Divergent selection for shape of growth curve in Japanese quail. 4. Carcass composition and thyroid hormones

Ludmila Hyankova (1) , Bozena Novotna (2) , Veerle Darras (3)

1 Genetics and Biometrics
2 Lab Genet Ecotoxicol
3 Laboratory of Comparative Endocrinology

1. Changes in the relative weights of carcass, abdominal fat, breast and leg muscles, and plasma thyroid hormone concentrations occurring during the first six weeks of postnatal growth were analysed in males of HG and LG lines divergently selected for high and low relative body weight (BW) gain between 11 and 28 d of age, respectively, and constant adult BW. 2. The 2nd week of postnatal life was a critical age at which the HG males exhibited a relatively faster growth in comparison with their LG counterparts and permanently exceeded LG males in the percentage of carcass, breast and leg muscle weights. A higher production of muscle tissues was associated with lower accumulation of abdominal fat before sexual maturity. 3. In general, the plasma T3 level of HG quail exceeded that of LG quail. Nevertheless, significant differences were found only at 14, 21 and 28 d of age, i.e. in the period during which the highest inter-line differences in relative growth rate were noted. Also the T3/T4 ratio followed a similar trend while plasma T4 level showed no clear and consistent inter-line differences. 4. The results suggested that the selection for the shape of the growth curve like the selection for body fat modifies the carcass quality owing to shortening/prolongation of acceleration growth phase. Individuals with a short acceleration phase of the growth curve are characterized by low carcass quality during fattening period.

Mots clés: Life Sciences

Ludmila Hyankova, Bozena Novotna, Veerle Darras. Divergent selection for shape of growth curve in Japanese quail. 4. Carcass composition and thyroid hormones. British Poultry Science, 2009, 49 (02), pp.96-102. ⟨10.1080/00071660801949913⟩. ⟨hal-00545326⟩