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How to Treat White Feces Disease (WFD) Shrimp Vannamei

How to Treat White Feces Disease (WFD) Shrimp Vannamei

In the world of shrimp farming, white feces disease (WFD) is an issue that is always hotly discussed when discussing shrimp disease. Understandably, until now, WFD is still a frightening specter for some of our shrimp farmers.

From the observations of practitioners, the WFD or white dung disease that often attacks shrimp is inseparable from the poor management of the pond's environment, both in terms of water quality and pond bottom.

image: viv.net

Poor pond water quality is characterized by low dissolved oxygen or DO values ​​and fluctuating acidity (pH) values. The poor quality of water cannot be separated from the poor quality of the pond's basic environment. As a result of excessive feeding, organic waste material that accumulates more and more. If left unchecked, the pH quality of the waters becomes poor.

Poor water quality with increasing organic water fertility has an impact on the life of plankton in pond waters. The explosion in the amount of plankton will obviously affect the level of dissolved oxygen in the water. At night, shrimp must compete with plankton to get dissolved oxygen. If there is mass death in plankton, we can be sure the quality of the pond water will get worse.

Do not stop there, the accumulation of organic waste at the bottom of the pond causes the number of Vibrio bacteria to increase. Conditions of minimal dissolved oxygen in pond waters also triggered the development of anaerobic bacteria, which are thought to be one of the culprits for the emergence of WFD.

Water Quality Management

Before being put into cultivation plots, visit to coinbazooka water from rivers or the sea must first be collected in a reservoir to be treated. While in the mini kola, the quality of the water is taken care of to match the quality needed for the shrimp to grow healthy.

To supply dissolved oxygen, the presence of a pinwheel is needed in a cultivation plot. Especially if the shrimp density in the pond is high. Waterwheel placement can also be done in reservoirs (treatment) if necessary to enrich the water with dissolved oxygen before entering the cultivation plot.

No less important, the water released from the cultivation plot must also be considered. Especially if there are many other ponds that take water from the same source. After harvesting, aquaculture water is first deposited before being released into the river, sea or reused.

Pond bottom management

A good pond has a special pond for collecting mud ponds. After harvesting, the organic sludge is dredged and thrown into the special mud pond. Pond sludge from aquaculture plots should not be disposed of around maintenance plots. It is feared that it could become a path for the spread of disease-causing bacteria to other cultivation plots.
By implementing water and mud management at the bottom of the pond, the process of preventing the emergence of WFD can proceed in a sustainable manner. Not only improving the quality of cultivation in the pond itself, this method also has a positive impact collectively.

How to prevent this can also be applied in various business segments of the pond. In the application of pond water recirculation, this prevention method can be applied, both with monoculture and polyculture commodities with fish. Similarly, ponds that still apply conventional techniques.

The danger of H2S (Hydrogen Sulfide) on the pond Ecosystem

The danger of H2S on the pond Ecosystem

H2S (hydrogen sulfide) is a toxic gas that is colorless, flammable and smelly like a rotten egg. H2S emerges from biological activity when bacteria deflated organic substances in a state without oxygen (anaerobic), such as in swamps and sewage drains. H2S is formed from the process of decomposition of organic substances by bacteria. Therefore, H2S is found in oil and gas, gutters, flooded water, such as marshes and also formed in other industrial processes and biological processes. 

Characteristics of H2S:

  1. Highly toxic and deadly
  2. Colorless
  3. Heavier than air so it tends to gather and dwell on low areas 
  4. can be burned with blue flames and the result of combustion (sulfur dioxide gas – SO2) is also a toxic gas
  5. Highly corrosive, resulting in rust in certain metals 
  6. at low concentrations, it smells like a rotten egg and can paralyze the senses of human smell
H2S is one of the toxic compounds found in the base sediment that is anoxic (no oxygen/anaerobic). Although it is toxic to shrimp and fish, it will always be at the base of the Anoxyc pond, but the appearance is still often overlooked. 


In short, H2S is formed from:

Residual or exiles from the process of decomposition of organic materials, such as the rest of the feed, carcass/fish and plankton that are located at the base of the pond. The sulfate reduction process (SO42) by the sulfur-reducing bacteria group. H2S is generally toxic to most bacteria, but there is a group of certain bacteria that can use H2S as a source of energy growth. Photosynthetic anoxygenic bacteria (BFA) such as Rhodobacter, Rhodopseudomonas, Rhodospirillum, and others as well as chemolitotrof bacteria will oxidize H2S into sulfite (SO32-) and subsequent sulfites are converted into sulfates (SO42) that are not Toxic. 

Because of its formation without oxygen, he H2S will only be found in the mud base of the pond/near the border between the mud and pond water surfaces. If water and mud at the base of the pond are piqued due to water currents, activities siphon or when the animal eats above the mud, then it is likely that H2S will contact with shrimp/fish and cause the condition of H2S poisoning. If you smell a foul egg when the deposition at the base of the pond is dismantled, it is an indication of anaerobic conditions and the presence of H2S gas. Practically, if we are able to smell the rotten egg from the mud of the pond, then it is worth approximately 0.0047 ppm. The concentration of H2S is ideal to be in a pond is 0 (zero). 

The threat of H2S for aquatic animals is damage to gills, stress, and death. If the animal is exposed to H2S in medium and long periods of time, symptoms that may arise are reduced appetite, slow growth, increased vulnerability to the attack of other diseases and parasites, until the occurrence of Increased mortality. 

The existence of H2S in ponds is influenced by pH, temperature and DO levels. The highest toxicity of H2S is at pH < 6.5. Shrimp farms generally have a pH range of 7 – 9, but we should be wary if at any time there is a decrease in pH caused by algae respiration especially in the early morning. Contrary to pH, the toxicity of H2S increases in high temperatures and conversely, high DO will lower the toxicity of H2S because the presence of oxygen can turn H2S into non-toxic forms of ions. 

It is worth remembering that the H2S formation process is part of the Sulfur cycle that will continue to occur in the pond. The best way to overcome H2S is to prevent the accumulation of toxic gases in the base of the pond, namely by adding the probiotic Bacillus subtilis that serves as the decomposition of organic matter, as well as thiobacillus. These bacteria work by means of the oxidation-reduction reaction system on sulfur compounds. Some of Thio species are recommended for the prevention of H2S:

  • Thiobacillus denitrificans
Serves to neutralize H2S and Nitrit through denitrification reaction
  • Thiobacillus Ferooxidans
Can neutralize H2S toxins and oxidize iron ions that inhibit respiration and growth of shrimp

  • Thiobacillus thiooxidans
Serves to oxidize the sulfur compounds into nontoxic compounds and stabilize water
  • Thiobacillus Novellus
Can neutralize the poison of H2S in the basic environment of very acidic ponds on peatlands and pyrite.

History of White Feces Disease and How to Handle it

History of White Feces Disease and How to Handle it

In early 2010, tempted by the high price of shrimp, many shrimp farmers in Thailand decided to increase stocking density to achieve high levels of production. Therefore, an increase in water temperature (> 32oC) and an increase in the amount of feed given, resulting in increased levels of organic matter at the bottom of the pond. High levels of organic matter at the bottom of the pond cause the emergence of new pathologies namely Vibrio parahaemolyticus (green colony), V. fluvialis (yellow colony), V. vulnificus (green colony), V. mimicus (green colony), V. alginolyticus and V. cholera. The six types of pathogenic vibrio are allegedly the cause of the emergence of WFD disease or often referred to as white feces disease.

This disease was first detected in Penaeus Monodon, which is cultivated in waters with low salinity, but then spread to all shrimp production areas in Thailand, where to date 99% have switched to Litopenaeus Vannamei cultivation.

From the results of subsequent analyses, Gregarine was found in shrimp feces. Gregarine is a Nemaptosis sp. Gregarine is an endoparasite found in shrimp midget. This protozoan is mostly observed in the trophozoite stage (an active form of protozoa that can invade tissues). Damage caused by Gregarine is minor, but if in large conditions it can cause damage to the stomach edge and become an intermediary for bacterial infections.

DISEASE SCENARIO


This disease occurs in pond bottom quality that is different from normal conditions, which results in deteriorating water quality. Peak death rates are seen at very low oxygen levels (3.0 mg / l) and also low levels of alkalinity (<80 ppm).

An early indication of this disease is the appearance of white stools (like a thread) that float on the surface of the water and anco.

White Feces Shrimp floats on the surface of the water





Characteristic of viruses

Clinical symptoms that can be observed include Blackish color changes in the gills caused by the presence of epibiotic protozoa, loose shells and shrinkage of the hepatopancreas. The intestine is not filled with food but there are strands of white feces. Sometimes white stool (2-3 cm long) can be seen on the diseased tail of the shrimp. Besides contracting, the hepatopancreas also changes color to blue and white. (Figure 2)

WFD can have an impact on shrimp in the form of decreased appetite, stunted growth, and chronic death. Feed conversion (FCR) also reported an increase of 2-3 compared to healthy shrimp ranging from 1.4 to 1.7.

Physical shrimp infected with White Feces Disease (WFD)

























Some things that can be done to prevent WFD include:



  1. Control of feed program
  2. Good management of pond bottom and DO
  3. Addition of organic acids to feed
  4. Adding probiotics to clean pond bottom
  5. Giving immunostimulant in feed

The addition of organic acids (Acetic Acid, Formic Acid, Lactic Acid, and Propionate Acid) of 10 ml/kg of feed and probiotics were allegedly able to help prevent shrimp from WFD infection. Organic acids are recommended to be added to the feed is in liquid form, because it is more easily seep into the feed.

Hepatopancreatic Microsporidiosis (HPM) or Enterocytozoon Hepatopenaei (EHP) Vannamei Aquaculture

Hepatopancreatic Microsporidiosis (HPM) or Enterocytozoon Hepatopenaei (EHP) Vannamei Aquaculture

Enterocytozoon Hepatopenaei (EHP) is a microsporidia disease that first occurred in P. monodon tiger shrimp in Malaysia in 1989. EHP can spread directly through cannibalism but does not trigger White Feces Syndrome (WFS), EHP can also be found in shrimp infected with WFS. Chances are EHP is a trigger factor for WFS. EHP transmission can also be through Polychaeta and mollusks (mollusks) but it is not yet known whether they can act as carriers or not. Crabs can also be a source of transmission for shrimp. Transmission of EHP does not require hosts. Until now the prevalence of EHP is unknown. Studies from the Central Institute of Brackishwater Aquaculture (CIBA) indicate the incidence of EHP around 15.6% of 100 farmers. Around 16% of them were detected as having slowed growth and 50% were experiencing WFS. Mortality caused by EHP is quite varied, reports from farmers show 1-2% of daily mortality.

This parasitic EHP infection is also widely associated with White Feces Syndrome (WFD-White Feces Disease). Shrimp infected with EHP will be blackened and small in size. This parasite infects hepatopancreas tubular epithelial cells from shrimp connective tissue. Then limit the number of nutrients that can be absorbed by the hepatopancreas. As a result, shrimp become starved so that slowing growth occurs.

The microscopic picture that is seen is a change in color like milk in the muscles due to microsporidia collection. Therefore this disease is also called "cotton shrimp disease" or cotton shrimp disease.

EHP Virus









virus prevention methods

Prevention of EHP at the stage of seeding and enlargement is to not use live animals (Polychaeta and mollusks) as food. Whereas for ponds, the following two things can be done to control EHP: First, use seeds that are free from EHP. Second, pond preparation is good, especially in ponds that have experienced EHP, EHP spores have thick walls and are not easily activated even by using chlorine in high doses. In ponds that are still based on land, they can use CaO during the period of re-preparation of pond land. Because EHP is a parasite that forms spores, water disinfection can be an important consideration in preparation for ponds that have never experienced EHP.

The importance of micro mineral content in Vannamei shrimp feed which is maintained at low salinity


img: psmag.com

The importance of micro mineral content in Vannamei shrimp feed which is maintained at low salinity

In shrimp farming, especially in environments with low salinity content usually has a low mineral content as well. Low minerals in water can cause shrimp growth to be slower. This is because shrimp has the ability to absorb some inorganic elements not only from food but also from the environment. However, due to the low mineral content in the environment, shrimp growth was hampered.

Minerals are one component that is needed by living things besides carbohydrates, fats, proteins, and vitamins. Minerals needed by shrimp are very few but have a very important function. The amount ranges from 2-5% of the total amount of raw material. The types of minerals needed by the body are divided into two, the minerals needed in large quantities are called macro mineral elements, while in small amounts they are called micro elemental minerals.

Micro mineral elements have a big role in shrimp nutrition along with other minerals for shrimp health and better production. The types of mineral microelements are Cobalt (Co), Copper (Cu), Iodine (I), Ferrum (Fe), Manganese (Mn), Nickle (Ni), Fluorine (F), Chrom (Cr), Selenium (Se ) and Zinc (Zn). These micro-minerals are involved in the process of cell metabolism, skeletal structure formation, maintenance of the colloidal system, acid-base regulation, immunity to disease and other physiological functions.

The function of each mineral specifically is:


  • Cobalt: As a component of cyanocobalamin (B12) which is very much needed for the synthesis of microflora in the intestinal tract and for the formation of red blood cells and treatment of nerve tissue.
  • Copper: For normal growth and health. Helps in the protection of the bones, nervous and cardiovascular systems. It is a powerful antioxidant, works with antioxidant enzymes, superoxide dismutase to protect cell membranes from free radicals.
  • Iodine: Regulates the metabolic rate of all processes into the body and is a key element of thyroxine and regulation of oxygen use.
  • Ferrum: Involved in the transport of oxygen in the blood and the transfer/transfer of electrons in the body. A very important element of the enzyme system variation, which includes the enzyme catalase, peroxidase enzyme, xanthine oxidase enzyme, aldehyde oxidase enzyme, and succinic dehydrogenase enzyme.
  • Manganese: As a cofactor for arginase and metabolic enzymes, as an activator enzyme for enzymes that bridge the movement of the phosphatase group, and as bone-forming, carbohydrate metabolism and reproduction cycle.
  • Selenium: Protects cells from the effects of peroxidase and together with vitamin E as an antioxidant that protects polyunsaturated phospholipids in cells and sub-cell membranes from peroxidative damage.
  • Zinc: As a cofactor of several enzyme systems that are important in metabolic processes and as essential for the structure and function of insulin.

If several minerals such as Zn, Mn, Cu, and Se are combined have a special role in animal immunity by increasing the immunity system of the farmed animal. While the incorporation of minerals Fe, Cu, and Ca plays a major role in the respiratory process. This mineral will help the metabolic process including all minerals, both essential and non-essential.

Factors To Look For In Freshwater Lobster Cultivation

img: abc.net

Factors To Look For In Freshwater Lobster Cultivation

Lobster is a high protein food commodity that comes from North America. In Indonesia alone, lobster has many fans because of its thick meat and high nutritional content. In the process of shrimp farming, there are several factors that you need to consider, namely:

The main requirement for life


Lobsters that live in freshwater have slightly different living conditions than seawater shrimp. In general, LAT shrimp are more tolerant of very low dissolved oxygen levels. This type of shrimp also requires clean air circulation which can be created by aerator installation.

Temperature

In general, lobsters have a very high level of resistance at extreme temperature changes. This organism can live in temperatures over 35 oC, but lobsters can also live under 00C. For shrimp that are bred in freshwater, the optimum temperature required to provide a quality crop is 25-29 oC.
pH

During its development, the pH of the water needed is in the base range and to make it, you need lime content high enough so that dissolved calcium for shell nutrition is met. With the right pH, the weight of the lobster harvested can be more than 25kg in the expected period.
Aquaculture water quality

The next thing to think about is the issue of aquaculture water quality. When filling water in a pond, you need to understand that LAT is quite sensitive to oil residues. Besides, young LAT is also less resistant to high chlorine levels. That's why before you decide on LAT nurseries, you need to ensure water quality first by checking the presence or absence of contaminant metal compounds mixed in the water.

Technical business

When you want a satisfying LAT crop, you need to understand the technical effort that must be done. This business technique is the key lies in the breeding process that requires a lobster parent measuring above 2 inches. The following are the steps that need to be carried out during lobster breeding.

Provide a special pool that is used for breeding ponds (fertilization). Generally in 1 m2 prepared 5 females and 3 males
Ensuring that in 1m2 breeding ponds 10 animals are reared in separate male and female ponds.

Type of feed

In the enlargement process, certain foods contain protein, minerals, vitamins, and high carbohydrates. The type of feed chosen must have a high level of solubility in water so that shrimp will not be easily attacked by pests. Both natural and artificial feed provided, the concentration of feed should not exceed 3% of the total body weight of LAT. Feed must also be given every morning and evening at the same time.

Pest Control

In the process of breeding, lobsters also need to be maintained health so that the harvest is abundant. Here are some types of diseases that you need to be aware of during lobster farming

Crayfish plague, the transmission of this disease can occur from equipment owned. The cause of this disease is generally a virus or fungus that makes shrimp endurance decrease. To avoid this, you need to pay attention to the cleanliness of the pool and replace the water regularly.
WSD. White spot disease is a disease that often affects lobsters in ponds. When there is one shrimp that is infected with this disease, certainly, other shrimp in the same pond will immediately die. To avoid diseases caused by this virus, you must always maintain the acidity of the water and clean the tool that is infected with the virus

3 Ways to Reduce Fe Levels in Water




3 Ways to Reduce Fe Levels in Water

The Fe content is too high to be a reference that the water is not good water, especially in the aquaculture process. In shrimp farming, excess Fe content can cause shrimp to experience environmental stress and eventually die.

There are 3 ways that can be done to reduce levels of Fe in water, the three ways are aeration, sedimentation, and filtration The following is an explanation of the three ways:

1. Aeration

Aeration is the process of flowing air into water. Oxygen flowing is known to reduce Fe levels in the water. In the process of shrimp farming, aeration is usually done with the help of a waterwheel. For this reason, by increasing the use of waterwheels, the levels of Fe in ponds can be overcome.

2. Sedimentation

Sedimentation is the process of settling solid particles suspended in water aided by Earth's gravity. In principle, this sedimentation process serves to reduce chemicals that are heavier than water at the bottom, so that they can be removed easily. Sedimentation is relatively inexpensive because it does not require special equipment or the addition of other chemicals.

3. Filters

Filtration is the process of filtering water that contains Fe so that the water becomes cleaner. The most common material used for filtering media is sand because it has a high filter power and has long durability and can be used repeatedly.

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How to Treat White Feces Disease (WFD) Shrimp Vannamei

How to Treat White Feces Disease (WFD) Shrimp Vannamei In the world of shrimp farming, white feces disease (WFD) is an issue that is always...