Effect of adding aqueous extract of Melissa officinalis leaves and some other antioxidants to Tris extender on post-cooling and post- cryopreservative plasma membrane and acrosome integrity percentages of Holstein bulls

Abstract

This study was conducted to explore the effect of adding aqueous extract of Melissa officinalis leaves (AEMOL), some antioxidants to Tris extender on sperm’s plasma membrane and acrosome integrity for Holstein bulls following different preservation periods. The study was executed at the Department of Artificial Insemination, Abu-Ghraib belong to the Directorate of Animal Resource, Ministry of Agriculture, during the period from October 2015 to February 2016 using ten Holstein bulls of 2.5-3 years old. Semen was collected via artificial vagina in one ejaculate per bull per week for the 7-week experimental period. Pooled semen was equally divided into ten groups using Tris extender. In this experiment, AEMOL (0.062mg/100 ml; A2), WEMOL (0.062mg/100 ml) + 5 mM of vitamin C (A3), AEMOL (0.062mg/100 ml + 0.08 mM of Trolox (A4), AEMOL (0.062mg/100 ml + 100 IU of catalase (A5),100 IU of catalase (A6), 5 mM of vitamin C (A7), 0.08 mM of Trolox (A8), 0.2 mM of vitamin E (A9) and AEMOL (0.062mg/100 ml +0.2 mM of vitamin E (A10) and comparisons in response were made with the control group (Tris extender, A1). The effect of these additives on semen characteristics of Holstein bulls for different preservation periods (cooling at 5◦C, 48 h, 1, 2 and 3 months post cryopreservation, PC) were studied. The A2 group exhibited greater (P≤0.01) plasma membrane and acrosome integrity percentage as compared with A1 group at all preservation time periods. Greater (P≤ 0.01) plasma membrane and acrosome integrity percentage were noticed in comparison with the A1 group at all preservation time periods. On the other hand, A5 group exhibited greater (P≤ 0.01) plasma membrane and acrosome integrity percentage, as well as, Adding of vitamin E alone (A9) or combined with AEMOL (A10) to Tris extender had positive (P≤ 0.01) effect in improving all the semen characteristics at all preservation time periods. In conclusion, adding of AEMOL as alone or combined with the other synthetic antioxidants to Tris extenders had a crucial role in improving PC sperm's plasma membrane and acrosome integrity percentage of Holstein bulls. This was reflected positively in increasing pregnancy rates of the inseminated cows and owner's income consequently.