Carcase characteristics of a heavy Japanese quail line under introgressionwith the roux gene

1. The roux plumage sex-linked recessive gene may be used for early sexing of Japanese quail in crossbreeding production systems with wild-type and ro ux lines. However, associated effects of the gene on carcase and meat compo sition need to be assessed. 2. Quail carcases from pure Line K males and females (100% K), a heavy meat line which was used as the recipient line for the introgression of the rou x gene, and from same-age roux or wild-type females from the second generat ion of introgression (75% K) were dissected. The effects of sex, line and p lumage colour on carcase components and on protein and lipid contents of va rious tissues were estimated. 3. Expected sex differences in carcase weights were obtained, with marginal ly higher values for females. However, weights of parts and carcase yield ( ratio of empty carcase weight without head, neck and feet over live body we ight) were similar for both sexes in pure Line K which had a 68% carcase yi eld. Lipid contents in leg meat were higher in males (3.1%) than in females (2.7%). 4. The roux gene did not seem to have any major impact on carcase parts or composition. However, in roux birds, leg skin was marginally higher in lipi ds and pectoralis major lower in proteins than in wild-type ones.