Influence of protein and methionine concentrations and body size on the growth and carcase of muscovy ducks in the finishing stage of production

1. The effect of two dietary protein (125 vs 145 g/kg) and methionie (2.2 vs 5.2 g/kg) concentrations on the growth and carcase composition of male Muscovy ducklings was followed for 15 days. In the first experiment, two weight groups (light (Lw) and heavy (Hw)) of 64 birds each were compared while in the second, the comparison concerned hybrids (R61 and R31, 88 ducks each). At the beginning of the experiments, the ducks were 11 and 10 weeks old, respectively.

2. Meal feeding, associated with adequate rationing, reduced fattening but not muscular development. Hybrid R31 growth rate was faster than that of R61. In the two experiments, the birds whose growth had been slower before the beginning of the test period displayed the highest growth rate which was mainly caused by an increase in breast muscle.

3. Methionine supplementation (5.2 g/kg) improved the muscular development of the fillets. Minimal protein requirements were close to 10.3 g CP/MJ ME, but a diet with 12.7 g CP/MJ ME resulted in a slightly higher growth rate in ducklings with delayed growth.