Development of methods for avian oil toxicity studies using the double crested cormorant (Phalacrocorax auritus)

Authors

Fred L. Cunningham, USDA/ APHIS/ Wildlife Services/National Wildlife Research CenterFollow
Karen Dean, Abt Associates
Katie C. Hanson-Dorr, USDA/APHIS/Wildlife Services/National Wildlife Research CenterFollow
Kendal Harr, Urika Pathology LLCFollow
Kate Healy, US Fish and Wildlife Service
Katherine E. Horak, USDA/APHIS/Wildlife Services/National Wildlife Research CenterFollow
Jane Link, Michigan State UniversityFollow
Susan A. Shriner, USDA/APHIS/WS National Wildlife Research CenterFollow
Steve J. Bursian, Michigan State UniversityFollow
Brian S, Dorr, USDA/APHIS/WS National Wildlife Research CenterFollow

Document Type

Article

Date of this Version

2017

Citation

Ecotoxicology and Environmental Safety 141 (2017) pp. 199–208.

Comments

U.S. government work.

Abstract

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.