Relative Size of the Hind Limb and Wing Part, and the Muscle Distribution in Chicks and Broilers Produced Under Different Nutritional Regimes

Abstract

1. The purpose of the present study was to develop a feeding method for producing an increased size of the hind limb part of chickens, of a darker colour, using different nutritional regimes. In experiment 1, chicks were reared with 4 feeds of different nutritional levels up to post-hatching 21 days. 2. Carcass weight differed by 2.4 times between the largest and the smallest group effects. In the smallest chicks the percentages of the hind limb relative to the wing for both the total weight and muscle weight were 93%, much larger than the 82-86% and 77-83%, respectively, in the other chick groups. A greater depression of the wing development was observed in the smallest chicks. 3. In experiment 2, broilers were reared under different nutritional regimes during the early period of 0 to 21 days of age, and then the later period of 22 to 80 days of age. The largest carcass weight was observed in the conventionally fed broilers, followed by the broilers with a compensatory growth in the later period, and the smallest weight was shown by the broilers with the growth limitation in the later period. 4. The smallest broilers exhibited larger values (88-90% for the total weight, 84-86% for the muscle weight) in the percentages of the hind limb relative to the wing compared with the other bird groups (80-81% for the total weight, 74-78% for the muscle weight). 5. In experiment 3, the broilers of the smallest carcass weight were fattened for a further 15 days to attain enough body size. By 95 days of age, the percentage of the hind limb relative to the wing was maintained at 89-90% for the total weight and 86% for the muscle weight. 6. These results suggest that the percentage of the hind limb relative to the wing could be increased by restricting broiler growth during the later growth stages, while the large relative weight of the hind limb resulting from severe disturbance of early growth had completely disappeared after a compensatory growth during the later stages.