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. DS and Ala-Gln injection significantly increased the plasma glucose concentration at hatch and 3 days post-hatch (P < 0.05). Compared with control, the liver glycogen content in the DS group was elevated by 56% at 25 days’ incubation (25E) and by 45% at hatch, respectively (P < 0.05). At 25E, the pectoral glycogen content was increased by 109% in the Ala-Gln group and by 67% in the DS + Ala-Gln group, respectively, when compared with non-injected control. There was high and positive correlation between the body weight (BW) and liver glycogen content (r = 0.809, P < 0.01). The data of the present study suggest that the energy store is probably an important factor in affecting the growth of late-term embryos and ducklings.