Study On Prevention Of Silkworm Bacterial Diseases And Pharmacokinetics Of Levofloxacin

Silkworm bacteriosis have occurred in the sericulture production, bring the sericultural production serious harm. In this Paper, based on the in vitro bacteriostasis experiment, sceening a preferable drug-Levofloxacin to restrain Bacillus thuringiensis, Bacillus bombysepticus, Serratia marcescena Bizio from five kinds of commonly used veterinary antibiotics Levofloxacin, Enrofloxacin hydrochloride, Deoxytetracycline, Neomycin Sulphate and Florfenicol. The paper studiedthe control efficiency and the influence on silkworm,s growth and cocoon quality. Infected silkworms were studied following adding administration.The pharmacokinetic characteristics of Levofloxacin following adding administration were conducted with healthy and infceted silkworms by using microbiologic assay and the Ultra Performance Liquid Chromatography(UPLC).Application of DAS 2.0 analyze the change of drug concentration and time.In vitro antibacterial experiment results show that the three kinds of pathogenic bacteria are sensitive to Levofloxacin. For three kinds of pathogenic bacteria, the minimum bacteriostasis concentration is 0.19 μg/m L.The biological experiment results show that 1 000 μg/m L Levofloxacin for the treatment of bacterial poisoning, the efficient of prevention and control were 98.4% and 95.0% respectively;the Bacillus bombysepticus disease were 100% and 100%, is better than Florfenicol. Florfenicol is noneffective for the Serratia marcescena Bizio disease, and 1000 μg/mL Levofloxacin, the efficient of prevention and control were 85.0%, 75.0%. If adding mulberry leaf of Levofloxacin and interval time is shorter, the treatment effect is better. Adding mulberry leaf of Levofloxacin one time a day or the next day, had no significant influence for silkworm growth and cocoon quality(P > 0.05).The pharnacokinetics showed that the concentration-time course of Levofloxacin in plasma following adding Levofloxaxin in healthy silkworms can be deseribed by one-compartment open model with first order absorption,the main primary parameters were showen below: Ka 0.507±0.032 h-1,T1/2Ka 1.425±0.017 h,Tmax 5 h,Cmax 5.352±0.155 μg/mL. Explaining that the drug concentration is high, but the peak time is long, the rate of absorption is small, the process of slowly absorption and lasting,. The results are basically identical with the microbial method.But the elimination half-life is prolonged significant longer.The concentration-time course of Levofloxacin in plasma following adding administration in infected silkworms can be deseribed by two-compartment open model with first order absorption. Compared with the primary parameters in healthy silkworms, the changement of primary parameters was showen below: Ka decreases from 0.507 h-1 to 0.386 h-1, T1/2Ka increases from 1.425 h to 1.798 h, indicated that bacterial infection lead to the absorption of Levofloxacin is slower; AUC decreases from 38.770 μg/mL*h to 35.909 μg/mL*h, showed that bacterial infection lead to reduce for per unit time of drug concentration, the silkworm’s absorption; T1/2α decreases from 1.679 h to 1.483 h, T1/2β decreases from 4.922 h to 4.922 h, bacterial infection accelerate the distrubution and elimination; Cmax in the health and infected group, are 5.352 μg/mL and 4.977 μg/mL, that show the Levofloxacin can reach the highest drug concentration.