Evaluation of fishery biological parameters of rainbow trout using experimental feeds

The article presents the results of studies of the dynamics of rainbow trout growth to marketable weight using feeds from different manufacturers with different composition and nutrient content. Rainbow trout with live weight from 100 to 850 g were used in the experiment. To conduct the experiment, two groups were formed: a control group and an experimental group, 60 fish in each. The first control group was fed with Biomar Efico Alpha 790 trout feed. Trout in the experimental group received experimental feed developed at the farm. The experimental feed is made from high-quality Ukrainian ingredients that have good nutritional and taste characteristics, which stimulates feed consumption by fish, and is balanced in terms of basic nutrients and biologically active substances. The effectiveness of the use of pelleted feed for trout was evaluated by such indicators as: yield from cultivation, fish productivity, feed consumption, absolute and relative weight gain of trout during cultivation. At the same time, the physicochemical parameters of water were monitored throughout the experimental period. When analyzing the results of the dynamics of the hydrochemical regime of the pools, it was found that the indicators fluctuated within insignificant limits during the season, but no significant deviations from the regulatory requirements were found. The duration of commercial trout rearing was 160 days. As a result of rearing, it was found that the ichthyomass of trout in the control group was 5.9 kg or 12.2 % higher than in the experimental group. At the same time, per 1 kg of ichthyomass in the control group compared to the experimental group, the feed conversion rate is significantly higher by 0.425 kg. The yield of the two groups was almost the same and ranged from 93.3–95.0 %. The average weight of juvenile trout at the time of the experiment was 103.2–104.5 g. The results of the study showed that at the end of the experiment, individuals of the control group were characterized by a higher weight, which exceeded their counterparts from the experimental group by 90.2 g, or 10.6 %. In terms of absolute weight gain, the control group also dominated. The results of the study on the average daily weight gain of trout showed the following variability by periods of the experiment: in the control group – from 4.58 g to 5.82 g, in the experimental group – from 2.93 g to 4.71 g. Over the entire study period (23 weeks), the average daily weight gain of the control group was 12 % higher than that of the experimental group.