Oxytetracycline Residues and Their Antibacterial Activity in Eggs Laid by HensAdministered by Therapeutic Dose of Oxytetracycline via Drinking Water

Eggs laid by laying hens administered oxytetracycline via drinking water with dose 2 g/l for 7 consecutive days were evaluated their oxytetracycline residues and antibacterial activity on the 2 nd , 4 th , 6 th day of administering and the 2 nd , 7 th , 14 th day of stopping. The results indicated that oxytetracycline residues and their antibacterial activity had been found in egg shells and eggs, white since 2 nd day of administering, whereas in yolks since the 4 th day. The residues were still found both in eggs, white and yolks at concentration of 0.01 ppm on the 7 th day of stopping oxytetracycline administration. The oxytetracycline residues concentration of 0.01 ppm were under permitted maximum residue limit, however there still showed antibacterial activity in eggs white, while there were no antibacterial activity in yolks. Eggs had been free from oxytetracycline residues and their antibacterial activity on the 14 th day of stopping oxytetracycline administration to hens. Keywords : oxytetracycline, hen, egg, residue, antibacterial activity