SEASONAL VARIATION IN HEAT SHOCK PROTEINS (HSP70 AND HSP90) AND THEIR ASSOCIATION WITH FROZEN SEMEN QUALITY AND FERTILITY IN BUFFALOES

摘要

BACKGROUND: Heat shock protein is considered as a potential indicator of animal adaptation to harsh environmental stresses and its expression has been correlated with resistance to stress. OBJECTIVE: To evaluate the seasonal variation in heat shock proteins (hsp70 and hsp90) and their association with frozen semen quality and fertility in buffaloes. MATERIALS AND METHODS: During summer and winter, ejaculates (n = 32) were collected from buffalo bulls, diluted with freshly prepared Andromed extender (maintained at 34 degrees C) up to 80 million sperm per mL. The diluted semen was filled in French midi straws, equilibrated, and cryopreserved. The semen was evaluated at pre-freeze and post-thaw stages for heat shock proteins (HSP70 and HSP90), and sperm quality parameters. RESULTS: The levels of HSP70 were significantly (P = 0.00) higher in summer season compared to winter season. The HSP70 had a positive correlation with mass motility (P < 0.05; r = 0.39), live sperm count (P < 0.05; r = 0.47), and acrosomal integrity (P < 0.05; r = 0.37). The first artificial insemination conception rate (FAICR) had a positive correlation with HSP70 (P < 0.05; r = 0.47), and HSP90 (P < 0.05; r = 0.59), in frozen-thawed semen. CONCLUSION: The assessment of the levels of heat shock proteins may help in predicting cryo-tolerance and fertility of buffalo semen during various seasons.