Pharmacokinetics of Some Synthetic Triazine Anticoccidials in Apparently Healthy North Island Brown Kiwi (Apteryx mantelli) Chicks.

Captive-reared kiwi (Apteryx spp.) chicks commonly suffer from coccidiosis, a parasitic disease that can cause morbidity and mortality in young immune-naive birds. Disease is currently managed in captivity through a combination of preventative husbandry practices and therapeutic treatment with the coccidiocide toltrazuril, for which no safety or pharmacokinetic data is available for kiwi. In this study we attempted to determine the pharmacokinetics of synthetic triazine anticoccidials, toltrazuril and diclazuril, in healthy three-to-four-week-old North Island brown kiwi (Apteryx mantelli) chicks. Birds were given a single oral dose of toltrazuril (25 mg/kg.bw; n = 6) or diclazuril (5 mg/kg.bw; n = 6), and closely monitored for adverse reactions. Serial blood samples were analysed via liquid chromatography-mass spectrometry (LC-MS) to determine the pharmacokinetics of both drugs, including the active metabolite of toltrazuril, toltrazuril sulphone. Pharmacokinetics were ascertained for both drugs in kiwi chicks. The mean (standard deviation) Cmax of diclazuril in plasma was 539.48 ± 169.63 ng/mL with a Tmax of 11.33 ± 1.63 h, while the Cmax for toltrazuril was 5622.16 ± 1997.52 ng/mL with a Tmax of 11.33 ± 1.63 h and Cmax of toltrazuril sulphone 3623.01 ± 1085.71 ng/mL with a Tmax of 96 ± 26.29 h. Mild changes to some biochemical parameters were observed, most notably elevations in uric acid in some toltrazuril-treated birds; however no remarkable clinical changes were observed in any chicks dosed with the drugs trialled.