Current Cituation Of Drugs Used For Layers And Detection Of Residues And Study Of Controls In Dongtai City

The problem of residues of drugs in eggs has been taking highly paid byall countries in the world because of its important position in the food ofmankind. Our country and many other countries and internationalorganizations all took the controls. The report investigated the use of drugs forlayers, detected the residues of drugs and drew up the key controls that wereused for six farms in comparison of other six farms in Dongtai city which isone of the most county of raising poultry in Jiangsu province.1,There are clear that the kinds and varieties of antibacterial drugs usedfor layers are very extensive. Tetracyclines and beta-lactams and quinolonesare most in use among the antibacterial drugs, and their annual average usepercentages to one household are 35.7%, 31.3% and 27.1% respectively.Doxycycline and amoxicillin and ciprofloxacin are most in use among theantibiotics, and their annual average use percentages to one household are26.3%, 22.4%, 21.6% respectively. The kinds and varieties of antibacterialdrugs are very different in use due to different raising scales, styles andseasons, different ways for taking drugs, different purposes .On the basis ofinvestigation, the causes of the more residues of drug in eggs are analyzed.2,The residues of doxycycline and ciprofloxacin and others in eggssampling from the chicken farms were detected by using LC-MS, ELISAreagent box and immune colloidal gold reagent board(IGB). (1) The rate ofdoxycyclines residues in eggs was 81.5% after detection of 38 samples byELISA reagent box, and six samples were .higher than 200ppb (15.8%), inwhich 4 samples from the farms of 5000 layers, other 2 samples from thefarms of more than 5000 layers, and 25 samples were lower than200ppb(65.7%), and the other 7 samples were lower than the detectionlimit(18.5%). (2) The result of residues of quinolones in eggs from 24 farms inDongtai city, detected by IGB, is followed: 4 samples were positive (one was false) whereas 20 samples were negative, and the accuracy was 95.8%. 3positive samples were all from the farms of 1000-5000 layers that should bethe important ones in controlling drug residues. After detection of residues ofquinolones in eggs sampled from markets, 2 samples were positive among 18samples, positive rate was 11.1% . The measurement was not found, yet inChina. (3) The result of residues of doxycycline in eggs detected by LC-MS isfollowed: after the layers drank the solution of 200 ppm doxycycline for fivedays, everyday 45.45mg for one layer, residues of doxycycline in eggs were0.94mg/kg, 0.67mg/kg, 0.27mg/kg respectively in the third, fourth and fifthdays of using drug, which were all higher than 0.20 mg/kg (MRL),and were0.092mg/kg, 0.077mg/kg in the sixth, seventh days of withdrawal of drug,and were eliminated slowly. (4) The result of residues of ciprofloxacin in eggsdetected by LC-MS is followed: After the layers drank the solution of 98ppmciprofloxacin for five days, everyday 19.6mg for one layer, residue ofciprofloxacin in eggs was 17.4μg/kg in the fourth day of using drug, and was9.2μg/kg in the first day of withdrawal of drug, and residues of ciprofloxacinin eggs were all lower than 10μg/kg. It is clear that residues of ciprofloxacin ineggs were all lower than 10μg/kg after the sixthday of withdrawal of drugeven if the dose of ciprofloxacin was as double as that of directions.3,In order to control drug residues in eggs, key methods that includedspecification of safe use of veterinary drug were laid down and applied to thechicken farms to compare the drug residues before the usage with the onesafter the usage. The egg samples, 8 each farm, were detected to know theresidues of quinolones and doxycyclines. The results were as followed: theresidues of quinolones decreased from 0.068 mg/kg before the use of keymethods to 0.025 mg/kg after the use of key methods, The rate of residue overcriterion(0.1mg/kg) decreased from 10.4% to 0 .Meanwhile, the residues ofdoxycyclines decreased from 0.105 mg/kg to 0.06 mg/kg, the rate of residueover criterion decreased from 8.3% to 0 .In the same times before theapplication and after the application, the residues of quinolones were0.071mg/kg, 0.067mg/kg, and the rates of residue over criterion were 10.4%,8.3%; the residues ofdoxycyclines were 0.110mg/kg, 0.092mg/kg, and therates of residue over criterion were 8.3%, 6.3%. Therefore , it is siginificantfor the application of the key controls.