Motility of ram spermatozoa during storage in a chemically-defined diluent containing antioxidants

The effects of five antioxidants—Vitamin E (VE), butylated hydroxyanisole (BHA), n-propyl gallate (n-PG), deferoxamine mesylate (Desferal) and catalase (EC 1 · 11 · 1 · 6)—on the maintenance of motility of ram spermatozoa in a chemically-defined ram semen diluent (RSD-1) have been evaluated. VE, n-PG and Desferal inhibited spermatozoal motility. The relative inhibition (i.e., ratio of change in % motility over 24 h between the treatment group and the corresponding control) at equimolar concentrations (100 μM) of Desferal, VE and n-PG were 1.6, 1.8 and 3.6 respectively. BHA had no effect at 10 μM but at lower concentrations, gave a slight improvement in motility in freshly diluted spermatozoal samples and in those stored for 1 day at 15°C. The addition of catalase to RSD-1 was also ineffective in improving the motility of spermatozoa. The lack of beneficial effects of the tested antioxidants suggests that RSD-1 itself may destroy reactive oxygen species and the antioxidant activity of RSD-1 components requires further study.