Importance of minerals during moulting of shrimp.

Hello everyone:
    Today we will see about importance of minerals during moulting of shrimp.

What is moulting and why it happens:
       Moulting is nothing but a process which related to growth of the shrimp. In this process old exoskeleton is removed(ecdysis) and new exoskeleton will be formed. If moulting occurs means,it refers to the body size of the shrimp increases,(some moulting occurs due to osmotic shock or any other changes happened in water quality, these type does not increases the body size). 
             Moulting - body size increases

Different stages in moulting:

Premoult - It is divided into some substages like D,D1,D2,D3,and D4.
Premoulting is the stage , this stage denotes that shrimp is preparing for the moulting process. In premoulting large amount of nutrient reserve is accumulated in the body. This energy used for moulting process. 
D,D1- Moulting hormones are produces for induce the moulting.
D2- decreased feed intake and decreased osmoregulatory process.
D3 and D4- feeding stopped and water uptake is high, nutrient reserve also depleted.
After D4, ecdysis happens, it will takes from few seconds to few minutes. ( Good maintenance of pond ecosystem gives better results of moulting).

Post moult:
It occurs after ecdysis process. In this stage shrimp absorbs excess of water to form new exoskeleton in the body. At this time we have to give proper minerals to the pond. Because shrimp absorbs minerals from the water directly. If minerals present in optimum rate means, the formation of exoskeleton is fast. After absorbing the water from pond , the shrimp hardens it newly formed exoskeleton. For this process also proper nutrient is required by shrimp to complete the process.

Absorbs water - new exoskeleton - proper minerals- hardens the shell.

Two substages: A and B.
After ecdysis the first stage is A, in this stage shrimp body is very soft and there is lot of possibilities for infection and cannibalism. We have to maintain proper ammonia, nitrite and pH in the pond to regulate the moulting process.
Alkalinity also plays important role in Moulting. Alkalinity maintains pH . At the time of moulting there is possibility of reducing alkalinity, because shrimp absorbs minerals like calcium that is present in water. So we have to maintain alkalinity.

Next stage in postmoult is B - it is the later stage of postmoult. From this stage shrimp increases  the feed intake.
Stage A - very soft body - maintain alkalinity.
Stage B - increases feed intake.

Intermoult: It is stage between postmoult and premoult.( Period between postmoult to next premoult). In this stage tissue gaining occurs by replacement of water which is absorbed during Moulting process. Feed intake is high and nutrients are stored.
Intermoult - tissue gains in body.
Don't confuse ( intermoult occurs between postmoult and premoult. Not occurs between premoult and postmoult)

Minerals:
   Calcium, magnesium, phosphorus, potassium are the some of key minerals which is mostly required during moulting process. 
   Proper minerals supply prevents osmotic shocks during moulting.
   If minerals is declined means , it causes soft shells and getting easy chance for infection.
   Freshwater or low saline water requires high amount of minerals during Moulting compared to high saline water.

 If you saw moulting in your pond.. then do the following things.
 
Apply EDTA in your pond to reduce excess of irons and others toxic metals which is present in your pond. EDTA reduces hardness of the pond and promotes Moulting.
Then...
 Reduce feed , because shrimp does not take feed at stages from D2 to A. by reducing the feed we can reduce the wastage of feed in your pond.
Then...
 Immediately apply minerals in your pond for fastening the moulting process and new exoskeleton formation.
Then...
  Already told,there is chance for reducing alkalinity in your water at moulting process , so you have maintain alkalinity by adding sodium bicarbonate or lime or dolomite in your pond. After completion of moulting again we increase the feeding.

Intervals between the moulting depends on the weight of shrimp.
Post larvae - daily Moulting.
If 5 gm weight - moulting in 7-8 days once.
Premoult (D,D1) - 4-5 days ( excess nutrients accumulated)
D2- ecdysis - max 1 day( no feed taken).
Post moult ( A-B) - half a day ( absorbing water and minerals required.)
Intermoult- 2 days( muscle gaining) 
.......
Next...
Premoult comes.... Postmoult.... intermoult..
Researches told that vannamei sp, Mostly moulted in new moon time . After moulting shrimp wants to hide itself to escape from cannibalism. New moon means dark , so at that night time of new moon extra dark occurs , it favours for shrimp moulting and hiding. But also based on the body weight ,the Moulting process occurs. But there is disadvantage due to various sizes in populations of cultured shrimp. If we overcome this, we can get good results.

Observe moulting- reduce feed - save feed.

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