EVALUATION OF THE EFFECTIVENESS OF THE IMPLEMENTATION OF COMPONENT STAGES OF SPERM CRYOPRESERVATION IN BROWN TROUT (SALMO TRUTTA MORPHA FARIO LINNE)

Purpose. To conduct the approbation of the previously developed dehydration-vitrification method on the sperm of brown trout with a rough estimate of component stages and process steps in the cryopreservation of the biological object: temperature adaptation, cryoprotector selection, of freezing-thawing mode, and cryopreservation method in general. Methodology. We developed and worked out the dehydration-vitrification method for freezing sperm of different fish species. Data collection and processing were performed by standard fish breeding techniques. Preparing and dilution of sperm by cryoprotective medium were carried out according to approved instructions. Findigs. We examined the possibility of brown trout sperm cryopreservation with the aid of the developed dehydration-vitrification method. The following conditions for cryopreservation of the biological object were determined: media and cryoprotectors, freezing-thawing modes. The effect of the technological steps of sperm cryopreservation process in brown trout on the reduction in preservation (S) and efficiency (W) was analyzed. The preservation of thawed sexual cells in brown trout with 90% initial activity of native sperm was 25%. The total efficiency of cryopreservation process was 28%. Duration of thawed sperm storage with its capacity for active translational movement after activation in water in different samples was about 15?30 seconds. It was noticed that the cause of decline in the efficiency of the cryopreservation process are complex factors such as various pH values, osmotic pressure of water and ejaculate dilution medium. These factors determine individual characteristics of biological objects and cryoprotective medium composition. Originality. The previously developed dehydration-vitrification method allowed obtaining the reliable result for sperm cryopreservation in browm trout for the first time. Practical value. The study showed the positive effect of applying the developed method and selected modes of sperm cryopreservation in brown trout.