Importance of antioxidant addition in cryopreserved ram sperm

Semen cryopreservation is reproductive biotechnology that allows the storage of genetic resources for long periods at low temperatures. This process reduces the levels of endogenous smen antioxidants and it should be added before freezing in an attempt to minimize the production of reactive oxygen species, which are physiologically involved in maintaining of fertilizing capacity and responsible for the sperm capacitation, and them are normally produced by the energy metabolism of spermatozoa or due to exogenous addition. Antioxidants are important in reducing the damage caused by the cryopreservation, preserving the physical and chemical integrity of sperm cells. The aim of this literature review was to identify the main antioxidant classifications and to verify current methodologies on the addition of antioxidants to cryopreserved semen of sheep, highlighting the importance of the use in reducing lipoperoxidation. The different classes of antioxidants provide satisfactory results for post-thawed sperm parameters of ram when used at optimum concentrations, in addition to the analysis performed with previously unavailable technological tools. It is concluded that research with antioxidants in sheep semen has been carried out for a long time and remains until the present day, with a perspective of innovation by using previously untested substrates.