Submitted to: International Journal of Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/20/2013
Publication Date: 10/1/2013
Citation: Reyes-Herrera, I., Schneider, M.J., Blore, P.J., Donoghue, D.J. 2013. Screening blood samples to estimate when oxytetverycline residues exceed regulatory tolerances in poultry muscle. International Journal of Poultry Science. 12(6):348-352. Interpretive Summary: Use of antibiotics in food animals, and the potential for antibiotic residues requires monitoring of the food supply to ensure any residues present are below the acceptable levels established by the U.S. Food and Drug Administration. Allowed levels of tetracycline antibiotics have been established in chicken muscle, however extraction of residues for monitoring purposes from muscle can be more time consuming than from other matrices such as serum. In this work, oxytetracycline levels in dosed chickens were determined in both serum and muscle, and the relationship between these levels was established. This study allows for prediction of oxytetracycline levels in muscle based on results from serum, a more rapidly analyzed matrix. Thus, analysis of residues in serum can provide regulatory agencies such as FDA and FSIS a more efficient route to screen for oxytetracycline levels in muscle.
Technical Abstract: The presence of antibiotic residues in edible animal products is a human food safety concern. To address this potential problem, the government samples edible tissues, such as muscle, to monitor for residues. Due to loss of valuable product and analytical difficulties only a small percentage of poultry carcasses are tested. Alternatively, antibiotic residue concentrations could be screened in blood, which is readily available during carcass processing. To determine if blood concentrations are predictive of muscle concentrations, 252 market aged broilers were dosed with the antibiotic oxytetracycline (OTC) in water at three doses: the maximum OTC approved dose for broilers (800 mg/gal) or five or ten times that dose (4,000 or 8000mg/gal, respectively). Blood and muscle samples were collected prior to initial dosing (0 hour, controls), during the dosing period at 1, 3, 6, 12, 24, 48, 96 or 144 hours and at 12, 24, 36, 48 or 60 hours after drug withdrawal. Residues of OTC in blood and muscle were determined using a microbial inhibition method. Concentrations in both blood and muscle tissue followed similar time: concentration patterns, peaking 24 hours after initial dosing (396+/9 vs. 557+/37 ppb; 1,443+/48 vs. 1,846+/58 ppb or 2,447+/67 vs. 3,210+/36 ppb for the 1, 5 or 10x doses in blood vs. muscle respectively) and declined rapidly after withdrawal. These data suggest that blood samples may be used to predict OTC concentrations in muscle (by multiplying blood concentrations by 1.3) as a screening procedure for OTC residues in poultry.