Studies on the Control of Bombyx mori Bacterial Septicemia with Sarafloxacin Hydrochloride Capsules

WANG Yu-Hua 1,2 HE Rong-Fan2 KANG Guo-Ping1,2 LIU Ting1,2 WANG Juan2 XU Qin-Wen1,2 ZHONG Kui1,2(1Jiangsu University of Science and Technology,Zhenjiang Jiangsu 212003,China; 2The Sericultural Research Institute,Chinese Academy of Agricultural Sciences,Zhenjiang Jiangsu 212018,China)

Antibacterial agent for silkworm rearing; Sarafloxacin hydrochloride; Bacterial septicemia; Control effect; Safety; Pharmacokinetics

Sarafloxacin hydrochloride capsule is an antibacterial agent for silkworm (Bombyx mori) rearing and its main composition is veterinary quinolones sarafloxacin hydrochloride.The control effect on silkworm septicemia caused by Bacillus thuringiensis var.sotto Ishiwata (Bt) through continuous administration of 100 mg/L sarafloxacin hydrochloride for 3 d (administration for 24 h at day 1 and 6 h each at day 2 and day 3) to newly exuviated larvae of the 4th instar had no significant difference as compared with 500 mg/L norfloxacin hydrochloride and 125 mg/L ciprofloxacin hydrochloride (P>0.05).The control effect on silkworm septicemia caused by Serratia marcescens Bizio (Sm) through continuous administration of 400 mg/L sarafloxacin hydrochloride for 3 d (the administration timetable was same to the above) to newly exuviated larvae of the 4th instar was significantly better than that of 500 mg/L norfloxacin hydrochloride and 250 mg/L ciprofloxacin hydrochloride (P<0.05),but was not significantly different as compared with 500 mg/L ciprofloxacin hydrochloride (P>0.05).The minimum inhibitory concentrations of sarafloxacin hydrochloride on Bt and Sm was 1.25 and 5 μg/mL,respectively,while their minimum bactericidal concentrations were 5 and 10 μg/mL,respectively.Toxicity tests to sarafloxacin hydrochloride capsules showed that there was no significant effect on silkworm growth and development,cocoon quality and silk quality after administration of 400,800,1 200,and 2 000 mg/L sarafloxacin hydro-chloride to 4th and 5th instar larvae (t-test,P>0.05),respectively,and no significant dose-response relationship was observed between them.The drug had good absorption inside the larval body and the pharmacokinetic process fitted to the primary absorption kinetics and one compartment model after administration of 5,10 and 20 mg/kg sarafloxacin hydrochloride at day 4 of the 5th instar,respectively.The above results indicated that sarafloxacin hydrochloride capsules have satisfactory control effect against silkworm septicemia caused by Bt and Sm and have no adverse effect to silkworm.