Unusual patterns in 15N blood values after a diet switch in red knot shorebirds
Dietz, M.W.; Piersma, T.; Dekinga, A.; Korthals, H.; Klaassen, M. (2013). Unusual patterns in 15N blood values after a diet switch in red knot shorebirds. Isot. Environ. Healt. S. 49(2): 283-292. dx.doi.org/10.1080/10256016.2013.776045
In: Isotopes in Environmental and Health Studies. Taylor & Francis: Basel. ISSN 1025-6016; e-ISSN 1477-2639, more
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| Author keywords |
blood cells; diet switch; discrimination factor; nitrogen-15; plasma;regression model; shorebirds; turnover rate |
| Authors | | Top |
- Dietz, M.W.
- Piersma, T., more
- Dekinga, A., more
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- Korthals, H.
- Klaassen, M.
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| Abstract |
When a diet switch results in a change in dietary isotopic values, isotope ratios of the consumer's tissues will change until a new equilibrium is reached. This change is generally best described by an exponential decay curve. Indeed, after a diet switch in captive red knot shorebirds (Calidris canutus islandica), the depletion of C-13 in both blood cells and plasma followed an exponential decay curve. Surprisingly, the diet switch with a dietary N-15/N-14 ratio (N-15) change from 11.4 to 8.8 parts per thousand had little effect on N-15 in the same tissues. The diet-plasma and diet-cellular discrimination factors of N-15 with the initial diet were very low (0.5 and 0.2 parts per thousand, respectively). N-15 in blood cells and plasma decreased linearly with increasing body mass, explaining about 40 % of the variation in N-15. N-15 in plasma also decreased with increasing body-mass change (r(2)=.07). This suggests that the unusual variation in N-15 with time after the diet switch was due to interferences with simultaneous changes in body-protein turnover. |
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