The purpose. To study molecular-biological features of causal organisms of contagions of fishes of bacterial etiology. Methods. Microbiological, molecular-biological, icthyological. Results. Complex analysis is carried out, and series of conditional-pathogenic and pathogenic bacteria is determined in populations of rainbow trout, sterlet, European catfish, and carp, cultivated in Ukraine. Analysis of a gene 16S rRNK of these bacteria is carried out. Conclusions. Methods of identification are elaborated of conditional-pathogenic and pathogenic bacteria on the basis of polymerase chain reaction.

The purpose. To study productive characteristics of age-2 Galician carp in conditions of industrial growing. Methods. Standard procedures in fish farming and selection. Results. Data are gained on productive features of age-2 Galician carp at various densities of fishes during industrial growing in ponds of Prikarpattia. It is revealed that irrespective of density of fishes Galician carp has high temp of body height. Economic assessment of age-2 Galician carp by exterior parameters is given. Conclusions. Galician carp at growing age-2 fishes in industrial conditions of ponds of Prikarpattia has high economic parameters both on individual mass of fishes, and on the general productivity.

Aims. To analyse highly conserved male-specifi c sequences in Y chromosome of salmonid species and de- velop the conventional polymerase chain reaction (PCR) for rapid identifi cation of fi sh sex. Methods. DNA sequence analysis, phylogenetic analysis, DNA extraction, primers design, PCR and sequencing were used. Results. Using the data from NCBI GenBank, all available sequences of male-specifi c Y-chromosome genes (sdY) in salmonid species were analyzed for specifi c oligonucleotide primer design. The PCR assay for rapid identifi cation of males in rainbow trout Onchorhynchus mykiss, brown trout Salmo trutta, huchen Hucho hucho and grayling Thymallus thymallus was developed. The length of PCR products was in the range of 200–800 base pairs (bp). The specifi city of the amplifi ed fragments was tested by sequencing of PCR products. All PCR products corresponded to the areas of the Y chromosome where the sdY loci are located. The comparison of the amplifi ed DNAs revealed high identity (95–99 %) between the sequences of the rainbow trout, the brown trout, the huchen, and the grayling. The highest identity rates were noted among one specifi c genus and the percent- age of homology was approximately 99 % as shown for rainbow trout O. mykiss. Conclusions. The sex of the mentioned above fi sh species can be readily determined by the PCR assay which allows performing simple identifi cation of “neomales” in the indirect feminization method via the hormonal sex reversal. The assay can be classifi ed as express diagnostics, because the data analysis and the delivery of the generated results to the fi sh-farming site can be accomplished within a day.

The purpose. To study genetic structure of breed herd of Amur carp selected in «Karpatskyi vodohrai» Ltd. (Lviv oblast) with the use of different types of markers and to determine the level of somatic mutagenesis by the microkernel test. Methods. Laboratory researches, computer statistical analysis. Results. Genetic structure of Amur carp on separate types of molecular-genetic markers (DNA-markers, genetic-biochemical systems) is studied. Species-specific features of genetic structure on probed loci are determined. The level of actual and expected heterozygosity is calculated. Increased allele and genotypic variety of genetic structure can be caused by a little heightened intensity of the carried out selection work. The detected excess of heterozygotes on separate loci testifies to presence of stabilization processes of genetic structure. Research of the level of somatic mutagenesis is also carried out at use of micronucleus test. Conclusions. At use of different types of molecular-genetic markers the information on genetic structure of a carp and its variety on genome level is gained. These results testify to the following: genome preserved resistant gene complexes, despite of significant selection effort. The applied genetically-statistical approaches can be used for monitoring genetic structure of groups of a carp of Ukraine, determination of the level of consolidation and phylogenetic links between them with their subsequent genetic certification. Results of researches of the level of somatic mutagenesis at use of micronucleus test shown that the probed group of fishes was characterized by average level of erythrocytes with micronucleus MNE (4,7±0,3‰), low level of lymphocytes with micronucleus and binucleate lymphocytes which total has made 3,5±0,3‰ that in its turn testifies to satisfactory conditions of selection.