Abstract. The mirror carp (Cyprinus carpio) belongs to the cyprinids, the world's largest and most important fish family in aquaculture. The fat content and the fillet yield are important parameters in the marketing of carp. Although the influence of the environment on the body composition of the carp has been well studied, there is little research in the field of breeding. For this purpose, precise phenotyping is indispensable. Therefore, during this study a total of 33 mirror carps were examined using computed tomography (CT) technology. First, the fish were examined alive. Total body weight and linear measurements such as lengths, height and circumferences were measured, and ultrasound was used to determine the back-fat thickness. The fish were then slaughtered and whole body scans of all fish using CT were made. The carps were filleted and the fillets with skin were chemically analyzed. In order to predict the chemical fillet fat content, thickness measurements and volume calculations of the back fat were carried out using CT. Compared to the CT-based back-fat thickness measurement correlated with the results from the chemical analysis (R2=0.62), the CT-based volume measurement of the back fat leads to a higher coefficient of determination (R2=0.85). Prediction results can still be improved by adding linear measurements. The in vivo ultrasound (US) examination of the back-fat thickness was compared with the CT back-fat thickness results. The measurements of the back-fat thickness took place at similar positions in the fish. Coefficients of determination (R2) of 0.63 to 0.77 were obtained. The back fat in mirror carp proved to be an interesting area for determining the fillet fat content. The evaluation of the fillet yield resulted in a mean value of 42.89 % with a standard deviation of ±2.43. Fillet yield (%) correlated with CT-based fillet thickness measurement resulted in a moderate coefficient of determination (R2 of 0.45). A similar coefficient of determination was achieved with selected linear measurements.

Research on the impact of the European beaver population on the species composition of forest stands was conducted in Wigry National Park, situated in north-eastern Poland. The study was conducted in forest stands on a dystrophic lake of the ‘suchar’ type,� i.e. a dystrophic lake with high acidity and low species diversity of vegetation on its shores, on the banks of a river and a drainage ditch, and in a field environment. A ThermoPro TP8 thermal imaging camera with an uncooled microbolometer matrix of 384x288 pixels was used to confirm that the designated observation areas were inhabited by beavers. In each research area five transects four metres in width were established, where measurements were taken of five classes of trunk damage and two classes of trunk diameter. We examined the seasonal preferences of beavers in gnawing particular species of woody plants. An analysis was performed for each environment. The results indicate that after an average 15-year presence of beavers in the areas, which they inhabited rotationally, the percentage of healthy woody plants was 73.09%. Of the 17 species of woody plants, the ones most readily cut down by the beavers were grey willow (25.19%) and common hazel (32.36%). The analysis demonstrated that the rodents showed the greatest interest in plants with a trunk diameter of <10 cm (98.28%). The river and drainage ditch were the most exploited environments; here beavers cut down 40.27% and 42.70%, respectively, of the available woody plants.

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The correlations between selected egg, embryo development, and chick traits were analyzed in three lines of Japanese quail subjected to intrafamily selection for 28th day body weight (group S) and in three lines of random control birds (group K). The significant correlation coefficients between egg weight and most of the traits observed after the first two days of incubation as well as chick weight and shank length were estimated. Most of the correlations obtained were significant in both groups. No statistically significant differences between groups were confirmed, but there was a lines effect within the groups in most cases and a strong nest effect in every analyzed trait observed.

Figure 1 (a) Comparison of the nucleotide sequence fragments; the red box shows the CHD1-Z gene cutting site by PsuI and the absence in the CHD1-W gene. (b) Results of the PCR-RFLP analysis by PsuI in 2.5% agarose gel (Nusieve GTC agarose). M -mass standard pUC Mix Marker 8