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Evaluation of anticoagulant rodenticide sensitivity by examining in vivo and in vitro responses in avian species, focusing on raptors

December 5, 2023

Anticoagulant rodenticides (ARs) are used to control pest rodent species but can result in secondary poisoning of non-target animals, especially raptors. In the present study, differences in AR sensitivity among avian species were evaluated by comparing in vivo warfarin pharmacokinetics and effects, measuring cytochrome P450s (CYPs) expression involved in AR metabolism, and conducting in vitro inhibition assays of the AR target enzyme Vitamin K 2,3-epoxide reductase (VKOR). Oral administration of warfarin at 4 mg/kg body weight did not prolong prothrombin time in chickens (Gallus gallus), rock pigeons (Columba livia), or Eastern buzzards (Buteo japonicus). Rock pigeons and buzzards exhibited shorter plasma half-life of warfarin compared to chickens. For the metabolite analysis, 4′-hydroxywarfarin was predominantly detected in all birds, while 10-hydroxywarfarin was only found in pigeons and raptors, indicating interspecific differences in AR metabolism among birds likely due to differential expression of CYP enzymes involved in the metabolism of ARs and variation of VKOR activities among these avian species. The present findings, and results of our earlier investigations, demonstrate pronounced differences in AR sensitivity and pharmacokinetics among bird species, and in particular raptors. While ecological risk assessment and mitigation efforts for ARs have been extensive, AR exposure and adverse effects in predatory and scavenging wildlife continues. Toxicokinetic and toxicodynamic data will assist in such risk assessments and mitigation efforts.

Publication Year 2024
Title Evaluation of anticoagulant rodenticide sensitivity by examining in vivo and in vitro responses in avian species, focusing on raptors
DOI 10.1016/j.envpol.2023.122837
Authors Kraisiri Khidkhan, Fuyu Yasuhira, Aksorn Saengtienchai, Chaiyan Kasorndorkbua, Ratiwan Sitdhibutr, Kohei Ogasawara, Hikaru Adachi, Yukiko Watanabe, Keisuke Saito, Hidefumi Sakai, Kazuo Horikoshi, Hajime Suzuki, Yusuke K. Kawai, Kazuki Takeda, Yared B. Yohannes, Yoshinori Ikenaka, Barnett A. Rattner, Mayumi Ishizuka, Shouta M.M. Nakayama
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Pollution
Index ID 70250377
Record Source USGS Publications Warehouse
USGS Organization Eastern Ecological Science Center
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