| Neomycin sulphate is a kind of aminoglycoside antibiotics.It is widely used in animal husbandry because it has many advantages,such as strong stability,low price,and promotion.Also,it is one of the first choice drugs for the treatment of intestinal infection in livestock and poultry.White scour of piglets is an acute intestinal infectious disease caused by pathogenic Escherichia coli.If it is not treated in time,it will seriously restrict the growth and development of piglets.Currently,the marketed neomycin sulphate soluble powder’s target animals is only chicken,used to treat gastrointestinal infections caused by Gram-negative bacteria,and there is no research about pigs.Therefore,we have a preliminary study about the pharmacodynamics of neomycin sulphate soluble powder treating white scour of piglets,target animal safety evaluation and residues of neomycin sulphate soluble powder in pigs.This study includes the following:1 The pharmacodynamics of neomycin sulphate soluble powder in piglets with artificially infected white scourIn this study,we aim to investigate the therapeutic effect of neomycin sulphate soluble powder on the white scour of piglets caused by artificial infection,and to provide a reference dose for Phase Ⅲ clinical trial.Refer to the Compendium of Technical Guidelines for Veterinary Drug Research issued by the Ministry of Agriculture.Piglets of 4-6 days old were selected and infected with Enterotoxigenic E.coil（CVCCC196 strain）to establish the model of white scour of piglets caused by artificial infection,and set low dose group（0.012 g·kg-1）,middle dose group（0.024 g·kg-1）,high dose group（0.047 g·kg-1）,positive control group,blank control group and drug control groups（apramycin sulphate soluble powder group）.The therapeutic effects of each group were comprehensively determined by indicators such as clinical symptoms and body weight.The results showed that the model of white scour of piglets could be successfully established with the appropriate stress by filling 60×109 CFU/head dose Escherichia coli（CVCC196）.Piglets administering high and medium dose of the neomycin sulphate soluble powder recovered in the mental condition,appetite,feces condition and weight gain.The cure rate and effective rate are both 90%,and the treatment effect is better than that of control drug the apramycin sulfate soluble powder（the cure rate and the effective rate are 50%,60%）.The neomycin sulfate soluble powder has a good therapeutic effect on the white scour of piglets caused by artificial infection at a clinically recommended dose of 0.024 g·kg-1 for 5 days,and has no adverse reactions,and can be extended to clinical trials.2 The pharmacodynamics of neomycin sulphate soluble powder in piglets with naturally infected white scourTo investigate the therapeutic effect of neomycin sulphate soluble powder on the white scour of piglets caused natural infection.156 cases of typical white scour of piglets were selected by clinical symptoms and laboratory pathogens,and were randomly divided into two groups,neomycin sulfate soluble powder group（0.024 g·kg-1）and apramycin sulfate soluble powder group（0.125 g·kg-1）,respectively.The therapeutic effects of each group were comprehensively determined by indicators such as clinical symptoms and body weight.Piglets administering the clinical recommended dose（0.024 g·kg-1）of the neomycin sulfate soluble powder for 5 days can be cured quickly.The cure rate is 91.89%,the effective rate is 97.30%,and the average course of treatment is 2.87 days,and the treatment effect is better than that of control drug the apramycin sulfate soluble powder（the cure rate was 82.19%,the effective rate was 90.41%,and the average course of treatment was 4.05 d）.In conclusion,the neomycin sulphate soluble powder was administered at a clinically recommended dose（0.024 g·kg-1）for 5 days,which has a good effect on white scour of piglets caused by natural infection,and has no adverse reactions.3 The safety evaluation of neomycin sulfate soluble powder on target animal pigletsIn order to evaluate the safety of neomycin sulfate soluble powder on piglets,32 piglets were randomly divided into 4 groups according to the "Guidelines for VICH Veterinary Drug Target Animal Safety Research",which were 1 times（0.024 g·kg-1）,3 times（0.072 g·kg-1）,5 times（0.120 g·kg-1）clinical recommended dose group and the blank control group,and piglets were administered with neomycin sulphate soluble powder for 15 days.The clinical manifestations,blood physiology and biochemistry,urine routine,anatomy and histopathology of each group of animals were detected to evaluate the safety of neomycin sulphate soluble powder on piglets.The results showed that the clinical manifestations of each groups were normal during the trial period,which showed good mental state,free movement and strong appetite.There were no significant difference of urine routine indexes,anatomy and histopathology among these groups.Only the blood physiological and biochemical indexes of individual piglets showed significant changes compared with the control group,but they were all normal.In conclusion,the neomycin sulphate soluble powder is safety for piglets within 5 times the clinical recommended dose.4 Residues of neomycin sulphate soluble powder in pigletsTo establish a method for detection of neomycin sulphate in edible tissues of piglets,and determine the withdrawal period for clinical application of neomycin sulphate soluble powder.20 piglets（about 45 kg）were randomly divided into 5 groups with neomycin sulphate soluble powder（0.024 g·kg-1）for 5 days,4 piglets were respectively slaughtered at 0,0.5,1,3,5 days.The content of drug in tissues was detected by ultra-performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）to study the residual law of neomycin sulphate in the edible tissues of piglets.The muscle,liver and kidney tissues were extracted with 0.01 M PBS and 10%aqueous solution of trichloroacetic acid（containing 0.4 mM Na2EDTA）,the adipose tissue was extracted with 10%trichloroacetic acid methanol solution,then purified by Oasis MCX solid-phase extraction cartridge and analyzed for UPLC-MS/MS.The results showed that the detection limit（LOD）and limit of quantitation（LOQ）of the method were 50 μg·kg-1 and 100 μg·kg-1,respectively;The method has a good linearity at the range of 100～20000 μg·kg-1,with related coefficient of 0.99.Recoveries of spiked samples ranged was from 83.07%and 103.38%with relative standard deviation（RSD）less than 10.65%,and the stability is good.The results of residue test showed that the content of neomycin sulphate in the tissues of the piglets after stopping administration for 24 hours was lower than the maximum residue limit,and lower than the limit of quantitation after stopping administration for 5 days.In this study,the ultra-performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）method for the determination of neomycin sulphate residues in edible tissues of piglets is successfully established,and the withdrawal period of neomycin sulphate soluble powder in piglets is 3 days. |
PDF Full Text Request