Investigation of the protective effects of different forms of selenium in freezing dog semen: Comparison of nanoparticle selenium and sodium selenite.

This study aimed to investigate the protective effects of nanoparticle selenium (SeNP) and sodium selenite (SS) on preventing oxidative stress during the freezing process of dog semen. A total of six dogs were used in the study. The ejaculate was collected from dogs three times at different times by massage method. A total of 18 ejaculates were used and each ejaculate was divided in five experimental groups. The experimental groups were designed to tris extender containing no antioxidants control, 1 µg/mL SeNP1, 2 µg/mL SeNP2, and 1 µg/mL SS1 and 2 µg/mL SS2. Extended semen were equilibrated for 1 h at 4°C, then frozen in liquid nitrogen vapour and stored in liquid nitrogen (~-196°C). After thawing, semen samples were evaluated in terms of CASA motility and kinematic parameters, spermatozoa plasma membrane integrity and viability (HE Test), spermatozoa morphology (SpermBlue) and DNA fragmentation (GoldCyto). Antioxidant enzyme activity (glutathione peroxidase; GPX, superoxide dismutase; SOD, catalase; CAT) and lipid peroxidation (malondialdehyde; MDA) were evaluated in frozen-thawed dog sperm. When the results were evaluated statistically, the progressive motility, VCL, and VAP kinematic parameters in the SeNP1 group were significantly higher than the control group after thawing (p < .05). The highest ratio of plasma membrane integrity and viable spermatozoa was observed in the SeNP1 group, but there was no statistical difference found between the groups (p > .05). Although the ratio of total morphological abnormality was observed to be lower in all groups to which different selenium forms were added, compared to the control group, no statistical difference was found. Spermatozoa tail abnormality was significantly lower in the SeNP1 group than in the control and SS2 group (p < .05). The lowest ratio of fragmented DNA was observed in the SeNP1 group, but there was no statistical difference was found between the groups (p > .05). Although there was no statistical difference between the groups in the evaluation of sperm antioxidant profile, the highest GPX, SOD and CAT values and the lowest lipid peroxidation values were obtained in the SeNP1 group. As a result, it was determined that 1 µg/mL dose of SeNP added to the tris-based extender in dog semen was beneficial on spermatological parameters, especially sperm kinematic properties and sperm morphology, and therefore nanoparticle selenium, a nanotechnology product, made a significant contribution to the freezing of dog semen.

Melatonin Administration Enhances Testicular Volume, Testicular Blood Flow, Semen Parameters and Antioxidant Status during the Non-Breeding Season in Bafra Rams.

Our objectives were to investigate the effects of exogenous melatonin on testicular volume (TV), testicular blood flow (TBF), and semen quality in Bafra rams during the non-breeding season. One group of rams (MEL, n = 5) received a 36 mg melatonin implant twice, with 30 days in between, while the other group (CON, n = 5) served as the control. TBF, TV, and semen quality parameters were determined at three-week intervals starting three weeks before until twelve weeks after the first melatonin implant. Testicular blood flow was determined in the supratesticular (STA) and marginal testicular artery (MA) using color Doppler ultrasound. Semen was collected and evaluated, and the total oxidative status (TOS) and total antioxidative status (TAS) was determined using an ELISA. The MEL group had increased (p < 0.05) TV between the sixth and twelfth week after the start of treatment. Overall, the MEL group had lower resistance and pulsatility indexes (p < 0.05) between the third and ninth week, although there was no difference (p > 0.05) between the two groups in most semen quality parameters. However, TAS concentrations increased (p < 0.05) in the MEL group compared with the CON. The results of this study show that exogenous melatonin in the non-breeding season significantly increased both TBF and TV in Bafra rams. Therefore, giving rams implants with 36 mg melatonin twice at least one month prior to the non-breeding season is expected to improve testicular size and function and reproductive capacity.