Culture technology of Monopterus albus

Key points of Monopterus albus culture technology

Eel meat is delicious and nutritious, and is known as "Sai Ren". At the same time, its medicinal value is also very high, and it is paid more and more attention to in cultured varieties, and its price remains high. The key points of aquaculture technology are introduced as follows:

I. Construction of Eel Pond

1. The area of the cement pool should be 30 ~ 50 square meters, and the surface and bottom of the pool should be polished and smooth to prevent eels from scratching their skin during activities and causing various infections of bacteria and viruses. The top of the pond should be about 30 cm above the water surface, and a natural overflow port should be set up, and the outlet should be fixed with a net to prevent the eel from escaping. There are two ways to raise eels in cement ponds: soil culture and soilless culture. In both ways, water peanuts or water hyacinths should be planted to adjust the water temperature and provide rest for eels in hot season, leaving only a few feeding holes when the whole pond is full. If there is soil, it should be paved with 20 cm ~ 30 cm soil, and the water level above the mud layer should be kept at 20 cm ~ 25 cm. If the water is too deep, eels will consume too much energy in their activities. If the water is too shallow, the water will be turbid and the water temperature will change greatly. If the water level of soilless culture is maintained at 30 cm ~ 40 cm, the advantage of this culture mode lies in the good disinfection effect of water body, while in soil culture, the drug force is difficult to act on the soil and bottom during disinfection, and it is easy to breed various parasites and their intermediate hosts, such as leeches, flat-leaf snails and vertebral snails.

2. Paddy field cultivation: first dig out paddy field soil, bury it in a net box, and then put it back in the net box. The four corners of the net box are fixed, and water peanuts or water hyacinths are planted, with an area of 20 square meters to 30 square meters. It is not suitable for planting crops with rough roots, such as rice, in cages, because eels have the habit of digging, which is easy to scratch the epidermis.

3. All kinds of ponds, lakes and reservoirs are cultivated by net, that is, cage soilless culture, with an area of 15 square meters to 20 square meters, which is convenient for disinfection. When the disease occurs, the cage and fish can be directly put into a large disinfection container. Aquatic plants such as water peanuts or water hyacinths should also be kept in cages for eels to rest.

The area of the above breeding mode should not be too large. If it is too large, it will easily lead to an increase in the size difference of eels during the breeding process, which is not conducive to growth.

Second, seed selection

Monopterus albus varieties with large and dense black spots should be selected, which grow fastest; Yellow with small spots and irregular appearance; Yellow and black grow slowly; Black or blue-black plants grow slowest, but they are relatively fierce.

When selecting seedlings, we should pay attention not to choose injured seedlings, electric shock seedlings, fishing seedlings and interplanting seedlings, but to choose healthy seedlings with strong vitality, strong ability to swim against the current and quick response to touching the tail. When selecting seeds, you should choose seedlings with the same size and specifications, because eels kill each other, especially when the bait is insufficient.

Thirdly, the effects of water temperature and ph value on eels.

Monopterus albus is very sensitive to the change of water temperature. The suitable water temperature for growth is 15℃ ~ 30℃, and at 28℃, the activity is the strongest, the growth speed is fast and the feed utilization rate is high. During this time, we should pay attention to the feeding of feed to make the eels full. When the water temperature is lower than 15℃, Monopterus albus does not eat and hibernates. Therefore, in Jiangbei area, when the water temperature is unstable in April, do not add water or bait to lure the eel out of the hole, so as to avoid the eel disease caused by the large change of water temperature. Eels can overwinter by wet method. The method is as follows: firstly, drain water to keep the soil layer moist, and when it is cold and snowy, add a layer of straw or hay to keep warm to prevent freezing; Deep-water wintering is also possible, but there is one disadvantage. In the second year, when the weather gets warmer, the eel will go out to look for food, but this method is easy to catch a cold and other diseases, because the weather and water temperature are unstable at this time.

PH value is also called PH value. In the process of feeding, if the dissolved oxygen is insufficient, the oxidation process will be inhibited, and the bait residue, organic matter, excrement and so on. If it is gradually accumulated and decomposed insufficiently, organic acids will accumulate, which will reduce the pH value and affect the growth of eels. Therefore, attention should be paid to replacing fresh and clean water during the breeding process. Because eels like clean water, we should pay attention to changing water frequently and measuring pH value. Eels are generally suitable for living in neutral or weakly acidic waters (pH value is 6.5 ~) and should be treated as such in the onset season. Because the water is changed too quickly, it is easy to cause a large temperature difference and make the eel catch a cold.

Fourthly, fish pond management.

1. The disinfection time of fish ponds should be set at about 10 days before stocking fry, because there may be residual poison in fish ponds too late and bacteria will easily breed again too early. During disinfection, the pool water should be kept at a height of 5 cm ~ 6 cm and disinfected with 90 g/m2 ~ 120/m2 quicklime. On the second day after disinfection, it is best to mix the mud and lime milk with a rake to make it fully play its role. During disinfection, fresh water is put in every 1 ~ 2 days, and old water is discharged.

2. Before disinfection and stocking of fish fry, in order to determine whether there is residual poison in the fish pond, 5 cm ~ 10 cm of bighead carp or silver carp fry can be used as "test fish" according to 2 ~ 3 fish per square meter. If the fish activities are normal and the toxicity has disappeared, otherwise the stocking should be postponed. Before stocking, fry are soaked in 3% ~ 5% salt for 10 min ~ 15 min, or disinfected with 2 ppm ~ 5 ppm potassium permanganate, which can eliminate some pathogens and parasites and increase disease resistance. Disinfection is best carried out in a cool place to avoid sun exposure. Time can be appropriately increased or decreased according to the physique of eel fry to see if there is any abnormality. After disinfection, it should be temporarily raised and stocked in clear water. When stocking, divide the pools according to the specifications to avoid killing each other. It should also be noted that the water temperature of the temporary pond should be equivalent to that of the big fish pond (i.e. the stocking pond), and the temperature difference between them should not exceed 3℃. If the difference is large, adjust the water temperature appropriately.

3. Feeding management and growth Some fresh water will be added about one week after Monopterus albus enters the pond, and then 1 time every 2 ~ 3 days, preferably 3 cm ~ 5 cm each time, so as to keep the water level at about 25 cm. When summer is hot, the number of water changes can be increased appropriately, preferably 3 cm ~ 5 cm each time, so as to avoid excessive temperature difference.

Patrol the pond every day, and find the sick eels out in time to analyze the reasons (sick fish generally don't enter the hole, but swim on the water). Adhere to intensive cultivation, timing, timing, qualitative and quantitative feeding. At ordinary times, 1PPM bleaching powder or 0.2PPM trichlorfon can be used to prevent diseases in the whole pool (90% crystal form), and several kinds of preventive drugs should be prepared and replaced frequently to prevent pathogenic bacteria from developing drug resistance.

The growth rate of eel has a great relationship with the nutritional composition, species and quality of bait. In traditional culture, it is difficult to ensure the freshness of small fish, shrimp, earthworm, mussel and snail, and eels are prone to rancidity and illness. The nutritional components are relatively simple, mainly in protein, and the content of protein in imported wild fish is not high. Eel's digestive organs are weak, and it is not easy to rancidity and deterioration. The nutrients are relatively simple, mainly in protein, and the protein content of these wild fish is not high. The digestive organ of eel is weak, which is not easy to digest and absorb, so it is not suitable for the growth requirements of eel. Especially chilled fish and mussels are not easy to digest and absorb, which is easy to cause enteritis. Feeding earthworms is easy to get various parasitic diseases. Earthworms live in moist and fertile soil, and all kinds of parasites like to breed and lay eggs in this environment, so earthworms become indirectly infected eels. In order to improve economic benefits, large-scale eel fry should be selected to achieve the purpose of listing that year, so eels should be fed with complete compound feed with comprehensive nutrition and easy digestion and absorption. At present, there are three kinds of compound feed for Monopterus albus in the market, namely powder feed, pellet feed and puffed feed. Both powdered and granular feeds inevitably have some shortcomings, such as easy dispersion, water pollution, and difficulty in observing feeding conditions. Expanded feed has good floatability, high stability in water, light water pollution, easy observation of feeding situation, high temperature sterilization during expansion, and no germs, so it is the first choice in breeding feed. Farmers should choose good feed manufacturers and well-known brands to ensure product quality. At present, the "Yinxiang" and "Fuxing" eel puffed feed on the market has been recognized by farmers.

Five, the main diseases and their treatment

1. Hemorrhagic diseases

The cause is unknown and belongs to septicemia. Eels fed with earthworms are more susceptible to this disease, and hemorrhagic diseases and enteritis are prone to secondary parasitic diseases.

(1) Symptoms: There is blood sample liquid in the mouth, which will flow out in turn, especially after death. The body surface is covered with bleeding spots of different sizes, especially the abdomen. The anus is red and swollen, everted and bleeding, and sick fish often take a deep breath out of the water. Local farmers in Hubei called it a "vertical pile", which kept turning around and cutting open the stomach, showing liver bleeding, swollen spleen and purple rectum bleeding.

(2) Treatment A. Spraying furazolidone 0.2 ppm ~ 0.35 ppm (using furazolidone powder) in the whole pool. B. take 5 grams of norfloxacin orally/100 kilograms of fish, and mix the ingredients. C) Soak the tobacco leaves in 250g warm water for 5-8 hours, with a water depth of 30cm/ mu, and sprinkle them in the whole pond. D. Erythromycin 250,000 units soaked sick eel. The above a and b can be used at the same time, and a and c can be used alternately every other day for 3 ~ 5 days.

2. erythroderma

(1) Symptoms: The sick fish moves slowly and feebly, sticking its head out of the water all day, local bleeding and inflammation, erythema, severe skin rot and intestinal congestion and inflammation, which is different from hemorrhagic disease.

(2)a. 1 ppm bleaching powder solution is sprayed in the whole pool for 3 days. B. soak the sick eel with erythromycin.

3. Enteritis

It is mainly caused by feeding spoiled frozen fish and mussels or insufficient feeding and excessive hunger.

(1) Symptoms: slow movement, no eating, dark body color, emaciation, intestinal congestion, yellow mucus flowing out, red and swollen anus, and purple in severe cases.

(2) Treatment: Take 5 kg of allicin or Polygonum hydropiper per 100 kg of fish for prevention. Add 3 kg to 4 kg of mint to every 100 kg of eel and pour it with boiling water 1 time /7 days ~ 10 day.

Every 100 kg of fish during treatment:

A. People use 10 drops of water and 20 ml of water to mix materials.

B. sulfonamides 10g× 3 days mixing.

C. 5 grams of norfloxacin x mixing for 3-5 days.

4. Capillary nematodes and echinococcosis feed on earthworms, which are white slender worms and are easy to cause enteritis.

(1) processing:

A. Spray 0.5 ppm ~ 0.7 ppm of 90% crystal trichlorfon solution on the whole pond, and prepare enough water when spraying. Because eel is very sensitive to trichlorfon, improper dosage will lead to the death of the whole pool, and trichlorfon is prohibited to be taken orally.

B. Take orally 5 g to 7.5 g levamisole or equivalent albendazole per 50 kg eel for 6 days.

C. Spray 0.7 ppm mixture of copper sulfate and ferrous sulfate (5: 2) on the whole pool to kill parasites.

5. Trypanosomiasis is easy to cause anemia and big head. The medicine can be soaked in the same amount as in (4).

6. Tail rot is mainly caused by insufficient bait, cannibalism or self-harm. Pick up the fish and dip it in erythromycin or splash 1ppm bleaching powder.

7. Coma is mainly caused by hot weather, high temperature and shallow water. You can chop up fresh mussels with water and scatter them in the pool, or chop up fresh gourds and melons.

8. The temperature of cold water is too high or too low, or a large number of water is changed suddenly, resulting in fish body dysfunction and death. Keep the water level and change the water reasonably.

9. The main density of fever is high, the weather is hot, the fish secretion in the water is too much, oxygen is consumed, the water quality is not clean, and the bait residue or small fish and mussel meat are not fished out and stink. The prevention method is to change water; B. Sprinkle 0.7ppm ketone sulfate or 25 kilograms of water and 300,000 units of penicillin.