Peculiarities of the genetic structure of rainbow trout (oncorhynchus mykiss) groups at the fish farm “Sloboda Banilov”, Chernivtsi region

Abstract

Purpose. Study of the peculiarities of the genetic structure based on genetic‐biochemical markers in age‐1+ and 2+ rainbow trout of the fish farm “Sloboda Banilov”, Chernivtsi region Methodology. We used the methods of vertical polyacrylamide and horizontal starch electrophoresis with own modification. Sampling of biological material and histochemical and staining of gel plates were performed according to generally accepted methods. The frequency of allele and genotypic variants were calculated, actual and expected level of heterozygosis for each individual locus and the level of mean heterozygosis per locus were determined, Wright F fixation index was calculated. Statistical processing of experimental data was performed with the use "Biosys‐ 1" software. Findings. We performed an analysis of the genetic structure of rainbow trout (Oncorhynchus mykiss) groups with the use of genetic‐biochemical markers — esterase loci (EST, EC 3.1.1.1), carboanhydrase (CA, EC 4.2.1.1), isocitrate dehydrohenase (IDH, EC1.1.1.41), superoxide dismutase (SОD, EC 1.15.1.1). We showed the peculiarities of the distribution of allele variants of the studied loci of rainbow trout. The genotypic composition of biochemical system loci supposed the surplus of fish with heterozygous genotypes by SOD locus in age‐1+ fish (Go=26; Ge=15.3), χ2=15.4, Р<0.001, as well as by EST loci (Go=22; Ge=14.6), χ2=7.9, Р<0.01 и SОD (Go=22; Ge=14.9), χ2=6.8, Р<0.01 in age‐2+ fish. It was found that the investigated groups of fish were characterized by high level of heterozygosis by SOD locus (Ho=73.3–86.7%) compared to the expected value (He=49–50%), Р<0.001–0.01. We observed insignificant prevalence of the actual level of mean heterozygosis over the expected values in age‐1+ fish (Ho=59.9%, He=49.7%, F=–0.205) and age‐2+ rainbow trout (Ho=68.3%, He=48.8%, F=–0.399) that indicate on the necessity to stabilize their genetic structure. Originality. For the first time we performed an assessment of the genetic structure based on genetic‐biochemical markers and calculated the level of heterozygosis in age‐1+ and 2+ rainbow trout reared at the fish farm “Sloboda Banyliv” of Chernivtsi region. Practical value. Results of the study can be used for solving various tasks of group and individual identification of populations when forming the stocks for optimizing their genetic structure. Experimental data of the frequency of allele and genotype distribution will be used for studying the effect of artificial selection factors in the process of rainbow trout adaptation to new living conditions.