%0 Journal Article %T Comparison of the Effect of Heterologous and Homologous Seminal Plasma on Motility and Chromatin Integrity of Stallion Spermatozoa Selected by Single Layer Centrifugation %A J. M. Morrell %A A. Johannisson %J Journal of Veterinary Medicine %D 2014 %R 10.1155/2014/325451 %X The effect on sperm motility and chromatin integrity of adding homologous or heterologous equine seminal plasma (SP) to fresh stallion spermatozoa selected by single layer centrifugation (SLC) was studied. No statistical difference in mean progressive motility was seen after adding SP at time 0£¿h, although there were differences for individual stallions. The proportion of spermatozoa with high velocity was increased compared to untreated SLC-selected spermatozoa ( ), with significant differences between individuals ( ). When the SLC samples were stored for 24£¿h before adding SP, a significant increase in mean progressive motility was seen for SLC + homologous SP ( ) and for SLC + heterologous SP ( ). Whether homologous SP or heterologous SP had a greater effect on progressive motility depended on the individual. Adding either type of SP caused a significant increase in chromatin damage compared to SLC after storage for 24£¿h (homologous SP, ; heterologous SP, ). These preliminary data showed that storage of SLC-spermatozoa mixed with SP should be avoided because of the risk of increased chromatin damage. If SP is to be added to take advantage of a transient increase in progressive motility for a particular individual stallion, different combinations of SP and spermatozoa should be tested first to optimize the effect. 1. Introduction The effect of seminal plasma (SP), which is the noncellular component of semen, on spermatozoa is the subject of much discussion. The amount of SP may be reduced when preparing semen doses for artificial insemination (AI) because cooled stallion spermatozoa survive better and show greater motility when the seminal plasma is diluted using semen extender [1]. Furthermore, it is common practice to remove most of the SP prior to freezing [2, 3]. However, components of SP have been identified as being beneficial to fertilization, such as the cysteine-rich secretory proteins (CRISP), which are considered to play important roles in sperm physiology, for example, by preventing premature capacitation (CRISP-1 D form), and in sperm-egg interaction, for example, CRISP-1 E form [4]. Moreover, nonprotein SP constituents such as cholesterol may protect the spermatozoa during in vitro storage [5]. Recently developed techniques for selecting robust spermatozoa for AI by colloid centrifugation [6, 7] remove all the seminal plasma from the spermatozoa, removing even the SP proteins coating the sperm surface [8]. It is not known what effect this removal has on either the spermatozoa themselves or on the mare¡¯s uterus, although stallion %U http://www.hindawi.com/journals/jvm/2014/325451/