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Variation in postsampling treatment of avian blood affects ecophysiological interpretations
Article first published online: 1 JUL 2011
© 2011 The Author. Methods in Ecology and Evolution © 2011 British Ecological Society
Methods in Ecology and Evolution
Volume 3, Issue 1, pages 162–167, February 2012
How to Cite
Hoye, B. J. (2012), Variation in postsampling treatment of avian blood affects ecophysiological interpretations. Methods in Ecology and Evolution, 3: 162–167. doi: 10.1111/j.2041-210X.2011.00135.x
- Issue published online: 1 FEB 2012
- Article first published online: 1 JUL 2011
- Received 14 December 2010; accepted 1 June 2011 Handling Editor: Robert Freckleton
- blood sampling;
- discrimination factor;
- stable isotopes;
1. The fluid component of blood is widely used in ecophysiological investigations, including measures of immune function and stable isotope ecology. After blood collection, delayed separation of blood extracellular fluids from red blood cells is known to affect the concentration of a wide range of biochemical compounds in the resulting fluid, as does prevention of clotting (producing plasma) when compared with blood allowed to clot (producing serum).
2. One challenge when investigating immune function and stable isotope ecology, therefore, is discriminating variation because of the effect of the biological factors of interest from potential methodological artefacts. This study assesses how seven widely used measures of immune function and stable isotope composition respond both to delayed separation of the cellular and fluid components and to the clotting of blood samples from two species of waterfowl.
3. Samples that remained uncentrifuged for up to 12 h did not differ from those centrifuged within 15 min of sampling from the same individuals, indicating that samples from a wide range of field conditions may remain highly comparable. However, the outcome of three of the four immunological assays and two of the three isotopic analyses was highly dependent on the type of fluid, with higher immunological activity and higher relative concentrations of heavy carbon and total nitrogen in plasma compared to serum.
4. Researchers interested in immune function and stable isotope ecology may obtain the most useful results by ensuring that they use a single fluid type in their investigations.