Evaluation of the oxytetracycline tissue residues in broiler chicken

The present study was undertaken to investigate the pharmacokinetics and tissue residue of oxytetracycline @ 50 mg.kg⁻¹ in poultry birds following single and multiple (7) dose oral administration. The concentration of oxytetracycline in plasma and tissue of these birds was analysed by High Performance Liquid Chromatography (HPLC). Following single dose oral administration the highest tissue concentration was observed in kidney (1.89±0.42jg.g⁻¹) followed by liver (1.75±0.24 |jg.g⁻¹), muscle (1.17±0.82jg.g⁻¹), intestine (1.67±0.61 jg.g⁻¹), fat (1.03±0.27 jg.g⁻¹) and skin (1.02±0.33 jg.g⁻¹) at 24hrs. At 96h post administration no residue of oxytetracycline could be detected in any tissue following single dose administration. In multiple (7) dose oral administration the highest concentration was found in kidney (4.54±1.07 jg.g⁻¹) at 24 hrs which decreased to 0.10±0.02 jg.g⁻¹ at 96hrs.The residue level in liver and muscle was found to be 4.31±0.59 jg.g⁻¹ and 3.18±0.47 jg.g⁻¹, respectively, at 24h post administration. At 144h post administration, no residue of oxytetracycline could be detected in any tissue following multiple (7) dose oral administration. Based on the findings, it was concluded that tissue residues could not be detected at 96h and 144h following single and multiple dose oral administration, respectively in broilers, hence, a withdrawal period of 3 days and 5 days is recommended following single and multiple doses, oral administration of oxytetracycline respectively in broilers.