Cunningham Fred, Dean Karen, Hanson-Dorr Katie, Harr Kendal, Healy Kate, Horak Katherine, Link Jane, Shriner Susan, Bursian Steven, Dorr Brian
USDA/ APHIS/ Wildlife Services/National Wildlife Research Center, Starkville, MS, United States.
Abt Associates, Boulder, CO, United States.
Ecotoxicol Environ Saf. 2017 Jul;141:199-208. doi: 10.1016/j.ecoenv.2017.03.025. Epub 2017 Mar 27.
Oral and external dosing methods replicating field exposure were developed using the double crested cormorant (DCCO) to test the toxicity of artificially weathered Deepwater Horizon Mississippi Canyon 252 oil. The majority of previous oil dosing studies conducted on wild-caught birds used gavage methods to dose birds with oil and determine toxicity. However, rapid gut transit time of gavaged oil likely reduces oil absorption. In the present studies, dosing relied on injection of oil into live feeder fish for oral dosing of these piscivorous birds, or applying oil to body contour feathers resulting in transdermal oil exposure and oral exposure through preening. Both oral and external oil dosing studies identified oil-related toxicity endpoints associated with oxidative stress such as hemolytic anemia, liver and kidney damage, and immuno-modulation or compromise. External oil application allowed for controlled study of thermoregulatory stress as well. Infrared thermal images indicated significantly greater surface temperatures and heat loss in treated birds following external oil applications; however, measurements collected by coelomically implanted temperature transmitters showed that internal body temperatures were stable over the course of the study period. Birds exposed to oil externally consumed more fish than control birds, indicating metabolic compensation for thermal stress. Conversely, birds orally dosed with oil experienced hypothermia and consumed less fish compared to control birds.
采用双冠鸬鹚（DCCO）开发了模拟野外暴露的口服和外部给药方法，以测试人工风化的深水地平线密西西比峡谷252号原油的毒性。以前对野生捕获鸟类进行的大多数原油给药研究使用灌胃法给鸟类投喂原油并确定毒性。然而，灌胃原油在肠道内的快速通过时间可能会减少原油吸收。在本研究中，给药依赖于将油注射到活的饲料鱼中，以便对这些食鱼鸟类进行口服给药，或者将油涂抹在身体轮廓羽毛上，从而导致经皮接触油并通过梳理羽毛导致口服接触。口服和外部原油给药研究均确定了与氧化应激相关的原油毒性终点，如溶血性贫血、肝和肾损伤以及免疫调节或免疫损害。外部涂抹油还允许对体温调节应激进行对照研究。红外热成像表明，在外部涂抹油后，处理过的鸟类表面温度显著升高且热量损失更大；然而，通过腹腔植入的温度传感器收集的测量结果表明，在研究期间内，鸟类的体内温度保持稳定。与对照鸟类相比，外部接触油的鸟类消耗的鱼更多，这表明对热应激有代谢补偿。相反，与对照鸟类相比，口服原油的鸟类体温过低且消耗的鱼更少。
