Effect of manganese on bovine sperm motility, viability, and lipid peroxidation in vitro

Manganese (Mn) is a chain-breaking antioxidant in biological systems. The objective of the present study was to determine the optimal dose of Mn to reverse free radical-mediated oxidative damage on motility, viability, and lipid peroxidation (LPO) of sperm from five bulls (local crossbred cattle). Fresh semen was suspended in 2.9% sodium citrate, divided into equal fractions, and subjected to Mn treatment (0, 60, 100, or 200 μM) in the presence or absence of an oxidative stress inducer (ferrous ascorbate, FeAA; comprised of 150 μM FeSO4 and 750 μM ascorbic acid). All sperm suspensions were incubated (37°C) for 2 h. Treatment with FeAA decreased motility and viability but increased lipid peroxidation. All doses of Mn increased motility and viability but decreased LPO; however, 60 μM Mn was most effective. For sperm motility, viability, and LPO level, there were significant main effects of bull, treatment, and interval, as well as their interactions. In conclusion, Mn reduced the oxidative stress (LPO) caused by FeAA and improved sperm motility and viability under in vitro conditions as well as under induced oxidative stress.