| A lot of studies showed that adding antibiotics into feed can enhance the productivity of animals and feed conversion rate and decrease the mortality and morbidity of animals which brings great economic benefit for livestock and poultry industry.Chlortetracycline is one of tetracyclines drugs and mainly inhibits the protein synthesis of sensitive microbial.Chlortetracycline is of wide antibiotic spectrum,including gram positive bacteria,gram negative bacteria,spirochete,mycoplasma,chlamydia,rickettsia,part of protozoa.Chlortetracycline is more sensitive to 70S ribosome.Therefore,Chlortetracycline can selectively inhibit sensitive microbial with well safety.So,in this study we explore the application of Chlortetracycline in chickens including the growth performance.We also conduct the determination of Chlortetracycline residues in chickens and the pharmacokinetics study,which will be useful to instruct the application of Chlortetracycline in chickens.The main results are shown below.1 The influence of Chlortetracycline on the growth performance of chickensIn the study,1200 AA broilers(600♂ +600♀)were randomly divided into five groups according to the weight.The treatment 4 groups containing respectively 50ppm Chlortetracycline premix(group 1),50ppm Chlortetracycline premix+Acid(?)digestion acid type I3kg/t(group 2),50ppm Chlortetracycline premix+ 50ppm Macleaya cordata(group 3),20%chlortetracycline hydrochloride(group 4)and the blank control group(group 5)containing no antibiotics were feed for the chickens.Measure and compare the rate of survival,daily gain and feed/gain ratio of the five groups.The results showed that adding Chlortetracycline into the feed can enhance the disease-resistant ability of chickens and significantly increase the rate of survival.Additionally,the rate of survival of group 1,2,3,4 was increased in sequence which means Chlortetracycline hydrochloride is better than Chlortetracycline premix,Chlortetracycline premix combining with Macleaya cordata is more effective than Chlortetracycline premix combining with Acid(?)digestion acid.The daily gain results showed that Chlortetracycline as feed additive is necessary for maintaining the normal productivity of chickens and Chlortetracycline hydrochloride seems more effective than Chlortetracycline premix.Chlortetracycline premix combining with Macleaya cordata is both better than either Chlortetracycline premix or Chlortetracycline premix combining with Acid(?)digestion acid.For the feed/gain ratio,Chlortetracycline can decrease the feed/gain ratio as feed additive,but there is no significant difference between the four groups.2The determination of Chlortetracycline residues in chickensIn this study,high performance liquid chromatography is applied to detect the concentration of Chlortetracycline in tissues and construct standard curve and high performance liquid chromatography-tandem mass is used to test the concentration of Chlortetracycline in blood.Standard curve was successfully constructed as Y=0.04739662x-0.2356354,R2=0.99988,with the detecting limit of 2.08 ng/mL and recovery rate 96.98%.The results showed that Chlortetracycline is metabolize through liver and maintained high level after drug discontinuance.The concentration of Chlortetracycline after 5 days of drug discontinuance is with no significant difference with that of the beginning of feeding.The results also suggested that Chlortetracycline is extracted through intestine other than kidney.The concentration of Chlortetracycline in muscle is lower than that in other tissues with rapid decrease after drug discontinuance.The concentration of Chlortetracycline in adipose is also lower than that in liver and kidney with so significant difference after drug discontinuance which is closely related to the poor adipose tissue metabolism.The residue of Chlortetracycline premix or chlortetracycline hydrochloride 50ppm as feed supplement is lower than that required by government and will decrease to different extent after 5 days drug discontinuance.3The pharmacokinetic study of Chlortetracycline in chickensIn this study,high performance liquid chromatography is applied to detect the concentration of Chlortetracycline in faces and high performance liquid chromatography-tandem mass is used to test the concentration of Chlortetracycline in blood.The results suggested that the bioavailability of chlortetracycline hydrochloride is 10 to 20 bolds higher when compared to Chlortetracycline premix.And Acid(?)digestion acid extends Chlortetracycline premix’s the time to peak and enhance Chlortetracycline premix’s bioavailability more than one time.For chlortetracycline hydrochloride,when compared to water,mixing materials doubles Chlortetracycline’ the time to peak and enhances the concentration of Chlortetracycline in blood more than ten times,which may be related to the slow-release of Chlortetracycline by feed package.Six days after administration Chlortetracycline can still be detected with low concentration. |
PDF Full Text Request