ABSTRACT

1. This study investigated the pharmacokinetics of metronidazole after intravenous (i.v.) and oral administration to healthy and experimentally Trichomonas gallinae-infected pigeons, and determined the in vitro antiprotozoal activity of metronidazole against T. gallinae.

2. Twelve pigeons which were experimentally infected to T. gallinae and twelve healthy pigeons received metronidazole at the dose of 25 mg/kg by oral or i.v. administration. Serial blood sampling was used for pharmacokinetic analysis. The metronidazole minimum lethal concentration (MLC) and the concentration killing 50% of the trophozoites (LC₅₀) in the culture media were determined.

3. In vitro data showed that the 24 h LC₅₀ and MLC of metronidazole were 0.31 and 25 µg/ml, respectively. In vivo results showed no statistical differences between pharmacokinetics in infected and non-infected pigeons for both routes of administration. The area under the curve was statistically higher after the i.v. administration in both infected and healthy pigeons. The mean oral bioavailability was similar in the infected (83.8%) and the healthy (81.5%) birds.

4. In conclusion, the pharmacokinetics of metronidazole in pigeons was not affected by experimentally-induced trichomoniasis. Despite in vitro susceptibility testing, which showed probable resistance of the isolated T. gallinae to metronidazole, five-day oral treatment of infected pigeons with 25 mg/kg metronidazole twice a day resulted in total eradication of trophozoites recovered in crop lavage of infected birds.

摘要

1. 本研究调查了甲硝唑在静脉注射 (iv) 和口服给药后对健康和实验性鸡毛滴虫感染的鸽子的药代动力学，并确定了甲硝唑对鸡毛滴虫的体外抗原生动物活性。

2.实验感染鸡T. 12只鸽子和12只健康鸽子口服或静脉注射25mg/kg剂量的甲硝唑。连续采血用于药代动力学分析。测定了培养基中的甲硝唑最小致死浓度（MLC）和杀死50%滋养体的浓度（LC ₅₀）。

3.体外数据显示，甲硝唑的 24 h LC ₅₀和 MLC 分别为 0.31 和 25 µg/ml。体内结果显示两种给药途径的感染和未感染鸽子的药代动力学之间没有统计学差异。感染和健康鸽子静脉注射给药后，曲线下面积在统计学上更高。受感染禽类 (83.8%) 和健康禽类 (81.5%) 的平均口服生物利用度相似。

4. 总之，甲硝唑在鸽子体内的药代动力学不受实验性滴虫病的影响。尽管体外药敏试验表明分离的鸡T. gallinae可能对甲硝唑有抗药性，但用25 mg/kg 甲硝唑每天两次对受感染的鸽子进行为期五天的口服治疗，导致完全根除受感染鸟类的作物灌洗液中回收的滋养体。