EFFICIENCY OF AMIDES AS CRYOPROTECTORS IN THE COMPOSITION OF PROTECTIVE ENVIRONMENTS FOR BULLS SPERM CRYOCONSERVATION

Abstract

The article highlights the results of research on the effectiveness of the introduction of cryoprotectants of the amide group – dimethylformamide (DMF), dimethylacetamide (DMAC) into the cryoprotective media for bull sperm and to determine their effect on the main physiological characteristics of germ cells. Materials and methods. Immediately after obtaining sperm, it was diluted with medium No. 1 containing 5.6% glycerol and 1.4% DMF (experimental group 1). Experimental group 2 was also diluted and treated with medium No. 1, but with the addition of 5.6% glycerol and 1.4% DMAC. After saturation of the sperm with the protective substances of medium № 1, it was diluted with medium No 2 containing 4% glycerol and 1% DMF (experimental group 1) and 4% glycerol and 1% DMAC (experimental group 2). Control samples were diluted according to a standard two-moment protocol using 7% glycerol in medium No. 1 and 5% glycerol in medium No. 2. Cryopreservation of spermatozoid was carried out by direct immersion of standard flat metal cassettes with coated granules in a liquid nitrogen medium. At the same time, cooling was carried out in the following mode: 4°C to minus 10°C at minus 3°C/min and from minus 10°C to minus 80°C at minus 40°C/min. Deconservation of spermatozoa was carried out at a temperature of 38–39°C. Cows were inseminated by the recto-cervical method. The results. The use of penetrating cryoprotectants from the amide group - dimethylformamide and dimethylacetamide - in media for sperm dilution and cryopreservation ensures a certain increase in the motility of germcells by 5.9% and 9.0%, respectively. The positive effect of the composition of cryoprotectants was also noted regarding the survivat of sperm after deconservation. Thus, the survival rate in the second experimental group was 0.67 hours or 10.3% higher than in the control group. The environments supplemented with cryoprotective substances of the amide group ensured sufficiently high sperm survival at body temperature (38ºС), which significantly exceeded the established minimum physiological norm (5 hours). In percentage terms, this excess was 34.6% and 42.6%. Conclusions. The feasibility of using combinations of endocellular cryoprotectants made from glycerol and dimethylformamide (DMF) or glycerol and dimethylacetamide (DMAC) in cryoprotective media (diluents) for bull sperm has been proven, which increases the quality characteristics of the biomaterial.