Effect of Phenylephrine, Ergonovine, Oxytocin and Norepinephrine as an Extender Ingredient on Viability of Bovine Spermatozoa

Abstract

We evaluated effects of three concentrations of phenylephrine, ergonovine, oxytocin and norepinephrine (myometrial stimulants) on viability of spermatozoa when they were included in a seminal extender. Using a split ejaculate technique, ejaculates from each of 10 bulls were extended in egg-yolk citrate to a final concentration of 35 x 10(6) sperm/ml, including 20 mg/ml, 2 mg/ml and .2 mg/ml, of phenylephrine or ergonovine, 20 IU/ml, 2 IU/ml and .2 IU/ml oxytocin or 200 micrograms/ml, 20 micrograms/ml and 2 micrograms/ml norepinephrine prior to freezing. Extended semen without a myometrial stimulant served as the control. Percentage of intact acrosomes was determined prior to freezing for all treatments. Motility and percentage of intact acrosomes were determined immediately after thawing (0 h) and again after 4 h incubation at 37 degrees C. Percentage of intact acrosomes was reduced (P less than .05) prior to freezing by phenylephrine (20 mg/ml) and ergonovine (20 mg/ml) (phenylephrine = 56%; ergonovine = 63%; control = 74%). The same doses of phenylephrine and ergonovine reduced (P less than .05) post-thaw motility and percentage of intact acrosomes at both 0 and 4 h compared with controls. Sperm exposed even to the intermediate concentration (2 mg/ml) of ergonovine had lower (P less than .05) motility 4 h post-thaw. No other compound or concentration of compound or concentration of compound affected percentage of intact acrosome or motility. There were no two or three-way bull x compound and concentration interactions (P greater than .2).(ABSTRACT TRUNCATED AT 250 WORDS)