Effects of different extenders and additives on liquid storage of Awassi ram semen

Abstract

The aim of this study was to evaluate the effects of different extenders and additives on ram semen during liquid storage and todemonstrate the role of oxidative stress parameters on this process. In the present study, ejaculates taken by artificial vagina twice a weekfrom 4 rams during the breeding season were used. They were mixed and used if motility and viability were above 70% and there wasa 95% intact acrosome. The semen specimens were diluted by Tris-citrate-glucose (TRIS), Tris-TES (TEST), HEPES-buffered Tyrodelactate (TL-HEPES), and Dulbecco’s phosphate-buffered saline (PBS) extenders supplemented with different additives [centrifuged eggyolk, Equex-STM, bovine serum albumin (BSA), and ethylenediaminetetraacetic acid (EDTA)]. The specimens were stored at 4 °C forup to 96 h and evaluated for motility, membrane integrity, acrosome integrity, mitochondrial membrane potential (MMP), and oxidativestress parameters. At the end of the 96-h storage, the highest sperm motility was 64.2 ± 3.7% (P < 0.05) and significant loss of spermmotility and membrane integrity were not detected in extender TEST-3, but the MMP rate significantly declined. Acrosome integritywas not affected by storage time or extender types. BSA and EDTA decreased lipid peroxidation (LPO) and total oxidant status (TOS),but did not positively affect motility or membrane integrity. As a result, TRIS, TEST, and TL-HEPES-3 were observed to provide betterprotection for ram semen during liquid storage at 4 °C than other extenders. The role of oxidative stress and MMP are considerable inliquid storage.