The Effect of Different Levels of Amino Acid Cysteine on Sperm Quality and Total Antioxidant Capacity of Seminal Plasma in Arabi Ram

Inroduction & Objective: During the semen storage, oxidative damages by oxidation are the major causes of decrease in sperm quality.The aim of this study was toevaluate the effect of different levels of cysteine supplemented into the diluent on semen characteristics of Arabi ram in liquid condition under 5 . Semen sampleswere collected weekly from 10 Arabi rams for 8 weeks and mixed. After dilution, samples were divided into 5 parts and received the levels of cysteine (5, 10, 15 and 20 mmol).During the storage (1, 12, 24, 36 and 48 h), semen quality parameters were evaluated. In all times of semen storage,sperm membrane integrity rate in cysteine treatments was improved(P<0.05). 24 and 36 h after semen storage, spermatozoa viability in 5, 10 and 15 mmol of cysteine was increased (P<0.05). In 36 h and 48 h, 5 and 10 mmol of cysteine reduced the spermatozoa defect rate(P<0.05). In 48 h of storage, progressive motility and viability rates of spermatozoa in 5-15 mmol of cysteine increased(P<0.05). The highest total antioxidant capacity of semenal plasma for times 1 and 24 h of semen storage was observed in 15 and 20 mmol of cysteine (P<0.05). In conclusion, with increasing the storage period of Arabi ram semen, the lower levels of cysteine (lower than 15mM), improved the most of spermatozoaqualitycharacteristics. But, the total antioxidant capacity of seminal plasma was increased in higher levels of cysteine (15 and 20 mmol).