Rybohospodars'ka nauka Ukrayiny (Fisheries Science of Ukraine)

5-28

Authors: V. Lytvynenko, D. Khrystenko, G. Kotovska, N. Kolesnik, M. Simon

Purpose. To analyze an array of special scientific literature and summarize the obtained information on the commercial exploitation of the Kуiv reservoir as a fishery water body. To review main abiotic conditions of the reservoir, which exist and form the specificity of its commercial use by the fishery industry of Ukraine. To highlight the historical course of their impact on the fish fauna of the Kyiv Reservoir and general forecasts for its future transformations. Findings. An overview of scientific publications devoted to the specifics of commercial exploitation of the Kуiv reservoir as a fishery water body from the moment of its creation to the present day were presented. In particular, following was analyzed: hydrological regime, color and chemical composition of water, oxygen regime, accumulation of heavy metals, formation of bottom sediments and landscape. In addition, the radioecological situation in the reservoir was anazyed, both general and in three most significant areas for fisheries — in bottom sediments, macrophytes, and fish fauna. The literature data on the specificity of the above-mentioned abiotic factors in this reservoir, which form the hydro-ecological feature of this reservoir, were generalized. The main directions of their influence on the ichthyofauna of the Kуiv reservoir, which affect the possibility of its commercial exploitation, were described. The share of anthropogenic origin in the composition of the above-mentioned abiotic factors and the consequences of its impact were highlighted. The perspective ways of further development of the Kiev reservoir as a fishery water body of strategic importance for Ukraine were shown. Practical Value. The review may be useful for scientists, PhD students, students, government authorities, and private entrepreneurs involved in research process or exploatation of aquatic living resources in internal water bodies, primarily in the Kуiv reservoir.

40-55

Authors: A. Mruk, A. Kucheruk, L. Galoyan, N. Mykhailenko

Purpose. To study the possibility of obtaining highly productive intergeneric salmonid hybrids between rainbow trout and brook trout; brown trout and brook trout; rainbow trout and brown trout, as well as to develop methodological approaches and determine of optimal variants of hybrid crosses. Findings. In order to obtain intergeneric hybrids, we used six variants of hybrid crosses with brood fish of three salmonids belonging to three families (Salmo, Oncorhynhus, Salvelinus). The study used age-4 female rainbow trout with average body weight of 3296.8 g, Fork length was 62.6 cm, and the average working fecundity was 7420 eggs. Age-3 rainbow trout males had an average body weight of 1613 g and an average body length of 49.8 cm; age-3 brown trout females had an average body weight of 453.8 g and average working fecundity of 1540 eggs, and males had an average weight of 458.7 g; age-3 brook trout females had an average weight of 809.7 g and a length of 38.9 cm with working fecundity of 1732 eggs, and age-4 males had an average weight of 1212.8 g and an average body length of 46.0 cm. Twelve variants of fertilization were used: six variants at normal water temperature and six variants after a temperature shock. Under natural conditions, the creation of intergeneric hybrids is almost impossible, except for variants between brown trout and brook trout, which is due to the similarity of their biology. However, the efficiency of this cross is low and economically impractical for fish farmers. When applying the temperature shock during fertilization, hybrids proved to be the most effective, where females were rainbow trout, and males were brook trout and brown trout. The average weight of young-of-the-year intergeneric hybrids was, depending on the species of fish, from 8 to 54 g. The highest results were obtained for the creation of hybrids where following broodstock was used: ♂brook trout Х ♀brown trout; ♂brown trout Х ♀rainbow trout. In these variants of crossbreeding, the survival rate of young-of-the-year during the period of cultivation was 94.8 and 92.8%, respectively. In particular, the above hybrids did not suffer from infectious diseases during the growing period. Originality. New data on the development of methods for obtaining viable offspring of newly created hybrids were obtained, and the optimal variants of crossing between females and males of these salmonids were determined. Practical value. The results can be used for artificial breeding of salmonids in specialized farms that will allow obtaining high quality products and reducing their costs.

72-86

Authors: Yu. Krot, D. Medovnyk, Yu. Krasiuk, D. Kudriavtseva

Purpose. To study the peculiarities of relationships between the aquatic environment and the extruded feed residues in the circulating aquaculture systems intended for growing Clarias gariepinus, and changes in the concentrations of inorganic nitrogen compounds and phosphorus phosphates. Methodology. The object of study is the quality of the aquatic environment when modeling the food load in accordance with feeding standards of different age groups of Cl. gariepinus. Water quality in experimental tanks was determined by analytical methods. Findings. It was found that the intake of extruded feed residues into the aquatic environment leads to a deterioration in its quality due to an increase in the concentration of compounds of inorganic nitrogen and phosphorus of phosphates, which negatively affects the vital activity of Cl. gariepinus. Nitrification processes are activated under conditions of sufficient dissolved oxygen content in the environment. The overload of the aquatic environment with organic matter promotes the bacterial transformation processes of nitrogen and phosphorus compounds, which are characterized by the predominance of the ammonification process and the suppression of oxidative processes. Upon completion of the mineralization of the excess organic matter, the appearance of a sufficient amount of dissolved oxygen activates ammonium oxidation and intensifies nitrification process. The leading factors in the ammonification and nitrification processes in an environment saturated with organic matter include the dissolved oxygen content, which regulates the activity ratio of anaerobic amonifying and aerobic nitrifying microflora. Optimum aeration in Cl. gariepinus cultivation systems is determined not only by the direct physiological needs of fish, but also by the need to maintain a sufficient content of dissolved oxygen to ensure nitrification processes. Originality. The study investigated the effect of the food load on the quality of aquatic environment in the circulating aquaculture systems for Cl. gariepinus rearing. Practical value. The study results can be used to optimize Cl. gariepinus growing methods in circulating aquaculture systems with adjustable parameters at high stocking densities.

101-114

Authors: O. Honcharova, O. Sekiou, P. Kutishchev

Purpose. To study the functional status in the body of the common carp Cyprinus carpio (Linnaeus, 1758) after the addition of biologically active substances in feed composition as an adaptogene and corrector of metabolic processes including the antioxidant system, catalase activity in carp body. Methodology. The experimental part of the study was performed at the laboratory of the Scientific and Research Laboratory “Aquaculture Perspectives”, Scientific and Research Laboratory of “S. Pentelyuk Physiological and Biochemical Studies”, Scientific and Research Laboratory of Ecological and Chemical Analysis and Water Monitoring of the State Education Institution “Kherson State Agrarian and Economical University” and at the laboratory of the “Kherson Production and Experimental Hatchery of Ordinary Fish Breeding”. The duration of the experimental part was 30 days. During this period, visual observation of the fish was carried out, biological material was collected for the study in accordance with the current methods in fish farming. Cytological studies of blood were carried out on smears using Micromed MDC-500-5MP eyepiece camera. ThermoMix equipment was used to transport biological material to the laboratory. The hydrochemical parameters in tanks of the recirculating aquaculture system (RAS) were investigated by express methods (tests) with the corresponding recording of results in the work journal. The reaction and ethology of the common carp Cyprinus carpio to the light was carried out using digital equipment and a LDT test. Findings. The obtained results demonstrated the positive effect of the feed factor as an adaptogene and growth stimulator on the redistribution of metabolic energy in the carp body, which in turn had a stimulating effect on the development rate and improved the general functional status of the fish body. The paper presents the results of morpho-functional, biochemical parameters of carp blood in ontogenesis when grown in recirculating aquaculture systems against the background of the application of elements to improve technological aspects while improving the adaptive capabilities of the fish body. It was found that the feed factor, when introduced into the general economic ration, promoted an increase in the average carp body weight in the experimental group, improved the parameters of homeostatic equilibrium in comparison with fish in the control group. Positive results of a scientific and experimental study on the use of the additive as an adaptogene were obtained; it was studied with the aim of activating protective mechanisms, metabolic processes of aquatic organisms under constant or systematic exposure to stress factors of a technological nature. The study showed that the body weight, yield, total number of erythrocytes, hemoglobin content, total protein, and the level of catalase activity in the experimental groups of fish exceeded these parameters in the control group. The results obtained allowed noting the activation of the antioxidant system, the restructuring of physiological and biochemical processes, mobilization systems in the carp body in the experimental group. Originality. We found a correcting effect of the feed factor on metabolic processes, the adaptive capacity of the fish organism, as well as an increase in the resistance of the body as a whole. After implementing the technological scheme of cultivation of a feed factor of natural origin as an adaptogene against the background of the influence of technological stress factors, we found a correlation between the morpho-functional, biochemical parameters of carp blood and stress markers. Addition of biologically active substances of natural origin with a pronounced adaptive and correcting physiological and biochemical parameters into the general diet of carp improved the adaptive capacity. The antioxidant system was activated against the background of the action of technological factors. Practical value. The results of scientific and experimental studies of the functional status of carp body under the influence of technological factors were presented. Parameters of the development of carp in ontogenesis when growing in recirculating aquaculture systems against the background of the introduction of multilevel elements to improve technological aspects were studied. The results demonstrated the positive effect of biologically active substances invlufrf in the feed mixture, in particular, activation of the growth rate, increase in body weight, and yield.