A Cultivation Method of Hybrid Spiny Eels

Abstract

The present invention provides a method for cultivating hybrid spiny eels, which method comprises: S1. Selection of parent fish; S2. Inducing spawning and fertilization; S3. Culturing fry; and S4. Culturing commercial fish. This cultivation method uses Sinobdella sinensis and Macrognathus aculeatus for hybridization. It can either use male Sinobdella sinensis as the male parent and female Macrognathus aculeatus as the female parent for hybridization and breeding, or use male Macrognathus aculeatus as the male parent and female Sinobdella sinensis as the female parent for hybridization and breeding, and can obtain a population of offspring with the hybrid advantages of the parents in a short time, improving the problems of poor cold tolerance and population degradation of Macrognathus aculeatus itself.

Description

Technical Field

[0001] The present invention relates to the technical field of freshwater fish farming, and in particular to a method for cultivating hybrid spiny eels. Background Art

[0002] The large spiny eel (Mastacembelus armatus), commonly known as knife cut, knife eel, that mouth, etc., belongs to the order Perciformes, family Mastacembelidae, genus Mastacembelus, and generally inhabits shallow water areas with abundant aquatic plants. The flesh of the large spiny eel has a good taste and high nutritional value, and has gradually become a high-grade freshwater artificial breeding variety.

[0003] With the expansion of the breeding scale of the large spiny eel, there have also emerged some defects that limit the large-scale promotion and breeding of this variety, such as population degradation, low survival rate of fry, and poor cold tolerance.

[0004] The prior art discloses an artificial intensive hatching method for fry of the Zengjiang large spiny eel, including the following specific steps: S1. Inject the ovulation hormone DOM and chorionic gonadotropin into the selected parent eels; S2. Put the parent eels obtained in S1 into a hybridization pond and flush with water to stimulate until the parent eels are in heat and lay eggs; S3. Mix the collected fish eggs and semen and put them into physiological saline for fertilization; S4. Use a brush to attach the fertilized eggs to an artificial fish nest and put them into an incubation box in an incubation pond for incubation. The hatching method can improve the survival rate of fry to a certain extent, but the problems of cold tolerance and population degradation still cannot be solved.

[0005] Therefore, it is necessary to improve the current feeding dilemma of the large spiny eel through cross-breeding. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention provides a method for cultivating hybrid spiny eels. By crossing the Chinese spiny eel with the large spiny eel, offspring populations with parental hybrid advantages can be obtained in a short time, and the problems of poor cold tolerance and population degradation of the large spiny eel itself can be improved.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for cultivating hybrid spiny eels, comprising the following steps:

[0009] S1. Selection of parent eels: Select the Chinese spiny eel and the large spiny eel as the parent eels for breeding. The weight of the selected parent eels should be 20-30% greater than the median weight of the same batch and the same sex.

[0010] S2. Inducing spawning and fertilization: Transfer the selected broodstock into the spawning pond, maintain the water temperature at 28 - 30 °C to enable the broodstock to reach the optimal physiological state before spawning; after injecting the spawning-inducing drugs, collect eggs and semen respectively; pour the diluted semen into the container containing eggs, and fully mix the semen and eggs to complete fertilization;

[0011] S3. Larval rearing: After the larvae hatch and the yolk sac is completely absorbed, they can be fed with the first feed, and fed three times a day; gradually add commercial feed as the larvae grow;

[0012] S4. Commercial fish farming: When the larvae grow to 4 - 5 cm, transfer them to the pond for farming; feed them twice a day according to the "three fixed" principle.

[0013] Among them, the Chinese spiny eel (Sinobdella sinensis) belongs to the genus Sinobdella of the family Mastacembelidae in the order Perciformes, and is a small freshwater fish widely distributed in the southeastern region of China. The Chinese spiny eel is closely related to the large spiny eel, and the Chinese spiny eel has a higher latitude of the growth environment, so it has better cold tolerance.

[0014] The present invention adopts a method of cross-breeding the Chinese spiny eel and the large spiny eel, and can obtain a population of offspring with the hybrid advantages of the parents in a short time. The hybrid offspring of the Chinese spiny eel and the large spiny eel can improve the feeding dilemma that the large spiny eel cannot be farmed in the north and the Chinese spiny eel cannot be farmed in the south, filling the gap in the breeding technology of hybrid spiny eels. The hybrid offspring of the Chinese spiny eel and the large spiny eel obtained by cultivation not only maintain good fish meat quality and taste, but also have excellent cold tolerance, effectively solving the problem of population degradation of the large spiny eel and expanding the suitable farming range.

[0015] As a further description of the technical solution of the present invention, in the step S1, the selection of the Chinese spiny eel and the large spiny eel as the broodstock for breeding specifically includes:

[0016] Select the male Chinese spiny eel and the female large spiny eel as the broodstock for breeding. Among them, the male Chinese spiny eel has bright body patterns, a slender body shape and a relatively hard abdomen, and its weight should be greater than 18 g;

[0017] The female large spiny eel has a yellowish-brown body color, a thick and short body shape, a swollen and soft abdomen with good elasticity when touched, and its weight should be greater than 160 g.

[0018] As a further description of the technical solution of the present invention, in the step S1, the selection of the Chinese spiny eel and the large spiny eel as the broodstock for breeding specifically includes:

[0019] Select the female Chinese spiny eel and the male large spiny eel as the broodstock for breeding. Among them, the weight of the female Chinese spiny eel should be greater than 16 g, and the weight of the male large spiny eel should be greater than 220 g.

[0020] As a further description of the technical solution of the present invention, in the step S1, broodstock selection should be carried out before the breeding season in March and April each year, and both male and female broodstock should have uniform and correct body shape, no surface deformities, no injuries, and normal feeding; male broodstock should be selected from larger individuals in the pond, and it is appropriate to squeeze the abdomen to have semen overflow; female broodstock should be selected from larger individuals with swollen abdomen and well-developed gonads, and the selected broodstock should be raised in a temporary holding pond.

[0021] As a further description of the technical solution of the present invention, in the step S2, the oxytocin drugs include human chorionic gonadotropin HCG, luteinizing releasing hormone LRH-A2, and dioestrogen DOM, which are evenly mixed before injection at the following dosage ratio of HCG 800-1200 IU / kg, LRH-A2 8-12 μg / kg, and DOM 4-6 mg / kg.

[0022] As a further description of the technical solution of the present invention, the mixed oxytocin drug is diluted 10 times with sterile injection saline, and the female broodstock is injected with 10 mL / kg each time. The second injection is performed 12 hours after the first injection, and the second dose is halved;

[0023] Take the mixed oxytocin drug, do not dilute it, and inject the male broodstock only once, the injection time is the same as the second injection time of the female broodstock, and the injection dose is 0.5mL / kg;

[0024] After the injection, the broodstock are returned to the birthing pool to wait for the induced labor drugs to take effect.

[0025] As a further description of the technical solution of the present invention, the fertilization of S2 is wet fertilization, and before collecting eggs and semen, the parent fish needs to be anesthetized using fish anesthetic MS-222;

[0026] Egg collection: Wrap the anesthetized female broodstock with a wet towel, lie on the side with the cloaca facing one side, and slowly massage and squeeze the abdomen from front to back to make the eggs flow into the clean container prepared in advance. After squeezing the eggs, put the female broodstock into clean water for aeration to wake it up from the anesthesia;

[0027] Semen collection: Wrap the anesthetized male broodstock with a wet towel, lay it on its side with its cloaca close to the prepared container, and slowly squeeze its abdomen to make the semen flow into the container. After the semen is collected, add sterilized saline and mix thoroughly; put the male broodstock into clean water for aeration to wake it up from the anesthesia;

[0028] Fertilization of fish eggs: slowly pour the diluted semen into the container containing eggs, and pour the two containers back and forth to fully mix the semen and eggs to complete fertilization;

[0029] After the fish eggs are fertilized, they are hatched. The temperature of the hatching environment is not lower than 27 °C, and the dissolved oxygen is not lower than 5 mg / L.

[0030] As a further description of the technical solution of the present invention, in the S3 fry cultivation, the initial feed is cooked egg yolk or rotifers, and feeding is carried out three times at 6:00, 14:00, and 22:00 every day; invertebrates are added in the middle stage, and commercial feed is gradually added and replaced in the later stage.

[0031] As a further description of the technical solution of the present invention, in the S4 commercial fish farming, the fry are stocked in the pond at a stocking density of 4000 - 4500 tails / mu, and sufficient fish nests or PVC pipes should be arranged in the pond in advance as shelters; commercial Macrognathus aculeatus feed is fed twice at 7:00 and 18:00 every day.

[0032] As a further description of the technical solution of the present invention, the construction specifications of the temporary rearing pond are a 2 * 10 m cement pond with a water depth of 50 cm, and the bottom and walls of the pond should be covered with smooth tiles. PVC pipes or fish nests are arranged at the bottom of the pond for breeding parent fish to hide, and the oxygen content in the water is not lower than 5 mg / L; during the feeding process of the parent fish in the temporary rearing pond, commercial Macrognathus aculeatus feed added with 20% fresh fish and shrimp minced meat is fed twice at 7:00 and 18:00 every day.

[0033] Based on the above technical solution, compared with the prior art, the technical effects achieved by the present invention are as follows:

[0034] (1) The cultivation method of the hybrid Macrognathus aculeatus provided by the present invention includes the specific steps of parent fish selection, induced spawning and fertilization, and fry cultivation and commercial fish farming. Among them, the standards and requirements for the parent fish used in the cultivation process of the hybrid Macrognathus aculeatus are elaborated in the parent fish selection; this cultivation method can either use male Sinobdella sinensis as the male parent and female Macrognathus aculeatus as the female parent for cross-breeding, or use male Macrognathus aculeatus as the male parent and female Sinobdella sinensis as the female parent for cross-breeding, so as to obtain a population of offspring with the hybrid advantages of the parents in a short time, and improve the problems of poor cold tolerance and population degradation of Macrognathus aculeatus itself.

[0035] (2) The cultivation method of the hybrid Macrognathus aculeatus of the present invention first proposed the concept of cross-breeding between Sinobdella sinensis and Macrognathus aculeatus, and clarified the feeding management operations of artificial induced spawning, fry cultivation and commercial fish farming in the cross-breeding process, and developed a set of operating procedures suitable for the production and cultivation of hybrid Macrognathus aculeatus, introduced improved varieties for the development of Macrognathus aculeatus farming, promoted the variety upgrade of the hybrid Macrognathus aculeatus aquaculture industry, and increased the output value of the aquaculture industry. Detailed implementation mode

[0036] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. The preferred embodiments of the present invention are given in the embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0038] Example 1

[0039] A method for the reciprocal cross-breeding of hybrid spiny eels, comprising the following steps:

[0040] S1. Selection of broodstock: Select Macrognathus sinensis and Mastacembelus armatus with regular body shape, strong constitution, no diseases or injuries, normal body color, complete fin rays, a lot of body mucus, and stable breeding for more than half a year by naked eyes as the broodstock for reproduction. The weight of male Macrognathus sinensis should be greater than 18 g, and the weight of female Mastacembelus armatus should be greater than 160 g. The selected broodstock should preferably be selected to be 20-30% greater than the median weight of the same batch and the same sex.

[0041] Further screen the broodstock for reproduction. The ratio of female Mastacembelus armatus to male Macrognathus sinensis is 1:2. The selected male Macrognathus sinensis has bright body patterns, a slender body shape, a relatively hard abdomen, and it is appropriate that semen flows out when the abdomen is gently pressed; the selected female Mastacembelus armatus has a yellowish-brown body color, a thick and short body shape, a swollen and soft abdomen, good elasticity when touched, and a slightly red and protruding genital pore. Transfer the selected broodstock for reproduction to a temporary rearing pond for temporary rearing.

[0042] The temporary rearing pond is a cement pond with a bottom surface of 2 m * 10 m and the side walls covered with smooth ceramic tiles, equipped with temperature control and aeration devices, which can achieve a temperature control of 28 °C and a dissolved oxygen content of not less than 5 mg / L for 24 h. A fish nest or PVC pipe is laid at the bottom of the temporary rearing pond as a hiding nest for the broodstock. 20% fresh fish and shrimp mince is added to the commercial feed for Mastacembelus armatus as the daily feeding feed, and it is fed twice at 7:00 and 18:00 every day.

[0043] S2. Inducing spawning and fertilization: Transfer the prepared broodstock to the spawning pond, maintain the water temperature at 28-30 °C, preferably at a constant temperature of 28 °C, to make the broodstock reach the best pre-spawning physiological state. Mix the three inducing spawning drugs human chorionic gonadotropin HCG, luteinizing hormone-releasing hormone LRH-A2, and domperidone DOM in the following dosage ratio: HCG 800-1200 IU / kg, LRH-A2 8-12 μg / kg, DOM 4-6 mg / kg evenly. The injection dosage and frequency of the broodstock are as follows:

[0044] Female Mastacembelus armatus: 1 mL / kg, injected twice with a 12-hour interval between each injection.

[0045] Male Sinobdella sinensis: 0.5 mL / kg, injected simultaneously with the second injection of female Mastacembelus armatus broodstock.

[0046] After injection, the broodstock are returned to the spawning pool waiting for the oxytocic to take effect. The spawning pool is a cement pool with a bottom surface of 2m * 1m and the side walls fully covered with smooth ceramic tiles, equipped with temperature control and aeration devices, capable of achieving a temperature control of 28°C and a dissolved oxygen content of not less than 5 mg / L for 24 hours. There are fish nests or PVC pipes laid at the bottom of the spawning pool as shelters for the broodstock, and the broodstock are not fed during this period.

[0047] The hybridization fertilization method uses the wet fertilization method. Before collecting eggs and semen, it is necessary to anesthetize the broodstock with the fish anesthetic MS-222.

[0048] Semen collection: Wrap the body of the anesthetized male broodstock with a wet towel, lie it on its side so that its cloaca is close to a pre-prepared clean container (such as a stainless steel basin), slowly squeeze the abdomen to make the semen flow into the container. After the semen is collected, add sterilized normal saline for dilution, mix well and set aside; put the male broodstock into clear water for aeration to make it wake up from the anesthetized state.

[0049] Egg collection: Wrap the body of the anesthetized female broodstock with a wet towel, lie it on its side with the cloaca facing one side, slowly massage and squeeze the abdomen from front to back to make the eggs flow out into a pre-prepared clean container (such as a stainless steel basin). After squeezing the eggs, put the female broodstock into clear water for aeration to make it wake up from the anesthetized state.

[0050] Fertilization of fish eggs: Slowly pour the diluted semen into the container containing eggs, and pour the two containers back and forth to make the semen and eggs fully mixed to complete fertilization.

[0051] After the fish eggs are fertilized, transfer the fertilized eggs to the hatching pool for hatching, controlling the temperature of the hatching pool to be not less than 27°C and the dissolved oxygen to be not less than 5 mg / L. More specifically, the hatching pool is a cement pool with a bottom surface of 2m * 1m and the side walls fully covered with smooth ceramic tiles, equipped with temperature control and aeration devices, capable of achieving a temperature control of 28°C and a dissolved oxygen content of not less than 5 mg / L for 24 hours.

[0052] S3. Larval rearing and management: After the larvae hatch and the yolk sac is completely absorbed, they can be fed with the first feed. The first feed is selected as rotifers or cooked egg yolk water, and it is fed three times a day at 6:00, 14:00, and 22:00. Pay attention to the water quality changes during this period. As the larvae grow, commercial feed is continuously added during the feeding process, small invertebrates such as Tubifex are added in the middle stage, and the first feed is gradually changed to commercial feed for breeding to facilitate later breeding.

[0053] S4. Commercial fish farming: When the fry grow to 4 - 5 cm, the fry are stocked into the pond at a stocking density of 4000 - 4500 tails per mu. The depth of the fish pond should be greater than 1.5 m, and sufficient fish nests or PVC pipes should be arranged in advance in the pond as shelters. Silver carp and bighead carp are polycultured to control planktonic animals and plants in the water body. During the feeding period, pond patrol work should be done well to prevent abnormalities such as power failure of aquaculture facilities. At the same time, the expulsion of natural enemies such as birds and predatory fish should be done well. Feeding should follow the principle of "fixed time, fixed place, and fixed amount". Feed the commercial Mastacembelus aculeatus feed twice a day at 7:00 and 18:00. Check the feeding platform half an hour after feeding to determine the number of tails and feeding situation for the next time. In winter, in addition to natural overwintering, a greenhouse can also be used for overwintering to shorten the market time of commercial Mastacembelus aculeatus.

[0054] Example 2

[0055] An orthogonal cultivation method for hybrid Mastacembelus aculeatus includes the following steps:

[0056] S1. Selection of broodstock: During the breeding period from March to April, select Chinese spiny eels and large spiny eels with uniform body shape, no body surface deformities, normal feeding, a lot of body surface mucus, and stable feeding for more than half a year as the broodstock for breeding by naked eyes. The weight of male large spiny eels should be greater than 220 g, and the weight of female Chinese spiny eels should be greater than 16 g. The selected broodstock should preferably be selected 20 - 30% greater than the median weight of the same batch and the same sex.

[0057] Further screen the broodstock for breeding. The selected male large spiny eels should be the larger individuals in the pond, and it is appropriate that semen flows out when the abdomen is gently pressed. Small individuals should not be used except in special cases. The selected female Chinese spiny eels should be those with a larger body shape, a swollen abdomen, well-developed gonads, and a slightly red and protruding genital pore. Move the selected broodstock for breeding into the temporary rearing pond for temporary rearing.

[0058] The temporary rearing pond is a cement pond with a bottom of 2 m * 10 m, a water depth of 50 cm, and the side walls are covered with smooth ceramic tiles. It is equipped with temperature control and aeration devices, which can achieve a temperature control of 28°C, and the dissolved oxygen content is not less than 5 mg / L for 24 hours. Fish nests or PVC pipes are laid at the bottom of the temporary rearing pond as shelters for broodstock. Add 20% fresh fish and shrimp mince to the commercial Mastacembelus aculeatus feed as the daily feeding feed, and feed twice a day at 7:00 and 18:00.

[0059] S2. Inducing spawning and fertilization: Move the prepared broodstock into the spawning pond, maintain the water temperature at 28 - 30°C, preferably at a constant temperature of 28°C, to make the broodstock reach the best physiological state before spawning. Mix three inducing spawning drugs, human chorionic gonadotropin HCG, luteinizing hormone-releasing hormone LRH-A2, and domperidone DOM, in the following dosage ratio: HCG 800 - 1200 IU / kg, LRH-A2 8 - 12 μg / kg, DOM 4 - 6 mg / kg, and mix them evenly. The injection dosage and number of times for the broodstock are as follows:

[0060] Female Mastacembelus sinensis: Dilute 10 times with sterile injection saline, inject 10 mL / kg each time, and give the second injection 12 hours after the first injection, with the second dose halved;

[0061] Male Macrognathus aculeatus: Do not dilute before injection, the dose is 0.5 mL / kg, and inject simultaneously when the female Mastacembelus sinensis is given the second injection.

[0062] After injection, put the broodstock back into the spawning pool and wait for the oxytocic to take effect. The spawning pool is a cement pool with a bottom of 2m * 10m, a water depth of 50cm, and the side walls are fully covered with smooth ceramic tiles. It is equipped with temperature control and aeration devices, which can achieve a temperature control of 28°C, and the dissolved oxygen content is not less than 5mg / L for 24 hours. There are fish nests or PVC pipes laid at the bottom of the spawning pool as shelters for the broodstock, and the broodstock is not fed during this period.

[0063] The hybridization fertilization method adopts the wet fertilization method. Before collecting eggs and semen, it is necessary to anesthetize the broodstock with the fish anesthetic MS-222.

[0064] Egg collection: Wrap the body of the anesthetized female broodstock with a wet towel, lie on the side with the cloaca facing one side, slowly massage and squeeze the abdomen from front to back to make the eggs flow out into a previously prepared clean container (such as a stainless steel basin). After squeezing the eggs, put the female broodstock into clean water for aeration to make it wake up from the anesthetized state.

[0065] Semen collection: Wrap the body of the anesthetized male broodstock with a wet towel, lie on the side with the cloaca close to a previously prepared clean container (such as a stainless steel basin), slowly squeeze the abdomen to make the semen flow into the container. After collecting the semen, add sterilized saline for dilution, mix well and set aside; put the male broodstock into clean water for aeration to make it wake up from the anesthetized state.

[0066] Fertilization of fish eggs: Slowly pour the diluted semen into the container containing eggs, and pour the two containers back and forth to make the semen and eggs fully mixed to complete fertilization.

[0067] After the fish eggs are fertilized, transfer the fertilized eggs to the hatching pool for hatching, and control the temperature of the hatching pool not less than 27°C and the dissolved oxygen not less than 5mg / L. More specifically, the hatching pool is a cement pool with a bottom of 2m * 1m and the side walls are fully covered with smooth ceramic tiles. It is equipped with temperature control and aeration devices, which can achieve a temperature control of 28°C, and the dissolved oxygen content is not less than 5mg / L for 24 hours.

[0068] S3. Larval fish cultivation and management: After three days when the larval fish hatch and the yolk sac is completely absorbed, the initial feed can be provided. The initial feed can be rotifers or cooked egg yolk solution, which are fed three times a day at 6:00, 14:00, and 22:00. During this period, pay attention to the change of water quality. As the larval fish grow, commercial feed is continuously added during feeding. Small invertebrates such as tubifex worms are added in the middle stage, and the initial feed is gradually replaced with commercial feed for later cultivation.

[0069] S4. Commercial fish cultivation: When the larval fish grow to 5 cm, they are stocked in the pond at a stocking density of 4000 - 4500 tails per mu. The depth of the fishpond should be greater than 1.5 m, and sufficient fish nests or PVC pipes should be arranged in advance in the pond as shelters. Silver carp and bighead carp are polycultured to control the planktonic animals and plants in the water body. During the feeding period, pond patrol work should be done well to prevent abnormalities such as power failure of the breeding facilities. At the same time, work on driving away natural enemies such as birds and predatory fish should be done well. Feeding should follow the principle of "fixed time, fixed place, and fixed amount". Big spiny eel commercial feed is fed twice a day at 7:00 and 18:00. Check the feeding platform half an hour after feeding to determine the quantity and feeding situation for the next time. In winter, in addition to natural overwintering, a greenhouse can also be used for overwintering to shorten the market time of commercial spiny eels.

[0070] Example 3

[0071] In the cultivation method of hybrid spiny eels, the hybrid combinations of female big spiny eels and male Chinese spiny eels (big spiny eel♀×Chinese spiny eel♂) in Example 1 or male big spiny eels and female Chinese spiny eels (big spiny eel♂×Chinese spiny eel♀) in Example 2 can be used; as a control, Control Example 1 uses a self-cross combination: female big spiny eels and male big spiny eels (big spiny eel♀×big spiny eel♂), and Control Example 2 uses a self-cross combination: female Chinese spiny eels and male Chinese spiny eels (Chinese spiny eel♀×Chinese spiny eel♂). The artificial reproduction fertilization rate, hatching rate, and survival rate of different combinations are shown in Table 1.

[0072] Table 1 Fertilization rate, hatching rate, and survival rate of big spiny eels and Chinese spiny eels in different combinations

[0073] Combination Fertilization rate (%) Hatching rate (%) Survival rate (%) Example 1 Macrognathus aculeatus♀×Sinobdella sinensis♂ 91.2 82.7 67.8 Example 2 Macrognathus aculeatus♂×Sinobdella sinensis♀ 90.3 81.5 66.5 Control Example 1 Macrognathus aculeatus♀×Macrognathus aculeatus♂ 59.3 51.6 62.7 Control Example 2 Sinobdella sinensis♀×Sinobdella sinensis♂ 62.7 58.2 63.4

[0074] Example 4

[0075] In this example, the overwintering survival rate of spiny eels bred from the above 4 combinations was studied. 100 fry from each of the 4 combinations of big spiny eel♀×Chinese spiny eel♂, big spiny eel♂×Chinese spiny eel♀, big spiny eel♀×big spiny eel♂, and Chinese spiny eel♀×Chinese spiny eel♂ were taken and put into the test pool. The test pool is separated from the pond and has no temperature control device. It is a cement pool with a bottom area of 2m * 10m, a water depth of 50 cm, and the side walls are fully covered with smooth ceramic tiles. It is equipped with an aeration device, and the dissolved oxygen content is not less than 5 mg / L for 24 hours. Fish nests or PVC pipes are laid at the bottom of the test pool as shelters for broodstock.

[0076] Test time: From November 10, 2021 to April 10, 2022, overwintering naturally.

[0077] Test location: Shalan Village, Sanjiao Town, Zhongshan City, Guangdong Province.

[0078] The test results are shown in Table 2.

[0079] Table 2 Overwintering survival rate of Mastacembelus armatus and Spinibarbus sinensis in different combinations

[0080] Combination Survival rate (%) Example 1 Macrognathus aculeatus♀×Sinobdella sinensis♂ 48.2 Example 2 Macrognathus aculeatus♂×Sinobdella sinensis♀ 46.3 Control Example 1 Macrognathus aculeatus♀×Macrognathus aculeatus♂ 10.9 Control Example 2 Sinobdella sinensis♀×Sinobdella sinensis♂ 43.2

[0081] At low temperature, the physiological activity of Mastacembelus armatus decreases, resulting in a decline in its immunity and making it vulnerable to the invasion of external pathogens. Moreover, Mastacembelus armatus is not cold-tolerant. Therefore, the survival rate of the self-bred offspring of Mastacembelus armatus in Comparative Example 1 is relatively low.

[0082] Spinibarbus sinensis has a higher latitude of its growth environment and better cold tolerance than Mastacembelus armatus. The results show that the survival rate of the hybrid offspring of Mastacembelus armatus and Spinibarbus sinensis in Example 1 and Example 2 is slightly higher than that of the self-bred offspring of Spinibarbus sinensis after natural overwintering. It shows that the spiny eels cultivated by the hybridization method of Mastacembelus armatus and Spinibarbus sinensis can improve the poor cold tolerance and population degradation problems of Mastacembelus armatus itself.

[0083] The above content is only an example and explanation of the structure of the present invention. Its description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these obvious replacement forms all belong to the protection scope of the present invention.

Claims

1. A cultivation method of hybrid spiny eels, characterized in that, It includes the following steps: S1. Selection of broodstock: Select Sinobdella sinensis and Mastacembelus armatus as broodstock for reproduction. The weight of the selected broodstock is 20 - 30% greater than the median weight of the same batch and the same sex. S2. Inducing spawning and fertilization: Transfer the selected broodstock to the spawning pond, maintain the water temperature at 28 - 30 °C to make the broodstock reach the best pre-spawning physiological state; after injecting the spawning-inducing drugs, collect eggs and semen respectively; pour the diluted semen into the container containing eggs, and fully mix the semen and eggs to complete fertilization. S3. Larval cultivation: After the larvae hatch, feed the initial feed when the yolk sac is completely absorbed, and feed three times a day; gradually add commercial feed as the larvae grow. S4. Cultivation of marketable fish: When the larvae grow to 4 - 5 cm, transfer them to the pond for cultivation. Feed twice a day according to the "three-fixed" principle. In the step S1, the selection of Sinobdella sinensis and Mastacembelus armatus as broodstock for reproduction specifically includes: Select male Sinobdella sinensis and female Mastacembelus armatus as broodstock for reproduction. Among them, the male Sinobdella sinensis has bright body patterns, a slender body shape, a relatively hard abdomen, and its weight is greater than 18 g. The female Mastacembelus armatus has a yellowish-brown body color, a thick and short body shape, a swollen and soft abdomen with good elasticity when touched, and its weight is greater than 160 g. Or in the step S1, the selection of Sinobdella sinensis and Mastacembelus armatus as broodstock for reproduction specifically includes: Select female Sinobdella sinensis and male Mastacembelus armatus as broodstock for reproduction. Among them, the weight of the female Sinobdella sinensis is greater than 16 g, and the weight of the male Mastacembelus armatus is greater than 220 g. In the step S2, the spawning-inducing drugs include human chorionic gonadotropin HCG, luteinizing hormone-releasing hormone LRH-A2, and domperidone DOM. Before injection, they are mixed evenly according to the following dosage ratios: HCG 800 - 1200 IU / kg, LRH-A2 8 - 12 μg / kg, DOM 4 - 6 mg / kg. Take the mixed spawning-inducing drugs, dilute them 10 times with sterile injection saline, inject 10 mL / kg for each female broodstock each time, and give the second injection 12 hours after the first injection, with the second dose halved. Or, take the mixed spawning-inducing drugs without dilution, inject the male broodstock only once, at the same time as the second injection of the female broodstock, and the injection dose is 0.5 mL / kg. After injection, put the broodstock back into the spawning pond and wait for the spawning-inducing drugs to take effect. The fertilization in S2 is wet fertilization. Before collecting eggs and semen, it is necessary to anesthetize the broodstock with the fish anesthetic MS-222. Egg collection: Wrap the body of the anesthetized female broodstock with a wet towel, lie on the side with the cloaca facing one side, slowly massage and squeeze the abdomen from front to back to make the eggs flow out into a pre-prepared clean container. After squeezing the eggs, put the female broodstock into clean water for aeration to make it wake up from the anesthetized state. Semen collection: Wrap the body of the anesthetized male broodstock with a wet towel, lie on the side to make the cloaca close to the pre-prepared container, slowly squeeze the abdomen to make the semen flow into the container. After collecting the semen, add sterilized saline and mix well; put the male broodstock into clean water for aeration to make it wake up from the anesthetized state. Fish egg fertilization: Slowly pour the diluted semen into the container with eggs, and pour the two containers back and forth to fully mix the semen and eggs to complete fertilization; After the fish eggs are fertilized, they are hatched. The temperature of the hatching environment is not lower than 27 °C, and the dissolved oxygen is not lower than 5 mg / L.

2. The cultivation method of the hybrid spiny loach according to claim 1, characterized in that In the step S1, the broodstock should be selected before the breeding period in March and April every year. Both male and female broodstock should have a uniform and regular body shape, no body surface deformities, no injuries or diseases, and normal feeding; for male broodstock, select individuals with semen overflowing when the abdomen is squeezed; for female broodstock, select individuals with a swollen abdomen and well-developed gonads, and raise the selected broodstock in the temporary rearing pond.

3. The cultivation method of the hybrid spiny eel according to claim 1, characterized in that, In the S3 larval rearing, the starting feed is cooked egg yolk or rotifers, and they are fed three times a day at 6:00, 14:00, and 22:00; in the middle stage, invertebrate bait is added, and in the later stage, commercial feed is gradually added and replaced.

4. The cultivation method of the hybrid spiny eel according to claim 1, characterized in that, In the S4 commercial fish farming, the larvae are stocked in the pond at a stocking density of 4000 - 4500 tails per mu, and sufficient fish nests or PVC pipes should be arranged in advance in the pond as shelters; they are fed twice a day with Macrognathus aculeatus commercial feed at 7:00 and 18:

00.

5. The cultivation method of the hybrid spiny loach according to claim 2, characterized in that, The construction specifications of the temporary rearing pond are a 2 * 10 m cement pond with a water depth of 50 cm, and the bottom and walls of the pond should be covered with smooth tiles. PVC pipes or fish nests are arranged at the bottom of the pond for breeding broodstock to hide, and the oxygen content in the water is not lower than 5 mg / L; during the feeding process of the broodstock in the temporary rearing pond, they are fed twice a day at 7:00 and 18:00 with Macrognathus aculeatus commercial feed added with 20% fresh fish and shrimp mince.