Effect of glutathione on viability and acrosomal integrity of bovine spermatozoa during graded cryopreservation

The present study was aimed to evaluate the effect of Glutathione, an anti-oxidant, on the acrosomal integrity bovine spermatozoa by means of Trypan Blue-Neutral Red- Giemsa Staining at different stages of semen preservation (after dilution, pre-freeze) and post thaw. The semen was primarly examined for standard samples. Samples (N=24) of more than 70% progressively motile spermatozo with concentration of >600 million spermatozoa/ml was used for cryopreservation. The extension of fresh semen was done in a Glycerolated Egg Yolk Tris (GEYT) Extender upto 80 million sperm /ml. The various concentrations of Glutathione were added in diluted semen like 0.0 mM (Control), 0.5 mM (T1) & 1.0 mM (T2). The semen was cryopreserved in French Mini Straw using liquid nitrogen vapour as per standard protocol for patticular time interval (lowering of temperature from 4°C to −10°C @ 5°C/min, −10°C to −100°C @ 40°C/min, −100 to −140°C @ 20°C/min). The acrosomal membrane integrity of spermatozoa was evaluated after staining with Trypan Blue –Neutral red-Giemsa stain at given time and temperature ratio. The viability of spermatozoa with intact acrosome at post-thaw (370C for 45 sec) was significantly higher (P<0.05) in the treatment groups (T1) & (T2) and it was 54.43±0.65, 67.58±0.44 & 61.69±0.55 in control, T1 (0.5 mM Glutathione) and T2 (1.0 mM Glutathione) groups respectively. Furtherly, with in two treatments a significant difference was aslo seen (P<0.05) and it was higher in treatment group 1 (T1). Comparison (unpaired‘t’ test) between the bulls for control and treatment groups did not revealed any significant difference.