This work was designed to study the response of Muscovy ducks to different
levels of dietary energy and yeast culture (YC) on performance, carcass yield, carcass
composition and economical efficiency. One hundred and fifty one-day old Muscovy ducklings were wing banded and
were divided into five treatment groups in three replicates of 10 each fed on (2930 &
2730 Kcal ME/Kg) and (3030 & 2475 K cal ME/Kg) energy diets during starting and
growing periods, respectively. YC was added with either high or low energy level. The
calorie: protein ratio was kept constant within each energy level, and each
experimental diet was fed to one of the five treatment groups from one day to 12
weeks old. Live body weight (LBW) and weight gain (WG) of ducks were improved
significantly by feeding high energy diets during starter and grower periods and
declined by feeding low energy grower (LEG) diet. However, feed intake (FI)
increased by feeding LEG-diet, while feed conversion (FC) was better by feeding high .
energy grower (HEG) diet. Dressed weight, edible parts and abdominal fat pad
percentages of birds increased when offered HEG-diet, while YC added levels
showed better values of most growth performance traits by feeding LEG-diet than
when HEG-diet was fed and had no adverse effect on carcass yield. However,
carcass moisture and protein percent decreased while carcass fat content increased
by feeding high energy diets. Economical efficiency (EE) was better for ducks fed
HES-LEG-diets which recommended to be used than the other dietary groups.