Comparative characteristics of the effect of probiotics Vetom 2 and Liquafed in growing rainbow trout in ST “Romanov” (Leningrad region)

Abstract

In the conditions of modern industrial fish farms of various types, the risk of bacterial diseases increases. Various probiotic and immunomodulatory preparations are actively used in modern aquaculture. Especially popular are probiotics based on Bacillus subtilus, which are used in the cultivation of carp, sturgeon and salmon fish. Recently, a large positive experience has been accumulated in the use of Vetom 1.1 in fish farming (manufactured by the Scientific and Production Company Research Center, Novosibirsk). At the same time, fish farms actively use Vetom 2, created on the basis of dried spore biomass of Bacillus subtilis and Bacillus licheniformis bacteria. For use in aquaculture, LikvaFid seems to be promising, containing as active ingredients live cultures of the bacteria Bacillus megaterium and Bacillus subtilis (manufactured by LLC BIOTROF, St. Petersburg). Experimental work on the use of probiotics of domestic production LikvaFid and Vetom 2 was carried out at the fish-breeding enterprise Sole Trader Romanov (Leningrad region, Lopukhinka village). A one-year-old rainbow trout was chosen as the object of research. Vetom 2 and LikVafid were administered orally with food by irrigation at a dosage of 5 g/kg and 2 g/kg, respectively, in two courses, the duration of each course was 10 days, the interval between them was 40 days. An analysis of the results of the experimental work showed a statistically significant increase in body weight and length in the experimental groups, as well as a significant increase in the growth rate. The absolute increase in the experiment is 1.4–1.7 times higher than in the control. At the same time, the maximum indicators for almost all significant morpho-biological indicators were found in fish treated with the LiquaFeed probiotic. The relative growth rate in this group is 1.2 times higher than in the control. Research work confirms the beneficial effect of these preparations on the processes of fish digestion. Strains of Bacillus subtilis, Bacillus licheniformis and Bacillus megaterium, due to their probiotic activity, stimulate the growth of normal intestinal microflora. Improving the absorption of nutrients in the gastrointestinal tract, inhibiting the development of pathogenic and opportunistic microorganisms, and stimulating the immune system contribute to a more active growth of rainbow trout.