Effect of antioxidant and polyunsaturated fatty acid treatment on epididymal sperm samples from Bos taurus taurus bulls

Abstract

Sperm recovery from the cauda epididymis to ve used for criopreservation can be very advantageous, for example: in case of the unexpected death of a genetically highly valuable animal, for preserving endangered species, or when the collection of sperm by other means becomes impossible. On the other hand, the sperm, even when collected from the epididymis, is highly susceptible to the attack by reactive oxygen species (ROS) due to the high content of polyunsaturated fatty acids (PUFA) in its membrane, which, however, is fundamental to allow the sperm to fertilize the oocyte or to resist cold shock. Among the PUFA in the sperm, the decosaexanoic acid (DHA) appears to be the most important for fertility; but high concentrations of this PUFA diminishes the resistance of the cells against the oxidative stress. Furthermore, one of the reasons for decreased quality of cryopreserved sperm, is the oxidative stress. Therefore, treatments aiming to interfere in the oxidative chain reaction or in the lipid profile of the sperm or medium, may be importante to increase the quality of cryopreserved epididymal sperm. The objectives of this study was to study the interaction of the diluent supplemented with DHA (to improve freezability and to study a possible antioxidant effect) and an antioxidant (to protect against cryopreservation on its own and to possible negative effect of the DHA), in an factorial 2x2.