Indoor detoxification seedling raising method for plectropomus leopardus

Abstract

The invention discloses an indoor detoxification seedling raising method for plectropomus leopardus, and relates to the technical field of biology. The seedling raising method comprises the steps that after an indoor seedling raising pond is sterilized and killed, newly hatched seedlings of plectropomus leopardus are put into the indoor seedling raising pond, and after the newly hatched seedlings open to eat food, different sterilized and killed baits are adopted for feeding the seedlings in a stepped mode for seedling raising culture. According to the method, multiple baits such as nannochloropsis oculata, oyster larvae, SS rotifers, S rotifers, L rotifers, fairy shrimp nauplius larvae, copepod nauplius larvae, copepod middle worms, fairy shrimp adults and copepod adults are fed in a stepped mode, rapid growth of the plectropomus leopardus juvenile fish is promoted, the disease resistance of the juvenile fish is effectively improved, the environment adaptability is enhanced, and the survival rate of the plectropomus leopardus is increased. And the survival rate is well improved.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, in particular to an indoor virus-free seedling raising method for leopard gill bass. Background Art

[0002] Leopard gill perch (Plectropomus leopardus), also known as Eastern star grouper, is a warm-water fish and a high-end fish. It grows fast, has delicious meat and high nutritional value. It is an economic fish with a large consumption among groupers, and its breeding scale is expanding year by year. Leopard gill perch is not only popular for its high edible value, but also has a high ornamental value due to its gorgeous body color.

[0003] The breeding process of leopard gill perch is complex and requires high technology. The breeding process of leopard gill perch is complex and requires high water quality, bait size and type, pathogen prevention and control, etc. Especially in the process of pheasant fry cultivation, turbid water, unpalatable bait, and bait carrying many pathogens will often lead to reduced feeding frequency, insufficient feeding desire, and disease invasion of pheasant fry, which directly leads to large-scale death of fry, further reducing the overall survival rate of seedlings, and ultimately resulting in insufficient supply of leopard gill perch seedlings, seriously restricting the large-scale development of its breeding industry. In the existing seedling breeding technology, the selection of bait for leopard gill perch fry, feeding strategy, and pathogen prevention and control are one of the key factors affecting the success of seedling breeding.

[0004] At present, most of the reports and research on the bait of leopard gill perch are mainly based on single rotifers and artificial compound feeds (such as patents CN108142734A and CN114343084A), and most feeding strategies use Nannochloropsis and rotifers or Artemia (such as patent CN113907022A). Its disadvantages are that it fails to ensure the palatability of the bait at different stages of fry hatching, or lacks the pertinence of the changes in bait at different stages, and lacks strict prevention and control measures for entities such as water bodies, baits, and tools that can contact fry, resulting in slow growth of young fish and constant threats of diseases, which in turn affects the survival rate and quality of seedlings. Therefore, it is necessary to develop a new indoor detoxification seedling method for leopard gill perch to improve the survival rate and seedling quality of seedlings. Summary of the invention

[0005] The invention aims to provide an indoor virus-free seedling raising method for leopard gill perch to solve the problems existing in the above-mentioned prior art. The seedling raising method adopts multiple baits for step-feeding, which not only promotes the rapid growth of leopard gill perch fry, effectively improves the disease resistance of seedlings, but also enhances the environmental adaptability and better improves the survival rate.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The invention provides an indoor virus-free seedling raising method for leopard gill perch, comprising the steps of sterilizing an indoor seedling raising pool, putting newly hatched leopard gill perch into the pool, and feeding the sterilized bait to the newly hatched seedlings in a step-by-step manner after the newly hatched seedlings start to eat.

[0008] The step-by-step feeding seedling culture comprises the following steps:

[0009] One day before opening, feed Nannochloropsis pseudochloropsis;

[0010] Feed Nannochloropsis pseudochlorophylla, oyster larvae and SS rotifers on the 1st to 4th day after opening;

[0011] Feed Nannochloropsis pseudochlorophylla and SS rotifers on the 5th to 8th day after opening;

[0012] Feed Nannochloropsis pseudochlorophylla and S rotifer on the 9th to 12th day of opening;

[0013] Feed Nannochloropsis pseudochlorophylla and L rotifers on the 13th to 18th day after opening;

[0014] Feed Artemia nauplii, copepod nauplii and copepod midges on days 19-24 of opening;

[0015] Feed the fish with adult Artemia and adult copepods 25-40 days after opening.

[0016] Furthermore, it is characterized in that one day before opening, the feeding density of the Nannochloropsis is 32,000-50,000 / mL.

[0017] Furthermore, within 1-4 days after opening, the feeding density of the Nannochloropsis pseudochlorophylla is 24,000-40,000 / mL; the feeding density of the oyster larvae is 15-20 / mL; and the feeding density of the SS rotifer is 10-15 / mL.

[0018] Furthermore, at 5-18 days after opening, the feeding density of the Nannochloropsis pseudochlorophylla is 16,000-30,000 / mL, and the feeding density of the SS rotifer, the S rotifer and the L rotifer are all 10-15 / mL.

[0019] Furthermore, at 19-24 days after opening, the feeding density of the Artemia nauplii, the copepod nauplii and the copepod midges are all 1-1.5 / mL.

[0020] Furthermore, at 25-40 days after opening, the feeding density of the Artemia adults and the copepod adults is 1-1.5 / mL.

[0021] Furthermore, before feeding, the SS rotifer, the S rotifer and the L rotifer are all treated with a strengthening liquid.

[0022] Furthermore, each 300 mL of the fortified liquid contains 4 g of fish oil, 1 g of marine red yeast, 2 g of vitamin C, 1 g of speed regulating and speed supplement, 1 g of oligosaccharide and 10 g of Schizochytrium.

[0023] Furthermore, during the step-feeding seedling culture process, the water temperature of the seedling pond is controlled at 26-29°C, the dissolved oxygen is 5-10 mg / L, the pH is 8.1-8.5, the ammonia nitrogen is lower than 0.02 mg / L, and the nitrite is lower than 0.05 mg / L.

[0024] Furthermore, during the step-feeding seedling culture process, the light intensity is controlled at 4000-8000lx.

[0025] The present invention discloses the following technical effects:

[0026] The invention provides a method for preparing a leopard gill perch with high efficiency indoor seedling raising and virus-free seedling raising, which can meet the nutritional needs of young fish at different growth stages by optimizing the feeding strategy of bait and adopting multiple baits for step feeding. For the leopard gill perch variety, the method of the invention is adopted to raise seedlings for about 40 days, the incidence of seedling raising is low, the survival rate is high, the yield of fry is large, the seedling specification is ≥3cm, the seedling quality is high, the requirement of rapid seedling raising can be met, and the problem of insufficient leopard gill perch seedlings is solved, which is conducive to the expansion of the scale of leopard gill perch breeding industry and promotes the development of leopard gill perch breeding industry.

[0027] The invention adopts multiple baits such as Nannochloropsis pseudochlorophylla, oyster larvae, SS rotifers, S rotifers, L rotifers, Artemia nauplii, copepod nauplii, copepod mesopidae, Artemia adults, copepod adults, etc. for step-feeding, which not only promotes the rapid growth of leopard gill perch fry and effectively improves the disease resistance of seedlings, but also enhances the ability to adapt to the environment and better improves the survival rate. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0031] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0032] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0033] The speed regulator in the present invention was purchased from Shandong Baolai Lilai Bioengineering Co., Ltd., product standard number: Q / 370902SBL658.

[0034] The oligosaccharide in the present invention is purchased from Shandong Baolai Lilai Biotechnology Co., Ltd., product standard number: Q / 370902SBL465.

[0035] The length of the Artemia nauplii used in the following examples is in the range of 0.35-0.5 mm; the length of the copepod (Mongoloid flea) nauplii is in the range of 0.3-0.5 mm; the length of the copepod (Mongoloid flea) is in the range of 0.5-0.8 mm; the length of the Artemia adult and the copepod (Mongoloid flea) adult is in the range of 0.8-1.5 mm.

[0036] Example 1

[0037] 1. Preparation before egg placement:

[0038] 1. The indoor nursery pool is a 25m3 round blue PVC pool with a water depth of 1.2m. It contains oxygen pipes and heating pipes. The drainage system of the nursery pool is designed with bottom drainage and surface drainage. The pool bottom is designed to be low in the middle and high around. The water inlet is covered with a filter cotton bag. The drainage pipe is set in the middle and the drainage pipe is covered with an 80-mesh net. Each nursery pool is equipped with 16 air stones evenly distributed.

[0039] 2. The water for nursery is the seawater from the open sea that has been filtered by sand filter tanks (to filter out large particles), filtered by ultrafiltration equipment (to filter out small particles), and sterilized by ultraviolet rays before entering the pool. It is then disinfected by bleach and detoxified by baking soda to remove parasites, bacteria, viruses and other microorganisms in the water.

[0040] 2. Fertilized egg selection and egg placement:

[0041] 1. Before releasing the eggs, place them in the nursery pond to warm for 20 minutes, then pour the eggs and water into a sterilized clean bucket and rotate them slightly for a few circles. After they are still, separate the live eggs from the dead eggs. Select the high-quality eggs that are healthy, full, undamaged, and free of debris in the upper layer of the water and pour them into a 100-mesh scoop net (soft net). Add clean seawater to the remaining water and eggs and repeat the separation operation twice. Rinse the collected high-quality eggs with clean seawater 3 times.

[0042] 2. Weigh 100g of eggs and put them into a 400L hatching bucket. The water quality of the hatching bucket is the same as that of the nursery pond. Avoid strong light during the incubation period. Adjust the oxygen to a higher level to break up the eggs and then stabilize them. The eggs will emerge 24-27 hours after fertilization. After the fry are hatched, remove the surface egg liquid, drain the dead eggs at the bottom, and move the fry to the nursery pond.

[0043] 3. Feeding the fry

[0044] 1. One day before opening: Feed Nannochloropsis

[0045] The night before the fry start to hatch, add concentrated Nannochloropsis pseudochlororaphis to the nursery pond at a density of 32,000 / mL, and control the water visibility at around 50 cm.

[0046] The Nannochloropsis algae fed was bottled concentrated algae, stored at 0-4°C. Before feeding, it was thawed at room temperature, then diluted with fresh seawater, aerated for 0.5h, and the residue was filtered using a 500 mesh.

[0047] 2. 1-4 days after opening: Feed Nannochloropsis pseudochlorophyll + oyster larvae + SS rotifers

[0048] The feeding density of Nannochloropsis spp. was 24,000 / mL; the feeding density of oyster larvae was 20 / mL; and the feeding density of enhanced SS rotifers was 15 / mL.

[0049] The night before feeding, select oysters with full gonads and good development, collect oyster sperm and eggs for artificial insemination, put the fertilized eggs in a 500-mesh net bag, wash them three times with clean seawater, and then incubate them in a hatching bucket for 8 hours. Use a 500-mesh net to collect oyster larvae, wash them twice with seawater after collection, and then feed them.

[0050] Rotifer temporary culture and strengthening: One day before feeding, the rotifers were temporarily cultured in a 400L clean seawater hatching bucket (containing strengthening solution), disinfected with 100mL bleach before feeding, detoxified after 4-8 hours, and no algae were added during the temporary culture. The strengthening solution (per 300 million rotifers) includes: 4g fish oil, 1g marine red yeast, 2g vitamin C, 1g speed regulating speed supplement, 1g oligosaccharide, 10g Schizochytrium algae, dissolved in 300mL seawater, and homogenized for 6 minutes using a homogenizer at 20000r / min.

[0051] 3. 5-8 days after opening: feed Nannochloropsis algae + SS rotifers; 9-12 days after opening: feed Nannochloropsis algae + S rotifers; 13-18 days after opening: feed Nannochloropsis algae + L rotifers.

[0052] The feeding density of Nannochloropsis spp. was 16,000 / mL.

[0053] Feed the enriched SS rotifers, S rotifers or L rotifers (temporary culture and enrichment methods are the same as above), the density of rotifers is 15 / mL, and replenish the enriched SS rotifers, S rotifers or L rotifers from time to time by observing the number of rotifers in the water and the number of fish.

[0054] The rotifers were cleaned with a small amount of water using 200 mesh (L rotifers), 250 mesh (S rotifers) and 300 mesh (SS rotifers) to remove other unicellular algae such as Nannochloropsis in the rotifer water.

[0055] 4. 19-24 days after hatching: Feed newly hatched Artemia nauplii + copepod nauplii + copepod larvae

[0056] Newly hatched Artemia nauplii, copepod nauplii, and copepod mesona were temporarily cultured in fresh seawater, disinfected with hydrogen peroxide for 10 min, and fed after cleaning at a feeding density of 1 / mL.

[0057] Copepod nauplii: collect them with 300 mesh, filter out soil and adults with 200 mesh, then put them into fresh seawater for 8 hours, and add chlorine dioxide effervescent tablets for disinfection; Artemia nauplii: put Artemia eggs into 30℃ seawater for incubation, shade the top of the incubation bucket for 15 minutes after 20-24 hours, then collect them with 200 mesh at the bottom of the incubation bucket, then put the worms back into 80 mesh scoop net to remove the shells, collect them with 200 mesh, and feed them.

[0058] 5. 25-40 days after opening: Feed adult Artemia + adult copepods

[0059] The feeding density of Artemia adults and copepod adults was 1 / mL.

[0060] Adult copepods: collect the worms with a 200-mesh net, add an 80-mesh filter on top to filter out the dirt and debris in the worms, then put them into fresh seawater for temporary culture for 8 hours, and add chlorine dioxide effervescent tablets for disinfection; Adult Artemia: Put the purchased adult Artemia into fresh seawater for temporary culture, disinfect with hydrogen peroxide for 10 minutes, and then wash it before feeding.

[0061] 4. Daily management of the nursery pond is as follows:

[0062] 1. Daily observation of fry behavior: Observe the fry in the nursery pond every day to see if they have normal and abnormal behavior characteristics. Normal behavior includes group foraging and phototropism. In addition, in the later stage, the fry will move closely to the wall of the nursery pond and swim around the pond. Abnormal behavior includes slow movement, imbalance and sideways rollover, decreased appetite and rapid breathing.

[0063] 2. Water quality index monitoring: Regularly monitor the water quality indexes of the nursery pond, including water temperature, dissolved oxygen, pH, ammonia nitrogen, nitrite, etc. Ensure that the water temperature of the nursery pond is within the range of 26-29℃, dissolved oxygen is 5-10mg / L, pH is 8.1-8.5, ammonia nitrogen is less than 0.02mg / L, and nitrite is less than 0.05mg / L.

[0064] 3. Vibrio detection: Vibrio plates are plated in the nursery ponds every day, and the types and contents of Vibrio in each nursery pond are counted.

[0065] 4. Animal health product feeding: Each 25m3 nursery pond is fed with 100mL / d EM bacteria, 100mL / d lactic acid bacteria, 20g / d Bacillus and 4mL Vibrio net.

[0066] 5. Water change and bottom suction: Start changing water on the 6th day after opening. Change 10% of the water on the first day, 20% on the second day, and so on. Gradually increase the amount of water change. Add anti-stress drugs half an hour before changing the water, and suction the bottom of the nursery pond to drain sewage in time.

[0067] 6. Lighting: The workshop uses LED fill lights for lighting. The light intensity is controlled at 4000-80001x in the middle of the pool, about 1-1.5 meters from the water surface. The lighting time is controlled at about 12 hours. The workshop is well ventilated.

[0068] Example 2

[0069] 1. Preparation before egg placement:

[0070] 1. The indoor nursery pool is a 25m3 round blue PVC pool with a water depth of 1.2m. It contains oxygen pipes and heating pipes. The drainage system of the nursery pool is designed with bottom drainage and surface drainage. The pool bottom is designed to be low in the middle and high around. The water inlet is covered with a filter cotton bag. The drainage pipe is set in the middle. The drainage pipe is covered with an 80-mesh net. Each nursery pool is equipped with 16 air stones evenly distributed.

[0071] 2. The water for nursery is the seawater from the open sea that has been filtered by sand filter tanks (to filter out large particles), filtered by ultrafiltration equipment (to filter out small particles), and sterilized by ultraviolet rays before entering the pool. It is then disinfected by bleach and detoxified by baking soda to remove parasites, bacteria, viruses and other microorganisms in the water.

[0072] 2. Fertilized egg selection and egg placement:

[0073] 1. Before releasing the eggs, place them in the nursery pond for 25 minutes to warm up. Then pour the eggs and water into a sterilized clean bucket and rotate them slightly for a few circles. After they are still, separate the live eggs from the dead eggs. Select the high-quality eggs that are healthy, full, undamaged, and free of debris in the upper layer of the water and pour them into a 100-mesh scoop net (soft net). Add clean seawater to the remaining water and eggs and repeat the separation operation 3 times. Rinse the collected high-quality eggs with clean seawater 3 times.

[0074] 2. Weigh 100g of eggs and put them into a 400L hatching bucket. The water quality of the hatching bucket is the same as that of the nursery pond. Avoid strong light during the incubation period. Adjust the oxygen to a higher level to break up the eggs and then stabilize them. The eggs will emerge 24-27 hours after fertilization. After the fry are hatched, remove the surface egg liquid, drain the dead eggs at the bottom, and move the fry to the nursery pond.

[0075] 3. Feeding the fry

[0076] 1. One day before opening: Feed Nannochloropsis

[0077] The night before the fry start to hatch, add concentrated Nannochloropsis pseudochlororaphis to the nursery pond at a density of 40,000 fry / mL, and control the water visibility at around 50 cm.

[0078] The Nannochloropsis algae fed was bottled concentrated algae, stored at 0-4°C. Before feeding, it was thawed at room temperature, then diluted with fresh seawater, aerated for 0.5h, and the residue was filtered using a 500 mesh.

[0079] 2. 1-4 days after opening: Feed Nannochloropsis pseudochlorophyll + oyster larvae + SS rotifers

[0080] The feeding density of Nannochloropsis spp. was 30,000 / mL; the feeding density of oyster larvae was 15 / mL; and the feeding density of enhanced SS rotifers was 10 / mL.

[0081] The night before feeding, select oysters with full gonads and good development, collect oyster sperm and eggs for artificial insemination, put the fertilized eggs in a 500-mesh net bag, wash them three times with clean seawater, and then incubate them in a hatching bucket for 8 hours. Use a 500-mesh net to collect oyster larvae, wash them twice with seawater after collection, and then feed them.

[0082] Rotifer temporary culture and strengthening: One day before feeding, the rotifers were temporarily cultured in a 400L clean seawater hatching bucket (containing strengthening solution), disinfected with 100mL bleach before feeding, detoxified after 4-8 hours, and no algae were added during the temporary culture. The strengthening solution (per 300 million rotifers) includes: 4g fish oil, 1g marine red yeast, 2g vitamin C, 1g speed regulating speed supplement, 1g oligosaccharide, 10g Schizochytrium algae, dissolved in 300mL seawater, and homogenized for 6 minutes using a homogenizer at 20000r / min.

[0083] 3. 5-8 days after opening: feed Nannochloropsis algae + SS rotifers; 9-12 days after opening: feed Nannochloropsis algae + S rotifers; 13-18 days after opening: feed Nannochloropsis algae + L rotifers.

[0084] The feeding density of Nannochloropsis spp. was 20,000 / mL.

[0085] Feed the enriched SS rotifers, S rotifers or L rotifers (temporary culture and enrichment methods are the same as above), the density of rotifers is 10 / mL, and replenish the enriched SS rotifers, S rotifers or L rotifers from time to time by observing the number of rotifers in the water and the number of fish.

[0086] The rotifers were cleaned with a small amount of water using 200 mesh (L rotifers), 250 mesh (S rotifers) and 300 mesh (SS rotifers) to remove other unicellular algae such as Nannochloropsis in the rotifer water.

[0087] 4. 19-24 days after hatching: Feed newly hatched Artemia nauplii + copepod nauplii + copepod larvae

[0088] Newly hatched Artemia nauplii, copepod nauplii, and copepod mesona were temporarily cultured in fresh seawater, disinfected with hydrogen peroxide for 10 min, and fed after cleaning at a feeding density of 1.5 per mL.

[0089] Copepod nauplii: collect them with 300 mesh, filter out soil and adults with 200 mesh, then put them into fresh seawater for 8 hours, and add chlorine dioxide effervescent tablets for disinfection; Artemia nauplii: put Artemia eggs into 30℃ seawater for incubation, shade the top of the incubation bucket for 15 minutes after 20-24 hours, then collect them with 200 mesh at the bottom of the incubation bucket, then put the worms back into 80 mesh scoop net to remove the shells, collect them with 200 mesh, and feed them.

[0090] 5. 25-40 days after opening: Artemia adult + copepod adult

[0091] The feeding density of Artemia adults and copepod adults was 1.5 / mL.

[0092] Adult copepods: collect the worms with a 200-mesh net, add an 80-mesh filter on top to filter out the dirt and debris in the worms, then put them into fresh seawater for temporary culture for 8 hours, and add chlorine dioxide effervescent tablets for disinfection; Adult Artemia: Put the purchased adult Artemia into fresh seawater for temporary culture, disinfect with hydrogen peroxide for 10 minutes, and then wash it before feeding.

[0093] 4. Daily management of the nursery pond is as follows:

[0094] 1. Daily observation of fry behavior: Observe the fry in the nursery pond every day to see if they have normal and abnormal behavior characteristics. Normal behavior includes group foraging and phototropism. In addition, in the later stage, the fry will move closely to the wall of the nursery pond and swim around the pond. Abnormal behavior includes slow movement, imbalance and sideways rollover, decreased appetite and rapid breathing.

[0095] 2. Water quality index monitoring: Regularly monitor the water quality indexes of the nursery pond, including water temperature, dissolved oxygen, pH, ammonia nitrogen, nitrite, etc. Ensure that the water temperature of the nursery pond is within the range of 26-29℃, dissolved oxygen is 5-10mg / L, pH is 8.1-8.5, ammonia nitrogen is less than 0.02mg / L, and nitrite is less than 0.05mg / L.

[0096] 3. Vibrio detection: Vibrio plates are plated in the nursery ponds every day, and the types and contents of Vibrio in each nursery pond are counted.

[0097] 4. Animal health product feeding: Each 25m3 nursery pond is fed with 100mL / d EM bacteria, 100mL / d lactic acid bacteria, 20g / d Bacillus and 4mL Vibrio net.

[0098] 5. Water change and bottom suction: Start changing water on the 6th day after opening. Change 10% of the water on the first day, 20% on the second day, and so on. Gradually increase the amount of water change. Add anti-stress drugs half an hour before changing the water, and suction the bottom of the nursery pond to drain sewage in time.

[0099] 6. Lighting: The workshop uses LED fill lights for lighting. The light intensity is controlled at 4000-80001x in the middle of the pool, about 1-1.5 meters from the water surface. The lighting time is controlled at about 12 hours. The workshop is well ventilated.

[0100] Example 3

[0101] 1. Preparation before egg placement:

[0102] 1. The indoor nursery pool is a 25m3 round blue PVC pool with a water depth of 1.2m. It contains oxygen pipes and heating pipes. The drainage system of the nursery pool is designed with bottom drainage and surface drainage. The pool bottom is designed to be low in the middle and high around. The water inlet is covered with a filter cotton bag. The drainage pipe is set in the middle and the drainage pipe is covered with an 80-mesh net. Each nursery pool is equipped with 16 air stones evenly distributed.

[0103] 2. The water for nursery is the seawater from the open sea that has been filtered by sand filter tanks (to filter out large particles), filtered by ultrafiltration equipment (to filter out small particles), and sterilized by ultraviolet rays before entering the pool. It is then disinfected by bleach and detoxified by baking soda to remove parasites, bacteria, viruses and other microorganisms in the water.

[0104] 2. Fertilized egg selection and egg placement:

[0105] 1. Before releasing the eggs, place them in the nursery pond for 25 minutes to warm up. Then pour the eggs and water into a sterilized clean bucket and rotate them slightly for a few circles. After they are still, separate the live eggs from the dead eggs. Select the high-quality eggs that are healthy, full, undamaged, and free of debris in the upper layer of the water and pour them into a 100-mesh scoop net (soft net). Add clean seawater to the remaining water and eggs and repeat the separation operation 3 times. Rinse the collected high-quality eggs with clean seawater 3 times.

[0106] 2. Weigh 100g of eggs and put them into a 400L hatching bucket. The water quality of the hatching bucket is the same as that of the nursery pond. Avoid strong light during the incubation period. Adjust the oxygen to a higher level to break up the eggs and then stabilize them. The eggs will emerge 24-27 hours after fertilization. After the fry are hatched, remove the surface egg liquid, drain the dead eggs at the bottom, and move the fry to the nursery pond.

[0107] 3. Feeding the fry

[0108] 1. One day before opening: Feed Nannochloropsis

[0109] The night before the fry start to hatch, add concentrated Nannochloropsis pseudochlorophylla to the nursery pond at a density of 50,000 / mL, and control the water visibility at around 50 cm.

[0110] The Nannochloropsis algae fed was bottled concentrated algae, stored at 0-4°C. Before feeding, it was thawed at room temperature, then diluted with fresh seawater, aerated for 0.5h, and the residue was filtered using a 500 mesh.

[0111] 2. 1-4 days after opening: Feed Nannochloropsis pseudochlorophyll + oyster larvae + SS rotifers

[0112] The feeding density of Nannochloropsis spp. was 40,000 / mL; the feeding density of oyster larvae was 12 / mL; and the feeding density of enhanced SS rotifers was 12 / mL.

[0113] The night before feeding, select oysters with full gonads and good development, collect oyster sperm and eggs for artificial insemination, put the fertilized eggs in a 500-mesh net bag, wash them three times with clean seawater, and then incubate them in a hatching bucket for 8 hours. Use a 500-mesh net to collect oyster larvae, wash them twice with seawater after collection, and then feed them.

[0114] Rotifer temporary culture and strengthening: One day before feeding, the rotifers were temporarily cultured in a 400L clean seawater hatching bucket (containing strengthening solution), disinfected with 100mL bleach before feeding, detoxified after 4-8 hours, and no algae were added during the temporary culture. The strengthening solution (per 300 million rotifers) includes: 4g fish oil, 1g marine red yeast, 2g vitamin C, 1g speed regulating speed supplement, 1g oligosaccharide, 10g Schizochytrium algae, dissolved in 300mL seawater, and homogenized for 6 minutes using a homogenizer at 20000r / min.

[0115] 3. 5-8 days after opening: feed Nannochloropsis algae + SS rotifers; 9-12 days after opening: feed Nannochloropsis algae + S rotifers; 13-18 days after opening: feed Nannochloropsis algae + L rotifers.

[0116] The feeding density of Nannochloropsis spp. was 30,000 / mL.

[0117] The enriched SS rotifers, S rotifers or L rotifers were fed (the temporary culture and enrichment methods were the same as above), the density of rotifers was 12 / mL, and the enriched SS rotifers, S rotifers or L rotifers were supplemented from time to time by observing the number of rotifers in the water and the number of fish.

[0118] The rotifers were cleaned with a small amount of water using 200 mesh (L rotifers), 250 mesh (S rotifers) and 300 mesh (SS rotifers) to remove other unicellular algae such as Nannochloropsis in the rotifer water.

[0119] 4. 19-24 days after hatching: Feed newly hatched Artemia nauplii + copepod nauplii + copepod larvae

[0120] Newly hatched Artemia nauplii, copepod nauplii, and copepod mesona were temporarily cultured in fresh seawater, disinfected with hydrogen peroxide for 10 min, and fed after cleaning at a feeding density of 1.2 pieces / mL.

[0121] Copepod nauplii: collect them with 300 mesh, filter out soil and adults with 200 mesh, then put them into fresh seawater for 8 hours, and add chlorine dioxide effervescent tablets for disinfection; Artemia nauplii: put Artemia eggs into 30℃ seawater for incubation, shade the top of the incubation bucket for 15 minutes after 20-24 hours, then collect them with 200 mesh at the bottom of the incubation bucket, then put the worms back into 80 mesh scoop net to remove the shells, collect them with 200 mesh, and feed them.

[0122] 5. 25-40 days after opening: Artemia adult + copepod adult

[0123] The feeding density of Artemia adults and copepod adults was 1.2 / mL.

[0124] Adult copepods: collect the worms with a 200-mesh net, add an 80-mesh filter on top to filter out the dirt and debris in the worms, then put them into fresh seawater for temporary culture for 8 hours, and add chlorine dioxide effervescent tablets for disinfection; Adult Artemia: Put the purchased adult Artemia into fresh seawater for temporary culture, disinfect with hydrogen peroxide for 10 minutes, and then wash it before feeding.

[0125] 4. Daily management of the nursery pond is as follows:

[0126] 1. Daily observation of fry behavior: Observe the fry in the nursery pond every day to see if they have normal and abnormal behavior characteristics. Normal behavior includes group foraging and phototropism. In addition, in the later stage, the fry will move closely to the wall of the nursery pond and swim around the pond. Abnormal behavior includes slow movement, imbalance and sideways rollover, decreased appetite and rapid breathing.

[0127] 2. Water quality index monitoring: Regularly monitor the water quality indexes of the nursery pond, including water temperature, dissolved oxygen, pH, ammonia nitrogen, nitrite, etc. Ensure that the water temperature of the nursery pond is within the range of 26-29℃, dissolved oxygen is 5-10mg / L, pH is 8.1-8.5, ammonia nitrogen is less than 0.02mg / L, and nitrite is less than 0.05mg / L.

[0128] 3. Vibrio detection: Vibrio plates are plated in the nursery ponds every day, and the types and contents of Vibrio in each nursery pond are counted.

[0129] 4. Animal health product feeding: Each 25m3 nursery pond is fed with 100mL / d EM bacteria, 100mL / d lactic acid bacteria, 20g / d Bacillus and 4mL Vibrio net.

[0130] 5. Water change and bottom suction: Start changing water on the 6th day after opening. Change 10% of the water on the first day, 20% on the second day, and so on. Gradually increase the amount of water change. Add anti-stress drugs half an hour before changing the water, and suction the bottom of the nursery pond to drain sewage in time.

[0131] 6. Lighting: The workshop uses LED fill lights for lighting. The light intensity is controlled at 4000-80001x in the middle of the pool, about 1-1.5 meters from the water surface. The lighting time is controlled at about 12 hours. The workshop is well ventilated.

[0132] Comparative Example 1

[0133] The same as Example 1, except that Nannochloropsis was not fed during the first 1-18 days of incubation.

[0134] Comparative Example 2

[0135] The same as Example 1, except that the oyster larvae were not fed for 1-4 days after opening.

[0136] Comparative Example 3

[0137] The same as Example 1, except that, from 5 to 40 days after opening, step feeding was not adopted, and Nannochloropsis spp. + SS rotifers were continuously fed, wherein the feeding density of Nannochloropsis spp. was 32,000 / mL, and the feeding density of SS rotifers was 15 / mL.

[0138] Test Example 1

[0139] In June 2024, seedlings were raised according to the methods of Examples 1-3 and Comparative Examples 1-3, respectively, and recorded as Study Groups 1-6. After the seedlings were raised, the survival rate, morbidity rate and average size of the fry of each group of leopard gill perch were counted, and the results are shown in Table 1.

[0140] Table 1 Seedling cultivation of leopard gill perch

[0141]

[0142] The results showed that the seedling specifications of the research groups 1-3 all met the seedling emergence standards (required body length ≥ 30cm), the seedling morbidity was low, and the survival rate was high. However, the seedling morbidity of the research groups 4-6 (comparative examples 1-3) was high, the survival rate was low, the fry production was greatly reduced, and the fry specifications failed to meet the requirements and failed to meet the requirements of rapid seedling.

[0143] Application Example 1

[0144] The leopard gill perch fry obtained by Examples 1-3 and Comparative Examples 1-3 were used to carry out a breeding experiment at the Hainan Oriental grouper breeding base. Each test group was fed with 10,000 leopard gill perch fry, and daily management was carried out according to the technical specifications for factory breeding of leopard gill perch during the breeding period. After one and a half years of breeding, adult fish were harvested, and the survival rate, morbidity rate, and average body weight were statistically analyzed. The results are shown in Table 2.

[0145] Table 2 The breeding situation of leopard gill perch

[0146]

[0147] The results showed that compared with comparative examples 1-3, examples 1-3 showed higher survival rate, lower morbidity and heavier adult fish weight in the culture process of leopard gill perch. This shows that using the fry obtained in examples 1-3 for culture can not only improve the quality of adult fish, but also significantly increase the yield.

[0148] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for indoor virus-free seedling raising of leopard gill perch, characterized in that: The method comprises the steps of sterilizing an indoor nursery pond, putting newly hatched seedlings of leopard gill perch into the pond, and feeding the newly hatched seedlings with different baits after sterilization and sterilization for seedling cultivation in a step-by-step manner after the newly hatched seedlings start to eat; The step-by-step feeding seedling culture comprises the following steps: One day before opening, feed Nannochloropsis pseudochloropsis; Feed Nannochloropsis pseudochlorophylla, oyster larvae and SS rotifers on the 1st to 4th day after opening; Feed Nannochloropsis pseudochlorophylla and SS rotifers on the 5th to 8th day after opening; Feed Nannochloropsis pseudochlorophylla and S rotifer on the 9th to 12th day of opening; Feed Nannochloropsis pseudochlorophylla and L rotifers on the 13th to 18th day after opening; Feed Artemia nauplii, copepod nauplii and copepod midges on days 19-24 of opening; Feed the fish with adult Artemia and adult copepods 25-40 days after opening.

2. The seedling raising method according to claim 1, characterized in that: One day before opening, the feeding density of the Nannochloropsis spp. is 32,000-50,000 / mL.

3. The seedling raising method according to claim 1, characterized in that: On the 1st to 4th day after opening, the feeding density of the Nannochloropsis pseudochlorophylla is 24,000 to 40,000 / mL; the feeding density of the oyster larvae is 15 to 20 / mL; and the feeding density of the SS rotifer is 10 to 15 / mL.

4. The seedling raising method according to claim 1, characterized in that: On the 5th to 18th day after the start of the culture, the feeding density of the Nannochloropsis pseudochlorophylla is 16,000 to 30,000 pieces / mL, and the feeding density of the SS rotifer, the S rotifer and the L rotifer are all 10 to 15 pieces / mL.

5. The seedling raising method according to claim 1, characterized in that: On days 19 to 24 after the start of the fish, the feeding density of the Artemia nauplii, the copepod nauplii and the copepod midges are all 1 to 1.5 / mL.

6. The method for raising seedlings according to claim 1, characterized in that: At 25-40 days after opening, the feeding density of the Artemia adults and the copepod adults is 1-1.5 / mL.

7. The seedling raising method according to claim 1, characterized in that: Before feeding, the SS rotifer, the S rotifer and the L rotifer are all treated with a strengthening solution.

8. The seedling raising method according to claim 7, characterized in that: Each 300mL of the fortified liquid contains 4g of fish oil, 1g of marine red yeast, 2g of vitamin C, 1g of speed-regulating and speed-replenishing supplement, 1g of oligosaccharides and 10g of Schizochytrium.

9. The seedling raising method according to claim 1, characterized in that: During the step-feeding seedling culture process, the water temperature of the seedling pond is controlled at 26-29° C., the dissolved oxygen is controlled at 5-10 mg / L, the pH is controlled at 8.1-8.5, the ammonia nitrogen is lower than 0.02 mg / L, and the nitrite is lower than 0.05 mg / L.

10. The seedling raising method according to claim 1, characterized in that: During the step-feeding seedling culture process, the light intensity is controlled at 4000-8000lx.

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