[Relation between the denaturation changes in the diluents and the freezability of bull spermatozoa]

Studied were the changes taking place in the proteins of diluted and frozen semen of bulls following heat treatment. Studied was also the effect of heat-treated diluents on some of the qualitative indices of bull semen at cryo-conservation. It was found that at the dilution of semen with extenders with or without heat treatment there set in various changes in the percent distribution of proteins. Most strongly expressed were the changes in proteins when the gkh22l diluent was used. They were associated with the various degree of dilution with different extenders. The heat treatment of gkh22l improved the heat resistance of spermatozoa after thawing; the Nagaze Niva diluent was shown to slightly deteriorate this index. The cumulation of more proteins in the region of the 2nd fraction following the heat treatment of gkh22l at 70 degrees C for 60 min and dilution of 1+6 rendered more favourable conditions for the spermatozoa at freezing. The drop of the proteins in the region of the 1st fraction at dilution of 1+2 with Nagaze Niva led to the drop of its protective properties.