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Doctoral thesis, 2017

The role of bovine seminal plasma in fertility

Nongbua, Thanapol


Bovine seminal plasma (SP) is known to have an effect on spermatozoa and the female reproductive tract. The differences in fertility among individuals could be due to variations in SP composition and its effect on both spermatozoa and the inseminated female. Single Layer Centrifugation (SLC) has been shown to select the most robust spermatozoa from the ejaculate and can be used to separate spermatozoa from SP. The purpose of this thesis was to study the various effects of bovine SP. The thesis was divided into 4 studies: Study I was to determine the effects of SLC on post-thaw sperm quality. Study II investigated the effect of adding SP back to SP-free sperm samples. Study III investigated the effect of bovine SP on bovine endometrial epithelial cells (bEEC) in culture. Study IV determined the effect of season and SLC on sperm quality. Our results show that bull spermatozoa selected by SLC had a higher proportion with high mitochondrial membrane potential (MMP) and a higher superoxide production than controls. The SLC-selected samples had a higher proportion of spermatozoa with normal morphology and a lower proportion with bent tails than controls; they had better kinematics than controls. However, sperm viability and chromatin integrity were not different between treatments. Adding 5% bovine SP had a beneficial effect on sperm velocity. Moreover, there was a beneficial effect of adding 5% heterologous SP from high fertility bulls on sperm velocity but a deleterious effect on chromatin integrity. Total cell number and viability of bEEC after challenge with 1% SP from either high or low fertility bulls did not differ from controls. In contrast, challenge with 4% SP from high or low fertility bulls (300H or 300L) negatively affected bEEC cell number and viability. Challenge with 300L had a greater adverse effect than 300H. There were differences in semen characteristics and sperm morphology among seasons. However, sperm kinematics, viability, chromatin integrity and MMP were not different between seasons. In conclusion, these results indicated that SLC can be used to enhance bull sperm quality. Moreover, adding bovine SP prior to cryopreservation affected sperm quality depending on the proportion of SP and the fertility of the bull from which it came. Bovine SP had a negative effect on bEEC in both a dose-dependent and fertility–dependent manner. Season had a slight effect on sperm morphology. Further studies are needed to investigate the factors involved in the interaction between SP and spermatozoa or bEEC, such as differences in SP composition between low and high fertility bulls, and breed and age of bull, as well as their effects on fertility. Keywords: bovine SP, fertility, proportion of SP, Uterus cell, sperm quality, Climate, frozen semen


bovine seminal plasma, fertility, proportion of SP, uterus cell, sperm quality, frozen semen, climate

Published in

Acta Universitatis Agriculturae Sueciae
2017, number: 2017:70
ISBN: 978-91-7760-030-5, eISBN: 978-91-7760-031-2
Publisher: Department of Clinical Sciences, Swedish University of Agricultural Science

    UKÄ Subject classification

    Medical Bioscience
    Animal and Dairy Science
    Clinical Science

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