Role of the Shell Gland in Determination of Albumen Quality

Experiments were conducted to determine the crude ovomucin contents of eggs at various stages of egg formation. The total ovomucin content was greatest in eggs obtained from the isthmus four and one-half hours after oviposition of the previous egg. It was unchanged at six hours, after the egg had entered the shell gland, but declined precipitously during the first few hours in the shell gland, remaining relatively constant thereafter until oviposition. The rapid decline in ovomucin content of eggs in shell gland corresponded to the period of rapid egg white plumping. Fresh eggs which differed in albumen quality also differed in crude ovomucin content. Hens which were selected for differences in albumen quality of fresh eggs did not differ in the total ovomucin content of eggs obtained from the isthmus. However, the differences in ovomucin content associated with egg quality were apparent in eggs obtained from the shell gland within eight hours after oviposition of the previous egg. Hens fed a diet supplemented with 2% ammonium chloride in an attempt to increase albumen quality also did not differ in ovomucin content of isthmal eggs. Ovomucin was markedly increased in eggs of this group after oviposition; however, variations in ovomucin content among hens selected for differences in egg quality were not due to differences in the dilution of egg white by plumping fluid in the shell gland. High and low quality groups contained comparable amounts of albumen in eggs at all stages of formation. Thus, variations in albumen quality among hens within a strain become differentiated during the first few hours in the shell gland and are probably related to chemical interactions between plumping fluid and preformed albumen.