Improving the aquatic organisms immune resistance with probiotics for the aquaculture sustainable development

Abstract One of the ways to strengthen the immunity of animals in aquaculture is the use of immunomodulators as a food supplement. This work presents a study on the effect of the probiotics Bacillus subtilis and Bacillus licheniformis on the immunity of crayfish and fish. It was found that the use of the probiotic “Subtilis-C” as a feed supplement strengthened the immunity of narrow-clawed crayfish: the survival rate increased almost threefold in the presence of Saprolegnia parasitica in the water and the incidence of burn-spot disease (BSD) decreased. The average cytochemical coefficient (ACC) of the lysosomal cationic protein in hemocytes decreased. It appears that crayfish consume this cytotoxic protein for immune protection. In carp fed with the probiotic, the immunity to saprolegniosis was strengthened, the body weight gain increased significantly, the amount of hemoglobin increased by 15%, and the number of erythorocytes in the blood almost doubled. An increase in metamyelocytes was noted in WBC differential count of these fish.