七种常用渔药及组合对罗非鱼致病性海豚链球菌的体外抗菌试验

The antibacterial trial of seven kind common fishery drugs and their combinations to pathogenic Streptococcus iniae from tilapia

关键词:  罗非鱼  海豚链球菌  渔用药物  最小抑菌浓度

Key words:  tilapia  Streptococcus iniae  fishery drugs  MIC

摘要:

探讨了7种常用抗菌渔药对罗非鱼致病性海豚链球菌的体内外抗菌作用。采用二倍稀释法测定了7种渔药对致病菌的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）；在初筛基础上以MIC为单位，1譓IC、5譓IC、10譓IC和20譓IC下平板抑菌圈直径为参数，分别比较所筛选5种药物抗菌效果并优化最佳参数；利用优化的最佳参数比较5种药物单独用药与联合用药对海豚链球菌的抑菌效果；并通过拌饵投喂给药方式对罗非鱼进行5种药物治疗性给药试验。结果表明，抗菌先锋对海豚链球菌的MIC和MBC最小，分别为6.4和12.8 礸/mL，其次是伯乐立康，均为12.8 礸/mL；而鱼康和肠炎烂鳃灵即使在1638.4 礸/mL下也无抗菌效果。5倍MIC下抑菌圈直径为本实验筛选抗菌药物的最佳参数。5MIC时，海豚链球菌对伯乐立康和抗菌先锋敏感，对菌必清、菌毒康和海鱼安中度敏感。菌毒康与海鱼安的联合抗菌效果最佳。鱼体内抗菌试验结果表明，抗菌先锋和伯乐立康的治疗有效率超过75%，达到了理想的治疗效果，是防治罗非鱼海豚链球菌病的首选药物。

Abstract:

The antibacterial effect of 7 common fish drugs on pathogenic Streptococcus iniae from tilapia in vivo and vitro was studied in this paper. The minimum inhibitory concentrations and the minimal bactericidal concentrations of 7 fish drugs were tested by the method of doubling dilution in test tube. On the basis of preliminary screening, comparing the inhibiting and anti-bactericidal effects of 5 fish drugs on Streptococcus iniae respectively in the inhibition circles of 1? 5? 10?and 20?MICs by using MIC as a unit, the best parameter was obtained. Then, the best parameter was applied to compare the inhibiting effects of 5 fishery drugs in single and their combination. The anti-bacterial trial in vivo for tilapia was performed by remedial administer drugs mixed with feed. The results showed that the MIC and MBC of ET was mixmum (6.4 礸/mL and 12.8 礸/mL), and then which of GCHBH were all 12.8 礸/mL, but CSP and NSP had no inhibitory effects even at concentration of 1638.4 礸/mL. The inhibition circle of 5譓IC was the best parameter. Under the parameter, Streptococcus iniae was the most sensitive to ET and GCHBH, and followed by EP, FP and DHP. The combination of FP and DHP had the best antibacterial effect. Results of antibacterial test for tilapia in vivo with 5 fishery drugs indicated that the curative ratio effectively of ETSP and GCHBH all exceeded 75%. So the two fishery drugs displayed good treatment effect, which were the first choice antibiotics in prevention and treatment on pathogenic Streptococcus iniae from tilapia.