Kononenko I. A full evaluation of young sterlet (Acipenser ruthenus L., 1758), which is received using cryobiotechnologies

The dissertation covers the issue of the evaluation of sterlet offspring which is received by fertilizing fish eggs by sperm which was frozen using an improved technology of cryopreservation. We succeeded in enhancing the efficiency of cryopreserving sterlet sperm by diluting and freezing it in solutions №№ 5 and 6, modified creatine monohydrate (3,8 and 7,6 mM), by fructose and carp blood plasma. After the sperm was defrosted, 77,5% spermatozoon were able to move. They were able to fertilize between 68,0 and 85,6% eggs. The cryopreservation was better when the sperm was frozen in granules (0,1 ml) and when seeding (crystallization seeded with steam of moist air) was used. The use of cryopreserved sperm to get the offspring had a positive effect on growing sterlet, thus 1,1–1,3 times enhancing linear and weight indicators of the grown young and 4,0–11,2% increasing the survival of young in comparison with control sperm (natural sperm). Thus, the best results of the weight and length of the young of experimental group № 2 were 5,05 g and 9,09 sm respectively and the survival was 63,2%. The young of experimental group № 1 showed the worst results, that is 4,37 g and 8,87 sm respectively and the highest level of the survival was 70,02%. The young of a control group showed the worst results of the weight and length that is the weight was 3,96 g and the length was 8,39 sm, and the survival was 59,02%. The analysis of the deviations in the development does not show clear anomalies caused by the process of the cryopreservation. All morphological problems which occurred in experimental groups can be explained by the fact that that male and female producers and the young were grown in industrial conditions and its frequency did not prevail the same in a control group. The process of young sterlet feeding in all groups was characterized by a bigger amount of the feed used. In experimental groups №№ 1 and 2 it was 2,6 and 2,3 respectively in a control group it was 2,4. Thus the connection between the process of cryopreservation and the food amount is not revealed. The cost of one robust young sterlet which was born as a result of the egg fertilized with a cryopreserved sperm increased by 32,2% and equals 6,85 hrn and the net profit from sales of one seeding material is 1,67 hrn (2017 price).