SDS-polyacrylamide gel electrophoresis of buffalo bulls seminal plasma proteins and their relation with semen freezability

The objective of this study was to evaluate the protein profiles of seminal plasma in buffalo bulls and to
examine their correlation with semen characteristics. Semen of 10 buffalo bulls were collected by a bovine
artificial vagina. Semen characteristics (motility, morphology, viability and concentration) were recorded.
A part of the semen sample (1 ml) was diluted by tris-egg yolk-glycerol extender, packed in French straws
and was frozen in liquid nitrogen. The straws were later thawed and semen characteristics were compared
with those of the fresh semen.
Seminal plasma was harvested by centrifugation; treated with cold ethanol and then, underwent SDSpolyacrylamide
gel electrophoresis (PAGE). Twenty five protein bands were identified on the gel, of which
those of <35.5 kDa were prominent (72% of the bands). Of these protein fractions, 24.5 kDawas significantly
correlated with sperm progressive motility in fresh and viability in frozen-thawed semen while 45 kDa bands
were correlated with abnormal morphology in frozen-thawed semen; 55 kDa protein fractions were correlated
with sperm viability of fresh semen.
Progressive motility, viability and abnormal sperm morphology of frozen-thawed semen were highly
correlated with these parameters in the fresh semen.
In conclusion, seminal plasma protein fractions in buffalo bulls are similar to those reported in other
animal species and have some correlations with semen characteristics before and after freezing.