Ricefield eel breeding technology

Abstract

The invention provides a ricefield eel breeding technology, which relates to the technical field of ricefield eel breeding, and comprises the following steps: step 1, parent selection and anesthesia; step 2, parent spawning induction; step 3, fry incubation; step 4, temporary culture of seedlings in a constant-temperature workshop. According to the ricefield eel breeding technology, healthy male ricefield eels and healthy female ricefield eels are selected as male parents and female parents respectively, sperms are taken from the male parents, ova are taken from the female parents, in this way, defective ricefield eel sperms and ricefield eel ova are greatly reduced, and then the ricefield eel ova and ricefield eel sperms are combined in an in-vitro fertilization mode; due to the fact that the monopterus albus eggs and the monopterus albus sperms are concentrated together, fertilization of all the eggs can be completed, the fertilized eggs after fertilization are artificially cultivated and formed, the hatching rate is high, the cultivated monopterus albus fries are healthy, and the monopterus albus fries can grow healthily.

Description

Technical Field

[0001] The invention relates to the technical field of yellow eel breeding, in particular to a yellow eel breeding technology. Background Art

[0002] During the development of the eel farming industry, there is a severe shortage of seedlings, and the seedlings currently released are mainly wild eel seedlings. Breeding wild eel seedlings has the problem of low survival rate in production, and the quantity cannot meet the requirements of the rapid development of the eel industry.

[0003] The breeding season of yellow eels is mainly from May to August each year, with June being the peak spawning period. Yellow eels usually choose to build nests on the edge of the water, with the hole opening in a hidden place and the lower edge of the hole submerged in water. The breeding hole is divided into a front hole and a back hole. The front hole is used for laying eggs, and the back hole is slender but wider. During the breeding season, male and female yellow eels will build nests together. The female eel will spit out foam to build a nest and lay eggs on the foam. The male eel will ejaculate on the eggs to complete in vitro fertilization. Since there is no human intervention, the fertilization process is completely random. According to studies, the breeding success rate of wild yellow eels is usually only about 5% to 10%, so relying on the yellow eel's own way of reproduction cannot meet market demand. To this end, we propose a yellow eel breeding technology. Summary of the Invention

[0004] The present invention provides a yellow eel breeding technology, which has the advantages of high hatching rate and large-scale breeding and cultivation of yellow eel seedlings, and solves the problems raised in the above-mentioned background technology.

[0005] The technical solution of the present invention is achieved as follows: a yellow eel breeding technology is designed, comprising the following steps: Step 1: Parent selection and anesthesia 1) Initial screening: First, screen the parents. Select well-developed female parents with swollen and soft abdomens. You can feel the presence of eggs in the abdomen of the eel by touching it. The eggs should not be too few or overripe. 2) Anesthesia: Divide the parents equally into a plastic box and anesthetize them with anesthetic for 5-10 minutes; 3) Fine screening: After the parents are anesthetized, a second round of precise screening is performed to select qualified parents for induced labor. Gently touch the abdomen of the parents. The qualified parents are those with obvious granularity, plump eggs, and no injuries or diseases. Step 2: Parental Induction 1) Injection of oxytocin: After screening qualified parents, the qualified parents are injected with oxytocin according to their weight; 2) Parents are temporarily raised for induced labor: the parents that have been injected with induced labor drugs are placed in boxes and trays in a constant temperature workshop for temporary raising; 3) Sperm collection: Select a male parent with good vitality, cut off the spine of the male eel's head, open the abdominal cavity with a scalpel, remove the intact testis, and squeeze it into a centrifuge tube containing sperm preservation solution; 4) Semen microscopy: Observe the motility and concentration of sperm in the preservation solution under a microscope. The criterion is that if there are a large number of motile sperm in the field of view, the sperm can be used for fertilization. 5) Egg retrieval and fertilization: Add 4ml of fertilization nutrient solution and 1000μL of semen to a porcelain bowl. Use a pipette tip to clear the female parent's reproductive pore. The mature eggs will flow naturally and smoothly into the porcelain bowl filled with nutrient solution and semen. Gently shake the eggs, nutrient solution and semen to evenly mix them. Fertilization will take 8-10 minutes. Step 3: Seedling incubation 1) Egg membrane hardening: Transfer the eggs to the incubation frame of the breeding rack, turn on the tap, and keep the water flowing slowly to ensure sufficient exchange area between the eggs and the water. After the fertilized eggs absorb water, the eggs will gradually harden. 2) Egg Bucket Development: The hardened eggs are transferred into the bucket. Driven by the reduction motor, the incubation bucket slowly rises and quickly drops, allowing the fertilized eggs to continuously suspend and settle in the water, ensuring sufficient dissolved oxygen, preventing the fertilized eggs from clumping and mold, and promoting embryonic development. 3) Seedling emergence and development: After the eggs in the bucket develop for 7-8 days, black eel larvae can be seen in the eggs. The fertilized eggs are transferred to the breeding rack and the seedlings gradually emerge from the second day. The seedlings do not need to be fed after emerging from the membrane, as their own yolk can provide nutrition. After 7-10 days, the yolk gradually disappears and the seedlings turn black. At this time, the seedlings can be removed from the rack and transferred to the breeding workshop for cultivation; Step 4: Temporarily raise the seedlings in a constant temperature workshop.

[0006] Preferably, in step 3), unfertilized yellow eggs and whitish and turbid bad eggs are prone to mold growth and infect mature fertilized eggs, and the unfertilized eggs need to be picked out in time with a straw.

[0007] Preferably, in step four, water quality management is first carried out. The water must first be fully exposed to the sun, oxygenated, and precipitated in an outdoor water tank to remove impurities with high content of ammonia nitrogen, sediment, iron, etc., and then heated by heat conduction before flowing into the seedling cultivation pool in the workshop for use. The water temperature of the indoor seedling cultivation pool is controlled at 31.5±1.5℃.

[0008] The preferred method is feeding management, which involves feeding red worms by drip method for half a month during the initial stage of training.

[0009] Preferably, the eel fry are fed on the third day after entering the pond, and are fed one meal every two days. The feeding amount is increased after every two meals, and 0.5 liang of bloodworms are added each time, and finally the feeding amount of bloodworms is controlled within 0.5 liang per 100 fry.

[0010] Preferably, the water in the seedling cultivation pond needs to be changed every 3-5 days to keep the water fresh and free of dirt accumulation at the bottom.

[0011] Preferably, in step 3) of step 2, a 50ml centrifuge tube is selected, and the sperm preservation solution is about 45ml. A 50ml centrifuge tube can store sperm from about 5 male eels.

[0012] Preferably, in step 2) of step 1, the anesthetic is MS-222 anesthetic.

[0013] Preferably, when the external water temperature does not exceed 28°C, the seedlings are not directly put into the fish pond.

[0014] Compared with the existing technology, the yellow eel breeding technology proposed by the present invention selects healthy male and female yellow eels as male parents and female parents respectively, extracts sperm from the male parent, and extracts eggs from the female parent, thus greatly reducing the defective yellow eel sperm and yellow eel eggs, and then allows the yellow eel eggs and yellow eel sperm to be combined through in vitro fertilization. Since the yellow eel eggs and yellow eel sperm are concentrated together, all eggs can be fertilized. The fertilized eggs are then artificially cultivated and formed, with a high hatching rate, and the cultivated yellow eel seedlings are all healthy, so that the yellow eel seedlings can all grow healthily. DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0016] The present invention specifically adopts the following method for breeding yellow eel, which includes five steps. Steps 1 to 3 are the process of fertilizing the egg particles, and steps 4 and 5 are the process of cultivating the egg particles. The steps are as follows: Step 1: Parent selection and anesthesia 1) Initial screening: Before the operation, operators should wear gloves to protect the eels and prevent their hands from slipping. During the operation, the parents should be screened first. Well-developed female parents should be selected with swollen and soft abdomens. The presence of eggs can be felt by touching the abdomen of the eels. The eggs should not be too few or over-ripe to avoid defects in the selected parents. 2) Anesthesia: Divide the parents into a plastic box and anesthetize them with anesthetic for 5-10 minutes. The anesthetic used is MS-222. In the actual operation, it is necessary to correctly control the anesthesia time. It should be noted that 5-10 minutes is not a specific value. In the actual operation, stop when the eel is anesthetized and can no longer move, to avoid suffocation caused by long anesthesia time. 3) Fine screening: After the parents are anesthetized, a second round of precise screening is performed to further select good parents. This is an important step to increase the subsequent survival rate. Qualified parents are selected for induced spawning. As in step 1), gently touch the abdomen of the parent. The parent with obvious granularity, plump eggs, and no injuries or diseases is a qualified parent. The movement should be gentle during this process, and the force of moving the hand along the eel should be moderate; Step 2: Parental Induction 1) Injection of oxytocin: After screening qualified parents, the qualified parents are injected with oxytocin according to their weight. The injection operation requires the use of strictly sterilized syringes and needles. The injection site is usually the body cavity or intramuscular. When injecting into the body cavity, the needle is inserted at a 45-degree angle to the front abdomen of the eel. 2) Parents are temporarily raised for induced spawning: The parents that have been injected with induced spawning drugs are placed in a box tray in a constant temperature workshop for temporary raising. This process is used to wait for the eels to wake up. The eels' condition must be observed at all times. If any eels are found to be in poor condition, they need to be picked out and raised separately or the parent eels need to be removed for raising; 3) Sperm collection: Select a male parent with good vitality, cut the spine of the male eel's head, so as to directly cut off the nerve connection between the head and the body, and prevent it from swinging. Then use a scalpel to cut open the abdominal cavity, remove the intact testis, and squeeze it into a centrifuge tube. The centrifuge tube contains sperm preservation solution. Use a 50ml centrifuge tube with about 45ml of sperm preservation solution. A 50ml centrifuge tube can store sperm from about 5 male eels. 4) Semen microscopic examination: Observe the motility and concentration of sperm in the preservation solution under a microscope. The criterion is the presence of a large number of motile sperm within the field of view. Good motility indicates that the sperm can be used for fertilization. In addition to the fine screening in step 3) above, selecting motile and motile sperm is also key to ensuring the survival rate of the seedlings. 5) Egg retrieval and fertilization: Add 4ml of fertilization nutrient solution and 1000μL of semen to a porcelain bowl (any container will do). Use a pipette tip to clear the female parent's reproductive pore. The mature eggs will flow naturally and smoothly into the porcelain bowl filled with nutrient solution and semen. Gently shake the eggs, nutrient solution and semen evenly. Fertilize for 8-10 minutes to allow full contact between the eggs and semen to ensure that every egg can be fertilized. Because the eggs and semen are carefully selected, fertilization can greatly increase the reproduction rate. Step 3: Seedling incubation 1) Egg membrane hardening: Transfer the eggs to the incubation frame of the breeding rack, turn on the tap, and keep the water flowing slowly to ensure sufficient exchange area between the eggs and the water. After the fertilized eggs absorb water, the eggs gradually harden. Turning on the tap is to keep the water in the incubation frame flowing. This not only flushes away debris around the eggs, but also increases the oxygen content in the water. 2) Egg Bucket Development: The hardened eggs are transferred into the bucket. Driven by the reduction motor, the incubation bucket slowly rises and quickly drops, allowing the fertilized eggs to continuously suspend and settle in the water to ensure sufficient dissolved oxygen. Since each egg can obtain sufficient oxygen, this can prevent the fertilized eggs from clumping and mold, and promote embryonic development. 3) Seedling emergence and development: After the eggs in the bucket develop for 7-8 days, black eel larvae can be seen in the eggs. At this time, the eel larvae can be found, just like black lines appearing in the transparent shell. Unfertilized yellow eggs and whitish and turbid bad eggs are prone to mold and infect mature fertilized eggs. Unfertilized eggs must be picked out with a straw in time. When eel larvae appear, be sure to observe the larvae in time and pick out undeveloped eggs in time to prevent the eel larvae from being infected by pathogens. From the second day after the fertilized eggs are transferred to the breeding rack, the seedlings gradually emerge from the membrane. After emerging from the membrane, the seedlings do not need to be fed. Their own yolk can provide nutrition. The yolk can be the yolk of chicken eggs, duck eggs or goose eggs. After the eggs are cooked, the yolks are taken out, crushed and then quantitatively put into water for the larvae to eat. After 7-10 days of the seedlings emerging from the membrane, the yolk gradually disappears and the seedlings turn black. At this time, the seedlings can be taken off the shelf and transferred to the breeding workshop for cultivation. At this time, the seedlings have a certain ability to resist the environment; Step 4: Temporary cultivation of seedlings in a constant temperature workshop First, water quality management is carried out. The water must first be fully exposed to the sun, oxygenated, and precipitated in outdoor water tanks to remove impurities with high content of ammonia nitrogen, silt, iron, etc., and then heated by heat conduction and flowed into the workshop seedling cultivation pool for use. The water temperature in the indoor seedling cultivation pool is controlled at 31.5±1.5℃. This temperature must meet the growth requirements of seedlings. Both low and high temperatures will affect the growth and development of seedlings. Therefore, water temperature control during the seedling period is key. The second is feeding management. At this time, there is no need to feed egg yolks because the seedlings can eat on their own. For the convenience of eating, you can choose small and beneficial foods for the eels. For example, in the first half month of taming, use the drip method to feed bloodworms. The size of the bloodworms is just right for the seedlings to eat and is nutritious. Feeding starts on the third day after the eel seedlings enter the pond. Feed once every two days. Increase the feeding amount after every two meals, and increase 0.5 liang of bloodworms each time. Finally, control the feeding of bloodworms within 0.5 liang for every 100 seedlings. It should be noted that the amount of worms should not be too much. Too much will cause the seedlings to eat too much and lead to overnutrition. The amount of worms should not be too little. This will lead to insufficient nutrition for the seedlings. Therefore, the correct amount of worms must be stably controlled so that the seedlings can grow quickly. During the cultivation process, the water in the seedling pond needs to be changed every 3-5 days to keep the water fresh and free of dirt accumulation at the bottom.

[0017] Based on the above steps, it should be noted that in the actual operation of the present invention, when the seedlings are mature, they should be placed in the pond at the right time. Because the breeding of yellow eels begins in April, the first batch of seedlings can be taken out of the breeding workshop in early May. During this period, the outdoor climate is still unstable and the water temperature is below 28°C. The seedlings cannot be directly placed in the fish pond and need to be temporarily kept in a constant temperature.

[0018] Next, we will sample the fertilized eggs from step 5) of step 2 to prepare observation samples, and analyze the fertilized egg cultivation process of different samples: 1. Take 10 samples of the fertilized eggs from step 5) of step 2, namely sample 1 to sample 10, with 100 fertilized eggs in each sample. Place samples 1 to 10 in air-permeable and water-permeable culture containers. Secure the six containers in the incubation bucket. It should be noted that the culture containers will not allow the fertilized eggs to leak out. 2. The incubation process is the same as the seedling incubation process in step 3. First, turn on the tap and keep the water flowing slowly to ensure sufficient exchange area between the eggs and the water. After the fertilized eggs absorb water, the eggs gradually harden. Secondly, the hatching bucket is driven by the reduction motor, slowly rising and falling, allowing the fertilized eggs to continuously suspend and settle in the water, ensuring sufficient dissolved oxygen, preventing the fertilized eggs from agglomerating and moldy, and promoting embryonic development; Then, when the eggs in the bucket develop for 7-8 days, and black eel larvae are visible in the eggs, the cultivation of the samples can be stopped; 3. Samples 1 to 10 were sorted separately. The sorting process was to remove unfertilized yolk eggs and whitish and turbid bad eggs in each sample. Then, samples 1 to 10 were counted one by one. The statistics are shown in the following table:

[0019] It can be seen from the contents of the above table that the survival rate of eel seedlings hatched using the fertilized eggs provided by the present invention is high. The survival rate of fertilized eggs cultivated by this method is generally above 95%, which greatly improves the hatching rate compared with the natural fertilization and hatching of eels.

[0020] 4. Temporarily raise the seedlings of Samples 1 to 10 separately. The cultivation process is to culture Samples 1 to 10 separately according to the method in Step 4, that is, the water temperature of the indoor seedling cultivation pond is controlled at 31.5±1.5℃, and the eel seedlings are fed starting from the third day after entering the pond, with one meal every two days. The feeding amount is increased after every two meals, and the feeding amount is controlled to be within 0.5 liang of bloodworms per 100 seedlings; The seedlings from samples 1 to 10 were cultured for ten days. The seedlings were observed daily and debris was removed from each sample to ensure a good growth environment. The specific conditions after ten days are shown in the following table:

[0021] It can be seen from the above table that after ten days of breeding, the state of the eel seedlings has basically stabilized. Although the survival rate is lower than the hatching rate, the overall survival rate is generally above 95%, which greatly improves the survival rate compared with the natural fertilization and reproduction of eels.

[0022] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A yellow eel breeding technology, characterized in that: The steps include: Step 1: Parent selection and anesthesia 1) Initial screening: First, screen the parents. Select well-developed female parents with swollen and soft abdomens. You can feel the presence of eggs in the abdomen of the eel by touching it. The eggs should not be too few or overripe. 2) Anesthesia: Divide the parents equally into a plastic box and anesthetize them with anesthetic for 5-10 minutes; 3) Fine screening: After the parents are anesthetized, a second round of precise screening is performed to select qualified parents for induced labor. Gently touch the abdomen of the parents. The qualified parents are those with obvious granularity, plump eggs, and no injuries or diseases. Step 2: Parental Induction 1) Injection of oxytocin: After screening qualified parents, the qualified parents are injected with oxytocin according to their weight; 2) Parents are temporarily raised for induced labor: the parents that have been injected with induced labor drugs are placed in boxes and trays in a constant temperature workshop for temporary raising; 3) Sperm collection: Select a male parent with good vitality, cut off the spine of the male eel's head, open the abdominal cavity with a scalpel, remove the intact testis, and squeeze it into a centrifuge tube containing sperm preservation solution; 4) Semen microscopy: Observe the motility and concentration of sperm in the preservation solution under a microscope. The criterion is that if there are a large number of motile sperm in the field of view, the sperm can be used for fertilization. 5) Egg retrieval and fertilization: Add 4ml of fertilization nutrient solution and 1000μL of semen to a porcelain bowl. Use a pipette tip to clear the female parent's reproductive pore. The mature eggs will flow naturally and smoothly into the porcelain bowl filled with nutrient solution and semen. Gently shake the eggs, nutrient solution and semen to evenly mix them. Fertilization will take 8-10 minutes. Step 3: Seedling hatching 1) Egg membrane hardening: Transfer the eggs to the incubation frame of the breeding rack, turn on the tap, and keep the water flowing slowly to ensure sufficient exchange area between the eggs and the water. After the fertilized eggs absorb water, the eggs will gradually harden. 2) Egg Bucket Development: The hardened eggs are transferred into the bucket. Driven by the reduction motor, the incubation bucket slowly rises and quickly drops, allowing the fertilized eggs to continuously suspend and settle in the water, ensuring sufficient dissolved oxygen, preventing the fertilized eggs from clumping and mold, and promoting embryonic development. 3) Seedling emergence and development: After the eggs in the bucket develop for 7-8 days, black eel larvae can be seen in the eggs. The fertilized eggs are transferred to the breeding rack and the seedlings gradually emerge from the second day. The seedlings do not need to be fed after emerging from the membrane, as their own yolk can provide nutrition. After 7-10 days, the yolk gradually disappears and the seedlings turn black. At this time, the seedlings can be removed from the rack and transferred to the breeding workshop for cultivation; Step 4: Temporarily raise the seedlings in a constant temperature workshop.

2. The eel breeding technology according to claim 1, wherein: In step 3) of step 3, unfertilized yellow eggs and whitish and turbid bad eggs are prone to mold growth and infect mature fertilized eggs. Unfertilized eggs need to be picked out in time with a straw.

3. The eel breeding technology according to claim 1, wherein: In step four, water quality management is first carried out. The water must first be fully exposed to the sun, oxygenated, and precipitated in an outdoor water tank to remove impurities with high content of ammonia nitrogen, silt, iron, etc., and then heated by heat conduction before flowing into the seedling cultivation pool in the workshop for use. The water temperature of the indoor seedling cultivation pool is controlled at 31.5±1.5℃.

4. The eel breeding technology according to claim 3, wherein: The second is feeding management. In the first half month of training, feed red worms using the drip method.

5. The eel breeding technology according to claim 4, wherein: Start feeding the eel fry on the third day after they enter the pond, feed them one meal every two days, increase the feeding amount after every two meals, and increase 0.5 liang of bloodworms each time, and finally control the feeding amount within 0.5 liang of bloodworms for every 100 fry.

6. The eel breeding technology according to claim 3, wherein: The water in the seedling cultivation pond needs to be changed every 3-5 days to keep the water fresh and free of dirt accumulation at the bottom.

7. The eel breeding technology according to claim 1, wherein: In step 3) of step 2, use a 50ml centrifuge tube with about 45ml of sperm preservation solution. A 50ml centrifuge tube can store sperm from about 5 male eels.

8. The eel breeding technology according to claim 1, wherein: In step 2) of step 1, MS-222 anesthetic is used as the anesthetic.

9. The eel breeding technology according to claim 3, wherein: When the outside water temperature does not exceed 28℃, the seedlings should not be put directly into the fish pond.

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