Results of the use of strains isolated from the intestinal microflora of juvenile sterlet as probiotics

This paper presents the results of a study examining the probiotic potential of microbial strains isolated from the natural microbiota of sterlet (Acipenser ruthenus). The strains studied were Enterococcus muntdii, Lactobacillus plantarum, and Bacillus licheniformis 2336 and 162 St. The study was conducted using groups of similar in a recirculating aquaculture system (RAS) for 60 and 70 days. The impact was assessed using the following parameters: average weight, absolute, average daily, and relative gain, mass accumulation coefficient, and relative growth rate. Feeding rates were calculated based on the feed manufacturer’s recommendations, and preparations containing the strains were sprayed onto the feed. Weighing was performed every 10 days. According to the results of the first experiment, high values of relative increase were shown by the groups of young sterlet fed with Enterococcus muntdii – 20.50 %, Lactobacillus plantarum – 16.61 % and the relative growth rate was Enterococcus muntdii – 1.55 %, Lactobacillus plantarum – 1.28 %. According to the results of the second experiment, the control group showed the lowest results in terms of average weight (123.2 ± 5.21), the highest values were in the experimental group using the strain 162 St – 130.58 ± 5.33, in the Bacillus licheniformis 2336 group – 128.31 ± 7.63. In terms of relative increase and relative growth rate, the experimental groups also outperformed the control. A conclusion was made about the need to study the isolated strains both with an increase in the observation period and with an analysis of hematological parameters, an analysis of the intestinal microbial community at the end of the studies.