Seminal Plasma Proteome: Promising Biomarkers for Bull Fertility

The seminal plasma is a mixture of secretions from the testis, epididymis and male accessory sex glands. A number of seminal plasma proteins are associated with male fertility but most of these have not been studied in detail till now. Recently, proteomics has been used to show the differences in proteins profile in seminal plasma from high and low fertility bulls. For example, osteopontin, phospholipase A2, P25b, acidic seminal fluid proteins, a-L-fucosidase and cathepsin D are positively correlated with fertility of bulls and may act as useful fertility marker (s), while lipocalin-type prostaglandin D synthase, spermadhesin Z13, clusterin and ubiquitin are negatively correlated with fertility in bulls. Bovine seminal plasma proteins in seminal plasma act like a double-edged sword and showed a quadratic association with bull fertility. The physiological roles of the metalloproteinase-2 (TIMP-2), ecto-ADP-ribosyltransferase 5, nuclobindin, Niemann-Pick C2 and epididymal sperm-binding protein 1 and their relationship to bull fertility need further studies. This review summarizes the physiological functions of proteins of seminal plasma and their relation to bull fertility.