CARCASS CHARACTERISTICS OF CHICKENS FROM EXPERIMENTAL LINES DIVERGENTLY SELECTED ON GROWTH-RATE

Carcass characteristics of chickens from experimental lines divergently selected on growth rate. Cockerels from 2 lines of chickens divergently selected on growth rate were reared together in the same environment, in particular with the same food programme. They were slaughtered at 12 wk old at a mean starved body weight of 677 g (low line, LL) and 1841 g (high line, HL) respectively. Because of heterogeneous variances due to wide differences in live body weights, the non-parametric test of Colin White was used for line comparisons. HL birds showed a higher breast angle than LL birds (60.3 vs 56.0), higher fatness scores (percentages of abdominal and subcutaneous fat), a better carcass yield (60.8 vs 55.8), and higher pectoral muscle (11.4 vs 10.7) and thigh (24.6 vs 21.9) body weight percentages. However, viscera and edible giblets (neck, gizzard, liver, heart) percentages were lower in HL than in LL birds. The results demonstrate allometric relationships between body parts and whole live weight: positive for muscles and fat, negative for viscera and giblets.