CATDOLL : CATDOLL: What should we do if two diseases occur in shrimp at the same time? How to prevent and treat shrimp enteritis?

1. What should we do if two diseases occur in shrimp at the same time? How to prevent and treat shrimp enteritis?

If two or more diseases are found in shrimp at the same time, the primary and secondary contradictions should be identified and treated in sequence. A combination of oral and topical treatment measures can also be adopted.

If the shrimps in the breeding pond suffer from both ciliate disease and enteritis, a specific analysis is needed. If the shrimps suffering from enteritis are in the majority and the ciliate disease is not serious, the enteritis should be treated first. It can also be treated simultaneously through oral and topical administration.

Prevent and treat shrimp enteritis.

The pathogen is a member of the genus Vibrio or Aeromonas. The disease is mainly caused by infection with Aeromonas hydrophila.

The symptoms are red digestive tract, stomach of some shrimps are also red, mid-intestine is red and swollen, rectum is turbid and unclear. Sick shrimps are less active, lose appetite, grow slowly, but no dead shrimps are found. Prevention and treatment methods are the same as those for red leg disease of shrimps.

This article is from: China Agriculture Press "Green Development and Green Plant Protection"

2. Antibiotic-free experts | What harm will enteritis cause to shrimp? How to prevent it?

Microscopic examination of the intestines of these shrimps in the ponds revealed that most of them had enteritis, with intestinal pigments significantly diffused, blurred, or even red. What exactly causes enteritis in shrimps? And what are the solutions?

Causes of enteritis

Enteritis is a common disease in shrimp farming and can occur throughout the entire farming cycle. Generally speaking, enteritis is mainly caused by the following reasons:

1. Bacterial infection.

In recent years, outbreaks of shrimp diseases are mainly caused by bacterial diseases. Aeromonas hydrophila, Escherichia coli, Salmonella and other pathogenic bacteria are generally believed to cause enteritis in shrimp. When these pathogens dominate the intestinal flora, enteritis will occur.

Therefore, before being infected with pathogens, it is necessary to build beneficial intestinal flora in advance to compete and inhibit each other and maintain a stable dynamic balance. Many farmers have verified that adding pepper extract to the feed makes the shrimp intestine healthier and less likely to get sick.

2. Algal toxins

According to frontline observations, after the appearance of harmful algae in the pond, shrimps are likely to develop enteritis. However, when harmful algae dominate the pond, shrimps may be poisoned and enteritis may be induced due to flocculation or adhesion to feed, or the algae die and release algal toxins into the water.

Symptoms

When enteritis occurs, the digestive tract of the shrimp appears red, with the stomach being the most obvious. The posterior part of the intestine also becomes red or swollen, and the posterior cecum becomes turbid.

When the condition worsens further, the intestines will be broken and there will be stool dragging. The diseased shrimps will have poor vitality, slow feed intake and slow growth.

In severe cases, there is no food in the intestine, the intestinal mucosa necrotizes and falls off, pus or fluid accumulates in the intestine, the toughness of the intestine becomes poor, it is easy to break, and a small number of shrimps die.

Farming problems caused by enteritis

Slow growth, weak constitution

After enteritis occurs, the intestinal absorption capacity of feed nutrients decreases, resulting in malnutrition of shrimps, weight loss, difficulty in molting, and slow growth. Over time, the physical fitness and disease resistance will be greatly reduced, and the shrimps will die or suffer from other diseases.

Rapid deterioration of water quality

After the feed is ground in the stomach and digested by the liver and pancreas, it needs to be further digested and absorbed in the intestines. After shrimp enteritis, the intestinal digestion and absorption are less, and a large number of particles and soluble proteins that need to be further digested are directly discharged into the water, which is difficult to collect and discharge, and the water deteriorates rapidly.

Key points of prevention program

1. Slow feeding and feeding feed additives

When the weather is good, add feed steadily and feed the shrimps with chili extract for a long time. Experimental studies have found that chili extract has obvious appetite attracting properties and can significantly improve the body color of shrimps. Capsaicin, as an antibacterial active ingredient from natural plants, has a broad-spectrum antibacterial effect, can effectively fight against inflammation, reduce the occurrence of inflammation such as enteritis, and promote the healthy growth of animals.

2. Less stress, more repair

During the breeding process, stress and injury often occur, especially in high-density breeding in high-position ponds. On the one hand, try to avoid stress, such as water temperature changes, algae collapse, etc., and stabilize the water quality. Use natural pepper extract to improve the anti-stress ability and immunity of aquatic animals.

In short, chili extract is used for intestinal care of white shrimp. It is natural, green, safe, non-toxic, non-irritating, and has no drug residue. Practice has shown that when chili extract is mixed with feed in white shrimp farming, the shrimp's intestines develop stronger and fuller, the shrimp eats better, and the immunity is stronger.

If you have such problems in breeding, please send me a private message~

3. Aeromonas hydrophila

Aeromonas hydrophila is a common bacterium widely distributed in water bodies and other environments. Since the late 1980s, Aeromonas hydrophila septicemia has been prevalent on a large scale in my country's freshwater aquaculture industry, causing huge economic losses. This project systematically studied the biological characteristics and pathogenic effects of the main virulence factors of the bacterium, such as exotoxins, proteases, S layers, outer membrane proteins, and fimbriae, and established detection methods. The following viewpoint was proposed and theoretically explained: Whether bacteria are pathogenic depends mainly on virulence factors, that is, on internal factors, which has been generally recognized by peers. The correct breakthrough point has been chosen for this type of research.

Tilapia ulcer disease

The pathogen is Aeromonas hydrophila, a conditional pathogen that is ubiquitous throughout the entire breeding period and in the waters. However, it can only cause disease in tilapia under high-density breeding conditions and improper feeding and management. The body surface of the diseased fish is congested, and the surrounding scales loosen and fall off. It gradually ulcerates into blood-red, patchy depressions. The lesions have no specific location and may occur in all parts of the body, such as the head and trunk. When the diseased fish is dissected, it can be found that the liver is brown and the gallbladder is enlarged and dark green.

Prevention of tilapia ulcer disease: Use appropriate stocking density, enter the greenhouse in time to prevent frostbite, regularly use disinfectants such as dibromodimethoate and bromochlorodimethoate for disinfection, and feed fish with fish-bide, sea treasure and other feed baits. Feed some green feed appropriately to improve the immunity of the fish. After the disease occurs, remove the sick fish in time and move them to good water for temporary treatment. At the same time, sprinkle bromochlorodimethoate 0.3ppm or fish-bide 2ppm in the pond for water disinfection, and try not to use strong irritating drugs to avoid further irritation of the lesions. While using external medications, take fish nicotinic acid (0.15%) for 5 to 7 days.

4. Is Aeromonas hydrophila deadly to humans?

Aeromonas hydrophila is widely distributed in various water bodies in nature and is a primary pathogen of many aquatic animals. The bacterium belongs to the genus Aeromonas of the Vibrio family. It is a Gram-negative short rod with an extreme single flagellum, no spores and capsules. The pathogens just separated from the lesions are often connected in pairs. The colonies formed by culture on ordinary agar plate culture medium are round in shape, with smooth edges, a raised center, flesh-colored, off-white or slightly pink and shiny, and well-developed.

Aeromonas hydrophila can reproduce in water temperatures ranging from 14.0 to 40.5°C, with an optimum temperature of 28.0 to 30.0°C. It can grow in water with a pH value of 6 to 11, with an optimum pH value of 7.27. Aeromonas hydrophila can survive in water with a salt content of 0‰ to 4‰, with an optimum salinity of 0.5‰.

Aeromonas hydrophila can produce highly toxic exotoxins, such as hemolysins, tissue toxins, necrotizing toxins, enterotoxins and proteases. From the analysis of actual cases, it can be inferred that it mainly infects the intestines. Whether it can infect depends on the strength of the bacteria's adhesion to the fish's intestinal tissues. The strength of the adhesion is related to the strain and the type of fish. Usually, Aeromonas hydrophila strains with high adhesion can produce highly toxic exotoxins. The model of the cause of hemorrhagic disease can be described as follows: After Aeromonas hydrophila invades the fish body, it first proliferates in the intestines, then enters the liver, kidneys and other tissues through the portal artery circulation, causing liver, kidney and other organ and blood lesions, followed by systemic symptoms.

At present, there are many cases of fulminant hemorrhagic disease caused by Aeromonas hydrophila in production. Because there are many self-cleaning types of Aeromonas hydrophila, and the infected objects are different, the symptoms are also different. Such as silver carp fulminant hemorrhagic disease, turtle septicemia, eel hemorrhagic disease, eel red fin disease, etc. This bacterium is a conditional pathogen. When the environment changes suddenly and the water quality deteriorates, it often co-infects with other bacteria (such as mild Aeromonas, Vibrio, etc.) to aggravate the disease. Diseases infected by Aeromonas hydrophila are generally more severe, mostly malignant infectious diseases, and have a high mortality rate.

The tests for screening drugs for treating Aeromonas hydrophila are all done by first isolating Aeromonas hydrophila from the liver, kidney, spleen and other internal organs of the specimen as the test strain, screening out sensitive drugs through antibacterial tests of the test drugs, and then conducting a comprehensive evaluation of the efficacy and practicality of the selected drugs through clinical application tests. It has been confirmed that highly sensitive drugs include: gentamicin, kanamycin, norfloxacin, tobramycin, Junduqing, rhubarb and gallnut, etc.; medium sensitive drugs include: furazolidone, furanas, chloramphenicol, compound sulfamethoxazole, phellodendron, forsythia, phellodendron, dichlorvos, trichlorvos and chlorine dioxide, etc.

When choosing therapeutic drugs, you can refer to the above drug screening results. Because there are many variant strains of Aeromonas hydrophila, special attention should be paid to the efficacy. Generally, the condition has improved significantly after the application of the drug, and the number of dead fish has decreased significantly, indicating that the use of the drug is effective. Otherwise, the drug should be changed in time. If oral drugs are selected, attention should be paid to the intestinal absorption of the selected drugs. For example, gentamicin and kanamycin are poorly absorbed in the intestine. They can be used for injection but not easy to be used for oral treatment. Secondly, the dosage should be accurate, and the dosage should reach the minimum bactericidal concentration. The properties of various drugs are different, and the dosage is also different. For example, the common dosage of rhubarb is 12/1000 of the feed amount, and the dosage of furazolidinone is 2/1000 to 3/1000. The first dosage of sulfa drugs should be doubled. In addition, the method of drug application should be scientific. Chinese herbal medicines can be used in decoction or powder, but it must be conducive to absorption; the whole pool should be splashed on a sunny morning, and the splashing should be uniform. When the photophobic drugs are splashed in the whole pool, they should be done in the afternoon and evening.