Journal article
The effect of dietary protein quality on nitrogen isotope discrimination in mammals and birds
Oecologia, Vol.144(4), pp.534-540
08/2005
Handle:
https://hdl.handle.net/2376/113881
PMID: 15800751
Abstract
We tested the competing hypotheses that (1) nitrogen discrimination in mammals and birds increases with dietary nitrogen concentration or decreasing C:N ratios and, therefore, discrimination will increase with trophic level as carnivores ingest more protein than herbivores and omnivores or (2) nitrogen discrimination increases as dietary protein quality decreases and, therefore, discrimination will decrease with trophic level as carnivores ingest higher quality protein than do herbivores. Discrimination factors were summarized for five major diet groupings and 21 different species of birds and mammals. Discrimination did not differ between mammals and birds and decreased as protein quality (expressed as biological value) increased with trophic level (i.e., herbivores to carnivores). Relationships between discrimination factors and dietary nitrogen concentration or C:N ratios were either the opposite of what was hypothesized or non-significant. Dietary protein quality accounted for 72% of the variation in discrimination factors across diet groupings. We concluded that protein quality established the baseline for discrimination between dietary groupings, while other variables, such as dietary protein intake relative to animal requirements, created within-group variation. We caution about the care needed in developing studies to understand variation in discrimination and subsequently applying those discrimination factors to estimate assimilated diets of wild animals.
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Details
- Title
- The effect of dietary protein quality on nitrogen isotope discrimination in mammals and birds
- Creators
- Charles Robbins - Department of Natural Resource Sciences and School of Biological Sciences Washington State University Pullman WA 99164-4236 USALaura Felicetti - Zoological Society of San Diego 120551 San Diego CA 92112-0551 USAMatt Sponheimer - Department of Anthropology University of Colorado at Boulder Boulder CO 80309 USA
- Publication Details
- Oecologia, Vol.144(4), pp.534-540
- Academic Unit
- Environment, School of the (CAHNRS)
- Publisher
- Springer-Verlag; Berlin/Heidelberg
- Identifiers
- 99900547310601842
- Language
- English
- Resource Type
- Journal article