Effect of different levels of egg-yolk on freezability of Jakhrana buck semen.

The present study was designed to determine the effect of different levels of egg-yolk on freezability of Jakhrana buck semen. Six healthy Jakhrana bucks (BW=30 ± 2kg, age=12 ± 0.5 month) were used for semen collection. These bucks were maintained under semi-intensive system at Jakhrana Unit of C.I.R.G. Makhdoom, Mathura. A total of 48 ejaculates (6 bucks x 8 replicates) were collected twice a week using artificial vagina. Each ejaculate was divided into 4 groups (G1, G2, G3 and G4). The G1, G2, G3 and G4 were extended with Tris-egg yolk-citric acid- fructose-glycerol (TEYCFG) extenders containing 5, 10, 15 and 20% egg yolk level, respectively. Each ejaculate was evaluated for sperm motility, viability, abnormality, and hypo-osmotic swelling (HOS) response and acrosome integrity before and after freezing. At pre-freeze stage no significant (P>0.05) difference in sperm motility and viability was found among all groups. Sperm abnormality was significantly (P<0.05) higher in G4 as compared to other groups (G1, G2, G3). The HOS response and acrosomal integrity was significantly (P<0.05) higher in G1, G2 and G3 as compared to G4. However, no significant (P>0.05) difference was observed in HOS response and acrosomal integrity among G1, G2 and G3. At post thaw stage, sperm motility, viability and HOS response was significantly (P<0.05) higher in G1 and G2 as compared to G3 and G4. Sperm abnormality was significantly (P<0.05) lower in G2 as compared to other groups. The acrosomal integrity was significantly (P<0.01) higher in G1 and G2 as compared to G3 and G4. It is concluded that 10% egg yolk in Tris based extender may be the best for successful cryopreservation of Jakhrana buck semen. [ABSTRACT FROM AUTHOR]