A method for artificially controlling off-season breeding of mandarin fish

Abstract

The present invention discloses a method for artificially controlling off-season breeding of mandarin fish, which relates to the field of freshwater fish breeding technology. The method comprises the following steps: (1) screening mandarin fish broodstock and transferring them to indoor broodstock cultivation barrels for cultivation; (2) controlling the indoor ambient temperature so that the water temperature in the cultivation barrels for male and female mandarin fish is maintained at 13°C for 6 weeks, and then controlling the water temperature to rise to 23°C within 2 weeks and maintain it for 4 weeks. The present invention promotes the early development and maturation of the male fish's gonads through cooling and heating treatments, and promotes the early development and maturation of the female fish's gonads through cooling and heating treatments and full-process blue LED light source irradiation treatments, allowing subsequent artificial induction of labor and artificial insemination operations. Compared with traditional breeding methods, this method has a higher degree of controllability, better development of the male fish's gonads, and earlier ovulation of the female fish, enabling mandarin fish to be put on the market faster and better supplied to the market that same year, and has extremely high development potential.

Description

Technical Field

[0001] The invention relates to the technical field of freshwater fish breeding, and more particularly to a method for artificially controlling off-season breeding of mandarin fish. Background Art

[0002] The mandarin fish (Siniperca chuatsi Basilewsky), also known as the mandarin fish and sweet-scented fish, is the fastest-growing and largest of the nine known species of fish in the subfamily Siniperinae of the order Perciformes. It feeds on live bait throughout its life. Its tender, delicious meat, lack of intramuscular spines, and high nutritional value make it a popular aquaculture species in my country. Mandarin fish originated as marine fish. In the early 3rd century, the intrusion and retreat of seawater forced them to migrate to freshwater, necessitating distinct seasons for their survival and reproduction. High water temperatures in summer and low water temperatures in winter facilitate the maturation and reproduction of mandarin fish eggs during the warming of the water in late spring and early summer. Furthermore, due to sex differences, the ovarian development of female mandarin fish is asynchronous, requiring light to accumulate nutrients necessary for gonadal development. Under natural conditions, the spawning season for female mandarin fish is from April to September each year. This results in a difficulty meeting market demand due to the spawning season. From June to August each year, the number of mandarin fish on the market is scarce, causing prices to soar. This significantly impacts the development of the mandarin fish industry. Therefore, the development of off-season mandarin fish breeding technology is particularly important.

[0003] In recent years, there have been many studies on the reproduction of mandarin fish and the integration of some process methods for artificial reproduction of mandarin fish, which has increased the yield of mandarin fish seedlings to a certain extent. However, there has been no breakthrough improvement in the off-season breeding methods of mandarin fish, and no guidance has been provided for the design and optimization of breeding conditions in the culture environment.

[0004] Therefore, providing a method for off-season breeding of mandarin fish, increasing the number of mandarin fish seedlings, and achieving faster listing of mandarin fish in the same year and better market supply are problems that need to be urgently solved by the present invention. Summary of the Invention

[0005] The present invention provides a method for artificially controlling off-season breeding of mandarin fish, aiming to solve the problems existing in the above-mentioned background technology.

[0006] In order to achieve the above technical objectives, the present invention mainly adopts the following technical solutions:

[0007] A method for artificially controlling off-season breeding of mandarin fish comprises the following steps:

[0008] (1) selecting mandarin fish broodstock, transferring them to broodstock cultivation tanks, and culturing them in an indoor environment;

[0009] (2) Control the indoor environmental temperature so that the water temperature in the culture tank of male and female mandarin fish is maintained at 13℃ for 6 weeks, and then control the water temperature to rise to 23℃ within 2 weeks and maintain it for 4 weeks to induce female mandarin fish to spawn or male mandarin fish to mature.

[0010] In a preferred embodiment of the present invention, in step (1), the mandarin fish broodstock are temporarily raised in a temporary holding pond, the temporary holding pond and the tools used in mandarin fish breeding are soaked and disinfected with a 3% potassium permanganate solution for 24 hours in advance, the broodstock breeding tank is 2 meters long, 2 meters wide, and 1.6 meters deep, and is equipped with a circulating water system. The breeding water body is circulating water, and the circulating water is supplied by an indoor circulating water culture system.

[0011] Furthermore, step (2) also includes the step of light induction of the female broodstock of mandarin fish throughout the whole process: controlling the light color of the indoor environment, and irradiating the female broodstock of mandarin fish with blue light of a light intensity of 10lx throughout the whole culture process.

[0012] Furthermore, the indoor circulating aquaculture system includes eight parts: breeding equipment, filtering equipment, a water reservoir, a plant purification pool, a microbial treatment pool, a sterilization device, a temperature control device and an LED light source control device. The water in the breeding equipment is filtered by the filtering equipment and enters the water reservoir. Then, the water enters the plant purification pool and the microbial treatment pool in turn for treatment. Finally, the water is sterilized by the sterilization device and then enters the broodstock breeding barrel. The temperature control device controls the indoor circulating water temperature, and the LED light source control device controls the indoor light color and light intensity.

[0013] Furthermore, the temperature control device includes a heating pump and a thermostat, which adjusts the indoor circulating water temperature through the heating pump and uses the thermostat to perform constant temperature control; the LED light source control device includes a blue LED aquaculture lighting lamp and a timer, and the blue LED aquaculture lighting lamp adjusts the light intensity and uses the timer to control the light cycle of the blue light.

[0014] In another preferred embodiment of the present invention, in step (1), male and female mandarin fish parents are selected that are healthy, free of injury or disease, and weigh 600-900 g and are over 2 years old.

[0015] Furthermore, the selected male and female mandarin fish parents need to be soaked and disinfected in 5% sea salt for 20 minutes before being transferred to a parent fish breeding tank equipped with a circulating water system.

[0016] In another preferred embodiment of the present invention, in step (2), the female broodstock of mandarin fish and the male broodstock of mandarin fish are raised separately, and the parent density is 10 kg / m 3During the mid-term intensive cultivation period of broodstock, feed twice a day. According to the feeding habits of mandarin fish, the feeding time is set at 8:00 and 17:00, and feed A is fed at 5% of the parent's body weight. During the intensive cultivation period of broodstock breeding, feed A is replaced with feed B. During the breeding period, clean up the residues and feces in time, observe the feeding situation of the parents, and check the health status regularly under the microscope. When abnormal mandarin fish parents are found, isolate them in time and carry out targeted intensive cultivation.

[0017] Furthermore, the feed A, calculated by mass, includes 15 parts of fermented soybean meal, 5 parts of soybean protein concentrate, 51 parts of fish meal, 8 parts of starch, 10 parts of meat quality improver, 2 parts of multivitamins, 2 parts of multiminerals, 2 parts of attractant, 2 parts of seaweed polysaccharide and 3 parts of yeast powder;

[0018] The feed B is calculated by mass and includes 15 parts of fermented soybean meal, 8 parts of soybean protein concentrate, 41 parts of fish meal, 8 parts of starch, 9 parts of fish oil, 13 parts of reproduction enhancer, 2 parts of multivitamins, 2 parts of multiminerals, and 2 parts of seaweed polysaccharides.

[0019] Furthermore, in the feed A, 10 parts of the meat quality improver include the following raw materials in parts by weight: 3 parts of fish oil, 0.5 parts of krill oil, 2 parts of soybean oil, 1 part of linseed oil, 0.5 parts of dried longan powder, 1 part of pig liver powder, 0.8 parts of kelp powder, and 1.2 parts of houttuynia cordata;

[0020] 2 parts of attractants include the following raw materials in parts by weight: 1 part of fish slurry, 0.3 parts of squid paste, 0.3 parts of allicin, and 0.4 parts of brewer's yeast;

[0021] In the feed B, 13 parts of the reproduction enhancer are made from the following raw materials in parts by weight: 1 part of krill oil, 1 part of shrimp meal, 3 parts of oyster powder, 1 part of black wolfberry, 1 part of Ligustrum lucidum, 3 parts of liquorice, 1 part of kelp powder, and 2 parts of houttuynia cordata;

[0022] In the feed A and feed B, the compound vitamins contain vitamin B1, 30 mg; vitamin B2, 60 mg; vitamin B6, 30 mg; vitamin B 12 , 0.22mg; Vitamin D3, 5mg; Vitamin E, 160mg; Vitamin K3, 50mg; Folic acid, 20mg; Biotin, 2.5mg; Calcium pantothenate, 100mg; Vitamin (35%), 250mg; Niacin, 200mg; Rice husk powder, 999mg;

[0023] The composite minerals contain 10 mg of MnSO4, 10 mg of MgSO4, 95 mg of KCl, 165 mg of NaCl, 20 mg of ZnSO4, 1 mg of KI, 12.5 mg of CuSO4, 105 mg of FeSO4, 0.1 mg of Na2SeO3, and 1.5 mg of Co per kilogram of diet.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention uses a temperature control device (heat pump and thermostat) in an indoor recirculating aquaculture system to regulate the water temperature of male mandarin fish broodstock. A series of cooling and heating processes are used to accelerate the development and maturation of the male and female mandarin fish gonads. The temperature control device (heat pump and thermostat) in the indoor recirculating aquaculture system also regulates the water temperature of female mandarin fish broodstock. An LED light source control device (blue LED aquaculture lighting and timer) is used to adjust the light intensity. A series of cooling and heating processes, combined with a timer to control the blue light cycle, accelerate the development and maturation of the female mandarin fish gonads, allowing for subsequent artificial induced fertilization and artificial insemination.

[0026] The present invention lays the foundation for the standardization and industrialization of artificial propagation of mandarin fish, while greatly saving land, manpower and water resources. Moreover, compared with traditional breeding methods, this method is more controllable, the gonadal development of broodstock is better, and the ovulation time is earlier, so that mandarin fish can be put on the market faster in the same year and have better market supply, and has extremely high development potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides a broodstock cultivation barrel for aquaculture facilities;

[0028] Figure 2 The temperature control equipment of the indoor circulating aquaculture system provided by the present invention;

[0029] Figure 3 The present invention provides an indoor LED light source control device and a matching broodstock cultivation barrel;

[0030] Figure 4 The figure shows the changes in the appearance of the gonads of mandarin fish parents at the temperature control part of the present invention at the sampling point on February 10, wherein the constant temperature cultivation conditions are A and D, the rising temperature cultivation conditions are B and E, and the cooling temperature cultivation conditions are C and F;

[0031] Figure 5 The water temperature changes under each condition during the 12-week temperature control test period provided by the present invention, wherein control represents constant temperature cultivation conditions; warming represents warming cultivation conditions; cooling represents cooling cultivation conditions; and the arrows represent the time of spawning.

[0032] Figure 6 Effects of the three temperature control conditions provided by the present invention on the gonadal index (GSI) of female broodstock (A) and male broodstock (B);

[0033] Figure 7 Effects of the three temperature control conditions provided by the present invention on the levels of estradiol (E2) in female fish serum (A) and testosterone (T) in male fish serum (B);

[0034] Figure 8 Representative micrographs (AE, ae) of female ovaries under temperature-controlled cooling conditions provided by the present invention, wherein a and A represent the sampling points on November 18; b and B represent the sampling points on December 9; c and C represent the sampling points on December 30; d and D represent the sampling points on January 20; e and E represent the sampling points on February 10, Pg: primary growth period, Evg: early vitellogenesis, Lvg: late vitellogenesis, Nu: nucleolus, Y: yolk, Od: oil droplet;

[0035] Figure 9 Representative micrographs (AE, ae) of male testicles under temperature-controlled cooling conditions provided by the present invention, wherein a and A represent the sampling points on November 18; b and B represent the sampling points on December 9; c and C represent the sampling points on December 30; d and D represent the sampling points on January 20; e and E represent the sampling points on February 10, Sg: spermatogonia; Sc: spermatocyte; St: spermatid; Sz: sperm.

[0036] Figure 10 The effects of the four light-controlled conditions provided by the present invention on the gonadal index (GSI) of female broodstock;

[0037] Figure 11 The effects of the four light-controlled conditions provided by the present invention on the serum estradiol (E2) level of female fish;

[0038] Figure 12 The effects of the four light-controlled conditions provided by the present invention on the serum melatonin (MT) level of female fish;

[0039] Figure 13 The effects of the four light-controlled conditions provided by the present invention on the serum vitellogenin (VTG) level of female fish;

[0040] Figure 14 The present invention provides the effects of four light-controlled conditions on the superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in the liver of female fish. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] Example 1: Temperature Control During the Off-Season to Induce Gonadal Development in Mandarin Fish Broodstock

[0043] A method for artificially controlling off-season breeding of mandarin fish comprises the following steps:

[0044] (1) Disinfection of temporary holding ponds: Soak the temporary holding ponds and tools used in the breeding process in a 3% potassium permanganate solution for 24 hours for disinfection;

[0045] (2) Preparation of broodstock culture tank: The broodstock culture tank is 2m long, 2m wide and 1.6m deep and is equipped with a circulating water system, such as Figure 1 As shown, the water in the cultivation barrel is circulating water, which is supplied by the indoor circulating water cultivation system, wherein the indoor circulating water cultivation system is composed of cultivation equipment, filtering equipment, water reservoir, plant purification pool, microbial treatment pool, sterilization device, and temperature control equipment. The water in the cultivation equipment is filtered by the filtering equipment and enters the water reservoir. Then, the water reservoir enters the plant purification pool and microbial treatment pool in turn for treatment. Finally, the water is sterilized by the sterilization device and then enters the broodstock cultivation barrel. The temperature control device controls the temperature of the indoor circulating water. Among them, the temperature control device is as follows. Figure 2 As shown, it includes a heating pump and a thermostat, the indoor circulating water temperature is adjusted by the heating pump, and the thermostat is used for constant temperature control;

[0046] (3) Screening broodstock: 40 male and female mandarin fish parents of 2 years old or older, which are healthy, without injury or disease, and weigh 600-900 g, are selected and disinfected by soaking in 5% sea salt for 20 minutes and then transferred to a broodstock cultivation tank in a circulating water system;

[0047] (4) Mandarin fish broodstock breeding: Female mandarin fish broodstock and male mandarin fish broodstock are raised separately, with a broodstock density of 10 kg / m 3 During the intensive culture period of the middle stage of broodstock rearing, feed twice a day. According to the feeding habits of mandarin fish, the feeding time is set at 8:00 and 17:00, and feed A is fed at 5% of the parent's body weight. During the intensive culture period of the broodstock breeding period, feed A is replaced with feed B. During the rearing period, residues and feces are cleaned in time, the feeding situation of the parents is observed, and the health status is checked regularly by microscopic examination. If abnormal mandarin fish parents are found, they will be isolated in time and targeted intensive culture will be carried out.

[0048] Among them, the feed A formula includes the following components in parts by mass: 15 parts of fermented soybean meal, 5 parts of soybean protein concentrate, 51 parts of fish meal, 8 parts of starch, 10 parts of meat quality improver, 2 parts of multivitamins, 2 parts of multiminerals, 2 parts of attractant, 2 parts of seaweed polysaccharide and 3 parts of yeast powder.

[0049] Among them, 10 parts of meat improver are made from the following raw materials in parts by weight: 3 parts of fish oil, 0.5 parts of krill oil, 2 parts of soybean oil, 1 part of linseed oil, 0.5 parts of dried longan powder, 1 part of pork liver powder, 0.8 parts of kelp powder, and 1.2 parts of houttuynia cordata.

[0050] 2 parts of attractants are made from the following raw materials in parts by weight: 1 part of fish slurry, 0.3 parts of squid paste, 0.3 parts of allicin, and 0.4 parts of brewer's yeast.

[0051] The multivitamin contains vitamin B1, 30 mg; vitamin B2, 60 mg; vitamin B6, 30 mg; vitamin B 12 , 0.22mg; Vitamin D3, 5mg; Vitamin E, 160mg; Vitamin K3, 50mg; Folic acid, 20mg; Biotin, 2.5mg; Calcium pantothenate, 100mg; Vitamin (35%), 250mg; Niacin, 200mg; Rice husk powder, 999mg.

[0052] The composite minerals contain 10 mg of MnSO4, 10 mg of MgSO4, 95 mg of KCl, 165 mg of NaCl, 20 mg of ZnSO4, 1 mg of KI, 12.5 mg of CuSO4, 105 mg of FeSO4, 0.1 mg of Na2SeO3, and 1.5 mg of Co per kilogram of diet.

[0053] During the feeding period of feed A, the mandarin fish were dissected after 60 days of feeding, and their muscle and fatty acid composition were analyzed. The results were compared with those of mandarin fish fed with commercial feed, as shown in Table 1 below.

[0054] Table 1 Fatty acid composition of muscle tissue of mandarin fish at 60 days old

[0055]

[0056]

[0057] In Table 1, the control group was ordinary commercial feed, and the treatment group was feed A. It can be seen that the content of polyunsaturated fatty acids in muscle increased significantly, and the content of arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid was significantly higher than that of the control group.

[0058] The optimum water temperature for the reproduction of mandarin fish parents is 23℃~26℃, which is generally in May and June. Intensive culture is implemented in the first three months of the parent breeding season, that is, around February of the same year. This method can significantly improve the reproductive capacity, fertilization rate, hatching rate, fry survival rate and growth performance of mandarin fish. 150 one-year-old mandarin fish parents with strong body shape, no injuries or diseases, and weighing more than 0.4kg were selected from the core population of mandarin fish parents, including 75 males and 75 females. All parents were soaked and disinfected in 5% sea salt for 20 minutes and then transferred to the circulating water system breeding barrel, and males and females were raised separately. The breeding density is 10kg / m 3 The male and female fish were fed with ordinary commercial feed and feed B respectively, and the breeding cycle was three months.

[0059] The feed B formula includes the following components in parts by mass: 15 parts of fermented soybean meal, 8 parts of soybean protein concentrate, 41 parts of fish meal, 8 parts of starch, 9 parts of fish oil, 13 parts of reproduction enhancer, 2 parts of multivitamins, 2 parts of multiminerals, and 2 parts of seaweed polysaccharides.

[0060] Among them, 13 parts of reproduction enhancer are made of the following raw materials in parts by weight: 1 part of krill oil, 1 part of shrimp powder, 3 parts of oyster powder, 1 part of black wolfberry, 1 part of Ligustrum lucidum, 3 parts of licorice, 1 part of kelp powder, and 2 parts of Houttuynia cordata.

[0061] The multivitamin contains 30mg of vitamin B1, 60mg of vitamin B2, 30mg of vitamin B6, and 30mg of vitamin B6 per kilogram of diet. 12 , 0.22mg; Vitamin D3, 5mg; Vitamin E, 160mg; Vitamin K3, 50mg; Folic acid, 20mg; Biotin, 2.5mg; Calcium pantothenate, 100mg; Vitamin (35%), 250mg; Niacin, 200mg; Rice husk powder, 999mg.

[0062] Among them, the composite minerals contain MnSO4, 10 mg; MgSO4, 10 mg; KCl, 95 mg; NaCl, 165 mg; ZnSO4, 20 mg; KI, 1 mg; CuSO4, 12.5 mg; FeSO4, 105 mg; Na2SeO3, 0.1 mg; and Co, 1.5 mg per kilogram of diet.

[0063] After three months of enrichment with high-unsaturated fatty acids, 50 large, reddish anal mandarin fish (Siniperca chuatsi) were selected from an indoor recirculating aquaculture system for induced fertilization injections. The male-to-female ratio was 1:1. A single injection into the pectoral fin axilla contained a mixture of diocreatine (DOM), a luteinizing hormone-releasing hormone analog (LRH-A2), and human chorionic gonadotropin (HCG). Females received 4 mg / kg DOM, 10 μg / kg LRH-A2, and 1100 units / kg HCG, while males received half the dose given to females. Following the injections, all broodstock were transferred to cages set in a 6m x 6m x 1m cement tank, with cages measuring 2m x 1m x 1m. The water temperature was maintained at 25°C. After 30 hours, the mandarin fish spawned naturally and fertilized. Samples were collected and tested for various indices.

[0064] Table 2 Effects of high unsaturated fatty acid diet fortification on growth performance of mandarin fish

[0065]

[0066] Table 2 shows the effects of fortifying mandarin fish with a high-unsaturated fatty acid feed on their growth performance after three months of culture. D1 is a common commercial feed, and D2 is feed B. It can be seen that the weight gain rate and specific growth rate of the parents increased significantly after fortification.

[0067] Table 3 Effects of high unsaturated fatty acid diet fortification on the reproductive performance of mandarin fish

[0068]

[0069] As shown in Table 3, after three months of fortification of mandarin fish parents with high unsaturated fatty acid feed, there was a significant effect on the absolute fecundity, relative fecundity, hatching rate and 3dph fry survival rate of the parents.

[0070] Table 4 Effects of high unsaturated fatty acid diet fortification on the quality of mandarin fish eggs

[0071]

[0072] As shown in Table 4, after three months of culture of mandarin fish parents with high unsaturated fatty acid feed, the egg weight increased significantly; the total length, yolk sac diameter and oil ball diameter of the newly hatched fry all increased.

[0073] Table 5 Effects of high unsaturated fatty acid diet fortification on the fatty acid composition of mandarin fish eggs

[0074]

[0075]

[0076] As shown in Table 5, after three months of fortified culture of mandarin fish parents with high unsaturated fatty acid feed, the ARA, EPA, and DHA contents of mandarin fish eggs increased significantly, and the n-3 polyunsaturated fatty acid content increased significantly.

[0077] Combining the data of the control group and the treatment group in Tables 1 to 5, it can be seen that the fatty acid accumulation and reproductive performance of mandarin fish can be significantly improved by adopting the above feed.

[0078] (5) Cooling treatment cultivation:

[0079] The cooling process started on November 18, 2021, during the off-season for mandarin fish breeding. The water temperature for the female and male mandarin fish broodstock was regulated by the temperature control equipment (heating pump and thermostat) in the indoor circulating aquaculture system to maintain the water temperature at 13°C for 6 weeks. Then, the water temperature was raised to 23°C within 2 weeks through the temperature control equipment of the indoor circulating aquaculture system and maintained for 4 weeks. The temperature change curve is shown in the figure below. Figure 5 shown.

[0080] (6) Sampling

[0081] During the experiment, samples were taken every 3 weeks, with 2-3 females and 2-3 males each time, on November 18, 2021, December 9, 2021, and December 30, 2021, respectively. On January 20, 2022, and February 10, 2022. The fish were randomly captured, anesthetized with MS222, and their body weights were measured. 2-3 mL of blood was collected from the tail vein using a syringe and placed in a refrigerated centrifuge tube, centrifuged at 4000 rpm for 20 minutes. The supernatant was collected and stored at -80 °C, and the estradiol concentration in female fish and the testosterone concentration in male fish were determined using an ELISA kit. Finally, the gonadal tissue was dissected and removed, and the appearance changes were as follows: Figure 4 As shown in the anatomical micrographs Figure 8 、 Figure 9 shown.

[0082] Comparative Example 1

[0083] A method for artificially controlling off-season breeding of mandarin fish comprises the following steps:

[0084] (1) Disinfection of temporary holding ponds: Soak the temporary holding ponds and tools used in the breeding process in a 3% potassium permanganate solution for 24 hours for disinfection;

[0085] (2) Preparation of broodstock cultivation barrel: The broodstock cultivation barrel is 2m long, 2m wide and 1.6m deep, and is equipped with a circulation facility. The water in the cultivation barrel is circulating water, which is supplied by an indoor circulating water aquaculture system. The indoor circulating water aquaculture system consists of seven parts: aquaculture equipment, filtering equipment, a water reservoir, a plant purification pool, a microbial treatment pool, a sterilization device, and a temperature control device. The water in the aquaculture equipment is filtered by the filtering equipment and enters the water reservoir. The water then enters the plant purification pool and the microbial treatment pool for treatment. Finally, the water is sterilized by the sterilization device and then enters the broodstock cultivation barrel. The temperature control device controls the temperature of the indoor circulating water. The temperature control device includes a heating pump and a thermostat. The indoor circulating water temperature is adjusted by the heating pump, and the thermostat is used for constant temperature control.

[0086] (3) Screening broodstock: 40 male and female mandarin fish parents of 2 years old or older, which are healthy, without injury or disease, and weigh 600-900 g, are selected and disinfected by soaking in 5% sea salt for 20 minutes and then transferred to a broodstock cultivation tank in a circulating water system;

[0087] (4) Mandarin fish broodstock breeding: Female mandarin fish broodstock and male mandarin fish broodstock are raised separately, with a broodstock density of 10 kg / m 3 During the intensive culture period of the middle stage of parent fish rearing, the broodstock were fed twice a day. According to the feeding habits of mandarin fish, the feeding time was set at 8:00 and 17:00, and feed A was fed at 5% of the parent fish's body weight. During the intensive culture period of the broodstock breeding period, feed A was replaced with feed B. During the rearing period, residues and feces were cleaned in time, the feeding situation of the parents was observed, and the health status was checked regularly by microscopic examination. If abnormal mandarin fish parents were found, they were isolated in time and intensive cultured in a targeted manner. Feed A or feed B was the same as in Example 1.

[0088] (5) Natural water temperature cultivation:

[0089] The water temperature of the control condition is the water temperature of the mandarin fish breeding off-season without any treatment, which is the natural water temperature of the culture barrel. The temperature change curve is as follows: Figure 5 The remaining conditions are the same as those in Example 1.

[0090] (6) Sampling

[0091] During the experiment, samples were taken every 3 weeks, with 2-3 females and 2-3 males each time, on November 18, 2021, December 9, 2021, and December 30, 2021. On January 20, 2022, and February 10, 2022. Fish were randomly captured, anesthetized with MS222, and their body weights were measured. 2-3 mL of blood was collected from the tail vein using a syringe and placed in a refrigerated centrifuge tube, centrifuged at 4000 rpm for 20 minutes. The supernatant was collected and stored at -80 °C, and the estradiol concentration in female fish and the testosterone concentration in male fish were determined using an ELISA kit. Finally, the gonadal tissue was dissected and removed, as shown in the figure. Figure 4 shown.

[0092] Comparative Example 2

[0093] A method for artificially controlling off-season breeding of mandarin fish comprises the following steps:

[0094] (1) Disinfection of temporary holding ponds: Soak the temporary holding ponds and tools used in the breeding process in a 3% potassium permanganate solution for 24 hours for disinfection;

[0095] (2) Preparation of broodstock cultivation barrel: The broodstock cultivation barrel is 2m long, 2m wide and 1.6m deep, and is equipped with a circulation facility. The water in the cultivation barrel is circulating water, which is supplied by an indoor circulating water aquaculture system. The indoor circulating water aquaculture system consists of seven parts: aquaculture equipment, filtering equipment, a water reservoir, a plant purification pool, a microbial treatment pool, a sterilization device, and a temperature control device. The water in the aquaculture equipment is filtered by the filtering equipment and enters the water reservoir. The water then enters the plant purification pool and the microbial treatment pool for treatment. Finally, the water is sterilized by the sterilization device and then enters the broodstock cultivation barrel. The temperature control device controls the temperature of the indoor circulating water. The temperature control device includes a heating pump and a thermostat. The indoor circulating water temperature is adjusted by the heating pump, and the thermostat is used for constant temperature control.

[0096] (3) Screening broodstock: 40 male and female mandarin fish parents of 2 years old or older, which are healthy, without injury or disease, and weigh 600-900 g, are selected and disinfected by soaking in 5% sea salt for 20 minutes and then transferred to a broodstock cultivation tank in a circulating water system;

[0097] (4) Mandarin fish broodstock breeding: Female mandarin fish broodstock and male mandarin fish broodstock are raised separately, with a broodstock density of 10 kg / m 3During the intensive culture period of the middle stage of parent fish rearing, the broodstock were fed twice a day. According to the feeding habits of mandarin fish, the feeding time was set at 8:00 and 17:00, and feed A was fed at 5% of the parent fish's body weight. During the intensive culture period of the broodstock breeding period, feed A was replaced with feed B. During the rearing period, residues and feces were cleaned in time, the feeding situation of the parents was observed, and the health status was checked regularly by microscopic examination. If abnormal mandarin fish parents were found, they were isolated in time and intensive cultured in a targeted manner. Feed A or feed B was the same as in Example 1.

[0098] (5) Temperature treatment and cultivation:

[0099] The temperature increase started on November 18, 2021, during the off-season for mandarin fish breeding. The water temperature for the female and male mandarin fish broodstock was regulated by the temperature control equipment (heating pump and thermostat) of the indoor recirculating aquaculture system to keep the water temperature at 23°C for 12 weeks. The temperature change curve is shown in the figure below. Figure 5 The remaining conditions are the same as those in Example 1.

[0100] (6) Sampling

[0101] During the experiment, samples were taken every 3 weeks, with 2-3 females and 2-3 males each time, on November 18, 2021, December 9, 2021, and December 30, 2021. On January 20, 2022, and February 10, 2022. Fish were randomly captured, anesthetized with MS222, and their body weights were measured. 2-3 mL of blood was collected from the tail vein using a syringe and placed in a refrigerated centrifuge tube, centrifuged at 4000 rpm for 20 minutes. The supernatant was collected and stored at -80 °C, and the estradiol concentration in female fish and the testosterone concentration in male fish were determined using an ELISA kit. Finally, the gonadal tissue was dissected and removed, as shown in the figure. Figure 4 shown.

[0102] Example 2: Light-controlled induction of gonadal development in female mandarin fish during the off-season

[0103] A method for artificially controlling off-season breeding of mandarin fish comprises the following steps:

[0104] (1) Disinfection of temporary holding ponds: Soak the temporary holding ponds and tools used in the breeding process in a 3% potassium permanganate solution for 24 hours for disinfection;

[0105] (2) Preparation of broodstock cultivation barrel: The broodstock cultivation barrel is 2m long, 2m wide and 1.6m deep, equipped with circulation facilities. The water in the cultivation barrel is circulating water, which is supplied by an indoor circulating water aquaculture system. The indoor circulating water aquaculture system consists of eight parts: aquaculture equipment, filtration equipment, water reservoir, plant purification pool, microbial treatment pool, sterilization device, temperature control equipment, and LED light source control equipment. The water in the aquaculture equipment is filtered by the filtration equipment and enters the water reservoir. The water then enters the plant purification pool and microbial treatment pool for treatment. Finally, the water is sterilized by the sterilization device before entering the broodstock cultivation barrel. The temperature control equipment controls the temperature of the indoor circulating water. The temperature control equipment includes a heating pump and a thermostat. The indoor circulating water temperature is adjusted by the heating pump and the thermostat is used for constant temperature control. The LED light source control equipment controls the indoor light color and light intensity.

[0106] (3) Screening female fish: 40 female mandarin fish parents aged 2 years and above, which are healthy, free of injury or disease, and weigh 600-900 g, are selected and disinfected by soaking in 5% sea salt for 20 minutes and then transferred to a broodstock cultivation tank in a circulating water system;

[0107] (4) Mandarin fish broodstock breeding: The density of female mandarin fish broodstock is 10kg / m 3 During the mid-stage intensive culture period of the female broodstock, the broodstock were fed twice a day. According to the feeding habits of the mandarin fish, the feeding time was set at 8:00 and 17:00. Feed A was fed at 5% of the parent's body weight. During the intensive culture period of the broodstock breeding period, Feed A was replaced with Feed B. During the feeding period, the residues and feces were cleaned in time, the feeding situation of the parents was observed, and the health status was checked regularly by microscopic examination. If abnormal mandarin fish parents were found, they were isolated in time and intensive cultured in a targeted manner. Feed A or Feed B was the same as in Example 1.

[0108] (5) Female fish cooling and blue light treatment cultivation:

[0109] Cooling began on November 18, 2022, during the off-season for female mandarin fish. The water temperature for the female mandarin fish broodstock was maintained at 13°C for six weeks using the temperature control equipment (heat pump and thermostat) in the indoor recirculating aquaculture system. Within two weeks, the water temperature was raised to 23°C using the temperature control equipment in the indoor recirculating aquaculture system and maintained for four weeks. Blue light treatment began on November 18, 2022, during the off-season for female mandarin fish. The ambient light color of the female mandarin fish broodstock was adjusted using blue LED aquaculture lighting in the LED light source control system. Throughout the culture period, the female mandarin fish broodstock were exposed to blue light with an intensity of 10 lx, and the blue light cycle was controlled by a timer. A short photoperiod of 10 L:14 D was used for the first six weeks, followed by a long photoperiod of 14 L:10 D (1 L light duration, 2 dark duration) for the last six weeks.

[0110] (6) Sampling

[0111] The experiment started on November 18, 2022 and lasted for 12 weeks. Four females were taken on the 12th week. They were randomly captured, anesthetized with MS222, and their body weights were measured. 2-3 mL of blood was collected from the tail vein using a syringe and placed in a refrigerated centrifuge tube and centrifuged at 4000 rpm for 20 minutes. The supernatant was collected and stored at -80 ° C. The estradiol concentration of female fish was determined using an ELISA kit; the melatonin concentration of female fish was determined using an ELISA kit; the vitellogenin concentration of female fish was determined using an ELISA kit; the superoxide dismutase activity of female fish liver was determined using a total superoxide dismutase assay kit (WST-1 method); the malondialdehyde content of female fish liver was determined using a malondialdehyde assay kit (TBA method); and finally, the gonadal tissue was dissected and removed.

[0112] Comparative Example 3

[0113] A method for artificially controlling off-season breeding of mandarin fish comprises the following steps:

[0114] (1) Disinfection of temporary holding ponds: Soak the temporary holding ponds and tools used in the breeding process in a 3% potassium permanganate solution for 24 hours for disinfection;

[0115] (2) Preparation of broodstock cultivation barrel: The broodstock cultivation barrel is 2m long, 2m wide and 1.6m deep, equipped with circulation facilities. The water in the cultivation barrel is circulating water, which is supplied by an indoor circulating water aquaculture system. The indoor circulating water aquaculture system consists of eight parts: aquaculture equipment, filtration equipment, water reservoir, plant purification pool, microbial treatment pool, sterilization device, temperature control equipment, and LED light source control equipment. The water in the aquaculture equipment is filtered by the filtration equipment and enters the water reservoir. The water then enters the plant purification pool and microbial treatment pool for treatment. Finally, the water is sterilized by the sterilization device before entering the broodstock cultivation barrel. The temperature control equipment controls the temperature of the indoor circulating water. The temperature control equipment includes a heating pump and a thermostat. The indoor circulating water temperature is adjusted by the heating pump and the thermostat is used for constant temperature control. The LED light source control equipment controls the indoor light color and light intensity.

[0116] (3) Screening female fish: 40 female mandarin fish parents aged 2 years and above, which are healthy, free of injury or disease, and weigh 600-900 g, are selected and disinfected by soaking in 5% sea salt for 20 minutes and then transferred to a broodstock cultivation tank in a circulating water system;

[0117] (4) Mandarin fish broodstock breeding: The density of female mandarin fish broodstock is 10kg / m 3During the mid-stage intensive culture period of the female broodstock, the broodstock were fed twice a day. According to the feeding habits of the mandarin fish, the feeding time was set at 8:00 and 17:00. Feed A was fed at 5% of the parent's body weight. During the intensive culture period of the broodstock breeding period, Feed A was replaced with Feed B. During the feeding period, the residues and feces were cleaned in time, the feeding situation of the parents was observed, and the health status was checked regularly by microscopic examination. If abnormal mandarin fish parents were found, they were isolated in time and intensive cultured in a targeted manner. Feed A or Feed B was the same as in Example 1.

[0118] (5) Cultivation of female fish by cooling and white light treatment:

[0119] Cooling began on November 18, 2022, during the off-season for female mandarin fish breeding. The water temperature for the female mandarin fish broodstock was adjusted by the temperature control equipment (heating pump and thermostat) in the indoor circulating aquaculture system to keep the water temperature at 13°C for 6 weeks. Then, within 2 weeks, the water temperature was raised to 23°C by the temperature control equipment in the indoor circulating aquaculture system and maintained for 4 weeks. White light treatment began on November 18, 2022, during the off-season for female mandarin fish breeding. The ambient light color for the female mandarin fish broodstock was adjusted by the white LED breeding lighting in the LED light source control device. The female mandarin fish broodstock were irradiated with white light with a light intensity of 10lx throughout the cultivation process, and the light cycle of the white light was controlled by a timer. A short light cycle treatment of 10L:14D was carried out in the first 6 weeks, and a long light cycle treatment of 14L:10D was carried out in the last 6 weeks (L light time D dark time). The other conditions were the same as in Example 2.

[0120] (6) Sampling

[0121] The experiment started on November 18, 2022 and lasted for 12 weeks. Four females were taken on the 12th week. They were randomly captured, anesthetized with MS222, and their body weights were measured. 2-3 mL of blood was collected from the tail vein using a syringe and placed in a refrigerated centrifuge tube and centrifuged at 4000 rpm for 20 minutes. The supernatant was collected and stored at -80 ° C. The estradiol concentration of female fish was determined using an ELISA kit; the melatonin concentration of female fish was determined using an ELISA kit; the vitellogenin concentration of female fish was determined using an ELISA kit; the superoxide dismutase activity of female fish liver was determined using a total superoxide dismutase assay kit (WST-1 method); the malondialdehyde content of female fish liver was determined using a malondialdehyde assay kit (TBA method); and finally, the gonadal tissue was dissected and removed.

[0122] Comparative Example 4

[0123] A method for artificially controlling off-season breeding of mandarin fish comprises the following steps:

[0124] (1) Disinfection of temporary holding ponds: Soak the temporary holding ponds and tools used in the breeding process in a 3% potassium permanganate solution for 24 hours for disinfection;

[0125] (2) Preparation of broodstock cultivation barrel: The broodstock cultivation barrel is 2m long, 2m wide and 1.6m deep, equipped with circulation facilities. The water in the cultivation barrel is circulating water, which is supplied by an indoor circulating water aquaculture system. The indoor circulating water aquaculture system consists of eight parts: aquaculture equipment, filtration equipment, water reservoir, plant purification pool, microbial treatment pool, sterilization device, temperature control equipment, and LED light source control equipment. The water in the aquaculture equipment is filtered by the filtration equipment and enters the water reservoir. The water then enters the plant purification pool and microbial treatment pool for treatment. Finally, the water is sterilized by the sterilization device before entering the broodstock cultivation barrel. The temperature control equipment controls the temperature of the indoor circulating water. The temperature control equipment includes a heating pump and a thermostat. The indoor circulating water temperature is adjusted by the heating pump and the thermostat is used for constant temperature control. The LED light source control equipment controls the indoor light color and light intensity.

[0126] (3) Screening female fish: 40 female mandarin fish parents aged 2 years and above, which are healthy, free of injury or disease, and weigh 600-900 g, are selected and disinfected by soaking in 5% sea salt for 20 minutes and then transferred to a broodstock cultivation tank in a circulating water system;

[0127] (4) Mandarin fish broodstock breeding: The density of female mandarin fish broodstock is 10kg / m 3 During the mid-stage intensive culture period of the female broodstock, the broodstock were fed twice a day. According to the feeding habits of the mandarin fish, the feeding time was set at 8:00 and 17:00. Feed A was fed at 5% of the parent's body weight. During the intensive culture period of the broodstock breeding period, Feed A was replaced with Feed B. During the feeding period, the residues and feces were cleaned in time, the feeding situation of the parents was observed, and the health status was checked regularly by microscopic examination. If abnormal mandarin fish parents were found, they were isolated in time and intensive cultured in a targeted manner. Feed A or Feed B was the same as in Example 1.

[0128] (5) Female fish cultured by cooling and yellow light treatment:

[0129] Cooling began on November 18, 2022, during the off-season for female mandarin fish breeding. The water temperature for the female mandarin fish broodstock was adjusted by the temperature control equipment (heating pump and thermostat) in the indoor circulating aquaculture system to maintain the water temperature at 13°C for 6 weeks. Then, within 2 weeks, the water temperature was raised to 23°C by the temperature control equipment in the indoor circulating aquaculture system and maintained for 4 weeks. Yellow light treatment began on November 18, 2022, during the off-season for female mandarin fish breeding. The ambient light color for the female mandarin fish broodstock was adjusted by the yellow LED breeding lighting in the LED light source control device. The female mandarin fish broodstock were irradiated with yellow light with a light intensity of 10lx throughout the culture process, and the light cycle of the yellow light was controlled by a timer. A short light cycle treatment of 10L:14D was carried out in the first 6 weeks, and a long light cycle treatment of 14L:10D was carried out in the last 6 weeks (L light time D dark time). The remaining conditions were the same as in Example 2.

[0130] (6) Sampling

[0131] The experiment started on November 18, 2022 and lasted for 12 weeks. Four females were taken on the 12th week. They were randomly captured, anesthetized with MS222, and their body weights were measured. 2-3 mL of blood was collected from the tail vein using a syringe and placed in a refrigerated centrifuge tube and centrifuged at 4000 rpm for 20 minutes. The supernatant was collected and stored at -80 ° C. The estradiol concentration of female fish was determined using an ELISA kit; the melatonin concentration of female fish was determined using an ELISA kit; the vitellogenin concentration of female fish was determined using an ELISA kit; the superoxide dismutase activity of female fish liver was determined using a total superoxide dismutase assay kit (WST-1 method); the malondialdehyde content of female fish liver was determined using a malondialdehyde assay kit (TBA method); and finally, the gonadal tissue was dissected and removed.

[0132] Comparative Example 5

[0133] A method for artificially controlling off-season breeding of mandarin fish comprises the following steps:

[0134] (1) Disinfection of temporary holding ponds: Soak the temporary holding ponds and tools used in the breeding process in a 3% potassium permanganate solution for 24 hours for disinfection;

[0135] (2) Preparation of broodstock cultivation barrel: The broodstock cultivation barrel is 2m long, 2m wide and 1.6m deep, equipped with circulation facilities. The water in the cultivation barrel is circulating water, which is supplied by an indoor circulating water aquaculture system. The indoor circulating water aquaculture system consists of eight parts: aquaculture equipment, filtration equipment, water reservoir, plant purification pool, microbial treatment pool, sterilization device, temperature control equipment, and LED light source control equipment. The water in the aquaculture equipment is filtered by the filtration equipment and enters the water reservoir. The water then enters the plant purification pool and microbial treatment pool for treatment. Finally, the water is sterilized by the sterilization device before entering the broodstock cultivation barrel. The temperature control equipment controls the temperature of the indoor circulating water. The temperature control equipment includes a heating pump and a thermostat. The indoor circulating water temperature is adjusted by the heating pump and the thermostat is used for constant temperature control. The LED light source control equipment controls the indoor light color and light intensity.

[0136] (3) Screening female fish: 40 female mandarin fish parents aged 2 years and above, which are healthy, free of injury or disease, and weigh 600-900 g, are selected and disinfected by soaking in 5% sea salt for 20 minutes and then transferred to a broodstock cultivation tank in a circulating water system;

[0137] (4) Mandarin fish broodstock breeding: The density of female mandarin fish broodstock is 10kg / m 3 During the mid-stage intensive culture period of the female broodstock, the broodstock were fed twice a day. According to the feeding habits of the mandarin fish, the feeding time was set at 8:00 and 17:00. Feed A was fed at 5% of the parent's body weight. During the intensive culture period of the broodstock breeding period, Feed A was replaced with Feed B. During the feeding period, the residues and feces were cleaned in time, the feeding situation of the parents was observed, and the health status was checked regularly by microscopic examination. If abnormal mandarin fish parents were found, they were isolated in time and intensive cultured in a targeted manner. Feed A or Feed B was the same as in Example 1.

[0138] (5) Female fish cooling and green light treatment cultivation:

[0139] Cooling began on November 18, 2022, during the off-season for female mandarin fish breeding. The water temperature for the female mandarin fish broodstock was adjusted by the temperature control equipment (heating pump and thermostat) in the indoor circulating aquaculture system to maintain the water temperature at 13°C for 6 weeks. Then, within 2 weeks, the water temperature was raised to 23°C by the temperature control equipment in the indoor circulating aquaculture system and maintained for 4 weeks. Green light treatment began on November 18, 2022, during the off-season for female mandarin fish breeding. The ambient light color for the female mandarin fish broodstock was adjusted by the green LED breeding lighting in the LED light source control device. The female mandarin fish broodstock were irradiated with green light with a light intensity of 10lx throughout the culture process, and the light cycle of the green light was controlled by a timer. A short light cycle treatment of 10L:14D was carried out in the first 6 weeks, and a long light cycle treatment of 14L:10D was carried out in the last 6 weeks (L light time D dark time). The remaining conditions were the same as in Example 2.

[0140] (6) Sampling

[0141] The experiment started on November 18, 2022 and lasted for 12 weeks. Four females were taken on the 12th week. They were randomly captured, anesthetized with MS222, and their body weights were measured. 2-3 mL of blood was collected from the tail vein using a syringe and placed in a refrigerated centrifuge tube and centrifuged at 4000 rpm for 20 minutes. The supernatant was collected and stored at -80 ° C. The estradiol concentration of female fish was determined using an ELISA kit; the melatonin concentration of female fish was determined using an ELISA kit; the vitellogenin concentration of female fish was determined using an ELISA kit; the superoxide dismutase activity of female fish liver was determined using a total superoxide dismutase assay kit (WST-1 method); the malondialdehyde content of female fish liver was determined using a malondialdehyde assay kit (TBA method); and finally, the gonadal tissue was dissected and removed.

[0142] Test example

[0143] 1. Data and Analysis

[0144] The data recorded in Example 1 and Comparative Examples 1-2 were calculated according to the following calculation method:

[0145] Gonad index = (gonad weight / fish body weight) * 100%. The serum estradiol concentration was determined using an ELISA kit.

[0146] The data recorded in Example 2 and Comparative Examples 3-5 are calculated according to the following calculation method:

[0147] Gonad index = (gonad weight / fish body weight) * 100%. Serum estradiol concentration was determined using an ELISA kit; melatonin concentration in female fish was determined using an ELISA kit; vitellogenin concentration in female fish was determined using an ELISA kit; superoxide dismutase activity in female fish liver was determined using a total superoxide dismutase assay kit (WST-1 method); and malondialdehyde content in female fish liver was determined using a malondialdehyde assay kit (TBA method).

[0148] The above recorded data are analyzed according to the following calculation method:

[0149] The experimental data were analyzed by one-way analysis of variance (SPSS25.0), and the data were expressed as mean ± standard deviation. The Duncan method was used for multiple comparisons between groups, and the significance level was set at 0.05.

[0150] 2. Experimental results

[0151] (1) The gonadal index of female broodstock under the conditions of Example 1 began to increase from the sampling point on December 30, 2021, from 1.06% at the beginning of the experiment to 5.23% at the end of the experiment. The gonadal index of female broodstock in the groups of Comparative Example 2 and Comparative Example 1 did not change significantly, and was 1.18% and 1.10% respectively at the end of the experiment. Figure 6 As shown in A.

[0152] The gonadal index of the male broodstock under the conditions of Example 1 began to increase from December 30, 2021, from 0.64% at the beginning of the experiment to 4.31% at the end of the experiment. The gonadal index of the male broodstock under the conditions of Comparative Example 2 gradually increased from 0.62% at the beginning of the experiment to 2.79% at the end of the experiment. The gonadal index of the male broodstock under the conditions of Comparative Example 1 did not change significantly during the entire experimental period, and was 0.76% at the end of the experiment. Figure 6 As shown in B.

[0153] (2) On November 18, 2021, December 9, 2021, and December 30, 2021, there was no significant difference in the estradiol levels of the female broodstock under the conditions of Example 1 and the estradiol levels of the female broodstock under the conditions of Comparative Example 1 and Comparative Example 2. However, on January 20, 2021 and February 10, 2021, the estradiol levels of the female broodstock under the conditions of Example 1 were significantly higher than those of Comparative Example 1 and Comparative Example 2, and reached a maximum on February 10, 2021, while the estradiol levels of the female broodstock under the conditions of Comparative Example 1 and Comparative Example 2 did not change significantly during the experiment, as shown in FIG. Figure 7 As shown in A.

[0154] After December 30, 2021, the testosterone level of male broodstock under the conditions of Example 1 began to rise, and was significantly lower than that of the experimental environment of Comparative Example 2 at this point. The difference at other times was not significant. On January 20, 2022 and February 10, 2022, the testosterone level of male broodstock under the conditions of Example 1 was significantly higher than that of male broodstock under the conditions of Comparative Example 1. The testosterone level of male broodstock under the conditions of Comparative Example 2 began to gradually increase after November 18, and was significantly higher than the testosterone level of male broodstock under the conditions of Comparative Example 1 on December 30, 2021, January 20, 2022, and February 10, 2022. Figure 7 As shown in B.

[0155] (3) Under the conditions of Example 1, female broodstock spawned naturally at the sampling point on February 10.

[0156] (4) The gonadal index of female broodstock under the conditions of Example 2 was 6.70%, which was significantly higher than that of Comparative Examples 3-5. Figure 10 shown.

[0157] (5) The serum estradiol level of female broodstock under the conditions of Example 2 was significantly higher than that of Comparative Examples 3-5. Figure 11 shown.

[0158] (6) The serum melatonin level of female broodstock under the conditions of Example 2 was significantly higher than that of Comparative Examples 3-5. Figure 12 shown.

[0159] (7) The serum vitellogenin level of female broodstock under the conditions of Example 2 was significantly higher than that of Comparative Examples 3-5. Figure 13 shown.

[0160] (8) Under the conditions of Example 2, the superoxide dismutase activity in the liver of female broodstock was significantly higher than that in Comparative Examples 4-5. Figure 14 (A) As shown; the malondialdehyde content in the liver of female broodstock was significantly lower than that in comparative examples 4-5. Figure 14 (B) shown.

[0161] (9) Under the conditions of Example 2, the female broodstock spawned naturally before sampling.

[0162] 3. Experimental Conclusion

[0163] The above experimental results show that the gonadal index of the female and male broodstock of mandarin fish using the breeding method of the present invention (Example 1) is significantly increased compared with that in Comparative Example 1 and Comparative Example 2, and the levels of estradiol and testosterone in serum are significantly increased.

[0164] The gonadal index of the female broodstock of mandarin fish in the breeding method of the present invention (Example 2) was significantly increased compared with that in Comparative Example 3, Comparative Example 4, and Comparative Example 5, and the levels of estradiol, melatonin, and vitellogenin in serum were significantly increased; the superoxide dismutase activity and the malondialdehyde content in the liver of the female broodstock of mandarin fish in the breeding method of the present invention (Example 2) were not significantly changed compared with those in Comparative Example 3; the superoxide dismutase activity in the liver of the female broodstock of mandarin fish in the breeding method of the present invention (Example 2) was significantly increased compared with those in Comparative Example 4 and Comparative Example 5, and the malondialdehyde content in the liver was significantly reduced.

[0165] In Example 1, the female broodstock of mandarin fish were able to spawn first compared with Comparative Examples 1 and 2, and in Example 2, the female broodstock of mandarin fish were able to spawn first compared with Comparative Examples 3, 4, and 5. Moreover, under the breeding conditions of Example 1 provided by the present invention, the size and appearance of the gonads of male and female mandarin fish broodstock also changed significantly.

[0166] The present invention induces the physiological functions of male broodstock to reach the reproductive level through cooling and heating treatments, and induces the physiological functions of female broodstock to reach the spawning level through cooling, heating and blue light treatments. It is highly practical and conducive to promotion and application, providing technical guarantee for faster listing of mandarin fish on the market in the same year and better market supply.

[0167] In the description of this specification, the description with reference to the term "specific embodiment" or the like means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are mutually inconsistent.

[0168] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for artificially controlling off-season breeding of mandarin fish, characterized in that: The steps include: (1) selecting mandarin fish broodstock, transferring them to broodstock cultivation tanks, and culturing them in an indoor environment; (2) Controlling the indoor environmental temperature to maintain the water temperature in the culture tanks of male and female mandarin fish at 13°C for 6 weeks, then controlling the water temperature to rise to 23°C within 2 weeks and maintain it for 4 weeks to induce spawning of female mandarin fish or gonadal maturation of male mandarin fish; Step (2) further includes the step of light-inducing the female broodstock of mandarin fish throughout the whole process: controlling the indoor ambient light color, and irradiating the female broodstock of mandarin fish with a blue light with a light intensity of 10 lx throughout the whole culture process; In step (2), the female and male broodstock of mandarin fish are raised separately, and the parent density is 10 kg / m 3 During the intensive culture period of the middle stage of parent fish rearing, feed twice a day. According to the feeding habits of mandarin fish, the feeding time is set at 8:00 and 17:00, and feed feed A at 5% of the parent fish body weight. During the intensive culture period of parent fish breeding, feed A is replaced with feed B. During the rearing period, the residues and feces are cleaned in time, the feeding situation of the parents is observed, and the health status is checked regularly by microscopic examination. If abnormal mandarin fish parents are found, they will be isolated in time and targeted intensive culture is carried out; The feed A, calculated by mass, includes 15 parts of fermented soybean meal, 5 parts of soybean protein concentrate, 51 parts of fish meal, 8 parts of starch, 10 parts of meat quality improver, 2 parts of multivitamins, 2 parts of multiminerals, 2 parts of attractant, 2 parts of seaweed polysaccharide and 3 parts of yeast powder; The feed B, calculated by mass, includes 15 parts of fermented soybean meal, 8 parts of soybean protein concentrate, 41 parts of fish meal, 8 parts of starch, 9 parts of fish oil, 13 parts of reproductive enhancer, 2 parts of multivitamins, 2 parts of multiminerals, and 2 parts of seaweed polysaccharides; In the feed A, 10 parts of the meat quality improver include the following raw materials in parts by weight: 3 parts of fish oil, 0.5 parts of krill oil, 2 parts of soybean oil, 1 part of linseed oil, 0.5 parts of dried longan powder, 1 part of pig liver powder, 0.8 parts of kelp powder, and 1.2 parts of houttuynia cordata; 2 parts of the attractant include the following raw materials in parts by weight: 1 part of fish slurry, 0.3 parts of squid paste, 0.3 parts of allicin, and 0.4 parts of brewer's yeast; In the feed B, 13 parts of the reproduction enhancer are made from the following raw materials in parts by weight: 1 part of krill oil, 1 part of shrimp meal, 3 parts of oyster powder, 1 part of black wolfberry, 1 part of Ligustrum lucidum, 3 parts of liquorice, 1 part of kelp powder, and 2 parts of houttuynia cordata; In the feed A and feed B, the compound vitamins contain vitamin B1, 30 mg; vitamin B2, 60 mg; vitamin B6, 30 mg; vitamin B 12 , 0.22mg; Vitamin D3, 5mg; Vitamin E, 160mg; Vitamin K3, 50mg; Folic acid, 20mg; Biotin, 2.5mg; Calcium pantothenate, 100mg; 35% vitamins, 250mg; Niacin, 200mg; Rice husk powder, 999mg; The composite minerals contain 10 mg of MnSO4, 10 mg of MgSO4, 95 mg of KCl, 165 mg of NaCl, 20 mg of ZnSO4, 1 mg of KI, 12.5 mg of CuSO4, 105 mg of FeSO4, 0.1 mg of Na2SeO3, and 1.5 mg of Co per kilogram of diet.

2. The method for artificially controlling off-season breeding of mandarin fish according to claim 1, wherein: In step (1), the mandarin fish broodstock are temporarily raised in a temporary holding pond, the temporary holding pond and the tools used in mandarin fish breeding are soaked and disinfected in a 3% potassium permanganate solution for 24 hours in advance, the broodstock cultivation tank is 2 meters long, 2 meters wide, and 1.6 meters deep, and is equipped with a circulating water system. The cultivation water body is circulating water, and the circulating water is supplied by an indoor circulating water culture system.

3. The method for artificially controlling off-season breeding of mandarin fish according to claim 2, wherein: The indoor circulating aquaculture system includes eight parts: breeding equipment, filtering equipment, a water reservoir, a plant purification pool, a microbial treatment pool, a sterilization device, a temperature control device and an LED light source control device. The water in the breeding equipment is filtered by the filtering equipment and enters the water reservoir. Then, the water enters the plant purification pool and the microbial treatment pool in turn for treatment. Finally, the water is sterilized by the sterilization device and then enters the broodstock breeding barrel. The temperature control device controls the indoor circulating water temperature, and the LED light source control device controls the indoor light color and light intensity.

4. The method for artificially controlling off-season breeding of mandarin fish according to claim 3, wherein: The temperature control equipment includes a heating pump and a thermostat, which adjusts the indoor circulating water temperature through the heating pump and uses the thermostat to perform constant temperature control; the LED light source control equipment includes a blue LED aquaculture lighting lamp and a timer, which adjusts the light intensity and uses the timer to control the light cycle of the blue light.

5. The method for artificially controlling off-season breeding of mandarin fish according to claim 1, wherein: In step (1), male and female mandarin fish parents of 2 years old or older with a healthy body shape, no injuries or diseases and a weight of 600-900 g are selected.

6. The method for artificially controlling off-season breeding of mandarin fish according to claim 5, characterized in that: The selected male and female mandarin fish parents must be soaked and disinfected in 5% sea salt for 20 minutes before being transferred to a broodstock breeding tank equipped with a circulating water system.

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