Determination of effective standards for the introduction of fodder additive Aquatan in the diet of rainbow trut with a biological assessment of the influence on fisheries

Abstract

In connection with the global tendency to prohibit the use of antibiotics in animal husbandry, the prospect of using in ichthyopathological practice preparations from plant materials, which are mostly non-toxic, rarely cause side effects, have an antibacterial effect against a wide range of pathogens of bacterial diseases, opens up. One of these preparations is the feed additive Aquatan (Farmatan Aqua) based on ellagitannins from sweet chestnut wood manufactured by Tanin Sevnica (Slovenia). The aim of this work was to study the effect of different dosages of Aquatan on the survival rate, the rate of mass accumulation and the growth rate of rainbow trout reared in the industrial conditions of the cage farm on the waste warm waters of the nuclear power plant and to assess the production and economic efficiency of the application. The tests were carried out for 34 days in February-March 2021 on the basis of an aquaculture cage farm of LLC “Fish Federation”, located in the water area of the waste canal of warm waste water of the Leningrad nuclear power plant (LNPP) in the area of the LNPP-2 industrial zone in the city of Sosnovy Bor, Leningrad Region. The object of the study is rainbow trout yearlings brought from different fish farms. A total of 247,131 specimens were planted, with an average weight of 156.5–235.7 g and a total weight of 43 950.67 kg. The main hydrochemical indicators of water at the enterprise for the trial period met the water quality requirements for growing salmon fish OST 15.372-87. The feeding was carried out with the production compound feed for salmonids of the firm Alltech® Coppens Supreme-22. In experimental cages, fish were fed with compound feed with the addition of the preparation Aquatan at various concentrations (1, 2, and 3 g/kg of feed); in the control, feed without additive was used. As a result of the experiment, a positive effect of the Aquatan additive in dosages of 2–3 g / 1 kg of feed on growth, mass accumulation, survival and feed costs was established, while when adding 1 g / 1 kg of feed, such an effect was not recorded.