title: Modification of the ethidium bromide exclusion procedure for evaluation of turkey semen.
abstract: The objective of the present study was to modify the ethidium bromide exclusion procedure in order to detect dead and labile turkey spermatozoa after 24 h storage at 7 C. In Experiment 1, fresh and stored spermatozoa were suspended in phosphate-buffered saline (PBS) ranging in osmolarity from 296 to 3 mOsm/kg H2O, each solution containing the same concentration of the nuclear fluorochrome ethidium bromide. In the 3 mOsm/kg H2O PBS, nearly all the fresh (98.3%) and stored (96.7%) spermatozoa were stained with ethidium bromide, indicating they were nonviable. Fresh spermatozoa revealed minor variation in the percentage of nonviable spermatozoa in the ethidium bromide exclusion procedure (ethidium bromide in PBS at 296 mOsm/kg H2O) (20.9%) and the remaining hypotonic PBS solutions (range 20.4 to 18.9%). In the stored semen samples a previously undetected subpopulation of more labile spermatozoa became apparent in hypotonic solutions with osmolarities of 122 and 56 mOsm/kg H2O. In Experiment 2, hen fertility was determined using fresh and stored semen. All hens were inseminated with 100 x 10(6) viable spermatozoa. Viability of stored semen was determined either by the original ethidium bromide exclusion procedure or using the sperm-stress test (ethidium bromide in PBS at 56 mOsm/kg H2O). The observations showed that adjusting the number of viable spermatozoa inseminated based on the percentage of viable sperm estimated from the sperm-stress test did not improve hen fertility over a 15-wk egg production period.
authors.affiliation: USDA, Avian Physiology Laboratory, Beltsville, Maryland 20705.
authors.forename: M R
authors.initials: MR
authors.lastname: Bakst
authors.forename: H C
authors.initials: HC
authors.lastname: Cecil
authors.forename: T J
authors.initials: TJ
authors.lastname: Sexton
mesh_terms: D000818:Animals; D004996:Ethidium; D005260:Female; D005298:Fertility; D007038:Hypotonic Solutions; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D012661:Semen / Q000502:physiology*; D012662:Semen Preservation / Q000662:veterinary*; D013081:Sperm Motility; D014422:Turkeys / Q000502:physiology*
chemical_list: D007038:Hypotonic Solutions; D004996:Ethidium