Freezability of water buffalo spermatozoa is improved with the addition of catalase in cryodiluent.

BACKGROUND: Catalase enzyme is usually distributed in mammalian seminal plasma, where it decomposes hydrogen peroxide into water and oxygen and enhances sperm survivability. OBJECTIVE: To evaluate the effect of catalase (0, 100, 200 or 300 IU/ml) added in tris-citric acid (TCA) based extender on motion characteristics, viability and DNA integrity of bubaline spermatozoa at post dilution (PD) and post thawing (PT) stages of cryopreservation. MATERIALS AND METHODS: Collection of semen was done in four Nili-Ravi bulls with an artificial vagina (42 degree C). Qualified semen samples from each bull were further subdivided into four aliquots for dilution with the experimental TCA extender containing either 0.0 (T1), 100 IU (T2), 200 IU (T3) or 300 IU (T4) catalase (activity12660 U/mg). RESULTS: At PT, mean computer progressive motility, average path velocity, straight line velocity, curvilinear velocity, visual motility and DNA integrity were higher (P < 0.05) in catalase fortified treatment groups as compared with control. Regarding plasma membrane integrity and supra-vital plasma membrane integrity, at PT the mean values were higher (P < 0.05) in T4 as compared with control. At PD and PT, mean acrosomal integrity of buffalo bull spermatozoa was higher (P < 0.05) in T4 group as compared with control. CONCLUSION: Addition of catalase at a concentration of 300IU/ml in TCA cryodiluent improved the freezability of water buffalo spermatozoa.

Determination of an Optimal Membrane-permeable Cryoprotectant Addition and Dilution Protocol for Water Buffalo Spermatozoa.

BACKGROUND: There is a possibility to reduce the toxicity of glycerol and osmotic stress of DMSO by lowering their concentrations in freezing extenders. OBJECTIVE: To investigate the effect of glycerol and DMSO in tris-citric acid based extender on post- thaw quality of buffalo (Bubalus bubalis) bull spermatozoa. MATERIALS AND METHODS: Semen was collected from five adult buffalo bulls with artificial vagina. Five aliquots of semen per bull were separated for dilution with the treatment extenders. The first aliquot was diluted at 37C with 6 percent glycerol (T1). The second aliquot was diluted at 37C with extenders containing 4.5 percent glycerol and 1.5 percent DMSO (T2). The third aliquot was diluted with extenders containing 4.5 percent glycerol at 37C and 1.5 percent DMSO at 4С (T3). The fourth aliquot was diluted with extenders containing 1.5 percent DMSO at 37C and 4.5 percent glycerol at 4С (T4). The fifth aliquot was diluted with extender containing 2.5percent DMSO at 37 as well as at 4C (T5). The final concentration of spermatozoa was 50×106/ml in all the treatment groups. Semen was cooled from 37 to 4C in 2 h and equilibration was done at 4 C for 4 h. Later on, packing of cooled semen was undertaken in 0.54 ml French straws and frozen in a programmable cell freezer. RESULTS: At post thawing, treatment groups T1 and T2 yielded significant (P < 0.05) outcome for CASA parameters, longevity, acrosomal integrity, plasma membrane integrity, mitochondrial transmembrane potential and DNA integrity. CONCLUSION: We concluded that by decreasing glycerol concentration (4.5 percent) and combining it with DMSO (1.5 percent) at 37C (T2) in tris-citric acid based extender provided similar results to those observed when glycerol (6 percent) alone is used at 37C (T1) for improving the post-thaw quality of buffalo bull spermatozoa.