The difference in the ability of Pekin and Muscovy ducks to develop hepatic steatosis could result from a different peripheral lipoprotein lipase (LPL) activity, which hydrolyses triacylglycerol secreted by the liver. We studied the kinetics of plasma LPL activity in response to a meal at different ages in Pekin and Muscovy ducks. For that purpose, blood samples were taken at 5, 9, 12, 13, and 14 wk of age just before and 1, 2, 4, and 8 h after a meal. To release LPL into general circulation, an i.v. injection of heparin (400 IU/kg of BW) was administered 10 min before blood collection. For that reason, different ducks per genotype were used for each point of measurement (n = 6). Plasma LPL activity measured before the meal was negatively correlated with the weight of the fatty liver measured in the same ducks at 14 wk of age (r = -0.58, P < 0.001). Plasma triacylglycerol level measured before the meal was negatively correlated with plasma LPL activity measured in the same ducks (r = -0.31, P = 0.025) and was negatively correlated with plasma LPL activity measured in the same ducks for each age and each timing (r = -0.39, P < 0.001). At 14 wk of age for Muscovy and Pekin ducks, we observed that a high plasma LPL activity (> 200 IU/L of plasma) corresponded to a relatively low development of fatty liver (190 g) induced by overfeeding, whereas a low plasma LPL activity (<150 IU/L of plasma) corresponded to a high propensity to develop fatty liver (470 g). In conclusion, plasma LPL activity measured just before the meal during the rearing period could be used as a marker of hepatic steatosis development during the overfeeding period.