摘要
Objective:To explore the effect of BHT on cattle spermatozoa during cooling and cryopreservation.Methods: Pooled bull semen were diluted by Tris-Citrate-Fructose egg yolk (TCFY) diluent considered as control (0 BHT) and different concentrations of BHT (1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 mM were prepared in ethanol in prewarmed (37℃) test tubes. The ethanol was allowed to evaporate so that, a thin crystallized layer of BHT was deposited on the inner surface of the tubes. Then extended semen was added into the tubes and incubated at 37℃ for 5 min to allow uptake of BHT by spermatozoa. The tubes were cooled slowly (approximately for 2 h) up to 5℃ and equilibrated for 4 h. After equilibration, semen freezing process was carried out. Extended semen was subjected to evaluation (motility, alive sperm, intact sperm membrane (HOST) % and acrosome integrity) in both cooled and cryopreserved semen. Results:The result revealed that sperm motility of post-cooled spermatozoa improved (P<0.05) by the use of BHT concentrations (1, 2 and 3 mM) in Tris semen extender if compared to the control (85.00±1.09), (83.33± 0.63), (81.67± 0.63) and (78.33± 0.63), respectively. Alive sperm percent was significantly higher in all concentrations of BHT. Sperm abnormalities percent were significantly lower in concentrations of BHT 1 and 2 (11.2±0.2), (11.8±0.2)and (13.4±0.4), respectively. Sperm membrane integrity were significantly higher in BHT concentrations (1, 2, 3, 4 and 5 mM). It is exhibited that improved sperm motility in post-thawed frozen semen in the concentrations of BHT (1, 2, 3 and 4 mM) if compared to the control. The sperm membrane integrity were significantly improved at all concentrations of BHT. Acrosome integrity was significantly higher at BHT concentration 1 mM (81.80±0.57) and (76.00±2.05), respectively.Conclusions: It could be concluded that some concentrations of BHT improved bull semen quality post-cooling and post-freezing.
