Sperm mobility: phenotype in roosters (Gallus domesticus) determinedby concentration of motile sperm and straight line velocity.
Previous research demonstrated that sperm mobility, i.e., the net movement of a sperm population, is a quantitative trait of the domestic fowl. However, the cellular basis for this trait was unknown. In the present work, individual motile sperm were evaluated with a Hobson SpermTracker in order to identify one or more properties of motile sperm that could account for variation in sperm mobility observed among males. A method was validated for assessing sperm motion over an erythrocyte monolayer at body temperature. A small-scale experiment with roosters from the tails and center of a normal distribution of sperm mobility phenotypes (n = 33 roosters) demonstrated that straight line velocity (VSL) and motile concentration were critical to expression of phenotype. The importance of these variables was confirmed with a large-scale experiment using a representative subpopulation (n = 100 roosters). VSL of individual sperm at 41 degrees C ranged between 5 and 100 microm/sec. VSL averaged 32, 39, and 40 microm/sec for low, average, and high sperm mobility phenotypes. Sperm were diluted to 1.2 x 10(6)/ml for motion analysis. Mean motile concentrations were 0.52, 0.84, and 0.95 x 10(6)/ml for low, average, and high sperm mobility phenotypes. Motile concentration was correlated with sperm mobility (r = 0.71). VSL appeared to have an additive effect as it was correlated with straightness of sperm cell trajectory (r = 0.79).
Froman
D P
DP
Department of Animal Sciences, Oregon State University, Corvallis, Oregon 97331, USA. david.froman@orst.edu
Feltmann
A J
AJ
D000818:Animals; D001831:Body Temperature / Q000502:physiology; D002478:Cells, Cultured; D002645:Chickens / Q000502:physiology*; D004912:Erythrocytes / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D010641:Phenotype; D013081:Sperm Motility / Q000502:physiology*; D013082:Sperm Tail / Q000502:physiology / Q000648:ultrastructure; D013094:Spermatozoa / Q000502:physiology* / Q000648:ultrastructure; D013696:Temperature