TY - JOUR
T1 - Simple, rapid, and non-invasive measurement of fat, lean, and total water masses of live birds using quantitative magnetic resonance
AU - Guglielmo, Christopher G.
AU - McGuire, Liam P.
AU - Gerson, Alexander R.
AU - Seewagen, Chad L.
N1 - Funding Information:
Acknowledgments We are grateful to Echo Medical Systems and Glendale RV for working with us to customize and troubleshoot a QMR system and an RV trailer. In particular, we thank G. Taicher, B. Burdette, G. Fischel, I. Kovner, V. Rubin and G. Marra for their efforts. We thank E. Price and S. MacDougall-Shackleton for helping us to obtain birds, D. Cerasale for measuring bird skeletons, Y. Morbey for programming simulations in SAS, and H. Mouritsen for insight into the potential effects of magnetic fields. Thanks to S. Nebel for German translation. Funding was provided by an NSERC Discovery Grant to C.G.G., grants from the Leaders Opportunity Fund of the Canada Foundation for Innovation and the Ontario Research Fund to C.G.G. and E. MacDougall-Shackleton, and in-kind contributions from Echo Medical Systems and Glendale RV.
PY - 2011
Y1 - 2011
N2 - An ideal technology for non-invasive analysis of body composition should provide highly precise and accurate direct measurements of fat, lean mass and total water of non-anaesthetized subjects within minutes. We validate a quantitative magnetic resonance (QMR) body composition analyzer for birds using House Sparrows (Passer domesticus), European Starlings (Sturnus vulgaris), and Zebra Finches (Taeniopygia guttata). Subjects were scanned awake for three replicate scans of 1.5-3.5 min, and results were compared to gravimetric chemical analysis. Coefficients of variation were ≤3% for dry fat, wet lean mass and total water. Accuracy of the raw QMR data for fat and total water were high (relative errors ≤±12.5 and ≤±4%, respectively), but wet lean mass was significantly biased because QMR does not detect structural tissues. Calibration against gravimetric chemical analysis removed bias and improved accuracy; relative errors were ±6-11% for fat, ±1-2% for wet lean mass, and ±2-4% for total water. QMR is field-portable when transported in a temperature-controlled trailer, and can be used to study fuel storage and body composition dynamics during migration, reproduction, nestling growth, or wintering. In the laboratory, QMR can be used for longitudinal studies of birds under photoperiod, endocrine or other manipulations. Measurements taken before and after metabolic challenges, such as flight in a wind tunnel, make it possible to calculate energy costs, fuel selection and changes in hydration. QMR should find wide application in field and laboratory studies.
AB - An ideal technology for non-invasive analysis of body composition should provide highly precise and accurate direct measurements of fat, lean mass and total water of non-anaesthetized subjects within minutes. We validate a quantitative magnetic resonance (QMR) body composition analyzer for birds using House Sparrows (Passer domesticus), European Starlings (Sturnus vulgaris), and Zebra Finches (Taeniopygia guttata). Subjects were scanned awake for three replicate scans of 1.5-3.5 min, and results were compared to gravimetric chemical analysis. Coefficients of variation were ≤3% for dry fat, wet lean mass and total water. Accuracy of the raw QMR data for fat and total water were high (relative errors ≤±12.5 and ≤±4%, respectively), but wet lean mass was significantly biased because QMR does not detect structural tissues. Calibration against gravimetric chemical analysis removed bias and improved accuracy; relative errors were ±6-11% for fat, ±1-2% for wet lean mass, and ±2-4% for total water. QMR is field-portable when transported in a temperature-controlled trailer, and can be used to study fuel storage and body composition dynamics during migration, reproduction, nestling growth, or wintering. In the laboratory, QMR can be used for longitudinal studies of birds under photoperiod, endocrine or other manipulations. Measurements taken before and after metabolic challenges, such as flight in a wind tunnel, make it possible to calculate energy costs, fuel selection and changes in hydration. QMR should find wide application in field and laboratory studies.
KW - Body composition
KW - Condition
KW - Energetics
KW - Lipid
KW - Magnetic resonance
KW - Validation
UR - http://www.scopus.com/inward/record.url?scp=80052626713&partnerID=8YFLogxK
U2 - 10.1007/s10336-011-0724-z
DO - 10.1007/s10336-011-0724-z
M3 - Article
AN - SCOPUS:80052626713
SN - 2193-7192
VL - 152
SP - S75-S85
JO - Journal of Ornithology
JF - Journal of Ornithology
IS - 1 SUPPL
ER -