title: Effect of equilibration times, freezing, and thawing rates on post-thaw quality of buffalo (Bubalus bubalis) bull spermatozoa.
abstract: The effects of equilibration times (E1, 2 h; E2, 4 h; E3, 6 h), freezing rates (FR1, manual, 5 cm above liquid nitrogen (LN2 ) for 10 min, plunging in LN2 ; FR2, programmable ultra-fast, holding at +4 °C for 2 min, from 4 to -10 °C at -10 °C/min, from -10 to -20 °C at -15 °C/min, from -20 to -120 °C at -60 °C/min, holding at -120 °C for 30 sec, plunging in LN2 ), and thawing rates (T1, 37 °C for 30 sec; T2, 50 °C for 15 sec; T3, 70 °C for 7 sec) were evaluated on quality of buffalo bull spermatozoa. Progressive motility (%), rapid velocity (%), average path velocity (VAP, μm/s), straight line velocity (VSL, μm/s), and mitochondrial transmembrane potential (%) were higher (p < 0.05) with E2, FR2, and T3 compared to other groups. Sperm curved line velocity (VCL, μm/s) was higher (p < 0.05) with E2 and FR2 compared to other groups. Sperm straightness (%) and linearity (LIN, %) were higher (p < 0.05) with E2 compared to other groups. Sperm LIN was affected (p < 0.05) with T3 compared to other groups. Supravital-plasma membrane integrity (%), viability and acrosome integrity (%) of spermatozoa were higher (p < 0.05) with E2 and FR2 compared to other groups. Sperm DNA integrity (%) was higher (p < 0.05) with FR2 and T1 compared to other groups. We concluded that inclusion of 4 h-equilibration time, programmable ultra-fast freezing rate, and rapid thawing at 70 °C for 7 sec in cryopreservation protocol improves the post-thaw quality of buffalo bull spermatozoa.
authors.affiliation: Animal Reproduction Laboratory, Animal Sciences Institute, National Agricultural Research Center, Islamabad, Pakistan.|Laboratory of Animal and Human Physiology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: S A H
authors.initials: SA
authors.lastname: Shah
authors.affiliation: Animal Reproduction Laboratory, Animal Sciences Institute, National Agricultural Research Center, Islamabad, Pakistan.
authors.forename: S M H
authors.initials: SM
authors.lastname: Andrabi
authors.affiliation: Laboratory of Animal and Human Physiology, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: I Z
authors.initials: IZ
authors.lastname: Qureshi
mesh_terms: D000818:Animals; D002020:Buffaloes; D015925:Cryopreservation / Q000379:methods*; D004249:DNA Damage; D005615:Freezing; D008297:Male; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology*
keywords: buffalo bull; equilibration times; freezing rates; mitochondrial transmembrane potential; spermatozoa; supravital-plasma membrane integrity; thawing rates; viable and intact acrosome