INCREASED FECUNDITY RESULTING FROM SEMEN DONOR SELECTION BASED UPON IN-VITRO SPERM MOTILITY

Semen donors were selected from a population of 100 roosters based upo n the extent to which sperm penetrated 6% (wt/vol) Accudenz((R)) from an overlay of extended semen. Semen donors categorized by average or h igh sperm motility (n = 5 per phenotype) were ejaculated weekly, their ejaculates pooled by phenotype, and pooled semen extended. A subsampl e of each sperm suspension was overlaid on 6% (wt/vol) Accudenz((R)) i n a cuvette, the cuvette was placed in a 41 C water bath, and the abso rbance of the Accudenz((R)) layer was measured after a 5-min incubatio n. The remainder of the sperm suspension was inseminated (n = 55 hens per phenotype). Each hen was inseminated weekly with 50 x 10(6) sperm for 14 wk. The hatchability of eggs laid by hens inseminated with sper m from the high motility phenotype was 10% greater (P less than or equ al to 0.001) than that of hens inseminated with sperm from the average phenotype. The difference in fecundity was explicable in terms of fer tility (P less than or equal to 0.001). A replicate experiment tested the effect of sperm motility as well as insemination dose on fertility . Roosters were treated as above, and hens (n = 41 to 45 per phenotype ) were inseminated weekly with 25, 50, or 100 x 10(6) sperm per hen fo r 3 wk. Two-way ANOVA detected a sperm motility effect (P less than or equal to 0.0001) but did not detect a dose effect (P greater than or equal to 0.05) or a motility by dose interaction (P greater than or eq ual to 0.05). A posteriori comparison among means revealed that the ma ximal fertility obtained with sperm from average roosters was 9% less (P less than or equal to 0.05) than that obtained with only 25% as man y sperm from the high motility phenotype. These experiments demonstrat ed that the fecundity of artificially inseminated hens can be increase d when sperm penetration of Accudenz((R)) is used as a selection crite rion for semen donors.