Home – Home – Jornals – Contemporary Problems of Ecology 2024 number 2

Studies of the physiological state of three-year-old pikeperch from the lake (natural habitat), ponds and fish farm cages, showed significant differences in the size, mass, biochemical, hematological and histophysiological parameters of fish. Farmed fish have large sizes (length 26.2 cm, weight 242.1 g), comparable to the size of lake individuals (27.6 cm and 278.2 g, versus 23.7 cm and 162.6 g in pond pikeperch), high liver index values (3.68 versus 1.42 and 1.03 % in lake and pond fish, respectively), gonads (0.73 versus 0.15 and 0.08 %) and abdominal fat (8.61 versus 1.87 and 2.30 %). The chemical composition of the body of farmed fish is characterized by a large amount of lipids (9.4 versus 2.5 and 3.6 %, respectively) and nitrogen-free extracts (3.4 versus 2.5 and 2.4 %), muscle - protein (21.0 versus 19.0 and 19.2 %), liver - lipids (26.6 versus 11.1 and 7.5 %, respectively) and nitrogen-free extracts (9.6 versus 1.9 and 2.5 %), and low moisture content (51.7 versus 69.3 and 71.5 %), protein (11.2 versus 16.6 and 17.2 %), ash (0.9 versus 1.1 and 1.3 %) and vitamin C (67.5 versus 87.9 and 97.6 %). The fatty acid composition of muscle lipids of farmed fish was generally comparable to that of lake and pond fish - the main groups of fatty acids were at a similar level: polyunsaturated fatty acids in the range of 37.0-40.6 % of the total fatty acids, saturated fatty acids - 25.5-29.6 %, monounsaturated fatty acids - 28.0 and 23.2 % in farmed and lake fish, and 17.5 % in pond fish. The content of arachidonic acid 20: 4n-6 in farmed fish was extremely low (1.0 versus 8.0 and 11.5 % of the total fatty acids). Liver lipids of farmed fish contained a large amount of oleic acid 18:1n-9 (30.3 versus 16.2 and 15.0 % of the total fatty acids in lake and pond fish) and n-6 polyunsaturated fatty acids (17.5 versus 8.4 and 7.1 %), in particular linoleic acid 18:2n-6 (7.0 versus 1.9 and 0.2 %). The blood of farmed fish, compared to pond fish, differed in a lower content of hemoglobin (64.8 versus 74.8 g/l), an increased content of immature lymphocytes (11.6 versus 6.1 %) and immature erythrocytes (2.2 versus 1.1 %). The gonads of farmed fish were at stage III of maturity with an average oocyte diameter of 478.9 µm; lake fish had two stages of oocyte maturity - previtellogenic oocytes of protoplasmic growth, 62.7 µm in size, and significantly larger vitellogenic oocytes of trophoplasmic growth - 227.6 µm. In pond pikeperch, gonads corresponded to stage II of maturity and oocytes were 58.3 µm in size. Certain differences in pikeperch from lakes, ponds and farm conditions are associated with different conditions of fish keeping and feeding.