Uso de antioxidantes para elevação da qualidade do sêmen criopreservado de búfalos (Bubalus bubalis)

Abstract

The buffalo semen suffers with the freezing process, which leads to oxidative stress. The aim of the research was to develop mechanism of semen cryopreservation, based on the addition of antioxidants substances, in order to decrease sperm mortality and cellular damages, to shift buffalo semen quality after thawing and to disseminate superior genetic material. Five Murrah buffalo bulls were used (4-8 years) and semen collections were performed with artificial vagina method. Before freezing, ejaculates were divided into four treatments: Control Group – frozen semen with TES-TRIS; Ascorbic Acid Group – TES-TRIS added with ascorbic acid (2.5 mM); Pentoxifylline Group - TES-TRIS with pentoxifylline (3.5 mM); and Ascorbic Acid + Pentoxifylline Group - TES-TRIS with ascorbic acid (2.5 mM) and pentoxifylline (3.5 mM). Raw semen (Pre-Freezing Phase) was analyzed to volume, pH, color, aspect, mass activity, spermatic concentration, spermatic motility, vigor, plasma membrane integrity and spermatic morphology. After thawing (Post-Thawing Phase) and after the thermoresistance test (Post- TTR Phase), analyses of spermatic motility, vigor, plasma membrane integrity and spermatic morphology were realized. Results were analyzed by ANOVA, Tukey Test and correlations were calculated by Pearson Test, using for that BioEstat 5.0 and SPSS 12 statistical softwares. The level of significance adopted was 5%. Significant statistical difference were observed in relation to progressive spermatic motility in Post-TTR Phase (Control: 15.1 ± 15.3%; Ascorbic Acid: 25.6 ± 16.3%; Pentoxifylline: 23.3 ± 14.6 and Ascorbic Acid + Pentoxifylline: 28.6 ± 16.2%; P<0.05). The other spermatic characteristics showed no significant statistical difference between treatments (P>0.05). Thus, the use of ascorbic acid, isolate or associated to pentoxifylline, in the buffalo semen may increase the potential fertility and the dissemination of superior genetic material.