Effect of Embryonic Development on the Chicken Egg Yolk Plasma Proteome after 12 Days of Incubation

To better appreciate the dynamics
of yolk proteins during embryonic
development, we analyzed the protein quantitative changes occurring
in the yolk plasma at the day of lay and after 12 days of incubation,
by comparing unfertilized and fertilized chicken eggs. Of the 127
identified proteins, 69 showed relative abundance differences among
conditions. Alpha-fetoprotein and two uncharacterized proteins (F1NHB8
and F1NMM2) were identified for the first time in the egg. After 12
days of incubation, five proteins (vitronectin, α-fetoprotein,
similar to thrombin, apolipoprotein B, and apovitellenin-1) showed
a major increase in relative abundance, whereas 15 proteins showed
a significant decrease in the yolks of fertilized eggs. In unfertilized/table
eggs, we observed an accumulation of proteins likely to originate
from other egg compartments during incubation. This study provides
basic knowledge on the utilization of egg yolk proteins by the embryo
and gives some insight into how storage can affect egg quality.