A full artificial breeding method for first generation of schizothorax lassulus

Abstract

The application provides a kind of Larss naked schizothoracine fish seed one generation full artificial breeding method, A, greenhouse greenhouse is continuously micro water cultivation, hatching brine shrimp as the opening bait of fry, start to increase microparticle feed on the 15th day, all transition to microparticle feed on the 30-40th day;B, every year in December, select 3 years old or more male fish and 4 years old or more female fish into parent fish pool and cultivate for 4 months, feed with fortified feed, increase fresh or ice fresh bait feeding 30 days before breeding;Every year from December to January, the water temperature of aquaculture slowly drops to 8-10℃, slowly rises to 16℃ in February every year, and maintains constant temperature, increases local water flow stimulation in parent fish pool 15-20 days before breeding;C, select LRH-A2 and pituitary combined injection;After injection, parent fish is placed in parent fish pool, water temperature is 14-16℃, and local water flow stimulation;D, fertilized eggs are hatched in flowing water hatching tank, and the hatching time is about 8-12 days.

Description

Technical Field

[0001] This invention belongs to the field of fish farming technology, and specifically relates to a fully artificial breeding method for the first generation of Lhasa naked bream roe. Background Technology

[0002] Currently, my country has relatively mature artificial breeding technology for various freshwater economic fish species (such as carp, grass carp, crucian carp, and silver carp). The main process includes: raising first-generation broodstock, artificial spawning induction, insemination, hatching, and fry rearing. Common techniques include: controlling water temperature (18-24℃), injecting exogenous hormones (such as LRH-A, HCG, PG, etc.), providing artificial nests, and flowing water hatching.

[0003] For plateau schizothorax fish, such as the Lhasa naked schizothorax ( Schizopygopsis younghusbandi The Lhasa naked carp (Sclerotium lataniae) is naturally distributed in the Yarlung Tsangpo River basin at altitudes above 2700 meters. It is characterized by slow growth, late sexual maturity, sensitivity to environmental stress, and low breeding water temperatures (6-16℃). Currently, research on its fully artificial reproduction is almost nonexistent, with only sporadic reports of wild broodstock spawning naturally (or being induced to spawn) after capture. A stable fully artificial reproduction technology system has not yet been established. Existing fully artificial reproduction techniques for fish are mostly based on warm-water or eurythermal fish; directly applying them to the Lhasa naked carp can lead to strong stress responses, poor feeding, and even stunted or degenerated gonadal development in the broodstock.

[0004] CN115633655A discloses a fully artificial breeding method for Lhasa naked bream, but the Lhasa naked bream fry generation has strict requirements for feed, water temperature, water flow and dissolved oxygen. This method lacks water temperature control before the fry parents are bred and adopts constant water temperature cultivation, which is not conducive to the gonadal maturation of plateau fish. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a fully artificial breeding method for Lhasa naked bream roe, enabling large-scale aquaculture production of Lhasa naked bream from broodstock rearing to reproduction.

[0006] The technical solution adopted in this invention is: A method for the artificial breeding of Lhasa naked-bottomed fish, characterized by the following steps: A. F1 generation parent fish breeding The fish are continuously cultured in a micro-flowing water system in the greenhouse. Artemia are hatched and used as the first food for the fry. Microparticle feed is added starting from the 15th day of feeding, and the entire fry are switched to microparticle feed from the 30th to the 40th day. The fry are raised in parallel tanks with a water temperature of 10-14℃ for fry under 3 months old, and in cement ponds with a water temperature of 12-16℃ for fry over 3 months old. B. Broodstock rearing before breeding Every December, select male fish over 3 years old and female fish over 4 years old to be transferred to the broodstock pond for 4 months of rearing. Feed them with fortified feed. Lhasa naked bream is omnivorous with a preference for carnivorous food, and its feeding rate is low at low temperatures. It needs high nutrient density feed supplemented with live food (frozen food) to induce feeding. 30 days before breeding, increase the feeding of live or frozen food 1-2 times a week, each time accounting for 30% of the daily feed amount. From December to January of the following year, the water temperature is slowly lowered to 8-10℃. In February of each year, the water temperature is slowly raised from 8-10℃ to 16℃ and maintained at a constant temperature. 15-20 days before breeding, local water flow stimulation is increased in the broodstock pond. C. Artificial induction of labor LRH-A2 was administered in combination with pituitary injection. The dosage for female fish was 8 μg / kg LRH-A2 + 6 mg / kg pituitary, while the dosage for male fish was halved. After injection, the broodstock were placed in a broodstock pond at a water temperature of 14-16℃ with local water flow stimulation. Eggs and sperm were collected 48 hours after injection and dry insemination was performed. Under normal conditions of higher water temperatures, the spawning-inducing effect in fish typically lasts 8-24 hours, while the effect in Lhasa naked wrasse lasts even longer, up to 48 hours.

[0007] D. Incubation Fertilized eggs are incubated in a flowing water incubator at a water temperature of 12-16℃ and dissolved oxygen ≥7mg / L. Moldy eggs are removed promptly. The incubation period is about 8-12 days. After hatching, the fry continue to be raised in the original tank for another 8-12 days. Once the yolk sac is absorbed, they are fed with newly hatched brine shrimp.

[0008] The incubation water temperature needs to be precisely controlled between 12-16℃. Temperatures above 16℃ will lead to an increase in the rate of deformities, while temperatures below 12℃ will prolong the incubation period and increase the rate of mold growth.

[0009] The water exchange rate in the parallel tanks described in this invention is 3-5 times / hour, the water exchange rate in the cement tanks is 1-2 times / hour, the water exchange rate in the broodstock tanks is 1-2 times / hour, and the water exchange rate in the hatching tanks is 3-5 times / hour.

[0010] The broodstock pond of this invention includes a flow pool and a return water pipe. An inlet pipe is provided above one end of the flow pool, and a vertical partition is provided at the other end. A guide port is provided at the bottom of the partition, and a mesh screen is provided at the guide port. A water level control plate is provided between the partition and the pool wall at the outlet end. A drain outlet is provided at the bottom between the water level control plate and the pool wall at the outlet end. A water pump is connected to the inlet end of the return water pipe. The water pump is located between the water level control plate and the partition. The outlet of the return water pipe is located at the bottom of the inlet end of the flow pool, and the outlet direction is consistent with the water flow direction.

[0011] Preferably, the distance between the pump and the bottom of the pool is 20-30cm to prevent sewage from the bottom of the pool from being carried into the pump.

[0012] Preferably, the water flow pool has a micro-flow of 0.05-0.10 m / s, and the water flow velocity at a distance of 1 m from the outlet of the return water pipe is 0.3-0.4 m / s.

[0013] Parent fish like to gather at a distance of 1 meter from the outlet of the return water pipe. The stimulation of water flow promotes the survival and reproductive performance of parent fish.

[0014] More preferably, the diameter of the return water pipe is 6-8cm, the flow rate is 50-70m³ / h, the length-to-width ratio of the water tank is 4-5:1, and the area is 15-30㎡.

[0015] The length-to-width ratio of the flow tank should be 4-5:1, as this ratio ensures the most efficient water exchange. The area should ideally be 15-30㎡. If the area is too small, the activity of the parent fish will be restricted, and the stress response will be strong. The still water area of ​​the micro-flow will be small, and the fish will not spawn, affecting the spawning induction effect. If the area is too large, it will be inconvenient to check and operate, and the local water flow coverage will be limited, resulting in a lower effective ratio.

[0016] In step B of this invention, from December to January of the following year, the aquaculture water temperature is slowly reduced to 8-10℃ at a rate of 1-2℃ / day. Starting from February of each year, the water temperature is slowly increased from 8-10℃ to 16℃ at a rate of 0.1-0.2℃ / day and maintained at a constant temperature.

[0017] The fortified feed described in this invention is a basic feed containing 42%-45% crude protein and 8%-10% crude fat, with the following added per kilogram of the basic feed: Vitamin E 300mg Vitamin C 500mg DHA / EPA microalgae oil 10g L-carnitine 200mg.

[0018] Compared to omnivorous or herbivorous fish such as carp and grass carp, the Lhasa naked carp is omnivorous with a preference for carnivorous diets. It has a high requirement for n-3 fatty acids and vitamin E, and its feeding rate is low during low-temperature periods. Therefore, it requires a high nutrient density feed supplemented with live bait (frozen bait) to encourage feeding. While conventional fish require 100-150 mg, the Lhasa naked carp requires up to 300 mg. DHA / EPA microalgae oil provides n-3 polyunsaturated fatty acids, and L-carnitine promotes fat metabolism. The addition of additives can promote gonadal development in broodstock and improve egg and sperm quality.

[0019] Preferably, the daily feeding amount of the fortified feed is 1.5%-2.0% of the fish's body weight, because metabolism is slower at low temperatures, which is lower than the feeding amount of conventional fish.

[0020] In step C, the female fish receives two injections into its thoracic cavity. The first injection is 30% of the total dose, and the second injection is given 24 hours later, with the dose being 70% of the total dose. The male fish receives its second injection at the same time as the female fish.

[0021] The beneficial effects of this invention are as follows: 1. The first-generation breeding of Lhasa naked carp requires stringent conditions regarding feed, water temperature, water flow, and dissolved oxygen. This invention uses broodstock that have reached sexual maturity for the first time under artificial breeding conditions as breeding stock, achieving fully artificial breeding of Lhasa naked carp, which can be used for large-scale aquaculture production. 2. This invention employs a slow temperature increase and flow rate control technology before breeding, raising the temperature from 8-10℃ to 16℃ at a rate of 0.1-0.2℃ per day. Combined with a broodstock pond equipped with a return water pipe, this simulates the seasonal temperature changes of the Yarlung Tsangpo River and the stimulation pattern of spring flood flow, inducing gonadal maturation through long-term low-temperature accumulation.

[0022] 3. The broodstock pond is designed with a localized water flow stimulation mode. Water flow stimulation is beneficial to promoting gonadal development. Unlike other fish, the Lhasa naked bream prefers to spawn in still water areas with slight water flow. Furthermore, fish exposed to water flow for a long time will consume a lot of energy. The localized water flow mode of this invention can simultaneously satisfy water flow stimulation and still water environment. The water environment is more in line with the living habits of the Lhasa naked bream in the Tibetan Plateau region than simply increasing the water flow rate.

[0023] 4. This invention adopts a phased regulation strategy of feeding fortified feed 120 days before breeding and feeding live bait 30 days before breeding. It strengthens the essential fatty acids (such as DHA and EPA) and vitamin E for the gonadal maturation of Lhasa naked carp, thereby promoting the reproductive capacity and spawning quality of the parent fish.

[0024] 5. The invention addresses the low-temperature spawning and hatching environment of Lhasa naked bream, optimizes the types of spawning induced agents, and controls the dosage and injection method, thereby increasing the spawning rate of artificially bred Lhasa naked bream from the original 10% to 30% to 94.44%, reducing the mortality rate of spawning broodstock from 50% to less than 5%, achieving a fertilization rate of 94.78% and a hatching rate of 91.07%. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the parent fish pool of the present invention.

[0026] Figure 2 To investigate the effects of different temperature treatments on the growth performance and serum hormone levels of *Lhasa naked carp*.

[0027] (A) Body weight; (B) Body length; (C) Ovarian weight; (D) Serum estradiol (E2) concentration; (E) Serum testosterone (T) concentration; (F) Serum prolactin (PRL) concentration; (G) Serum insulin-like growth factor-1 (IGF-1) concentration. One-way ANOVA was used for statistical analysis. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.

[0028] Figure 3 Histological observation of the ovaries of the Lhasa naked schizothorax at different temperatures.

[0029] H&E staining of ovarian sections. The letters next to “▲”, “#”, “*”, “↑”, and “+” represent primary oocytes, cortical alveolar oocytes, vitelline oocytes, mature oocytes, and atretic oocytes, respectively; (B) Percentage of oocytes at each stage in different temperature groups; (C) Ovarian ROS staining; (D) Ovarian ROS fluorescence intensity; Statistical analysis was performed using one-way ANOVA, *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001.

[0030] Figure 4 The levels of ovarian hormones in the Lhasa naked wrasse at different temperatures.

[0031] (A) Ovarian estradiol (E2) concentration; (B) Ovarian testosterone (T) concentration; (C) Ovarian insulin-like growth factor-1 (IGF-1) concentration; (D) Ovarian prolactin (PRL) concentration; (E) Ovarian growth hormone (GH) concentration; (F) Ovarian luteinizing hormone (LH) concentration; (G) Ovarian progesterone (PRG) concentration; (H) Ovarian follicle-stimulating hormone (FSH) concentration. Statistical analysis was performed using one-way ANOVA. P <0.05, P<0.01, P<0.001, P<0.0001.

[0032] Attached reference numerals: 1. Water tank; 2. Return water pipe; 3. Baffle plate; 4. Water level control plate; 5. Water pump; 6. Inlet pipe; 7. Drain outlet; 8. Guide outlet; 9. Mesh screen; 10. Drain pipe; 21. Outlet. Detailed Implementation

[0033] To more clearly and in detail illustrate the objective and technical solution of this invention, the invention will be further described below through relevant embodiments. These embodiments are merely illustrative of the implementation methods of this invention and do not limit the scope of protection of this invention.

[0034] Culture temperature experiment 1. Experimental Design: The experiment was launched in December 2024, using the same batch of first-generation Lhasa naked carp bred in March 2021 as the experimental subjects. Three temperature treatment groups were set up at the Tibet Autonomous Region Important Endemic Fish Germplasm Resource Farm: ① Constant temperature 12℃ group; ② Constant temperature 16℃ group; ③ Variable temperature group (from December, the temperature was lowered to 8-10℃ at 1-2℃ / day, maintained until February 2025, and then slowly raised to 16℃ at 0.1-0.2℃ / day and maintained at a constant temperature). Each group had 3 replicates, and 90 fish were stocked in each replicate (female:male = 2:1, i.e., 60 females and 30 males).

[0035] 2. Sampling and Reproductive Performance Testing: In March 2025, 30 female fish were randomly selected from each replicate (if the total number of female fish in the replicate was less than 60, half of the total number was selected). After weighing, the ovaries were dissected to determine relative and absolute fertility. The remaining experimental fish were artificially induced to spawn, and the survival rate, egg production (number of eggs), fertilization rate, and hatching rate of the induced broodstock were recorded.

[0036] 3. Aquaculture management: The experiment was conducted in a flowing water tank with dimensions of 10 m × 2 m × 0.6 m (length × width × depth), a flow velocity of 0.05–0.1 m / s, dissolved oxygen ≥ 6 mg / L, ammonia nitrogen ≤ 0.1 mg / L, nitrite nitrogen ≤ 0.05 mg / L, and a photoperiod of 12 L: 12 D.

[0037] 4. Calculation Method Induced spawning rate (%) = (Number of spawning females / Total number of induced spawning females) × 100% Mortality rate of broodstock after induced spawning (%) = Number of broodstock surviving 15 days after induced spawning / Total number × 100% Relative fertility (eggs / g body weight) = Number of eggs laid by the female (eggs) / Female body weight (g) Absolute fertility (eggs / g body weight) = number of eggs laid by the female fish (eggs) Fertilization rate (%) = (Number of viable oocytes in mid-gastrulation / Total number of oocytes) × 100% Hatching rate (%) = Number of hatchlings / Number of fertilized eggs × 100% Deformity rate of hatched fish fry (%) = Number of deformed fry / Total number of fry × 100% Average hatching rate (tails) = Total number of hatched fry / Number of parent fish (females) The results showed that the spawning rate, relative fertility, egg production, and average hatching rate were significantly increased in the variable temperature group.

[0038] Table 1. Results of spawning induction under different broodstock rearing water temperatures.

[0039] Experimental study on the optimal water temperature for raising Lhasa naked-bottomed fish roe based on growth and gonadal development: Experimental Design: This invention utilizes *Schizothorax nakederi* (standard body length 21.5–25 cm, body weight 80–110 g), artificially bred and provided by the Fisheries Research Institute of the Tibet Academy of Agricultural and Animal Husbandry Sciences, and raised in a freshwater fish recirculating aquaculture system from November to December. Before the experiment, *Schizothorax nakederi* was temporarily acclimatized at 12 ℃ for two weeks, based on its optimal growth temperature. Subsequently, the experimental fish were randomly divided into four temperature treatment groups, with three replicates per group and 30 fish per replicate (n=30). They were subjected to chronic stress for 60 days at water temperatures of 12 ℃ (control group), 16 ℃, 20 ℃, and 22 ℃, respectively. After the stress period, the experimental fish were deeply anesthetized and euthanized using MS-222. Their body length and weight were measured individually, and the ovaries were dissected and weighed. Blood was collected from the tail vein, and serum was separated to detect levels of testosterone (T), insulin-like growth factor-1 (IGF-1), estradiol (E2), and prolactin (PRL). A portion of ovarian tissue was homogenized, and the levels of estradiol (E2), growth hormone (GH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were detected. Separately, ovarian tissue was fixed and sectioned, and subjected to hematoxylin-eosin (H&E) staining and reactive oxygen species (ROS) fluorescence staining to observe morphological changes and oxidative stress levels in the ovarian tissue.

[0040] Experimental results: The optimal water temperature for broodstock rearing of Lhasa naked bream is 16℃: at this temperature, ovarian weight increases ( Figure 2 Serum testosterone (T) and IGF-1 levels increased. When the water temperature rose to 20℃, serum estradiol (E2), IGF-1, prolactin (PRL), and E2, GH, LH, and FSH in ovarian tissue all decreased significantly. Figure 2 , Figure 4 The number of primordial follicles decreases, the number of atretic follicles increases, and the function of the HPG axis is suppressed. Figure 3 When the water temperature reaches 22℃, the aforementioned hormones drop to their lowest levels, mature follicles accumulate excessively and atretic follicles increase significantly, and ovarian ROS levels rise sharply, indicating that high temperature has triggered systemic oxidative damage and ovarian degeneration. Figures 2-4 In summary, water temperatures exceeding 16℃ inhibit gonadal development, while temperatures above 20℃ lead to substantial ovarian degeneration. 16℃ is the optimal water temperature for broodstock rearing before breeding.

[0041] A method for fully artificially breeding Lhasa naked-bottomed cichlid roe includes the following steps: A. F1 generation parent fish breeding The fish are continuously cultured in a micro-flowing water system in the greenhouse. Artemia are hatched and used as the first food for the fry. Microparticle feed is added starting from the 15th day of feeding, and the entire fry are switched to microparticle feed from the 30th to the 40th day. The fry are raised in parallel tanks with a water temperature of 10-14℃ for fry under 3 months old, and in cement ponds with a water temperature of 12-16℃ for fry over 3 months old. B. Broodstock rearing before breeding In December, select male fish over 3 years old and female fish over 4 years old and transfer them to the parent fish pond for 4 months of breeding. Feed them with fortified feed. 30 days before breeding, increase the feeding with fresh or frozen food 1-2 times a week, each time accounting for 30% of the daily feed amount. From December to January of the following year, the water temperature is slowly reduced to 8-10℃. In February, starting from the water temperature of 8-10℃, the temperature is slowly increased to 16℃ and maintained at a constant temperature. C. Artificial induction of labor LRH-A2 was administered in combination with the pituitary gland. The dosage for female fish was 8 μg / kg LRH-A2 + 6 mg / kg pituitary gland, while the dosage for male fish was halved. After injection, the broodstock were placed in a broodstock pond at a water temperature of 14-16℃. Eggs and sperm were collected 48 hours after injection, and dry fertilization was performed. D. Incubation Fertilized eggs are incubated in a flowing water incubator at a water temperature of 12-16℃ and dissolved oxygen ≥7 mg / L. Moldy eggs are removed promptly. The incubation period is about 8-12 days. After hatching, the fry continue to be raised in the original tank for another 8-12 days. Once the yolk sac is absorbed, the fry are fed with newly hatched brine shrimp.

[0042] This invention, following the aforementioned breeding method, conducted a breeding experiment in Lhasa, Tibet. Ninety mature males and 90 mature females were selected as Group I (3 replicates per group, 30 males and 30 females per replicate). They were raised in conventional flowing water ponds as broodstock for four months before induced spawning and hatching, with a constant micro-flow of 0.05-0.10 m / s throughout the process. Ninety mature males and 90 mature females were selected as Group II (3 replicates per group, 30 males and 30 females per replicate). They were also raised in conventional flowing water ponds with a constant micro-flow. Twenty days before breeding and after induced spawning, the water flow rate was increased to 0.3-0.4 m / s to achieve flow stimulation. Another ninety mature males and 90 mature females were selected as Group III (3 replicates per group, 30 males and 30 females per replicate). The present invention was then used... Figure 1 The broodstock pond used a micro-flow culture method. Local water flow stimulation was applied 20 days before breeding and after spawning induction injection, with a water flow velocity of 0.3-0.4 m / s at 1m from the outlet of the return water pipe. The experimental results are shown in Table 2. The average spawning rate in the local flow group was higher than that in the micro-flow and regular flow groups.

[0043] Table 2 Results of labor induction experiments with different water flow patterns

[0044] The results showed that the reproductive capacity, egg production, hatching rate, hatching rate, larval emergence rate, and malformation rate of group III, which was stimulated by local water flow, were all superior to the other two groups.

[0045] The fish breeding pond of the present invention includes a flow pool 1 and a return water pipe 2. A water inlet pipe 6 is provided above one end of the flow pool 1, and a vertical partition 3 is provided at the other end. A guide port 8 is provided at the bottom of the partition 3, and a mesh screen 9 is provided at the guide port 8. A water level control plate 4 is provided between the partition 3 and the pool wall at the outlet end. A drain outlet 7 is provided at the bottom between the water level control plate 4 and the pool wall at the outlet end. A water pump 5 is connected to the water inlet end of the return water pipe 2. The water pump 5 is located between the water level control plate 4 and the partition 3. The water outlet 21 of the return water pipe 2 is located at the bottom of the water inlet end of the flow pool 1, and the water outlet direction is consistent with the water flow direction.

[0046] The inlet pipe 6 is positioned above the flow tank 1 for easy observation and control of the water flow rate. The outlet 7 is located at the bottom for easy removal of waste from the bottom of the tank. The height of the water level control plate 4 indicates the water level. The water pump 5 is isolated from the aquaculture water body by a partition 3 to prevent pump vibration from affecting the fish. Water is pumped from the outlet and circulated back to the inlet, exiting from the bottom of the tank, forming a continuous localized small water flow within a certain range. Lhasa naked-bottomed fish will gather near this water flow, stimulating gonad maturation and increasing spawning. The small water flow outside the return flow is a still water area, which is conducive to spawning of Lhasa naked-bottomed fish.

[0047] The water pump should be 20-30cm away from the bottom of the pool to prevent sewage from the bottom of the pool from being carried into the pump.

[0048] The return water pipe has a diameter of 6-8cm and a flow rate of 50-70m³ / h. The length-to-width ratio of the flow pool is 4-5:1, and the area is 15-30㎡. The water flow velocity at 1m from the outlet of the return water pipe is 0.3-0.4 m / s.

[0049] The fortified feed described in this invention is a basic feed containing 42%-45% crude protein and 8%-10% crude fat, with the following added per kilogram of the basic feed: Vitamin E 300mg Vitamin C 500mg DHA / EPA microalgae oil 10g L-carnitine 200mg.

[0050] The daily feeding amount of fortified feed is 1.5%-2.0% of the fish's body weight, which is lower than the feeding amount of conventional fish feed because metabolism is slower at low temperatures.

[0051] In step C of this invention, the female fish receives two injections into its thoracic cavity. The first injection is 30% of the total dose, and the second injection is given 24 hours later, with the dose being 70% of the total dose. The male fish receives its second injection at the same time as the female fish.

[0052] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for fully artificially breeding Lhasa naked-bottomed fish roe, characterized in that, Includes the following steps: A. F1 generation parent fish breeding The fish are continuously cultured in a micro-flowing water system in the greenhouse. Artemia are hatched and used as the first food for the fry. Microparticle feed is added starting from the 15th day of feeding, and the entire fry are switched to microparticle feed from the 30th to the 40th day. The fry are raised in parallel tanks with a water temperature of 10-14℃ for fry under 3 months old, and in cement ponds with a water temperature of 12-16℃ for fry over 3 months old. B. Broodstock rearing before breeding Every December, select male fish over 3 years old and female fish over 4 years old and transfer them to the parent fish pond for 4 months of breeding. Feed them with fortified feed. 30 days before breeding, increase the feeding of fresh or frozen food 1-2 times a week, each time accounting for 30% of the daily feed amount. From December to January of the following year, the water temperature is slowly reduced to 8-10℃. In February of each year, the water temperature is slowly increased from 8-10℃ to 16℃ and maintained at a constant temperature. 15-20 days before breeding, local water flow stimulation is increased in the parent fish pond. C. Artificial induction of labor LRH-A2 was administered in combination with pituitary injection. The dosage for female fish was 8 μg / kg LRH-A2 + 6 mg / kg pituitary, while the dosage for male fish was halved. After injection, the broodstock were placed in a broodstock pond with a water temperature of 14-16℃ and local water flow stimulation. Eggs and sperm were collected 48 hours after injection and dry insemination was performed. D. Incubation Fertilized eggs are incubated in a flowing water incubator at a water temperature of 12-16℃ and dissolved oxygen ≥7 mg / L. Moldy eggs are removed promptly. The incubation period is about 8-12 days. After hatching, the fry continue to be raised in the original tank for another 8-12 days. Once the yolk sac is absorbed, the fry are fed with newly hatched brine shrimp.

2. The method for fully artificially breeding Lhasa naked-bottomed cichlid roe according to claim 1, characterized in that, The water exchange rate in the parallel tank is 3-5 times / hour, the water exchange rate in the cement tank is 1-2 times / hour, the water exchange rate in the broodstock tank is 1-2 times / hour, and the water exchange rate in the hatching tank is 3-5 times / hour.

3. The method for fully artificially breeding Lhasa naked-bottomed cichlid roe according to claim 1, characterized in that, The broodstock pond includes a flow pool and a return water pipe. An inlet pipe is installed above one end of the flow pool, and a vertical partition is installed at the other end. A guide port with a mesh screen is installed at the bottom of the partition. A water level control plate is installed between the partition and the pool wall at the outlet end. A drain outlet is installed at the bottom between the water level control plate and the pool wall at the outlet end. A water pump is connected to the inlet end of the return water pipe. The water pump is located between the water level control plate and the partition. The outlet of the return water pipe is located at the bottom of the inlet end of the flow pool, and the outlet direction is consistent with the water flow direction.

4. The method for fully artificially breeding Lhasa naked-bottomed fish roe according to claim 3, characterized in that, The distance between the water pump and the bottom of the pool is 20-30cm.

5. The method for fully artificially breeding Lhasa naked-bottomed fish roe according to claim 3, characterized in that, The water flow pool has a micro-flow of 0.05-0.10 m / s, and the water flow velocity at a distance of 1 m from the outlet of the return water pipe is 0.3-0.4 m / s.

6. The method for fully artificially breeding Lhasa naked-bottomed fish roe according to claim 5, characterized in that, The return water pipe has a diameter of 6-8cm and a flow rate of 50-70m³ / h. The length-to-width ratio of the water tank is 4-5:1, and the area is 15-30㎡.

7. The method for fully artificially breeding Lhasa naked-bottomed fish roe according to claim 1, characterized in that, In step B, from December to January of the following year, the aquaculture water temperature is slowly reduced to 8-10℃ at a rate of 1-2℃ / day. Starting in February of each year, the water temperature is slowly increased from 8-10℃ to 16℃ at a rate of 0.1-0.2℃ / day and maintained at a constant temperature.

8. The method for fully artificially breeding Lhasa naked-bottomed cichlid roe according to claim 1, characterized in that, The fortified feed is a basic feed containing 42%-45% crude protein and 8%-10% crude fat, with the following added per kilogram of the basic feed: Vitamin E 300mg Vitamin C 500mg 10g DHA / EPA microalgae oil L-carnitine 200mg.

9. The method for fully artificially breeding Lhasa naked-bottomed fish roe according to claim 8, characterized in that, The daily feeding amount of fortified feed is 1.5%-2.0% of the fish's body weight.

10. The method for fully artificially breeding Lhasa naked-bottomed fish roe according to claim 1, characterized in that, In step C, the female fish receives two injections into its thoracic cavity. The first injection is 30% of the total dose, and the second injection is given 24 hours later, with the dose being 70% of the total dose. The male fish receives its second injection at the same time as the female fish.

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