Changes in Egg White During Incubation of the Fertile Egg

Fertile, Single Comb White Leghorn hatching eggs were obtained from the K.S.U. poultry farm and incubated at 37.8 ± 0.3° C. and 55–60% relative humidity. Eggs were taken from the incubator daily, candled to insure embryonic development, and quick frozen. The frozen eggs were sectioned and egg white collected carefully to avoid contamination with yolk material, embryonic tissue or blood. Albumen from incubated eggs was examined for changes in pH, free amino acid content, glucose, and sulfhydryl content. Albumen samples were subjected to polyacryamide gel electrophoresis and tested for lysozyme and conalbumin activity. Egg white from incubated eggs increased in free amino acids. Egg white pH at first increased, then decreased with incubation time. No change in sulfhydryl content was observed. Glucose content decreased rapidly after 3 days’ incubation. Electrophoretic analysis indicated severe alterations in egg white proteins during embryogenesis. Assays for lysozyme indicated a complete loss of enzymatic activity by the seventeenth day of incubation. Conalbumin, as determined by chromogenic iron-binding, decreased gradually and was nearly absent after seventeen days.