Study on differentiation during embryonic development across selective and ancestral breeds

Area of Science:

• Poultry Science
• Developmental Biology
• Muscle Physiology

Background:

• Investigating embryonic muscle development is crucial for understanding post-hatch performance.
• Strain-specific differences in muscle properties can emerge during early development.
• Broiler and native chicken breeds exhibit distinct growth patterns.

Purpose of the Study:

• To explore the effect of genetic strain on muscle properties during embryonic development.
• To investigate muscle regulation in selected and unselected chicken breeds.
• To identify early indicators of diverging growth patterns.

Main Methods:

• Comparison of four chicken strains: JingNing (JN) native, HuangYu (HY) broiler, BaiYu (BY) broiler, and Hyline layer.
• Monitoring embryonic movement and body weight from Hamburger & Hamilton stage (HH)24 to ED18.
• Analyzing muscle fiber diameter and insulin-like growth factor-I (IGF-I) expression via Western blotting.

Main Results:

• Embryonic movement varied between breeds, with broilers showing more activity at specific stages.
• Broiler embryos generally had greater body weight than native and layer breeds.
• Muscle fiber diameter differed, with broilers having smaller fibers initially, then larger than JN chickens.
• IGF-I expression was continuous but showed distinct peaks in broilers (HH19-HH24) and JN chicks (HH27-HH31).

Conclusions:

• Diverging growth patterns among chicken breeds are evident during embryonic stages.
• Differential expression of IGF-I is implicated in embryonic cell proliferation and differentiation, influencing growth trajectories.
• Early embryonic development provides insights into post-hatch muscle property variations.