Effects of seminal plasma on inhibition/reversal of capacitation-like changes and fertility of cryopreserved boar sperm

Abstract

This project aims to determine whether cryopreservation causes capacitation-like changes and also if addition/maintenance of boar seminal plasma before or after thawing reduces these effects. For this, ejaculates from twelve boars will be collected. After analyses of raw semen, it will be diluted before centrifugation. After this, semen pellet will be divided in two treatments: Control (CON) - suspended with extender for cryopreservation and (PAC) - suspended with extender for cryopreservation within 10 % (v/v) of seminal plasma. Extended semen will be loaded in 0.5 mL straws and then subjected to cryopreservation. Ten straws from each batch will be thawed from group PAC and ten from CON. Forty five mL of Prolimax® extender will be added on CON and PAC groups in order to obtain fifty mL of insemination dose within 60x106sptz/mL. From the same batch, another ten straws from CON will be thawed and extended with Prolimax®, within 10 % (v/v) of seminal plasma giving rise to the third treatment, group PDC. After seminal plasma addition, samples will be maintained in water bath (37ºC) until 120 minutes. Experimental groups will be analyzed at time 0 and 120 min. The assessment of each sample will be determined by computer-assisted sperm analyzes of motility (CASA) and flow cytometry analyses of acrosome reaction, increased membrane fluidity, lipid peroxidation and degree of protein tyrosine phosphorylation in sperm surface. For fertility test, seventy five gilts will be inseminated with three treatments CON (n=25), PAC (n=25) e PDC (n=25). The variables will be submitted to analysis of variance (PROC GLM) and means will be compared by Tukey test. Fertility and birth rate will be analyzed by Chi-Square non-parametric test for P<0.05. (AU)