title: Development of methods for avian oil toxicity studies using the double crested cormorant (Phalacrocorax auritus).
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.
authors.affiliation: USDA/ APHIS/ Wildlife Services/National Wildlife Research Center, Starkville, MS, United States. Electronic address: Fred.L.Cunningham@aphis.usda.gov.
authors.forename: Fred
authors.initials: F
authors.lastname: Cunningham
authors.affiliation: Abt Associates, Boulder, CO, United States.
authors.forename: Karen
authors.initials: K
authors.lastname: Dean
authors.affiliation: USDA/ APHIS/ Wildlife Services/National Wildlife Research Center, Starkville, MS, United States.
authors.forename: Katie
authors.initials: K
authors.lastname: Hanson-Dorr
authors.affiliation: Urika Pathology LLC, Mukilteo, WA, United States.
authors.forename: Kendal
authors.initials: K
authors.lastname: Harr
authors.affiliation: US Fish and Wildlife Service, Deepwater Horizon NRDAR Field Office, Fairhope, AL, United States.
authors.forename: Kate
authors.initials: K
authors.lastname: Healy
authors.affiliation: USDA/ APHIS/Wildlife Services/National Wildlife Research Center, Ft. Collins, CO, United States.
authors.forename: Katherine
authors.initials: K
authors.lastname: Horak
authors.affiliation: Department of Animal Science, Michigan State University, East Lansing, MI, United States.
authors.forename: Jane
authors.initials: J
authors.lastname: Link
authors.affiliation: USDA/ APHIS/Wildlife Services/National Wildlife Research Center, Ft. Collins, CO, United States.
authors.forename: Susan
authors.initials: S
authors.lastname: Shriner
authors.affiliation: Department of Animal Science, Michigan State University, East Lansing, MI, United States.
authors.forename: Steven
authors.initials: S
authors.lastname: Bursian
authors.affiliation: USDA/ APHIS/ Wildlife Services/National Wildlife Research Center, Starkville, MS, United States.
authors.forename: Brian
authors.initials: B
authors.lastname: Dorr
mesh_terms: D000279:Administration, Cutaneous; D000284:Administration, Oral; D000818:Animals; D001717:Birds / Q000097:blood / Q000378:metabolism* / Q000502:physiology; D001833:Body Temperature Regulation / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000633:toxicity*; D005241:Feathers / Q000187:drug effects / Q000502:physiology; D010578:Petroleum / Q000633:toxicity*
chemical_list: D004785:Environmental Pollutants; D010578:Petroleum
keywords: Deepwater Horizon; Double crested cormorant; External oil exposure; Internal oil exposure; Methods development; Oil toxicity