産卵鷄에 抗生物質 添加飼料給與時 鷄卵의 殘留

Studies on residues of antibiotics in eggs reared with feedstuffs added to some antibiotics in layer chickens

The layer chickens which were 440 days old of age were reared with feedstuffs containing zinc bacitracin(50 ppm and 250 ppm), virginiamycin(50 ppm and 250 ppm) and chlorotetracycline hydrochloride(200 ppm) for obtaining basic data of the antibiotic residue levels in eggs. The each experimental groups were designed as 110 layer chickens. The rearing procedures of these chickens were performed as described Yamakishi from April to November in 1989. The residues of antibiotics in the egg yolks and whites were assayed by paper disk method. The eggs from these chickens reared as feedstuffs containing 50 ppm virginiamycin and zinc bacitracin were not detected any antibiotics in the egg yolks and whites. In the eggs from these chickens, trace antibiotics were detected in the egg yolks and whites at 2 and/or 3 weeks after rearing with feedstuffs containing 250 ppm of virginiamycin and zinc bacitracin. When the chickens were fed as feedstuffs containing 200 ppm of chlorotetracycline hydrochloride, the antibiotic was detected trace levels in the egg yolks and whites at the 6th and 7th day. After 5 weeks reared with these feedstuffs, the residue levels of chlorotetracycline were detected 0.11 ppm in the egg yolks and 0.09 ppm in the egg whites, respectively. In the groups of the chickens reared with feedstuffs containing 250 ppm of virginiamycin and zinc bacitracin, the antibiotics were not detected in the egg yolks and whites as the 2nd and 3rd day after feeding discontinuance of the antibiotics. In case of the group of the chickens reared with feedstuffs containing 200 ppm of chlorotetracycline, the antibiotic was not detected in the egg yolks and whites at the 2nd day after feeding discontinuance of the antibiotic.