Energy sensing in developing chicken embryos and posthatch chicks from different size eggs.

Area of Science:

• Animal Physiology
• Developmental Biology
• Nutrient Metabolism

Background:

• 5 -adenosine monophosphate-activated protein kinase (AMPK) is a key energy sensor.
• AMPK's role in nutrient utilization during embryonic development is not fully understood.
• Broiler breeder egg size varies significantly with hen age, impacting nutrient composition.

Purpose of the Study:

• To investigate the role of liver AMPK activity in broiler breeder embryos.
• To determine if egg size influences AMPK activity during embryonic development.
• To explore the relationship between nutrient supply and AMPK-mediated metabolism.

Main Methods:

• Broiler breeder eggs from young (26-wk) and old (42-wk) hens were classified as small or large, respectively.
• Embryonic liver AMPK activity was measured on specific days (e11, e14, e17, e20) and posthatch day 1.
• Egg and embryo weights, as well as yolk-to-albumen ratios, were recorded.

Main Results:

• Large eggs had a higher initial yolk-to-albumen weight ratio compared to small eggs.
• Embryo weight differences emerged from embryonic day 17 onwards.
• Liver AMPK activity was consistently higher in embryos from large eggs across all sampling points, peaking on embryonic day 14.

Conclusions:

• Liver AMPK activity is elevated in broiler embryos developing in larger eggs.
• Increased AMPK activity in large-egg embryos may enhance nutrient metabolism to support rapid growth.
• These findings provide the first evidence linking liver AMPK activity to egg size and nutrient composition in chicken embryos.