Withdrawal period for Coxidin® for chickens and turkeys for fattening and re-examination of the provisional Maximum Residue Limit

Following a request from the European Commission, the European Food Safety Authority was asked to deliver a scientific opinion on the proposal for reducing the withdrawal period from three days to one day and the setting of a final maximum residue limit (MRL) for the product Coxidin® for chickens and turkeys for fattening. No data which would allow proposing a final MRL for monensin in poultry tissues was provided. A number of monensin metabolites (M1, M2, M5, M6) were isolated and tested for their biological activities. All monensin metabolites tested appeared to show lower ionophoric activity than the parent compound. These findings confirm the results of earlier studies. Comparable results on reduced ionophoric activity of metabolites from a related polyether antibiotic support the above findings on monensin. Non-extractable residues in chicken liver and kidney after a one-day withdrawal period amount to more than 50 % of the total residues. About 90 % of total radioactivity was associated with the abdominal fat in chicken for fattening. In milk, about 25 % of the total residues are attributed to fatty acids. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concludes that a considerable part of the non-extractable residues is not drugrelated. The FEEDAP Panel, following a weight of evidence approach, concludes that monensin derived residues of toxicological relevance probably represent, as a conservative estimate, not more than 50 % of the total residues. After applying a 50 % reduction of the toxicological relevance of total residues, the human exposure would amount to 0.103 mg day-1 (57 % of the ADI). Based on the existing MRL values, the consumption of chicken edible tissues would contribute to 51 % of the ADI. Recent marker residue data obtained after one-day withdrawal in chicken for fattening were below the MRLs. Therefore, a one-day withdrawal time for Coxidin® for chickens and turkeys for fattening could be set.