Perfil das proteínas do sêmen de caprinos da raça Alpina Americana nas estações seca e chuvosa

Abstract

In Northeastern Brazil, the food lack on the low pluviometric index period is one of the factors that interfere on the goat reproduction, in spite of these animals be adapted to this region. The Aim of this study was to evaluating the effect of high (HPI) and low (LPI) pluviometric index on the proteins profile of goat semen of the American Alpine race raised on Camocim de São Félix, Pernambuco. It was realized semen collection by artificial vagina method during two years (2005, 2006). The semen samples were submitted to macroscopic (color, volume and appearance) and microscopic (progressive motility, vigor, concentration, morphology, and acrosome and DNA integrity) analyses and then divided into aliquots to realize the procedures: 1) freezing (0.5 mL), 2) protein dosages (1 mL) and 3) analysis of acrosome and DNA integrity (± 0.5 mL). The samples were packed in straws (0.25 mL), freezing in machine TK3000 (-0.25 °C/min, 25 °C to 5 °C, and - 20 °C/min of 5 °C to -120 °C) and stored in cryobiologic container (-196 C). After thawing (37 ° C, 30 seconds), the samples were evaluated to progressive motility (PM), vigor and acrosome and DNA integrity. The semen protein profile was conducted through the analysis of two-dimensional electrophoresis, after determination of total protein for standardization of the protein amount applied in gel electrophoresis. On the in natura semen, there was no significant difference (P>0.05) on the PM among animals and between LPI (79.82%) and HPI (81.25%) periods, as well as on sperm vigor on the LPI (4.17) and HPI (4.00) periods. However, it was observed higher(P<0.05) percentage of sperm with intact acrosome on semen collected on HPI (90.25%) than LPI (80.26%). After thawing, it was observed significant difference (P<0.05) on the PM of the samples obtained during the LPI (60.00%) and HPI (71.30%) periods, and no significant difference (P>0.05) on the cells with intact acrosome on the LPI (67.98%) and HPI (66.83%). In the protein samples extracted of in nature and thaw sperm membrane, 56 and 165 spots of proteins were identified with 25 to 103.0 kDa and 9.0 to 131.0 kDa, and with 3.36 to 9.74 and 3.37 to 8.80 pIs, respectively. On the evaluation of the seminal plasma proteins were detected 96 spots of protein, with 49 spots in the LPI period (15 to 97 kDa, 4.48 to 9.83 pI) and 47 spots in the HPI period (4 to 106 kDa and 3.00 to 8.96 pI). The periods HPI and LPI had 22 common spots of proteins, corresponding to 45.83% of similarity among spots analyzed. In the gel analysis of the thawed semen samples it was observed increase of protein spots number than in natura semen. It is suggested that groups of proteins of low molecular mass of seminal plasma membrane and the sperm of goats are responsible for sperm motility and the presence of a group of proteins on 14-15 kDa and 45kDa are responsible for the viability of the sperm cells in this experiment.