Effects of ergothioneine supplementation on the quality of liquid-preserved and frozen-thawed boar semen.

This study examined the effects of ergothioneine (EGT) supplementation as an antioxidant on the quality of boar spermatozoa when using liquid and frozen preservation methods. In the first experiment, boar semen was preserved in an extender supplemented with 0, 50, 100 and 200 µM EGT, at 15 °C, part of the samples for one and another part for three weeks. In comparison with the control (without EGT), EGT supplementation at 100 µM significantly increased the percentage of total motility of spermatozoa that were preserved as a liquid both for one and three weeks (P < 0.05). EGT supplementation did not affect the quality of preserved spermatozoa, irrespective of the EGT concentration. In the second experiment, semen was frozen and thawed in the freezing extender supplemented with 0, 50, 100 and 200 µM EGT. In comparison with the control, the 100 µM EGT supplementation significantly increased the percentages of total and progressive motility of frozen-thawed spermatozoa (P < 0.05). EGT (100 µM) supplementation did not affect the viability, the plasma membrane integrity, or the acrosomal integrity of frozen-thawed spermatozoa. These findings indicate that supplementing extenders with 100 µM EGT may improve the motility of boar sperm in both liquid and freezing preservation methods.

Effects of curcumin supplementation on quality of porcine spermatozoa irradiated with ultraviolet-C at 228 nm during liquid preservation.

It is important to prevent microbial contamination during liquid preservation of semen in pigs. We examined the effects of curcumin supplementation on the quality of porcine spermatozoa irradiated with ultraviolet-C (UV-C) at 228 nm. UV-C is used to disinfect gases and solid surfaces. In the first experiment, porcine semen was preserved with 0, 10, 25, 50 or 100 µM curcumin under UV-C irradiation at 228 nm for 7 days at 15°C. The irradiation did not affect the motility and viability of preserved spermatozoa but decreased the percentage of plasma membrane integrity of spermatozoa. Curcumin supplementation at 25 µM significantly improved the plasma membrane and acrosome integrity of irradiated spermatozoa compared with spermatozoa preserved without curcumin (p < .05). In the second experiment, semen was preserved with or without 25 µM curcumin with UV-C irradiation at 228 or 260 nm for 3 days at 15°C. Curcumin supplementation increased the percentages of total motility, sperm viability and plasma membrane integrity of preserved spermatozoa at both irradiation wavelengths (p < .05). All quality parameters of 260 nm irradiated spermatozoa decreased compared to those of the other groups, irrespective of curcumin supplementation. The collective findings indicate that porcine spermatozoa can retain their viability even after continuous long-duration irradiation with 228 nm UV-C. Curcumin supplementation improves the quality of UV-C irradiated spermatozoa during semen preservation.

Effects of Tris (hydroxymethyl) aminomethane on the quality of frozen-thawed boar spermatozoa.

Tris (hydroxymethyl) aminomethane (Tris) has been used as a pH regulator for buffering the pH of dilution extenders for boar semen, such as the Modena extender. The purpose of the present study was to assess the effects of Tris supplementation at different concentrations (0, 8, 24 and 72 µM) into the freezing extender on the quality and fertilising capacity of frozen-thawed boar spermatozoa. The results showed that the supplementation of 24 µM of Tris gave significantly higher percentages of sperm viability and plasma membrane integrity than those of the control group at any time point of assessment (0 h and 3 h post-thawing) (P < 0.05). However, there were no significant differences in the acrosome integrity parameter among the groups. Higher percentages of sperm motility were observed in the spermatozoa cryopreserved with 24 µM of Tris compared to the control groups when the samples were analysed 0 h after thawing (P < 0.05). However, an increase of the Tris concentration to 72 µM did not enhance the sperm motility parameters. The total numbers of fertilised oocytes and blastocysts obtained with spermatozoa frozen with 24 µM Tris were significantly higher than those of the control group without Tris (P < 0.05). In conclusion, the supplementation of 24 µM Tris into the freezing extender contributes to a better boar sperm quality and fertilising capacity after the process of freezing and thawing.

Astaxanthin present in the maturation medium reduces negative effects of heat shock on the developmental competence of porcine oocytes.

Astaxanthin, one of the most common carotenoids, elicits antioxidant effects on cellular viability and embryonic development. This study was conducted to investigate the effects of astaxanthin on maturation, fertilization and development of porcine oocytes matured in vitro under heat stress conditions, and then fertilized and cultured under standard conditions. Porcine oocytes were cultured in maturation medium supplemented with different concentrations of astaxanthin (0, 0.25, 0.5 or 1 ppm) for 46 h at either 38.5 or 41 °C. In comparison to oocytes cultured at 38.5 °C, the exposure of porcine oocytes to 41.0 °C during in vitro maturation (IVM) significantly inhibited maturation and development of fertilized oocytes to the blastocyst stage. Supplementation of maturation medium with astaxanthin (0.5 ppm) significantly improved oocyte maturation, fertilization and development to the blastocysts stage in both oocyte groups. However, the total cell number and apoptosis index of blastocysts did not differ among groups. Moreover, astaxanthin (0.5 ppm) significantly increased the rate of oocytes that reached metaphase II and decreased proportion of apoptotic oocytes exposed to H2O2 (1.0mM) during IVM. In summary, we demonstrated that supplementation of maturation medium with astaxanthin (0.5 ppm) exerted antioxidative effects and improved the ability of maturation, fertilization, and development of porcine oocytes exposed to heat stress.