of sacrifice no significant lesions were found. Residues were compared with those found after administration of either toxin alone in former trials. Combined treatment resulted in higher content of OA in broiler livers (40 versus 5.0 micrograms/kg) and, to a lesser extent, in kidneys and skin, and of AFB1 in broiler liver and kidney (0.15 versus 0.02 microgram/kg and 0.40 versus 0.05 microgram/kg respectively). Laying hens showed smaller differences (0.20 versus 0.10 microgram/kg in liver and 0.32 versus 0.08 in kidneys). Withdrawal from treatment led to the almost complete disappearance of OA residues in broilers and in hens. These results show a synergistic effect of OA and AFB1, particularly in broilers.     

Reduction of aflatoxins by Korean soybean paste and its effect on cytotoxicity and reproductive toxicity--Part 3. Inhibitory effects of Korean soybean paste (doen-jang) on aflatoxin toxicity in laying hens and aflatoxin accumulation in their eggs

This study was conducted to determine the effects of Korean soybean paste (doen-jang [dwen-jahng]) (at concentrations of 0.5, 1, and 5%) on the toxicity of 500 ppb of aflatoxin in the diets of 60 laying hens (Isa Brown) divided into five groups and treated from week 15 to week 67. The aflatoxin-treated hens exhibited many deleterious effects, including reduced body weight; increased relative organ weights; decreased egg production; aflatoxin accumulation in eggs; decreased serum calcium, phosphorus, and alanino amonotransferase (ALT) levels; increased serum gammaglutamil transferase and lactic dehydrogenase levels; and, most significantly, severely altered cell foci and sinusoid dilatation in the liver, relative to control hens. The feeding of 1% soybean paste to hens reduced the adverse effects of aflatoxin on body weight, relative organ weights, egg production, and aflatoxin accumulation in eggs and improved serum calcium and ALT levels and the histopathological lesions of the liver. The feeding of 5% soybean paste to hens resulted in higher levels of the same types of improvements, especially with regard to the histopathological findings for the liver. On the basis of these results, it was suggested that a diet including 5% (and in some cases only 1%) Korean soybean paste protected laying hens and their eggs from the major deleterious effects of 500 microg of aflatoxin per kg of diet and from aflatoxin accumulation. These results indicate that dietary supplementation with Korean soybean paste reduces aflatoxin toxicity in laying hens that ultimately produce human foods such as eggs and poultry.     

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.     

Validation of HPLC method of analysis of tetracycline residues in eggs and broiler meat and its application to a feeding trial

HPLC with ion-pairing chromatography and diodearray detection at 355nm was used to determine tetracycline antibiotics in eggs and broiler meat. The analytical methods were optimized and validated. The mean recovery values for oxytetracycline for eggs and for tetracycline for breast meat were 76% . The withinday precision ranged from 8.0 to 11.8% for oxytetracycline in eggs and from 6.1 to 15.5% for tetracycline in breast meat. The between-day precision was 4.8% and 5.0% respectively for oxytetracycline in eggs and tetracycline in breast meat. The limit of detection and the limit of quantitation for oxytetracycline in eggs were 2.2 and 13.0ng/g respectively. These limits for tetracycline in breast meat were 10.5 and 20.9ng/g respectively. Residue values of tetracycline antibiotics in eggs and broiler meat were determined after oral administration of medicated feed. Medicated feed with 840mg/kg oxytetracycline was provided to laying hens for seven successive days. Two days after the administration was stopped, the mean oxytetracycline residue value in the eggs was already lower than the Maximum Residue Limit (MRL)-level and reached 118ng/g. Broilers were supplied with medicated feed containing 480mg/kg tetracycline for seven successive days. Four days after the administration was stopped, the mean tetracycline residue value in breast meat decreased below the MRL and was 86ng/g.