EVALUATION OF THE EFFECTIVENESS OF DIFFERENT TYPES OF FEED ADDITIVES IN AQUACULTURE

Abstract

The creation of low-cost feeds that will increase the productivity of fish farming activities by accelerating weight gain, increasing the survival rate of young fish and improving fish immunity has become a major challenge for modern aquaculture. A potential solution to this problem may be the introduction of various feed additives to existing feeds, including enzyme preparations, attractants, microalgae and their compositions. In this study, we compared the effect of different types of feed additives and their combinations on weight gain, linear body size and total protein levels in the muscles of Carassius gibelio. The study was conducted in the recirculation system of the Laboratory of Hydrobiont Biotechnology of the Educational and Research Institute of Biology, Chemistry and Bioresources of Yuriy Fedkovych Chernivtsi National University. Feeding was carried out for 42 days with pelleted feed with functional additives. The commercial fish feed “Aller Bronze” with a pellet diameter of 3 mm was used as a basis. The enzyme preparation “Protosubtilin G3x A-120”, an industrial sample of betaine hydrochloride 96% from Carp Classic Baits, and green algae biomass Chlorella vulgaris were used as feed additives. It was found that the highest average daily weight gain of silver carp was observed for fish whose diet contained a multi-enzyme preparation and its composition with microalgae. These indicators differed significantly from those of the control group, the difference between which was almost 74% and 72%, respectively. As for the rest of the experimental groups, at the first stage of the experiment, weight loss of Carassius gibelio was observed. The highest average daily increase in linear dimensions of silver carp was observed in the groups fed with compositions of a multi-enzyme preparation with microalgae and an attractant with microalgae. The values of these groups were 0.30% and 0.37%, respectively.  As a result of comparison with the control group, it can be stated that the difference was about 27% and 40.5%, respectively. The indicators of the other experimental groups during the experiment almost did not differ from those of the control group. It was also found that the highest protein content in the muscles of Carassius gibelio both on day 21 and 42 was observed in fish fed with compositions of the enzyme preparation with microalgae: 57.2 mg/g and 52 mg/g. These indicators differed significantly from those of the control group, the difference between which was 23% and 15%, respectively. The lowest values compared to the control on day 21 were in the group that consumed feed with attractants, namely 37.19 mg/g. On day 42, the performance of the other groups was at the level of the control group. Thus, we can summarize that the use of the multi-enzyme preparation “Protosubtilin A-120” and microalgae as feed additives has a positive effect on changes in both linear dimensions, weight gain of Carassius gibelio and the total protein content in fish muscles