EFFECT OF SYNTHETIC AND NATURAL ANTIOXIDANTS ON PRESERVATION AND FERTILITY OF RAM SPERMATOZOA

The current experiment was conducted to evaluate the effect of synthetic (vitamin E and glutathione) and natural (rosemary extract) antioxidants on ram sperm characteristics during three sessions (equilibration, frozen-thawing and fertility rate) using three mature Rahmani rams. Semen collection was performed twice weekly for four weeks by artificial vagina.
In equilibration and frozen-thawing sessions ejaculates were pooled split into four aliquots. The1stpart(P1) was controlwithout any antioxidant type.However,thevitamin E, glutathione and rosemary extract were added in each concentration 50 mg/ml of each to another three portions P2, P3 and P4, respectively. After that, straws were stored at 5 ℃ as equilibration period and frozen at -196 ℃ by using liquid nitrogen. Sperm characteristics as progressive motility,viability, normality of spermatozoa,integrity of acrosome and concentration of lipid peroxidation (by assay malondialdehyde acid, MDA) were investigated post-equilibration and in frozen-thawing conditions. In addition, conception rate was calculated within frozenthawing of P1, P2, P3 and P4 using forty ewes as well as in reproductive and productive performance. The results showed that sperm characteristics and sperm recovery rate were higher (P<0.05), but concentration of MDA was lower (P<0.05) in P2, P3 and P4 than P1 extenders post-equilibration and thawing conditions. Furthermore, there were different values among P1, P2, P3 and P4 extenders in conception rate of ewes; it achieved 37.50, 53.33, 53.33 and 57.14%, respectively. The findings of this study indicated that extenders supplemented with rosemary extract (as natural antioxidant) could be ameliorated sperm characteristics, pregnancy rate and reduced oxidative stress parameters corresponding to
vitaminEand glutathione(as synthetic antioxidant)during cryopreservationofram spermatozoa.
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