A breeding method for Schizothorax fasciatus

Abstract

This application discloses a method for breeding *Schizothorax fasciatus*, comprising the following steps: maturation and cultivation of wild-caught first-generation fry; selection of breeding broodstock from the matured wild-caught first-generation fry, followed by intensive broodstock cultivation and water flow stimulation to promote gonadal development; selection of *Schizothorax fasciatus* parent fish; induced spawning by injecting a spawning stimulant into the broodstock for artificial insemination to obtain fertilized eggs; hatching the fertilized eggs; and cultivating the hatched fry, followed by fertilization and water enrichment cultivation of the larvae. The spawning rate of *Schizothorax fasciatus* obtained by this method is 70–100%, the fertilization rate is 65–95%, and the hatching rate is 52–75%.

Description

Technical Field

[0001] This application belongs to the field of freshwater fish breeding technology, specifically relating to a breeding method for Schizothorax fasciatus. Background Technology

[0002] The davidi (Schizothorax davidi) belongs to the Cyprinidae family, Schizothorax subfamily, and Schizothorax genus. In the past decade or so, the wild population of the davidi has declined sharply, and its distribution area has shrunk considerably, necessitating a breeding technique to improve its hatching rate. Summary of the Invention

[0003] The purpose of this application is to provide a method for breeding Schizothorax fasciatus and to establish an artificial breeding population of Schizothorax fasciatus, which can solve the above-mentioned technical problems.

[0004] This application provides a method for breeding Schizothorax fasciatus, including the following steps:

[0005] Wild-type F1 maturation and breeding;

[0006] Breeding broodstock were selected from wild-caught first-generation broodstock after maturation and cultivation, and then subjected to enhanced broodstock cultivation. At the same time, water flow stimulation was applied to promote gonadal development.

[0007] Screening for broodstock of the schizothorax fish;

[0008] Inducing spawning involves injecting spawning stimulants into broodstock of the Schizothorax bream and then artificially inseminating them to obtain fertilized eggs.

[0009] The fertilized eggs obtained after hatching;

[0010] After hatching, the fry are raised in fertilized water.

[0011] In some embodiments, the culture water used for the maturation and cultivation of the first generation of wild offspring has the following characteristics: water temperature of 15.0–18.0℃, pH of 7.9–8.5, and dissolved oxygen content of 9.1–10.5 mg / L.

[0012] In some embodiments, the maturation of the wild-type progeny includes feeding a first feed with a protein content of 35-37%.

[0013] In some embodiments, the flow rate of the water stimulation is 0.1-0.3 m / s.

[0014] In some embodiments, a second feed is administered during the broodstock enhancement process, the second feed having a protein content of not less than 38%.

[0015] In some embodiments, the second feed is given at least twice a day, with each feeding amount being 1% to 2% of the broodstock's body weight.

[0016] In some embodiments, the enhanced parent fish rearing includes reducing the amount of feed and increasing the flow rate before spawning.

[0017] In some embodiments, the parental screening includes:

[0018] Female fish selection criteria: Female fish must be mature individuals aged 5 years or older, with a weight range of 2.5–3.5 kg and a body length range of 45–60 cm;

[0019] Male fish selection: Male fish must be individuals aged 3 years or older, with a weight range of 1.2–1.8 kg and a body length range of 35–45 cm.

[0020] In some embodiments, the oxytocin includes dapoxetine, luteinizing hormone-releasing hormone A2, and domperidone.

[0021] In some embodiments, the spawning induced injection for the female fish includes a first injection and a second injection. The first injection accounts for one-third of the total spawning induced injection, and the second injection accounts for two-thirds of the total spawning induced injection. The interval between the two injections is 15-20 hours, and the spawning effect lasts for 20-26 hours. The dosage of the spawning induced agent is: 1200-1500 IU / kg of estradiol, 8-12 μg / kg of luteinizing hormone-releasing hormone A2, and 5-9 mg / kg of domperidone.

[0022] The injection dosage of oxytocin for the male fish was: 600-750 IU / kg of estradiol, 4-6 μg / kg of luteinizing hormone-releasing hormone A2, and 2.5-4.5 mg / kg of domperidone.

[0023] In some embodiments, the incubation includes: micro-flow incubation at 0.15 to 0.25 m / s, followed by membrane removal before the seedlings begin to emerge from the membrane, while simultaneously reducing the amount of water entering the incubation chamber.

[0024] In some embodiments, the cultivation includes seedling cultivation, which includes: placing the seedlings after the fertilized eggs have hatched into membranes at the bottom of the hatching basin, using a siphon method to suck the seedlings out into the large basin, placing the seedlings at a density of one layer, gently fanning the water every 1-2 hours, and feeding them egg yolk or ultrafine egg brine shrimp every 2-3 hours for 2-3 consecutive days. As the pigment on the surface of the fish fry gradually deepens, they can be transferred to the pond for fertilization and cultivation.

[0025] In some embodiments, the cultivation includes fry cultivation, which includes: preparing pond fertilized water, fry fertilized water cultivation, and fry clear water cultivation.

[0026] In some embodiments, the pond fertilization includes: fermenting the bio-fertilizer and then evenly sprinkling it on the bottom of the feed cultivation pond, controlling the water level at 40-50cm, while observing the changes in the pond water color and making adjustments, gradually deepening the pond water level and controlling the water body at 80-100cm.

[0027] The seedling fertilization and water cultivation includes: removing predatory organisms by netting; releasing the fry into the pond when the live food in the rearing pond reaches its peak after the fry have been swimming horizontally for 2-3 days; adding fresh water to the pond to adjust the temperature difference between the pond water and the temporary holding water; feeding the fry with soybean milk and yeast twice a day; and feeding the fry for the first time after 10-15 days when the live food decreases, continuing this feeding for 50-60 days.

[0028] The seedling cultivation in clear water includes: when the fry reach an average total length of 2.3-3.5cm in fertile water, they are transferred to a second feeding. After successful transfer, the fry are transferred to a clear water pond by netting. During the transfer, the fry are disinfected by soaking in 3-5% sea salt solution for 5-10 minutes before being placed in the clear water pond.

[0029] In some embodiments, the disease control measures include the control of water mold, the control of wheelworm, and the control of melon worm.

[0030] In some embodiments, the water flow velocity is controlled at 0.3-0.8 m / s during the pre-labor induction phase and at 0.8-2 m / s during the labor induction phase.

[0031] The beneficial effects of this application are as follows: A method for breeding *Schizothorax fasciatus* includes the following steps: maturation and cultivation of wild-caught first-generation fry; enhanced broodstock cultivation: selecting breeding broodstock from the matured wild-caught first-generation fry and subjecting them to enhanced broodstock cultivation, while simultaneously stimulating water flow to promote gonadal development; screening for *Schizothorax fasciatus* parent fish; induced spawning: injecting spawning-inducing agents into the *Schizothorax fasciatus* parent fish for artificial insemination to obtain fertilized eggs; hatching the fertilized eggs; cultivating the hatched fry; and then fertilizing the fry in fertile water culture. This breeding method achieves a spawning induction rate of 70-100%, a fertilization rate of 65-95%, and a hatching rate of 52-75%. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of the breeding method described in this application;

[0034] Figure 2 This is a flowchart of the water flow control in this application;

[0035] Figure 3 This is a schematic diagram of the water tank structure in this application. Detailed Implementation

[0036] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc. are used only as illustrative purposes and do not impose numerical requirements or establish an order. Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and conciseness and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range. Additionally, whenever a numerical range is specified in this document, it means that any referenced number (fraction or integer) within the range is included.

[0037] To solve the problem of breeding *Schizothorax fasciatus*, such as Figure 1 As shown, this application provides a method for breeding Schizothorax fasciatus, including the following steps: maturation and cultivation of wild first-generation offspring; enhanced broodstock cultivation: selecting breeding broodstock from the matured wild first-generation offspring and conducting enhanced broodstock cultivation, while simultaneously stimulating water flow to promote gonadal development; screening Schizothorax fasciatus broodstock; induced spawning: injecting spawning stimulants into the Schizothorax fasciatus broodstock for artificial insemination to obtain fertilized eggs; hatching the fertilized eggs; cultivating the hatched fry, and then fertilizing the resulting larvae; disease control is required during the cultivation process.

[0038] In some embodiments, over 3,000 wild-bred first-generation schizothorax bream were used as replacement broodstock. For example... Figure 3 As shown, the rearing pond 100 is a rectangular cement pond, 15.0m long, 8.0m wide, and 1.5m deep. During daily rearing, the water depth is maintained between 1.0 and 1.2m. A water inlet pipe 101 is installed on one side of the rearing pond 100. Figure 3As shown, an inlet pipe 101 is installed on the first side 102 of the cultivation tank 100, and a drain hole 103 is provided at the bottom of the cultivation tank 100. The drain pipe connected to the drain hole 103 leads to a drainage ditch outside the cultivation tank. Pumps are installed at the four corners of the cultivation tank 100 to control the flow rate in the cultivation tank 100. In some embodiments, the two water pumps installed at both ends of the first side 102 are the first water pumps 104, and the two water pumps installed at both ends of the second side 105 opposite to the first side 102 are the second water pumps 106. The distance between the first water pumps 104 and the bottom of the cultivation tank 100 is less than the distance between the second water pumps 106 and the bottom of the cultivation tank 100. In some embodiments, the distance between the first water pumps 104 and the bottom of the cultivation tank 100 is h1, and the distance between the second water pumps 106 and the bottom of the cultivation tank 100 is h2, where h1 < h2 ≤ 3h1, such as h2 = 2h1. In some specific applications, the distance between the first water pump 104 and the bottom of the cultivation tank 100 is 0.5m, and the distance between the second water pump 106 and the bottom of the cultivation tank 100 is 1m. Furthermore, the operating power of the first water pump 104 is P1, and the operating power of the second water pump 106 is P2, satisfying: P1 < P2 ≤ 3P1, such as P2 = 2P1. This application further controls the flow rate of water entering and leaving the two pumps by controlling the difference in power between the first water pump 104 and the second water pump 106, thus creating different water flow environments in the cultivation tank 100. In some specific embodiments, P1 is 500–600W, and P2 is 1000–1200W, such as P1 being 550W and P2 being 1100W. This application involves installing water pumps at the diagonal corners of a square pond to create an asymmetrical, circular water flow. This ultimately creates a complex micro-water flow environment in the rearing pond 100. While avoiding stress on the fish and not affecting its physiological and biochemical indicators, this approach improves the survival rate and hatching rate of the reared fish.

[0039] The flow rate of this application is obtained by testing as follows: four flow meters are installed at the center of the four sides of the cultivation tank 100, and the average flow rate obtained by the flow meters is the water flow rate of this application.

[0040] In some embodiments, the aquaculture water is mountain stream water with an annual water temperature of 15.0–18.0℃, a pH value of 7.9–8.5, and a dissolved oxygen content of ≥9.1–10.5 mg / L.

[0041] In some embodiments, wild-caught first-generation broodstock of *Schizothorax fasciatus* are routinely fed a first-generation feed containing 35-37% protein. The feed amount is 1%-2% of the broodstock's body weight, and feeding is done daily between 8:00 and 8:30 AM. To ensure water quality, the broodstock pond is cleaned every 3-5 days. Starting in mid-April, the water inflow is gradually adjusted.

[0042] In some embodiments, the first feed is extruded compound feed for chub fish No. 0, with a feed pellet diameter of 4.0 mm and a crude protein content of ≥35 wt%. The main components include: fish meal, peeled soybean meal, wheat, flour, rapeseed meal (type 200), cottonseed meal, calcium dihydrogen phosphate, mineral elements and vitamins, and are sourced from Sichuan Tesjia Feed Co., Ltd.

[0043] In some specific embodiments, the parent fish are fed a first feed with a protein content of 35% daily from January to April, with the feeding amount being 1% to 2% of the parent fish's body weight. Daily feeding is done from 8:00 to 8:30 in the morning, and the pond is cleaned once every 5 to 7 days. The water exchange rate can reach 9 to 12 cubic meters per hour.

[0044] In some embodiments, the flow rate of the water stimulation during the enhanced breeding of broodstock is 0.1-0.3 m / s; this application promotes gonadal development by increasing the water stimulation during the enhanced breeding of broodstock.

[0045] In some embodiments, a second feed is given during the broodstock enhancement process. The protein content of the second feed is not less than 38%. The second feed is given at least twice a day, and the amount given each time is 1% to 2% of the broodstock body weight. The broodstock enhancement culture includes reducing the amount of feed and reducing the flow rate before spawning.

[0046] In some embodiments, the second feed is catfish extruded compound feed No. 0, with a feed pellet diameter of 4.0 mm and crude protein ≥38 wt%. The main components include: fish meal, peeled soybean meal, wheat, flour, rapeseed meal (type 200), cottonseed meal, calcium dihydrogen phosphate, mineral elements and vitamins, sourced from Sichuan Tesjia Feed Co., Ltd.

[0047] In some embodiments, the second feed is fed between 8:00 and 8:30 in the morning and between 17:00 and 17:30 in the afternoon.

[0048] In some embodiments, water flow control for enhanced parent fish rearing includes the following steps:

[0049] In mid-April, the water flow velocity was controlled at 0.05-0.1 m / s, and the flushing time was 24 hours a day without interruption.

[0050] From May to June, the water flow velocity is controlled at 0.1 to 0.3 m / s, and the flushing time is 24 hours a day without interruption.

[0051] During July and August, the water flow velocity should be controlled at 0.3 to 0.8 m / s, and the flushing time should be 6 to 12 hours every day or every other day (1 to 2 days).

[0052] In September, the water flow rate is controlled between 0.8 and 2 m / s, and the flushing time is 24 hours a day without interruption.

[0053] Table 1. Water flow control parameters for intensive broodstock rearing

[0054]

[0055] In some embodiments, if the food intake is significantly reduced in mid-September if the weather and other conditions are normal, it indicates that artificial labor induction can be performed. Reduce watering 10 days before labor to prevent spontaneous labor, and stop feeding 3-5 days before labor induction.

[0056] This application has successfully bred nearly 2,000 mature wild first-generation broodstock and replacement broodstock using the above methods, with a survival rate of over 75% during the breeding and domestication process.

[0057] Sexually mature and well-developed broodstock of the Schizothorax fasciatus exhibit obvious secondary sexual characteristics during the breeding season.

[0058] Male fish have prominent "buzzing" markings on their snouts, and milky-white semen flows out when the vent is gently pressed. The scales on the caudal peduncle are slightly upturned and feel rough to the touch, with a slightly prickly feel. Female fish have noticeably rough scales on the caudal peduncle, a swollen and soft abdomen, and a prominent, reddish genital opening. Based on these criteria, parent selection includes: selecting females: mature individuals over 5 years old, weighing 2.5–3.5 kg and measuring 45–60 cm in length; selecting males: individuals over 3 years old, weighing 1.2–1.8 kg and measuring 35–45 cm in length.

[0059] Using the above methods, selectively selected male and female parent fish with well-developed glands, good physical condition, and no damage to their body surface were used for fully artificial breeding experiments. The spawning induced by the spawning induced agents included hCG, luteinizing hormone-releasing hormone A2 (LRH-A2), and domperidone (DOM).

[0060] The injection dosage of oxytocin for female fish is as follows: 1200-1500 IU / kg of oxytocin, 8-12 μg / kg of luteinizing hormone-releasing hormone, and 5-9 mg / kg of domperidone.

[0061] The spawning induction for female fish includes a first injection and a second injection. The first injection accounts for one-third of the total spawning induction, and the second injection accounts for two-thirds. The interval between the two injections is 15-20 hours, and the spawning effect lasts for 20-26 hours. During spawning induction, the water temperature in the pond is controlled at 16.0±0.5℃.

[0062] The injection dosage of oxytocin for male fish is as follows: 600-750 IU / kg of oxytocin, 24-6 μg / kg of luteinizing hormone-releasing hormone A, and 2.5-4.5 mg / kg of domperidone.

[0063] In some embodiments, artificial insemination refers to dry artificial insemination. Specifically, dry artificial insemination includes the following steps: Male and female parent fish are placed separately in anesthesia tanks for short-term anesthesia. The anesthetic used is MS-222 powder (research grade), and the anesthesia time is generally 5-8 minutes. The female fish is anesthetized until her gill covers slightly close and her mouth is slightly open. After gently touching the female fish and she does not move, the next step can proceed. The male fish is anesthetized for 2-3 minutes. Then, artificial ovulation and sperm collection are performed. This process requires protection from light, and the temperature of the container for collecting the eggs must be the same as the fish's body temperature. The obtained eggs and sperm need to be artificially inseminated indoors promptly. After the obtained eggs and sperm are thoroughly mixed with chicken feathers, they need to stand for 2-3 minutes, followed by 5-6 washes until there are no blood clots or excess semen in the eggs, and the water is clear. They are then placed in a plastic basin with a slight water flow, and after fully absorbing water and expanding, they are counted and transferred to an incubation device for slight water flow incubation.

[0064] In some embodiments, the flow rate of micro-flow incubation is controlled at 0.15 to 0.25 m / s. Before the seedlings begin to emerge from the membrane, the membrane is removed, and the water intake for incubation is reduced, with the water flow rate controlled at 0.05 to 0.08 m / s.

[0065] In some embodiments, the specific steps of artificial incubation include: placing fertilized eggs in incubation sieves and incubation bottles for incubation. The fertilized eggs are evenly spread in the incubation sieves, with approximately 20,000 to 25,000 fertilized eggs per sieve; each incubation bottle contains approximately 30,000 to 35,000 fertilized eggs. Incubation is carried out using a micro-flow of water at a rate of 0.15 to 0.25 m / s throughout, with constant monitoring of water flow changes. During incubation, dead eggs begin to appear around the late gastrulation stage. At this time, unfertilized eggs and poorly developed fertilized eggs need to be promptly removed from the incubation sieves until the pre-emergence stage. Before the seedlings begin to emerge from the membrane, the incubation sieves need to be transferred to temporary rearing trays for molting, while simultaneously reducing the water inflow during incubation; the water inflow during molting is 0.05 to 0.08 m / s.

[0066] Table 2. Water flow velocity control parameters for *Schizothorax fasciatus*

[0067] period Flow velocity range m / s Before the period of enhanced breeding of parent fish 0.05-0.1 Broodstock Enhancement Breeding Period 0.1-0.3 Pre-labor induction 0.3-0.8 Induction of labor 0.8-2.0 Micro-flow incubation period 0.15～0.25 Demolding period 0.05～0.08 Daily cultivation 0.05～0.1

[0068] This application requires seedling cultivation, larval rearing, and disease control after hatching.

[0069] In some embodiments, seedling cultivation employs the following steps: After hatching, the fertilized eggs are temporarily held in a temporary holding basin after approximately 180 hours. Seedling collection: Newly hatched seedlings are placed at the bottom of the hatching basin and siphoned out into a larger basin. After repeated washing to remove eggshells, dead seedlings, and impurities, they are placed in a temporary holding basin with a diameter of 1m. The seedling holding basins should be placed at a density where the seedlings are laid out in a single layer. The water should be gently agitated every 1-2 hours to prevent the seedlings from overlapping and suffocating. After hatching, the fry are transferred to temporary rearing trays and lie flat on the bottom of the trays, growing by absorbing nutrients (egg yolk). During the absorption of nutrients, a small number of fry can be seen floating in the water. After about 150 hours, the rate of swimming horizontally can reach more than 80%. At this time, they can be fed egg yolk filtered through a 100-mesh silk screen or ultra-fine brine shrimp at 2-3 hour intervals for 2-3 consecutive days. As the pigment on the fry's body surface gradually deepens, they can be transferred to ponds for fertilization and rearing.

[0070] In some embodiments, larval rearing includes:

[0071] Prepare the pond fertilization water: After fermenting the bio-fertilizer, evenly sprinkle it at the bottom of the feed cultivation pond (ideally with 10-20cm of silt at the bottom), and control the water level at approximately 40-50cm. During the cultivation process, observe the changes in the pond water color and adjust accordingly, gradually deepening the water level to maintain a depth of 80-100cm. The well-cultivated water will contain abundant live food, such as rotifers, cladocerans, and copepods.

[0072] Fry rearing and fertilization: Before stocking the fish fry, the live feed pond should be netted to remove predatory organisms such as dragonfly larvae, improving the survival rate of the fry. After the fry have been swimming horizontally for 2-3 days and the live feed in the rearing pond has reached its peak, the fry can be stocked. Before stocking, various indicators of the pond water should be monitored, including ammonia nitrogen, nitrite, pH, and hydrogen sulfide. Once these indicators are within safe ranges, fresh water should be added to the pond to adjust the temperature difference between the pond water and the temporary holding water. Stocking should be carried out on a sunny morning. After stocking the fish, test the water quality indicators every 1-2 days and perform microscopic examination every 5-7 days. Observe the activity of the fish fry and changes in water color and weather. To ensure that the fish fry have enough food organisms, feed them soybean milk and yeast twice a day, at 8 am and 6 pm. About 10-15 days after stocking the fish fry, as the amount of food organisms decreases, the first feeding can be carried out. The feed used for the first feeding should have a protein content of ≥50% and should be fed for 50-60 days.

[0073] In some implementations, the amount of soybean milk added is 1 g / m³ of dried soybeans per cubic meter of pool water. 3 .

[0074] In some implementations, the yeast addition amount is 1 g / m³ of dry yeast per cubic meter of pool water. 3 .

[0075] In some embodiments, the feed used for the first feeding transition is: perch extruded compound feed (8850) powder, the main components of which are: fish meal, high gluten flour, imported fish oil, fermented soybean meal, yeast hydrolysate, calcium dihydrogen phosphate, mineral elements and vitamins, wherein crude protein ≥ 50 wt%.

[0076] Seedling rearing in clear water: When the fish fry reach an average total length of 2.3–3.5 cm in fertile water, they are transferred to a second feeding tank. After successful transition, the fry are transferred to a clear water tank via netting and fed again. During the transfer, the fry need to be disinfected by soaking in 5% sea salt solution for 10 minutes before being placed in the clear water tank. The feed used during the clear water rearing process is shown in Table 3.

[0077] Table 3. Composition of Feed for Seedling Cultivation in Clear Water

[0078]

[0079] This application increases the survival rate and quality of fish fry by adjusting the feed formula during the clear water cultivation process to adapt to the development process of the fish fry.

[0080] In some embodiments, disease control includes the control of saprolegniasis, trichodiniasis, and ichthyophthirius multifiliis. Specifically, during the rearing of schizothorax fry, common diseases such as saprolegniasis, trichodiniasis, ichthyophthirius multifiliis, Gyrodactylus, and Dactylogyrus can be controlled using existing methods. For example, the following methods can be used for the control of these diseases:

[0081] Control of Saprolegniasis: Saprolegnia can proliferate during the training of fish fry in nets and during pond transfers, under conditions of predatory organisms and low water temperatures. Filamentous white mold can be seen on the surface of the fish's body. A solution of 0.5 ppm-1 ppm of salicylic acid can be applied by spraying and soaking for 1 hour, repeating for 3-5 days. Then, a solution of 0.5-1 ppm chlorine dioxide can be applied to the entire pond, soaking for 1 hour, followed by water changes. This process can be repeated for 3 consecutive days.

[0082] Control of Trichodina: During aquaculture, if fish fry are observed swimming wildly in the water, circling, swimming alone, or not congregating around the pond, microscopic examination can be performed. Microscopic examination of the fins and caudal peduncle will reveal a horseshoe-shaped macronucleus and a round or oval micronucleus within the worm's body. The worm can move by undulating the ring-shaped structure, resembling a wheel, indicating Trichodina. It can be treated by spraying 0.5 ppm of a solution of Mannichine (plant extract) and soaking for 30 minutes, repeating for 2-3 days. Then, disinfect by spraying 0.5 ppm of chlorine dioxide and soaking for 1 hour, changing the water, repeating for 3 consecutive days.

[0083] Control of Ichthyophthirius multifiliis (white spot disease): During the aquaculture process, if fish fry are found to be sluggish, swimming at the surface, with white cysts on their bodies, and producing large amounts of mucus on their fins and caudal peduncle; and if the diseased fish tend to gather at the water inlet and push against the water, it can be diagnosed as Ichthyophthirius multifiliis. A solution of 210g chili powder and 100g dried ginger slices, decocted into 25kg, can be sprayed throughout the pond once a day for 3-5 consecutive days. Afterward, spray with 0.5ppm chlorine dioxide, soak for 1 hour, change the water, and repeat for 3 consecutive days.

[0084] Example 1: The effect of feed administration on induced fertilization rate

[0085] Wild-caught first-generation fry maturation and cultivation: From January to April 2018, feed them a first feed with a protein content of 35% at a rate of 1% of the broodstock's body weight. Daily feeding is done from 8:00 to 8:30 in the morning. Clean the pond every 5 to 7 days. The water temperature is 15.0 to 18.0℃, the pH is 7.9 to 8.5, the dissolved oxygen content is 9.1 to 10.5 mg / L, and the water flow rate in the rearing pond is controlled at 0.05 m / s.

[0086] In mid-May, the selected first-generation wild-caught schizothorax bream were placed in a rearing pond of 100 for intensive parent stock rearing. They were fed a second feed with a protein content of ≥38%, twice a day (8:00-8:30 AM and 5:00-5:30 PM), with the pond cleaned every three days and the water flow rate maintained at 0.1 m / s. Ten days before spawning, the feeding frequency and amount were reduced, or feeding was stopped for three days. From mid-May to September, the water flow was increased, with continuous flushing throughout the day, maintaining a flow rate of 0.5 m / s, until the parent fish were ready for artificial breeding. One month before spawning, the gonadal development was checked regularly. If, in mid-September, weather and other conditions were normal but feeding significantly decreased, artificial spawning could be induced. Ten days before spawning, flushing was reduced to prevent spontaneous spawning, and feeding was stopped three days before spawning induction.

[0087] Comparative Example 1: The cultivation method is the same as in Example 1, except that the parent fish are fed the first feed during the intensive cultivation stage, while the rest of the cultivation method is the same as in Example 1.

[0088] Table 4

[0089] Induction rate (%) Example 1 ≥65％ Comparative Example 1 25％～35％

[0090] Note: The statistical method for induced spawning rate is as follows: when the breeding female parent fish are captured, the ratio of the number of spawning parent fish to the total number of breeding female parent fish is counted, and the half-spawning female fish are converted into full-spawning female fish as the unit of total spawning.

[0091] The induced spawning rate is a statistical result of different culture ponds. For each culture method, the number of culture ponds counted is no less than 3.

[0092] Example 2: The cultivation method is the same as in Example 1, except that from mid-May to June, the water flow is increased, with continuous flushing throughout the day, and the flow rate is controlled at 0.2 m / s; from July to August, the water flow rate is controlled at 0.5 m / s, and the flushing time is controlled at 8 hours per day, until the parent fish are artificially bred. The gonadal development is checked regularly one month before spawning. Starting in September, the flow rate is controlled at 1 m / s, with continuous flushing throughout the day. If, in mid-September, the fish's normal feeding amount significantly decreases due to weather or other factors, artificial spawning can be induced. Flushing is reduced 10 days before spawning to prevent spontaneous spawning, and feeding is stopped 3 days before induced spawning.

[0093] Comparative Example 2: The cultivation method is the same as in Example 1, except that during the broodstock cultivation stage, from April to September until artificial spawning, the flow rate of the water in the cultivation pond is controlled at 0.05 m / s.

[0094] Table 5

[0095] Induction rate (%) Example 2 ≥75％ Comparative Example 2 35％

[0096] Example 3: Artificial breeding of Schizothorax fasciatus

[0097] (1) Enhanced breeding of parent fish: The breeding steps are the same as in Example 2.

[0098] (2) Parental selection: Select parent fish of the schizothorax species. Female fish are mature individuals aged 5 years or older with an average weight of 3.0 kg and an average body length of 55 cm. Male fish are individuals aged 3 years or older with an average weight of 1.5 kg and an average body length of 40 cm.

[0099] (3) Artificial spawning induction: The spawning induction agent used was a mixture of three drugs: hCG, luteinizing hormone-releasing hormone A2 (LHRH-A2) for injection, and domperidone (DOM) for injection. The spawning induction dosage was (HCG 1200 IU + LHRH-A2 8 μg + DOM 5 mg) / kg. The injection site was the abdominal cavity at the base of the pectoral fin, divided into two injections. The first injection was 1 / 3 of the total dose, and the second injection was 2 / 3 of the total dose. At a water temperature of 16.0 ± 0.5℃, the interval between the two injections was 15 hours, and the spawning effect lasted for 20 hours. Male fish were injected once, with the dosage halved compared to that of female fish. Artificial insemination was performed according to the dry insemination method. Male and female parent fish are placed separately in anesthesia tanks for short-term anesthesia using MS-222 powder (research grade). Anesthesia time is generally 5 minutes. For females, anesthesia is indicated by slight closure of the gill covers and a slightly open mouth. Once the female remains still upon gentle touch, the next step can proceed. Males are anesthetized for 2-3 minutes. Artificial ovulation and sperm collection are then performed, avoiding light during this process. The temperature of the container for collecting the eggs must be the same as the fish's body temperature. The collected eggs and sperm are then artificially inseminated indoors immediately. The eggs and sperm are thoroughly mixed with chicken feathers and allowed to stand for 2-3 minutes, followed by 5-6 washes until the eggs are free of blood clots and excess semen, and the water is clear. The eggs are then placed in a plastic basin with a slight water flow and allowed to fully absorb water and swell before being counted. Finally, they are transferred to an incubation device for incubation in a slight water flow.

[0100] (4) Artificial incubation: Fertilized eggs are placed in incubation sieves and incubation bottles for incubation. The fertilized eggs are evenly spread in the incubation sieves, with approximately 20,000 to 25,000 fertilized eggs per sieve; each incubation bottle contains approximately 30,000 to 35,000 fertilized eggs. Incubation is carried out using a micro-flow of water at 0.15 to 0.25 m / s throughout the process, with constant monitoring of water flow changes. During incubation, dead eggs begin to appear around the late gastrulation stage. At this time, unfertilized eggs and poorly developed fertilized eggs need to be promptly removed from the incubation sieves until the pre-emergence stage. Before the seedlings begin to emerge from the membrane, the incubation sieves need to be transferred to temporary rearing trays for molting, while simultaneously reducing the incubation water flow to 0.05 to 0.08 m / s.

[0101] (5) Seedling rearing: After hatching from the fertilized eggs for about 180 hours, they are temporarily raised in temporary rearing basins. Seedling collection: The newly hatched seedlings are placed at the bottom of the hatching basin and siphoned out into a large basin. They are then washed several times to remove eggshells, dead seedlings, and impurities, and then placed in temporary rearing basins with a diameter of 1m. The seedlings should be placed in a single layer in the temporary rearing basins. The water should be gently fanned every hour to prevent the seedlings from overlapping and suffocating. After hatching, the seedlings transferred to the temporary rearing basins lie flat on the bottom of the basin and grow by absorbing nutrients (yolk). During the absorption of nutrients, a small number of fry can be seen floating in the water. After about 150 hours, the floating rate can reach more than 80%. At this time, they can be fed egg yolk filtered through a 100-mesh silk screen or ultra-fine brine shrimp every 2 hours for 2 consecutive days. The pigment on the surface of the fry gradually deepens, and they can then be transferred to ponds for fertilization and rearing.

[0102] (6) Larval rearing:

[0103] Prepare the pond fertilization water: After fermenting the bio-fertilizer, evenly sprinkle it at the bottom of the feed cultivation pond, and control the water level at about 40-45cm. During the cultivation process, observe the changes in the pond water color and adjust accordingly, gradually deepening the pond water level to maintain a depth of 70-80cm. The well-cultivated water will contain a large amount of live food, such as rotifers, cladocerans, and copepods.

[0104] Seedling rearing and fertilization: Before stocking the fish fry, the live feed pond should be netted to remove predatory organisms such as dragonfly larvae, improving the survival rate of the fry. Two days after the fry begin swimming horizontally, when the live feed in the rearing pond reaches its peak, the fry can be stocked. Before stocking, various indicators of the pond water should be monitored, including ammonia nitrogen, nitrite, pH, and hydrogen sulfide. If these indicators are within safe ranges, fresh water should be added to the pond to adjust the temperature difference between the pond water and the temporary holding water. Stocking should be carried out on a sunny morning. After stocking, water quality indicators should be tested every day and microscopic examination should be performed every 5 days. Observe the activity of the fry and changes in water color and weather. To ensure that the fry have enough food organisms, feed them soybean milk and yeast twice a day, at 8 am and 6 pm. About 10 days after stocking, as the amount of food organisms decreases, the first feeding can be carried out. The first feeding is perch extruded compound feed (8850) powder, the main components of which are: fish meal, high gluten flour, imported fish oil, fermented soybean meal, yeast hydrolysate, calcium dihydrogen phosphate, mineral elements and vitamins, of which crude protein ≥50wt%.

[0105] Seedling rearing in clear water: When the fry reach an average total length of 2.3–3.5 cm in fertile water, they are transferred to a second feeding tank. After successful transition, the fry are transferred to a clear water tank via netting and fed again. During the transfer, the fry need to be disinfected by soaking in 5% sea salt solution for 10 minutes before being placed in the clear water tank. The feed used during the clear water rearing process is shown in Table 3.

[0106] Prevention and control of saprolegniasis: In 2018, saprolegniasis proliferated during the netting and transfer of fish fry to different ponds. Filamentous white mold was visible on the fish's body surface. It can be treated by spraying 0.5 ppm of salicylic acid solution and soaking for 1 hour, repeating for 3 consecutive days. Then, spray the entire pond with 0.5 ppm chlorine dioxide solution and soak for 1 hour, changing the water. Repeat this process for 3 consecutive days.

[0107] Example 4: Artificial breeding of Schizothorax fasciatus

[0108] The artificial breeding of *Schizothorax spp.* using the method described in Example 3 in 2019 differed in that, during the rearing process in 2019, it was observed that the fry swam wildly in the water, circling, swimming alone, or not congregating or grouping around the pond. At this time, microscopic examination of the fry revealed a horseshoe-shaped macronucleus and a round or oval micronucleus within the worm's fins and caudal peduncle. The worm could move in a wiggling motion, and the ring-shaped structure rotated like a wheel, confirming it as *Trichodina*. *Trichodina* can be controlled by spraying 0.5 ppm of a solution (mannidamine, plant extract) for 30 minutes, repeating for 2-3 consecutive days. Then, disinfect by spraying 0.5 ppm of chlorine dioxide for 1 hour, changing the water, repeating for 3 consecutive days.

[0109] Example 5: Artificial breeding of Schizothorax fasciatus

[0110] In 2020, the method described in Example 3 was used for the artificial breeding of *Schizothorax fasciatus*. The difference was that during the 2020 rearing process, the fry exhibited sluggishness, swam at the surface, had white cysts on their bodies, and produced large amounts of mucus on their fins and caudal peduncle. The diseased fish tended to gather at the water inlet and push against the water, indicating the presence of *Ichthyophthirius multifiliis* (white spot disease). The following method was used to control *Ichthyophthirius multifiliis*: 210g of chili powder and 100g of dried ginger slices were decocted into a 25kg solution and sprayed throughout the pond once daily for 3-5 consecutive days. Then, 0.5ppm chlorine dioxide was sprayed, soaked for 1 hour, and the water was changed. This process was repeated for 3 consecutive days.

[0111] The breeding method described in this application can improve the spawning rate, fertilization rate, and hatching rate of Schizothorax fasciatus. Through years of trials, it has been shown that the spawning rate of Schizothorax fasciatus obtained by the method described in this application is 70-100%, the fertilization rate is 65-95%, and the hatching rate is 52-75%.

[0112] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0113] The above provides a detailed description of a method for breeding Schizothorax fasciatus according to the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for breeding Schizothorax fasciatus, characterized in that, Includes the following steps: Wild-type F1 maturation and breeding; Breeding broodstock are selected from wild-caught first-generation broodstock after maturation and cultivation, and then subjected to intensive broodstock cultivation. At the same time, water flow stimulation is applied to promote gonadal development. Pumps are installed at the diagonal corners of a square pond to control the water flow rate in the square pond. The water flow control for the intensive broodstock cultivation includes the following steps: in mid-April, the water flow rate is controlled at 0.05-0.1 m / s; in May-June, the water flow rate is controlled at 0.1-0.3 m / s; in July-August, the water flow rate is controlled at 0.3-0.8 m / s; and in September, the water flow rate is controlled at 0.8-2 m / s. Screening for broodstock of the schizothorax fish; Reduce the amount of feed and increase the flow rate of the water before inducing spawning; Inducing spawning involves injecting spawning stimulants into broodstock of the Schizothorax bream and then artificially inseminating them to obtain fertilized eggs. The fertilized eggs obtained after hatching; After hatching, the fry are raised in fertilized water.

2. The method for breeding Schizothorax fasciatus according to claim 1, characterized in that, The culture water used for the maturation and cultivation of the first generation of wild offspring has the following characteristics: water temperature of 15.0~18.0℃, pH of 7.9~8.5, and dissolved oxygen content of 9.1~10.5mg / L. And / or, The wild-type progeny maturation and cultivation includes feeding a first feed, the protein content of which is 35-37%.

3. The method for breeding Schizothorax fasciatus according to claim 1, characterized in that, During the broodstock fortification process, a second feed is provided, wherein the protein content of the second feed is not less than 38%; and / or, The second feed should be given at least twice a day, with each feeding amount being 1% to 2% of the broodstock's body weight.

4. The method for breeding Schizothorax fasciatus according to claim 1, characterized in that, The parental screening includes: Female fish selection criteria: Female fish must be mature individuals aged 5 years or older, with a weight range of 2.5~3.5kg and a body length range of 45~60cm; Male fish selection: Male fish must be individuals aged 3 years or older, with a weight range of 1.2~1.8kg and a body length range of 35~45cm.

5. The method for breeding Schizothorax fasciatus according to claim 4, characterized in that, The oxytocin includes oxytocin, luteinizing hormone-releasing hormone A2, and domperidone; and / or, The spawning-inducing agent injection for the female fish includes a first injection and a second injection. The first injection accounts for one-third of the total spawning-inducing agent injection, and the second injection accounts for two-thirds of the total spawning-inducing agent injection. The interval between the two injections is 15-20 hours, and the spawning effect lasts for 20-26 hours. The dosage of the spawning-inducing agent is: 1200-1500 IU / kg of estradiol, 28-12 μg / kg of luteinizing hormone-releasing hormone A, and 5-9 mg / kg of domperidone. The injection dosage of oxytocin for the male fish was: 600-750 IU / kg of estradiol, 24-6 μg / kg of luteinizing hormone-releasing hormone A, and 2.5-4.5 mg / kg of domperidone.

6. The method for breeding Schizothorax fasciatus according to claim 1, characterized in that, The incubation process includes: micro-flow incubation at a rate of 0.15~0.25 m / s, followed by membrane removal before the seedlings begin to emerge from the membrane, while simultaneously reducing the amount of water entering the incubation process.

7. The method for breeding Schizothorax fasciatus according to claim 1, characterized in that, The cultivation includes fry cultivation, which includes: preparing pond fertilized water, fry fertilized water cultivation, and fry clear water cultivation.

8. The method for breeding Schizothorax fasciatus according to claim 7, characterized in that, The pond fertilization process includes: fermenting the bio-fertilizer and then evenly sprinkling it on the bottom of the feed cultivation pond, controlling the water level at 40-50cm, observing the changes in the pond water color and making adjustments, gradually deepening the pond water level and controlling the water body at 80-100cm. The seedling fertilization and water cultivation includes: removing predatory organisms by netting; releasing the fry into the pond when the live food in the rearing pond reaches its peak after the fry have been swimming horizontally for 2-3 days; adding fresh water to the pond to adjust the temperature difference between the pond water and the temporary holding water; feeding the fry with soybean milk and yeast twice a day; and feeding the fry for the first time after 10-15 days when the live food decreases, continuing this feeding for 50-60 days. The seedling cultivation in clear water includes: when the fry reach an average total length of 2.3-3.5cm in fertile water, they are transferred to a second feeding. After the fry are successfully transferred to a feeding, they are transferred to a clear water pond by netting. During the transfer, the fry are disinfected by soaking in 3-5% sea salt solution for 5-10 minutes before being placed in the clear water pond.

9. The method for breeding Schizothorax fasciatus according to claim 1, characterized in that, This includes disease prevention and control, specifically the prevention and control of water mold, wheelworm, and melon worm.

10. The method for breeding Schizothorax fasciatus according to claim 3, characterized in that, The water flow velocity should be controlled at 0.3-0.8 m / s in the early stage of labor induction and at 0.8-2 m / s during the labor induction period.

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