Large-scale epinephelus lanceolatus breeding method

Abstract

The invention provides a large-scale epinephelus lanceolatus breeding method, and relates to the technical field of epinephelus lanceolatus breeding, the method comprises the steps of fertilized egg digestion treatment and indoor and outdoor relay breeding, and the fertilized eggs are subjected to digestion treatment, so that membrane rupture of fish flowers can be facilitated; in the indoor breeding process, the calamus eggs obtained after fry strengthening are fed, more nutrient substances can be provided for the fry, and the fry can open the mouth easily; fish flowers are cultured indoors when the bodies of the fish flowers are weak in the early metamorphosis stage, the fish flowers are cultured in an outdoor pond after having certain resistance, the resistance of the fish fries can be effectively improved, in addition, during outdoor culture, the fish fries can be prevented from being affected by pathogenic microorganisms while the water body is continuously disinfected and ammonia nitrogen is removed through an electrolytic seawater chlorine dioxide generator, and the fish fries are effectively prevented from being damaged. Under the action, the seedling survival rate can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of grouper breeding, and particularly relates to a method for large-scale seedling raising of Epinephelus lanceolatus. Background Art

[0002] Groupers are a type of carnivorous reef-dwelling fish living in tropical and subtropical waters, belonging to the order Perciformes, family Serranidae. The family Serranidae contains 16 genera and 165 species, with rich phenotypes. They are famous for their delicious and nutritious meat and are known as "sea chicken meat". They are important edible fish in the southern coastal areas of China. Guangdong Province, Hainan Province, and Fujian Province have always been important seedling supply and commercial fish farming areas for groupers. According to the Fisheries Statistical Yearbook of China, the annual output of groupers in China has reached 241,000 tons, ranking fourth in the output of Chinese marine fish. Groupers are important aquaculture economic fish in China.

[0003] Epinephelus lanceolatus, also known as the giant grouper, is the largest species in the family Serranidae, with a maximum weight of up to 400 kg and a body length of up to 2.7 m. Due to its growth advantages, Epinephelus lanceolatus is an important male parent in grouper cross-breeding. Tiger grouper (Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂), Marbled grouper (Epinephelus moara♀×Epinephelus lanceolatus♂), and Humpback grouper (Cromileptes altivelis♀×Epinephelus lanceolatus♂) all use Epinephelus lanceolatus as the male parent. Tiger grouper is an important cultured grouper species in China, with a market share of about 70%. Epinephelus lanceolatus itself has delicious meat and elastic and smooth fish skin, and is a delicious seafood delicacy. However, due to the small egg diameter and poor quality of Epinephelus lanceolatus, the small mouth diameter of fry after hatching, and the problem of low seedling survival rate has not been solved, and it is impossible to stably obtain a large number of high-quality seedlings.

[0004] In view of this, it is necessary to design an improved method for large-scale seedling raising of Epinephelus lanceolatus to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for large-scale seedling raising of Epinephelus lanceolatus.

[0006] To achieve the above invention purpose, the present invention provides a method for large-scale seedling raising of Epinephelus lanceolatus, including the following steps:

[0007] S1. Carry out digestion treatment on the fertilized eggs to facilitate the hatching of fry;

[0008] S2. Strengthen Brachionus plicatilis with nutrient solution, collect rotifer eggs and feed them to the fry after hatching;

[0009] S3. Indoor culture of fry and pre-metamorphosis stage:

[0010] In an indoor pond of 20 - 50 m 3 Prepare clean seawater with a salinity of 10‰, a water temperature of 28 - 32°C. Place one aeration head per square meter. Add 1×10 6 cfu / m 3 Bacillus spores into the pond, and then put in the treated fertilized eggs. After the fry start to feed, add 20 ppm Chlorella vulgaris and 1×10 7 cfu / m 3 Lactobacillus into the pond. 12 hours after the fry start to feed, feed rotifer eggs to facilitate the fry's feeding. The final concentration of rotifer eggs in the water tank is 10 eggs / mL. Feed rotifer eggs every 8 hours to maintain the final concentration of 10 eggs / mL, and continuously feed for 4 days. The light is a 2000 - 3000 lux full-spectrum light, which is turned on continuously for 24 hours. From the 5th to the 8th day after the fry start to feed, feed ultra-small Brachionus plicatilis, with a major axis less than 140 μm and a minor axis less than 90 μm. Start feeding nauplii of Artemia salina on the 9th day after the fry start to feed;

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

[0012] S4. Outdoor cultivation during the mid-metamorphosis stage:

[0013] After disinfecting the outdoor pond, put the fry into the outdoor pond and feed them nauplii of Artemia salina until they are full. 21 days after hatching, feed copepods until they are full. 35 days after hatching, obtain fully developed juvenile fish.

[0014] Preferably, in step S2, the enrichment of ultra-small Brachionus plicatilis is carried out as follows: Add seawater with a salinity of 10‰ to the hatching bucket, add 2 ppm trichloroisocyanuric acid, and aerate vigorously until there is no residual chlorine, then set aside for use. According to the weight of the water body in the hatching bucket, add the nutrient mother liquor. The mass ratio of the water body to the nutrient mother liquor is 100:1. Control the temperature of the hatching bucket at 31 - 32°C and the pH at 5.6 - 6.3. After mixing evenly, add ultra-small Brachionus plicatilis to the hatching bucket for enrichment, provide oxygen with pure oxygen, and the dissolved oxygen is not less than 12 mg / L. Enrich for 12 hours. After the enrichment is completed, fish out the rotifers and put them into another hatching bucket with nutrient mother liquor for secondary enrichment, and the enrichment time is 12 hours.

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

[0016] Preferably, in step S2, the collection of rotifer eggs is carried out as follows: Lift the enhanced rotifers, drain the water, and add deep-sea fish oil accounting for 10% of the weight of the rotifers; Place the rotifers in a 200-mesh sieve, and place a 300-500-mesh sieve under the sieve to collect the rotifer eggs. The 300-500-mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating. Use seawater with a pressure of 0.4 mpa to repeatedly rinse the rotifers until the rotifer eggs are detached and flow through the 200-mesh sieve into the 300-500-mesh sieve, thus realizing the collection of rotifer eggs; The collected rotifer eggs need to be disinfected with 0.5 ppm of sodium hypochlorite, cleaned, and placed in clean seawater with an aerated salinity of 10‰ and a temperature of 15°C for standby.

[0017] Preferably, in step S1, the digestion treatment is carried out according to the following steps: Inject clean seawater with a salinity of 25-33‰ into an incubation barrel with a volume of 500-1000 L, vigorously aerate, and add 3 ppm of povidone iodine; Inject clean seawater with a salinity of 25-33‰ into another incubation barrel with a volume of 500-1000 L. After vigorous aeration, add 0.5 ppm of trypsin, 1 ppm of glutathione, 1 ppm of ethylenediaminetetraacetic acid, 0.2 ppm of zinc chloride, and adjust the pH of the seawater to 7.8-8.5, and control the temperature at 28-32°C;

[0018] Put the fertilized eggs into the incubation barrel with povidone iodine. After aerating for 15 minutes, fish out the fertilized eggs and wash them with clean seawater. Then put them into the incubation barrel with trypsin. After aerating for 30 minutes, fish out the fertilized eggs and wash them with clean seawater containing 0.5 ppm of fetal bovine serum. Then put the treated fertilized eggs into a pre-prepared indoor water pool.

[0019] Preferably, in step S4, the disinfection treatment of the outdoor pond is carried out as follows: Through an electrolytic seawater chlorine dioxide generator and a protein skimmer with a flow rate of 150-200 m 3 / h, circulate and disinfect the seawater in the outdoor pond. The current during the circulation process is 40-80 A, the voltage is 2-6 V. Continuously extract the water body in the pond for disinfection. The chlorine production of the discharged seawater is 0.1-0.15 mg / L. The residence time of the water body in the protein skimmer is not less than 2 minutes. At the discharge end, add a waterwheel aerator to push the seawater in the pond to promote the mixing of the electrolytic seawater and the original water body in the pond. The daily circulation water volume is 60-80% of the total water body. The number of Gram-negative bacteria is not higher than 20 cfu / mL, and the number of Gram-positive bacteria is not higher than 50 cfu / mL.

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

[0021] The large-scale breeding method of Epinephelus lanceolatus provided by the present invention includes the digestion treatment of fertilized eggs and relay breeding indoors and outdoors. By carrying out the digestion treatment on the fertilized eggs, it is beneficial for the fish fry to break through the membrane. During the indoor cultivation process, by feeding the rotifer eggs obtained after strengthening the fry, more nutrients can be provided for the fry, which is beneficial for the fry to start feeding. By culturing indoors when the fish fry and the pre-metamorphosis stage are weak in constitution and transferring them to the outdoor pond for cultivation after having a certain resistance, the resistance of the fry can be effectively improved. In addition, during the outdoor cultivation, by using an electrolytic seawater chlorine dioxide generator to continuously disinfect the water body, while removing ammonia nitrogen, it is possible to prevent the fry from being affected by pathogenic microorganisms. Under the above actions, the breeding survival rate can be improved. Detailed implementation manners

[0022] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to specific embodiments.

[0023] Here, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the text, while other details less related to the present invention are omitted.

[0024] In addition, it should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

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

[0026] S1. Carry out digestion treatment on the fertilized eggs to facilitate the fish fry to break through the membrane:

[0027] Inject clean seawater with a salinity of 25-33‰ into an incubation barrel with a volume of 500-1000L, aerate vigorously, and add 3ppm povidone iodine; inject clean seawater with a salinity of 25-33‰ into another incubation barrel with a volume of 500-1000L. After vigorous aeration, add 0.5ppm trypsin, 1ppm glutathione, 1ppm ethylenediaminetetraacetic acid, 0.2ppm zinc chloride, and adjust the pH of the seawater to 7.8-8.5, and control the temperature at 28-32°C. In this step, povidone iodine is used for disinfection, the role of trypsin is to digest the eggshell, glutathione is used to deal with oxidation 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 viability of fertilized eggs, and fetal bovine serum is used to terminate the digestion reaction of trypsin.

[0028] Put the fertilized eggs into an incubation bucket with povidone iodine added. After aerating for 15 minutes, take out the fertilized eggs and wash them with clean seawater. Then put them into an incubation bucket with trypsin added. After aerating for 30 minutes, take out the fertilized eggs and wash them with clean seawater containing 0.5 ppm fetal bovine serum. Then put the treated fertilized eggs into a pre-prepared indoor water tank;

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

[0030] Strengthen the ultra-micro Brachionus plicatilis with a high-concentration nutrient solution. Its major axis is less than 140 μm and its minor axis is less than 90 μm. The specific strengthening method is as follows: Add seawater with a salinity of 10‰ into the incubation bucket, add 2 ppm trichloroisocyanuric acid, and aerate vigorously until there is no residual chlorine, then set aside; According to the weight of the water body in the incubation bucket, add the nutrient mother liquor. The mass ratio of the water body to the nutrient mother liquor is 100:1. Control the temperature of the incubation bucket at 31 - 32 °C and the pH at 5.6 - 6.3; After mixing evenly, add the ultra-micro Brachionus plicatilis into the incubation bucket for strengthening. Provide oxygen with pure oxygen, and the dissolved oxygen is not less than 12 mg / L. Strengthen for 12 hours. After the strengthening is completed, take out the rotifers and put them into another nutrient mother liquor with the same concentration for secondary strengthening, and the strengthening time is 12 hours;

[0031] Among them, the preparation method of the nutrient mother liquor is as follows: 10 g / L Nannochloropsis oculata powder, 1 g / L Haematococcus pluvialis powder, 10 g / L Schizochytrium sp. powder, 10 g / L Antarctic krill oil, 1 g / L aquatic special compound premix feed of Liyang brand, 2 g / L emulsifier monoglyceride, add pure water, and homogenize in a homogenizer to form an emulsion.

[0032] During the strengthening process, the ultra-micro Brachionus plicatilis continuously produces rotifer eggs. After the strengthening is completed, collect the nutrient-rich rotifer eggs, disinfect them with 0.5 ppm sodium hypochlorite, wash them clean, and put them into aerated clean seawater with a salinity of 10‰ and a temperature of 15 °C for standby. The collection of rotifer eggs is carried out as follows: Lift the strengthened rotifers, drain the water, add 10% of the weight of the rotifers of deep-sea fish oil, and mix gently to lubricate and prevent damage to the rotifer eggs during the cleaning process; Put the rotifers into a 200-mesh sieve, and place a 300 - 500-mesh sieve under the sieve to pick up the rotifer eggs. The 300 - 500-mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating. Use seawater with a pressure of 0.4 mpa to repeatedly wash the rotifers until the rotifer eggs break away and flow through the 200-mesh sieve into the 300 - 500-mesh sieve, then the collection of rotifer eggs can be achieved;

[0033] S3. Indoor culture during the fry and pre-metamorphosis stage:

[0034] At 20 - 50 m 3Prepare clean seawater with a salinity of 10‰ in an indoor pond, with a water temperature of 28 - 32°C. Place one aeration head per square meter, and add 1×10 6 cfu / m 3 Bacillus spores into the pond, and then put in the treated fertilized eggs. After the fry start to feed, add 20 ppm Chlorella vulgaris and 1×10 7 cfu / m 3 Lactic acid bacteria into the pond. 12 hours after the fry start to feed, feed rotifer eggs to facilitate the fry's feeding. The final concentration of rotifer eggs in the pool is 10 eggs / mL, and feed rotifer eggs every 8 hours to maintain the final concentration of 10 eggs / mL for 4 consecutive days. The light is a full-spectrum light of 2000 - 3000 lux and is turned on continuously for 24 hours. From the 5th to the 8th day after the fry start to feed, feed ultra-small Brachionus plicatilis with a major axis less than 140 μm and a minor axis less than 90 μm. Start feeding nauplii of Artemia salina on the 9th day after the fry start to feed;

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

[0036] S4. Outdoor cultivation during the mid-metamorphosis stage:

[0037] Before putting the fry into the outdoor pond, it is necessary to disinfect the outdoor pond and maintain the water quality stability. The disinfection treatment is carried out as follows: Circulate and disinfect the seawater in the outdoor pond through an electrolytic seawater chlorine dioxide generator and a protein skimmer with a flow rate of 150 - 200 m 3 / h. The current during the circulation process is 40 - 80 A, and the voltage is 2 - 6 V. Continuously pump the water in the pond for disinfection. The chlorine production of the discharged seawater is 0.1 - 0.15 mg / L. The residence time of the water body in the protein skimmer is not less than 2 minutes. At the discharge end, add a waterwheel aerator to push the seawater in the pond and promote the mixing of the electrolyzed seawater and the original water body in the pond. The daily circulation water volume is 60 - 80% of the total water volume. The number of Gram-negative bacteria is not higher than 20 cfu / mL, and the number of Gram-positive bacteria is not higher than 50 cfu / mL;

[0038] Gently put the fry into the outdoor pond and feed them nauplii of Artemia salina until they are full. 21 days after hatching, feed copepods until they are full. 35 days after hatching, obtain fully developed juvenile fish.

[0039] The following further illustrates the large-scale breeding method of Epinephelus lanceolatus proposed by the present invention in combination with specific embodiments:

[0040] Example 1

[0041] Disinfect and decompose 2.4 kg of fertilized eggs, and place them in 3 ponds for early cultivation respectively. Later, cultivate all the fry in one pond. The early cultivation is carried out according to the following steps:

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

[0043] Put the fertilized eggs into the incubation barrel with povidone iodine, fish out the fertilized eggs after aeration for 15 minutes, wash them with clean seawater, then put them into the incubation barrel with trypsin, fish out the fertilized eggs after aeration for 30 minutes, and wash them with clean seawater containing 0.5 ppm of fetal bovine serum. Then put the treated fertilized eggs into the indoor water tank prepared in advance;

[0044] S2. Strengthen the ultra-small Brachionus plicatilis with a high-concentration nutrient solution, whose major axis is less than 140 μm and minor axis is less than 90 μm. The specific strengthening method is as follows: Add seawater with a salinity of 10‰ to the incubation barrel, add 2 ppm of trichloroisocyanuric acid, aerate vigorously until there is no residual chlorine, and then set aside; according to the weight of the water body in the incubation barrel, add the nutrient mother liquor, and the mass ratio of the water body to the nutrient mother liquor is 100:1. Control the temperature of the incubation barrel at 32°C and the pH at 5.6; after mixing evenly, add the ultra-small Brachionus plicatilis to the incubation barrel for strengthening, provide oxygen with pure oxygen, and the dissolved oxygen is 18 mg / L. Strengthen for 12 hours. After the strengthening is completed, fish out the rotifers and put them into another incubation barrel with the nutrient mother liquor for secondary strengthening, and the strengthening time is 12 hours;

[0045] Among them, the preparation method of the nutrient mother liquor is as follows: 10 g / L of Nannochloropsis oculata powder, 1 g / L of Haematococcus pluvialis powder, 10 g / L of Schizochytrium sp. powder, 10 g / L of Antarctic krill oil, 1 g / L of special compound premix feed for aquatic products of Liyang brand, 2 g / L of emulsifier monoglyceride, add pure water, and homogenize in a homogenizer to form an emulsion;

[0046] During the enrichment process, the ultra-microfolded Brachionus rotundiformis continuously produces rotifer eggs. After the enrichment is completed, the nutrient-rich rotifer eggs are collected, disinfected with 0.5 ppm sodium hypochlorite, washed clean, and placed in clean aerated seawater with a salinity of 10‰ and a temperature of 15°C for standby. The collection of rotifer eggs is carried out as follows: The enriched rotifers are fished out, drained of water, and 10% of the weight of the rotifers in deep-sea fish oil is added and gently mixed to lubricate and prevent damage to the rotifer eggs during the cleaning process; the rotifers are placed in a 200-mesh sieve, and a 500-mesh sieve is placed below the sieve to collect the rotifer eggs. The 500-mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating. Seawater with a pressure of 0.4 mpa is used to repeatedly rinse the rotifers until the rotifer eggs break away and flow through the 200-mesh sieve into the 500-mesh sieve, and the collection of rotifer eggs can be achieved;

[0047] S3. Prepare clean seawater with a salinity of 10‰ in an indoor pond of 25 m 3 at a water temperature of 32°C. Place one aeration head per square meter, and add 1×10 6 cfu / m 3 Bacillus spores into the pond, and then put the treated fertilized eggs; after the fry start to feed, add 20 ppm Chlorella vulgaris and 1×10 7 cfu / m 3 Lactic acid bacteria into the pond; 12 hours after the fry start to feed, feed rotifer eggs to facilitate the fry to start feeding. The final concentration of rotifer eggs in the water tank is 10 eggs / mL, and the rotifer eggs are fed once every 8 hours to maintain the final concentration of 10 eggs / mL for 4 consecutive days. The light is a 3000 lux full-spectrum light, which is turned on continuously for 24 hours; from the 5th to the 8th day after the fry start to feed, feed ultra-microfolded Brachionus rotundiformis with a major axis less than 140 μm and a minor axis less than 90 μm. On the 9th day after the fry start to feed, start feeding Artemia nauplii;

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

[0049] S4. Before putting the fry into the outdoor pond, the outdoor pond needs to be disinfected and the water quality needs to be maintained stable. The disinfection treatment is carried out according to the following method: Through an electrolytic seawater chlorine dioxide generator and 200 m 3A protein separator with a capacity of [X] L / h circulates and disinfects the seawater in the outdoor pond, keeping the bacterial content at a low level. During the circulation process, the current is 60 A and the voltage is 5 V. The water in the pond is continuously pumped for disinfection. The chlorine production of the discharged seawater is 0.15 mg / L. The residence time of the water in the protein separator is 2 min. At the discharge end, a waterwheel aerator is added to push the seawater in the pond and promote the mixing of the electrolyzed seawater and the original water in the pond. The daily circulation volume is 60 - 80% of the total water volume. The number of Gram-negative bacteria is not higher than 8 cfu / mL, and the number of Gram-positive bacteria is not higher than 12 cfu / mL.

[0050] Gently place the fry into the outdoor pond and feed them with nauplii of Artemia until they are full. 21 days after hatching, feed them with copepods until they are full. 35 days after hatching, fully developed juvenile fish are obtained.

[0051] Specifically, to illustrate the advantages of the proposed fry rearing method in this embodiment, traditional fry rearing methods are used in 3 ponds respectively. 0.8 kg of Epinephelus lanceolatus fertilized eggs are put into each pond. The traditional fry rearing method is carried out as follows: Disinfect the seawater, add 3×10 9 cfu / mu of yeast, 10 ppm of fish meal, 1×10 9 cfu / mu of Bacillus sp., 1×10 9 cfu / mu of EM bacteria in the pond, cultivate natural protozoa in the pond. After the water body is stable, set up hatching bags, put the fish eggs into them, and put them into the pond after opening. After 12 days, feed them with nauplii of Cyclops, and after 20 days, feed them with Cyclops. After 35 days of development, juvenile fish that have completed metamorphosis are obtained.

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

[0053] Table 1 Fry rearing results of Example 1 and traditional method

[0054]

[0055] Example 2

[0056] Disinfect and digest 2.4 kg of fertilized eggs, and put them into 3 ponds respectively for early cultivation. Later, all juvenile fish are cultivated in one pond. The early cultivation is carried out according to the following steps:

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

[0058] Put the fertilized eggs into the incubation bucket with povidone iodine added. After aerating for 15 minutes, fish out the fertilized eggs and wash them with clean seawater. Then put them into the incubation bucket with trypsin added. After aerating for 30 minutes, fish out the fertilized eggs and wash them with clean seawater containing 0.5 ppm of fetal bovine serum. Then put the treated fertilized eggs into the indoor water pool prepared in advance;

[0059] S2. Strengthen the ultra - micro Brachionus plicatilis with a high - concentration nutrient solution. Its major axis is less than 140 μm and its minor axis is less than 90 μm. The specific strengthening method is as follows: Add seawater with a salinity of 10‰ to the incubation bucket, add 2 ppm of trichloroisocyanuric acid, aerate vigorously until there is no residual chlorine and then set aside; according to the weight of the water body in the incubation bucket, add the nutrient mother liquor, and the mass ratio of the water body to the nutrient mother liquor is 100:1. Control the temperature of the incubation bucket at 32 °C and the pH at 6.0; after mixing evenly, add the ultra - micro Brachionus plicatilis into the incubation bucket for strengthening, provide oxygen with pure oxygen, and the dissolved oxygen is not less than 12 mg / L. Strengthen for 12 h. After the strengthening is completed, fish out the rotifers and put them into another incubation bucket with the nutrient mother liquor added for secondary strengthening, and the strengthening time is 12 h;

[0060] Among them, the preparation method of the nutrient mother liquor is as follows: 10 g / L of Nannochloropsis oculata powder, 1 g / L of Haematococcus pluvialis powder, 10 g / L of Schizochytrium sp. powder, 10 g / L of Antarctic krill oil, 1 g / L of a special compound premix feed for aquatic products of the Liyang brand, 2 g / L of emulsifier monoglyceride, add pure water, and homogenize in a homogenizer to form an emulsion;

[0061] During the enrichment process, the ultra-microfolded Brachionus rotundiformis continuously produces rotifer eggs. After the enrichment is completed, collect the nutrient-rich rotifer eggs, disinfect them with 0.5 ppm sodium hypochlorite, wash them thoroughly, and place them in aerated clean seawater with a salinity of 10‰ and a temperature of 15 °C for standby. The collection of rotifer eggs is carried out as follows: Scoop up the enriched rotifers, drain the water, add 10% of the weight of the rotifers of deep-sea fish oil, and mix gently to lubricate and prevent damage to the rotifer eggs during the cleaning process; Place the rotifers in a 200-mesh sieve, and place a 500-mesh sieve under the 200-mesh sieve to collect the rotifer eggs. The 500-mesh sieve is always immersed in water to prevent the rotifer eggs from dehydrating. Use seawater with a pressure of 0.4 mpa to repeatedly rinse the rotifers until the rotifer eggs are detached and flow through the 200-mesh sieve into the 500-mesh sieve, thus achieving the collection of rotifer eggs;

[0062] S3. Prepare clean seawater with a salinity of 10‰ in an indoor pond of 25 m 3 at a water temperature of 32 °C. Place one aeration head per square meter, and add 1×10 6 cfu / m 3 Bacillus spores into the pond, and then put in the treated fertilized eggs; After the fry start to feed, add 20 ppm Chlorella vulgaris and 1×10 7 cfu / m 3 Lactic acid bacteria into the pond; 12 hours after the fry start to feed, feed rotifer eggs to facilitate the fry to start feeding. The final concentration of rotifer eggs in the water tank is 10 eggs / mL, and feed rotifer eggs every 8 hours to maintain the final concentration of 10 eggs / mL for 4 consecutive days. The light is a 3000 lux full-spectrum light, which is turned on continuously for 24 hours; From the 5th to the 8th day after the fry start to feed, feed ultra-microfolded Brachionus rotundiformis with a major axis less than 140 μm and a minor axis less than 90 μm. Start feeding nauplii of Artemia salina on the 9th day after the fry start to feed;

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

[0064] S4. Before putting the fry into the outdoor pond, it is necessary to disinfect the outdoor pond and maintain the water quality stability. The disinfection treatment is carried out according to the following method: Through an electrolytic seawater chlorine dioxide generator and 200 m 3A protein separator with a capacity of / h circulates and disinfects the seawater in the outdoor pond to keep the bacterial content at a low level. During the circulation process, the current is 80 A and the voltage is 6 V. The water in the pond is continuously pumped for disinfection. The chlorine production of the discharged seawater is 0.15 mg / L. The residence time of the water body in the protein separator is 2 minutes. At the discharge end, a waterwheel aerator is added to push the seawater in the pond and promote the mixing of the electrolyzed seawater and the original water body in the pond. The daily circulation volume is 60% of the total water volume. The number of Gram-negative bacteria is not higher than 6 cfu / mL, and the number of Gram-positive bacteria is not higher than 9 cfu / mL.

[0065] Gently place the fry into the outdoor pond and feed them with nauplii of Artemia until they are full. 21 days after hatching, feed them with copepods until they are full. 35 days after hatching, fully developed juvenile fish can be obtained.

[0066] Specifically, to illustrate the advantages of the proposed fry-rearing method in this embodiment, traditional fry-rearing methods are used in 3 ponds respectively. 0.2 kg of Epinephelus lanceolatus fertilized eggs are put into each pond. The traditional fry-rearing method is carried out as follows: Disinfect the seawater, put the fish eggs into it. After the fish open their mouths, add 1×10 7 cfu / m 3 of Chlorella and 0.05×10^8 rotifers per cubic meter. 3 After 12 days, feed them with nauplii of Cyclops. After 20 days, feed them with Cyclops. After 35 days of development, juvenile fish that have completed metamorphosis can be obtained.

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

[0068] Table 2 Fry-rearing 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 not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for large-scale breeding of saddle grouper, characterized in that: The steps include: S1. Dissolve the fertilized eggs to facilitate the breaking of the membrane; S2, using nutrient solution to enhance the ultrafine Brachionus plicatilis rotifer, collecting rotifer eggs and feeding them to the fry after hatching; 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 fry start to hatch, add 20ppm of Chlorella vulgaris and 1×10 7 cfu / m 3 Lactic acid bacteria; 12 hours after the fry hatch, feed rotifer eggs to facilitate the fry hatching. The final concentration of rotifer eggs in the pool 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 2000-3000lux full-spectrum light, which is turned on 24 hours; from the 5th to the 8th day after the fry hatch, feed ultra-microscopic 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 the fry hatch; On the 13th day after hatching, 0.5ppm vitamin C and 0.1ppm eugenol were injected, all light sources in the hatching space were turned off to maintain a completely dark environment, and a searchlight with a light intensity greater than 5000lux was used to induce the fry to gather, and the fry were collected and transported 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, characterized in that: In step S2, the reinforcement of the ultrafine Brachionus plicatilis 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, adding the ultrafine Brachionus plicatilis rotifer to the hatching bucket for reinforcement, using pure oxygen to provide oxygen, the dissolved oxygen is not less than 12mg / L, and the reinforcement is carried out for 12h. After the reinforcement is completed, the rotifer is fished out and put into another hatching bucket with nutrient mother solution for secondary reinforcement, and the reinforcement time is 12h.

3. The seedling raising method according to claim 2, characterized in that: The preparation method of the nutrient mother solution is as follows: 10g / L of Pseudochlorophyll 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 composite premix feed, 2g / L of emulsifier monoglyceride, add purified water, and mix in a homogenizer to form an emulsion.

4. The seedling raising method according to claim 1, characterized in that: In step S2, the rotifer eggs are collected as follows: the strengthened rotifers are picked up, the water is drained, and deep-sea fish oil of 10% of the weight of the rotifers is added; 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 into the 300-500-mesh sieve through the 200-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.

5. The seedling raising method according to claim 1, characterized in that: In step S1, the digestion treatment is carried out according to the following steps: inject clean seawater with a salinity of 25-33‰ into an incubation bucket with a volume of 500-1000L, aerate vigorously, and add 3ppm povidone iodine; inject clean seawater with a salinity of 25-33‰ into another incubation bucket with a volume of 500-1000L, aerate vigorously, add 0.5ppm trypsin, 1ppm glutathione, 1ppm ethylenediaminetetraacetic acid, 0.2ppm zinc chloride, and adjust the pH of the seawater to 7.8-8.5, and control the temperature to 28-32°C; Place the fertilized eggs in an incubation bucket with povidone iodine, take out the fertilized eggs after 15 minutes of aeration, and wash them with clean seawater. Then place them in an incubation bucket with trypsin, take out the fertilized eggs after 30 minutes of aeration, and wash them with clean seawater containing 0.5 ppm fetal bovine serum. Then place the treated fertilized eggs in an indoor water pool prepared in advance.

6. The seedling raising method according to claim 1, characterized in that: 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 current of the circulation process 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 the electrolyzed seawater and the original water in the pond. The daily circulating water volume is 60-80% of the total water. Gram-negative bacteria are not higher than 20 cfu / mL, and Gram-positive bacteria are not higher than 50cfu / mL.

Images