The usefulness of a new TOBEC instrument (ACAN) for investigating body composition in small mammals

Estimates of water mass, lean body mass (LBM) and fat content based on total body electrical conductivity (TOBEC) measured with ACAN-2 were compared with direct measurements of carcass composition in two species of rodents: the laboratory mouse (n=20) and the bank vole (n=14). There was a strong linear relation relation between ACAN readings and lean mass or water mass. Body temperature did not affected the results, but the readings were dependent on the species and sex of the individuals. That could be due to differences in the body shape. The accuracy of predicting an average LBM or water mass was very high (1.5%), but the errors for predicting individual values were larger (8.5%). The predicted fat content values have identical confidence intervals as that for LBM. However, the relative error for prediction of the amount of fat was higher, becouse the mass of fat was much smaller than LBM.