Fate of fluorescent stained sperm following insemination: new light on oviducal sperm transport and storage in the turkey

A novel approach was used to evaluate the distribution of sperm in the oviduct of turkey hens inseminated before or after the onset of egg production. Prior to insemination, sperm were stained with the nuclear fluorescent stain bisbenzimide. Sperm distribution in the sperm storage tubules (SST) of the uterovaginal junction and the infundibular tubular glands was determined by use of simultaneous differential interference contrast and fluorescence microscopy. In hens inseminated and examined prior to the onset of egg production, 94% of the SST contained sperm (21% were filled). In contrast, in hens inseminated initially before the onset of egg production and examined after the onset of lay, only 73% of the SST contained sperm (5% were filled); and in hens inseminated initially after the onset of lay and then examined, 78% of the SST contained sperm (4% were filled). Sperm were sparsely distributed in the infundibular tubular glands. Therefore, lower percentages of filled SST were associated with the onset of egg production, an indication that the sperm storage capacity of the SST is diminished with the onset and continuation of egg production. Physical events associated with the daily ovulatory cycle, such as rotation of the egg mass during shell formation, may both displace sperm residing in the SST and diminish the efficacy of sperm entry into the SST.