Anti-season artificial propagation method for crucian carp

Abstract

The invention discloses an out-of-season artificial propagation technical method for crucian carp. The technical method specifically comprises the key steps of water temperature and illumination control of an intelligent culture system, parent fish screening and concentrated intensified culture, parent fish ripening acceleration, artificial spawning induction, artificial insemination, incubation and the like. Aiming at seasonal limitation of natural breeding of the crucian carp, by scientifically regulating and controlling an illumination period and a water temperature environment and accurately simulating ecological conditions suitable for breeding of the crucian carp, it is ensured that parent fishes of the crucian carp can synchronously reach physiological states of periodic normal ovulation and spermiation in an unnatural spawning season from October to January of the next year; the activity and quality of germ cells can be obviously improved; meanwhile, an innovative breeding mode and an exclusive feeding scheme are combined, the industrial pain points that eggs of female crucian carp of ice cream are prone to aging and parent fishes only spawn once a year in a natural state are effectively overcome, and anti-season stable breeding is achieved.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, specifically relating to a method for off-season artificial breeding of Qihe crucian carp. Background Technology

[0002] Qihe crucian carp ( Carassius auratus in Qihe The Qihe River crucian carp, commonly known as the "double-backed crucian carp," is a superior local breed developed through long-term ecological adaptation in the Qihe River basin. As a precious fish species unique to Henan Province, it is not only listed as a key protected species in the "Henan Province Wildlife Protection List," but also bears the ancient record of "slender bamboo poles, used for fishing in the Qihe River" in the Book of Songs, carrying profound cultural heritage and ecological value. Compared to ordinary crucian carp, the Qihe River crucian carp is a naturally occurring double triploid, possessing excellent characteristics such as rapid growth, a broad and thick back, and strong environmental tolerance. Its meat content reaches 73%, protein content is 19.11%, and total amino acid content exceeds 18%. With its tender flesh and unique flavor, it ranks among the "Three Treasures of the Qihe River" and boasts significant market value.

[0003] However, the development of this highly promising specialty fish industry is mired in bottlenecks, a stark contrast to its renowned reputation. According to data from the first provincial aquaculture germplasm resource survey, in 2021, Henan Province had only 8 Qihe crucian carp farming entities, with a total farming area of ​​1014 mu (approximately 67 hectares) and a total output of 387 tons, accounting for only 0.7% of the province's total crucian carp production and virtually negligible compared to the national output of 2.84 million tons. In contrast, the equally renowned Pengze crucian carp has a farming area exceeding 60,000 hectares, an output exceeding 600,000 tons, accounting for approximately 21% of the national crucian carp production, and exports reaching 80,000 tons, reaching overseas markets. The difference in industry scale between the two is enormous. The root cause lies in the increasingly prominent problem of germplasm degradation. Long-term inbreeding has led to slow growth and decreased disease resistance in Qihe crucian carp, hindering the improvement of farming efficiency. Most importantly, the natural reproduction of Qihe crucian carp is concentrated from April to June, and traditional artificial breeding techniques are also limited to this spring natural breeding cycle, lacking support for off-season breeding techniques. This technological limitation restricts the year-round supply of fertilized eggs and fry of the Qihe crucian carp, resulting in a significant seasonal shortage of fry. Furthermore, the time constraint on obtaining fertilized eggs hinders the application of advanced breeding techniques such as gene editing and whole-genome selection, further limiting germplasm innovation and basic research. Ultimately, this has made it difficult for the Qihe crucian carp industry to break free from its fragmented and small-scale development status.

[0004] From the perspective of industry development trends, my country's fisheries are facing a critical juncture of transformation and upgrading. The "2024 China Fisheries Statistical Yearbook" shows that the national freshwater fish production reached 27.716 million tons, with crucian carp ranking fifth. However, traditional crucian carp farming is mostly concentrated in freshwater ponds in the central, eastern, and southern regions, leaving very limited room for further expansion of farming area and production. At the same time, my country has approximately 1.49 billion mu (166 million hectares) of saline-alkali land, of which 690 million mu (46 million hectares) are low-lying saline-alkali water resources. More than 90% of these areas have long been abandoned, and native fish species in saline-alkali waters have low fishery value, making development and utilization difficult. As a salt-tolerant major freshwater fish, the Qihe crucian carp's variety improvement and aquaculture technology innovation have become a crucial breakthrough in overcoming the limited development space of my country's fisheries and promoting the development of saline-alkali land resources.

[0005] At the technical level, although domestic research institutions have conducted systematic research on the biological characteristics, artificial breeding, pond culture, and resource protection of Qihe crucian carp since the 1980s, the industry's development is still constrained by many technical bottlenecks: traditional breeding methods are time-consuming and inefficient, and the creation of new varieties is slow; artificial breeding technology focuses on conventional breeding in spring, and key technologies related to off-season breeding (October to January of the following year), such as precise water temperature control, appropriate spawning induction programs, and stress-resistant parent fish cultivation, are still lacking, making it impossible to achieve a stable supply of seedlings throughout the year and to support the continuous advancement of basic research; the precise breeding technology system for the complex traits of Qihe crucian carp, such as rapid growth, salt and alkali tolerance, and high quality, is not yet perfect, making it difficult to meet the industry's urgent need for superior varieties.

[0006] Against this backdrop, the development of off-season breeding technology for Qihe crucian carp has significant practical and strategic value. From an industrial perspective, this technology can break the seasonal limitations of seedling supply, overcome the seedling bottleneck in large-scale aquaculture, promote the quality improvement and expansion of the Qihe crucian carp aquaculture industry, and allow this "Henan fish brand" to go beyond Henan and reach the whole country, joining the ranks of my country's main fisheries. From a scientific research perspective, it can overcome the seasonal constraints of fertilized egg supply, providing stable experimental materials for basic research such as Qihe crucian carp germplasm innovation and molecular mechanism analysis, accelerating the transformation of scientific research results. From a resource utilization perspective, it can provide technical support for the large-scale breeding of new salt-tolerant Qihe crucian carp strains, contributing to the development of aquaculture in saline-alkali lands, expanding the space for fisheries development, and responding to the national food security strategy. From a technological innovation perspective, it can fill the technological gap in off-season breeding of locally unique gynogenetic fish, improve the precision breeding and propagation technology system for aquatic seed industry, and provide useful lessons for the industrial upgrading of similar fish species.

[0007] In summary, existing technologies can no longer meet the dual needs of high-quality development and scientific research innovation in the Qihe crucian carp industry. There is an urgent need for an off-season breeding program that adapts to the biological characteristics of Qihe crucian carp and integrates multiple technological dimensions.

[0008] The literature (Zhang Weifang. Artificial breeding technology of crucian carp in Qihe River[J]. Farmers' Consultant, 2021,(15):111-112.) published an artificial breeding technology for crucian carp in Qihe River, which includes the following steps: 1) Establishing the breeding conditions, adjusting the water quality of the breeding pond, and determining the conditions for pond breeding; 2) Breeding of broodstock, the source and selection of broodstock, and the intensive breeding of broodstock; 3) Artificial breeding, preparation before spawning, selection of broodstock, differentiation between male and female, selection of spawning pond, construction and placement of artificial fish nests, artificial spawning, artificial insemination and de-adhesion; 4) Hatching of fertilized eggs, pond hatching, water-sprinkling hatching, de-adhesion flowing water hatching; 5) Stocking of fry. Technical analysis revealed the following defects and deficiencies in the disclosed technical solution: the breeding cycle is limited to the natural breeding season, and it does not involve the design of off-season breeding technology. It cannot break through the natural breeding time limit of Qihe crucian carp from April to June, making it difficult to meet the year-round market demand for seedlings. It also cannot provide off-season experimental materials for basic research such as germplasm innovation and molecular mechanism analysis, thus restricting the large-scale development of the industry and the continuous advancement of scientific research.

[0009] The breeding of broodstock lacks a precise control plan. The specific control parameters for water temperature and light are not clearly defined, and key conditions such as the cycle and duration of water flow stimulation are not mentioned. Furthermore, no targeted maturation steps and supporting technologies are designed, making it difficult to ensure the synchronicity of gonadal development in broodstock and easily leading to insufficient reproductive cell activity.

[0010] The design of the spawning induction technology is relatively crude, and the specific ratio, injection dosage and injection method (such as single / multiple injection) of the spawning induction agent are not clearly defined. It cannot be adapted to the biological characteristics of the development of the female nucleus of the Qihe crucian carp, which may lead to problems such as low spawning induction efficiency and strong stress response of the parent fish.

[0011] The key technical parameters of the incubation process are vague, and the precise range of incubation water temperature, water quality control standards, and cycle and operation specifications for removing dead eggs are not clearly defined. Furthermore, the de-adhesion process only mentions basic operations and does not provide the specific ratio, dosage, and usage method of the de-adhesion agent (such as talc), making it difficult to ensure the stability and controllability of the hatching rate.

[0012] The technology system lacks consideration for environmental adaptability and does not involve key technologies such as stress-resistant breeding of broodstock and quality assurance of reproductive cells in off-season aquaculture environments. It is unable to cope with environmental fluctuations during non-natural breeding seasons, thus limiting the practicality and large-scale application value of the technology. Summary of the Invention

[0013] The technical problem solved by this invention is to provide a method for off-season artificial breeding of Qihe crucian carp that can obtain fertilized eggs and high-quality fry year-round.

[0014] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for off-season artificial breeding of Qihe crucian carp, the specific steps of which are as follows: Step S1, selection, intensive breeding, and maturation of broodstock: 1) Selection of broodstock: Select 2-year-old female Qihe crucian carp weighing 0.5~0.6Kg and place them in the intelligent aquaculture system at a density of 20 fish / bucket. The bucket diameter is 2m and the water depth is 1m. When the broodstock are put into the bucket, the water temperature is set to the outdoor pond temperature. Then, adjust the temperature of the intelligent aquaculture system to 6℃ every day at a rate of 3℃ / day and maintain the temperature at 6℃ for 30 days. During this period, stop feeding when the water temperature is below 14℃. After the low temperature period ends, start raising the temperature at a rate of 3℃ / day. When the water temperature reaches 14℃, start increasing the amount and frequency of feeding and adjust the light to 14 hours / day. When the water temperature reaches 22~24℃, stop raising the temperature and maintain a constant temperature. Feed them with Huifu California bass extruded compound feed containing 0.04wt% vitamin E three times a day, at 8:00, 12:00 and 18:00. Stimulate with running water once every two days for 5 minutes each time, and continue feeding for 30 days. 2) Intensive rearing of broodstock: Select 2-year-old, mature male Qihe crucian carp weighing 0.5-0.6 kg and place them in the intelligent aquaculture system at a density of 20 fish / bucket. The bucket diameter is 2m and the water depth is 1m. When the broodstock are put into the bucket, the water temperature is set to the outdoor pond temperature. Then, adjust the temperature of the intelligent aquaculture system to 6℃ every day at a rate of 3℃ / day and maintain the 6℃ state for 30 days. During this period, stop feeding when the water temperature is below 14℃. After the low temperature period ends, start raising the temperature at a rate of 3℃ / day. When the water temperature reaches 14℃, start increasing the amount and frequency of feeding and adjust the light to 14 hours / day. When the water temperature reaches 22-24℃, stop raising the temperature and maintain a constant temperature. Feed them with Huifu California bass extruded compound feed containing 0.04wt% vitamin E three times a day, at 8:00, 12:00 and 18:00. Stimulate with running water once every two days for 5 minutes each time, and continue feeding for 30 days. 3) Induced maturation: The broodstock raised in the above-mentioned centralized culture were induced to mature. The specific method was to inject each broodstock with 0.1µg / Kg of body weight of luteinizing hormone-releasing hormone A2, and at the same time adjust the water level of the culture system to 40cm; spawning was induced 10 days after maturation. Step S2: Inducing spawning in parent fish, artificial insemination, and incubation: Spawning induction in broodstock: Female broodstock are induced to spawn using a two-injection method, while male broodstock are induced to spawn using a single injection method. The specific methods are as follows: 1) Induction of spawning in female broodstock: A two-injection method was used. For the first spawning induction, each female broodstock was injected with a mixture of 0.15 mg / kg body weight of dioxin and 0.5 µg / kg body weight of luteinizing hormone-releasing hormone A2. Twelve hours later, a second spawning induction was performed, with each female broodstock injected with a mixture of 0.85 mg / kg body weight of dioxin, 2 µg / kg body weight of luteinizing hormone-releasing hormone A2, and 200 IU / kg body weight of human chorionic gonadotropin. 2) Induction of spawning in male broodstock: When the female fish undergoes a second spawning induction, the male fish will also be induced to spawn. Each male broodstock will be injected with a mixture of 0.5 mg / kg body weight of dioxin and 1.25 µg / kg body weight of luteinizing hormone-releasing hormone A2. After the injection, the broodstock will be returned to the intelligent aquaculture system in a timely manner. The water temperature of the intelligent aquaculture system will be maintained at 22~24℃ and the light will be maintained at 14 hours / day. 3) Artificial insemination: When the parent fish are found to be in heat and ready to spawn, immediately remove them for inspection. If the eggs can flow out automatically when the abdomen is gently pressed, then immediately collect the eggs artificially. Squeeze the mature eggs into a clean container. Use the same method to squeeze the sperm of the male parent fish into the container containing the eggs. Gently stir with a clean feather for about 1 to 2 minutes to ensure that the sperm and eggs are fully mixed. 4) Hatching: Slowly add water to the well-mixed fertilized eggs and stir gently; then pour in talcum powder water to remove the adhesion, and put the deadhesive fertilized eggs into the hatching system for hatching. The hatching water temperature is controlled at 24~26℃.

[0015] Furthermore, the early cultivation and maturation process of the broodstock is as follows: a batch of healthy, well-developed 2-year-old Qihe crucian carp broodstock are selected for cultivation, including low-temperature cultivation at 4-6℃ and high-temperature cultivation at 22-24℃; after cultivation, maturation is induced 10 days before spawning, specifically by injecting the cultivated broodstock with 0.1µg / Kg of fish body weight of luteinizing hormone-releasing hormone A2, while adjusting the water level of the intelligent aquaculture system to 40cm, and feeding them with Huifu California bass extruded compound feed containing 0.04wt% vitamin E.

[0016] Furthermore, the specific incubation process is as follows: 1) The day before releasing the eggs, adjust the water quality of the incubation system, keep the water temperature at 24~26℃, maintain the water level and continuous circulation, and prepare for use; 2) Collect female fish eggs and male fish sperm, and place them in an environment of 24℃ to complete artificial insemination. Dissolve 100g of talc powder (magnesium silicate) and 20-25g of salt in 10L of water and stir to form a suspension. Use this suspension to de-adhere the fertilized eggs. Each 10L of talc powder suspension can de-adhere 1-1.5Kg of Qihe crucian carp fertilized eggs. During the operation, pour the talc powder suspension into the container containing the fertilized eggs while stirring by hand. When the fertilized eggs are dispersed into particles, the de-adhesion effect is achieved. After de-adhesion, the fertilized eggs are rinsed and placed in an incubator for flowing water incubation. Maintain the incubation system temperature at 24-26℃. 3) Remove dead eggs and change the water as needed at 8:00, 12:00 and 18:00 every day to maintain the water temperature, water quality and continuous flow of the incubation system; 4) Observe the fertilized eggs daily; the embryos hatch after 45.2-53.8 hours. 5) Once the fry begin to swim horizontally, promptly transfer them to the fry rearing pond for rearing. During this period, feed them with Sheng Suo brand perch compound feed (S1) at a rate of 0.35g / 1000 fry / feed.

[0017] Compared with existing technologies, this invention has the following advantages and beneficial effects: This invention designs a reasonable off-season breeding method for Qihe crucian carp. By rationally adjusting water temperature and light duration, and innovating the use of spawning stimulants and feed, it ensures that the broodstock reach a normal physiological state for ovulation and sperm release, while also enhancing the high vitality of reproductive cells. Through innovative breeding models and screening standards, it solves the problem of aging eggs in female Qihe crucian carp. This invention has high practicality: Only an intelligent aquaculture system is needed to maintain a fixed temperature and light duration, providing periodic water flow stimulation, enabling Qihe crucian carp to spawn and release sperm normally during the non-spawning season. Through standardized spawning induction, artificial insemination, and hatching processes, a hatching rate of over 75% can be achieved, thereby increasing the economic benefits of aquaculture by over 30%. This invention is highly targeted and innovative: This invention precisely adapts to the biological characteristics of natural gynogenesis development in Qihe crucian carp, tailoring a complete off-season breeding program. By scientifically controlling flow rate and water temperature, optimizing light cycles, and innovating the formulation and application methods of spawning stimulants, combined with a special nutritional feed formula for broodstock, the technology provides dual protection for broodstock to achieve synchronized ovulation and spermation, while significantly enhancing reproductive cell activity. Coupled with innovative breeding models and broodstock selection standards, this approach fundamentally solves the industry's technical challenges of asynchronous gonadal development and insufficient reproductive cell fertilization activity in Qihe crucian carp broodstock under off-season conditions. The technology combines innovation and practicality.

[0018] Simple to operate and highly stable: By relying on the intelligent aquaculture system to achieve precise and constant control of water temperature and light duration, the natural breeding limitation of Qihe crucian carp from April to June can be broken, and stable off-season spawning and sperm release can be successfully achieved from October to January of the following year. No complicated additional equipment is required, which lowers the threshold for large-scale application.

[0019] Significant breeding efficiency and economic benefits: Using the technology of this invention, the hatching rate of fertilized eggs of Qihe crucian carp can reach more than 75%, effectively filling the gap between seedling supply and demand in summer and winter and extending the breeding cycle; at the same time, it provides stable experimental materials for basic research such as germplasm innovation and molecular mechanism analysis, helping scientific research and industry to develop in synergy, and ultimately achieving an improvement of more than 30% in the overall breeding benefits, providing core technical support for the large-scale and high-quality development of the Qihe crucian carp industry. Attached Figure Description

[0020] Figure 1 A in the diagram represents a fertilized egg of a crucian carp from the Qihe River. The arrows in the diagram indicate successfully fertilized eggs. Fertilized eggs have a transparent membrane on the outer edge and exhibit distinct animal and vegetative poles. The arrows indicate dead fertilized eggs, whose membranes are cloudy and do not have a typical animal pole. Figure 1The letter B indicates that the embryo has been incubated for 42 hours and is about to hatch. Detailed Implementation

[0021] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0022] Off-season breeding methods for Qihe crucian carp I. Experimental Methods (a) Experimental group one was propagated according to the following method: (1) Disinfection of intelligent aquaculture system and hatching system: Soak the intelligent aquaculture system and hatching system in a 5% potassium permanganate solution for 2 hours for disinfection, then rinse with clean water 4-5 times to ensure that there is basically no potassium permanganate residue in the system. Then inject fresh water and aerate to create a clean environment for the breeding and reproduction of parent fish.

[0023] (2) Early rearing of broodstock: Select healthy 2-year-old Qihe crucian carp with fully developed gonads and feed them with Qihe crucian carp compound feed (Huifu California bass extruded compound feed with added vitamin E of 0.04wt%).

[0024] (3) Selection, centralized breeding, and ripening of broodstock: 1) Select 2-year-old female Qihe crucian carp weighing 0.5-0.6 kg and place them in the intelligent aquaculture system at a density of 20 fish / bucket (bucket diameter 2m, water depth 1m). When the broodstock are introduced into the intelligent aquaculture system, the water temperature is set to the outdoor pond temperature. Then, adjust the system temperature daily (3℃ / day) to 6℃ and maintain it at 6℃ for 30 days. During this period, stop feeding when the water temperature drops below 14℃. After the low temperature period, start raising the temperature (3℃ / day). When the water temperature reaches 14℃, start increasing the feeding amount and frequency, and adjust the light exposure to 14 hours / day. When the water temperature reaches 22-24℃, stop raising the temperature and maintain a constant temperature. Feed them with Huifu California bass extruded compound feed three times a day, at 8:00, 12:00 and 18:00. Stimulate with running water once every two days for 5 minutes each time, and continue feeding for 30 days. 2) Select 2-year-old, mature male Qihe crucian carp weighing 0.5-0.6 kg and place them in an intelligent aquaculture system at a density of 20 fish per bucket (2 m in diameter, 1 m in water depth). When the broodstock are introduced into the intelligent aquaculture system, the water temperature is set to the outdoor pond temperature. The system temperature is then adjusted daily (3℃ / day) to 6℃ and maintained at 6℃ for 30 days. Feeding is stopped when the water temperature drops below 14℃. After the low-temperature period, the temperature is raised (3℃ / day). When the water temperature reaches 14℃, the feeding amount and frequency are increased, and the light intensity is adjusted to 14 hours / day. When the body temperature reaches 22-24℃, the temperature is stopped, and a constant temperature is maintained. The fish are fed Huifu California bass extruded feed supplemented with 0.04 wt% vitamin E three times a day at 8:00, 12:00, and 18:00. Stimulate the fish with running water for 5 minutes every two days for 30 consecutive days. 3) The above-mentioned parent fish were induced to mature 10 days before spawning. The specific method is to inject the parent fish with 0.1µg / Kg of fish body weight of luteinizing hormone-releasing hormone A2 and adjust the water depth of the breeding system to 40cm. Spawning was induced 10 days after maturation. (4) Induction of labor A two-injection method was used to induce spawning, with a 12-hour interval between the two injections. For the first spawning induction, female fish were injected with a mixture of 0.15 mg / kg body weight of dioxin and 0.5 µg / kg body weight of luteinizing hormone-releasing hormone A2. Twelve hours later, for the second spawning induction, each female was injected with a mixture of 0.85 mg / kg body weight of dioxin, 2 µg / kg body weight of luteinizing hormone-releasing hormone A2, and 200 IU / kg body weight of human chorionic gonadotropin. While the females were undergoing their second spawning induction, the males were also induced to spawn, each parent fish injected with a mixture of 0.5 mg / kg body weight of dioxin and 1.25 µg / kg body weight of luteinizing hormone-releasing hormone A2. After each injection, the fish were promptly returned to the intelligent aquaculture system, where the water temperature was maintained at 22-24°C and the light exposure was maintained at 14 hours / day. When the male fish is observed chasing the female fish, the female fish is removed and the eggs are manually squeezed out. The eggs are collected at the vent using a clean container. Then, the sperm is squeezed into the eggs and stirred to mix the sperm and eggs thoroughly. Water is added to the thoroughly mixed fertilized eggs, followed by talcum powder solution to remove the adhesion. The de-adhesive fertilized eggs are then placed in the incubation system for incubation, with the incubation water temperature controlled at 24~26℃.

[0025] (5) Fertilization and incubation 1) The day before induction of spawning, adjust the water quality of the incubation system, keep the water temperature at 24~26℃, maintain a certain water level and continuous circulation, and prepare for use; 2) Collect male fish sperm and female fish eggs, and mix them thoroughly in a light-proof environment at 24℃. Divide the fertilized eggs into two portions. One portion is directly scattered on prepared palm sheets and then placed in the incubation tank. The other portion undergoes de-adhesion incubation by dissolving 100g of talc (magnesium silicate) and 20-25g of salt in 10L of water, stirring to form a suspension. This suspension can be used to remove 1-1.5kg of sticky Qihe crucian carp eggs. During the operation, slowly pour the suspension into the container containing the fertilized eggs while gently stirring with a feather. When the fertilized eggs are dispersed into particles, the de-adhesion effect is achieved. After rinsing, place the eggs in an incubator for flowing water incubation, maintaining the incubation system temperature at 24-26℃. 3) Remove dead eggs at 8:00, 12:00 and 18:00 every day to maintain the water temperature and quality of the incubation system and ensure a continuous flow of water; 4) Observe the eggs every day. The fry will begin to hatch after about 45 hours and all the fry will hatch after about 60 hours. 5) When the juvenile fish hatch, feed them Sheng Suo brand bass feed (S1) in a timely manner, at a dosage of 0.35g / 1000 fish / time.

[0026] (II) Control group 1 was bred according to the following method: (1) (2) Same as experimental group one.

[0027] (3) Selection, centralized cultivation, and maturation of broodstock: Select 2-year-old female Qihe crucian carp weighing 0.5-0.6 kg and place them in the intelligent aquaculture system at a density of 20 fish / bucket (diameter 2 m, water depth 1 m). The water temperature is the same as the outdoor pond temperature and room temperature when the fish are placed in the bucket. Then, adjust the water temperature by 3°C every day to 22-24°C. Cultivate continuously for 30 days. Feed them with Huifu California bass extruded compound feed with 0.04 wt% vitamin E. Stimulate with running water for 5 minutes every two days. Strictly follow the four fixed principles to promote the further development and maturation of the gonads of the female Qihe crucian carp broodstock.

[0028] Two-year-old, mature male Qihe crucian carp weighing 0.5-0.6 kg were selected and placed in an intelligent aquaculture system at a density of 20 fish per bucket (bucket diameter 2m, water depth 1m). The water temperature was initially set at the outdoor pond temperature, and then adjusted by 3°C daily to 22-24°C for 30 consecutive days. The fish were fed Huifu California bass extruded feed supplemented with 0.04wt% vitamin E, and stimulated with running water for 5 minutes every two days. The four fixed principles were strictly followed to promote further development and maturation of the gonads in the male Qihe crucian carp broodstock.

[0029] (4) Same as experimental group one.

[0030] (5) Debonding and incubation in the same experimental group 1.

[0031] (III) Control group two was bred according to the following method: (1) (2) Same as experimental group 1; (3) Same as control group 1, but no ripening was performed 10 days before induced labor; (4) Same as experimental group 1; (5) Same as experimental group 1 in debonding and incubation.

[0032] (iv) Control group three was bred according to the following method: (1)(2)(3) Same as Experimental Group 1, but ripening is not induced 10 days before induced spawning; (4) Same as Experimental Group 1; (5) Same as Experimental Group 1 in debonding and incubation.

[0033] (v) Control group four was bred according to the following method: (1)(2)(3) Same as experimental group one.

[0034] (4) A single injection method was used to induce spawning. Female fish were injected with a mixture of 1 mg / kg body weight of dioxin, 2.5 µg / kg body weight of luteinizing hormone-releasing hormone A2, and 200 IU / kg body weight of human chorionic gonadotropin. At the same time, male fish were injected with a mixture of 0.5 mg / kg body weight of dioxin and 1.25 µg / kg body weight of luteinizing hormone-releasing hormone A2. After the injection, the parent fish were promptly returned to the intelligent aquaculture system. The water temperature of the intelligent aquaculture system was maintained at 22-24℃, and the light intensity was maintained at 14 hours / day. When the male fish were observed chasing the female fish, the female fish were removed, and the eggs were manually squeezed out. The eggs were collected at the vent using a clean container. Then, the sperm was squeezed into the eggs and stirred to mix the sperm and eggs thoroughly. Water was added to the thoroughly mixed fertilized eggs, followed by talcum powder water to remove the adhesion. The deadhesive fertilized eggs were then placed in the incubation system for incubation. The incubation water temperature was controlled at 24-26℃.

[0035] (5) Debonding and incubation in the same experimental group 1.

[0036] Note: The 30-day low-temperature cultivation period in all the above experimental groups is adjusted according to the time of off-season breeding. For example, if off-season breeding is carried out in October or November, a one-month low-temperature cultivation process is required; if off-season breeding is carried out in December or January, a low-temperature cultivation process is not required, and parent fish are directly selected and introduced into the system, and the water temperature in the parent fish pond is raised from 22~24℃ for cultivation.

[0037] II. Data Calculation The data recorded above will be calculated using the following method: Induced spawning rate = (Number of spawning fish / Total number of fish induced to spawn) * 100% Spawning rate = (Ovulation weight / Fish body weight) * 100% Fertilization rate = (Number of fertilized eggs / Total number of eggs) * 100% Hatching rate = (Number of hatched fry / Number of fertilized eggs) * 100% Hatching rate = (Number of fry / Number of hatched fry) * 100% III. Experimental Results Experimental Group 1: The induced spawning rate reached over 75%, the egg-laying rate was 11.16%, the fertilization rate was over 78%, the hatching rate was over 75%, and the emergence rate was over 75%.

[0038] Control group 1: In December 2024, December 2025, and January 2026, the spawning rate was over 70%, the egg-laying rate was 10.6%, and the fertilization rate, hatching rate, and emergence rate were basically the same as those of the experimental group.

[0039] In October and November of 2024 and 2025, the spawning rate was less than 10%, the egg-laying rate was 3.79%, the fertilization rate was 60%, the hatching rate was over 75%, and the emergence rate was 75%.

[0040] Control group 2: Induction rate 0.

[0041] Control group 3: Induction rate less than 10%, egg laying rate 3.15%, fertilization rate 70%, hatching rate over 75%, and emergence rate over 75%.

[0042] Control group 4: Induction rate less than 20%, egg laying rate 3.22%, fertilization rate 88%, hatching rate over 75%, and emergence rate over 75%.

[0043] IV. Experimental Conclusions The experimental group and the control groups differed in their broodstock rearing and spawning induction methods, but the fertilization and de-adhesion hatching conditions were the same, resulting in virtually no difference in parameters such as hatching rate and fry emergence rate. However, there were significant differences in spawning induction rate, spawning rate, and fertilization rate. Specifically, in experimental group 1, after rearing (both low and high temperatures) and then undergoing spawning induction, the spawning induction rate was over 75%, the fertilization rate was over 78%, the hatching rate after de-adhesion was over 75%, and the fry emergence rate was over 75%. When using palm fronds for hatching without de-adhesion, the hatching rate was around 65%, and the fry emergence rate was 55%. In contrast, control group 1 did not undergo low-temperature rearing but directly underwent high-temperature rearing. After rearing, spawning induction was performed, and when off-season breeding was carried out in December and January, the spawning induction rate was over 70%, the spawning rate was 10.6%, and the fertilization rate, hatching rate, and fry emergence rate were basically the same as those of the experimental group's hatching tanks. In October and November of 2024 and 2025, when off-season breeding was carried out, the spawning rate was less than 10%, the spawning rate was 3.79%, the fertilization rate was 60%, the hatching rate was 75%, and the fry emergence rate was 75%. This indicates that if off-season breeding is carried out in October and November, the broodstock needs to undergo low-temperature cultivation before normal breeding can proceed. Control group two did not undergo low-temperature cultivation, and no induction of maturation was performed before the end of high-temperature cultivation, resulting in a spawning rate of 0%. Control group three involved broodstock undergoing (low-temperature and high-temperature) cultivation, and no induction of maturation was performed after cultivation, resulting in a spawning rate less than 10%, a spawning rate of 3.15%, a fertilization rate of 70%, a hatching rate of over 75%, and a fry emergence rate of over 75%. Control group four involved broodstock undergoing (low-temperature and high-temperature) cultivation, and maturation was performed after cultivation, but spawning was induced by a single injection method, resulting in a spawning rate less than 20%, a spawning rate of 3.22%, a fertilization rate of 88%, a hatching rate of over 75%, and a fry emergence rate of over 75%.

[0044] This invention achieves the goal of off-season breeding of Qihe crucian carp by rationally setting water temperature and light exposure time, keeping the Qihe crucian carp in a state of high physiological function for a long time; and by innovating the injection method of spawning-inducing agents and the broodstock breeding technology.

[0045] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A method for off-season artificial breeding of Qihe crucian carp, characterized in that... The specific steps are as follows: Step S1, selection, intensive breeding, and maturation of broodstock: 1) Select 2-year-old female Qihe crucian carp weighing 0.5~0.6Kg and raise them in an intelligent aquaculture system at a density of 20 fish / bucket. The bucket diameter is 2m and the water depth is 1m. When the parent fish are put into the bucket, the water temperature is set to the outdoor pond temperature. Then, adjust the temperature of the intelligent aquaculture system to 6℃ every day at a rate of 3℃ / day and maintain the 6℃ state for 30 days. During this period, stop feeding when the water temperature is below 14℃. After the low temperature period ends, start raising the temperature at a rate of 3℃ / day. When the water temperature reaches 14℃, start increasing the amount and frequency of feeding and adjust the light to 14 hours / day. When the water temperature reaches 22~24℃, stop raising the temperature and maintain a constant temperature. Feed them with Huifu California bass extruded compound feed containing 0.04wt% vitamin E three times a day, at 8:00, 12:00 and 18:

00. Stimulate with running water once every two days for 5 minutes each time, and continue feeding for 30 days. 2) Select 2-year-old, mature male Qihe crucian carp weighing 0.5~0.6Kg and raise them in an intelligent aquaculture system at a density of 20 fish / bucket. The bucket diameter is 2m and the water depth is 1m. When the parent fish are put into the bucket, the water temperature is set to the outdoor pond temperature. Then, adjust the temperature of the intelligent aquaculture system to 6℃ every day at a rate of 3℃ / day and maintain the 6℃ state for 30 days. During this period, stop feeding when the water temperature is below 14℃. After the low temperature period ends, start raising the temperature at a rate of 3℃ / day. When the water temperature reaches 14℃, start increasing the amount and frequency of feeding and adjust the light to 14 hours / day. When the water temperature reaches 22~24℃, stop raising the temperature and maintain a constant temperature. Feed them with Huifu California bass extruded compound feed containing 0.04wt% vitamin E three times a day, at 8:00, 12:00 and 18:

00. Stimulate with running water once every two days for 5 minutes each time, and continue feeding for 30 days. 3) The above-mentioned broodstock were induced to mature 10 days before spawning. The specific method was to inject the broodstock with 0.1µg / Kg of fish body weight of luteinizing hormone-releasing hormone A2, and at the same time adjust the water level of the culture system to 40cm; spawning was induced 10 days after maturation. Step S2: Inducing spawning in parent fish, artificial insemination, and incubation: Spawning induction in broodstock: Female broodstock are induced to spawn using a two-injection method, while male broodstock are induced to spawn using a single injection method. The specific methods are as follows: 1) Induction of spawning in female parent fish: The first spawning induction injection was a mixture of 0.15 mg / kg fish body weight dioxin and 0.5 µg / kg fish body weight luteinizing hormone-releasing hormone A2. 12 hours later, the second spawning induction injection was a mixture of 0.85 mg / kg fish body weight dioxin, 2 µg / kg fish body weight luteinizing hormone-releasing hormone A2 and 200 IU / kg fish body weight human chorionic gonadotropin. 2) Induction of spawning in male broodstock: When the female fish undergoes a second spawning induction, the male fish is also induced to spawn by injecting a mixture of 0.5 mg / kg fish body weight of dioxin and 1.25 µg / kg fish body weight of luteinizing hormone-releasing hormone A2. After the injection, the broodstock is immediately returned to the intelligent aquaculture system. The water temperature of the intelligent aquaculture system is maintained at 22~24℃ and the light is maintained at 14 hours / day. 3) Artificial insemination: When the parent fish are found to be in heat and ready to spawn, immediately remove them for inspection. If the eggs can flow out automatically when the abdomen is gently pressed, then immediately collect the eggs artificially. Squeeze the mature eggs into a clean container. Use the same method to squeeze the sperm of the male parent fish into the container containing the eggs. Gently stir with a clean feather for about 1 to 2 minutes to ensure that the sperm and eggs are fully mixed. 4) Hatching: Slowly add water to the well-mixed fertilized eggs and stir gently; then pour in talcum powder water to remove the adhesion, and put the deadhesive fertilized eggs into the hatching system for hatching. The hatching water temperature is controlled at 24~26℃.

2. The method for off-season artificial breeding of Qihe crucian carp according to claim 1, characterized in that... The initial rearing and maturation process of the broodstock is as follows: a batch of healthy, well-developed 2-year-old Qihe crucian carp broodstock are selected for rearing, including low-temperature rearing at 4~6℃ and high-temperature rearing at 22~24℃; after the rearing is completed, maturation is induced 10 days before spawning. The specific method is to inject the reared broodstock with 0.1µg / Kg of fish body weight of luteinizing hormone-releasing hormone A2, while adjusting the water level of the intelligent aquaculture system to 40cm. During this period, the fish are fed Huifu California bass extruded compound feed containing 0.04wt% vitamin E.

3. The method for off-season artificial breeding of Qihe crucian carp according to claim 1, characterized in that... The specific incubation process is as follows: 1) The day before releasing the eggs, adjust the water quality of the incubation system, keep the water temperature at 24~26℃, maintain the water level and continuous circulation, and prepare for use; 2) Collect female fish eggs and male fish sperm, and place them in an environment of 24℃ to complete artificial insemination. Dissolve 100g of talc powder (magnesium silicate) and 20-25g of salt in 10L of water and stir to form a suspension. Use this suspension to de-adhere the fertilized eggs. Each 10L of talc powder suspension can de-adhere 1-1.5Kg of Qihe crucian carp fertilized eggs. During the operation, pour the talc powder suspension into the container containing the fertilized eggs while stirring by hand. When the fertilized eggs are dispersed into particles, the de-adhesion effect is achieved. After de-adhesion, the fertilized eggs are rinsed and placed in an incubator for flowing water incubation. Maintain the incubation system temperature at 24-26℃. 3) Remove dead eggs and change the water as needed at 8:00, 12:00 and 18:00 every day to maintain the water temperature, water quality and continuous flow of the incubation system; 4) Observe the fertilized eggs daily; the embryos hatch after 45.2-53.8 hours. 5) Once the fry begin to swim horizontally, promptly transfer them to the fry rearing pond for rearing. During this period, feed them with Sheng Suo brand perch compound feed (S1) at a rate of 0.35g / 1000 fry / feed.

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