Research articleChicken egg yolk plasma in tris-citric acid extender improves the quality and fertility of cryopreserved water buffalo (Bubalus bubalis) spermatozoa

This study was primarily designed to evaluate the effect of different concentrations of ultraviolet (UV)-C-irradiated chicken egg yolk plasma (EYP; v:v; 10%, P1; 15%, P2; 20%, P3) or 20% (v:v) of whole chicken egg yolk (WCEY) in tris-citric acid (TCA) extender on water buffalo sperm quality during cryopreservation (postdilution, PD; postequilibration, PE; post-thawing, PT). Also the effect of best evolved concentration of UV-C-irradiated EYP in extender on in vivo fertility of buffalo spermatozoa was evaluated. At PE and PT, computer-assisted sperm analysis progressive motility (PM, %) was significantly higher in P3 compared with P1 and WCEY. Rapid velocity (RV, %) was higher (P < 0.05) in P3 compared with P1 and WCEY during cryopreservation (PD, PE, and PT). Average path velocity (μm/s) and straight line velocity (μm/s) were higher (P < 0.05) in P2 and P3 than WCEY at PE and PT. The decline percentage (%, longevity) in PM and RV was lower (P < 0.05) in P3 compared with WCEY during 2 hours incubation under in vitro condition at PT. Supravital plasma membrane integrity (%) was higher (P < 0.05) in P2 and P3 compared with control at different stages (PE and PT). Mitochondrial transmembrane potential (%) was higher (P < 0.05) in P2 and P3 compared with P1 and WCEY at different stages (PD and PT). Percentage of viable sperm with intact acrosome, and sperm DNA integrity (%) were higher (P < 0.05) in P2 and P3 compared with WCEY at PT. The in vivo fertility rate (%) was significantly higher with P3 compared with WCEY (76.61 vs. 64.49). In conclusion, WCEY (20%) can be replaced with UV-C-irradiated chicken EYP (20%) in TCA extender for cryopreservation of water buffalo spermatozoa.