Shrimps have no immune system that would allow to vaccine them, but they have, as superior vertebrates, a non specific defence line, more efficient than antibodies.
They produce superoxide dismutase enzymes SOD, which are the first cellular defence line against various metabolic dysfunctions (stress, diseases) resulting in free radicals accumulation.
In shrimps, SOD are so important that there are reference proteins, which are measured in order to evaluate other immunostimulants’ efficiency.

The diseases met in shrimp aquaculture mainly results from a lack of immune defences, weakening these aquatic organisms by different ways:
- Breathing difficulties at any age, the younger they are, the more vulnerable they are, even in the low density soil pools.
- Nutriment absorption difficulties because of less efficient digestive enzymes, resulting in growth and reproduction falling off.
- Essential oligoelements and vitamins assimilation difficulties when they are no more in a ionized usable form.
- Decrease of response ability to stress and growing pathogenic risks.

That is why SOD is an inescapable enzyme in shrimps.

• Superoxide dismutase
We breathe oxigen to live, which is used by our cells to produce energy. But energy production goes with a low emission of toxic product, as a fire generates smoke. The toxic product is the superoxide anion. It is formed by the addition of one electron, negative electric charge, on molecular oxygen.
The Superoxide dismutase is a natural enzyme of the organism, able to neutralise superoxide anion very quickly.

• Free radicals
These chimical species, produced in our organism, have an odd number of electrons on the external orbital, as the superoxide anion. It gives them the property to react with other molecules by giving them the electron. That is what happens when iron rusts: it gives to air oxygen electrons.
That is why living organisms’ cells rust little by little with ageing, but also strongly in acute diseases or gradually in chronic diseases. Oxygen free radicals are called oxidants for that reason.

• Oxidative stress
Life is like a permanent burning fire. It produces more or less heat for our happiness and let a bit smoke escape, canalized by a good draught of the systems we use. When fire is no more under control, it can either burn everything or suffocate by excessive smoke production. Oxygen free radicals production, the oxidants of the organism, is canalized by the antioxidants’ action. A balance establishes just as in a heartily burning fireplace.
When this balance is disrupted, it is called oxidative stress.


• Enzyme
Numerous chemical reactions are quickened by miscellaneous substances. They are called catalysts. The proteins naturally produced in the living organism and having this property are biological catalysts, called enzymes.
Thus, superoxide anion is naturally knocked down slowly and partially, what gives it time to react with other molecules, causing considerable damage. In the presence of the superoxide dismutase enzyme, superoxide anion is eliminated 10 000 times faster!

• Antioxidant
These molecules are able to neutralize free radicals and to regulate their production. In the best of all possibilities, a balance sets up between oxidants and antioxidants.
The SOD, superoxide dismutase, is a major antioxidant enzyme, the anti-rust enzyme of the organism’s cells.