Relationships between total body electrical conductivity (TOBEC) and carcass composition of male broilers

Two experiments with male broilers were performed to examine the relationsh ips between total body electrical conductivity (TOBEC) and carcass composit ion. The TOBEC-measurement principle relies on higher conductivity of body fat free mass compared to body fat mass due to the fact that both compartme nts differ markedly in their contents of free movable ions. Experiments wer e designed to induce large differences in body fat contents by increasing d ietary protein concentrations (20 % and 30 % in experiment 1, which lasted from day 1 to 25 of age; 20 %, 25 % and 30 % in experiment 2 which lasted f rom day 1 to 35 of age). As expected, an increase in dietary protein concen tration resulted in heavier broilers and reduced feed to gain ratio, in lea ner carcasses and lower fatness as indicated by higher dressing and breast meat percentages and lower body proportions of abdominal plus visceral fat and breast skin, respectively. TOBEC-values were positively correlated to l ive weight (LW, kg) and breast meat yield (BM, % of live weight) whereas ne gative relationships were detected to abdominal plus visceral fat (AF, % of live weight). The following multiple linear regression equations were esti mated: Experiment 1. TOBEC-value = -982 + 28.2 *BM + 1630 *LW (r(2) = 0.834, n = 1 26) TOBEC-value = -572 - 85.5 SAF + 1747 *LW (r(2) = 0.849, n = 126) Experiment 2, TOBEC-value = -655 + 13.8 *BM + 581 *LW (r(2) = 0.527, n = 96 ) TOBEC-value = -52 - 51.6 *AF + 433 *LW (r(2) = 0.621, n = 96) It was concluded that it should be possible to predict the proportions of b reast meat yield or abdominal plus visceral fat of broilers with knowledge of live weight and TOBEC-values. However, the moderate proportion of varian ce accounted for the chosen model has to be considered.