Table of Contents
ISRN Zoology
Volume 2012, Article ID 673050, 9 pages
http://dx.doi.org/10.5402/2012/673050
Research Article

Organ-Tissue Level Model of Resting Energy Expenditure Across Mammals: New Insights into Kleiber's Law

1Obesity Research Center, St. Luke’s-Roosevelt Hospital, College of Physicians and Surgeons, Columbia University, New York City, NY 10025, USA
2Department of Statistics, Columbia University, New York City, NY 10027, USA
3Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA

Received 25 April 2012; Accepted 5 August 2012

Academic Editors: A. Arslan, K. E. Ruckstuhl, and E. Tkadlec

Copyright © 2012 ZiMian Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Kleiber’s law describes the quantitative association between whole-body resting energy expenditure (REE, in kcal/d) and body mass (M, in kg) across mature mammals as REE . The basis of this empirical function is uncertain. Objectives. The study objective was to establish an organ-tissue level REE model across mammals and to explore the body composition and physiologic basis of Kleiber’s law. Design. We evaluated the hypothesis that REE in mature mammals can be predicted by a combination of two variables: the mass of individual organs/tissues and their corresponding specific resting metabolic rates. Data on the mass of organs with high metabolic rate (i.e., liver, brain, heart, and kidneys) for 111 species ranging in body mass from 0.0075 (shrew) to 6650 kg (elephant) were obtained from a literature review. Results. predicted by the organ-tissue level model was correlated with body mass (correlation ) and resulted in the function , with a coefficient and scaling exponent, respectively, close to 70.0 and 0.75 () as observed by Kleiber. There were no differences between and calculated by Kleiber’s law; was correlated () with . The mass-specific , that is, , was correlated with body mass () with a scaling exponent −0.246, close to −0.25 as observed with Kleiber’s law. Conclusion. Our findings provide new insights into the organ/tissue energetic components of Kleiber’s law. The observed large rise in REE and lowering of REE/M from shrew to elephant can be explained by corresponding changes in organ/tissue mass and associated specific metabolic rate.