Effects of selection, over three and four generations, on meat yield and fatness in Muscovy ducks

1. Two experiments were undertaken to analyse the effects of selection for lowering carcase fatness and improving meat yield of Muscovy ducks. The control generation N and the selected generations N + 3 and N + 4 of the same heavy line (Grimaud) were reared under similar conditions. 2. We compared growth, carcase characteristics, chemical composition of breasts and plasma concentrations of very low density lipoproteins (VLDL), triglycerides and phospholipids. 3. Selection induced an increase of body weight (+8% to 10% at slaughter age), a decrease of abdominal fat percentage (-10%) and an improvement of breast and thigh plus shank yields (+3% to 7% and +4% respectively). 4. The lipid content of breast meat decreased in the selected ducks (-14% to -20%), particularly phospholipids and triglycerides. Breasts appeared paler and less red which suggested modifications of muscular fibre composition. 5. We found no significant correlations between plasma VLDL, triglyceride and phospholipid concentrations and carcase fatness. It therefore seems difficult to use these variables as selection criteria for lowering carcase fatness of Muscovy ducklings.