Incorporation of 14 C-Amino Acids into Egg Proteins by the Laying Hen , ,

LAYING hens have been fed and injected with various radioactive compounds in order to investigate the synthesis of egg constituents as well as to produce labeled egg materials for use in subsequent experimentation. Mandeles and Ducay (1962) injected laying hens with 14 C-lysine and 14 C-glutamic acid and examined the radioactivity in the conalbumin, ovalbumin, and lysozyme protein fractions of the egg white. Following a single injection of the two amino acids, peak activities in the egg white proteins were observed in the second egg produced after injection. The rates at which labeled amino acids were incorporated into the conalbumin and ovalbumin fractions were similar, but higher than for the lysozyme fraction. These observations in conjunction with results obtained with oviduct minces (Mandeles and Ducay, 1962) suggested that the time or rate of synthesis for these proteins varied during the egg laying cycle and that the oviduct was the common site of…