The effect of adding different levels of zinc sulfate on Ghezel ram sperm function during the freeze-thawing process in out of breeding season

The purpose of this study was to compare the effect of different levels of zinc sulfate on improving the quality of ram semen during freeze-thawing process outside of the reproductive season. Semen samples were collected from five Ghezel ram twice a week using the artificial vagina. Sperm samples were assigned to four treatment groups including: control, 17.5, 35 and 52.5 μm zinc sulfate, and then the freezing process was performed. After thawing motility, morphology and malondialdehyde levels of sperm were studied. Total and progressive motility of sperm containing the 17.5 µmol/ml zinc sulfate were significantly higher than control group (P <0.05). There was a significant difference in sperm morphology in the group receiving 52.5 μmol of zinc sulfate compared to the control group, which caused 52.5% increase in abnormal sperm (P <0.05). Adding 17.5 μmol of zinc sulfate increased unsignificantly the viability of sperms compared to the control group, but adding 35 and 52.5 μmol decreased significantly (P <0.05). The level of malondialdehyde production in the 35 µmol was lower than the other treatment groups and the control group and there was a significant difference between the groups 17.5 and 35 in comparison with the control group (P <0.05). Therefore, it can be concluded that the use of 17.5 and 35 µmol Zinc sulfate in Ghezel ram diluent semen improves some of the parameters of the sperm after the freeze-thawing process.