Effects of coconut (Cocos nucifera) water with or without egg-yolk on viability of cryopreserved buck spermatozoa

Abstract

The effects of semen extenders containing coconut (Cocos nucifera) water alone or combined with egg yolk on viability of spermatozoa during cryopreservation of semen obtained from West African Dwarf (WAD) bucks were studied. Coconut water (5, 10, 15 and 20 ml/100 ml) was diluted with pooled semen samples in study I, while in study II, the pooled semen samples were diluted with egg yolk and coconut water (EYCW) at 5:10, 10:10 and 10:5 in Tris-based extenders. The control consisted of Tris-based extenders plus sodium citrate. The diluted semen samples were cryopreserved for 30 days and evaluated for sperm viability parameters. Following cryopreservation, acrosome reaction and capacitation of spermatozoa were induced in vitro. The results showed that motility was higher (P < 0.05) in coconut water extenders compared to the control and improvement in this parameter was best at 10% coconut water. More spermatozoa cryopreserved with coconut water underwent induced acrosome reaction and capacitation compared to the control and 10% coconut water had the highest values (P < 0.05). The results showed that motility was better preserved in EYCW5:10 and EYCW10:10 extenders (P < 0.05). While more spermatozoa underwent induced acrosome reaction and capacitation with coconut water and egg yolk extenders at different combinations compared to the control (P < 0.05), the highest values of acrosome integrity and membrane integrity were observed in EYCW5: 10 extenders. The results revealed that 10% coconut water and EYCW5:10 gave better improvement of sperm viability parameters. The findings indicated that coconut water extender improved the quality of cryopreserved spermatozoa of WAD bucks.