No abstract

Cryopreservation of boar semen is still considered suboptimal due to the low fertility when compared with fresh semen. This study was performed to evaluate the effects of green tea (Camellia sinensis) supplementation of the freezing extender at different concentration (0, 2.5%, 5%, 10%) and also to determine the influence of increasing holding time from 2 to 24 h at 15 °C. Seventeen ejaculates from nine boars were used to make pools of three of them and then cryopreserved. Sperm motility, viability, acrosome integrity, membrane functionality (HOST) and capacitation status were determined before freezing and at 0, 30, 60, 90 and 120 min after thawing. Lipid peroxidation was evaluated just after thawing. The main findings emerging from this study were the following: (i) no improvement in quality of thawed spermatozoa with addition of tea to the freezing extender, (ii) no improvement in quality of thawed spermatozoa with prolonged holding time, (iii) lower peroxidation rate in presence of tea 5% and (iv) a decrease in the number of uncapacited viable spermatozoa with any tea supplementation. We conclude that amplification of holding time in semen cryopreservation process does not vary results, facilitating freezing protocol. Tea supplementation reduces lipoxidation but did not improve quality parameters.

Changes in the genital mucus around the oestrus are used by different diagnostic methods to determine optimal fertilisation time. In the current study, the authors evaluated the different arborisation patterns found in vestibular mucus, and also established its relationship with vestibular resistance changes during oestrus. Thirty multiparous sows were checked by transrectal ultrasonography to determine ovulation time every 12 hours. Vestibular resistance was measured with a commercial resistance probe, and vestibular mucus ferning was also evaluated every 12 hours during the oestrus. Significant changes (P < 0.05) in vestibular resistance were detected, registering high variation among individuals. Maximum resistance data was reached between 12 and 24 hours after ovulation time in 83 per cent of the sows. Crystallisation samples were classified into three different patterns according to the fern-like crystal degree. Arborisation peak occurred from 48 to 36 hours before the moment of ovulation, when vestibular resistance values increased gradually. In the optimal insemination moment, vestibular resistance increased significantly (P < 0.05) and vestibular mucus showed a low crystallisation pattern (P < 0.05). Combining several methods to measure genital mucus changes may predict the ovulation time and the best insemination moment.