Evaluation of bioelectrical impedance for estimation of body composition in 8-week-old broilers

Bioelectrical measurements (resistance and reactance) were obtained from 35 male and 45 female 8-wk-old broilers using a tetrapolar technique. Body weight, dorsal body length (BL), thigh diameter (TD), and proximate analysis (percentage fat, protein, and moisture) were also ascertained. Twenty birds of each sex were randomly assigned to a calibration group and the remaining birds to a prediction group. Data for birds in the calibration group were used to generate regression equations for estimating whole body composition. Data from birds in the prediction group were collected for possible validation of the calibration equations. Repeatability values for resistance (Re), reactance (Xc), and composition variables were equal to or greater than .78. Coefficients of determination (R2) among percentage body moisture, fat, and protein and body and bioelectrical measurements in males were .41, .36, and .24 (P less than .05), respectively. Percentage moisture in females was predicted by TD2/BL (R2 = .22, P less than .05). Body composition was not adequately predicted by variables measured in this study.