The objectives of this study were to evaluate the properties of sperm motility and morphology under induced oxidative stress, compare the antioxidant capacity of dithiothreitol (DTT) and glutathione (GSH) following the cryopreservation of Large White boar semen, investigate the ability of cryopreserved Large White boar semen to fertilize the matured gilts oocytes and compare the efficacy of DTT and GSH antioxidants in improving the oocyte fertilization by cryopreserved Large White boar semen. The semen was collected from three Large White boars (ten ejaculates per boar) and transported (37 °C) to the laboratory. Semen freezing extenders were supplemented with 5 mM DTT, 5 mM GSH and a combination of 2.5 mM DTT + 2.5 mM GSH. A liquid nitrogen vapor method was used to freeze boar semen. Gilts’ ovaries were collected from the local abattoir and transported (37 °C) to the laboratory. The slicing method was used to retrieve the oocytes from the ovaries. Fresh semen and frozen-thawed semen were used for in vitro fertilization (IVF). For frozen-thawed semen, four treatments (control, 5 mM DTT, 5 mM GSH, and a combination of 2.5 mM DTT + 2.5 mM GSH) were used during IVF in order to evaluate the fertilizing ability of the antioxidants. The supplementation of 5 µM DTT to H₂O₂-treated semen significantly improved progressive motility (PM) by 14.82%. A combination of 2.5 mM DTT + 2.5 mM GSH treatment reduced percentage of sperm total motility (TM) and rapid motility (RAP) following thawing (p < 0.05). Fresh semen and a combination of 2.5 mM DTT + 2.5 mM GSH treatment recorded a higher percentage of zygotes with polyspermy (p < 0.05). The control treatment numerically recorded a high percentage of zygotes with 1 PN, while the 5 mM DTT treatment recorded a high percentage of zygotes with 2 PN.

Interpretation of semen kinematic parameters remain as a point of discussion in predicting semen quality following processes like cryopreservation. During cryopreservation, oxidative stress remains a challenge in promoting post-thaw semen quality. Comparison of livestock semen exposed to oxidative stress, in vitro, highlight various aspects of sperm cell movement, like kinematics, to predict their qualities. Sperm cell kinematics includes the measurement of the distance between each head point for a given sperm cell during the acquisition period. Regrettably, the semen kinematic parameters are often reported with the limited interpretation. The apparent difficulty in interpreting these kinematic parameters can be interpreted clearly by looking at semen kinematics from various livestock species under similar conditions. Induced oxidative stressed conditions in cockerel, buck and boar semen present such an opportunity to investigate and interpret the significance of semen kinematic parameters and also check if any of the investigated livestock species can be used to set a threshold for semen quality. In this study, we are demonstrating that cockerel, buck and boar semen under induced oxidative stress present an opportunity to interpret the kinematic parameters associated with their semen quality. Such kinematic include curvilinear velocity, straight line velocity, average path velocities, linearity, straightness and wobble. All these kinematic parameters are readily available following computer aided sperm analyzer semen analysis. Three species, namely, buck boar and cockerel semen were collected. The semen was then exposed to oxidative stress inducing agent, hydrogen peroxide, for 3 h. The semen kinetic parameters were then compared. Our data seem to indicate that buck semen kinematics could be used as predictors of livestock semen quality under oxidative stress, at least for livestock species investigated.

The objective of this study was to assess the developmental competence and quality of embryos produced by Bonsmara, Nguni, and Boran cattle in a smallholder production environment using in vivo and in vitro techniques. This was a 3 x 2 factorial experiment in a completely ran-domized design, with breed (3 breeds) and embryo production tech-nique (2 methods) as factors. In vivo embryos were produced by ad-ministering hormones to experimental cows, while in vitro embryos were developed through ovum pickup and ovarian follicle aspiration. Embryo developmental competence was evaluated based on cell divi-sion stages, while embryo quality was assessed morphologically fol-lowing the standards of the International Embryo Transfer Society. The effects of breed and embryo production technique on developmental competence and quality were analysed using a linear fixed-effects model with the General Linear Models procedure in SAS software. Results showed that in vivo blastocyst development on day 8 was sig-nificantly (P< 0.05) higher in Bonsmara and Nguni cattle compared to Boran. However, no significant breed effects were observed on embryo developmental competence at any stage when using the in vitro tech-nique. Bonsmara cattle produced a significantly higher number of poor-quality (Grade III) embryos compared to Nguni and Boran. Addi-tionally, both flushing and ovum pickup methods yielded a significantly (P< 0.05) higher number of blastocysts and excellent-quality (Grade I) embryos compared to ovarian follicle aspiration. Overall, the study demonstrated that the in vivo method of embryo production is superior to the in vitro method in promoting blastocyst development in Bonsmara, Boran, and Nguni breeds.