Efficiency of using experimental feeds with different levels of nutrition in feeding rainbow trout

Abstract

The article presents the results of research on the growth dynamics of rainbow trout from fingerling to marketable fish using feeds with different compositions of components and nutrient contents. For the experiment, two age groups of rainbow trout individuals, control and experimental, were formed, which were kept in tanks with a total volume of 30 m3 and fed with feeds with different nutrient contents. For feeding the experimental fish, dry pelleted feed for trout was used, which has an optimal balance of cost and nutritive value, resulting in high growth rates with a low feed coefficient. The feed is made from high-quality Ukrainian ingredients with good nutritional and flavor characteristics, stimulating fish feed intake, and is balanced in terms of essential nutrients and biologically active substances, which positively affects the physiological condition of salmonid fish and their growth rates. The daily ration was determined depending on the fish's weight and the water temperature in the tanks according to the feed manufacturer's recommendations. The effectiveness of using pelleted compound feeds for trout was evaluated based on indicators such as fish survival, fish productivity, and feed consumption. At the same time, the physicochemical parameters were monitored throughout the entire experimental period. The duration of growing rainbow trout fingerlings was 245 days. As a result, 3230 specimens of fingerlings with a mass of 25.6 g were obtained in the control, and 3400 specimens were obtained in the experiment with a mass of 28.5 g. The yield from the cultivation was 76 % and 80 %, respectively. Fish productivity was slightly higher in the basin where the experimental group of fingerlings was kept. The total weight of the harvested fish from the experimental group was greater by 14.2 kg. To obtain marketable products, rainbow trout fingerlings were stocked in 30 m3 tanks. The average weight of fish in the control group at stocking was 25.6 g, and in the experimental group, it was 28.5 g. 3100 specimens of fingerlings were stocked in each tank. The duration of cultivation was 215 days. 2805 specimens were harvested from the tanks, 250.5 g from the control tank, and 268.5 g from the experimental tank. The total weight of the harvested fish and fish productivity were slightly higher in the fish from the experimental group. As a result of the conducted research, it was established that feeding fish with feeds differing in nutritional value contributes to increasing the productivity of rainbow trout farming.