Leech breeding technology

1. Medicinal uses and breeding prospects of leeches

Leech, scientific name is leech, is a valuable medicinal material that has been cultivated in many countries in the world since ancient times. The habit of using leeches as medicine. The main functions of leeches are: first, to expel evil blood stasis and blood stasis, and second, to break up blood accumulation. It is used to treat women's blood stasis, amenorrhea, hemometriosis and other diseases. Today, Chinese patent medicines made from leeches, such as Dahuangchong Pills, Han's Pansukang, Bailao Pills, Shengxi Xuanshuangxinmaining, etc., have been put into mass production and are in short supply. Domestic demand for dried leech products alone reaches thousands of tons every year. Japan and South Korea have long relied on importing leeches from my country.

With the widespread use of chemical fertilizers and pesticides, as well as the predatory capture of leeches in recent years, wild leech resources are decreasing day by day, and they are far from being able to meet the needs of medicine. Due to the extreme shortage of supplies, artificial breeding is now carried out in many places. Leeches have strong vitality and reproduce very quickly (leeches are hermaphroditic, each leech lays eggs and reproduces 60 to 90 little leeches each time), and is easy to raise and manage. The scale of artificial breeding of leeches can be large or small, with low investment and high efficiency. One acre of water surface breeding pond can harvest 400 kilograms of finished products worth more than 20,000 yuan. It is indeed a promising and stable way to get rich for rural households.

2. Characteristics of medicinal leech breeding

1. Strong Adaptability Medicinal leeches are extremely adaptable to changes in biological environments and can be cultured throughout the country. Medicinal leeches can adapt to all mountains and plains. You can also use the front and back of the house, the courtyard, the balcony, and the pond for breeding.

2． Amazing hunger tolerance. Although medicinal leeches are gluttonous and eat a lot of food, they have extremely strong hunger tolerance and are not afraid even if they are starved for a long time.

3. Breeding techniques are easy to master. Medicinal leeches like to eat invertebrate aquatic insects. If aquatic insects are mixed with medicinal leeches in proportion, there is no need to feed them specially. As long as the water quality is managed well, they can grow well.

4． Medicinal leeches are large, generally dozens of times larger than ordinary leeches.

5． It requires less labor and can be cultivated by men, women, old and young in their spare time.

6． Leeches are hermaphroditic and heterosexually mate. As long as good sources are introduced, they can reproduce on their own year after year.

3. Artificial breeding technology of leeches

1. When choosing a site to build a pond, choose a location that is sheltered from the wind, faces the sun, and has convenient drainage and irrigation. The pool is 3 meters wide and 1 meter deep, with no limit on length. There are water inlets and drainage outlets at the opposite corners of the pool, and some rocks and branches are placed on the bottom of the pool for leeches to inhabit. Small-scale farming can use puddles, waste ponds, and ponds for farming. All drainage inlets must be barricaded with barbed wire or plastic mesh to prevent leeches from escaping.

2． For artificial breeding, money leeches (commonly known as cow leeches) are the best for artificial breeding. Brown leeches can also be put in here. Money leeches are extremely common in rice fields, ponds, streams, and jungles. Care should be taken to identify them when catching them for seed production. The seed stocking standard is about 10,000 per cubic meter. The selection criteria are: strong, harmless, large in size (20-30 grams is best), such leeches lay a lot of eggs, have a high hatching rate, and can be processed and sold after being raised for 10 months.

3. Feeding: Leeches mainly feed on the blood of snails, clams, frogs, turtles, earthworms and mammals. Artificial breeding can use a variety of blood-mixed feeds, grass meal, and even feces. About 25 kilograms of live snails can be released per acre at a time to allow them to reproduce naturally and allow leeches to feed freely. Animal blood is generally fed once a week. The specific method is: put the blood clots of pigs, cattle, sheep and other animals into the pool, and place one piece every 5 meters. The leeches will quickly gather after smelling the fishy smell, and then disperse on their own after sucking.

4． Management technology: First, regulate water quality. Although leeches can grow in sewage, due to the high density of artificial breeding, the water quality should be kept fresh and a certain amount of dissolved oxygen must be ensured. When the oxygen content in the water is less than 2 mg/L, leeches will surface and appear. uneasy phenomenon. The water temperature is high in summer, so be sure to change the water appropriately. The second is winter management. Leeches hibernate in winter, and those released in early spring are generally well grown and can be processed and sold. When fishing, drain the water first and then pick it up with a net. Select seeds that are large and strong in growth. 10 to 15 kilograms should be left per acre and put into breeding ponds for overwintering. When the temperature of the thermal insulation pool is above 15°C in winter, leeches can feed and grow, thereby shortening the breeding cycle and achieving the purpose of year-round breeding. When the water temperature of the breeding pool is between 15 and 30°C, leeches grow well. They stop feeding below 10°C and above 35°C, their growth is affected.

5． Reproduction Leeches reproduce quickly and have strong regeneration power.

The spawning period in the Yangtze River Basin is generally from late April to mid-June. For artificially bred leeches, the egg cocoons are laid in the soil near the water on the platform of the breeding tank, and they are oval in shape. Each leech produces about 4 cocoons at a time. Little leeches hatch out about 16 to 25 days after the cocoon is produced. There can be 13 to 35 leeches in each cocoon. The little leeches are dark yellow in color and grow rapidly, with an average length of 20 mm within one month after hatching.

6． Transportation Leech is usually transported by carry-on method. The specific method is as follows: put some aquatic plants in a mesh bag, put the leeches in, tie the mouth of the bag tightly, then put it into a basket or basket, and then transport it away.

7. Processing method

(1) Blanch the washed leeches with a handle and put them into a basin or other container. Pour in the boiling water suddenly. It is advisable to submerge 2 to 3 fingers of the leeches in the hot water for about 20 minutes. After the leech dies, take it out and put it in a clean place to dry.

(2) Lime method: Put the washed leeches out and bury them in lime for 20 minutes, then take them out to dry in the sun or oven, and sift out the lime powder.

(3) Wine suffocation method: Pour high-quality white wine into the leeches until they are submerged.

(4) Raw drying method: Thread the caught leeches with wires and hang them directly in the sun.

The above methods are for reference only. Other issues that need attention:

(1) The water scalding method is prone to moisture when drying. You can use iron nails or bamboo tips to deflate while drying.

(2) Choose a sunny day. If it cannot be exposed to the sun on cloudy days, it will easily become rotten. If it suddenly rains and cannot be exposed to the sun, it should be placed on an iron vessel and dried over fire. But don't bake it until it's burnt or browned.

(3) Put the dried leeches into plastic bags and seal them to prevent moisture absorption and mildew. The dryness standard is preferably one that can be broken by hand. The ratio of fresh to dry products is: about 7 kg of large leeches can be used to dry 1 kg of dried products, and about 8 to 10 kg of small leeches can be used to dry 1 kg of dried products.

Standards for high-quality dried leeches: naturally flat and spindle-shaped, with a slightly raised back and flat ventral surface, brittle and easy to break, a gelatinous cross-section, and shiny ones are preferred. When storing, keep it in a dry place to prevent insects.

Leech breeding technology: Leeches, commonly known as leeches and horse turtles, belong to the phylum Annelida, class Bleeculata, order Hirudales, and family Hirudidae. They grow and reproduce in inland freshwater waters and are a traditional special medicine in my country. The dried products of aquatic animals are processed and used in traditional Chinese medicine. They have the effects of treating stroke, high blood pressure, clearing blood stasis, amenorrhea, bruises, etc. In recent years, it has been newly discovered that leech preparations have special effects in preventing and treating cardiovascular and cerebrovascular diseases and anti-cancer. Historically, it has been dominated by natural fishing. Due to the abuse of pesticides, chemical fertilizers, etc. and the pollution of the environment by industrial and agricultural "three wastes" in recent years, wild natural resources have declined sharply. With the in-depth development of the medicinal value of leeches, their market demand potential is huge. . Around 1995, southern my country began to capture natural seedlings and conduct artificial breeding for the first time, which was successful. Breeding has not been carried out in the northern region due to seed and technical reasons. When we summarized and guided several breeding cases in recent years, we proposed a set of artificial breeding techniques for leeches suitable for northern areas, which are introduced below.

1. Ecological habits of leeches

1. Living habits: Leeches are cold-blooded molluscs that can grow and reproduce in both north and south of my country. They mainly live in reservoirs, ditches, and rivers in fresh water. In paddy fields and lakes, ponds rich in organic matter or pollution-free rivers are the most common. The suitable growth temperature is 10-40℃. In northern areas, when the temperature is lower than 3℃, it enters dormant hibernation period in the soil. In March-April of the following year, it becomes active when the temperature is higher than 8℃. Leeches are omnivorous animals, and their main lifestyle is to suck the blood or body fluids of animals. They often feed on plankton, insects, and molluscs in the water. Under artificial conditions, they feed on various animal offal, cooked egg yolks, compound feeds, and plant residues. Freshwater snails, miscellaneous fish, earthworms, etc. are used as bait.

2. Reproductive habits Leeches are hermaphrodites, allogamous, internal fertilization, and have both male and female reproductive organs. During mating, they proceed in opposite directions. There is a "sex reversal" phenomenon in the life history, and there is an exchange of gender roles. A leech can be both a father and a mother, playing different roles at different times in its life. About one month after mating, the female's genitals secrete thin mucus, which is coated with an egg belt, shaped like a "cocoon". It is excreted from the body and hatches in wet mud at a suitable temperature. It takes about 16-25 days to hatch from the cocoon. The young leech begins an independent life.

2. Construction of Breeding Ponds

Leech has strong adaptability. It has a wide temperature range, is resistant to hunger and drought, and can live in various waters.

General lakes, fishing ponds, waterlogged depressions, rice fields, river ditches, and idle land in front of and behind houses can all be used to build ponds for breeding according to local conditions. For large-scale breeding, the pond should be built in a place that is sheltered from the wind and sunny, has convenient drainage and irrigation, and avoids escape. You can also choose to renovate and utilize various fishing ponds or waterlogged depressions. For the convenience of management, the pond area is not easy to be too large. The water depth is generally about 1 meter. There is a water inlet and a drainage outlet at the opposite corners of the pond. Some stones, tiles or branches are placed at the bottom of the pond for its habitat. In production, we used abandoned river ditches, dug partitions, and built serial ponds of different sizes. Each 2-3 ponds were a group. The first two ponds were cut off with pond ridges to leave inlet and drainage channels. It can activate water bodies to facilitate exchange, and is easy to manage and harvest, and has achieved good results.

3. Source of seedlings

1. Capture natural leech species and reproduce them yourself. From July to October when leeches are active and frequently appear, leeches are captured from natural waters as seed leeches and placed in a certain water body to preserve the seeds for overwintering. The leeches can reproduce on their own the following year. Adult leeches with a body length of more than 6cm have suitable conditions and can reproduce about three times a year. Self-propagation and self-reproduction are a convenient and labor-saving way and development direction. During breeding, a considerable amount of snails can be put in at one time, usually 25-30kg per mu, and the water quality must be controlled well. Feeding is done every 5-7 days during the hatching period. At the beginning, the bait is crushed and sprinkled with cooked egg yolks. In the middle and later stages, animal blood is mixed with bran, peanut shell powder or chicken and pig feed. The technology is simple and easy to implement.

2. Purchase seeds. Go to an artificial breeding farm to select young leeches that are neatly sized, active, powerful, and well-flexed as seeds.

3. Release seedlings. According to different breeding conditions, different seedling densities can be selected. The maximum number of seedlings per square meter for intensive cultivation in small cement tanks with good conditions is 1,000-1,500 seedlings/square meter. According to experience, for pond farming of about 0.3-2 acres, each pond can be invested with 100-300 leeches at one time to reproduce on its own. Young leeches generally reach gonad maturity in 120-150 days. In northern areas, the second generation can be reproduced in the same year when seedlings are released. The parent leech breeds 2-3 times a year, and each individual lays about 300 eggs.

4. Feeding and management

1. Feeding. The main types of natural bait are freshwater snails, earthworms and some insects. Large-scale breeding is supplemented by various animal blood, offal, freshwater fish, shrimp, shells and snails, as well as livestock compound feed and crop straw. A certain amount of wild snails or apple snails can be put into pond culture, usually about 0.05-0.1kg/square meter, to allow them to reproduce naturally and grow with leeches for their feeding. The number of snails should not be released too much. If too many snails are released, they will compete with the main species for living space, and the host and guest will change. When feeding animal blood or mixed bait, attention should be paid to feeding intervals and timely removal of leftover bait, especially when the weather is hot, to avoid contaminating and destroying water quality and affecting the growth of leeches.

2. Daily management. Leeches have very few diseases and mainly regulate water quality. Although leeches do not have strict requirements on the environment and water quality, if the water environment changes too much or deteriorates, their growth and reproduction will be affected. During the breeding process, the water temperature is generally maintained between 10-40°C. Breeding water that is overly fertilized and polluted must maintain a certain amount of dissolved oxygen. Generally, the dissolved oxygen in water bodies should be greater than 0.7 mg/L. If hypoxia occurs, small water bodies can be treated artificially To solve the problem of water spraying, larger water bodies should be promptly injected with new water or water should be changed. It is very important to maintain relatively fresh water quality during the high temperature season in summer.

5. Overwintering in Greenhouses

Due to regional influence, sunlight overwintering greenhouses under artificial conditions should be established in northern leech breeding to break their hibernation habits, increase breeding time, and shorten the market cycle. Solar greenhouses generally have a bamboo-wood-plastic thatch structure. The northern wall is made of earth or brick-concrete, 0.8-1.5m thick, oriented east-west, 30-50m long, 10-15m north-south span, and 5-7 rows of main columns. Cover it with drip-free plastic film and roll-up straw thatch, leaving doors, passages and air vents. During the severe cold and snowy season, snow removal and artificial warming measures should also be taken. Higher-end greenhouses can use plastic steel column-less methods, but the cost is relatively high.

By building a solar greenhouse, we can catch the large ones and leave the small ones in a planned way, and concentrate them over the winter. During the daily management, we should pay close attention to the temperature changes inside and outside the greenhouse, as well as oxygenation, wind protection, cold resistance, etc., to ensure the normal growth and development of leeches. Overwinter and prepare enough leech seeds for the following year.

6. Fishing and processing

1. Fishing methods: There are generally the following methods for harvesting leeches: (1) Fixed net fishing; (2) Drag net fishing; ( 3) Drainage fishing; (4) Mechanical fishing.

2. Processing method: (1) Lime burial method: mix the lime with the leech body, bury it for about 20 minutes, sun or dry it, and sieve out the remaining powder. (2) Water scalding method: Pour the newly boiled boiling water into a container where leeches are placed, cover and seal for 30 minutes, then remove and wash in water to dry. (3) Alkaline burning method: Stir the edible alkali powder into the leeches, or turn and rub them with your hands until they shrink to death, rinse with water and then dry in the sun. (4) Raw drying method: cross the leech with a thin wire and dry it in the sun.

7. Summary

As a famous and excellent breeding species, leech has the characteristics of fast growth, high yield, easy promotion, low investment, quick results, etc., and it can be introduced once and used for many years. Beneficial, suitable for urban and rural farming of various scales and methods. Under the current extreme shortage of natural leeches and the surge in market demand, it is imperative to develop artificial breeding. The benefits are obvious. It is a quick way to get rich for the majority of urban and rural people. It has great breeding prospects and development space. Source: "China Rural Science and Technology"

Construction of leech breeding ponds The construction of leech ponds depends on the size of the farmer's investment to determine the mode of the breeding pond, which is generally divided into two types: small breeding ponds and large breeding ponds< /p>

① The construction of small breeding ponds generally involves constructing a pond trench with a width of 3 meters and a depth of 1 meter, and the length is not limited. You can also build a number of small pools with hard walls and ridges 40 cm wide. Each pool is equipped with an outlet and an inlet. There must be a 50-100 cm wide spawning platform in the middle of the pool. The platform is on the same level as the water surface. A layer of 20 cm thick humus soil is piled on the platform. As a place for leeches to lay eggs and reproduce. The water level is 50-60 cm.

②Construction of large-scale breeding ponds The construction of large-scale breeding ponds is generally based on the actual geographical environment and the construction of ponds of different specifications. If the water source is not convenient, you can also put a layer of plastic film on the bottom of the pool. An appropriate amount of river mud should be placed at the bottom of the pool to increase the organic matter content of the water. Planting some aquatic plants in the water can purify the water quality and increase the oxygen content in the water. It is best to bury a circle of nylon mesh (0.5-0.6 meters high) on the bank of the pond to prevent natural enemies such as frogs and snakes from entering the breeding pond. In order to prevent the water temperature from being too high and the light from being too strong in summer, weeping willows and other trees can be planted on the bank of the pool to provide shade.

Reproduction of leeches Leeches are hermaphrodites, cross-fertilized, and each mature leech has the ability to reproduce. Although leeches are hermaphrodites, they must undergo cross-fertilization to reproduce. Leech mating is usually carried out under 1-2.5 cm small rocks, debris or moist soil. When mating, the head ends of the two leeches are in opposite directions, and their male and female genitals are exactly facing the other's female orifice. Egg laying begins one month after mating. The production period is from mid-April to early August, and the average temperature is between 19-24°C. After the cocoon is laid, the young leech emerges from the egg in 16-25 days. In the case of artificial breeding, it is necessary to improve the reproductive survival rate of leeches, select the egg cocoons, and place them in a suitable environment to concentrate the eggs. What issues should be paid attention to when raising and managing leeches? The following issues should be paid attention to when raising and managing leeches:

① Water quality requires fertilizer, liveliness, clarity, and sufficient oxygen content. If water quality deteriorates, clean water should be replaced gradually and promptly.

② Feeding. During the seedling stage, from mid-April to late May every year, pig blood or cow blood is sprinkled on the water surface for the young leeches to suck. Young leeches and seed leeches can feed live river mussels or field snails for the water leeches to suck.

③Water temperature. The water temperature should be maintained at 15-25°C. Stop feeding when it is lower than 10°C. When it is higher than 30°C, it is not conducive to the growth and development of leeches.

④Prevent and control pesticides, chemical fertilizers and water pollution. It is best not to have pesticides and chemical fertilizers around the leech pond. At the same time, no domestic sewage or organic wastewater should penetrate or be discharged into the breeding pond.

⑤ Maintain the tidal temperature of the soil on the spawning platform in the pool to prevent drying and create good conditions for the breeding of leeches.

⑥Prevent leeches from freezing damage during the overwintering period. Leeches mostly overwinter in shallow soil or under dead grass leaves, and are easily killed by freezing in sudden cold weather. Therefore, during the winter, add some grass thatch or corn straws near the water near the pond.

How to manage leech hatching? During the leech hatching stage, try to avoid walking on the platform to avoid stepping on the egg cocoon. The platform surface should be kept moist and can be covered with a layer of aquatic plants. If it rains, the overflow outlet should be dredged. The water surface should not cover the platform, and a gap of 3-5 cm should be maintained. Young leeches mainly rely on egg yolk to survive 2 or 3 days after hatching, and feed after 3 days. The newly hatched young leeches mainly feed on the blood and juice of clams and snails, and the entire soft body of a clam and snail. Young leeches are produced rapidly.

How to catch and process leeches? Use straw and other straw crops to tie into small bundles, soak them in livestock food and put them into the pond. After smelling the leeches, they will gather on the straw bundles and take them out. You can mix cigarette shreds and water together and put them in a basin. , put the leech into the basin. If the leech becomes dead in about ten minutes, take it out immediately. Just dry it naturally. It can be buried with lime for 20 minutes and then taken out to dry in the sun after it dies. The dried leech should be clean and tidy with no impurities. The whole leech should be naturally flat, the head should be raised, the texture should be brittle and easy to break, and the cross section should be gelatinous and shiny. most.