Assessment of Quality of Poultry Sperm

The poultry industry is dependent on efficient reproduction. Reproduction of broiler lines increasingly is a problem and already is limiting for turkeys. Currently, breeders or producers can identify males of low fertility only retrospectively after a costly failure. However, elimination of the 25-35% of males likely to be of lowest fertility before they were turned in with hens would increase fertility by 10 percentage units. Such culling presently is impossible because there is no simple, low cost test which is reasonably predictive of fertility of a rooster or turkey tom. This project will develop an assay for field measurement of the combined attribute of sperm motility plus sperm binding to a substrate prepared from a purified extract from unfertilized chicken eggs. The assay to be developed mimics, in vitro, the initial binding of a rooster spermatozoon to the vitelline membrane of an unfertilized hen's egg. Early preliminary data demonstrate a strong relationship (r^2 = 0.81) between sperm binding to the microwell used for a prototype assay and fertility of the same semen. Two Objectives will be addressed in Phase I. Sperm from roosters of unknown fertility or from lines selected for high or low fertility will be used in 3 experiments with the goal of developing a repeatable and sensitivity fluorescent, microwell sperm-binding assay. The 4th experiment will demonstrate feasiblity of the assay by showing, in a predictive manner, that roosters designated as "bad" or "good" on the basis of the newly developed assay differ in fertility and that, for a simulated population, sperm binding is predictive of fertility.