Effects of supplementation of iodixanol to semen extender on quality and fertilization ability of frozen–thawed Thai native bull sperm

Abstract

This study investigates the effects of iodixanol supplementation in varied concentrations to Tris egg yolk (TEY) extender on the quality and fertilization ability of frozen-thawed sperm of Thai native bulls. Each ejaculate was divided into four different groups, as follows: sperm were treated with TEY extender (control group) and TEY extender supplemented with three different concentrations of iodixanol (1.25%, 2.50% and 5.00%). Semen straws were frozen in liquid nitrogen vapor. After thawing, sperm motility characteristics, viability, plasma membrane integrity and acrosome integrity were determined. Also, frozen-thawed spermatozoa from all groups were used for in vitro fertilization and artificial insemination (AI) in natural estrus Thai native cows. The results showed that the post-thaw quality of the 2.50% iodixanol group was superior to the other iodixanol groups (P < 0.05). However, iodixanol had no beneficial effect on post-thaw sperm in vitro fertilization ability and pregnancy rate after AI (P > 0.05). It can be concluded that the supplementation of 2.50% iodixanol extender significantly improves the progressive motility, viability, plasma membrane integrity and acrosome integrity of cryopreserved semen from Thai native bulls, but it has no beneficial effect on in vitro fertilization ability and pregnancy rate after AI.

Iodixanol supplementation in freezing extender improves the antioxidant capacity of semen

“…Regarding the G3, although it did not differ from G6 for almost all semen quality parameters, this iodixanol concentration was not effective for providing greater longevity to the sperm. Similarly, other authors reported that 5% (final concentration 3%, v/v) is potentially toxic to bull and buffalo sperm (Chuawongboon et al, 2017; Saragusty et al, 2009; Swami et al, 2017a) although this concentration was optimal for freezing ram semen (Cirit et al, 2013). According to Chuawongboon et al (2017), the toxicity of higher doses of iodixanol is related to an increase in the osmolarity of extracellular solution, which was not observed in this study with G6.…”

“…Similarly, other authors reported that 5% (final concentration 3%, v/v) is potentially toxic to bull and buffalo sperm (Chuawongboon et al, 2017; Saragusty et al, 2009; Swami et al, 2017a) although this concentration was optimal for freezing ram semen (Cirit et al, 2013). According to Chuawongboon et al (2017), the toxicity of higher doses of iodixanol is related to an increase in the osmolarity of extracellular solution, which was not observed in this study with G6. The osmotic strength of commercial iodixanol solution is 170 mOsm/kg, thus any addition of this substance would maintain or reduce the extracellular osmolarity and, consequently, the damage from the high‐osmolarity effect (Saragusty et al, 2009).…”

“…The osmotic strength of commercial iodixanol solution is 170 mOsm/kg, thus any addition of this substance would maintain or reduce the extracellular osmolarity and, consequently, the damage from the high‐osmolarity effect (Saragusty et al, 2009). Therefore, the synergism between the iodixanol solution (RedCushion®) and the freezing extender compounds (BotuBov®) could explain the contradictory results, since previous reports (Chuawongboon et al, 2017; Saragusty et al, 2009; Swami et al, 2017a) used a different iodixanol solution (OptPrep®) added to different freezing extenders (Andromed®, Tris‐egg yolk and Optixcell®, respectively).…”

“…In addition, Saragusty et al (2009) using iodixanol for cushion centrifugation to prepare semen for cryopreservation observed that this substance could have cryoprotective effects. Therefore, some studies have emerged with the purpose of evaluating the cryoprotective effects of this substance in bovine (Chuawongboon et al, 2017; Saragusty et al, 2009), buffalo (Swami et al, 2017a; Yadav et al, 2017), ram (Cirit et al, 2013), and dog semen (Abdillah et al, 2019). Indeed, these studies demonstrated that adding iodixanol to semen freezing extender improved the post‐thaw semen quality by protecting the integrity and functionality of sperm membranes and preserving their motility throughout cryopreservation (Cirit et al, 2013; Saragusty et al, 2009; Swami et al, 2017a; Yadav et al, 2017).…”

Trehalose addition to a Tris-fructose egg yolk extender on quality of ram sperm preserved at 0 °C

“…During the sperm treatment, trehalose binds to the sperm cell membrane, which reduces the damage of the sperm caused by dehydration and the damage to the acrosomal and plasma membranes, thus stabilizing sperm cell membrane structure (Nayernia et al, 2002;Zhu et al, 2017). The proteolytic enzymes (acrosome enzymes) existing in sperm acrosomes are critically involved in the fertilization process (He et al, 2016;Chuawongboon et al, 2017). The detection of the acrosome integrity can indirectly reflect the sperm function, which is of great significance in the evaluation of abnormal sperm function and artificial insemination effectiveness.…”