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United States Department of Agriculture

Agricultural Research Service

Research Project: FUNCTIONAL GENOMICS OF ENHANCED EMBRYO, FETAL, AND NEONATAL DEVELOPMENT AND SURVIVAL IN SWINE Title: Validation of a new body composition method for infant and children using piglets

Authors
item Andres, Aline -
item Mitchell, Alva
item Badger, Thomas -

Submitted to: International Journal of Obesity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 12, 2010
Publication Date: April 1, 2010
Citation: Andres, A., Mitchell, A.D., Badger, T.M. 2010. Validation of a new body composition method for infant and children using piglets. International Journal of Obesity. 34(4):775-780.

Interpretive Summary: The purpose of this study was to investigate the accuracy and precision of the novel quantitative nuclear magnetic resonance (QMR) technology for measuring body composition of infants and children (up to 50 kg), using the pig as model. This technology creates contrast between soft tissues by taking advantage of the differences in relaxation times of the hydrogen nuclei spins in these tissues, leading to a precise and accurate measure of body fat, fat free mass and total water. A total of 50 pigs weighing between 3.0 and 49.1 kg were studied. Each piglet’s body composition was assessed via Dual Energy X-ray Absorptiometry (DXA), Quantitative Nuclear Magnetic Resonance (QMR) and whole body chemical carcass analysis. The precision of the QMR to estimate fat mass (FM), fat free mass (FFM) and total body water (TBW) was excellent. QMR measures of fat mass were highly and significantly correlated with chemical carcass analyses and DXA measures. Compared with the carcass lipid analyses, DXA overestimated FM by 15% on average; whereas, QMR overestimated FM by 2% on average. DXA and QMR FFM results were highly correlated. Total body water measures were highly correlated between the QMR and carcass analyses. In conclusion, QMR provide precise and accurate measures of FM, FFM and TBW in piglets weighing up to 50kg. This new technology is very promising and will allow longitudinal acquisition of data sets in the pediatric population which has been, up to now, a major challenge.

Technical Abstract: The current study was undertaken to validate the first quantitative nuclear magnetic resonance instrument designed and built to assess body composition from birth through adulthood (up to 50 kg). A total of 50 pigs weighing between 3.0 and 49.1 kg were studied. Each piglet’s body composition was assessed via Dual Energy X-ray Absorptiometry (DXA, Hologic QDR 4500), Quantitative Nuclear Magnetic Resonance (QMR, EchoMRI-AH small) and whole body chemical carcass analysis. DXA and QMR were repeated 5 times with repositioning to assess precision. Twenty-five piglets (3.1 to 47.2 kg) were randomly selected to calibrate the QMR instrument. The remainder 25 piglets (3.0 to 49.1 kg) were used to validate the instrument. The precision (coefficients of variation) of the QMR to estimate fat mass (FM), fat free mass (FFM) and total body water (TBW) for 5 consecutive scans was excellent (1.3%, 0.9% and 0.9%, respectively). QMR measures of FM were highly and significantly correlated with chemical carcass analyses and DXA measures (r2=0.99 and r2=0.97, respectively). Compared with the carcass lipid analyses, DXA overestimated FM by 15% on average (~400 g); whereas, QMR overestimated FM by 2% on average (43 g). DXA and QMR FFM results were highly correlated (R2=0.99, P<0.01). Total body water measures were highly correlated between the QMR and carcass analyses (R2=0.99, P<0.01). In conclusion, QMR provide precise and accurate measures of FM, FFM and TBW in piglets weighing up to 50kg. This new technology is very promising and will allow longitudinal acquisition of data sets in the pediatric population which has been, up to now, a major challenge.

Last Modified: 8/1/2014
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