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Title: Influence of diet on the distribution of carbon isotopes in animals

Journal Article · · Geochim. Cosmochim. Acta; (United States)

The influence of diet on the distribution of carbon isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant carbon isotopic composition. The isotopic composition of the whole body of an animal reflects the isotopic composition of its diet, but the animal is on average enriched in delta/sup 13/C by about 1/sup 0///sub 00/ relative to the diet. In three of the four cases examined, the /sup 13/C enrichment of the whole body relative to the diet is balanced by a /sup 13/C depletion of the respired CO/sub 2/. The isotopic relationships between the whole bodies of animals and their diets are similar for different species raised on the same diet and for the same species raised on different diets. However, the delta /sup 13/C values of whole bodies of individuals of a species raised on the same diet may differ by up to 2/sup 0///sub 00/. The relationship between the /sup 13/C//sup 12/C ratio of a tissue and the /sup 13/C//sup 12/C ratio of the diet depends both on the type of tissue and on the nature of the diet. Many of the isotopic relationships among the major biochemical fractions, namely the lipid, carbohydrate, and protein fractions, are qualitatively preserved as diet carbon is incorporated into the animal. However, the difference between the delta/sup 13/C values of a biochemical fraction in an animal and in its diet may be as large as 3/sup 0///sub 00/. The delta /sup 13/C values of the biochemical components collagen, chitin, and the insoluble organic fraction of shells, all of which are often preserved in fossil material, are related to the isotopic composition of the diet. These results indicate that it will be possible to perform dietary analysis based on the determination of the /sup 13/C//sup 12/C ratio of animal carbon. Analysis of the total animal carbon will in most cases provide a better measure of diet than the analysis of individual tissues, biochemical fractions, or biochemical components.

Research Organization:
California Inst. of Tech., Pasadena
OSTI ID:
6756796
Journal Information:
Geochim. Cosmochim. Acta; (United States), Vol. 42:5
Country of Publication:
United States
Language:
English

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