Prevention and control techniques of eel disease

The eel refers to the general name of the species under the classification of the eel order. It is a kind of fish with a long snake-shaped appearance, which has the basic characteristics of fish, similar to salmon with migratory characteristics, scaleless, generally produced in the sea area at the junction of saltwater and fresh water, and is rich in nutritional value. it has a high breeding prospect, so let's take a look at the disease prevention and control technology of eel.

Gill nephropathy

[symptoms] Gill nephropathy showed no obvious symptoms, Gill swelling, Gill dark red, Gill flap hypertrophy, adhesion, Gill leaf bleeding, laboratory plasma examination, chloride ion was significantly lower than that of healthy eel, when the disease was prevalent, it could cause devastating death.

[prevention and treatment methods] the use of antibiotics in Gill nephropathy is basically ineffective. Salt is injected at the initial stage of the disease to make the pool water reach a concentration of 0.4% and 0.7%. Offshore infusion of seawater is also effective, and other drugs are used to treat other diseases.

Liver and kidney disease

[symptoms] Hepatonephropathy, also known as Edward's disease, is caused by Edwardsiella bacteria. The onset temperature is 15 ℃ and the peak temperature is 25-30 ℃. It is a common and serious disease. The pathogen invades liver and kidney, and is divided into liver type and kidney type. Kidney type is common in white and black stage, liver type is more in adult eel stage, liver enlargement or ulceration can be seen in anatomy, perforation of skin and muscle ulcer can be seen. The kidneys are obviously swollen and solid.

[control methods] in the stage of domestication, ① white cubs should be thoroughly disinfected and silk earthworms should be cleaned. ② is regularly bathed with 30 mg / L formalin and 3-5 mg / L furazolidone. In the white stage of ③, the temperature can be reduced to less than 25 ℃ and put into formula feed as far as possible. ④ antibiotics are mixed with bait, 30-50 grams per ton of eel for 5-7 days. ⑤ allicin and norfloxacin were fed with 3-5 grams of bait per kilogram for 5-7 days.

Red fin disease

[symptoms] Red fin disease is caused by Aeromonas hydrophila and Aeromonas maculata. The skin and fins of diseased eels are congested, bleeding, obviously red, ulceration occurs in severe cases, hepatomegaly and splenomegaly, and high mortality occurs all the year round. It occurs more seriously in spring and summer, mostly in eel species and adults.

[prevention and control methods] when ① cleans the pond, thoroughly remove the sludge from the bottom of the pond, throw 30% 40% limewater on the bottom and wall of the pond, or soak the pond with 2 mg / L bleach for 5-7 hours. ② eel species are soaked in 3% murine 5% salt water for 10-15 minutes or 5-6 mg / L furacilin for more than 30 minutes before being put into the pool. The pond with ③ was disinfected with 25-30 mg / L formalin or 1-2 mg / L furan. ④ gives eels oral antibiotics. 100 mg of sulfonamides per kg of heavy fish (doubled for the first time), 20 mg of tetracycline, oxytetracycline, chloramphenicol and 4 mg of furan, mixed and fed in feed once a day for 5-7 days.

Gill rot disease

[symptoms] Gill rot disease is caused by bacteria or some parasites invading the Gill, the appearance of the diseased eel is almost not abnormal, the diseased fish swim alone, float the head, open the Gill petal, the Gill filament tissue is destroyed, and the defect is large. With the development of the disease, light pressure with the fingers on the Gill of the diseased eel, there is blood mucus outflow, anemia, white, liver yellowing white, mostly occurs in the high temperature period, the main harm to adult eel, eel species rarely occur, sporadic death. Overfeeding and overeating are the causes of the disease.

[prevention and treatment methods] ① prevents overeating, stop feeding or less compound feed when the disease occurs, and switch to raw bait where there is raw bait. ② is treated with antibiotics, sulfonamides, furans and other drugs, mixed with feed, the dosage is the same as red fin disease. ③ sprinkles with furan and formalin, sprinkles the pond with 0.8-1mg / L potassium permanganate, or bathes with 0.5% salt water. When nematodes or other parasites are found by Gill examination, 0.2-0.4 mg / L trichlorfon is sprinkled and used again every 2-3 days for 2-3 consecutive times.