Proteins and Heparin Binding Proteins of Spermatozoa and Seminal Plasma in Beetal Bucks: Purification, Characterization and Role in In vivo Fertility

Background: The proteome analysis of seminal plasma and spermatozoa is of special relevance in livestock. Heparin binding proteins (HBPs) found in the seminal plasma of several mammals are shown to bind to sperm membrane and affect a series of events that contribute to normal fertility, such as sperm capacitation, formation of the oviduct reservoir and binding to the oocyte. Profiles of HBPs from seminal plasma and sperm membranes have been associated with sperm fertility. Although, HBPs present in the SP are described in several species, but little is known about HBPs in buck.Methods: Seminal plasma (SP) and sperm extracts (SE) of 13 bucks were subjected to heparin-sepharose affinity chromatography. Sperm extract, seminal plasma and purified HBPs and Non-HBPs were fractionated by SDS-PAGE. Total 78 females (6 per buck) were mated with 13 bucks. Bucks were divided into two groups, G-I (high fertile, 83.3-100% FR) and G-II (low fertile, 50-66.7% FR). Relationship between HBPs and fertility rate was observed.Result: SDS – PAGE of SP and SE resulted in resolution of 22 (10-240 kDa) and 21 (10-270 kDa) bands, respectively. Based on fertility rate 15 and 13 kDa proteins were absent in SP of higher number of GI-compared to G-II bucks. Fourteen bands ranging from 10 – 180 kDa and 10 – 150 kDa were separated from SP-NHBP and SP-HBP. SP-HBPs of 75, 35, 30, 28, 25 and 13 kDa were present in higher (28.6%, 42.5%, 26.2%, 40.5%, 14.3% and 36.2%) number of high fertile than low fertile bucks. NHBP and HBP purified from SE resolved into 11 bands ranging from 10 – 135 kDa and 10 – 120 kDa, respectively. SE-HBP of 53 kDa, 50/45 kDa and 25 kDa were present in higher percentage of high fertile than low fertile bucks.