Artificial breeding method for hybrid of silver drum fish and golden drum fish

Abstract

The invention relates to the technical field of hybridization of silver drum fish and golden drum fish, and in particular to an artificial propagation method of a hybrid of silver drum fish and golden drum fish, comprising four steps of parent fish cultivation, artificial induced spawning, artificial hatching and seedling cultivation. The artificial propagation method of the hybrid of silver drum fish and golden drum fish can effectively prevent golden drum fish and silver drum fish from being infected with streptococci, reduce the mortality of golden drum fish and silver drum fish, and avoid economic losses, and can effectively provide an excellent spawning environment for female golden drum fish, which is beneficial to improving the fertilization rate of golden drum fish. At the same time, the hybrid offspring of the golden drum fish and silver drum fish has euryhaline properties, can adapt to seawater and freshwater environments, has strong disease resistance, high survival rate, is easy to raise, has bright body color and pattern, is smaller than both parents, and can maintain a petite body shape for a long time, and is very suitable for development as a new variety of ornamental fish.

Description

Technical Field

[0001] The invention relates to the technical field of hybridization of silver drum fish and golden drum fish, in particular to an artificial breeding method for hybrids of silver drum fish and golden drum fish. Background Art

[0002] The body of the golden drumfish is slightly oval, flattened and tall, with a deep notch between the hard spines and soft rays of the dorsal fin, brown body surface, silvery-white ventral edge, many dark round spots on the body, and an adult fish is about 30 cm long; the silver drumfish, scientific name: multi-lineated butterflyfish, is a marine fish with ornamental and edible value. It is an omnivorous fish. The silver drumfish has an oblate body, 20 to 40 cm long, silvery white body, and dozens of sparse black round spots on both sides of the abdomen. The silver drumfish can live in fresh water and sea water at the same time, and it is difficult to breed in an aquarium. A new hybrid fish can be obtained by hybridizing the silver drumfish and the golden drumfish. This hybrid fish has the advantages of both the golden drumfish and the silver drumfish, with brighter body color and more beautiful patterns. It has a good development prospect in the field of ornamental fish and its economic value is considerable.

[0003] In this regard, Chinese patent publication number: CN113647345A discloses a method for factory-based artificial breeding of golden drum fish, which realizes factory-based artificial breeding of golden drum fish through fish pond laying, water quality management, stocking density, feeding and ecological environment construction, and achieves the goals of rapid growth and high survival rate of golden drum fish. In the present invention, the survival rate is higher than 90%, and the average weight of golden drum fish fry after 5 months of breeding is higher than 290g.

[0004] However, there are still some problems when using the above invention. First, during the hybridization process of golden drum fish and silver drum fish, golden drum fish and silver drum fish are easily infected with streptococci, resulting in the death of a large number of golden drum fish and silver drum fish, causing economic losses. In addition, one of the stimulation conditions required for female golden drum fish to spawn is water flow, and the above invention cannot effectively provide a good spawning environment for female golden drum fish, which is not conducive to obtaining a higher fertilization rate.

[0005] Therefore, it is urgent to design an artificial breeding method for the hybrid of silver drum fish and golden drum fish to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide an artificial breeding method for a hybrid of silver drum fish and golden drum fish, so as to solve the problems mentioned in the above background technology that golden drum fish and silver drum fish are easily infected with streptococci, resulting in the death of a large number of golden drum fish and silver drum fish, causing economic losses, and failing to effectively provide a good spawning environment for female golden drum fish, which is not conducive to obtaining a higher fertilization rate.

[0007] To achieve the above object, the present invention provides the following technical solution: an artificial propagation method of a hybrid of silver drum fish and golden drum fish, comprising the following steps:

[0008] S1. Broodstock Cultivation

[0009] (1). Conventional Cultivation of Broodstock

[0010] a. Catch wild silver drum fish and golden drum fish fry with a length of 2 - 3 cm in the sea;

[0011] b. Put the fry into the pond for acclimation cultivation, and release them at a density of 2,500 silver drum fish and 2,500 golden drum fish per mu;

[0012] c. Feed the pond twice a day, and add vitamin C and enrofloxacin hydrochloride to the feed;

[0013] d. Accelerate the water flow in the pond every 6 hours;

[0014] e. Conduct conventional cultivation for two years;

[0015] (2). Pre - spawning Intensification Cultivation

[0016] a. Time for selecting broodstock: Select broodstock in the pond in June of the second year of conventional cultivation;

[0017] b. Selection of male donors: Select male silver drum fish with a body weight greater than 250 g in the pond as male donors;

[0018] c. Selection of female recipients: Select female golden drum fish with a body weight greater than 400 g in the pond as female recipients;

[0019] d. Selection of breeding environment: Transfer male donors and female recipients into indoor water tanks, and cultivate them in separate tanks. Control the water temperature at 28 - 30 °C, the salinity at 24 - 29 ‰, and the dissolved oxygen in the water tank above 5 mg / L;

[0020] e. Control of intensification cultivation time: About 35 days;

[0021] f. Accelerate the water flow in the indoor water tank every 3 hours;

[0022] S2. Artificial Induction of Spawning

[0023] (1). Months for induction of spawning: From the fifth month to the seventh month of the second year of conventional cultivation;

[0024] (2). Use hormone injection for inducing spawning;

[0025] (3). Adopt the method of artificial insemination;

[0026] S3. Artificial Incubation

[0027] (1). Preparation for incubation

[0028] d. Disinfect and filter the incubation water source;

[0029] e. Adjust the pH value of hatching water: 7.6-7.8;

[0030] f. Dissolved oxygen content: 5mg / L or more;

[0031] (4) Adjust the salinity of hatching water: 19-25‰;

[0032] (5) Adjust the hatching water temperature to 29°C;

[0033] S4. Seedling cultivation

[0034] (1) The artificially hatched fry are placed in a nursery pond for breeding;

[0035] (2) Feed the fish with starter feed on the third day of seedling raising.

[0036] Preferably, chlorine dioxide is added to the pond and the drug concentration in the pond reaches 0.3 g / m 3 .

[0037] Preferably, in step S1c, vitamin B and vitamin E are added to the feed, and the amount of vitamin C added is 10% of the daily diet, and the amount of enrofloxacin hydrochloride added to the feed is 25 mg / kg.

[0038] Preferably, in step S1 (1)-d, a water pump is installed in the pond, the output end of the water pump sprays water into the pond, and a protective net is fixed to the output end of the water pump, and the mesh diameter of the protective net is less than 2 cm.

[0039] Preferably, the output end of the water pump is arranged at the bank of the pond.

[0040] Preferably, in step S1 (1)-e, a winter shed is built on the pond during the conventional breeding of broodstock in winter.

[0041] Preferably, in step S2 (2), human chorionic gonadotropin (HCG), 10000 IU / vial, luteinizing hormone releasing hormone (LHRH) A 2 , 100ug / vial, dimethoate (DOM), 50mg / vial, in step S2 (3), dry insemination is adopted.

[0042] Preferably, the hormone injection is divided into two injections, the first injection is 15ug / kg luteinizing hormone releasing hormone (LHRH) A 2 , after an interval of 18 hours, a second injection of 1500 IU / kg human chorionic gonadotropin (HCG) and 4 mg / kg of DOM was injected.

[0043] Preferably, in step S3 (1)-a, the hatching water source is disinfected with quicklime and left to stand for 5 days.

[0044] Preferably, in step S4 (2), rotifer bait is selected and algae are added.

[0045] Compared with the prior art, the invention has the beneficial effects that the artificial breeding method of the hybrid of silver drum fish and golden drum fish can effectively prevent golden drum fish and silver drum fish from being infected with streptococci through the breeding method of parent fish cultivation, artificial induced spawning, artificial hatching and seed cultivation, reduce the mortality rate of golden drum fish and silver drum fish, avoid economic losses, and at the same time effectively provide an excellent spawning environment for female golden drum fish, which is beneficial to improving the fertilization rate of golden drum fish.

[0046] (1) The present invention can effectively prevent golden drum fish and silver drum fish from being infected with streptococci by mixing vitamin C and enrofloxacin hydrochloride into feed and using chlorine dioxide to disinfect ponds, thereby reducing the disease mortality of golden drum fish and silver drum fish.

[0047] (2) The present invention uses a water pump in the pond to spray water into the pond to form a water flow, thereby providing an excellent spawning environment for female golden drum fish, which is beneficial to improving the fertilization rate of golden drum fish.

[0048] (3) The present invention hybridizes golden drum fish and silver drum fish so that the hybrid offspring have euryhaline properties, can adapt to seawater and freshwater environments, have strong disease resistance, high survival rate, are easy to raise, have bright body color and patterns, are smaller than their parents, and can maintain a small body shape for a long time, making them very suitable for development as new varieties of ornamental fish. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of a hybrid offspring of golden drum fish and silver drum fish of the present invention;

[0050] Figure 2 The present invention provides a weight table of golden drum fish, silver drum fish and their hybrid offspring;

[0051] Figure 3 The following is a table showing the hatchability of female broodstock in Examples 1-3 of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0053] Embodiments provided by the present invention:

[0054] Example 1

[0055] An artificial breeding method for a hybrid of silver drum fish and golden drum fish comprises the following steps:

[0056] S1. Broodstock cultivation

[0057] (1) Conventional breeding of broodstock:

[0058] a. Catch wild silver drum and golden drum fry of 2 cm in length in the sea;

[0059] b. The fry are placed in ponds for domestication and cultivation, with a stocking density of 2,500 silver drum and 2,500 golden drum per acre;

[0060] c. Feed the pond twice a day, and add vitamin C and enrofloxacin hydrochloride to the feed;

[0061] d. Accelerate the water flow in the pond every 6 hours;

[0062] e. Conventional cultivation for two years;

[0063] After domestication and cultivation, they are cultured in ponds with a salinity of 24-29‰, with a stocking density of 2,500 per mu. After about a year of culture, there are large differences in the size of individual fish, so they are divided into two ponds for breeding. Feeding begins at 8 am and 4 pm every day, with a feeding amount of 3-5% of the body weight of the fish in the pond. In typhoons, heavy rains and other weather conditions, the feeding amount is appropriately reduced according to the feeding situation. After two years of breeding, the female fish can reach a body length of 24cm and the male fish can reach 19cm, reaching sexual maturity. Since golden drum is a warm water fish, a wintering shed must be built in winter to keep the water temperature above 18°C. Generally, the water temperature in winter is between 18°C ​​and 22°C, and in summer it is between 28 and 32°C. The aerator is turned on for 2 hours every afternoon and early morning.

[0064] (2) Prenatal intensive training

[0065] a. Broodstock selection time: Broodstock selection in ponds is carried out in June of the second year of conventional breeding;

[0066] b. Donor selection: Select male silver drum fish weighing more than 250g in the pond as male donors;

[0067] c. Receptor selection: Select female golden drum fish weighing more than 400 g in the pond as female receptors;

[0068] d. Selection of breeding environment: Move the male donor and the female recipient into an indoor pool, and cultivate the male donor and the female recipient in separate pools. The water temperature should be controlled at 28°C, the salinity should be controlled at 24-29‰, and the dissolved oxygen content in the pool should be above 5mg / L.

[0069] e. Strengthen cultivation time control: about 35 days;

[0070] f. Accelerate the water flow in the indoor pool every 3 hours;

[0071] S2. Artificial induction of labor

[0072] (1) Inducing spawning month: May to July of the second year of conventional breeding;

[0073] (2) Use hormone injections to induce labor;

[0074] (3) Use dry insemination method;

[0075] S3. Artificial incubation

[0076] (1) Preparation for hatching

[0077] a. Disinfection and filtration of hatching water sources;

[0078] b. Adjust the pH value of the hatching water source: 7.6;

[0079] c. Dissolved oxygen content: 5 mg / L or more;

[0080] (6) Adjust the salinity of hatching water: 19‰;

[0081] (7) Adjust the hatching water temperature to 29°C;

[0082] S4. Seedling cultivation

[0083] (1) The artificially hatched fry are placed in a nursery pond for breeding;

[0084] (2) Feed the fish with starter feed on the third day of seedling raising.

[0085] Add chlorine dioxide to the pond and make the concentration of the drug in the pond reach 0.3g / m 3 .

[0086] In step S1c, vitamin B and vitamin E are added to the feed, and the added amount of vitamin C is 10% of the daily diet, and the amount of enrofloxacin hydrochloride is added to the feed at 25 mg / kg. By mixing vitamin C and enrofloxacin hydrochloride into the feed and using chlorine dioxide to disinfect the pond, it is possible to effectively prevent golden drum fish and silver drum fish from being infected with streptococci, thereby reducing the disease mortality of golden drum fish and silver drum fish.

[0087] In step S1 (1)-d, a water pump is installed in the pond, and the output end of the water pump sprays water into the pond. A protective net is fixed to the output end of the water pump, and the mesh diameter of the protective net is less than 2 cm to prevent fry from swimming into the water pump from the output end of the water pump. At the same time, the water pump in the pond sprays water into the pond to form a water flow, thereby providing an excellent spawning environment for female golden drum fish, which is beneficial to improving the fertilization rate of golden drum fish. The output end of the water pump is set at the bank of the pond. Such a setting is determined according to the spawning habits of golden drum fish and silver drum fish.

[0088] In step S1 (1)-e, during the conventional breeding of broodstock, a winter shed is built on the pond in winter, which can increase the temperature of the pond surface and prevent the temperature from being too low in winter, causing the death of golden drum fish and silver drum fish due to temperature inadaptability.

[0089] In step S2 (2), human chorionic gonadotropin (HCG), 10000 IU / vial, luteinizing hormone releasing hormone (LHRH) A 2 , 100ug / tube, dioxin (DOM), 50mg / tube, in step S2 (3), it should be noted that luteinizing hormone releasing hormone (LHRH) A 2 It is a 10-peptide compound with the structural formula C 56 H 78 N 16 O 12 , with a relative molecular weight of 1167. Its main component is a peptide substance (LHRH) secreted from the hypothalamus. This hormone can induce the anterior pituitary of animals to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and has the effects of both luteinizing hormone and follicle-stimulating hormone. The main function of human chorionic gonadotropin (HCG) is to stimulate the corpus luteum, which is beneficial to the continuous secretion of estrogen and progesterone to promote the formation of uterine decidua and make the placenta grow and mature. The role of dione (DOM) is to inhibit or eliminate the effect of gonadotropin-releasing hormone inhibitory factor (GRIF) on hypothalamic gonadotropin-releasing hormone (GNRH), thereby enhancing the secretion of pituitary gonadotropin (GTH). It is often used in combination with luteinizing hormone-releasing hormone analogue (LHRHA) in the induced labor of golden drum fish and silver drum fish.

[0090] The hormone injection is divided into two injections. The first injection is 15ug / kg luteinizing hormone releasing hormone (LHRH) A 2 , 18 hours later, a second injection of 1500IU / kg of human chorionic gonadotropin (HCG) and 4mg / kg of DOM was injected. It is worth mentioning that the applicable standard for the amount of hormones is based on the conclusion drawn from experiments. When LHRH-A 2When the dose reaches 20μg / kg, a small number of female fish can lay eggs. After increasing the dose, the induced spawning rate did not increase, the effect time was still about 40 hours, and the fertilization rate was 0. Considering that excessive amounts of exogenous hormones have a great impact on the physiological regulation of fish, it may cause damage to the endocrine regulation of fish. Therefore, it is not suitable to choose a single LHRH-A in the artificial induced spawning of silver drum and golden drum. 2 At the same time, when HCG was injected alone, the rate of induction of labor increased with the increase of HCG dosage. When the HCG content was 2000UI / kg, the rate of induction of labor was 16.7%, the effect time was 36h, the fertilization rate was 0, and the eggs produced could not be fertilized. Therefore, it is not appropriate to choose HCG injection alone for artificial induction of labor in silver drum and golden drum. 2 When mixed with HCG, the rate of induction of labor can reach up to 83.3%. 2 The injection dose reached 15μg / kg, and the HCG dose was 1500UI / kg. The average effect time was 22h, and the fertilization rate was 13%. When the drug injection dose was less than 15μg / kg LHRH-A 2 When the dose is 15 μg / kg LHRH-A, the induced labor rate does not exceed 50%, and the fertilization rate does not exceed 6%. 2 and 1500UI / kg HCG, the induced labor rate was 83.3% and the fertilization rate was 13%. 2 When the dosage was 20μg / kg and 1500UI / kg HCG, the induced labor rate reached 83.3%, but the fertilization rate decreased. 2 When the mixture of DOM and 15 μg / kg LHRH-A was injected once, the induced labor rate did not exceed 50%. 2 The mixed drug of DOM 4mg / kg had an induced labor rate of 33.3% and a fertilization rate of 4%. After two injections, 15μg / kg LHRH-A 2 The first injection, 18 hours later, the second injection of 4mg / kg DOM had the best effect, with an induced labor rate of 50.0%, an effect duration of 15 hours, and a fertilization rate of 31%. 2 When the dosage was 20μg / kg and the DOM dosage was 4mg / kg, the induced labor rate was 50% and the fertilization rate was 15%.

[0091] In step S3 (1)-a, the hatching water source is disinfected with quicklime and left to stand for 5 days.

[0092] In step S4 (2), rotifer bait is selected and algae are added.

[0093] Embodiment 2:

[0094] An artificial breeding method for a hybrid of silver drum fish and golden drum fish comprises the following steps:

[0095] S1. Broodstock cultivation

[0096] (1) Conventional breeding of broodstock:

[0097] a. Catch wild silver drum and golden drum fry with a length of 2.5 cm in the sea;

[0098] b. The fry are placed in ponds for domestication and cultivation, with a stocking density of 2,500 silver drum and 2,500 golden drum per acre;

[0099] c. Feed the pond twice a day, and add vitamin C and enrofloxacin hydrochloride to the feed;

[0100] d. Accelerate the water flow in the pond every 6 hours;

[0101] e. Conventional cultivation for two years;

[0102] After domestication and cultivation, they are cultured in pond water with a salinity of 24-29‰, with a stocking density of 2,500 per mu. After about a year of culture, there are large differences in the size of individual fish, so they are divided into two ponds for breeding. Feeding begins at 8 am and 4 pm every day, and the feeding amount is 3-5% of the body weight of the fish in the pond. In typhoons, heavy rains and other weather conditions, the feeding amount is appropriately reduced according to the feeding situation. After two years of breeding, the female fish can reach 24cm in length and the male fish can reach 19cm, reaching sexual maturity. Since golden drum fish is a warm water fish, a wintering shed must be built in winter to keep the water temperature above 18℃. Generally, the water temperature in winter is between 18℃ and 22℃, and in summer it is between 28 and 32℃. The aerator is turned on for 2 to 3 hours every afternoon and early morning.

[0103] (2) Prenatal intensive training

[0104] a. Broodstock selection time: Broodstock selection in ponds is carried out in June of the second year of conventional breeding;

[0105] b. Donor selection: Select male silver drum fish weighing more than 250g in the pond as male donors;

[0106] c. Receptor selection: Select female golden drum fish weighing more than 400 g in the pond as female receptors;

[0107] d. Selection of breeding environment: Move the male donor and the female recipient into an indoor pool, and cultivate the male donor and the female recipient in separate pools. The water temperature is controlled at 29°C, the salinity is controlled at 26‰, and the dissolved oxygen content in the pool is above 5mg / L.

[0108] e. Strengthen the cultivation time control: about 35 days;

[0109] f. Accelerate the water flow in the indoor pool every 3 hours;

[0110] S2. Artificial induction of labor

[0111] (1) Inducing spawning month: May to July of the second year of conventional breeding;

[0112] (2) Use hormone injections to induce labor;

[0113] (3) Use semi-dry insemination method;

[0114] S3. Artificial incubation

[0115] (1) Preparation for hatching

[0116] a. Disinfection and filtration of hatching water sources;

[0117] b. Adjust the pH value of hatching water: 7.7;

[0118] c. Dissolved oxygen content: 5 mg / L or more;

[0119] (8) Adjust the salinity of hatching water: 23‰;

[0120] (9) Adjust the hatching water temperature to 29°C;

[0121] S4. Seedling cultivation A 2

[0122] (1) The artificially hatched fry are placed in a nursery pond for breeding;

[0123] (2) Feed the fish with starter feed on the third day of seedling raising.

[0124] Add chlorine dioxide to the pond and make the concentration of the drug in the pond reach 0.3g / m 3 .

[0125] In step S1c, vitamin B and vitamin E are added to the feed, and the added amount of vitamin C is 10% of the daily diet, and the amount of enrofloxacin hydrochloride is added to the feed at 25 mg / kg. By mixing vitamin C and enrofloxacin hydrochloride into the feed and using chlorine dioxide to disinfect the pond, it is possible to effectively prevent golden drum fish and silver drum fish from being infected with streptococci, thereby reducing the disease mortality of golden drum fish and silver drum fish.

[0126] In step S1 (1)-d, a water pump is installed in the pond, and the output end of the water pump sprays water into the pond. A protective net is fixed to the output end of the water pump, and the mesh diameter of the protective net is less than 2 cm to prevent fry from swimming into the water pump from the output end of the water pump. At the same time, the water pump in the pond sprays water into the pond to form a water flow, thereby providing an excellent spawning environment for female golden drum fish, which is beneficial to improving the fertilization rate of golden drum fish. The output end of the water pump is set at the bank of the pond. Such a setting is determined according to the spawning habits of golden drum fish and silver drum fish.

[0127] In step S1 (1)-e, during the conventional breeding of broodstock, a winter shed is built on the pond in winter, which can increase the temperature of the pond surface and prevent the temperature from being too low in winter, causing the death of golden drum fish and silver drum fish due to temperature inadaptability.

[0128] In step S2 (2), human chorionic gonadotropin (HCG), 10000 IU / vial, luteinizing hormone releasing hormone (LHRH) A 2 , 100ug / vial, DOM, 50mg / vial, in step S2 (3), semi-dry insemination is adopted, it should be noted that luteinizing hormone releasing hormone (LHRH) A 2 It is a 10-peptide compound with the structural formula C 56 H 78 N 16 O 12 , with a relative molecular weight of 1167. Its main component is a peptide substance (LHRH) secreted from the hypothalamus. This hormone can induce the anterior pituitary of animals to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and has the effects of both luteinizing hormone and follicle-stimulating hormone. The main function of human chorionic gonadotropin (HCG) is to stimulate the corpus luteum, which is beneficial to the continuous secretion of estrogen and progesterone to promote the formation of uterine decidua and make the placenta grow and mature. The role of dione (DOM) is to inhibit or eliminate the effect of gonadotropin-releasing hormone inhibitory factor (GRIF) on hypothalamic gonadotropin-releasing hormone (GNRH), thereby enhancing the secretion of pituitary gonadotropin (GTH). It is often used in combination with luteinizing hormone-releasing hormone analogue (LHRHA) in the induced labor of golden drum fish and silver drum fish.

[0129] The hormone injection is divided into two injections. The first injection is 15ug / kg luteinizing hormone releasing hormone (LHRH) A 2 , 18 hours later, a second injection of 1500IU / kg of human chorionic gonadotropin (HCG) and 4mg / kg of DOM was injected. It is worth mentioning that the applicable standard for the amount of hormones is based on the conclusion drawn from experiments. When LHRH-A 2When the dose reaches 20μg / kg, a small number of female fish can lay eggs. After increasing the dose, the induced spawning rate did not increase, the effect time was still about 40 hours, and the fertilization rate was 0. Considering that excessive amounts of exogenous hormones have a great impact on the physiological regulation of fish, it may cause damage to the endocrine regulation of fish. Therefore, it is not suitable to choose a single LHRH-A in the artificial induced spawning of silver drum and golden drum. 2 At the same time, when HCG was injected alone, the rate of induction of labor increased with the increase of HCG dosage. When the HCG content was 2000UI / kg, the rate of induction of labor was 16.7%, the effect time was 36h, the fertilization rate was 0, and the eggs produced could not be fertilized. Therefore, it is not appropriate to choose HCG injection alone for artificial induction of labor in silver drum and golden drum. 2 When mixed with HCG, the rate of induction of labor can reach up to 83.3%. 2 The injection dose reached 15μg / kg, and the HCG dose was 1500UI / kg. The average effect time was 22h, and the fertilization rate was 13%. When the drug injection dose was less than 15μg / kg LHRH-A 2 When the dose is 15 μg / kg LHRH-A, the induced labor rate does not exceed 50%, and the fertilization rate does not exceed 6%. 2 and 1500UI / kg HCG, the induced labor rate was 83.3% and the fertilization rate was 13%. 2 When the dosage was 20μg / kg and 1500UI / kg HCG, the induced labor rate reached 83.3%, but the fertilization rate decreased. 2 When the mixture of DOM and 15 μg / kg LHRH-A was injected once, the induced labor rate did not exceed 50%. 2 The mixed drug of DOM 4mg / kg had an induced labor rate of 33.3% and a fertilization rate of 4%. After two injections, 15μg / kg LHRH-A 2 The first injection, 18 hours later, the second injection of 4mg / kg DOM had the best effect, with an induced labor rate of 50.0%, an effect duration of 15 hours, and a fertilization rate of 31%. 2 When the dosage was 20μg / kg and the DOM dosage was 4mg / kg, the induced labor rate was 50% and the fertilization rate was 15%.

[0130] In step S3 (1)-a, the hatching water source is disinfected with quicklime and left to stand for 5 days.

[0131] In step S4 (2), rotifer bait is selected and algae are added.

[0132] Example 3

[0133] An artificial breeding method for a hybrid of silver drum fish and golden drum fish comprises the following steps:

[0134] S1. Broodstock cultivation

[0135] (1) Conventional breeding of broodstock:

[0136] a. Catch wild silver drum and golden drum fry of 3 cm in length in the sea;

[0137] b. The fry are placed in ponds for domestication and cultivation, with a stocking density of 2,500 silver drum and 2,500 golden drum per acre;

[0138] c. Feed the pond twice a day, and add vitamin C and enrofloxacin hydrochloride to the feed;

[0139] d. Accelerate the water flow in the pond every 6 hours;

[0140] e. Conventional cultivation for two years;

[0141] After domestication and cultivation, they are cultured in pond water with a salinity of 24-29‰, with a stocking density of 2,500 per mu. After about a year of culture, there are large differences in the size of individual fish, so they are divided into two ponds for breeding. Feeding begins at 8 am and 4 pm every day, and the feeding amount is 3-5% of the body weight of the fish in the pond. In typhoons, heavy rains and other weather conditions, the feeding amount is appropriately reduced according to the feeding situation. After two years of breeding, the female fish can reach 24cm in length and the male fish can reach 19cm, reaching sexual maturity. Since golden drum fish is a warm water fish, a wintering shed must be built in winter to keep the water temperature above 18℃. Generally, the water temperature in winter is between 18℃ and 22℃, and in summer it is between 28 and 32℃. The aerator is turned on for 2 to 3 hours every afternoon and early morning.

[0142] (2) Prenatal intensive training

[0143] a. Broodstock selection time: Broodstock selection in ponds is carried out in June of the second year of conventional breeding;

[0144] b. Donor selection: Select male silver drum fish weighing more than 250g in the pond as male donors;

[0145] c. Receptor selection: Select female golden drum fish weighing more than 400 g in the pond as female receptors;

[0146] d. Selection of breeding environment: Move the male donor and the female recipient into an indoor pool, and cultivate the male donor and the female recipient in separate pools. The water temperature is controlled at 30°C, the salinity is controlled at 29‰, and the dissolved oxygen content in the pool is above 5mg / L.

[0147] e. Strengthen the cultivation time control: about 35 days;

[0148] f. Accelerate the water flow in the indoor pool every 3 hours;

[0149] S2. Artificial induction of labor

[0150] (1) Inducing spawning month: May to July of the second year of conventional breeding;

[0151] (2) Use hormone injections to induce labor;

[0152] (3) Wet insemination method;

[0153] S3. Artificial incubation

[0154] (1) Preparation for hatching

[0155] g. Disinfection and filtration of hatching water sources;

[0156] h. Adjust the pH value of the hatching water source: 7.8;

[0157] i. Dissolved oxygen content: 5mg / L or more;

[0158] (10) Adjust the salinity of hatching water: 25‰;

[0159] (11) Adjust the hatching water temperature to 29°C;

[0160] S4. Seedling cultivation

[0161] (1) The artificially hatched fry are placed in a nursery pond for breeding;

[0162] (2) Feed the fish with starter feed on the third day of seedling raising.

[0163] Add chlorine dioxide to the pond and make the concentration of the drug in the pond reach 0.3g / m 3 .

[0164] In step S1c, vitamin B and vitamin E are added to the feed, and the added amount of vitamin C is 10% of the daily diet, and the amount of enrofloxacin hydrochloride is added to the feed at 25 mg / kg. By mixing vitamin C and enrofloxacin hydrochloride into the feed and using chlorine dioxide to disinfect the pond, it is possible to effectively prevent golden drum fish and silver drum fish from being infected with streptococci, thereby reducing the disease mortality of golden drum fish and silver drum fish.

[0165] In step S1 (1)-d, a water pump is installed in the pond, and the output end of the water pump sprays water into the pond. A protective net is fixed to the output end of the water pump, and the mesh diameter of the protective net is less than 2 cm to prevent fry from swimming into the water pump from the output end of the water pump. At the same time, the water pump in the pond sprays water into the pond to form a water flow, thereby providing an excellent spawning environment for female golden drum fish, which is beneficial to improving the fertilization rate of golden drum fish. The output end of the water pump is set at the bank of the pond. Such a setting is determined according to the spawning habits of golden drum fish and silver drum fish.

[0166] In step S1 (1)-e, during the conventional breeding of broodstock, a winter shed is built on the pond in winter, which can increase the temperature of the pond surface and prevent the temperature from being too low in winter, causing the death of golden drum fish and silver drum fish due to temperature inadaptability.

[0167] In step S2 (2), human chorionic gonadotropin (HCG), 10000 IU / vial, luteinizing hormone releasing hormone (LHRH) A 2 , 100ug / tube, dioxin (DOM), 50mg / tube, in step S2 (3), it should be noted that luteinizing hormone releasing hormone (LHRH) A 2 It is a 10-peptide compound with the structural formula C 56 H 78 N 16 O 12 , with a relative molecular weight of 1167. Its main component is a peptide substance (LHRH) secreted from the hypothalamus. This hormone can induce the anterior pituitary of animals to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and has the effects of both luteinizing hormone and follicle-stimulating hormone. The main function of human chorionic gonadotropin (HCG) is to stimulate the corpus luteum, which is beneficial to the continuous secretion of estrogen and progesterone to promote the formation of uterine decidua and make the placenta grow and mature. The role of dione (DOM) is to inhibit or eliminate the effect of gonadotropin-releasing hormone inhibitory factor (GRIF) on hypothalamic gonadotropin-releasing hormone (GNRH), thereby enhancing the secretion of pituitary gonadotropin (GTH). It is often used in combination with luteinizing hormone-releasing hormone analogue (LHRHA) in the induced labor of golden drum fish and silver drum fish.

[0168] The hormone injection is divided into two injections. The first injection is 15ug / kg luteinizing hormone releasing hormone (LHRH) A 2 , 18 hours later, a second injection of 1500IU / kg of human chorionic gonadotropin (HCG) and 4mg / kg of DOM was injected. It is worth mentioning that the applicable standard for the amount of hormones is based on the conclusion drawn from experiments. When LHRH-A 2When the dose reaches 20μg / kg, a small number of female fish can lay eggs. After increasing the dose, the induced spawning rate did not increase, the effect time was still about 40 hours, and the fertilization rate was 0. Considering that excessive amounts of exogenous hormones have a great impact on the physiological regulation of fish, it may cause damage to the endocrine regulation of fish. Therefore, it is not suitable to choose a single LHRH-A in the artificial induced spawning of silver drum and golden drum. 2 At the same time, when HCG was injected alone, the rate of induction of labor increased with the increase of HCG dosage. When the HCG content was 2000UI / kg, the rate of induction of labor was 16.7%, the effect time was 36h, the fertilization rate was 0, and the eggs produced could not be fertilized. Therefore, it is not appropriate to choose HCG injection alone for artificial induction of labor in silver drum and golden drum. 2 When mixed with HCG, the rate of induction of labor can reach up to 83.3%. 2 The injection dose reached 15μg / kg, and the HCG dose was 1500UI / kg. The average effect time was 22h, and the fertilization rate was 13%. When the drug injection dose was less than 15μg / kg LHRH-A 2 When the dose is 15 μg / kg LHRH-A, the induced labor rate does not exceed 50%, and the fertilization rate does not exceed 6%. 2 and 1500UI / kg HCG, the induced labor rate was 83.3% and the fertilization rate was 13%. 2 When the dosage was 20μg / kg and 1500UI / kg HCG, the induced labor rate reached 83.3%, but the fertilization rate decreased. 2 When the mixture of DOM and 15 μg / kg LHRH-A was injected once, the induced labor rate did not exceed 50%. 2 The mixed drug of DOM 4mg / kg had an induced labor rate of 33.3% and a fertilization rate of 4%. After two injections, 15μg / kg LHRH-A 2 The first injection, 18 hours later, the second injection of 4mg / kg DOM had the best effect, with an induced labor rate of 50.0%, an effect duration of 15 hours, and a fertilization rate of 31%. 2 When the dosage was 20μg / kg and the DOM dosage was 4mg / kg, the induced labor rate was 50% and the fertilization rate was 15%.

[0169] In step S3 (1)-a, the hatching water source is disinfected with quicklime and left to stand for 5 days.

[0170] In step S4 (2), rotifer bait is selected and algae are added.

[0171] The results of the above-mentioned embodiments 1 to 3 show that the artificial propagation method of the present invention can effectively prevent golden drum fish and silver drum fish from being infected with streptococci, reduce the mortality of golden drum fish and silver drum fish, avoid economic losses, and effectively provide an excellent spawning environment for female golden drum fish, which is beneficial to improving the fertilization rate of golden drum fish. It is worth mentioning that the three embodiments of the present invention respectively adopt different insemination methods, and all three artificial insemination methods are tested. The first dry insemination: take out the female and male fish respectively with a scoop net, drain the water, wipe the water on the surface of the fish with a towel, squeeze the eggs into a dry basin first, then squeeze in a few drops of semen, and stir evenly. Then add 20‰ seawater to the basin, stir for 3 to 5 minutes, and finally rinse several times and pour into the hatching bucket for hatching;

[0172] The second type of semi-dry insemination: squeeze the male fish semen into a beaker containing an appropriate amount of 0.85% saline to dilute it, then pour it into a basin containing fish eggs and stir evenly, finally add 20‰ seawater and stir for 2 to 3 minutes;

[0173] The third wet insemination method: squeeze the fish eggs and semen into a basin filled with 20‰ seawater at the same time, stirring while squeezing;

[0174] After the three different insemination methods mentioned above, such as Figure 3 As shown, it is found that the eggs of silver drum fish and golden drum fish that are normally fertilized are bright and translucent in color, the egg membrane absorbs water and swells, and is suspended in the water, while the unfertilized eggs are dull in color, turn white, and sink to the bottom of the water. In addition, in the artificial hybridization process of silver drum fish and golden drum fish, the dry insemination method is adopted, and the fertilization rate is the best, reaching 72.1%, the fertilization rate of semi-dry insemination is 3.7%, and the effect of wet insemination is the worst, with a fertilization rate of only 1.3%. However, considering the production cost control of the enterprise, different fertilization methods have different costs. In the three embodiments of the present invention, the dry insemination cost is the highest, while the wet insemination cost is the lowest. Therefore, different fertilization methods can be selected according to the actual production needs of the enterprise. In addition, by hybridizing golden drum fish and silver drum fish, the hybrid offspring has wide salt tolerance, can adapt to seawater and freshwater environments, has strong disease resistance, high survival rate, and is easy to raise, such as Figure 1 As shown in the figure, the hybrid offspring has bright body color and pattern, the vertical spines on the back are sparse and short compared with the silver drum fish, the black spots on both sides of the abdomen are more obvious and the number is also scarce. Compared with the parents, the hybrid offspring has a higher ornamental value, and the weight of the hybrid offspring is obviously smaller than that of the male silver drum fish and the female golden drum fish. Figure 2 As shown, the hybrid offspring can maintain their petite size for a long time and are very suitable for development as a new variety of ornamental fish.

[0175] It should be noted that the hybrid offspring of silver drum and golden drum have smaller caliber and poorer activity in the early stage of feeding, and may not be able to ingest all the rotifers. Adding an appropriate amount of algae can increase the nutrition of the hybrid offspring of silver drum and golden drum, and the abundant and dense phytoplankton can promote the growth and survival of the fry of the hybrid offspring of silver drum and golden drum. Because these algae contain polyunsaturated fatty acid fragments, when choosing rotifers as the main feeding bait for the hybrid offspring of silver drum and golden drum, adding algae appropriately will help the survival of the fry of silver drum and golden drum.

[0176] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An artificial breeding method for a hybrid of silver drum fish and golden drum fish, Features: The following steps are involved: S1. Broodstock cultivation (1) Conventional breeding of broodstock: a. Catch wild silver drum and golden drum fry with a length of 2 to 3 cm in the sea; b. The fry are placed in ponds for domestication and cultivation, with a stocking density of 2,500 silver drum and 2,500 golden drum per acre; c. Feed the pond twice a day, and add vitamin C and enrofloxacin hydrochloride to the feed; d. Accelerate the water flow in the pond every 6 hours; e. Conventional cultivation for two years; (2) Prenatal intensive training a. Broodstock selection time: Broodstock selection in ponds is carried out in June of the second year of conventional breeding; b. Donor selection: Select male silver drum fish weighing more than 250g in the pond as male donors; c. Receptor selection: Select female golden drum fish weighing more than 400 g in the pond as female receptors; d. Selection of breeding environment: Move the male donor and the female recipient into an indoor pool, and cultivate the male donor and the female recipient in separate pools. The water temperature should be controlled at 28-30℃, the salinity should be controlled at 24-29‰, and the dissolved oxygen content in the pool should be above 5mg / L. e. Strengthen the cultivation time control: about 35 days; f. Accelerate the water flow in the indoor pool every 3 hours; S2. Artificial induction of labor (1) Inducing spawning month: May to July of the second year of conventional breeding; (2) Use hormone injections to induce labor; (3) Artificial insemination; S3. Artificial incubation (1) Preparation for hatching a. Disinfection and filtration of hatching water sources; b. Adjust the pH value of hatching water: 7.6-7.8; c. Dissolved oxygen content: 5 mg / L or more; (2) Adjust the salinity of hatching water: 19-25‰; (3) Adjust the hatching water temperature to 29°C; S4. Seedling cultivation (1) The artificially hatched fry are placed in a nursery pond for breeding; (2) Feeding of open-mouthed bait on the third day of seedling raising; Add chlorine dioxide to the pond and make the concentration of the drug in the pond reach 0.3g / m 3 ; In step S1c, vitamin B and vitamin E are added to the feed, and the amount of vitamin C added is 10% of the diet, and the amount of enrofloxacin hydrochloride added to the feed is 25 mg / kg; In step S1 (1)-d, a water pump is installed in the pond, and the output end of the water pump sprays water into the pond, and a protective net is fixed to the output end of the water pump, and the mesh diameter of the protective net is less than 2 cm; The output end of the water pump is set at the bank of the pond. In the step S1 (1)-e, a winter shed is built on the pond during the conventional breeding of broodstock in winter. In the step S2 (2), human chorionic gonadotropin (HCG) is selected, 10000 IU / vial, luteinizing hormone releasing hormone (LHRH) A 2 , 100 μg / vial, dioxin (DOM), 50 mg / vial, in step S2 (3), dry insemination is adopted, and the hormone injection is divided into two injections, the first injection is 15 μg / kg luteinizing hormone releasing hormone (LHRH) A 2 , after an interval of 18 hours, inject a second injection of 1500 IU / kg of human chorionic gonadotropin (HCG) and 4 mg / kg of DOM. In step S3 (1)-a, use quicklime to disinfect the hatching water source and let it stand for 5 days. In step S4 (2), select rotifer bait and add algae.

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