Method for on-site rapid artificial insemination of wild sal-family large yellow croaker

Abstract

The invention provides a method for on-site rapid artificial insemination of wild sal-family large yellow croakers, and belongs to the technical field of aquatic animal breeding. According to the method, wild parent fishes are captured in the breeding season of the sal-family pseudosciaena crocea; selecting sexually mature male parent fishes on a capturing site, and collecting seminal fluid for later use; after manual semen collection is finished, female parent fishes with sexual maturity are selected, and fish eggs are collected; performing artificial insemination to obtain high-quality fertilized eggs; the artificial insemination comprises the following steps: adding seminal fluid into the roes, then adding natural seawater, stirring, and finally washing with the natural seawater. According to the method, key links of the whole artificial insemination process are comprehensively regulated and controlled, so that the purposes of obtaining high-quality fertilized eggs and carrying out artificial fry breeding by utilizing the parent fish of the wild sal ammoniac large yellow croaker are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of aquatic animal breeding, and in particular relates to a method for on-site rapid artificial insemination of wild Naozhou large yellow croaker. Background Art

[0002] my country's yellow croaker is generally divided into three groups according to population ecology, namely the Fujian-Yuedong yellow croaker represented by Ningde, Fujian, the Daiqu yellow croaker in Zhoushan, Zhejiang, and the Naozhou yellow croaker mainly in the coastal waters of Naozhou, Guangdong. Among them, the yellow croakers of the Fujian-Yuedong and Daiqu populations have been developed and studied, and have formed industrial scales in Fujian, Zhejiang and other places, while the Naozhou yellow croaker has not yet been developed and utilized. The Naozhou yellow croaker has a unique advantage in adapting to the high sea conditions of deep-sea aquaculture. This feature makes it a more advantageous variety in the development of deep-sea aquaculture in Guangdong. After large-scale aquaculture, it will effectively solve the industrial development bottleneck of the Fujian-Yuedong yellow croaker and the Zhejiang Daiqu yellow croaker, which have poor high temperature resistance and cannot be fully aquacultured in the South China Sea. It is expected to become an important development variety for deep-sea aquaculture in the South China Sea in the future.

[0003] During the breeding season, the Naozhou large yellow croaker migrates to the nearshore waters in groups and lays eggs in fixed spawning grounds. Due to the destruction of the spawning grounds and overfishing, the germplasm resources of wild Naozhou large yellow croaker have shown obvious signs of decline. Breaking through the artificial breeding technology of Naozhou large yellow croaker and obtaining high-quality fertilized eggs is one of the key issues to be solved. There are two main ways to solve this problem: one is to capture wild broodstock with gonad development to stage IV in shallow waters (water depth of 8-10 meters), control the transportation process, artificially induce spawning and artificially collect eggs for fertilization to obtain high-quality fertilized eggs, but the capture process of wild broodstock is more stressful and the survival time is shorter under artificial breeding conditions; the other method is to capture wild broodstock with mature eggs in deep waters (20-40 meters), and obtain high-quality fertilized eggs through rapid artificial insemination on site. However, during the on-site artificial insemination process, the fertilization success rate is often low because the spawning process of the parent fish can only be maintained for a short time, the testis and ovary develop asynchronously, the eggs are immature if squeezed out too early, and over-mature if squeezed out a little later. This has seriously restricted the development of artificial breeding of the Naozhou giant yellow croaker. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for rapid on-site artificial insemination of wild Naozhou large yellow croaker to improve the fertilization rate.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A method for rapid on-site artificial insemination of wild Naozhou large yellow croaker comprises the following steps:

[0007] Capture wild broodstock during the breeding season of the Naozhou giant yellow croaker; select sexually mature male broodstock at the capture site and collect semen for later use; after artificial semen collection, select sexually mature female broodstock and collect fish eggs; perform artificial insemination to obtain high-quality fertilized eggs; the artificial insemination includes: add semen to fish eggs, then add natural seawater to stir, and finally rinse with natural seawater.

[0008] Preferably, the wild broodstock are caught in the waters near Naozhou Island, Zhanjiang, Guangdong at a depth of 20-40 m during the neap tides in the ninth and tenth lunar months.

[0009] Preferably, after artificial insemination is completed, the fertilized eggs are stirred in natural seawater for 3-4 minutes, and then allowed to stand, and high-quality fertilized eggs floating on the water surface are collected.

[0010] Preferably, the semen is stored at 2-4°C and the sperm motility is 70-80%.

[0011] Preferably, the ratio of semen to fish eggs is 1 mL: 8000-12000 eggs.

[0012] Preferably, the gonads of the wild broodstock of the Naozhou large yellow croaker have developed to stage V.

[0013] Preferably, the net-pulling speed when capturing the wild broodstock is 1-2 m / s, and during this period, the net may catch large yellow croaker of the Naozhou tribe and place it in a live water tank.

[0014] Preferably, after the artificial insemination is completed, the fertilized eggs are transported back to the land-based breeding farm in fish fry plastic bags.

[0015] Preferably, the high-quality fertilized eggs obtained by artificial insemination are hatched in a hatching bucket to obtain wild Naozhou large yellow croaker fry.

[0016] Preferably, the incubation conditions are: water temperature 24-26°C, salinity 28-30, pH 8.2-8.5, dissolved oxygen 5.5-6.5 mg / L, light intensity 800-1100 Lux

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a method for rapid on-site artificial insemination of wild Naozhou large yellow croaker, which comprehensively regulates the key links of the whole process from wild parent fish capture, artificial semen collection, artificial insemination and collection of high-quality fertilized eggs, and effectively improves the fertilization rate and hatching rate of wild large yellow croaker. The present invention helps to achieve the purpose of obtaining high-quality fertilized eggs using wild Naozhou large yellow croaker parent fish and carrying out artificial seed breeding through comprehensive regulation of the key links of the whole process of artificial insemination. DETAILED DESCRIPTION

[0019] The invention provides a method for on-site rapid artificial insemination of wild Naozhou large yellow croaker, comprising the following steps: capturing wild broodstock during the breeding season of Naozhou large yellow croaker; selecting sexually mature male broodstock at the capture site and collecting semen for standby use; after the artificial semen collection is completed, selecting sexually mature female broodstock and collecting fish eggs; performing artificial insemination to obtain high-quality fertilized eggs.

[0020] The present invention uses a single-layer drift gillnet (mesh size of about 6.5 cm) to capture wild broodstock in the spawning ground of the Naozhou tribe yellow croaker near Naozhou Island in Zhanjiang, Guangdong during the low tide in the ninth and tenth lunar months. The wild broodstock are captured at a net-pulling speed of 1-2 m / s. Based on the habit of yellow croaker living in the middle and lower layers of the ocean, the present invention controls the net-pulling speed, reduces the influence of water pressure stress on wild broodstock, and is conducive to improving its survival rate.

[0021] As an practicable method, when the wild broodstock described in the present invention are captured, the net is raised about 1 hour after being released. During this period, if the net contains large yellow croakers of the Naozhou ethnic group, the net is cut with scissors and the large yellow croakers are gently put into a live water tank, and the live water tank is oxygenated to a dissolved oxygen level of 5.0-6.0 mg / L.

[0022] After the wild broodstock are caught, sexually mature male fish are selected from the live water tank to collect semen, and the gonads of the male fish have developed to stage V. As an practicable method, the semen collection of the present invention includes selecting broodstock with no obvious bulge in the abdomen, wrapping the head with a wet towel, wiping the cloaca with dry gauze, lightly pressing the abdomen with the thumb toward the tail to squeeze out milky white semen, and using a syringe (5 mL) without a needle to absorb semen at the cloaca.

[0023] The semen of the present invention is stored at 2-4°C. As an practicable method, the present invention uses a portable incubator to store semen.

[0024] The method takes a small amount of semen and dilutes it, observes the movement ratio of sperm under a microscope, and selects semen with a sperm activity rate of 70-80% for artificial insemination.

[0025] After the artificial semen collection is completed, sexually mature female fish whose gonads have developed to stage V are selected from the live water tank to collect fish eggs. In a specific embodiment of the present invention, female broodstock with swollen abdomen, red genital pores and obvious ovarian outlines are selected.

[0026] The method comprises the following steps: wiping off mucus on the body surface of a sexually mature female fish, placing the abdomen toward a clean container, gently squeezing the abdomen, and squeezing the female fish eggs into the container for artificial insemination.

[0027] The artificial insemination of the present invention comprises: adding semen to fish eggs and stirring rapidly, wherein the ratio of semen to fish eggs is 1 mL: 8000-12000 grains, preferably 1 mL: 9000-11000 grains, and the rapid stirring time is 25-35 s, preferably 28-32 s, so that semen and fish eggs are fully in contact; then adding 500 mL of natural seawater filtered by sedimentation and stirring, preferably stirring for 2-3 min, so that the fish eggs are fertilized, and finally rinsed with natural seawater, and the natural seawater is rinsed 2-3 times to wash away the unfertilized semen. The natural seawater described in the present invention is natural seawater filtered by sedimentation. In the present invention, after the natural seawater is allowed to stand for 12 hours, the upper layer of water is extracted for filtration, and the filtering method is a quartz sand filter purchased from Shijiazhuang Gongquan Water Treatment Technology Co., Ltd.

[0028] After artificial insemination is completed, the fertilized eggs are transferred to a container filled with seawater and oxygenated to 5.0-6.0 mg / L for temporary storage. After artificial insemination is completed, the fertilized eggs are transported back to the land-based breeding farm in a fry plastic bag. The fry plastic bag is filled with pure oxygen to 5.0-6.0 mg / L of dissolved oxygen and then packed and transported back to the land-based breeding farm. As an implementable method, a thickened double-layer fry plastic bag is selected, and its specification is 25*50 cm.

[0029] After the fertilized eggs of the present invention are transported back to the land-based breeding farm, they are transferred into a hatching bucket for processing. The fertilized eggs are stirred in natural seawater for 3-4 minutes, and then left to stand, and high-quality fertilized eggs floating on the water surface are collected.

[0030] In the present invention, high-quality fertilized eggs obtained by artificial insemination are hatched in a hatching bucket to obtain wild Naozhou large yellow croaker fry, and the hatching conditions are: water temperature 24-26°C, salinity 28-30, pH 8.2-8.5, dissolved oxygen 5.5-6.5 mg / L, light intensity 800-1100 Lux, preferably water temperature 25°C, salinity 29, pH 8.3, light intensity 900-1000 Lux.

[0031] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0032] Example 1

[0033] 2023 Wild Naozhou Yellow Croaker Live Rapid Artificial Insemination

[0034] Wild broodstock are collected during the low tide period in the ninth month of the lunar calendar, in the spawning grounds of the Naozhou tribe yellow croaker near Naozhou Island in Zhanjiang, Guangdong, in the sea area with a water depth of 20-40 meters. Deep-water single-layer drift gillnets (net length 40-50m, net height 1.5m, mesh size 6.5cm) are used. The net is pulled up 1 hour after it is released, and the pulling speed is controlled at 1m / s. If broodstock are encountered during the pulling process, the net is immediately cut, and the broodstock are gently placed in the live water tank, and oxygenated to 5.5mg / L of dissolved oxygen for temporary storage.

[0035] Artificial semen collection: After the wild broodstock are caught, sexually mature male fish are selected from the live water tank. Specifically, broodstock with no obvious bulge in the abdomen are selected. The head is wrapped with a wet towel, and the cloaca is wiped dry with dry gauze. The abdomen is gently pressed with the thumb toward the tail to squeeze out milky white semen. A syringe (5mL) without the needle is used to absorb the semen at the cloaca and put it in a portable incubator (the temperature is controlled at 3°C). A small amount of semen is taken for dilution and then the sperm motility is observed under a microscope. Semen with a sperm motility rate of 70-80% is used for artificial insemination.

[0036] Artificial insemination: After the artificial semen collection is completed, sexually mature female fish are selected from the live water tank. Specifically, female broodstock with swollen abdomen, red genital pore and obvious ovarian outline are selected. The mucus on the surface of the fish body is wiped clean with dry gauze, with the abdomen facing the plastic basin, and the abdomen is gently squeezed to squeeze the female fish eggs into a clean plastic basin, and then 1mL of semen is added for 10,000 eggs. The eggs are stirred quickly for 30 seconds to allow full contact between sperm and eggs, and then 500mL of natural seawater that has been filtered and precipitated is added. The eggs are stirred for 2 minutes to fertilize. Finally, they are rinsed twice with natural seawater, transferred to a plastic barrel filled with seawater and oxygenated to 5.5mg / L for temporary storage. After the artificial insemination is completed, thickened double-layer fry plastic bags (25*50cm) are used, filled with pure oxygen to 5.5mg / L for packaging and transported back to land-based farms.

[0037] Collect high-quality fertilized eggs: transport the fertilized eggs back to the land-based breeding farm and process them in the hatching bucket. Gently rotate the water counterclockwise for 3.5 minutes, then let it stand for 20 minutes, collect the high-quality fertilized eggs floating on the water surface and the bad eggs deposited to the bottom, record the number of floating eggs and the number of sedimented eggs, and calculate the fertilization rate; the high-quality fertilized eggs are transferred to a hatching bucket of one cubic water body for incubation. The incubation conditions are water temperature 25℃, salinity 28, pH 8.3, dissolved oxygen 5.5mg / L, light intensity 1000Lux, and the hatching rate is calculated after the fry hatch.

[0038] In this embodiment, 100 g of fertilized eggs were collected, of which 35.4 g were high-quality fertilized eggs, accounting for 35.4%, and the hatching rate of high-quality fertilized eggs was 72.6%.

[0039] Example 2

[0040] 2024 Wild Naozhou Yellow Croaker Live Rapid Artificial Insemination

[0041] Wild broodstock are collected during the low tide period in the tenth month of the lunar calendar, in the spawning grounds of the Naozhou tribe yellow croaker near Naozhou Island in Zhanjiang, Guangdong, in the sea area with a water depth of 20-40 meters. Deep-water single-layer drift gillnets (net length 40-50m, net height 1.5m, mesh size 6.5cm) are used. The net is pulled up 1 hour after it is released, and the pulling speed is controlled at 1.5m / s. If broodstock are encountered during the pulling process, the net is immediately cut, and the broodstock are gently and slowly placed in the live water tank, and oxygenated to 6.0mg / L of dissolved oxygen for temporary storage.

[0042] Artificial semen collection: After the wild broodstock are caught, sexually mature male fish are selected from the live water tank. Specifically, broodstock with no obvious bulge in the abdomen are selected. The head is wrapped with a wet towel, and the cloaca is wiped dry with dry gauze. The abdomen is gently pressed with the thumb toward the tail to squeeze out milky white semen. A syringe (5mL) without the needle is used to absorb the semen at the cloaca and put it in a portable incubator (the temperature is controlled at 4°C). A small amount of semen is taken for dilution and then the sperm motility is observed under a microscope. Semen with a sperm motility rate of 70-80% is used for artificial insemination.

[0043] Artificial insemination: After the artificial semen collection is completed, sexually mature female fish are selected from the live water tank. Specifically, female broodstock with swollen abdomen, red genital pore and obvious ovarian outline are selected. The mucus on the surface of the fish body is wiped clean with dry gauze, with the abdomen facing the plastic basin, and the abdomen is gently squeezed to squeeze the female fish eggs into a clean plastic basin, and then 1mL of semen is added for 9500 eggs, and the sperm and eggs are quickly stirred for 25s to allow full contact, and then 500mL of natural seawater filtered by sedimentation is added, and stirred for 3min to fertilize the eggs. Finally, rinse with natural seawater 3 times, transfer to a plastic barrel filled with seawater and oxygenated to 6.0mg / L of dissolved oxygen for temporary storage. After all artificial insemination is completed, use thickened double-layer fry plastic bags (25*50cm), fill with pure oxygen to 6.0mg / L of dissolved oxygen, pack and transport back to land-based farms.

[0044] Collect high-quality fertilized eggs: transport the fertilized eggs back to the land-based breeding farm and process them in the hatching bucket. Gently rotate the water counterclockwise for 4 minutes, then let it stand for 25 minutes, collect the high-quality fertilized eggs floating on the water surface and the bad eggs deposited to the bottom, record the number of floating eggs and the number of sedimented eggs, and calculate the fertilization rate; the high-quality fertilized eggs are transferred to a hatching bucket of one cubic water body for incubation. The incubation conditions are water temperature 26℃, salinity 29, pH 8.4, dissolved oxygen 6.5mg / L, light intensity 800Lux, and the hatching rate is calculated after the fry hatch.

[0045] In this embodiment, 284 g of fertilized eggs were collected, of which 120.7 g were high-quality fertilized eggs, accounting for 42.5%, and the hatching rate of high-quality fertilized eggs was 76.4%.

[0046] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for rapid on-site artificial insemination of wild Naozhou large yellow croaker, characterized in that: The steps include: Capture wild broodstock during the breeding season of the Naozhou giant yellow croaker; select sexually mature male broodstock at the scene of capture and collect semen for future use; after artificial semen collection, select sexually mature female broodstock and collect eggs; Perform artificial insemination to obtain high-quality fertilized eggs; The artificial insemination comprises: adding semen into fish eggs, then adding natural seawater for stirring, and finally washing with natural seawater.

2. The method according to claim 1, characterized in that Wild broodstock were captured at a depth of 20-40 m near Naozhou Island, Zhanjiang, Guangdong during the neap tides in the ninth and tenth lunar months.

3. The method according to claim 1, characterized in that After artificial insemination is completed, the fertilized eggs are stirred in natural seawater for 3-4 minutes, then left to stand, and high-quality fertilized eggs floating on the water surface are collected.

4. The method according to claim 1, characterized in that: The semen is stored at 2-4°C, and the sperm motility rate is 70-80%.

5. The method according to claim 1, characterized in that The ratio of semen to fish eggs is 1 mL: 8000-12000 eggs.

6. The method according to claim 1, characterized in that The gonads of the wild broodstock of the Naozhou large yellow croaker have developed to stage V.

7. The method according to claim 1, characterized in that The net-pulling speed when the wild broodstock are captured is 1-2 m / s. During the process, the net may catch large yellow croakers of the Naozhou tribe and place them in a live water tank.

8. The method according to claim 1, characterized in that After the artificial insemination is completed, the fertilized eggs are transported back to the land-based breeding farm in fish fry plastic bags.

9. The method according to claim 1, characterized in that: The high-quality fertilized eggs obtained by artificial insemination are hatched in a hatching bucket to obtain wild Naozhou large yellow croaker fry.

10. The method according to claim 9, characterized in that The incubation conditions are: water temperature 24-26° C., salinity 28-30, pH 8.2-8.5, dissolved oxygen 5.5-6.5 mg / L, and light intensity 800-1100 Lux.