Abstract
For healthy development, an avian embryo needs the nutritional and functional molecules maternally deposited in avian eggs. Egg white not only provides nutritional components but also exhibits functional properties, such as defenses against microbial invasion. However, the roles of the more detailed messages in embryo development remain unclear. In this study, a tandem mass tag labeling quantitation approach was used to innovatively identify the differential proteins in the egg whites of fresh eggs produced by hens with divergent high/low hatchability and in the egg whites of embryonated eggs with healthy and dead embryos. A total of 378 proteins were quantified in egg white, which is the most complete proteome identified for egg white to date, and up to 102 differential proteins were identified. GO enrichment, pathway, and hierarchical clustering analysis revealed some of the differential proteins that are the main participants in several biological processes, including blood coagulation, intermediate filament, antibacterial activity, and neurodevelopment. A list of 11 putative protein biomarkers, such as keratin (KRT19, KRT12, KRT15, and KRT6A), which is involved in cell architecture, and fibrinogen (fibrinogen alpha chain, fibrinogen beta chain, and fibrinogen gamma chain), which is related to blood coagulation, were ultimately screened. The current study screened egg white proteins that can predict low hatchability and embryonic death and deciphered the role of these proteins in embryonic development, which is meaningful for the comprehensive understanding of embryonic growth.