The fate of spermatozoa that do not participate in fertilization was investigated by electron microscopy. After artificial insemination, we observed several spermatozoa between the fibers of the outer layer of the vitelline membrane of the ovum. One or more spermatozoa were also found in a phagocytic vesicle of macrophages located in the intercellular space of the mucosal epithelium of the infundibulum or in the outer layer of the vitelline membrane.
From these observations, we assume that the superfluous spermatozoa in the lumen of the anterior part of the oviduct might be removed by inclusion into the outer layer of the vitelline membrane and by phagocytosis by macrophages.
Key words Spermatozoa - Vitelline membrane - Macrophage - Fowl - Electron microscopy
The authors are greatly indebted to Assoc. Prof. Osamu Koga for his invaluable advice. The authors also wish to thank Mr. Takayuki M
ri for his helpful suggestions and technical advice. This investigation was supported by a grant from the Ministry of Education of Japan (156185)