The Effect of Storage on the Protein Electrophoretic Pattern in Bovine Serum

This study was aimed at the evaluation of the influence of storage under various conditions on the relative concentrations of major protein fractions and their proportion in bovine serum. Blood samples were taken from six dairy cattle of a low-land black spotted breed and its crossbreeds. The separated blood serum was fractioned into aliquots. One aliquot was analysed immediately after the separation without storage. The second aliquot was stored at 4 °C for 1 day, the remaining aliquots were kept frozen at -18 °C for 2, 7, and 21 days, and then analysed. Blood serum was analysed by agarose gel electrophoresis for the major protein fractions – albumin (%), alpha-globulins (%), beta-globulins (%), and gammaglobulins (%). Over time, the relative concentrations of albumin in bovine serum showed a tendency of significant decrease during the storage at -18 °C (p <0.001). An opposite trend was observed in the percentages of alpha-globulins and gammaglobulins with significant increase of values during the study period (p <0.05). In the relative concentrations of beta-globulins in the frozen serum samples, no significant variations were observed. The evaluation of the differences in serum protein fractions between samples without storage and samples stored at 4 °C showed a non-significantly decreased relative concentration of albumin and a significantly increased percentage of gammaglobulin fraction in the refrigerated samples (p <0.05). The presented results indicate that the temperature at which serum samples are stored, and the duration of the storage may affect the electrophoretic pattern of serum proteins.