EFFECT OF ADDING PENTOXIFYLLINE AND NITRIC OXIDE TO TRIS EXTENDER ON SOME POST-CRYOPRESERVED SEMEN ATTRIBUTES OF HOLSTEIN BULLS

Abstract

This study was aimed to explore the effect of adding pentoxifylline (PTX) and nitric oxide (NO) to Tris extender on some post-cryopreserved semen attributes of Holstein bulls for different preservation periods (cooling at 5◦C, 48 hrs., 1, 2 and 3 months post cryopreservation, PC). Seven Holstein bulls of 2.5-3 years old were used in the current study during the period from 20^th November, 2017 to 20^th August, 2018. Pooled semen was equally divided into three groups within one experiment. PTX (0.192 g / 100 ml extender) and NO (0.018 g / 100 ml extender) were added to Tris extender and comparisons in response were made with the control group (Tris extender, C). The PTX group exhibited greater (P≤ 0.01) sperm's cell individual motility percentage as compared with the C group at cooling (5ºc) and 48 hr PC periods, while, PTX and NO groups were superior in these percentages at the remaining PC periods than C group. Excluding data of 2 months PC, greater (P≤ 0.01) live sperm percentage was observed in PTX and NO groups in comparison with the C group at all preservation periods. Lesser (P≤ 0.01) abnormal sperm percentage were noticed for PTX and NO groups as compared with the C group at all preservation time periods. The PTX and NO groups exhibited greater   (P≤ 0.01) acrosome and plasma membrane integrity percentages in comparison with the C group at all preservation time periods. In conclusion, adding PTX and NO to Tris extender enhanced some of  PC semen characteristics of Holstein bulls at different preservation periods.