Distribution of chloramphenicol to tissues, plasma and urine in pigs after oral intake of low doses

ABSTRACT

Toxic effects of chloramphenicol in humans caused the ban for its use in food-producing animals in the EU. A minimum required performance level (MRPL) was specified for chloramphenicol at 0.3 μg kg^–1 for various matrices, including urine. In 2012, residues of chloramphenicol were found in pig urine and muscle without signs of illegal use. Regarding its natural occurrence in straw, it was hypothesised that this might be the source, straw being compulsory for use as bedding material for pigs in Sweden. Therefore, we investigated if low daily doses of chloramphenicol (4, 40 and 400 μg/pig) given orally during 14 days could result in residues in pig tissues and urine. A dose-related increase of residues was found in muscle, plasma, kidney and urine (showing the highest levels), but no chloramphenicol was found in the liver. At the lowest dose, residues were below the MRPL in all tissues except in the urine. However, in the middle dose, residues were above the MRPL in all tissues except muscle, and at the highest dose in all matrices. This study proves that exposure of pigs to chloramphenicol in doses occurring naturally in straw could result in residues above the MRPL in plasma, kidney and especially urine.

KEYWORDS:

• Chloramphenicol
• pigs
• residues
• distribution
• LC-MS/MS

Acknowledgments

The authors thank the staff at the animal facilities at the NVI, especially Annika Daggfeldt and Per Karlsson. They also thank Team pre-analysis at the NFA, particularly Jannika Bergman, Hanna Thorén for the analysis of urine and muscle at the Department of Chemistry at the NFA, Leif Busk at the NFA for participating in the first planning of the experiment and for making efforts to find funding for the experiments. Furthermore, they thank the RIKILT staff, especially Stanislava Vonsovic, for the analysis of chloramphenicol in urine, tissues and plasma.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The analysis carried out at RIKILT was funded by the Dutch Ministry of Economic Affairs and the Netherlands Food and Consumer Product Safety Authority (NVWA).