A 2-factor test design was used to investigate the effect of an emulsifier (Aldo (R), Lonza, America) (200 g/t) in the diet of Cherry Valley meat ducks to replace some of 2 different oils (animal fat and vegetable oil) on meat production performance, slaughter traits, and fat metabolism. The 900 healthy 18-day-old ducks were grouped into 6 treatments, each with 5 replicates and 30 meat ducks per replicate. The 2 fat sources were established as a positive control group, a negative control group (positive control group-some oil (equivalent to metabolic energy of 50 kcal/ton)), and an emulsifier ...