Desialylation of the rooster sperm's glycocalyx decreases sperm sequestration following intravaginal insemination of the hen.

Competitive fertilization was used to study sequestration of neuraminidase-treated sperm within the hen's sperm-storage tubules. The feather color inhibitor gene, I, was used to determine paternity of chicks hatched from eggs laid over a 12-day interval following a single intravaginal insemination. The insemination dose was 1 x 10(8) sperm per hen. The insemination of New Hampshire hens (i/i) with a 50:50 ratio of washed Brown (i/i) and washed White (I/I) Leghorn sperm yielded a 45:55 ratio of brown (i/i) to yellow (I/i) chicks. In contrast, a 14:86 ratio of brown to yellow chicks was obtained when Brown Leghorn sperm were treated with neuraminidase and then washed free of the enzyme before admixture with nontreated washed White Leghorn sperm. The effective insemination dose was reduced, as 18% fewer chicks were sired when Brown Leghorn sperm were pretreated with neuraminidase. When percentages of brown chicks were plotted as a function of time, both plots conformed to a straight line. Neither slope differed from zero (p > 0.05). However, insemination of neuraminidase-treated Brown Leghorn sperm decreased the y-intercept by 31.6 percentage units (p < 0.001). Therefore, sialyl residues in the spermatozoal glycocalyx affect the extent of spermatozoal sequestration following intravaginal insemination.