• animal semen
• Carnosine
• kinetic parameters
• l-Histidine
• Taurine

In this Doctoral Thesis the natural presence of Carnosine and L-Histidine in seminal plasma and spermatozoa of boar, donkey and stallion was proved.
These molecules showed a positive effect, in nature, on some seminal parameters.
The artificial addition to BTS extender in boar fresh semen of these molecules demonstrated that Carnosine affect positively the kinetic parameters and the same happens with Taurine, instead l-Histidine demonstrated a negative effects.
Their additions to thawing extender in frozen-thawed boar spermatozoa showed that Taurine increased the sperm functionality, instead Carnosine could induce pro-oxidative process in high concentration with consequent negative effect on spermatozoa although no significant differences were showed in motility, viability or chromatin condensation.
In conclusion, Carnosine and Taurine appears to play an important role in the sperm antioxidant defence strategy.
Indeed addition of Carnosine to the extender in boar fresh semen and of Taurine to thawing extender in frozen boar semen could be of significant benefit in improving the function and fertilizing ability of boar spermatozoa.