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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Vet. Sci. | doi: 10.3389/fvets.2019.00405

Effects of external oiling and rehabilitation on hematological, biochemical, and blood gas analytes in Ring-billed Gulls (Larus delawarensis)

 Nicholas G. Dannemiller1, 2*, Katherine E. Horak1, Jeremy W. Ellis1,  Nicole L. Barrett1, Lisa L. Wolfe3 and Susan A. Shriner1
  • 1National Wildlife Research Center, Animal and Plant Health Inspection Service, United States
  • 2Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, United States
  • 3Other, United States

Avian species experience extensive morbidity and mortality following large-scale oil spills, often resulting in oiled birds being rescued and admitted to rehabilitation. Our objective was to experimentally establish time-specific, descriptive blood analyte data following sublethal oil exposure and subsequent rehabilitation. Thirty wild Ring-billed Gulls (Larus delawarensis) were randomly allocated to three treatment groups of 10 birds each. One treatment group served as controls and two treatment groups were externally oiled daily for three days with weathered MC252 oil collected from the Deepwater Horizon oil spill, mimicking the upper threshold of the US Fish and Wildlife Service’s moderate oiling classification. Following external oiling, one oiled treatment group was cleaned via standard rehabilitation practices. Serial venous blood samples were collected for a month to measure packed cell volume, total solids, blood gas and select plasma biochemistry analytes, total white blood cell estimates and differentials, and reticulocyte estimates. We found that both sublethal oil exposure and aspects of captivity were associated with a mild non-regenerative anemia. No other differences in venous blood gas and biochemical analytes as well as white blood cell concentrations were observed among the three groups. These findings suggest that the mild anemia seen in oiled birds undergoing rehabilitation is possibly multifactorial and that moderately oiled gulls have subtle, but potentially not insignificant clinicopathological abnormalities following sublethal oil exposure. Oiled gulls did not develop any clinicopathological derangements post-rehabilitation, suggesting current standard practices for rehabilitation cause minimal morbidity in clinically stable, moderately oiled gulls.

Keywords: Larus delawarensis, immune suppression, hemolytic anemia, wildlife rehabilitation, Blood gas, Oil toxicity

Received: 12 Jun 2019; Accepted: 31 Oct 2019.

Copyright: © 2019 Dannemiller, Horak, Ellis, Barrett, Wolfe and Shriner. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mr. Nicholas G. Dannemiller, National Wildlife Research Center, Animal and Plant Health Inspection Service, Fort Collins, 80521, Colorado, United States,