Ceftiofur distribution in plasma and tissues following subcutaneously administration in ducks

A study was performed to determine the residues in blood and edible tissues of healthy ducks (25 days old, mean body weight 1.0+/-0.13 kg) after subcutaneous administration of ceftiofur sodium at a dose rate of 2 mg/kg body weight (Group I) and 4 mg/kg body weight (Group II). Blood, muscle, liver, kidney, and fat samples were collected from all of ducks on the 1st, 2nd, 3rd, 4th, and 5th day after treatment of drug, and ceftiofur was analyzed with a high-performance liquid chromatography (HPLC) assay with results reported as ceftiofur-free acid equivalent (CFAE). To study the spiked recovery, blank plasma and tissues were spiked with two different concentrations of ceftiofur sodium (0.1, 0.5 microg/g). Average recovery values for all samples ranged from 70.3 to 87.3%. In the group I, desfuroylceftiofur acetamide (DCA) was not detected in all of plasma, muscle, liver, and fat tissues on the 1st day after treatment. But, kidney samples on the 1st day were detected DCA (0.059+/-0.01 microg CFAE/g tissue). On the 2nd day of post-treatment, the concentrations of DCA in all tissues were lower than the detection limit, 0.05 microg CFAE /g tissue. In the group II on the 1st day after treatment, the concentration of DCA was 0.124+/-0.06 microg CFAE/g tissue, 0.103+/-0.03 microg CFAE/g tissue, and 0.071+/-0.010 microg CFAE/g tissue in plasma, kidney, and muscle samples, respectively. On the 2nd day after treatment of ceftiofur, the concentrations of DCA in all tissues were lower than 0.05 microg CFAE/g tissue. According to our results, the concentrations of DCA on the 1st day after treatment with 2 mg/kg body weight were below 0.05 microg CFAE/g tissue equivalent in all tissues except for kidney. On the 2nd day after administration at the dose of 4 mg/kg body weight, no DCA was also detected in all of the tissues although DCA was detected in all samples on the 1st day.