The dissertation is devoted to scientific and economic substantiation of usage efficiency of prebiotic «Actigen» in feeds which is produced on the basis of mannan oligosaccharides (MOS) while cultivating age–1+ carp, according to a complex estimation of productive, physiological and biochemical indicators of their organism. The research was carried out in laboratory and production conditions, following the generally accepted methods in fish farming.
The feasibility of using «Actigen» in feeding at the rate of 0.025; 0.050 and 0.075% by weight of feed during 60 days of the growing season was grounded for the first time.
The average weight of age–1+ carp in the experimental groups exceeded the control, respectively, by 6.3, 21.3 and 1.3%; survival — by 2.3; 4.0 and 1.1%; fish productivity — by 10.0; 31.0 and 1.2%. At the same time, the feed conversion rate as a result of the introduction of 0.025 and 0.050% of «Actigen» decreased by 6.7 and 20.0%, respectively, relative to this indicator in the control.
For the first time there was performed the analysis of feeding efficiency in the composition of granular feed of 0.025 and 0.050% «Actigen». It was found that the average weight of fish was higher, respectively, by 11.9 and 22.2% compared to Control; survival rate — by 2.1 and 4.0%; fish productivity increased by 12.1 and 23.1%, and the feed conversion rate was lower by 9.5 and 19.1%. In this case, the cost of feed consumed per 1 kg of weight gain in the control group was higher by 9.2% than when fed with a prebiotic in the amount of 0.025%, and 16.1% than when fed with the addition of 0.050% prebiotic. There was an increase in profit with carp farming when feeding prebiotic in the amount of 0.025% by 20.9% relative to control, and with the introduction of 0.050% prebiotic — by 33.6%. Therefore, the most positive dynamics of change of the investigated indicators as a result of addition of prebiotic in the amount of 0.050% granulated compound feed is established.
As a result of feeding prebiotic in the extruded feed, the average weight of fish exceeded the control variant by 11.5%, and fish productivity was higher by 22.7%. There was also a decrease in feed conversion rate by 20%, although the survival of fish in the control was 2.3% higher. It was analyzed that the cost of feed consumed per 1 kg of growth of age–1+ carp in the experimental group was lower by 35.4%, respectively, the profit increased by 43.3% compared to the control.
It was determined that when feeding carp grain mixture to age–1+ carps, the average weight of fish in the experimental group was higher by 12.9% compared to the control, survival — by 3.4%, fish productivity — by 16.3%. As in previous studies, the feed conversion rate was lower in the experimental version (by 16.7%). It is established that as a result of experimental feeding the additional profit, in comparison with a control variant, at the level of 19.1% is received. The cost of feed consumed per 1 kg of weight gain of fish was 4.1% higher.
In accordance with the results of fishery indicators, as well as a comprehensive analysis of physiological, biochemical and histological parameters that determine the functional state of the organism, for the first time there were established standards and methods of application of the additive in the cultivation of age–1+ carp. Economically justified methods of using prebiotic based on mannan oligosaccharides «Actigen» in the amount of 0.050% in the feed while cultivating age–1+ carp during the growing season have been developed. In order to obtain optimal economic performance, the use of «Actigen» in the composition of granular or extruded artificial feed has been proposed.
