High Fat Diet (HFD) Challenge
HFD challenge is an accepted model for diet-induced obesity. Mice are fed 45% lard diet from weaning. Serial measurements of body composition (fat and lean body mass) are obtained by Quantitative Magnetic Resonance (QMR). HFD challenged mice are also given glucose tolerance and insulin tests.
Body fat is measured non-invasively and non-destructively by nuclear magnetic resonance (NMR) using the Bruker Minispec QMR Analyzer (Bruker Optics; Billerica, MA). The mouse is placed in a sample tube, which is inserted vertically into the Minispec. The entire mouse is exposed to various sequences of magnetic fields for 54 seconds. Signals are generated by the hydrogen nuclei as they spin about their axes. The amplitude, duration, and spatial distribution of these signals are related to the properties of fat and non-fat tissues; the Minispec software (v2.20 Rev.01) calculates the weights of fat and non-fat tissue based on these signals.
Displayed below is a sample graph of how body mass composition observations are presented. In comprehensive phenotypic data packages graphs are interactive. Raw or calculated data and statistics can be seen by clicking on points in the graph.