Desenvolvimento reprodutivo e análise das proteínas do plasma seminal com afinidade à heparina, em tourinhos Gir selecionados para a produção de leite

Abstract

The study identified precocious (PREC) and non-precocious (NPREC) Gyr young bulls according to age at puberty, evaluated differences in their development and described the concentration of seminal plasma proteins heparin binding proteins (HBPs), associating them with reproductive parameters. Live weight and scrotal circumference (SC) were measured together with the collection and evaluation of semen of 16 animals from 13 to 23 months. Seminal plasma was collected in 40 mM TRIS buffer and subjected to heparin affinity chromatography. Parameters were compared between the groups and regression models were adjusted according to age. PREC animals were younger at puberty and sexual maturity, lighter in pre-puberty and had increased motility (MOT) and concentration (CONC) earlier than NPREC. Eight peaks (P1 - P8) were observed in the heparin affinity chromatograms. P1 represented proteins without affinity and the other peaks were eluted at six different concentrations of NaCl (0.09 M, 0.18 M, 0.3 M, 0.45 M, 0.6 M and 1.5 M). Except P1 and P2, all peaks increased from 18 (PREC) and 19 (NPREC) months. HBPs concentrations differed between groups at puberty. There were correlations between the peaks and reproductive parameters, especially P5, P6 and P7. P7 showed positive correlations with SC, MOT and CONC, inverse correlation with the major sperm defects and was the only associated with vigor. Differences in reproductive development of PREC and NPREC animals showed that selection for sexual precocity is indicated for reproductive efficiency improvement. P7 is an important marker of sperm function in Gyr bulls