Improvement by selection means of broiler carcass quality

Abstract

Improvement of broiler carcass quality by usual selection techniques was studied during 8 generations in a synthetic line of fast growing chickens. Foundation stock was obtained by crossing several commercial and experimental lines and was then maintained without selection pressure as a random control line. The so-called "quality" line was obtained from this "control" line to give birds with low abdominal fat percentage, high breast meat yield, and body weight as high as possible. Lowering abdominal fat content was more difficult to obtain than improving breast meat yield because of negative correlations existing between those two characteristics. Nevertheless good results were achieved : in the eighth generation of selection, birds from the selected line were 8% heavier than control, abdominal fat percentage was 21% lower, and pectoral muscles percentage was 11% higher. Higher breast angles were obtained in selected birds, that means a better carcass conformation. Those birds also showed a lower gizzard percentage, and a higher carcass yield with first choice parts (individual pectoral muscles, drumsticks, wings). Relatively homogeneous values were observed for correlations between carcass parts and yields of the two lines in the eighth generation. This result may be due to the fact that general anatomical structure of the birds was not modified in an appreciable way by the type of selection applied in this experiment.