How to prevent and treat shelling failure in river crabs?

The posterior edge of the cephalothorax and the abdomen of the river crab have appeared a crack, but can not shed the old shell, resulting in the phenomenon of death, mainly harming the middle and late adult crabs, especially the adult crabs with more hypertrophied individuals, this disease often occurs.

1）**。The disease is caused by a disease or a lack of calcium and certain trace elements in river crabs. The sick crab has a black back, obvious brown patches on the dorsal carapace, and a crack appears at the junction between the posterior edge of the dorsal carapace and the abdomen, and dies due to inability to molt.

2) Prevention and control methods.

Check whether the river crab suffers from other diseases, apply the symptomatic medicine, and carry out **.

20 grams of quicklime per cubic meter of water, splash the whole pool of water, 1 time in 5 days, 3 4 times in a row.

Add an appropriate amount of shell powder and ecidin to the feed, and increase the amount of animal feed.

The ** calcium deficiency, unbalanced nutrition, or gill and liver infection by bacteria or viruses. Sick crabs do not moult smoothly within the normal time. Even if the shell is shed, it usually dies after 1 day.

Precautionary measures Regularly use beneficial microbial preparations such as photosynthetic bacteria to maintain good and stable water quality; Regularly use povidone-iodine solution, chlorine dioxide and other whole pool disinfection; Use quicklime once every half a month, and splash the whole pool according to 30 40 grams per cubic meter of water; Before the crab body molts normally, add drugs to the bait to promote the growth and molting of the crab shell.

**Measures add river crab compound additives and calcium dihydrogen phosphate to the feed, feed continuously for 3 5 days, and use a course of treatment after 7 10 days.

Crabs are detoxifying the shell can be used to detoxify, which can improve the crab's anti-stress ability and increase the crab's body nutrition. It is recommended to sprinkle nutrients containing calcium and magnesium components such as calcium magnesium crystal, calcium magnesium multi-mineral treasure, etc., to help crab carapace hardening, prevent unsuccessful shelling, supplement crabs' demand for calcium and magnesium and other minerals, and add an appropriate amount of multivitamins and ecidin or shell powder, bone meal, eggshell powder, fish meal, etc. to the feed of the banquet, so as to facilitate the synchronization of crab shelling and shelling, so as to lay a solid foundation for the smooth shelling of crabs.

Summary. Directly reduce the hardening rate of shelled crabs. If there is too much cyanobacteria during the crab shelling period, it needs to be detoxified, and mechanical oxygenation and manual removal are the main ones.

Hello dear, directly reduce the hardening rate of shelled crabs. If there is too much cyanobacteria during the crab shelling period, it needs to be detoxified, and mechanical oxygenation and manual removal are the main ones.

New water has been added to the pond Do you need to detoxify now?

If the detoxification is not thorough, it is easy to sell and close, resulting in the death of river crab seedlings. If you use pyrethrin to carry the crack and trichlorfon Qingyin sock pond, it is recommended to wash the pond with water first, put the water away, and then use the detoxification spirit to detoxify once, and then use the detoxification Bishui An to detoxify one to two days before the seedlings.

Now there are seedlings in the pond Now it is also the shelling period I have added new water in the past two days Do you need to detoxify.

This is not advisable and generally pond turning and disinfection are carried out 10 to 15 days before.

Can you take calcium during the shelling period now.

OK. Ask about custom messages].

The degradation of crab germplasm, the deterioration of pond water quality, the spread of diseases, and the incomplete nutrition of feed are the main reasons for the failure of river crab molting. The lack of certain nutrients in the breeding process, such as the long-term lack of calcium, phosphorus, iron and other elements in the aquaculture water, and the long-term lack of essential amino acids, bile acids, ecidin, etc., will lead to the occurrence of molting.

The selection of healthy and vigorous high-quality crab seedlings and the strengthening of water quality management are still the most basic tasks to prevent and control the failure of river crab molting. However, the internal health care prevention and treatment methods in nutrition have also attracted more and more attention. Many farmers do not pay attention to internal health care, in addition to being troublesome, mainly doubting the existence of the effect.

In fact, the effect of taking fortified health supplements containing bile acids is obvious.

Bile acids, like cholesterol, are essential nutrients for the growth of shrimp and crabs, and are the precursors of the body's synthesis of ecdysone. The addition of bile acids to the feed can increase the synthesis of ecdysone in the body, ensure that the content of ecdysone is sufficient, and regulate the normal and smooth molting of river crabs. Bile acids are the most important nutritional factors to ensure the smooth and complete molting of river crabs, and they can prevent and control the molting failure of river crabs by regulating the synthesis of ecdysone, promoting nutrient metabolism, reducing the burden of hepatopancreas, and enhancing the function of hepatopancreas, so as to increase the income of farmers.

Tremor disease is also known as tremor disease and ring claw disease. At the beginning of the disease, the limbs of river crabs can still be straightened, and then they will retract and cannot be straightened. The sick crab is unsteady on its feet, has difficulty turning over, has weakness in movement, cannot crawl, trembles continuously, has no appetite and stops feeding, has water in its body, and dies after 4 to 5 days.

1) Pathogens. The causative agent of the disease may be viruses, vibrio and rickettsia, etc., and it is presumed that the bacterial primary infection is the first infection, and the virus is the secondary infection.

2）**。Due to the incomplete cleaning of the pond, the aging of the pond, the poor water quality, and the crab species with pathogens into the pond, etc., the feeding of the sick crab is significantly reduced until it refuses to eat, it is difficult to molt, it is slow to crawl, there is no ability to resist and escape, and it often crawls in the shallow water or aquatic plants at the edge of the pond, and the appendages are constantly shaking, so it is called "shaking disease".

3) Precautionary measures.

Ponds should be thoroughly disinfected and excessive silt should be removed.

Crab ponds should be planted with more aquatic weeds, and the aquatic weeds should cover 50% to 60%.

Strengthen water quality management and keep water quality clean.

Pay attention to the nutritional balance of the feed, and appropriate plant-based feed.

Regularly sprinkle disinfect with 15 milliliters of bleaching powder or milliliters of bleaching precision (strong chlorine).

4) Method.

Sprinkle with 15 milliliters of bleaching powder or milliliters of milliliters of bleaching powder on the whole pool for 2 days, and after 7 days, sprinkle with 15 milliliters of quicklime once in 1 time.

Add oxytetracycline or doxycycline to the feed for 5 days.

Each kilogram of crab was fed with 10 grams of radix radix, oxytetracycline grams, morpholinoguanidine grams, mixed with feed, and used for 15 days.

Sick crabs have significantly reduced their feeding until they refuse to eat, have difficulty molting, crawl slowly, have no ability to resist and escape, often crawl in the shallow water by the pond or on aquatic plants, and their feet and limbs keep shaking, so it is also called "shaking disease".

The pond was thoroughly cleaned with quicklime, and the purchased crab species were strictly quarantined, and the medicated bath was disinfected. Adhere to the principle of "four determinations" feeding, do not invest in spoiled feed; In the high temperature period of July and September, keep the pond water depth more than 1 meter, splash the whole pool with quicklime 15 20 grams of m3 every half month, and splash the whole pool once every month with 1 g of calcium diphosphate or 1 g of calcium dihydrogen phosphate, and keep the water fresh. Sick crabs and dead crabs should be harmlessly treated, and dead crabs should be dug and buried in a concentrated manner, and the diseased pond should not be changed with water, but only filled with water, so as to avoid expansion or cross-infection.

Splash the whole pool with a crab shake of gram 3, and splash it with a crab water treasure of 10 gram of 3 meters after 3 hours, and use both once a day for 2 days. 400 grams of crab shake stop No. 2 were added for every 50 kg of feed for 5 days; Or add every 50 kg of feed to the Radix Root, Virus Ling Kilogram, Multivitamin Kilogram feeding, continuous feeding for 3 5 days.

River crab rot claw (limb) disease is one of the common diseases in aquaculture.

1) Symptoms. From the claws of the crab's foot, it begins to rot until it reaches the base of the foot, and there is no flesh in the limbs, and finally the limb is severed until it dies. The disease is severe in the early stages of stocking, and it is also common in fishing later. Microscopic examination showed that

There are a large number of vibrio bacteria and fungi in the decay site, and it has been verified that the ** of the rotten claws is caused by the invasion of vibrio bacteria that can decompose chitin from the wound of the river crab, and the fungus is infected afterwards.

2) Prevention and control methods.

When detaining crabs in transportation, the mouth of the net bag should be tightened first, and then the crops such as aquatic weeds or foam should be padded on the transport vehicle, and finally the crab tools such as the net bag should be slightly fixed, and the operation should be light during the fishing process, and the injured crab should be properly disposed of in a timely manner.

Before stocking, it should be soaked in bacterial poison for 5 10 minutes, and then stocked.

In the process of feeding, the whole pond should be splashed with dibromohydantoin or bromochlorohydantoin to prevent disease before and after the high temperature season.

According to the feed feeding status, decide whether to add ecidin and crab multi-dimensional to the feed to promote the healthy growth of river crabs.

Failure to shell: also known as the top shell pull foot with cap, is one of the factors that affect the annual survival rate of crabs, due to many influencing factors, so when there is an unsuccessful shelling, we must find out the reason, do not drug at will, because at this time the crab is in a large number of shelling, the diagnosis is inaccurate and the drug is used, which often brings incalculable losses. The occurrence of unsuccessful shelling of river crabs is more serious, and some sick crabs have the phenomenon of "lifting their shells", and there are cracks at the junction between the carapace and the abdomen, but they cannot be shed, or they die soon after the shells are taken off; Some do not stare at the phenomenon of "lifting the shell", and the new shell skin can be seen when the carapace is uncovered, but it is attached to the shell, mostly because it cannot take off the hole and stupid shell.

In the early stage of a shell, we must pay attention to detoxification (detoxification), the fertilizer of the pool water is lively, only the water quality is good, in order to have sufficient dissolved oxygen, in order to be smooth shelling. Oral nutrition**60 kg per bag. The crab itself has a constitution.

3.It was found that three days after shelling, a group of 3 acres of stress crustacealytic ** polysaccharides was used, and then trembling and used again after a week.