Large-scale artificial propagation method for percocypris pingi and application

Abstract

The invention provides a large-scale artificial propagation method for percocypris pingi and application, and belongs to the technical field of artificial propagation in aquaculture. The invention provides a large-scale artificial propagation method for percocypris pingi. The large-scale artificial propagation method comprises the following steps: 1) selecting male and female parent percocypris pingi in a propagation period; (2) anesthetizing the parent percocypris pingi with an anesthetic, and injecting oxytocin after anesthesia; according to the method, the spawning induction effect can be effectively improved, the mortality rate of parent fishes can be reduced, and reference can be provided for batch production of the percocypris pingi fry.

Description

Technical Field

[0001] This invention relates to the field of artificial breeding technology in aquaculture, and in particular to a method and application for large-scale artificial breeding of the back-backed carp. Background Technology

[0002] Back-back perch ( Percocypris pingi retrodorslis (Cui et Chu, 1990) Belongs to the family Cyprinidae, subfamily Barbinae, and genus *Cyprinus*. It is endemic to parts of the Lancang and Nujiang Rivers and their tributaries, and is locally known as Jianghua or Huayu. *Cyprinus* has a long head, laterally compressed body, subsuperior mouth, two pairs of well-developed barbels (the corner barbels are slightly longer than the snout barbels), a raised back behind the head, and a slightly arched dorsal and ventral margin. The scales on the chest, abdomen, and back are small and embedded under the skin, with no exposed areas. The body surface is covered with black spots, the lateral line is complete, the dorsal fin has an unbranched terminal root, and the posterior margin is serrated. Common wild individuals weigh 1 kg to 4 kg. It lives in the upper and middle layers of the water, is a predatory fish, and feeds on small fish and zooplankton. The breeding season is from late January to late March, with an optimal breeding water temperature of 14℃ to 17℃. *Cyprinus* has tender flesh, few intramuscular bones, and a delicious flavor. Its body color and markings also make it valuable for both consumption and ornamental purposes.

[0003] Due to factors such as habitat changes and invasive species, the wild populations are threatened in some areas, and the amount of wild resources has decreased significantly. They have been listed as Class II in the "List of National Key Protected Wild Animals in China".

[0004] Large-scale artificial breeding of the Chinese sturgeon and subsequent release into specific waters is an effective method for population recovery. Currently, artificial breeding techniques for the Chinese sturgeon face the following challenges: 1. Improper use of feed during broodstock rearing can lead to poor or absent gonadal development in broodstock. 2. The dosage and timing of the anesthetic before spawning in parent fish cannot be accurately controlled, which may lead to violent struggles during injection, causing injury and infection in the parent fish, or making it difficult for them to wake up, affecting their normal physiological functions and causing later infections. 3. Inaccurate control of the dosage of spawning stimulants for broodstock leads to low spawning rates or an inability to accurately control the spawning time.

[0005] Therefore, it is urgent to establish a scientific and standardized artificial breeding technology system for large-scale back-back carp in order to solve key technical problems such as poor gonadal development of parent fish, low spawning rate and poor hatching stability. Summary of the Invention

[0006] The purpose of this invention is to provide a method for large-scale artificial breeding of *Carassius simonii*, which effectively improves the spawning effect and fertilization rate, and reduces the mortality rate of parent fish.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for large-scale artificial breeding of the back-back carp, comprising the following steps: 1) Select male and female parent carp that are in their breeding season; 2) The parent carp was anesthetized with an anesthetic, and oxytocin was injected after anesthesia; 3) Artificial insemination and artificial incubation of the induced-spawning sea bass; 4) Cultivate the hatched fish fry; The oxytocins are LRH-A-(2), DOM and HCG.

[0008] Preferably, in step 1), the female carp with a swollen and soft abdomen has a clear outline of ovaries, and the genital opening is swollen, slightly red, and protruding. When the male carp is gently pressed on the abdomen, milky white semen that disperses upon contact with water flows out.

[0009] Preferably, the anesthetic agent mentioned in step 2) is Fisherman's Treasure, whose main component is MS-222, and the dosage is 45~55 mL / m 3 The anesthesia time is 2-4 minutes.

[0010] Preferably, in step 2), the oxytocin injection is performed on the female fish in two separate injections. The first injection dose is LRH-A-(2) 10~15 μg / kg, DOM 2~5 mg / kg and HCG 800~1200 IU / kg. The second injection uses the same type and dose of oxytocin as the first injection, with a 24-hour interval between the two injections. The male fish is injected once, with a dose that is half of the total dose of the female fish. The injection time is synchronized with the second injection time of the female fish.

[0011] Preferably, in step 3), artificial insemination involves squeezing the female fish's eggs and the male fish's semen into a dry container, mixing them with a dry feather, and after full fertilization, rinsing with clean water 3-4 times to remove any remaining semen.

[0012] Preferably, in step 3), the artificial incubation involves incubating the fertilized eggs using a round-bottom incubator, controlling the dissolved oxygen concentration in the water to be ≥6.5 mg / L, the water temperature to be 15.5~16 ℃, the pH to be 6.5~7.7, and the incubation time to be 5~6 days.

[0013] Preferably, the number of fertilized eggs in the round-bottom incubator is 25,000 to 30,000.

[0014] Preferably, the cultivation in step 4) is as follows: after the fry hatch, brine shrimp or shredded tubifex worms are used as the first food. After 20-25 days of acclimation, artificial compound feed is used. After complete acclimation, the fry are transferred to the rearing pond and fed with cladoceran animal feed.

[0015] The present invention also provides an application of the method in the breeding of back sea bass.

[0016] The large-scale artificial breeding method provided by this invention significantly improves the success rate of induced spawning by strictly selecting mature male and female fish as broodstock and controlling the dosage and injection method of oxytocin. Artificial insemination is conducted in a cool environment to ensure the egg container is dry and improve fertilization rate. Strict control of incubation water quality and prevention of fertilized egg accumulation, along with maintaining smooth water flow, effectively reduces mortality during incubation. Strict control of the anesthesia and oxytocin injection time minimizes stress damage, and erythromycin ointment is used to treat wounds after induced spawning to effectively prevent infection and promote healing. This artificial breeding method effectively improves induced spawning results and reduces broodstock mortality, providing a reference for the mass production of juvenile carp. Attached Figure Description

[0017] Figure 1 This is a flowchart of the large-scale artificial breeding process of the back-back perch in Example 1; Figure 2 This is a schematic diagram of incubation in an incubator in Example 1. Detailed Implementation

[0018] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0019] Example 1

[0020] 1. Broodstock breeding

[0021] Select well-developed and healthy *Carp spp.* as broodstock, disinfect them, and then place them in a square broodstock pond with an area of ​​≥50 m² for rearing. 2 The water depth is 1.0 m, dissolved oxygen is ≥6.8 mg / L, and the annual water temperature in the culture pond is between 10~17 ℃. Gravity flow is used for cultivation, and the inflow rate of the culture pond is 9 m³ / s. 3 / h, the breeding density is 100 fish / pond, the female-to-male ratio is 1:1, and they are fed with carp compound feed with a protein content of 35%. The daily feeding amount is 3% of the body weight of the parent fish, and they are fed twice a day, in the morning and evening. Every other day, they are fed live bait fish such as carp (5~10 cm), loach, and river shrimp.

[0022] 2. Selection of parent fish

[0023] Sexing: During the breeding season, spawning can be induced when the water temperature is around 14 ℃. On February 13, 2022, select healthy, disease-free, and uninjured parent fish. There are 5 female fish, weighing about 5 kg, with a swollen and soft abdomen, a clear outline of the ovary, and a swollen, slightly reddish and protruding genital opening. There are 3 male fish, weighing about 1.8 kg. When the abdomen is gently pressed, semen will flow out. It is milky white and disperses upon contact with water.

[0024] 3. Anesthesia of broodstock

[0025] Anesthesia was performed using Fisherman's Treasure (main ingredient MS-222). The anesthetic was poured into water and stirred thoroughly before the parent fish were placed in the water for anesthesia. The dosage was 50 mL / m3, and the anesthesia time was 3 min.

[0026] 4. Labor-inducing drugs

[0027] Using sterile pure water instead of injectable saline to prepare the oxytocin effectively avoids crystallization. The oxytocin drugs are: LRH-A-(2), DOM, and HCG.

[0028] The female fish were injected for the first time with LRH-A-(2) 12.5 μg / kg, DOM 3.5 mg / kg, and HCG 1000 IU / kg; the second injection was the same type and dosage of oxytocin as the first, with an interval of 24 hours.

[0029] The male fish is given a single injection, with the dosage being half of the total dosage for the female fish, and the injection time is synchronized with the second injection time for the female fish.

[0030] Administer the oxytocin injection to both female and male carp according to the above dosage. After injection, apply erythromycin ointment to the wound to effectively prevent leakage and infection. Separate the injected females and males into different ponds to avoid chasing and affecting the duration of the oxytocin effect.

[0031] Oxytocin was administered followed by oxygen therapy for resuscitation.

[0032] 5. Artificial insemination

[0033] The effect time was 54 hours from the first injection. First, the female carp broodstock, ready to spawn, were removed from the water supply. Their bodies and genital openings were dried with a towel. The eggs were squeezed into a dry container. The same procedure was performed, squeezing the sperm of the male broodstock onto the eggs. The sperm and eggs were mixed together with a dry feather to ensure thorough fertilization. After fertilization, the eggs were rinsed 3-4 times with clean water at a temperature of 14.2℃ to remove any remaining sperm. The fertilized eggs were counted in a measuring cup, yielding 151,000 eggs, achieving a 100% spawning rate.

[0034] 6. Hatching of fertilized eggs

[0035] Fertilized eggs after dry insemination are incubated in an acrylic transparent round-bottom incubator (e.g.) Figure 2As shown in the image, the inner wall is smooth and does not damage the eggs. Each hatching cylinder holds approximately 28,000 fertilized eggs. Air intake at the bottom allows the fertilized eggs to suspend in the hatching water, preventing them from piling up. The circulating water is filtered and sterilized, ensuring a dissolved oxygen concentration of ≥6.5 mg / L. The water temperature during hatching is controlled at around 15.5 ℃, and the pH is 7.0. After 5-6 days, the fertilized eggs begin to hatch, resulting in 89,000 hatched fry with a fertilization rate of 79.47%.

[0036] 7. Seedling cultivation

[0037] Seedling rearing: When the hatched fry begin to swim horizontally, use brine shrimp or chopped tubifex worms as their first food. After 25 days of feeding, the fry are acclimated to artificial feed. Once the fry are fully acclimated, they are transferred to a seedling rearing pond and fed cladoceran animal feed every other day.

[0038] Example 2

[0039] 1. Broodstock breeding

[0040] Select well-developed and healthy *Carp spp.* as broodstock, disinfect them, and then place them in a square broodstock pond with an area of ​​≥50 m² for rearing. 2 The water depth is 1.0 m, dissolved oxygen is ≥6.8 mg / L, and the annual water temperature in the culture pond is between 10~17 ℃. Gravity flow is used for cultivation, and the inflow rate of the culture pond is 9 m³ / s. 3 / h, the breeding density is 100 fish / pond, the female-to-male ratio is 1:1, and they are fed with carp compound feed with a protein content of 35%. The daily feeding amount is 3% of the body weight of the parent fish, and they are fed twice a day, in the morning and evening. Every other day, they are fed live bait fish such as carp (5~10 cm), loach, and river shrimp.

[0041] 2. Selection of parent fish

[0042] Sexing: During the breeding season, spawning can be induced when the water temperature is around 14 ℃. On February 10, 2023, select healthy, disease-free, and uninjured parent fish. There are 3 female fish, weighing about 6 kg, with a swollen and soft abdomen, a clear outline of the ovary, and a swollen, slightly reddish and protruding genital opening. There are 3 male fish, weighing about 1.8 kg. When the abdomen is gently pressed, semen will flow out. It is milky white and disperses upon contact with water.

[0043] 3. Anesthesia of broodstock

[0044] Anesthesia was performed using Fisherman's Treasure (main ingredient MS-222). The anesthetic was poured into water and stirred thoroughly before the parent fish were placed in the water for anesthesia. The dosage was 50 mL / m3, and the anesthesia time was 3 min.

[0045] 4. Labor-inducing drugs

[0046] Using sterile pure water instead of injectable saline to prepare the oxytocin effectively avoids crystallization. The oxytocin drugs are: LRH-A-(2), DOM, and HCG.

[0047] The female fish were injected for the first time with LRH-A-(2) 12.5 μg / kg, DOM 3.5 mg / kg, and HCG 1000 IU / kg; the second injection was the same type and dosage of oxytocin as the first, with an interval of 24 h.

[0048] The male fish is given a single injection, with the dosage being half of the total dosage for the female fish, and the injection time is synchronized with the second injection time for the female fish.

[0049] Administer the oxytocin injection to both female and male carp according to the above dosage. After injection, apply erythromycin ointment to the wound to effectively prevent leakage and infection. Separate the injected females and males into different ponds to avoid chasing and affecting the duration of the oxytocin effect.

[0050] Oxytocin was administered followed by oxygen therapy for resuscitation.

[0051] 5. Artificial insemination

[0052] The effect time was 48 hours from the first injection. First, the female carp broodstock, ready to spawn, were removed from the water supply. Their bodies and genital openings were dried with a towel. The eggs were squeezed into a dry container. The same procedure was performed, squeezing the sperm of the male broodstock onto the eggs. The sperm and eggs were mixed thoroughly with a dry feather. After fertilization, the eggs were rinsed 3-4 times with clean water at 14.1℃ to remove any remaining sperm. The fertilized eggs were then counted in a measuring cup, yielding 90,000 eggs, achieving a 100% spawning rate.

[0053] 6. Hatching of fertilized eggs

[0054] Fertilized eggs after dry insemination are incubated in an acrylic transparent round-bottom incubator (e.g.) Figure 1 As shown in the image, the inner wall is smooth and does not damage the eggs. Each hatching cylinder holds approximately 28,000 fertilized eggs. Air intake at the bottom allows the fertilized eggs to suspend in the hatching water, preventing them from piling up. The circulating water is filtered and sterilized, ensuring a dissolved oxygen concentration of ≥6.5 mg / L in the hatching water. The water temperature is controlled at around 15.5℃ and the pH is 6.5 during the hatching process. After 5-6 days, the fertilized eggs begin to hatch, resulting in 36,000 hatched fry with a fertilization rate of 66.67%.

[0055] 7. Seedling cultivation

[0056] Seedling rearing: When the hatched fry begin to swim horizontally, use brine shrimp or chopped tubifex worms as their first food. After 25 days of feeding, the fry are acclimated to artificial feed. Once the fry are fully acclimated, they are transferred to a seedling rearing pond and fed cladoceran animal feed every other day.

[0057] Example 3

[0058] 1. Broodstock breeding

[0059] Select well-developed and healthy *Carp spp.* as broodstock, disinfect them, and then place them in a square broodstock pond with an area of ​​≥50 m² for rearing. 2 The water depth is 1.0 m, dissolved oxygen is ≥6.8 mg / L, and the annual water temperature in the culture pond is between 10~17 ℃. Gravity flow is used for cultivation, and the inflow rate of the culture pond is 9 m³ / s. 3 / h, the breeding density is 100 fish / pond, the female-to-male ratio is 1:1, and they are fed with carp compound feed with a protein content of 35%. The daily feeding amount is 3% of the body weight of the parent fish, and they are fed twice a day, in the morning and evening. Every other day, they are fed live bait fish such as carp (5~10 cm), loach, and river shrimp.

[0060] 2. Selection of parent fish

[0061] Sexing: During the breeding season, spawning can be induced when the water temperature is around 14 ℃. On February 16, 2024, select healthy, disease-free, and uninjured parent fish. There are 15 female fish, weighing about 5.8 kg, with a swollen and soft abdomen, a clear outline of the ovaries, and a swollen, slightly reddish, and protruding genital opening. There are 6 male fish, weighing about 2 kg. When the abdomen is gently pressed, semen will flow out. It is milky white and disperses upon contact with water.

[0062] 3. Anesthesia of broodstock

[0063] Anesthesia was performed using Fisherman's Treasure (main ingredient MS-222). The anesthetic was poured into water and stirred thoroughly before the parent fish were placed in the water for anesthesia. The dosage was 50 mL / m3, and the anesthesia time was 3 min.

[0064] 4. Labor-inducing drugs

[0065] Using sterile pure water instead of injectable saline to prepare the oxytocin effectively avoids crystallization. The oxytocin drugs are: LRH-A-(2), DOM, and HCG.

[0066] The female fish were injected for the first time with LRH-A-(2) 12.5 μg / kg, DOM 3.5 mg / kg, and HCG 1000 IU / kg; the second injection was the same type and dosage of oxytocin as the first, with an interval of 24 h.

[0067] The male fish is given a single injection, with the dosage being half of the total dosage for the female fish, and the injection time is synchronized with the second injection time for the female fish.

[0068] Administer the oxytocin injection to both female and male carp according to the above dosage. After injection, apply erythromycin ointment to the wound to effectively prevent leakage and infection. Separate the injected females and males into different ponds to avoid chasing and affecting the duration of the oxytocin effect.

[0069] Oxytocin was administered followed by oxygen therapy for resuscitation.

[0070] 5. Artificial insemination

[0071] The effect time was 60 hours from the first injection. First, the female carp broodstock, ready to spawn, were removed from the water supply. Their bodies and genital openings were dried with a towel. The eggs were squeezed into a dry container. The same procedure was performed, squeezing the sperm of the male broodstock onto the eggs. The sperm and eggs were mixed together with a dry feather to ensure thorough fertilization. After fertilization, the eggs were rinsed 3-4 times with clean water at 14.4℃ to remove any remaining sperm. The fertilized eggs were then rinsed 3 times with clean water to remove any remaining semen. The eggs were counted in a measuring cup, yielding 500,000 eggs, achieving a 100% spawning rate.

[0072] 6. Hatching of fertilized eggs

[0073] Fertilized eggs after dry insemination are incubated in an acrylic transparent round-bottom incubator (e.g.) Figure 1 As shown in the image, the inner wall is smooth and does not damage the eggs. Each hatching cylinder holds approximately 28,000 fertilized eggs. Air intake at the bottom allows the fertilized eggs to suspend in the hatching water, preventing them from piling up. The circulating water is filtered and sterilized, ensuring a dissolved oxygen concentration of ≥6.5 mg / L. The water temperature during hatching is controlled at around 15.5 ℃, and the pH is 7.7. After 5-6 days, the fertilized eggs begin to hatch, resulting in 398,000 hatched fry with a fertilization rate of 90.6%.

[0074] 7. Seedling cultivation

[0075] Seedling rearing: When the hatched fry begin to swim horizontally, use brine shrimp or chopped tubifex worms as their first food. After 25 days of feeding, the fry are acclimated to artificial feed. Once the fry are fully acclimated, they are transferred to a seedling rearing pond and fed cladoceran animal feed every other day.

[0076] Example 4

[0077] 1. Broodstock breeding

[0078] Select well-developed and healthy *Carp spp.* as broodstock, disinfect them, and then place them in a square broodstock pond with an area of ​​≥50 m² for rearing. 2 The water depth is 1.0 m, dissolved oxygen is ≥6.8 mg / L, and the annual water temperature in the culture pond is between 10~17 ℃. Gravity flow is used for cultivation, and the inflow rate of the culture pond is 9 m³ / s. 3 / h, the breeding density is 100 fish / pond, the female-to-male ratio is 1:1, and they are fed with carp compound feed with a protein content of 35%. The daily feeding amount is 3% of the body weight of the parent fish, and they are fed twice a day, in the morning and evening. Every other day, they are fed live bait fish such as carp (5~10 cm), loach, and river shrimp.

[0079] 2. Selection of parent fish

[0080] Sexing: During the breeding season, spawning can be induced when the water temperature is around 14 ℃. On February 7, 2025, select healthy, disease-free, and uninjured parent fish. There are 5 female fish, weighing about 6 kg, with a swollen and soft abdomen, a clear outline of the ovary, and a swollen, slightly reddish and protruding genital opening. There are 3 male fish, weighing about 2 kg. When the abdomen is gently pressed, semen will flow out. It is milky white and disperses upon contact with water.

[0081] 3. Anesthesia of broodstock

[0082] Anesthesia was performed using Fisherman's Treasure (main ingredient MS-222). The anesthetic was poured into water and stirred thoroughly before the parent fish were placed in the water for anesthesia. The dosage was 50 mL / m3, and the anesthesia time was 3 min.

[0083] 4. Labor-inducing drugs

[0084] Using sterile pure water instead of injectable saline to prepare the oxytocin effectively avoids crystallization. The oxytocin drugs are: LRH-A-(2), DOM, and HCG.

[0085] The female fish were injected for the first time with LRH-A-(2) 12.5 μg / kg, DOM 3.5 mg / kg, and HCG 1000 IU / kg; the second injection was the same type and dosage of oxytocin as the first, with an interval of 24 hours.

[0086] The male fish is given a single injection, with the dosage being half of the total dosage for the female fish, and the injection time is synchronized with the second injection time for the female fish.

[0087] Administer the oxytocin injection to both female and male carp according to the above dosage. After injection, apply erythromycin ointment to the wound to effectively prevent leakage and infection. Separate the injected females and males into different ponds to avoid chasing and affecting the duration of the oxytocin effect.

[0088] Oxytocin was administered followed by oxygen therapy for resuscitation.

[0089] 5. Artificial insemination

[0090] The effect time was 54 hours from the first injection. The female carp broodstock, ready to spawn, were first removed from the water supply. Their bodies and genital openings were dried with a towel. The eggs were squeezed into a dry container. The same procedure was performed, squeezing the sperm of the male broodstock onto the eggs. The sperm and eggs were mixed together with a dry feather to ensure thorough fertilization. After fertilization, the eggs were rinsed 3-4 times with clean water at 13.9°C to remove any remaining sperm. The fertilized eggs were then counted in a measuring cup, yielding 365,000 eggs, achieving a 100% spawning rate.

[0091] 6. Hatching of fertilized eggs

[0092] Fertilized eggs after dry insemination are incubated in an acrylic transparent round-bottom incubator (e.g.) Figure 1 As shown in the image, the inner wall is smooth and does not damage the eggs. Each hatching cylinder holds approximately 28,000 fertilized eggs. Air intake at the bottom allows the fertilized eggs to suspend in the hatching water, preventing them from piling up. The circulating water is filtered and sterilized, ensuring a dissolved oxygen concentration of ≥6.5 mg / L in the hatching water. The water temperature is controlled at around 15.5 ℃ and the pH is 7.0 during the hatching process. After 5-6 days, the fertilized eggs begin to hatch, resulting in 256,000 hatched fry, with a fertilization rate of 83.6%.

[0093] 7. Seedling cultivation

[0094] Seedling rearing: When the hatched fry begin to swim horizontally, use brine shrimp or chopped tubifex worms as their first food. After 25 days of feeding, the fry are acclimated to artificial feed. Once the fry are fully acclimated, they are transferred to a seedling rearing pond for further rearing, and fed cladoceran animal feed every other day.

[0095] The artificial propagation effects of each embodiment were statistically analyzed, and the results are shown in Table 1.

[0096] Table 1. Statistics on the effects of artificial breeding in Examples 1-4

[0097] As can be seen, the spawning rate of the parent fish in all four embodiments of this application can reach 100%, the fertilization rate of embodiments 3 and 4 both reach more than 80%, and no parent fish die.

[0098] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for large-scale artificial breeding of *Carassius simonii*, characterized in that, Includes the following steps: 1) Select male and female parent carp that are in their breeding season; 2) The parent carp was anesthetized with an anesthetic, and oxytocin was injected after anesthesia; 3) Artificial insemination and artificial incubation of the induced spawning carp; 4) Cultivate the hatched fish fry; The oxytocins are LRH-A-(2), DOM and HCG.

2. The method as described in claim 1, characterized in that, Step 1) The female carp with a swollen and soft abdomen has a clear outline of ovaries, and the genital opening is swollen, slightly red, and protruding. When the male carp is gently pressed on the abdomen, milky white semen that disperses upon contact with water flows out.

3. The method as described in claim 1, characterized in that, Step 1) The anesthetic agent mentioned is Fisherman's Treasure, the main component of which is MS-222, and the dosage is 45~55 mL / m 3 The anesthesia time is 2-4 minutes.

4. The method as described in claim 1, characterized in that, Step 2) The oxytocin injection is given to the female fish in two injections. The first injection dose is LRH-A-(2) 10~15 μg / kg, DOM 2~5 mg / kg and HCG 800~1200 IU / kg. The second injection is the same type and dose of oxytocin as the first injection. The two injections are 24 hours apart. The male fish is injected once, with a dose of 1 / 2 of the total dose of the female fish. The injection time is synchronized with the second injection time of the female fish.

5. The method as described in claim 1, characterized in that, Step 3) Artificial insemination involves squeezing the female fish's eggs and the male fish's semen into a dry container, mixing them with a dry feather, and rinsing with clean water 3-4 times after fertilization to remove any residual semen.

6. The method as described in claim 1, characterized in that, Step 3) The artificial incubation involves incubating the fertilized eggs in a round-bottom incubator. During the incubation process, the dissolved oxygen concentration in the water is controlled to be ≥6.5 mg / L, the water temperature is 15.5~16 ℃, the pH is 6.5~7.7, and the incubation time is 5~6 days.

7. The method as described in claim 6, characterized in that, The number of fertilized eggs in the round-bottomed incubator is 25,000 to 30,000.

8. The method as described in claim 1, characterized in that, Step 4) The cultivation process is as follows: after the fry hatch, brine shrimp or shredded tubifex worms are used as the first food. After 20-25 days of acclimation, artificial feed is used. After complete acclimation, the fry are transferred to a rearing pond and fed with cladoceran animal feed.

9. The application of the method according to any one of claims 1 to 8 in the breeding of back bass.

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