THE INTEREST OF HYPEROSMOLAR EXTENDERS IN ROOSTER SPERM CRYOPRESERVATION

The aim of the present study was to investigate thepotential benefit of hyperosmolar extender during the freezing-thawing process in rooster sperm. The goal was to minimize the amount of intracellular water and reduce the impact of intracellular icecrystal during the freezing process. A total of five 45-week old Hubbard commercial broilers were subjected to bi-weekly semen collections. Collected sperm was pooled and divided in three aliquots. The control aliquot was diluted with Tris-extender without further supplementation at 300 mOsm (Control). The two (2) other aliquots were diluted with Trisextender at 300 mOsm containing vitamin E (Vit E) or with Tris-extender without Vitamin E but at osmolarity of 450 mOsm (Hyper). After incubation at 22 °C for 15 min, all aliquots were cooled and then frozen in liquid nitrogen. A Computer Aided Semen Analysis (CASA) was used to investigate the impact on different motility parameters. After thawing, Hyperosmolar (Hyper) and vitamin E extenders showed the highest values in terms of sperm motility preservation. Hyperosmolar extender (Hyper) showed particularly the highest values in terms of VSL velocities and progressive motile spermatozoa, known as indicators of sperm quality. In conclusion, the present results revealed that a significant impact was observed when using extenders at osmolarity of 450 mOsmin rooster sperm, in the same manner and even better then when using vitamin E. The positive impact is probably related to the reduction of intracellular ice formation.