Effect of mineral betonit on chemical composition of carp (Cyprinus carpio Linnaeus, 1758) muscles

Purpose. To study the effect of bentonite mineral added to the basic diet of age-1 carps on the content of lipids and their individual classes as well as on the chemical composition of muscles to establish the efficiency of its optimal rates for carp feeding. Methodology. The study was conducted at the laboratory of fish feeds and feeding of the Institute of Fisheries NAAS in conditions of aquariums-analogues for 27 days. The object of the study were age-1 Nyvka scaled carp. The experiment included one control group and five experimental groups. Carp of experimental groups were fed with feeds with added bentonite ratios as follows: 0.1%, 0.2%, 2%, 5%, and 10%. The determination of the content of common lipids was carried out by Folch's weight method, the content of individual lipid classes by thin-layer chromatography. The weight content of protein was determined by Kjeldahl method, fat content – by S.V. Rushkovsky method. The experimental works were conducted according to generally accepted fisheries methods. Findings. The study analyzed the effect of feeding age-1 carps with non-activated bentonite clay in the composition of basic ration on biochemical parameters of fish organism. A comparison of the efficiency of the use of this dietary supplement at different concentrations during fish growing in laboratory conditions was carried out. The conducted experimental studies showed that addition of bentonite to feed composition at an amount from 0.2% to 5% of feed weight contributed to an increase in triacylglycerol and decrease in cholesterol ester content in the muscles of age-1 carp. In addition, a 10% increase in phospholipids (P<0.5) after the addition of 2% bentonite to the feed relative to the control was observed. The content of total lipids in carp muscles was highest after adding bentonite to feed composition at an amount of 10% as well as a significant increase in the content of dry substance, protein, and fat compared to control by 6% (р<0.05), 19.4% (р<0.01) and 1.7%, respectively, was observed. Feeding with bentonite at the amount of 2 and 5% of the feed resulted in an increase in protein content by 16.2% (p <0.01) and 10.2% (p <0.05), respectively. Originality. The study in aquarium conditions allowed studying the effect of bentonite on the nutritional value of meat, the content of total lipids and the ratio of their individual classes in the muscles of age-1 carp. According to the results of researches, the effective doses of the addition of this mineral to the ration composition were established. Practical value. The study of the efficiency of addition of bentonite to the basic diet of carp in laboratory conditions is topical, since there are problems of finding tools for increasing the productivity of fish in the process of rearing, which require new ways and methods for their solution. In view of the positive obtained results, studying the advisability of the use and finding the rates of bentonite supplementation to carp diet are promising and have practical values.