EFFECT OF STARVATION BEFORE SLAUGHTER AND SIZE BEFORE FORCE-FEEDING ON FATTY LIVER COMPOSITION IN MUSCOVY DUCKS

The biochemical composition of the liver and total fatty acid profile were recorded in 42 fatty livers of male Muscovy ducks after 12 1/2 d of force feeding. The effects of starvation (J1 : 13 h and J2 : 19 h) and body size (Fle, light: 3,66 kg; FMo, middle : 3.79 kg and Flo, heavy: 3.92 kg) before force-feeding were studied. A longer starvation period before slaughter induced losses resulting from the emptying of the digestive tract (330 vs 291 g) for the FMo and FLo birds in particular. Fatty liver weights decreased by almost-equal-to 15%, but no difference was noticed in their biochemical composition and fatty acid profile. The undefined amount decreased in the same manner in the 3 groups when the starvation period was increased (23.71 vs 15.77 g). Technical melting estimated by liver weight losses after 55-degrees-C and 105-degrees-C heat treatment was significantly greater after 19 h starvation (8.68 vs 19.64% and 44.56 vs 54.04%, respectively). This may be the result of increased lipolysis. Differences in body size between the 3 groups remained after force feeding. The livers of FLe ducklings were similar as regards weight and lipid percentage, but they exhibited a greater proportion of moisture or proteins, and correlatively a similar undefined amount. These birds presented significantly more C16:0 (34.7 vs 32.1%) and less C18:0 (9.8 vs 11.9%), C18:2 (0.9 vs 1.4%) than the heavier group. This difference might reflect a lower saturation point for the lightest animals.