Characteristics of the first-generation crosses obtained from the reciprocal crossing of brood Nyvky few-scaled carp and framed carp of the Antoniny-Zozulynets indobreed type

Purpose. In fish farming, the use of purebred reproduction and crossbreeding is used to increase productivity, improve quality, or preserve genetic diversity. These methods play an important role in the improvement of breeds and contribute to the development of aquaculture as one of the leading branches of agriculture. The main goal of our scientific work was to determine a set of productive and biological parameters of the offspring obtained by combining the Nyvky few-scaled and the Antoniny-Zozulenets type of the Ukrainian framed breed of carp in comparison with the parental forms. Methodology. Experiments were conducted at the PrJSC “Khmelnytskrybhosp”. Control groups were obtained using purebred crossing, experimental groups - using their crossbreeds. Comparative analysis between the control and experimental groups was carried out by conducting scientific and economic experiments. The breeding stock of the original parental forms was evaluated according to the exterior and fertility parameters. The study of productive and biological parameters was carried out in accordance with the methods common in fish farming and ichthyology, which are used in international practice. Pituitary injections were used to reproduce the selected individuals. Eggs and sperm were obtained from first spawn age-4-5 females and males. Spawning was carried out in the conditions of the hatchery of the Medzhibyzh fish farm. Each individual was tagged and given an individual fifteen-digit electronic number. The juveniles of the experimental and control groups were reared in 0.25 ha ponds of the wintering system, which were treated with quicklime in the amount of 150 kg/ha before stocking. Ponds were stocked with three-day-old larvae that switched to exogenous nutrition at a stocking density of 100,000 ind./ha. Feeding was carried out with high-protein feeds in accordance with the feeding schedule with adjustments of the daily rate depending on water. Test catches were carried out in the first half of each month. The minimum sample in each group was at least 25 ind. Productive, biological and exterior parameters were subjected to statistical processing using the ANOVA statistical package in Microsoft Office Excel (2016). The criteria for the analysis of values were their average value, the standard error (M±m) and power. Findings. Fish selected for the study met the morphometric requirements for brood fish of the second class according to phenotypic parameters. During the incubation campaign, the highest total fecundity were obtained in the group of Antoniny - Zozulenets framed carp females. The total weight of the obtained eggs was 13.2-19.6% of body weight. The percentage of hatching of 3-day-old larvae from fertilized eggs was in the range of 87.62-90.48% with a slight advantage in crossbred groups. Based on the results of the incubation campaign of 2023, control and experimental groups of 25,000 ind. were formed. The initial larvae weight during stocking was 1.82-1.86 mg, starting from June, the superiority in terms of average weight was observed in crossbred forms, which increased until the end of the growing season. A statistically significant difference in the weight of young-of-the-years was only between purebred crossings and crossbred combinations at td = 2.68 р ≤ 0.05. Originality. For the first time, the productive and biological parameters of crosses of few-scaled Nyvky and framed Antoniny-Zozulenets carps were obtained and studied for the use of their reciprocal crossing, and the value of the obtained heterosis index was determined. Practical value. The practical value of the results of our study lies in the determination of the efficiency of rearing young-of-the-years of individual intrabreed types of the Ukrainian framed breed of carp in comparison with the original forms.