Characteristics of the brood stock of Nesvych intrabreed type of Ukrainian framed and scaly breeds of carp based on the complex of productive and reproductive parameters

Purpose. To provide an assessment of the complex of productive and reproductive parameters of the brood stock of the Nesvych intrabreed type of Ukrainian framed and scaly breeds of carp grown in pond conditions of the Polissia zone. Methodology. The study was conducted at fish farms of Lviv and Volyn regions of Ukraine during 2004-2024. The material for the study was sexually mature carps of the Nesvych type of different ages. The main fish productive and biological parameters were studied during spring valuation according to generally accepted methods in fish farming. Exterior evaluation was carried out according to weight and the main parameters of body structure. Measurements were made with a centimeter tape with an accuracy of 1 mm. Individual weighing of older age groups was carried out on electronic scales PROK VT-150-R1, juveniles - TS-500. Based on the results of the measurements, the main exterior parameters were analyzed and determined — girth, body length to height ratio, head length. The ejaculate volume was determined using an Eppendorf pipette-dispenser with an accuracy of 0.1 cm3. Sperm movement activity was determined using a Zeiss Axiostar plus microscope with a 20x/0.40 phase-contrast objective. The number of spermatozoa in cm3 was calculated using a Macler camera. Calculation of the absolute working fertility was carried out by the weight method, with the calculation of the number of eggs in 1 g and the subsequent determination of the weight of 1 egg. Relative working fertility was defined as the ratio of working fertility to body weight. Findings. The study showed that carps of the Nesvych intrabreed type had exterior parametetrs typical for Ukrainian carp breeds. At the same time, the working fertility of first-time spawning females was in the range of 328.1 - 522.7 thousand eggs, age 6-8 females - 645.7 - 1178.3 thousand eggs, older age groups - 536.2 – 1014.0 thousand eggs. With the average ejaculate volume of 7.6 – 8.3 cm3 in first-spawning males and re-spawning ones 14.9 – 21.3 cm3, active movement of spermatozoa after their activation was observed: 33.1 – 48.6 s and 56.3 - 59.3 s, respectively. At the same time, the working fertility of males was 90.1 - 443.2 billion spermatozoa. The positive response of female Nesvych carp to pituitary stimulation exceeded 95%. Originality. The results of 20 years of selective-breeding work with a representative of aquaculture in the western region of Ukraine are highlighted. In particular, weight dynamics, main exterior and reproductive parameters of brood fish of different ages of brood carp stock of Nesvych intrabreed type of Ukrainian framed and scaly breeds, which were presented and successfully passed the state approval in 2023, are summarized. Practical value. High fish productive and biological parameters of broodstocks of the Nesvych inbred type allow recommending them for use for the purpose of commercial cultivation.