Background:

Lectins act in plants and animals as recognition units against invasive pathogens, participate by activating the immune system, and function as recognition mediators of immune response in invertebrates. Few studies have evaluated the effect of immunostimulants on the activation of lectins in crustaceans.

Goals:

To evaluate the lectin concentration in juvenile shrimp treated with commercial and microbial immunostimulants.

Methods:

Five treatments were added directly to the culture tanks every third day during 12 days: 1) laminarin (0.5 mg ml-1); 2) mix 1 (Bacillus tequilensis and B. licheniformis; 2x106 CFU ml-1, 1:1 proportion); 3) mix 2 (B. endophyticus, strain YC3-B and strain C2-2; 2x106 CFU ml-1, proportion 1:1); 4) Debaryomyces hansenii (1x106 CFU ml-1); 5) control (without immunostimulants). At day 12, after the last treatments were added, samples of hemolymph were extracted from shrimp at 24, 48, and 72 h to determine lectin concentration by the ELISA method, using monoclonal antibodies against Macrobrachium rosenbergii lectin (MrL).

Results:

Significant differences (p <0.05) in the lectin concentration were found in shrimp groups treated with laminarin at 24 h after the last exposure to the treatment, followed by mix 1 and mix 2 at 72 h after exposure to the treatments. At 48 h, treatments did not register significant differences (p >0.05) when compared to the control groups. Shrimp exposed to D. hansenii did not show significant increase in lectin concentration compared to the control groups.

Conclusions:

This study showed that lectin concentration may be increased in plasma of juvenile shrimp and used as a bioindicator tool of immunostimulation.