Stable carbon isotopic evidence for differences in the dietary origin of bone cholesterol, collagen and apatite: Implications for their use in palaeodietary reconstruction

摘要

Rats were raised on a variety of isotopically controlled diets comprising 20% C-3, C-4 or marine protein and C-3 and/or C-4 non-protein or energy (i.e. sucrose, starch and oil) macronutrients. Compound specific stable carbon isotope (813 Q analysis was performed on the cholesterol isolated from the diet (n = 7) and bone (n = 15) of these animals and the values compared with bulk delta(13)C measurements of bone collagen and apatite. The dietary signals reflected by these three bone biochemical components were investigated using linear regression analysis. delta(13)C values of bone cholesterol were shown to reflect whole diet delta(13)C values, collagen to reflect mainly dietary protein values and apatite to reflect whole diet values. Further correlations between dietary protein-to-energy spacings (Delta(13)C(prot-engy) = delta(13)C(protein) - delta(13)C(energy)) and whole diet-to-bone component fractionations (Delta(13)C(bcomp-wdiet) = delta(13)C(bone component) - delta(13) C-(whole diet)) indicates that for hypothetical diets where protein delta(13)C values are equal to energy values, fractionations between whole diet and bone biochemical fractions are -3.3parts per thousand for cholesterol, +5.4parts per thousand for collagen and +9.5parts per thousand for apatite. Moreover, the narrow range of variation observed in apatite-to-cholesterol spacings (Delta(13)C(apat-bchol)) suggests that cholesterol delta(13)C values can potentially also be used as an independent test for the isotopic integrity of apatite delta(13)C values. These insights into bone cholesterol, collagen and apatite dietary signals, diet-to-bone fractionations and bone component-to-bone component spacings provide the basis for more accurate interpretations of the dietary behaviour of archaeological populations and food webs when the delta(13)C analysis of bone is employed. Copyright (C) 2004 Elsevier Ltd. [References: 49]