The dissertation is devoted to the study of productive, reproductive, genetic features and efficiency of the use of Amur carp males of different genetic origin in industrial hybridization. For the first time we conducted a comparative analysis of size and weight parameters, exterior body built indices and investigated main reproductive properties of age-8- and 9 Amur carp males obtained using cryotechnologies in comparison with those of Amur carp males of local stocks, which are descendants of brood fish brought from the Far East – Lake Hanka (Amur River basin) in the 70-80's of the last century and underwent 8 generations of reproduction. The genetic structure was assessed by genetic and biochemical systems and DNA markers. The characteristics of males by their offspring were given and main piscicultural indicators for commercial cultivation were analyzed.
Carp males obtained using cryopreserved semen were found to have higher mean values of the number of alleles per locus and the effective number of alleles per locus, as well as a higher Shannon index and a broader range of amplicon sizes. At the same time, carp males of both genotypes were characterized by higher values of actual heterozygosity and information polymorphism index at the MFW15 and MFW23 loci.
According to the analysis of productive indicators, cryo-males surpassed the local ones by body weight and length at age-8 and 9. The condition factor of age-8 local carp was 1.96 versus 1.85 in cryo-males; in age-9 fish – 1.72 and 1.55, respectively. The body length to depth ratio of local males was 4.06−4.07, cryo-males – 3.77−3.88. According to the head length index, carps of both genotypes did not differ with values of 23.42−23.75% in age-8 and 21.32−21.40% in age-9. At the same time, the body circumference index increased with age from 1.48-1.55 in age-8 to 1.66-1.79 in age-9 fish. At the same time, brood Amur carp of both age categories were characterized by high total sperm activity (87.5 - 94.4%) and preservation of spermatozoid motility (69-108 hours). Studies of soluble sperm proteins detected the zones of globulins typical for electrophoretic separation of proteins: γ-, β- and α-, albumin and prealbumins.
The average weight of the young-of-the-years (YOY) obtained from age-8 cryo-males was 1.1% lower than YOYs obtained from local carps. Among the offspring of age-9 males, the highest growth rate was 3.4% in YOYs obtained from cryo-males, and, accordingly, the maximum value of fish productivity – 696.1 kg/ha. At the same time, YOYs obtained from cryo-males were characterized by 3.69 and 3.71% higher survival rates. The maximum body height was observed in hybrid YOYs obtained from age-8 cryo-males, at the same time the average values of the condition factor were in the range of 2.28-2.39 and feed consumption did not exceed 4.
According to hematological analysis, YOYs obtained from crossing Lubin females with Amur carp had higher erythrocyte counts in the blood by 45.0 and 39.6%, and lower hemoglobin content by 15.0 and 20.0%, hematocrit – 12.4 and 13.6%. The content of diene conjugates, malonic dialdehyde and SOD in the body of YOYs obtained from age-9 Amur carp males was higher than in individuals obtained from age-8 males. Instead, the former had a lower catalase content.
The yield from winter keeping was higher in yearlings obtained from Lubin females by 2.2 and 4.5%, respectively, according to the experimental groups of carp. At the same time, they had a higher degree of weight loss by 10.7 and 10.9% versus 8.91 and 8.90% in hybrid yearlings of local origin. The decrease in fat content in muscle tissue during the winter period in age-1 obtained from Lubin females was 45.1 and 49.1%, from Galician females – 39.5 and 33.2%, protein - 15.92; 12.29% and 9.85; 16.95% according to the experimental groups.
Among the hematological parameters, those, which significant decreased in comparison with the same parameters of YOYs, were hemoglobin content – by 11.1-16.0% and erythrocyte count in blood – by 8.2-13.9%. The percentage of the reduction in the erythrocyte count in blood was lower in YOYs obtained from cryo-males, both in the first year of the study and the second one. On another hand, age-1 fish of the experimental group of the same generation had the largest decrease in hematocrit – by 11.7 and 13.7%, respectively, compared to the studied years.
The most cost-effective for the cultivation were age-1 hybrids between common and Amur carps obtained from crossing Galician and Lubin females and cryo-males of Amur carp. Due to the high productivity of products (505.3 and 568.9 kg/ha) and reducing their cost (46.8 and 47.0 UAH/ha), the enterprise’s profit increased by 6655 and 7412 UAH/ha, while the profitability of production increased up to 27.74−28.12%.
