Effect of sex on growth, technological and organoleptic characteristics of the Muscovy duck breast muscle.

1. The aim of our study was to analyse the consequences of sexual dimorphism on muscular growth and on technological and organoleptic characteristics of breast muscle. Ten males and 10 females of the R51 line (Grimaud) were weighed every fortnight, from 1-d-old to 15 weeks of age, and then slaughtered. Four muscles, Sartorius (SART), Anterior and Posterior latissimus dorsi (ALD, PLD), Pectoralis major (PM) were removed and weighed. The activities of 3 enzymes (citrate synthase, beta-hydroxyacyl CoA dehydrogenase, lactate dehydrogenase) which indicate muscular metabolic activity were assayed. pH value, colour and juice loss of breast muscle were measured on ducks slaughtered between 8 and 15 weeks of age. Sensory analysis, (tastes) was also carried out. 2. At 15 weeks of age, males weighed 4573 g and females 2879 g. Muscle weight and muscular glycolytic activity increased regularly with age. Females showed earlier muscular growth. Sexual dimorphism had a significant effect on muscular growth from 6 weeks of age for ALD, 8 weeks of age for PLD and SART and 10 weeks of age for PM. 3. With age, breasts became redder and darker. The post-mortem fall of pH and juice loss after 24 h of storage at 4 degrees C increased. Females displayed more precocious muscular maturity. The changes in organoleptic characteristics showed a decrease in tenderness, juiciness and mellowness and an increase in flavour and stringiness with age. At any given age, female breast muscles appeared less tender, less juicy and less mellow but had a more intense flavour and seemed more stringy than those of males.