one male duck per replicate was randomly selected and weighed after feed deprivation for 12 h. Blood Samples (about 5 mL each) were taken from wing vein and centrifuged at 3000 × g for 15 min at 4◦C to separate serum, which was frozen at −20◦C for further analysis. After blood collection, ducks were killed by cervical dislocation. Pectoralis major muscle samples were immediately taken and stored at 4◦C for meat quality analysis. Abdominal fat yield was calculated as the percentage of eviscerated weight. Subcutaneous fat thickness and intramuscular fat width were measured by a vernier caliper as previously described