Seventy-two Pekin ducklings aged 56 days were divided into two ~i (36
males and 36 females). Birds (rom each sex were divided Into two experimental diets
{Force feeding and ad-libtum (commercial diet)} for 21 days. Birds from each
experimental diet were divided into Ihree groups according to their body weight
(heavy, medium and lightl. This work aimed to study the effect of sex. short time of
force feeding and body weight on some productive and metabolic responses of Pekin
ducks. Results obtained showed that: Males were higher in Iheir body weight and improved feed efficiency than
females. Force-feeding significantly increased body weight and weight gain. Heavy
weight dUCKS were superior in their body weight and weight gain. Females significantly had the higher absolute and relative weights of
abdominal (at (33.5 gm and 3.35 % Vs32,1 gm and 3.21 %, respectively). Force-
feeding increased absolute and proportional weights of liver, carcass traits abdominal
fat. Birds of heavy group were superior in absolute weights of liver. carcass traits and
abdominal fat. Females had higher serum total protein. albumin and globulin than males. Force-feeding increased serum total protein3.56 gm/dl), globulin (2.09 gm/dl) and
serum cholesterol (281.0 mg/dl) than feeding ad-lib. (340,1.89 gm/dl and 261.7 mgldl,
respectively). However, ad-lib. feeding significantly increased AJG ratio. Heavy body
weight ducklings had significantly the highest averages of serum total protein.
albumin, globulin and cholesterol Tissues creatinine significantly increased in males (0.781 mg/g) than Females
(0.735 mg/g), while. serum creatinine was significantly higher in females (0.499 mg/dl)
than males (O.314mg/dl). Force-feeding recorded Significantly the higher averages of
serum and tissues creatinine. Birds of heavy group had Significantly the highest
averages of serum uric acid and tissues creatinine. However, serum creatinine
recorded significantly its highest value in medium body weight birds. Females had Significantly higher serum GOT and alkaline phosphatase than
males. Force-feeding increased Significantly serum GOT and GPT transaminases
.Serum GOT and GPT transaminases increased in medium body weight ducklings.
On the other hand, heavy body weight ducklings recorded the highest average of
serum alkaline phosphatase.