DefinePK

Abstract

Typically, cryopreservation has detrimental effects on physical and morphometric properties of spermatozoa and, hence, on sperm fertilizing capacity. In the current investigation we evaluated the efficiency of supplementing ram semen diluent either with L-Ascorbic acid or ?-Tocopherol on ameliorating cryopreservation-induced oxidative stress. Ejaculates (n= 15) were collected from 5 adult Barki rams, 3 ejaculates each, by an artificial vagina during January, 2017. After evaluation, ejaculates of each collection session were pooled, diluted (1:10) with glycerolized Tris-citric acid egg yolk and were further split into 7 aliquots corresponding to the following groups: control (untreated), vitamin C (0.1, 0.2 or 0.3 mM) and vitamin E (0.1, 0.2 or 0.3 mM) (T0). Thereafter, all specimens were equilibrated for 5 hr at 4oC before being processed for cryopreservation. Post-thaw physical and morphological sperm properties were determined by CASA. The results showed that both low vitamin C (Vit-CLD) and high vitamin E (Vit-EHD) levels in preservation medium improved (P<0.05) post-thaw physical and morphological properties of spermatozoa, thus, they were considered the optimum levels of each individual supplement. Furthermore, specimens supplemented with Vit-E HD¬ recorded the highest (P<0.05) values of post-thaw motility, viability, normal spermatozoa and sperm functional integrity compared to both control and Vit-C LD supplemented groups. Contrariwise, the later groups recorded the highest (P<0.05) percent of secondary sperm abnormalities compared to that of Vit-E HD specimens.¬ These results elucidate that supplementing the diluent with 0.3 mM ?-Tocopherol is most appropriate to increase ram sperm cryosurvival in vitro, which would be beneficial for maximizing utilization of cryopreserved ram semen for AI and IVF schemes.