Antioxidant effect of Syzygium aromaticum extract on sperm quality in Arabi ram during semen storage in liquid condition

The lipid compositions of mammalian plasma membrane of spermatozoa are highly sensitive to oxidative stress due to the presence of high amounts of unsaturated fatty acids. If the production of active oxygen compounds is more than the antioxidant capacity of sperm to neutralize its effects, the sperm will undergo oxidative damage, which is characterized by the reduction of qualitative and viability parameters of spermatozoa. In recent years, research has been done on the antioxidant properties of some plants and their protective role for animal spermatozoa. So, the purpose of this research was to investigate the in vitro effect of Syzygium aromaticum extract on the spermatozoa qualitative parameters and preservation of sperm viability under the semen storage in liquid condition.

Semen collection was done from 8 Arabi rams weekly for 6 weeks and their semen was immediately mixed and after dilution, divided into 5 parts. The treatments included the addition of different levels of zero (control), 25, 50, 75 and 100 µg/ml of clove bud extract to the semen diluent. At zero, 24, 48, 72 and 96 hours after storage the semen samples at 5°C, the quality parameters of the spermatozoa included the motility, viability, plasma membrane integrity and morphological defect rates were evaluated.

At zero time, spermatozoa quality parameters were not affected by the treatments (P<0.05). In 24 hours, the percentage of motility, viability and plasma membrane integrity of spermatozoa in 100 µg/ml of Syzygium aromaticum extract decreased (P<0.05), and lower levels of extract were ineffective on the mentioned parameters of spermatozoa compared to the control. But, after the storage of samples up to 96 hours, 25 and 50 µg/ml of extract significantly improved the percentage of motility, viability and plasma membrane integrity of spermatozoa compared to the control (P<0.05). There was no significant difference in the percentage of spermatozoa morphological abnormalities among the treatments (P<0.05). 

In general, adding 25 µg/ml of Syzygium aromaticum extract to semen diluent of Arabian ram improved the motility, viability and plasma membrane integrity of spermatozoa as well as maintain their viability during the storage of semen under 5˚C.