The Pharmacodynamics Of Tilmicosin Phosphate On The Artifical Mycoplasmosis Infected Chickens And Its Safety To Chickens

Tilmicosin is a kind of semisynthetic macrolide antibiotics special for livestock and poultry.The antibacterial activity of tilmicosin to all kinds of gram-positive bacteria,some kinds of gram-negative bacteria,mycoplasma and spirochete is excellent.Since the high sensitivity to Mycoplasma pneumonia in livestock and poultry,tilmicosin was widely used in the treatment of livestock and poultry pneumonia.However,tilmicosin is insoluble in water,which leads to the limitation and inconvenient for veterinary usage in clinic.Tilmicosin phosphate is a compound which adds a phosphate group to tilmicosin but has better water-solubility.Tilmicosin is the effective component of tilmicosin phosphate aqueous solution.The pharmacodynamics experiment in vivo and vitro and the safety experiment were done to provide the scientific evidence for clinical using of 10%tilmicosin phosphate soluble powder on chickens.To evaluate the antibacterial activity of tilmicosin in vitro,micro dilution method was used to test the minimal inhibitory concentration(MIC)of 9 kinds of microbes,which indicates the effects of several antibiotics including tilmicosin phosphate.The results showed that the antibacterial activity was very excellent of tilmicosin phosphate to Mycoplasma hyopneumoniae,Mycoplasma gallisepticum,Actinobacillus pleuropneumoniae,Streptococcus suis,Haemophilus parasuis and other commonly pathogenic bacteria of domestic animals.The MIC of tilmicosin phosphate to Mycoplasma hyopneumoniae and Mycoplasma gallisepticum respectively are 0.3125ccu/mL and 0.0049ccu/mL,to other pathogenic bacteria is 0.0049-2.5?g/mL.Compared to timicosin,tilmicosin phosphate has better solubility in the water.The treatment effects of different dosage of 10%tilmicosin phosphate soluble powder were studied by texting the pulmonary lesion score and other indexes of chickens in the artificial infection model of chicken mycoplasmosis disease in this experiment.The results showed that the therapeutic effects by using 60-80 mg/L dosage of 10%tilmicosin phosphate soluble powder were the same as those of 10%tilmicosin soluble powder(75 mg/L in water,counted with tilmicosin),and the cure rate and utility rate can be 70%and 100%for curing the chicken mycoplasmosis disease.It is convenient for tilmicosin phosphate to be clinically used in the future because of the increasing water solubility by adding the phosphate group.To evaluate the safety of clinical using of tilmicosin phosphate soluble powder,different dosages of tilmicosin phosphate soluble powder were given to the tested chickens.Blood biochemical indexes,coagulation tests,blood cell contents,routine urine indexes were tested and histopathological examinations were done to evaluate the clinical safety of tilmicosin phosphate soluble powder on chickens.The results showed that decuple the dosage of 800mg/mL tilmicosin phosphate soluble powder did not show any bad effects on tested chickens.No significant pathological changes were observed in the histopatholological examination,the safety of tilmicosin phosphate soluble powder on tested chickens under the dosage of 800mg/mL was certified.