Comparative study between silymarin (Silybum Marianum), melatonin and a combination of them for improving frozen sperm properties of Holstein Bulls Born in Iraq

Abstract

This study aims to identify whether adding silymarin and melatonin separately or together to the tris diluent in maintaining the fertile viability of the sperm after cooling and freezing in liquid nitrogen. Semen was collected by artificial vagina from Holstein bulls born in Iraq and diluted by Tris-Citrate-Fructose egg yolk diluents. Diluted spermatozoa was treated with tris diluent without any addition (control), silymarin 0.018gm/50ml tris (T1), combination of silymarin and melatonin (T2) and melatonin 0.05gm/100ml tris alone (T3), and packaged in 0.25 ml straws, which were further cooled to 5°C before freezing in liquid nitrogen, and the progressive motility%, dead sperm%, abnormality% and acrosome defects% were assessed after cooling and freezing. Thawing was carried out at 37°C for 30 sec. The results indicate that the addition of silymarin and melatonin had a role in improving and maintaining the sperm properties whether after cooling or freezing, but silymarin was better than melatonin alone or combination of them in reducing sperm damage after cooling and freezing. The results also showed that freezing had a negative effect on the sperm properties, but it was less or no effect of the diluent contain silymarin alone.