Abstract
During the freezing process of semen, due to the generating of significant amounts of free radicals, the quality of sperm changes. Epigallocatechin-3-gallate (EGCG) is a green tea catechin, which in this study was applied to investigate its effect on the quality of bulls' sperm. We collected semen samples with an artificial vagina from 12 Simmental bulls to evaluate the effect of EGCG (10.00 and 20.00 µmol) in two cryopreserving methods on the quality parameters of semen. We designed six groups including two control groups (method one and two) and four treatments (EGCG 10.00 µmol + method one; EGCG 20.00 µmol + method one; EGCG 10.00 µmol + method two; EGCG 20.00 µmol + method two). The 20.00 µmol EGCG and a method two significantly affected the amending oxidative conditions as well as an increase in total antioxidant capacity and a decrease in malondialdehyde. The effect of EGCG in both concentrations was more on method two. The desired impact on sperm motility, viability, inhibition of lipid peroxidation and sperm DNA damage was observed in EGCG groups compared to control groups. Among the two methods, the method two had fewer adverse effects on the plasma membrane, motility parameters, viability and DNA of sperm. The EGCG in the semen extender yielded a favorable impact on thawed sperm. This effect was prompted in combination with the method two.