Age-related changes in the distribution of lean, fat with skin and bones in duck carcases.

The experimental birds were Pekin ducks (352 males and 352 females) reared to the age of 13 weeks. They were fed standard diets ad libitum. Starting from the second week, 21 males and 21 females were slaughtered every 7 d. Their carcases were divided into the following elements: neck, wings, legs, breast and back, which were then dissected into lean, skin with fat and bones. The body weights of one-day-old ducklings were similar (circa 62 g), but at 5 weeks of age the males were heavier than the females, and at 13 weeks of age their body weights were 3537 g and 2994 g, respectively. In 2-week-old ducks 55.77% of lean was located in the legs, 15.91% in the back part, 2.78% in the wings, 12.47% in the neck and only 13.12% in the breast. Considerable changes in the distribution of lean were noted in the ducks aged 7 weeks. Its percentage decreased in the legs (to 29.34%) and increased in the breast and wings (to 36.86% and 10.96%, respectively). Age-related changes in the distribution of skin with fat were smaller. Its percentage increased in the wings, legs and back, and decreased in the neck and breast. Until the age of 7 weeks the percentage of bones was decreasing quickly in the legs and increasing in the neck and breast, compared with their total weight in the carcase.