Changes of histamine concentration in chicken oviduct during the egg-laying cycle

This study was undertaken to determine histamine concentration in chicken oviductal parts (infundibulum, magnum, isthmus and shell gland) in relation to the egg location within the oviduct and ovulation. The experiment was performed on Hisex Brown laying hens with regular sequences of at least four eggs. Ovulation occurred within 5-15 min of oviposition of the previous egg in the series. Histamine was determined spectrofluorometrically in the following stages of the egg-laying cycle: during c2 oviposition; 0.5 h, 6.5 h, 12.5 h and 18.5 h after c2 oviposition; and during c3 oviposition. Irrespective of the egg formation stage histamine concentration in the examined oviductal parts was arranged in the following order: infundibulum > magnum > isthmus > shell gland. During the egg-laying cycle histamine concentration significantly changed. During oviposition, i.e. just before ovulation of the next egg in the series, histamine concentration significantly increased in the infundibulum while 6.5 h after oviposition, i.e. about 1.5 h of the egg stay in the shell gland, there was a significant increase in histamine concentration both in the infundibulum and the shell gland. In the magnum histamine concentration was elevated when the ovum entered the segment, i.e. 0.5 h after oviposition. There were no changes in histamine concentration in the isthmus. It is suggested that histamine participates in the local events taking place in the hen oviduct during the egg formation cycle.