Assessment of hematological parameters of rainbow trout when probiotic preparations are introduced into the diet

Increasing aquaculture production is an important condition for ensuring food security in Russia and promoting socio-economic development of the regions. Parasalmo mykiss or rainbow trout is one of the most popular objects of industrial fish farming due to its commercial value and biological characteristics, including rapid growth and resistance to intensive cultivation conditions. The purpose of this study was to examine the morphological parameters of rainbow trout (Parasalmo mykiss) blood when introducing various probiotic preparations into the diet. To assess the physiological state of the fish, the following morphological parameters of blood were determined: the number of erythrocytes and leukocytes, hemoglobin concentration, hematocrit. When analyzing the data obtained from the use of the probiotic supplements Probiotic-1 and Probiotic-2 in the diet of yearling rainbow trout, it can be concluded that the average erythrocyte count of yearling trout, whose diet included the supplement Probiotic-2, is 30.7% higher than that of the group receiving the production feed without additives, and 13.74% higher than that of the group receiving the supplement Probiotic-1 with their feed. The total leukocyte count of yearling trout, whose diet included the supplement Probiotic-2, is 3.11% higher than that of the group receiving the production feed without additives, and 1.39% higher than that of the group receiving the supplement Probiotic-1. Thus, it can be concluded that the experimental probiotic preparations based on bacterial strains of the genus P. Lactobacillus on morphological parameters of rainbow trout (Parasalmo mykiss) blood. These preparations have an adaptogenic effect on the rainbow trout organism, contributing to an increase in resistance parameters. The obtained results can be used to optimize the composition of production feeds for rainbow trout and to correct the microbiome of fish of different ages.

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