A physiological study of egg shell formation in the domestic fowl

• Published in: The Japanese Journal of Veterinary Research Vol. 45; no. 4; p. 224
• Main Author: Tadashi Nakada
• Format: Journal Article
• Language: English; Japanese
• Published: Graduate School of Veterinary Medicine Hokkaido University 27-02-1998
• ISSN: 0047-1917

There is some evidence that the effective stimulus for secretion of any part of the oviduct is mechanical. Pearl and Surface1) showed that when the intestine was anastomosed to the above the uterus the feces extruded through the vagina or retained in the uterus were covered with a deposit of shell material. They concluded that the immediate effective stimulus to shell secretion was mechanical and that shell formation was a local reflex not depend upon a specific activity of other parts of the reproductive apparatus. However, Nakada et al.2), reported that shell formation did not always follow the introduction of agar-agar into the oviduct. The other possible factors responsible for the shell formation have not been fully understood. To investigate this, the artificial yolk(A.Y.)which was made of 3% agar was inserted into the empty oviduct at various times before and after ovulation. The results obtained were as follows:When the A.Y. was inserted near the expected time of ovulation, the normal set of egg envelopes including the chalazae, albumen, shell membrane and shell was formed around the A.Y., and most of eggs containing A.Y. were laid as hard-shelled eggs.