Effects of Taurine on Sperm Characteristics during In vitro Storage of Boar Semen

The objective of this study was to investigate the anti-oxidative effects of taurine on sperm characteristics for in vitro storage of boar semen. Semen was randomly divided into 10 groups in conical tubes and treated with different concentrations of taurine (25-100 mM) with or without $250{\mu}M$ $H_2O_2$. The percentage of motile spermatozoa in taurine groups after 6 and 9 h were significantly higher at >94% and 87%, respectively, compared to the control group ($85.1{\pm}0.5$ and $72.4{\pm}0.3$, p<0.05). The sperm motility in taurine with $H_2O_2$ after 6 h incubation was slightly decreased compared to the taurine alone treatment, but after 9 and 12 h incubation % sperm motility dropped sharply in taurine with $H_2O_2$ ($75.3{\pm}0.3$ and $69.6{\pm}2.9$, p<0.05). For 3, 9 and 12 h incubation, sperm viability in the control was lower than in taurine groups, irrespective of taurine concentration. In eosin Y and nigrosin staining (ENS), the sperm survival rates (%) for 6 h incubation were significantly higher in 25 mM ($76.0{\pm}0.6$) and 50 mM taurine groups ($78.0{\pm}0.7$), respectively. Sperm survival rates for 9 and 12 h incubation were higher in taurine groups (${\geq}48%$ in 9 h and ${\geq}42%$ in 12 h) compared to controls ($43.0{\pm}2.1$ and $31.0{\pm}0.6$, respectively). In the hyoosmotic swelling test (HOST), sperm membrane integrity was similar to the results of sperm survival. These experiments indicate that supplementation of taurine to the semen extender can increase the sperm characteristics(motility, viability, survival and membrane integrity).