Cryopreservation of Indian red jungle fowl (Gallus gallus murghi) semen with polyvinylpyrrolidone

The Indian red jungle fowl is a sub-species of the genus Gallus native to South Asia; facing high risk of extinction in its native habitat. During cryopreservation, permeable cryoprotectants like glycerol are usually employed and we previously showed encouraging results with 20% glycerol. Because bird spermatozoa contain very little intracellular water, the possibility of replacing an internal cryoprotectant by an external one is opened. In the present study, we tested the replacement of internal cryoprotectant glycerol by the external cryoprotectant Polyvinylpyrrolidone (PVP). PVP is a non-permeable cryoprotectant and keeps the sperm in glassy state both in cooling and warming stages without making ice crystallization within the sperm cell. We evaluated the effect of various levels of polyvinylpyrrolidone (PVP) on Indian red jungle fowl semen quality and fertility outcomes. The qualifying semen ejaculates collected from eight mature cocks were pooled, divided into five aliquots, diluted (37 °C) with red fowl semen extender having PVP [0% (control) 4% (w/v), 6% (w/v), 8% (w/v) and 10% (w/v)]. Diluted semen was cryopreserved and stored in liquid nitrogen. The whole experiment was repeated/replicated for five times independently. Sperm motility, plasma membrane integrity, viability and acrosome integrity were recorded highest (P < 0.05) with 6% PVP at post-dilution, cooling, equilibration and freeze-thawing. Higher (P < 0.05) no. of fertile eggs, fertility, no. of hatched chicks, percent hatch and hatchability was recorded with 6% PVP compared to control. It is concluded that 6% PVP maintained better post-taw quality and fertility of Indian red jungle fowl spermatozoa than glycerol and can be used in routine practice avoiding the contraceptive effects of glycerol.