Effect of egg yolk powder on freezability of Murrah buffalo (Bubalus bubalis) semen

Aim: The aim of this study was to investigate the effect of commercial egg yolk powder as an alternative to fresh egg yolk on freezability of Murrah buffalo semen. Materials and Methods: Semen samples (12) from 3 Murrah buffaloes (4 from each bull) with mass motility (≥3+) and total motility (70% and above) were utilized in this study. Immediately after collection, each sample was divided into four groups. Groups I was diluted up to 60×106 sperm/ml with tris extender containing 10% fresh egg yolk and Groups II, III, and IV were diluted up to 60×106 sperm/ml with tris extender containing 2%, 4%, and 6% egg yolk powder, respectively. Semen samples were processed and cryopreserved followed by examination of frozen semen samples after 24 h. Semen samples from each group were evaluated for total motility, viability, acrosomal integrity, abnormality, and hypo-osmotic swelling test (HOST) response after dilution, pre-freeze, and post-thaw stage. Results: Pre-freeze total motility was significantly (p<0.05) higher in Groups III and IV as compared to Groups I and II, and post-thaw total motility was significantly (p<0.01) higher in Group III as compared to other three groups. Viability was significantly (p<0.05) higher in Groups II, III, and IV than Group I at the pre-freeze stage. Significantly (p<0.01) higher viability and acrosomal integrity were recorded in Group III as compared to other three groups at the post-thaw stage. Abnormality was significantly (p<0.05) higher in Group IV than other three groups. HOST response was significantly (p<0.05) higher in Groups II and III than Groups I and IV at the pre-freeze and post-thaw stages. Conclusion: Addition of egg yolk powder at 4% level yielded significantly better results in terms of post-thaw semen quality as compared to the fresh egg yolk and other concentrations of egg yolk powder (2% and 6%).