Investigation of doxycycline residues in bones after oral administration to broiler chickens.

Introduction: Chicken bones, a by-product of the poultry industry, can directly or indirectly enter the food chain. Bone meal and bone products could be sources of many contaminants. Considering the wide range of uses made of bones in the culinary and food industries, this material needs to be safe and antibiotic residue-free. To determine if such is the case, the concentration of doxycycline in chicken bones was investigated, this antimicrobial being one of the most commonly used in poultry production. Material and Methods: Ross 308 broilers were grouped into three experimental and one control group. Doxycycline was administered in drinking water at therapeutic and sub-therapeutic doses, as well as via spray treatment. The concentration of doxycycline in bones was determined post slaughter by ultra-high performance liquid chromatography-tandem mass spectrometry. Results: Doxycycline was quantified at 135 µg/kg 22 days after the last day of antibiotic administration at therapeutic doses; 2,285 µg/kg after sub-therapeutic treatment for 27 days and 9.62 µg/kg 22 days after the end of spray application. Conclusion: High concentrations and long persistence of doxycycline in bones were found in this study. Doxycycline can contaminate all bone-derived products in the food and fertiliser industries.

Risk to Public Health Regarding Doxycycline Residues in Chicken Claws.

Doxycycline residues in claws may pose a potential risk to humans. A study with broiler chickens was performed to find the concentrations of doxycycline in claws after treatment. For the quantification of the antibiotic of interest in claws, an ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed. Doxycycline was detectable at 3043 µg/kg at sub-therapeutic treatment, 223 µg/kg after therapeutic doses, and 14 µg/kg after spray application on the last day of the experiment (day 22). Almost 70 days is required for the concentration of doxycycline to reach zero. The obtained results show that monitoring of doxycycline in claws should be implemented.

Determination of Polypeptide Antibiotic Residues in Food of Animal Origin by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

A novel UHPLC-MS/MS method for the determination of polypeptide antibiotic residues in animal muscle, milk, and eggs was developed and validated. Bacitracin A, colistin A, colistin B, polymyxin B1, and polymyxin B2 were extracted from the samples with a mixture of acetonitrile/water/ammonia solution 25%, 80/10/10 (v/v/v), and put through further evaporation, reconstitution, and filtration steps. The chromatographic separation was performed on a C18 column in gradient elution mode. Mass spectral acquisitions were performed in selective multiple reaction monitoring mode by a triple quadrupole mass spectrometer. The method was validated according to the criteria of Commission Decision 2002/657/EC. The method quantifies polypeptides in a linear range from 10 to 1000 µg kg-1, where the lowest concentration on the calibration curve refers to the limit of quantification (LOQ). The recoveries ranged from 70 to 99%, the repeatability was below 13%, and within-laboratory reproducibility was lower than 15%. The decision limit (CCα) and detection capability (CCß) values were calculated, and ruggedness and stability studies were performed, to fulfill the criteria for confirmatory methods. Moreover, the developed method may also be used for screening purposes by its labor efficiency.

Residue control of coccidiostats in food of animal origin in Poland during 2007-2010.

Coccidiostats are widely used as feed additives to prevent coccidiosis. The off-label use of anticoccidials or feeding non-target animals with cross-contaminated feedingstuffs may result in the occurrence of coccidiostat residues in animal tissues and eggs. In EU countries, food of animal origin is subjected to official control of residues according to Council Directive 96/23/EC. In Poland, within the framework of the National Residue Control Plan, 3718 samples (3533 targeted and 185 suspect) of animal liver, eggs, drinking water and feed were tested for coccidiostats between 2007 and 2010. Violative residues of nicarbazin, lasalocid, maduramicin, salinomycin, semduramicin and robenidine were detected in 77 food samples (53 samples of chicken liver, 23 samples of eggs and 1 sample of turkey liver). A high percentage (31%) of non-compliant feed samples collected during follow-up investigations was observed, which confirms that feed cross-contamination may be the reason of the occurrence of coccidiostat residues in food.