What are the common diseases of hairy crabs? How to prevent and cure?

Hairy crab is a kind of economic crab, also known as river crab, hairy crab, clear water crab, which is a famous delicacy in China for a long time. In recent years, the culture model of high density, high input and high output has greatly promoted the enthusiasm and economic benefits of hairy crab farmers. Hairy crab disease is one of the key factors affecting high yield, in the specific breeding process, what are the common diseases of hairy crabs? How to prevent and cure?

Common diseases and symptoms of hairy crabs

1. Water mold

Main symptoms: 2cm~3cm gray cotton flocculent hyphae appeared on the body surface and appendages or wounds of the diseased crab and propagated deeply through the muscles and spread to the interstitial space. After stimulation, the hairy crab secreted a large amount of mucus, slow action, loss of appetite, weak physique, ulceration and spread of the wound tissue, and finally died because it could not molt.

2. Edema disease

Main symptoms: the abdomen, abdominal muscles and lower back shell of the diseased crab are swollen, transparent, slow, stranded on the shore, do not go into the water, do not eat, and finally die of failure. The disease is caused by bacterial infection after abdominal injury of hairy crabs.

3. Enteritis

Main symptoms: loss of appetite, slow movement and white body color of diseased crabs. After dissection, it was found that the intestines were red and without food and feces, and sometimes the liver, kidney and Gill also had pathological changes, sometimes showing gastric ulcer and spitting yellow water from the mouth. Sometimes liver, kidney, Gill also have pathological changes, sometimes show gastric ulcer and mouth spit yellow water.

4. Black mumps

Main symptoms: at the beginning of the disease, some of the Gill filaments are dark gray or black. With the development of the disease, all Gill filaments turn black, Gill filaments are incomplete, terminal and respiratory organs are necrotic, dyspnea, slow movement, often on the shore or attached to aquatic plants, serious death within a few days.

II. Treatment of common diseases of hairy crabs

1. Treatment of water mildew

Wash the diseased crab 3min~5min with 3%-4% saline solution, or wash the diseased crab 25min~30min with 3g/m3~5g/m3 's chlorpromazine (main ingredient: gallnut) solution.

The whole lake is sprinkled with dibromohydantoin (main ingredient: dibromohydantoin, specification 10%), and the water depth dosage is 150g/ mu / m~200g/ mu / m.

Sprinkle Shuimaojing (main ingredients: gallnut, forsythia, sulfamethazine, synergist) in the whole lake, the dosage is 50g/ mu / m, when there are more water molds, it can be increased to 50g/ mu / m~80g/ mu / m.

2. Treatment of edema disease.

Calcium oxide (quicklime) was sprinkled in the whole lake, the dosage was about 15kg/ mu / m, and the pH value was adjusted between 7.5 and 8.5.

The main ingredient: tetramethylol phosphate sulfate, high osmotic fungicide, adsorbent, decomposing agent, chelating agent, etc.), the dosage is 150g/ mu / m~200g/ mu / m, once a day, twice a day.

The granules were scattered in the whole lake (main components: bromochlorohydantoin, percalcium, oxidant, etc.; content specification: 100g:24g), the dosage was 150g/ mu / m~200g/ mu / m, once every other day, twice a day.

3. Treatment of enteritis.

The rats were fed with fungus toxin (main ingredients: Coptis chinensis, Scutellaria baicalensis, Cortex Phellodendri, Rhubarb, Gardenia jasminoides, Herba Euphorbiae, Flos Lonicerae, Houttuynia cordata, immune enhancer). Every 10 tons of feed was 40g~50g, and 3d~4d was fed continuously.

Povidone iodine solution (main ingredient: povidone iodine, compound of 1-vinyl-2-pyrrolidone homopolymer and iodine; specification: 10%) was sprinkled throughout the lake, the dosage was 300ml/ mu / m~500ml/ mu / m, once every other day, for 2 ~ 3 times.

The whole lake sprinkled biquaternary ammonium salt complex iodine (main composition: double octadecyl dimethyl complex iodine, stabilizer, complexing agent, etc.; raw material specification: quaternary 40% iodine 4%), dosage is 100g/ mu / m~150g/ mu / m, every 2 ~ 3 days, continuous use 2 ~ 3 times.

4. Treatment of black Gill disease.

The whole lake was sprinkled with calcium oxide (quicklime) at the dosage of 10kg/ mu / m~15kg/ mu / m to keep the aquaculture water weakly alkaline.

The whole lake is sprinkled with strong disinfectant Ling (main ingredient: sodium dichloroisocyanurate; specification: 20%), the dosage is 180g/ mu / m~200g/ mu / m, once a day, 3 times in a row.

The whole lake was sprinkled with bromochlorohydantoin powder (main ingredient: bromochlorohydantoin; specification: 24%), the dosage was 80g/ mu / m~110g/ mu / m. Once a day, twice a day.