| Tilmicosin is a new special macrolide antibiotic for animal,which is often used in the treatment of respiratory tract infection caused by Pasteurella and Mycoplasma.“Veterinary Pharmacopoeia” and 《GB31650 Maximum Residue Limit for Veterinary drugs in Food》have clear provisions on the use of 10% Tilmicosin solution concentration and residues limit in chicken’s tissue and viscera.If improper use will cause drug residues of the chicken tissues and viscera exceed the standard,which causing food safety problems and economic losses.Therefore this research was conducted to investigate the relationship between the different drinking concentration of Tilmicosin solution and drug residues in various tissues and organs of chickens,so as to provide a reference of standardizing the clinic use of Tilmicosin solution and ensure food safety.According to the 0.75 m L/L concentration and the dosage was determined for 20 h prescribed by the “Veterinary Pharmacopoeia”,In the condition of the drinking time limitation,and feeding with Tilmicosin solution of different concentrations carried out.A total of 176,000 healthy white-feathered broilers from 11 to 12 days were selected and divided into 6 groups.The standard concentration of groups 1 and 5 was 0.75 m L /L,the standard concentration of groups 2 and 6 was 1.5 m L /L,the standard concentration of group 3 was 3 m L /L,and the standard concentration of group 4 was 6 m L /L.The health of chickens was observed before,during and after treatment(2.5 h,5 h,10 h,20 h),The centration of Tilmicosin in blood was detected at 15 h,18 h,24 h and 28 h after drug withdrawal.Tilmicosin residues in tissues and organs(liver,kidney,spleen,muscle and neck skin)of different groups were detected by LC/ MS-MS at 12 d,16 d and 20 d after drug withdrawal.The results showed that 6 groups of broilers with drinking concentrations were healthy and did not have drug poisoning.After 15 h,18 h,24 h and 28 h of drug withdrawal,the Tilmicosin concentration in blood of each group decreased gradually with the increase of drug withdrawal time,and the Tilmicosin concentration in blood of groups1-6 was 0.05±0.01 after 28 h,respectively.0.058±0.009;0.209±0.040;0.109±0.021;0.162±0.039;0.060±0.012;0.191±0.045(μg/m L),plasma concentration did not increase under the increase of drinking water concentration.After 12 d disuse in the experimental group,the highest residual Tilmicosin residual in tissues and organs was 145.5 μg/kg in liver,Renal 104.4 μg/kg in Renal;34.31 μg/kg in Spleen;5.5 μg /kg in Muscle;47.1μg /kg in Neck skin,which was well below the national residue limit.The residue showed a decreasing trend 16 days and 20 days after disuse.In conclusion,Tilmicosin solution of different concentrations range(0.75 m L /L～6 m L/L)at same dose has no toxic damage to white-feathered broilers.Under eight times the standard concentration,the Tilmicosin solution has little side effects on the targeted animal white-feathered broilers.Meanwhile it has a wide safety range and high safety in clinical use.Even if also Increasing drug concentration blindly(shortening drinking time)did not have more significant effect on blood drug concentration of white-feathered broilers.After the prescribed drug withdrawal period of 12 days,the veterinary drug residues in all tissues and organs met the national standards,and the food safety guarantee coefficient of Tilmicosin solution was high.If there is a risk of excessive residue of Tilmicosin in clinic,it can be solved by prolonging the withdrawal period.This study can be used as a guideline and reference for on-site medication and food safety control management by practicing veterinarians. |
PDF Full Text Request