Increasing the efficiency of growing carp in ponds by improving their diet

Purpose. The aim of the study was to investigate the effect of the experimental composition of artificial feeds on the productive performance and economic component of growing carp in ponds. Methodology. The study was conducted in 2023 in ponds of the State Enterprise “Nyvka” (Kyiv). Two groups of Nyvka scaly carp (1+) were formed, which were grown in analogy 0.5 ha ponds at a stocking density of 1.5 thousand fish/ha. The control group of fish was fed with a commercial feed with a protein content of 25 % for 112 days. The feed of the experimental group of fish was supplemented with a complex of feed additives: 0.2 % of the phytogenic additive Inulin and 0.04 % of precipitated sulphur (feed). The study results were analysed using methods generally accepted in fish farming. During the growing season, similar growing conditions and systematic monitoring of the physicochemical parameters of the aquatic environment and the development of the natural food supply in the experimental ponds were ensured. After catching, size and weight parameters were studied, weight gain and the economic component of carp rearing were analysed. Findings. During the period of carp growing, the water conditions did not differ significantly and met fish farming standards. The water temperature ranged from 18 to 28°C. The average seasonal values of the main hydro chemical parameters were within the normative values, except for some excess of free ammonia (0.11 – 0.20 mg/dm3) and iron (1.48 – 1.61 mg/dm3), as well as a significant increase in chloride content (112.9 – 113.3 mg/dm3), but this phenomenon is typical for the water supply source of this farm. The development of the natural food supply in the ponds was satisfactory, the average seasonal biomass of phytoplankton was at the level of 23.14 mg/dm3 in the control, 43.0 mg/dm3 in the experiment, zooplankton — 7.26 and 13.05 g/m3, respectively, zoobenthos — 0.63 and 0.44 g/m2. The results of the study showed the effectiveness of experimental carp feeding in ponds. It was found that the average weight of the caught fish at the end of the growing season in the experimental group was 4.4 %, and, accordingly, fish productivity was 6.0 % higher than in the control group, and the feed conversion rate was 7.4 % lower. Considering the cost of fish seeds and feed spent on growing, 7.3 % of additional profit was obtained by feeding the experimental diet. Originality.For the first time, the effectiveness of the complex use of Inulin and feed sulphur in carp feeding was determined in accordance with the pharmacological characteristics of these feed additives, productive and economic parameters of cultivation. Practical value. As a result of the implementation of the proposed method of improving the digestibility of feed components, it will be possible to increase the fish productivity of ponds and, accordingly, reduce feed costs for cultivation, as well as improve the quality of fish products. This creates an opportunity to expand the use of semi-intensive and resource-saving pond aquaculture technologies.