STUDY OF THE EFFECT OF FEED ADDITIVE OF SODIUM HUMATE FOR STERLET BY THE CAGE METHOD OF GROWING

Abstract

The article presents the results of an experiment to assess the effect of feed additive of humates on the growth rate and survival of different age groups of sterlet (Acipenser ruthenus L., 1758) and the conversion of fish feed for keeping in aquaculture. Based on the analysis of sources of scientific and technical information, it was found that humic drugs have long been used in crop production as growth stimulants and microfertilizers, and in animal husbandry - to normalize metabolism, treatment of digestive diseases and general stimulating effect on the body as a whole. Analysis of data on the use of humates in aquaculture indicated the presence of a positive effect of these compounds on individual cultivation objects. The small amount of information on the use of humates in fish farming has led to the conclusion that this direction of fish farming intensification is still insufficiently studied, and that studies of the impact of humic substances on aquaculture objects are not comprehensive and mainly concern the assessment of individual effects of biologically active action of the compounds on fish. The available information gave grounds to speculate about the prospects for the use of humates in sturgeon farming. To test this assumption, a series of experiments was conducted on the feeding of sterlet feed with the addition of sodium humate. The research was conducted in 2018, 2020 and 2021, in the production conditions of the cage fishery, located on the Kaniv Reservoir. The effect of different concentrations of sodium humate feed additives on one- and two year old sterlet was evaluated. It was found that the addition of sodium humate to fish feed in concentrations of 60, 100, 120 and 200 mg / kg of feed did not significantly affect the growth rate of sterlet. Thus, the advantage of experimental variants over the control for this indicator was insignificant, in the range of 1.0-1.6%. The effect of sodium humate on the survival of this year sterlet, for their cultivation in gardens. At the same time, the best, by 6.7-17.4%, feed conversion with the addition of humates by one- and two-year-old sterlet was noted. According to the results of the experiments, the best result was obtained in the variant using a feed additive of humates at a concentration of 200 mg / kg of feed. It is considered promising to continue the study of the impact of feed additives of humates on the growth and survival of valuable aquaculture objects under different housing conditions, in particular in closed recirculation aquasystems (RAS), as well as finding the optimal concentration of these additives in feed for different species and age groups of fish.