Selenium and oxidative stress in shrimp - An interesting view.

Hello everyone:

        Today we will see about some of the interesting facts about selenium in shrimp. 

       Selenium is an important trace mineral which required for shrimp growth.          Optimum level required for vannamei is about 0.35-0.38 mg per kg of feed. 

Important functions:

       It plays an important role in the function of structural components. 

        It plays as a cofactor to form glutathione peroxidase and plays role in protecting biological membranes. 

        Low level of selenium in feed reduces growth and induce oxidative stress to the animal. 

Excess selenium also causes toxic effects due to excessive synthesis of seleno-sulfur amino acids. 

This amino acids may negatively affects the antioxidant enzymes functions.

Plant meal:

       If your diet have excess amount of plant meal nutritional source, then it may lowers bioavailability of trace elements in shrimp body. 

        Those phytic or phytate strongly chelate to essential minerals and made them insoluble. 

Other functions:

          Selenium also increases humoral activities in shrimp body. 

          Inorganic form of selenium affects HP of shrimp. 

These are the some of common and important functions of selenium in shrimp farmers. 

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Thanks and regards, 

P. Dhivagar BFSc, 

+91 9384346193.

Importance of functional feed supplements in shrimp farming.

Hello everyone:

         Today we will see about importance of functional feed supplements in shrimp farming. 

Risk factors:

     There are several risk factors associated in growth of shrimp. Easy susceptible to pathogens due to improper management, poor quality PL are the some of several risk factors in shrimp farming. 

    

Feed supplements:

       Various functional feed supplements are recommended for the better growth and performance of shrimp in early growth phase. The common supplements includes vitamin C and E which is essential vitamins which is not secreted by shrimp body. These supplements plays important role in increasing antioxidant activity, immune response, production of reactive oxygen species etc... 

      These supplements are must need in shrimp pond at certain stages particularly in nursery management. 

Beta-glucan:

      It is an another important compound which gives positive results on growth and immune response of the shrimp. When you are increasing feeding frequency, discontinuous feeding , this supplements increase immune response and regulating different growth factors in shrimp. 

Phytochemicals:

       These are non nutritive chemical compounds which have beneficial effects of maintaining shrimp gut microflora. These chemicals have antimicrobial activity and increasing the efficiency of probiotics in gut.

Methionine:

      Methionine and lysine are the essential amino acids which plays important role in innate immunity of the shrimp. 

      If your feed is formulated with more plant based meal then it will be deficient in some of essential amino acids like methionine and lysine. 

     At this time, supplementation of these supplements will impact on growth and immune response of shrimp. 

       These essential amino acids are the precursors of another amino acids which is required for the growth of shrimp. 

   In studies they mentioned about growth performance of shrimp with different functional supplements, some time it may not create any impact on growth of shrimp but it induces innate immunity, antioxidant activity, propenoloxidase activity, growth and survival. 

Give supplements when the need comes.. 

All the best for better crop😀. 

Thank you.... 

Kindly share and follow my page for more info.... 

P. Dhivagar BFSc, 

+91 9384346193

      

Acid sulphate soils in aquaculture.

Hello everyone:

Have you heard about this? 

Sudden death of fish at overnight after rain. It happened in many places. It is due to presence of acid sulphate soils. The toxicity which is produced under aerobic condition and diffusion from soil to water then cause sudden death of fish. 

Acid sulphate soils:

       These types of soils present in the regions of wetlands. Excess accumulation of organic sediments in bottom soil causes pyrite formation. Mostly occurs in mangrove areas and other wetlands. The root system in mangroves accumulates more organic matter. 

    It also formed in the area with more anaerobic condition. 

Before that, we have to know about different forms of iron. 

Iron generally present in Ferrous iron in anaerobic condition, when it is oxidized then changed into ferric iron and precipitates as a ferric hydroxides. 

In acid sulphate soils, sulphate gets reduced to sulphide and oxidation of sulphide to sulphur. 

What is present in acid -  sulphate soil? 

     The different components which gives rise to formation of acid-sulphate soils are Sulphate, iron, excess organic matter and anaerobic condition. 

    This is called as pyrite. 

Oxidation of pyrite:

 When the soil gets aerated then this process will happens. 

               Pyrite oxidation

                Acidic condition

                 Ferrous iron

        At low pH get oxidized to 

                    Ferric iron

            Reacts with sulphate

                 Ferric sulphate

Sulphuric acid also formed from the oxidation of element sulphur. 

This causes soil more acidic and not suitable for aquaculture and causes toxicity to animals. 

Iron, aluminium ions in the soils causes various toxicity. These ions make unavailable of essential minerals which is required for primary production in pond. 

Measures to take for treating acid-sulphate soils:

1. Try to avoid the site which have acid sulphate soils

2. Removal of subsoils with certain depth to reduce organic load in pond bottom. 

3. Application of minerals like calcium carbonate to neutralize the acidity. 

4. Drying and drain the ponds at regular intervals. 

5. Gets completely in oxidized zone. 

In this soil can be easily identified by testing soil pH and presence of yellow or reddish colour in the surface soils. 

Thank you.. 

Contact for more info.... 

P. Dhivagar BFSc, 

+91 9384346193