RESUMO
The supplementation of cryopreservation media with antioxidants improves the post-thaw quality and fertilizing ability of spermatozoa. To maximize the fertility of frozen-thawed buck spermatozoa, further research is required to overcome obstacles that have yielded controversial results and standardize protocols. In the present work, the effect of adding fumaric acid (a well-described antioxidant) to a soy lecithin semen extender on certain quality parameters of spermatozoa following freezing and thawing was examined for the first time. Five sexually mature Skopelos bucks were used, and ejaculates were collected with an artificial vagina. The semen samples (98 samples, five replicates) were diluted (400 × 106 spermatozoa/mL) with OviXcell®, supplemented with fumaric acid (0 mM, 2.15 mM, 10 mM or 30 mM), equilibrated (5 °C; 3 h), packed (0.5 mL straws), frozen and stored (-196 °C) until further processing. After thawing, the spermatozoa total and progressive motility (CASA), viability (eosin-nigrosin), membrane functional integrity (HOST), acrosome integrity (SpermBlue®) and mitochondrial function (Rhodamine-123/SYBR-14/PI) were evaluated. Statistical analysis was performed with one-way ANOVA, followed by Duncan's test; significance was set at 0.05. The addition of 2.15 mM fumaric acid improved (p < 0.05) spermatozoa viability, membrane functional integrity, acrosome integrity and mitochondrial function compared to all other concentrations. The addition of 30 mM fumaric acid decreased (p < 0.05) spermatozoa viability and mitochondrial function compared to all other concentrations. These results indicate a beneficial effect of a 2.15 mM fumaric acid addition to a soy lecithin extender on post-thaw buck spermatozoa quality. Further research is required to evaluate the in vivo fertility of frozen-thawed buck spermatozoa treated with fumaric acid, as well as to elucidate the mechanism of action of fumaric acid in spermatozoa.
RESUMO
This study aimed at investigating the in vitro effects of zearalenone (zen) and alpha-zearalenol (alpha-zen) on motility and nuclear chromatin integrity (NCI) of boar spermatozoa. Mycotoxins were tested, at levels ranging from 10 to 30 microg ml(-1) of diluted semen. Four boars were used for semen collection (eight replicates per boar, four per mycotoxin). After the addition of zen or alpha-zen, semen samples were incubated for 4 h at 38.5 degrees C, 5% CO(2) and 96% humidified air. Motility and NCI were assessed at 0 and 4 h of incubation. No significant differences were noticed in motility among the experimental groups (P > 0.05) for all tested boars. Chromatin instability was significantly higher (P < 0.05) in spermatozoa of only one boar treated with zen and alpha-zen independently of the dose. In conclusion, under our experimental conditions, zen and alpha-zen did not affect the motility of boar sperm, whereas the effects of these toxins on sperm NCI were individual-dependent.
