Developmental transition of pectoralis muscle from atrophy in late-term duck embryos to hypertrophy in neonates.

Unlike the mammalian fetus, whose growth is supported by the sustained provision of maternal nutrients, poultry embryos undergo development in a relatively closed space, and the yolk sac serves as the sole nutrient supply for embryonic development throughout the whole incubation period. To increase our understanding of the muscle developmental patterns in the final stage of incubation and early days posthatching, we used late-term duck embryos and newly hatched ducklings as animal models. Pectoralis muscle samples were collected at 22 days (22E) of incubation, 25 days (25E) of incubation, hatching and day 7 posthatching.

Effects of in ovo injecting disaccharides and alanyl-glutamine dipeptide on the energy status in duck embryos and neonates.

This experiment tested the hypothesis that administering additional available nutrients to duck embryos would enhance the glucose store and improve the body growth of ducks. A total of 520 duck eggs of 21 days' incubation containing viable embryos were used in the present study and randomly divided into four treatments. At 23 days of incubation (23E), three groups of eggs were injected with the following solution: (1) sucrose and maltose (DS); (2) l-alanyl-l-glutamine (Ala-Gln); (3) sucrose, maltose and Ala-Gln (DS+Ala-Gln); the remaining groups served as non-injected control.