Application and effect of lactic acid probiotic bacteria in the blue crab Callinectes arcuatus under laboratory conditions.

To avoid losses by viral and bacterial diseases in organisms of aquaculture importance is the use of probiotics. Lactic acid bacteria have shown to improve growth and immune response in crustaceans. The present work aimed to isolate, biochemically and molecularly characterize free and microencapsulated LAB strains (ion gelation) and evaluate the effect on growth, survival and immune system of the blue crab C. arcuatus. A total of 45 presumptive LAB strains were isolated from the intestine of C. bellicosus. Only two of them showed gamma hemolysis (A2-2 y A2-4b), were Gram-negative, cocci, with hydrophobicity, autoaggregation and medium biofilm formation and had a 99% similarity to Pediococcus pentosaceus. The strains were microencapsulated with a viability of 42.6% (A2-2) and 5.8% (A2-4b) for 90 days of shelf life. In the in vitro release, it was observed that the highest percentage occurred in the intestine extract where LAB were microencapsulated (95.00 ± 0.45%) and as for the effect of microcapsules of P. pentosaceus (A2-2 and A2-4b) added in the diet, it was observed that in the SGR, T V presented the highest daily growth compared to the control (without microcapsules) and other treatments (P < 0.05); the highest survival was presented in T V (83 ± 3.33%) (P < 0.05). In the immune response, an increase in the number of hemocytes was observed, while the values of superoxide anion, poPro and PO were minimal in the treatments with microencapsulated LAB, with a frequency of application every 2 days in the food.