Influência da estação sobre as proteínas do plasma seminal na raça Tabapuã (Bos taurus indicus)

Abstract

The objective of the present study was to evaluate the season influence on the seminal plasma proteins in Tabapua breed bulls raised on field. The study was conducted from June to August (winter) 2006 and from December to February (summer) 2007 in a farm in the country of Presidente Prudente, SP, Brazil. Eleven bulls were submitted to six semen collects throught eletroejaculation in each season at 14 days intervals. Samples of semen were centrifuged at 1500 g/15 min and conditioned in criotubes and stored at -20oC until further processing. The Proteins were extracted (Laemilli, 1970) and quantified (Bradford, 1976) and the electrophoresis was performed; the gels were fixed, and stained in the same solution with 2% of Coomassie Blue R250. In five bulls, the absence high molecular weight (HMW 55 KDa, 66 KDa and 80 KDa) proteins was verified in the summer and other one which is supposed to be of low fertility (LF 44 KDa), verified in two bulls in winter. Seven bulls showed presence of HMW (55KDa) in the winter. In three bulls HMW (55 KDa) and in one animal HMW (66 KDa and 80 KDa) proteins were present with a satisfactory semen condition. Eight bulls showed presence of HMW proteins (125 KDa) in winter and summer. In conclusion, the winter period presented an improvement in the qualitative aspects of the semen. A seasonal effect between the presence of the specific proteins and the increase of the semen quality was observed.