Naidoo V, Taggart M A, Duncan N, Wolter K, Chipangura J, Green R E, Galligan T H
Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, South Africa; Biomedical Research Centre, Faculty of Veterinary Science, University of Pretoria, South Africa.
Environmental Research Institute, University of the Highlands and Islands, Castle St, Thurso, Scotland, KW17 7JD, UK.
Chemosphere. 2018 Jan;190:80-89. doi: 10.1016/j.chemosphere.2017.08.167. Epub 2017 Sep 14.
Veterinary medicines can be extremely damaging to the environment, as seen with the catastrophic declines in Gyps vulture in South Asia due to their secondary exposure to diclofenac in their primary food source. Not surprisingly, concern has been raised over other similar drugs. In this study, we evaluate the toxicity of carprofen to the Gyps vulture clade through plasma pharmacokinetics evaluations in Bos taurus cattle (their food source) and Gyps africanus (a validated model species); tissue residues in cattle; and the effect of carprofen as a secondary toxicant as both tissue-bound residue or pure drug at levels expected in cattle tissues. Carprofen residues were highest in cattle kidney (7.72 ± 2.38 mg/kg) and injection site muscle (289.05 ± 98.96 mg/kg of dimension of 5 × 5 × 5 cm). Vultures exposed to carprofen as residues in the kidney tissue or pure drug equivalents showed no toxic signs. When exposed to average injection site concentrations (64 mg/kg) one of two birds died with evidence of severe renal and liver damage. Toxicokinetic analysis revealed a prolonged drug half-life of 37.75 h in the dead bird as opposed to 13.99 ± 5.61 h from healthy birds dosed intravenously at 5 mg/kg. While carprofen may generally be harmless to Gyps vultures, its high levels at the injection site in treated cattle can result in lethal exposure in foraging vultures, due to relative small area of tissue it is found therein. We thus suggest that carprofen not be used in domesticated ungulates in areas where carcasses are accessible or provided to vultures at supplementary feeding sites.
兽药可能会对环境造成极大破坏，正如在南亚，由于兀鹫在其主要食物来源中二次接触双氯芬酸，导致其数量灾难性下降。毫不奇怪，人们对其他类似药物也提出了担忧。在本研究中，我们通过对黄牛（它们的食物来源）和非洲白背兀鹫（一种经过验证的模型物种）进行血浆药代动力学评估；检测牛体内的组织残留；以及评估卡洛芬作为组织结合残留或纯药物形式的二次毒物，在牛组织中预期水平下的影响，来评估卡洛芬对兀鹫类的毒性。卡洛芬在牛肾脏中的残留量最高（7.72±2.38毫克/千克），在注射部位肌肉中的残留量为（尺寸为5×5×5厘米的肌肉中为289.05±98.96毫克/千克）。接触肾脏组织中卡洛芬残留或纯药物等效物的兀鹫未表现出中毒迹象。当接触平均注射部位浓度（64毫克/千克）时，两只鸟中有一只死亡，有严重肾损伤和肝损伤的迹象。毒代动力学分析显示，死亡鸟体内药物半衰期延长至37.75小时，而静脉注射5毫克/千克的健康鸟的半衰期为13.99±5.61小时。虽然卡洛芬通常可能对兀鹫无害，但在接受治疗的牛的注射部位其含量很高，由于在该部位发现卡洛芬的组织面积相对较小，可能会导致觅食的兀鹫致命接触。因此，我们建议在尸体可被兀鹫获取或在补充喂食点提供给兀鹫的地区，不要在驯养有蹄类动物中使用卡洛芬。
