Comparative evaluation of seminal plasma proteins in Holsteiner and East Bulgarian horse breeds in relation to functional parameters of spermatozoa

Abstract

The present research was focused on the differentiation of specific proteins in the seminal plasma (SP) of two horse breeds - Holsteiner (n=4) and East Bulgarian (n=4) and their relation with indivi­dual or breed characteristics, kinematic parameters of spermatozoa and the sperm head area. After CASA analysis of 8 ejaculates, no statistical differences in the kinematic parameters of the sperms between the two horse breeds were found out with the exception of the sperm head area (P<0.05), which can be considered as a morphometric marker of breed affiliation. The values ​​for rapid sperm in East Bulgarian and Holsteiners were 28.1±0.2 μm2 and 19.9±0.3 μm2 respectively. The chromatographic analysis demonstrated specific quantitative and qualitative protein content of the individual chromatographic peaks (11 for Holsteiner and 15 for the Eastern Bulgarian breed), with similarity to the basic proteins. Three specific proteins with a molecular mass of 76 kDa, 21.6 kDa and 24.3 kDa, were differentiated by SDS PAGE in the Holsteiner breed, whereas in the Eastern Bulgarian horse breed they had a lower protein mass - 30.1 kDa and 14.2 kDa and 12.6 kDa. In conclusion, differences in the specific protein profile of Holsteiner and Eastern Bulgarian horse breeds are individually and naturally determined without significant effect on sperm kinematics. The sperm head area was a breed-specific difference.