黄胸鼠对溴敌隆抗药性的区分剂量测定及对其凝血反应的影响

Discrimination dose of bromadiolone and its effect on blood clotting response in resistant and susceptible buff-breasted rat Rattus flavipectus

目的明确凝血反应检测黄胸鼠对溴敌隆抗药性的方法,探讨其应用前景。方法通过摄食实验,以野外种群ED95的置信上限测定区分剂量,参照摄食实验区分抗性和敏感黄胸鼠,研究区分剂量对黄胸鼠凝血反应的影响。结果黄胸鼠对溴敌隆抗药性区分剂量为4.0mg/kg,以此区分剂量和20d后存活为标准筛选抗药性黄胸鼠。结果显示,抗药性种群在区分剂量作用下,凝血酶活动度(PCA)虽有所下降(下降幅度可达正常水平的17%),但可在2-3d内恢复到正常凝血水平;而敏感性黄胸鼠的凝血酶可下降到很低,且不能恢复。另外,区分剂量作用4d后,黄胸鼠PCA的种群分布从单峰型向双峰型分化,其中敏感亚种群的PCA在0～8.16之间,而抗药性亚种群则在10～100之间,此时黄胸鼠的PCA基本上可代表其20d内的存活率,也说明了凝血反应与摄食实验的一致性。结论以区分剂量4.0mg/kg溴敌隆作用后,PCA=10(或INR=5.0)作为阈值来区分黄胸鼠抗药性与敏感性个体,是准确、简便、易行的抗药性测定方法。

Objective To develop techniques to monitor the resistance of commensal rodents with blood clotting response （BCR） test. Methods Buff-breasted rats Rattus flavipectus were sampled from suburbs of Zhanjiang, Guangdong province, where higher resistance to bromadiolone had been documented previously. Results With non-alternative feeding tests, the upper limit of 95% effective dose of the wild population was proposed as discrimination dose（4.0 mg/kg） to discriminate the resistant buff-breasted rat form susceptible ones according to the method appraised by European and Mediterranean Plant Protection Organization （OEPP/EPPO, 1995 ）. And then, effects of bromadiolone at 4.0 mg/kg body weight on the blood clotting response of buff-breasted rat were studied. Results showed that the discrimination dose droved the percentage dotting activity（PCA） distribution pattern changed form one peak type of pre-treatment whole population into double peaks type, which one peak stand for resistant individuals which would survive within 20 d for their PCA range from 10-100, and the other peak should be susceptible individuals which would die in the following days for their PCA less than 10, which indicated the consistence of BCR method and non-alternative feeding test in monitoring the resistance of buff-breasted rat. Furthermore, both resistant and susceptible individuals decreased their PCA in the following days, while PCA of resistant individuals only decreased to 17 % of normal level and soon increased to normal level within 2-3 d, compared to that of susceptible individuals whose PCA decrease dramatically and no increase observed. Therefore, PCA= 10 （INR= 5.0 ） might be a threshold in determining ＂responders＂ to discriminate the resistant and susceptible rodent administrated by 4.0 mg/kg bromadiolone. Conclusion BCR might be applicable method to monitor the resistance against anticoagulant rodenticides of commensal rodents.