Immunoactive relaxin in boar seminal plasma and its correlation with sperm motility

Abstract

Relaxin in boar seminal plasma ( n = 43) was assayed by an homologous radioimmunoassay. The seminal plasma levels of relaxin averaged 1.1 ± 0.38 ng/ml (±s.e.). The relaxin concentrations in seminal plasma were correlated with sperm motility ( n = 32, r = 0.33, P < 0.05) and the transmembrane migration ratio ( n = 11, r = 0.81, P < 0.01) of boar spermatozoa. Relaxin levels in seminal plasma of Yorkshire ( n = 19), Landrace ( n = 5), Duroc ( n = 10), and Poland China ( n = 4) boars were 1.3 ± 0.07, 0.9 ± 0.13, 0.8 ± 0.13, and 0.7 ± 0.03 ng/ml (mean ± s.e.), respectively. Seminal plasma relaxin levels differed among these breeds ( P < 0.05). The results in this study indicate the presence of immunoactive relaxin in boar seminal plasma which shows high positive correlations with sperm motility of fresh semen.