Immunochemical response and gene expression in juvenile shrimp (Litopenaeus vannamei) exposed to microorganisms isolated from marine sediment

Abstract

The use of microorganisms isolated from the natural environment can improve the culture conditions in aquaculture systems and the immune and antioxidant response capacity of cultured organisms. In this study, the immunochemical response and gene expression of Litopenaeus vannamei juveniles were analyzed following exposure to microorganisms isolated from marine sediments after in vitro characterization of their probiotic properties. Two yeasts and one bacterium strain were used by immersion method (48 to 216 h) at a concentration of 1 x 10(6) CFU/mL with the following treatments: (1) Control, without probiotics; (2) Positive Control, commercial immunostimulant (Laminarin; beta-1,3, glucan); (3) Candida maris , strain A1; (4) Geotrichum candidum , strain A3; and (5) Curtobacterium sp., strain S13. Shrimp treated with microorganisms and commercial immunostimulants showed a significant increase (P < 0.0500) in the soluble protein content in hemocytes compared with the control group. At 72 h post-exposure (hpe), G. candidum , Curtobacterium sp., and laminarin treatments showed a significant increase (P < 0.0500) in superoxide desmutase (SOD) activity compared with the control group. SOD enzyme gene expression showed a significant increase (P < 0.0500) in all shrimp treated with microorganisms from 48 hpe. The results obtained showed that the use of three microorganisms isolated from a marine environment can stimulate the protein content in circulating hemocytes, antioxidant activity, and gene expression in juvenile L. vannamei .