Skip to main content
ARS Home » Research » Publications at this Location » Publication #147101
Title: EXPRESSION OF THE DIETARY ISOTOPE SIGNAL IN THE COMPOUND-SPECIFIC DELTA 13C VALUES OF PIG BONE LIPIDS AND AMINO ACIDS

Author
item HOWLAND, M. - UNIV OF BRISTOL UK
item CORR, L. - UNIV OF BRISTOL UK
item YOUNG, S. - HARVARD UNIVERSITY
item JONES, V. - UNIV OF BRISTOL UK
item JIM, S. - UNIV OF BRISTOL UK
item VAN DER MERWE, N. - UN OF CAPE TOWN
item Mitchell, Alva
item EVERSHED, R. - UNIV OF BRISTOL UK

Submitted to: International Journal of Osteoarchaeology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2003
Publication Date: 5/1/2003
Citation: Howland, M.R., Corr, L.T., Young, S.M., Jones, V., Jim, S., Van Der Merwe, N.J., Mitchell, A.D., Evershed, R.P. 2003. Expression of the dietary isotope signal in the compound-specific delta 13C values of pig bone lipids and amino acids. International Journal of Osteoarchaeology. 13:54-65.

Interpretive Summary: Naturally occurring differences in the carbon and nitrogen stable isotope content of diets can be used to study how the diets are utilized by the animal. Furthermore, the stable isotope analysis of tissues in the body can be used as a signature that reflects the type of diet that the animal was fed. The purpose of this study was to develop a model using pigs and based on diets of known composition that could be used to extrapolate between tissue analysis and diet composition. Close relationships were found between cholesterol and non-essential fatty acids in the bone and the composition of the whole diet. Similarly, close relationships were observed between the non-essential amino acid components of bone collagen and the whole diet.

Technical Abstract: Pigs were raised on six isotopically controlled diets to examine the dietary macronutrients used in the synthesis of bulk bone biochemical components (apatite, collagen and lipids) and individual compounds (bone fatty acids, cholesterol and amino acids from collagen). 13C values of apatite and bulk bone lipids reflected those of the whole diet, with 13Capatite-wholediet = 10.2 ± 1.3 and 13Cbonelipids-wholediet = -2.4 ± 0.7. A wide variation observed in the 13Ccollagen-wholediet values (0.5 to 6.1) was hypothesized to reflect the relative importance of (i) the direct incorporation of essential amino acids, and (ii) the balance between direct incorporation and de novo synthesis of non-essential amino acids. Linear regression (n = 6) was used to assess the relationship between the 13C values of whole diet and bulk bone components and individual compounds. Whole diet 13C values showed a strong correlation with those of bone cholesterol (R2 = 0.81) and non-essential fatty acids (0.97 R2 0.99). Not surprisingly, bone linoleic acid 13C values correlated well with dietary linoleic acid (R2 = 0.95). Mass balance calculations using the 13C values of single amino acids accurately predicted the 13C value of whole collagen. The 13C values of whole diet were well correlated with those of the non-essential amino acids, alanine (R2 = 0.85) and glutamate (R2 = 0.96) in collagen. The essential amino acids leucine (13Ccollagenleu-dietleu = 0.5 ± 1.2) and phenylalanine (13Ccollagenphe-dietphe = -0.6 ± 0.6) showed little isotopic fractionation between diet and bone collagen.