A large-scale breeding method for saddle grouper

Abstract

The present invention provides a large-scale breeding method for saddle grouper, which relates to the technical field of grouper breeding. The method comprises digestion treatment of fertilized eggs and indoor and outdoor relay breeding. The digestion treatment of the fertilized eggs can facilitate the breaking of the membranes of the fish flowers; the rotifer eggs obtained by feeding the fry after strengthening during the indoor breeding process can provide the fry with more nutrients, which is conducive to the opening of the fry; the fry are cultured indoors when their physical conditions are weak in the early stages of flowering and metamorphosis, and then placed in outdoor ponds for breeding after they have a certain resistance, which can effectively improve the resistance of the fry. In addition, during outdoor breeding, the water body is continuously disinfected by using an electrolytic seawater chlorine dioxide generator to remove ammonia nitrogen and prevent the fry from being affected by pathogenic microorganisms. Under the above effects, the breeding survival rate can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of grouper breeding, and in particular to a large-scale breeding method for grouper. Background Art

[0002] Groupers are carnivorous, reef-dwelling fish found in tropical and subtropical waters. They belong to the family Epinephelus, in the order Perciformes. The family comprises 16 genera and 165 species, representing a rich phenotype. Known for their delicious and nutritious meat, they are often called "chicken of the sea" and are an important edible fish species in my country's southern coastal areas. Guangdong, Hainan, and Fujian provinces have long been important sources of grouper seed and commercial fish farming. According to my country's Fisheries Statistical Yearbook, my country's annual grouper production has reached 241,000 tons, ranking fourth among marine fish. Grouper is a key commercial aquaculture species in my country.

[0003] The saddleback grouper (Epinephelus lanceolatus), also known as dragon grouper, giant grouper, and dragon grouper, is the largest species in the grouper family, reaching a maximum weight of 400 kg and a length of 2.7 meters. Due to its growth advantage, the saddleback grouper is an important paternal parent in grouper hybrid breeding. The Tiger-Dragon hybrid (brown-spotted grouper♀×saddleback grouper♂), the Cloud hybrid (clouded grouper♀×saddleback grouper♂), and the Flower Dragon hybrid (humpback grouper♀×saddleback grouper♂) all use the saddleback grouper as the paternal parent. The Tiger-Dragon hybrid is a key aquaculture grouper in my country, with a market share of approximately 70%. Saddleback groupers are known for their delicious meat and firm, smooth skin, making them a delicacy. However, the small size of saddleback grouper eggs, resulting in poor quality, small fry size, and low survival rates, remain unresolved, hindering the stable and large-scale production of high-quality fry.

[0004] In view of this, it is necessary to design an improved large-scale breeding method for saddle grouper to solve the above problems. Summary of the Invention

[0005] The invention aims to provide a large-scale breeding method for Epinephelus saddleback.

[0006] To achieve the above-mentioned object of the invention, the present invention provides a method for large-scale breeding of saddleback grouper, comprising the following steps:

[0007] S1. Digest the fertilized eggs to facilitate the rupture of the membrane;

[0008] S2, using nutrient solution to enhance the ultrafine Brachionus plicatilis rotifer, collecting rotifer eggs and feeding them to the hatched fry;

[0009] S3, fish flower and metamorphosis early stage indoor cultivation:

[0010] In 20-50m 3 Prepare clean seawater with a salinity of 10‰ and a water temperature of 28-32℃ in an indoor pond. Place an aeration head per square meter and add 1×10 6 cfu / m 3 After the Bacillus, put the treated fertilized eggs; after the fry open, add 20ppm of Chlorella in the pond, 1×10 7 cfu / m 3 Lactic acid bacteria; 12 hours after the fry hatch, feed rotifer eggs to facilitate hatching. The final concentration of rotifer eggs in the tank is 10 / mL. Feed rotifer eggs every 8 hours to maintain the final concentration of 10 / mL. Feed continuously for 4 days. The lighting is 2000-3000 lux full-spectrum light, which is on 24 hours uninterruptedly. From the 5th to the 8th day after hatching, feed ultramicroscopic Brachionus plicatilis rotifers with a long diameter of less than 140μm and a short diameter of less than 90μm. Start feeding Artemia nauplii on the 9th day after hatching.

[0011] On the 13th day after hatching, inject 0.5ppm vitamin C and 0.1ppm eugenol, turn off all light sources in the hatching space to maintain a completely dark environment, use a searchlight with a light intensity greater than 5000lux to induce the fry to gather, collect the fry, and transport them to the outdoor pond;

[0012] S4, outdoor cultivation in the middle stage of metamorphosis:

[0013] After the outdoor pond is disinfected, the fry are placed in the outdoor pond and fed with brine shrimp nauplii until they are full; 21 days after hatching, they are fed with copepods until they are full; 35 days after hatching, fully developed fry are obtained.

[0014] Preferably, in step S2, the enhancement of ultrafine plicatilaginous rotifers is carried out as follows: adding seawater with a salinity of 10‰ to the hatching bucket, adding 2ppm trichloroisocyanuric acid, and vigorously aerating until there is no residual chlorine for standby use; adding nutrient mother solution according to the weight of the water in the hatching bucket, the mass ratio of water to nutrient mother solution is 100:1, and the temperature of the hatching bucket is controlled to be 31-32°C and the pH is 5.6-6.3; after mixing evenly, the ultrafine plicatilaginous rotifers are added to the hatching bucket for enhancement, using pure oxygen to provide oxygen, the dissolved oxygen is not less than 12mg / L, and the enhancement is carried out for 12h. After the enhancement is completed, the rotifers are fished out and placed again in another hatching bucket with nutrient mother solution for secondary enhancement, and the enhancement time is 12h.

[0015] Preferably, the preparation method of the nutrient mother solution is as follows: 10g / L of Nannochloropsis powder, 1g / L of Haematococcus pluvialis powder, 10g / L of Schizochytrium powder, 10g / L of Antarctic krill oil, 1g / L of Liyang brand aquatic special compound premix feed, 2g / L of emulsifier monoglyceride, add purified water, and blend in a homogenizer to form an emulsion.

[0016] Preferably, in step S2, the rotifer eggs are collected as follows: the enhanced rotifers are picked up, drained, and deep-sea fish oil is added at 10% of the weight of the rotifers; the rotifers are placed in a 200-mesh sieve, and a 300-500 mesh sieve is placed under the sieve to receive the rotifer eggs, the 300-500 mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating, and the rotifers are repeatedly rinsed with seawater at a pressure of 0.4 MPa until the rotifer eggs are detached and flow through the 200-mesh sieve into the 300-500 mesh sieve, thereby realizing the collection of the rotifer eggs; the collected rotifer eggs need to be disinfected with 0.5 ppm of sodium hypochlorite, cleaned, and placed in aerated clean seawater with a salinity of 10‰ and a temperature of 15°C for standby use.

[0017] Preferably, in step S1, the digestion treatment is performed according to the following steps: injecting clean seawater with a salinity of 25-33‰ into an incubation bucket with a volume of 500-1000L, vigorously aerating, and adding 3ppm povidone iodine; injecting clean seawater with a salinity of 25-33‰ into another incubation bucket with a volume of 500-1000L, vigorously aerating, adding 0.5ppm trypsin, 1ppm glutathione, 1ppm ethylenediaminetetraacetic acid, and 0.2ppm zinc chloride, and adjusting the pH of the seawater to 7.8-8.5 and controlling the temperature to 28-32°C;

[0018] Place the fertilized eggs in an incubation bucket with povidone iodine, remove the fertilized eggs after 15 minutes of aeration, and wash them with clean seawater. Then place them in an incubation bucket with trypsin, remove the fertilized eggs after 30 minutes of aeration, and wash them with clean seawater containing 0.5ppm fetal bovine serum. Then place the treated fertilized eggs in an indoor pool prepared in advance.

[0019] Preferably, in step S4, the outdoor pond disinfection treatment is carried out as follows: a seawater electrolysis chlorine dioxide generator and 150-200m 3 / h protein skimmer is used to circulate and disinfect outdoor pond seawater. The circulation process current is 40-80A and the voltage is 2-6V. Water in the pond is continuously extracted for disinfection. The chlorine production of the discharged seawater is 0.1-0.15mg / L. The water residence time in the protein skimmer is not less than 2min. At the discharge end, a waterwheel-type oxygenator is added to push the seawater in the pond and promote the mixing of electrolyzed seawater and the original water in the pond. The daily circulating water volume is 60-80% of the total water volume. Gram-negative bacteria are not higher than 20 cfu / mL, and Gram-positive bacteria are not higher than 50 cfu / mL.

[0020] The beneficial effects of the present invention are:

[0021] The present invention provides a large-scale breeding method for saddle grouper, which includes digestion treatment of fertilized eggs and indoor and outdoor relay breeding. The digestion treatment of the fertilized eggs can facilitate the breaking of the fish membrane; during the indoor breeding process, the rotifer eggs obtained after the fry are strengthened are fed to the fry, which can provide more nutrients for the fry and facilitate the opening of the fry; by culturing the fry indoors when the fry are weak in the early stage of bloom and metamorphosis, and placing them in outdoor ponds for breeding after they have a certain resistance, the resistance of the fry can be effectively improved. In addition, during outdoor breeding, the water body is continuously disinfected by using an electrolytic seawater chlorine dioxide generator to remove ammonia nitrogen and prevent the fry from being affected by pathogenic microorganisms. Under the above effects, the breeding survival rate can be improved. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to specific embodiments.

[0023] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions of the present invention are shown in the text, while other details that are not closely related to the present invention are omitted.

[0024] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0025] The large-scale breeding method of Epinephelus saddleback provided by the present invention comprises the following steps:

[0026] S1. Digest the fertilized eggs to facilitate the rupture of the membrane:

[0027] Clean seawater with a salinity of 25-33‰ is injected into a 500-1000L incubation bucket, vigorously aerated, and then 3ppm povidone-iodine is added. Clean seawater with a salinity of 25-33‰ is injected into another 500-1000L incubation bucket, vigorously aerated, and then 0.5ppm trypsin, 1ppm glutathione, 1ppm ethylenediaminetetraacetic acid, and 0.2ppm zinc chloride are added. The pH of the seawater is adjusted to 7.8-8.5, and the temperature is controlled to 28-32°C. In this step, povidone-iodine is used for disinfection, trypsin is used to digest eggshells, glutathione is used to treat oxidative and harmful substances during digestion, ethylenediaminetetraacetic acid is used to complex with zinc chloride to improve the stability of zinc chloride in the reaction system, zinc chloride is used to increase the vitality of fertilized eggs, and fetal bovine serum is used to terminate the digestion reaction of trypsin.

[0028] The fertilized eggs were placed in an incubation bucket with povidone iodine, aerated for 15 minutes, and then removed and washed with clean seawater. The eggs were then placed in an incubation bucket with trypsin, aerated for 30 minutes, and then removed and washed with clean seawater containing 0.5 ppm fetal bovine serum. The treated fertilized eggs were then placed in a pre-prepared indoor pool.

[0029] S2. Strengthen rotifers and collect rotifer eggs:

[0030] A high-concentration nutrient solution is used to enhance the ultrafine Brachionus plicatilis rotifer, wherein the long diameter is less than 140 μm and the short diameter is less than 90 μm. The specific enhancement method is as follows: adding seawater with a salinity of 10‰ to the hatching bucket, adding 2 ppm trichloroisocyanuric acid, and vigorously aerating until there is no residual chlorine for use; adding nutrient mother solution according to the weight of the water in the hatching bucket, the mass ratio of water to nutrient mother solution is 100:1, and the temperature of the hatching bucket is controlled at 31-32°C and the pH is 5.6-6.3; after mixing evenly, the ultrafine Brachionus plicatilis rotifer is added to the hatching bucket for enhancement, using pure oxygen to provide oxygen, the dissolved oxygen is not less than 12 mg / L, and the enhancement is carried out for 12 hours. After the enhancement is completed, the rotifer is fished out and placed in another nutrient mother solution of the same concentration for a second enhancement, and the enhancement time is 12 hours;

[0031] The preparation method of the nutrient mother solution is as follows: 10g / L of Pseudomonas pseudochloris powder, 1g / L of Haematococcus pluvialis powder, 10g / L of Schizochytrium powder, 10g / L of Antarctic krill oil, 1g / L of Liyang brand aquatic special compound premix feed, 2g / L of emulsifier monoglyceride, add purified water, and mix in a homogenizer to form an emulsion.

[0032] During the strengthening process, the ultrafine wrinkled brachium rotifer continuously produces rotifer eggs. After the strengthening is completed, the nutritious rotifer eggs are collected, disinfected with 0.5ppm sodium hypochlorite, cleaned, and placed in aerated clean seawater with a salinity of 10‰ and a temperature of 15°C for standby use. The rotifer eggs are collected in the following manner: the strengthened rotifers are picked up, drained, and deep-sea fish oil with a weight ratio of 10% of the rotifers is added and gently mixed to lubricate and prevent the rotifer eggs from being damaged during the cleaning process; the rotifers are placed in a 200-mesh sieve, and a 300-500-mesh sieve is placed under the sieve to receive the rotifer eggs. The 300-500-mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating. The rotifers are repeatedly rinsed with seawater with a pressure of 0.4mpa until the rotifer eggs detach and flow through the 200-mesh sieve into the 300-500-mesh sieve to collect the rotifer eggs.

[0033] S3, fish flower and metamorphosis early stage indoor cultivation:

[0034] In 20-50m 3Prepare clean seawater with a salinity of 10‰ and a water temperature of 28-32℃ in an indoor pond. Place an aeration head per square meter and add 1×10 6 cfu / m 3 After the Bacillus, put the treated fertilized eggs; after the fry open, add 20ppm of Chlorella in the pond, 1×10 7 cfu / m 3 Lactic acid bacteria; 12 hours after the fry hatch, feed rotifer eggs to facilitate hatching. The final concentration of rotifer eggs in the tank is 10 / mL. Feed rotifer eggs every 8 hours to maintain the final concentration of 10 / mL. Feed continuously for 4 days. The lighting is 2000-3000 lux full-spectrum light, which is on 24 hours uninterruptedly. From the 5th to the 8th day after hatching, feed ultramicroscopic Brachionus plicatilis rotifers with a long diameter of less than 140μm and a short diameter of less than 90μm. Start feeding Artemia nauplii on the 9th day after hatching.

[0035] On the 13th day after hatching, inject 0.5ppm vitamin C and 0.1ppm eugenol, turn off all light sources in the hatching space to maintain a completely dark environment, and use a searchlight with a light intensity greater than 5000lux to induce the fry to gather. The specific method is: set the searchlight to gradual brightness mode, increase the light intensity by 1000lux per minute until it reaches 5000-8000lux, place the searchlight on the water surface, and shine it at a 60° angle into the water surface. After the fry gather, use a scoop to slowly scoop up the fry, place them in a slightly aerated bucket, and transport the fry to the outdoor pond;

[0036] S4, outdoor cultivation in the middle stage of metamorphosis:

[0037] Before stocking the fry into the outdoor pond, the outdoor pond needs to be disinfected and the water quality needs to be kept stable. The disinfection is carried out as follows: a chlorine dioxide generator with electrolysis of seawater and 150-200m 3 / h protein skimmer circulates and disinfects outdoor pond seawater. The circulation process current is 40-80A and the voltage is 2-6V. Water in the pond is continuously extracted for disinfection. The chlorine output of the discharged seawater is 0.1-0.15mg / L. The water retention time in the protein skimmer is not less than 2 minutes. At the discharge end, a waterwheel-type oxygenator is added to push the seawater in the pond and promote the mixing of electrolyzed seawater and the original water in the pond. The daily circulating water volume is 60-80% of the total water volume. Gram-negative bacteria are not higher than 20 cfu / mL, and Gram-positive bacteria are not higher than 50 cfu / mL.

[0038] The fry were gently placed in an outdoor pond and fed with brine shrimp nauplii until they were full; 21 days after hatching, they were fed with copepods until they were full; 35 days after hatching, fully developed fry were obtained.

[0039] The method for raising seedlings of grouper on a large scale proposed by the present invention will be further described below in conjunction with specific embodiments:

[0040] Example 1

[0041] 2.4 kg of fertilized eggs were disinfected and digested, and placed in three ponds for early cultivation. Later, all juveniles were cultivated in one pond. The early cultivation was carried out according to the following steps:

[0042] S1. Prepare a 1000 L incubation tank, inject clean seawater with a salinity of 30‰, vigorously aerate, and add 3 ppm povidone iodine. Prepare another 1000 L incubation tank, inject clean seawater with a salinity of 30‰, vigorously aerate, add 0.5 ppm trypsin, 1 ppm glutathione, 1 ppm ethylenediaminetetraacetic acid, and 0.2 ppm zinc chloride, adjust the pH of the seawater to 8.0, and control the temperature to 32°C.

[0043] The fertilized eggs were placed in an incubation bucket with povidone iodine, aerated for 15 minutes, and then removed and washed with clean seawater. The eggs were then placed in an incubation bucket with trypsin, aerated for 30 minutes, and then removed and washed with clean seawater containing 0.5 ppm fetal bovine serum. The treated fertilized eggs were then placed in a pre-prepared indoor pool.

[0044] S2. Use a high-concentration nutrient solution to strengthen the ultrafine plicatilaginous rotifers, whose major diameter is less than 140 μm and minor diameter is less than 90 μm. The specific strengthening method is as follows: add seawater with a salinity of 10‰ to the hatching bucket, add 2 ppm trichloroisocyanuric acid, and vigorously aerate until there is no residual chlorine; add nutrient mother solution according to the weight of the water in the hatching bucket, the mass ratio of water to nutrient mother solution is 100:1, and the temperature of the hatching bucket is controlled to 32°C and the pH is 5.6; after mixing evenly, add the ultrafine plicatilaginous rotifers to the hatching bucket for strengthening, use pure oxygen to provide oxygen, the dissolved oxygen is 18 mg / L, and strengthen for 12 hours. After strengthening is completed, the rotifers are fished out and placed again in another hatching bucket with nutrient mother solution for secondary strengthening, and the strengthening time is 12 hours;

[0045] The nutrient solution is prepared as follows: 10 g / L of Nannochloropsis algae powder, 1 g / L of Haematococcus pluvialis powder, 10 g / L of Schizochytrium algae powder, 10 g / L of Antarctic krill oil, 1 g / L of Liyang brand aquatic compound premix, and 2 g / L of emulsifier monoglyceride are added to purified water and blended in a homogenizer to form an emulsion.

[0046] During the strengthening process, the ultrafine wrinkled brachium rotifers continuously produce rotifer eggs. After the strengthening is completed, the nutritious rotifer eggs are collected, disinfected with 0.5ppm sodium hypochlorite, cleaned, and placed in aerated clean seawater with a salinity of 10‰ and a temperature of 15°C for standby use. The collection of rotifer eggs is carried out as follows: the strengthened rotifers are picked up, drained, and deep-sea fish oil with a weight ratio of 10% of the rotifers is added and gently mixed to lubricate and prevent the rotifer eggs from being damaged during the cleaning process; the rotifers are placed in a 200-mesh sieve, and a 500-mesh sieve is placed under the sieve to receive the rotifer eggs. The 500-mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating. The rotifers are repeatedly rinsed with seawater with a pressure of 0.4mpa until the rotifer eggs detach and flow into the 500-mesh sieve through the 200-mesh sieve to collect the rotifer eggs.

[0047] S3, at 25m 3 Prepare clean seawater with a salinity of 10‰ and a water temperature of 32℃ in an indoor pond. Place an aeration head per square meter and add 1×10 6 cfu / m 3 After the Bacillus, put the treated fertilized eggs; after the fry open, add 20ppm of Chlorella in the pond, 1×10 7 cfu / m 3 Lactic acid bacteria; 12 hours after the fry hatch, feed rotifer eggs to facilitate hatching. The final concentration of rotifer eggs in the tank is 10 / mL. Feed rotifer eggs every 8 hours to maintain the final concentration of 10 / mL. Feed continuously for 4 days. The light is 3000 lux full-spectrum light, which is on 24 hours uninterruptedly. From the 5th to the 8th day after hatching, feed ultramicroscopic Brachionus plicatilis rotifers with a long diameter of less than 140μm and a short diameter of less than 90μm. Start feeding Artemia nauplii on the 9th day after hatching.

[0048] On the 13th day after hatching, inject 0.5ppm vitamin C and 0.1ppm eugenol, turn off all light sources in the hatching space to maintain a completely dark environment, and use a searchlight with a light intensity of 6000lux to induce the fry to gather. The method is as follows: set the searchlight to gradual brightness mode, increase the light intensity by 1000lux per minute until it reaches 6000lux, place the searchlight on the water surface, and shine it at a 60° angle into the water surface. After the fry gather, use a scoop to slowly scoop up the fry, place them in a slightly aerated bucket, and transport the fry to the outdoor pond;

[0049] S4. Before releasing the fry into the outdoor pond, the outdoor pond must be disinfected and the water quality must be kept stable. The disinfection is carried out as follows: a chlorine dioxide generator with electrolysis of seawater and 200m 3A protein skimmer with a flow rate of 60A / h circulates and disinfects outdoor pond seawater to maintain a low bacterial content. The circulation process current is 60A and the voltage is 5V. Water in the pond is continuously extracted for disinfection. The chlorine output of the discharged seawater is 0.15mg / L. The water retention time in the protein skimmer is 2 minutes. At the discharge end, a waterwheel-type oxygenator is added to push the seawater in the pond and promote the mixing of electrolyzed seawater and the original water in the pond. The daily circulating water volume is 60-80% of the total water volume. The Gram-negative bacteria content is no more than 8 cfu / mL, and the Gram-positive bacteria content is no more than 12 cfu / mL.

[0050] The fry were gently placed in an outdoor pond and fed with brine shrimp nauplii until they were full; 21 days after hatching, they were fed with copepods until they were full; 35 days after hatching, fully developed fry were obtained.

[0051] In particular, to illustrate the advantages of the seedling raising method proposed in this embodiment, three ponds were used to raise seedlings using the traditional seedling raising method. Each pond was stocked with 0.8 kg of fertilized eggs of grouper. The traditional seedling raising method was carried out as follows: seawater was disinfected, 3×10 yeast was added to the pond, and 10 9 cfu / mu, fish meal 10ppm, Bacillus 1×10 9 cfu / mu, EM bacteria 1×10 9 cfu / mu, cultivate natural protozoa in the pond, build a hatching bag after the water body stabilizes, put the fish eggs in it, open the bag and put it into the pond, feed the nauplii of Cyclops after 12 days, feed Cyclops after 20 days, and develop for 35 days to obtain the juvenile fish that have completed metamorphosis.

[0052] The number of 3cm fry, survival rate, and number of fry produced per kilogram of eggs under the two fry rearing methods were calculated. The specific results are shown in Table 1. The hatching rate is calculated as the ratio of the number of fry hatched to the number of fertilized eggs. The number of fry is the number of fry about 3cm after the grouper fry metamorphosis is completed. The survival rate is the ratio of the number of fry about 3cm to the number of fry hatched. According to statistics, there are 1.6 million fry per kilogram of fertilized eggs.

[0053] Table 1 Seedling cultivation results of Example 1 and traditional method

[0054]

[0055] Example 2

[0056] 2.4 kg of fertilized eggs were disinfected and digested, and placed in three ponds for early cultivation. Later, all juveniles were cultivated in one pond. The early cultivation was carried out according to the following steps:

[0057] S1. Prepare a 1000L incubation tank, inject 800L of clean seawater with a salinity of 30‰, vigorously aerate, and add 3ppm povidone-iodine. Prepare another 1000L incubation tank, inject 800L of clean seawater with a salinity of 30‰, vigorously aerate, add 0.5ppm trypsin, 1ppm glutathione, 1ppm ethylenediaminetetraacetic acid, and 0.2ppm zinc chloride, adjust the pH of the seawater to 8.0, and control the temperature to 32°C.

[0058] The fertilized eggs were placed in an incubation bucket with povidone iodine, aerated for 15 minutes, and then removed and washed with clean seawater. The eggs were then placed in an incubation bucket with trypsin, aerated for 30 minutes, and then removed and washed with clean seawater containing 0.5 ppm fetal bovine serum. The treated fertilized eggs were then placed in a pre-prepared indoor pool.

[0059] S2. Use a high-concentration nutrient solution to strengthen the ultrafine plicatilaginous rotifers, whose major diameter is less than 140 μm and minor diameter is less than 90 μm. The specific strengthening method is as follows: add seawater with a salinity of 10‰ to the hatching bucket, add 2 ppm trichloroisocyanuric acid, and vigorously aerate until there is no residual chlorine for standby use; add nutrient mother solution according to the weight of the water in the hatching bucket, the mass ratio of water to nutrient mother solution is 100:1, and the temperature of the hatching bucket is controlled to 32°C and the pH is 6.0; after mixing evenly, add the ultrafine plicatilaginous rotifers to the hatching bucket for strengthening, use pure oxygen to provide oxygen, the dissolved oxygen is not less than 12 mg / L, strengthen for 12 hours, and after strengthening is completed, remove the rotifers and put them into another hatching bucket with nutrient mother solution for secondary strengthening, and the strengthening time is 12 hours;

[0060] The nutrient solution is prepared as follows: 10 g / L of Nannochloropsis algae powder, 1 g / L of Haematococcus pluvialis powder, 10 g / L of Schizochytrium algae powder, 10 g / L of Antarctic krill oil, 1 g / L of Liyang brand aquatic compound premix, and 2 g / L of emulsifier monoglyceride are added to purified water and blended in a homogenizer to form an emulsion.

[0061] During the strengthening process, the ultrafine wrinkled brachium rotifers continuously produce rotifer eggs. After the strengthening is completed, the nutritious rotifer eggs are collected, disinfected with 0.5ppm sodium hypochlorite, cleaned, and placed in aerated clean seawater with a salinity of 10‰ and a temperature of 15°C for standby use. The collection of rotifer eggs is carried out as follows: the strengthened rotifers are picked up, drained, and deep-sea fish oil with a weight ratio of 10% of the rotifers is added and gently mixed to lubricate and prevent the rotifer eggs from being damaged during the cleaning process; the rotifers are placed in a 200-mesh sieve, and a 500-mesh sieve is placed under the sieve to receive the rotifer eggs. The 500-mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating. The rotifers are repeatedly rinsed with seawater with a pressure of 0.4mpa until the rotifer eggs detach and flow into the 500-mesh sieve through the 200-mesh sieve to collect the rotifer eggs.

[0062] S3, at 25m 3 Prepare clean seawater with a salinity of 10‰ and a water temperature of 32℃ in an indoor pond. Place an aeration head per square meter and add 1×10 6 cfu / m 3 After the Bacillus, put the treated fertilized eggs; after the fry open, add 20ppm of Chlorella in the pond, 1×10 7 cfu / m 3 Lactic acid bacteria; 12 hours after the fry hatch, feed rotifer eggs to facilitate hatching. The final concentration of rotifer eggs in the tank is 10 / mL. Feed rotifer eggs every 8 hours to maintain the final concentration of 10 / mL. Feed continuously for 4 days. The light is 3000 lux full-spectrum light, which is on 24 hours uninterruptedly. From the 5th to the 8th day after hatching, feed ultramicroscopic Brachionus plicatilis rotifers with a long diameter of less than 140μm and a short diameter of less than 90μm. Start feeding Artemia nauplii on the 9th day after hatching.

[0063] On the 13th day after hatching, inject 0.5ppm vitamin C and 0.1ppm eugenol, turn off all light sources in the hatching space to maintain a completely dark environment, and use a searchlight with a light intensity of 6000lux to induce the fry to gather. The method is as follows: set the searchlight to gradual brightness mode, increase the light intensity by 1000lux per minute until it reaches 6000lux, place the searchlight on the water surface, and shine it at a 60° angle into the water surface. After the fry gather, use a scoop to slowly scoop up the fry, place them in a slightly aerated bucket, and transport the fry to the outdoor pond;

[0064] S4. Before releasing the fry into the outdoor pond, the outdoor pond must be disinfected and the water quality must be kept stable. The disinfection is carried out as follows: a chlorine dioxide generator with electrolysis of seawater and 200m 3A protein skimmer with a flow rate of 80A / h circulates and disinfects outdoor pond seawater to maintain a low bacterial content. The circulation process current is 80A and the voltage is 6V. Water in the pond is continuously extracted for disinfection. The chlorine output of the discharged seawater is 0.15mg / L. The water retention time in the protein skimmer is 2 minutes. At the discharge end, a waterwheel-type oxygenator is added to push the seawater in the pond and promote the mixing of electrolyzed seawater and the original water in the pond. The daily circulating water volume is 60% of the total water volume. The Gram-negative bacteria content is no more than 6 cfu / mL, and the Gram-positive bacteria content is no more than 9 cfu / mL.

[0065] The fry were gently placed in an outdoor pond and fed with brine shrimp nauplii until they were full; 21 days after hatching, they were fed with copepods until they were full; 35 days after hatching, fully developed fry were obtained.

[0066] In particular, to illustrate the advantages of the seedling raising method proposed in this embodiment, three ponds were used to raise seedlings using the traditional seedling raising method. 0.2 kg of fertilized eggs of grouper were placed in each pond. The traditional seedling raising method was carried out as follows: the seawater was disinfected, the eggs were placed in the seawater, and after opening, 1×10 7 cfu / m 3 and rotifers 500 million / m 3 After 12 days, the fish were fed with nauplii of Cyclops, and after 20 days, they were fed with Cyclops. After 35 days of development, the juvenile fish that had completed metamorphosis were obtained.

[0067] The number of 3 cm fry, survival rate, and number of fry produced per kilogram of eggs under the two fry rearing methods were calculated. The specific results are shown in Table 2. The hatching rate is calculated as the ratio of the number of fry hatched to the number of fertilized eggs. The number of fry is the number of fry about 3 cm after the grouper fry metamorphosis is completed. The survival rate is the ratio of the number of fry about 3 cm to the number of fry hatched. According to statistics, there are 1.6 million fry per kilogram of fertilized eggs.

[0068] Table 2 Seedling cultivation results of Example 2 and traditional method

[0069]

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for large-scale breeding of saddleback grouper, characterized in that: The steps include: S1. digesting the fertilized eggs of the saddle grouper to facilitate the rupture of the membrane; The digestion treatment is performed according to the following steps: injecting clean seawater with a salinity of 25-33‰ into a 500-1000L incubation bucket, vigorously aerating, and adding 3ppm povidone iodine; injecting clean seawater with a salinity of 25-33‰ into another 500-1000L incubation bucket, vigorously aerating, adding 0.5ppm trypsin, 1ppm glutathione, 1ppm ethylenediaminetetraacetic acid, and 0.2ppm zinc chloride, and adjusting the pH of the seawater to 7.8-8.5 and controlling the temperature to 28-32°C; The fertilized eggs were placed in an incubation bucket with povidone iodine, aerated for 15 minutes, and then removed and washed with clean seawater. The eggs were then placed in an incubation bucket with trypsin, aerated for 30 minutes, and then removed and washed with clean seawater containing 0.5 ppm fetal bovine serum. The treated fertilized eggs were then placed in a pre-prepared indoor pool. S2, using nutrient solution to enhance the ultrafine Brachionus plicatilis rotifer, collecting rotifer eggs and feeding them to the hatched fry; The enhancement of Brachionus plicatilis ultrafine rotifers is carried out as follows: adding seawater with a salinity of 10‰ to an incubation bucket, adding 2ppm trichloroisocyanuric acid, and vigorously aerating until there is no residual chlorine for use; adding nutrient solution according to the weight of the water in the incubation bucket, with a mass ratio of water to nutrient solution of 100:1, and controlling the temperature of the incubation bucket to be 31-32°C and the pH to be 5.6-6.3; after uniform mixing, adding the Brachionus plicatilis ultrafine rotifers to the incubation bucket for enhancement, using pure oxygen to provide oxygen, with dissolved oxygen not less than 12mg / L, and enhancing for 12 hours. After the enhancement is completed, the rotifers are removed and placed in another incubation bucket with nutrient solution for a second enhancement, and the enhancement time is 12 hours. The nutrient mother solution is prepared as follows: 10g / L of Nannochloropsis algae powder, 1g / L of Haematococcus pluvialis powder, 10g / L of Schizochytrium algae powder, 10g / L of Antarctic krill oil, 1g / L of Liyang brand aquatic special compound premix feed, and 2g / L of emulsifier monoglyceride are added to purified water and blended in a homogenizer to form an emulsion; S3, fish flower and metamorphosis early stage indoor cultivation: In 20-50m 3 Prepare clean seawater with a salinity of 10‰ and a water temperature of 28-32℃ in an indoor pond. Place an aeration head per square meter and add 1×10 6 cfu / m 3 After the Bacillus, put the treated fertilized eggs; after the fry open, add 20ppm of Chlorella in the pond, 1×10 7 cfu / m 3 Lactic acid bacteria; 12 hours after the fry hatch, feed rotifer eggs to facilitate hatching. The final concentration of rotifer eggs in the tank is 10 / mL. Feed rotifer eggs every 8 hours to maintain the final concentration of 10 / mL. Feed continuously for 4 days. The lighting is 2000-3000 lux full-spectrum light, which is on 24 hours uninterruptedly. From the 5th to the 8th day after hatching, feed ultramicroscopic Brachionus plicatilis rotifers with a long diameter of less than 140μm and a short diameter of less than 90μm. Start feeding Artemia nauplii on the 9th day after hatching. On the 13th day after hatching, inject 0.5ppm vitamin C and 0.1ppm eugenol, turn off all light sources in the hatching space to maintain a completely dark environment, use a searchlight with a light intensity greater than 5000lux to induce the fry to gather, collect the fry, and transport them to the outdoor pond; S4, outdoor cultivation in the middle stage of metamorphosis: After the outdoor pond is disinfected, the fry are placed in the outdoor pond and fed with brine shrimp nauplii until they are full; 21 days after hatching, they are fed with copepods until they are full; 35 days after hatching, fully developed fry are obtained.

2. The seedling raising method according to claim 1, wherein In step S2, the rotifer eggs are collected as follows: the strengthened rotifers are picked up, drained, and deep-sea fish oil is added at 10% of the weight of the rotifers; the rotifers are placed in a 200-mesh sieve, and a 300-500-mesh sieve is placed under the sieve to receive the rotifer eggs. The 300-500-mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating. The rotifers are repeatedly rinsed with seawater at a pressure of 0.4 MPa until the rotifer eggs are detached and flow through the 200-mesh sieve into the 300-500-mesh sieve, thereby realizing the collection of the rotifer eggs; the collected rotifer eggs need to be disinfected with 0.5 ppm sodium hypochlorite, cleaned, and placed in aerated clean seawater with a salinity of 10‰ and a temperature of 15°C for standby use.

3. The seedling raising method according to claim 1, wherein In step S4, the outdoor pond disinfection treatment is carried out as follows: a seawater electrolysis chlorine dioxide generator and 150-200m 3 / h protein skimmer is used to circulate and disinfect outdoor pond seawater. The circulation process current is 40-80A and the voltage is 2-6V. Water in the pond is continuously extracted for disinfection. The chlorine production of the discharged seawater is 0.1-0.15mg / L. The water residence time in the protein skimmer is not less than 2min. At the discharge end, a waterwheel-type oxygenator is added to push the seawater in the pond and promote the mixing of electrolyzed seawater and the original water in the pond. The daily circulating water volume is 60-80% of the total water volume. Gram-negative bacteria are not higher than 20 cfu / mL, and Gram-positive bacteria are not higher than 50 cfu / mL.

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