Osmolarity of Coconut Water (Cocos nucifera) Based Diluents and their Effect Over Viability of Frozen Boar Semen

Problem statement: Boar sperm cells are sensitive to the freezing process, which compromises viability of frozen-thawed sperm. In a constant search for minimizing or suppressing sperm cell damage caused by the temperature and osmolarity changes during the freezing process, crioprotective and antioxidant substances have been added to the freezing media, such as coconut water, in order to increase the viability of frozen-thawed swine semen. The addition of any substance to the freezing diluent, directly affects osmolarity of the media, which can have positive or negative effects over the sperm cell. Approach: There are no published studies currently that indicate the effect of adding coconut water over the osmolarity of freezing media and their effect over viability of sperm cells, therefore, the objective of the present study was to evaluate the effect of coconut water based diluents osmolarity over the Motility (Mot), Acrosome Integrity (AI), Membrane Integrity (MI) and Mitochondrial Activity (MA) of thawed boar sperm cells. The treatments used were control T1 (LEY with bidistilled water + LEYGO) with an osmolarity range of 296-368 mOsmol Kg^-1, T2 (LEY and deionized coconut water + LEYGO) between 381 and 480 mOsmol Kg^-1 and T3 (LEY and in natura coconut water + LEYGO) between 519 and 1041 mOsmol Kg^-1. The Westendorf modified method was the freezing method used. The obtained data were statistically analyzed by GLM, using the SAS software (SAS, 2000). Results: A significant difference was observed on T2 compared to T1 regarding Mot 41.9 Vs 36.9% and MI 58.0 Vs 50.2. T3 had a detrimental effect on all studied variables. Conclusion: Under our study conditions, the osmolarity range of T2, due to the non ionic solutes content, contributed to improve the viability of frozen-thawed sperm cells.