A method for raising shrimp seedlings effectively to improve their disease resistance

Abstract

The invention provides a seedling raising method for effectively improving the disease resistance of shrimp fry, comprising the following steps: S1 establishment of a seedling raising pond, S2 regulation of water quality, S3 seedling release, S4 cultivation and then desalination seedling emergence, etc. The invention significantly improves the activity of lysozyme in the serum of shrimp and improves the phenoloxidase through water quality regulation, adding bacterial phase and scientifically preparing bait, can perform immune recognition and epidemic prevention on the activation of zymogen when foreign pathogens invade and environmental stress, enhance the disease resistance of the body, effectively stimulate immune cells, thereby improving the disease resistance of shrimp, and achieving the effect of preventing red body disease and gill rot disease.

Description

Technical Field

[0001] The invention relates to the technical field of aquatic products, and in particular to a method for raising shrimp fry that effectively improves the disease resistance of shrimp fry. Background Art

[0002] The whiteleg shrimp (scientific name: Litopenaeus Vannamei) is an animal of the Penaeidae family and the genus Penaeus. The adult is up to 23 cm long, with a thin shell, a normal body color of blue-green or light blue-gray, and no markings on the body. The walking legs are often chalky, so it is called white-limbed shrimp; the natural habitat of the whiteleg shrimp is the muddy seabed, with a water depth of 0 to 72 meters. Adult shrimps mostly live in coastal waters close to the shore, while young shrimps like to forage and grow in estuaries with abundant bait. The whiteleg shrimp is an omnivorous species. Under artificial breeding conditions, it can eat organic debris in the pond and has a high requirement for the solidification rate of the feed. The whiteleg shrimp does not have a very strict demand for animal bait, as long as the protein ratio in the bait ingredients accounts for more than 20%, it can grow normally.

[0003] Red body disease, also known as Taura syndrome, is caused by Taura virus. The onset of the disease generally occurs 10-40 days after the shrimp fry are released. The main symptoms are red body color, especially the tip of the tail fan, soft shell, and empty stomach. Sick shrimp usually swim in groups at the edge of the pond. In severe cases, they roam on the water surface, are unresponsive, and do not eat. It usually lasts for 10-15 days, during which a large number of shrimp die. After that, the symptoms are alleviated and enter the chronic stage, but a few sick shrimp still die one after another. The cuticle of the carapace of some sick shrimp will show systemic black spots. There is currently no effective treatment for Taura virus. However, taking some active emergency measures in the early stage of the outbreak can effectively reduce its harm. Gill rot disease is caused by infection with Vibrio or other bacteria (such as Aeromonas). Symptoms are gray or black, swollen, brittle gill filaments, necrosis and ulceration from the tip to the base. Prevention and control measures: raise the water level, stabilize the water quality, maintain the water color, protect the bottom, remove toxic substances such as ammonia nitrogen and hydrogen sulfide; do not damage the shrimp body; use chlorine dioxide or bleaching powder to disinfect the entire pond. At present, the cultured white shrimp will have red body disease and gill rot disease, which will affect the efficiency of shrimp seedling cultivation and increase the cost of farmers. Summary of the invention

[0004] In view of this, the present invention proposes a method for raising shrimp fry that can effectively improve the disease resistance of shrimp fry to solve the above problems.

[0005] The technical solution of the present invention is achieved as follows: A method for raising shrimp seedlings to effectively improve the disease resistance of shrimp seedlings comprises the following steps:

[0006] S1. Establishment of nursery pond: After the water in nursery pond is treated by sand filtration, activated carbon and mesh filtration, the water bacteria phase is added to regulate the water.

[0007] S2. Water quality control: control the light intensity to 2000-45000Lx, temperature to 26-28℃, pH value to 6.0-8.5;

[0008] S3. Stocking: Select disease-free, healthy shrimp fry with a body length of 1.1 to 2.5 cm, and stock at a density of 80,000 to 120,000 shrimp / m 2 Put the shrimp fry into the nursery pond and feed them 10-50% of the shrimp fry weight 3-5 times a day;

[0009] S4. Cultivation: When the above shrimp fry develop into larvae, remove them and transfer them to the cultivation pond. Adjust the light intensity to 1200lx-2800lx, control the water temperature to 27-33℃, salinity to 26‰-33‰, pH to 8-8.3, and aerate at 36-45L / m per hour. 3 The aeration volume is increased, the aquaculture wastewater is replaced every day, and the water change volume increases from 10% to 50% of the initial daily water change volume. Artificial feed is added every day according to 35% to 60% of the weight of shrimp fry, 2 to 4 times a day, to dilute the fry.

[0010] Furthermore, the bacterial phase of the pond water of S1 is lactic acid bacteria, Rhodopseudomonas palustris and Nitrosobacter in a mass ratio of 1-3:0.2-0.8:0.5-1.2.

[0011] Furthermore, the concentration of the lactic acid bacteria is (150-180)×10 4 cfu / mL, the concentration of Rhodopseudomonas palustris is (100~200)×10 4 cfu / mL, the concentration of Nitrosobacter eutropha is (250~380)×10 4 cfu / mL.

[0012] Furthermore, the amount of bacteria in S1 is 2-5 L / m 3 .

[0013] Furthermore, the starter bait in S3 is 2-3 parts of S-type rotifers, 0.5-1 parts of medium-sized rotifers and 0.2-0.5 parts of copepod nauplii.

[0014] Furthermore, the artificial bait in S4 comprises the following raw materials in parts by weight: 2 to 5 parts of cod liver oil, 0.1 to 0.9 parts of vitamin C, 0.2 to 0.5 parts of microbial polysaccharides, 0.3 to 0.8 parts of ginsenosides, and 1.3 to 2.5 parts of biological enzymes.

[0015] Furthermore, the microbial polysaccharide is composed of pullulan α-glucan, Monascus polysaccharide and flavobacterium gum in a mass ratio of 3 to 5:1 to 2:5.

[0016] Furthermore, the biological enzyme is one or a combination of xylanase, lipase, cellulase, mannanase, protein complex enzyme, amylase, and xanthan gum lyase.

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

[0018] The shrimp seedling raising method of the present invention can improve the enzyme activity related to the disease resistance of the shrimp. The present invention significantly improves the lysozyme activity in the serum of the shrimp by adjusting the water quality, adding the bacterial phase and scientifically preparing the bait, improves the phenoloxidase, can activate the zymogen during the invasion of foreign pathogens and environmental stress, perform immune recognition and prevent diseases, enhance the disease resistance of the body, effectively stimulate immune cells, thereby improving the disease resistance of the shrimp, and achieving the effect of preventing red body disease and gill rot. DETAILED DESCRIPTION

[0019] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0020] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0021] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0022] Example 1

[0023] A method for raising shrimp seedlings to effectively improve their disease resistance comprises the following steps:

[0024] S1. Establishment of nursery pond: After the water in nursery pond is treated by sand filtration, activated carbon and mesh filtration, the water bacteria phase is added for regulation, and the amount added is 2L / m 3 The bacterial phase of the pool water was lactic acid bacteria, Rhodopseudomonas palustris and Nitrosobacter in a mass ratio of 1:0.2:0.5, and the concentration of lactic acid bacteria was 150×10 4 cfu / mL, the concentration of Rhodopseudomonas palustris was 100×10 4 cfu / mL, the concentration of Nitrosobacter eutropha was 250×10 4 cfu / mL;

[0025] S2. Water quality control: control the light intensity to 2000Lx, temperature to 26℃, pH value to 6.0;

[0026] S3. Stocking: Select disease-free, healthy shrimp fry with a body length of 1.1 cm, and stock at a density of 80,000 / m 2 Put the shrimp fry into the nursery pond and feed them with starter feed 10% of the shrimp fry weight 3 to 5 times a day;

[0027] S4. Cultivation: When the above shrimp fry develop into larvae, remove them and transfer them to the cultivation pond. Adjust the light intensity to 1200lx, control the water temperature to 27℃, salinity to 26‰, pH to 8, and aerate at 36L / m per hour. 3 The aeration volume is increased, the aquaculture wastewater is replaced every day, and the water replacement volume is increased by 10% of the initial daily water replacement volume. Artificial feed is added every day according to 35% of the weight of shrimp fry. The artificial feed includes the following raw materials in parts by weight: 2 parts of cod liver oil, 0.1 parts of vitamin C, 0.2 parts of microbial polysaccharides, 0.3 parts of ginsenosides, and 1.3 parts of xylanase. The microbial polysaccharides are composed of pullulan α-glucan, Monascus polysaccharide, and Flavobacterium gum in a mass ratio of 3:1:5. It is fed twice a day to dilute the fry.

[0028] Example 2

[0029] A method for raising shrimp seedlings to effectively improve their disease resistance comprises the following steps:

[0030] S1. Establishment of nursery pond: After the water in nursery pond is treated by sand filtration, activated carbon and mesh filtration, the water bacteria phase is added for regulation, and the amount added is 5L / m 3 The bacterial phase of the pool water was lactic acid bacteria, Rhodopseudomonas palustris and Nitrosobacter in a mass ratio of 3:0.8:1.2, and the concentration of lactic acid bacteria was 180×10 4 cfu / mL, the concentration of Rhodopseudomonas palustris was 200×10 4 cfu / mL, the concentration of Nitrosobacter eutropha was 380×10 4 cfu / mL;

[0031] S2. Water quality control: light intensity is controlled at 45000Lx, temperature at 28℃, pH value at 8.5;

[0032] S3. Stocking: Select disease-free, healthy shrimp fry with a body length of 2.5 cm, and stock at a density of 120,000 / m 2 Put the shrimp fry into the nursery pond and feed them 50% of the shrimp fry weight 5 times a day;

[0033] S4. Cultivation: When the above shrimp fry develop into larvae, remove them and transfer them to the cultivation pond. Adjust the light intensity to 2800lx, control the water temperature to 33℃, salinity to 33‰, pH to 8.3, and aerate at 45L / m per hour. 3 The aeration volume is set, the aquaculture wastewater is replaced every day, and the water change volume is increased from 10% to 50% of the initial daily water change volume. Artificial feed is added every day according to 60% of the weight of the shrimp fry. The artificial feed includes the following raw materials in parts by weight: 5 parts of cod liver oil, 0.9 parts of vitamin C, 0.5 parts of microbial polysaccharides, 0.8 parts of ginsenosides, and 2.5 parts of xylanase. The microbial polysaccharides are composed of pullulan α-glucan, Monascus polysaccharide, and Flavobacterium gum in a mass ratio of 5:2:5. It is fed 4 times a day to dilute the fry.

[0034] Example 3

[0035] A method for raising shrimp seedlings to effectively improve their disease resistance includes the following steps:

[0036] S1. Establishment of nursery pond: After the water in nursery pond is treated by sand filtration, activated carbon and mesh filtration, the water bacteria phase is added for regulation, and the amount added is 2-5L / m 3 The bacterial phase of the pool water was lactic acid bacteria, Rhodopseudomonas palustris and Nitrosobacter in a mass ratio of 2:0.6:0.8, and the concentration of lactic acid bacteria was 160×10 4 cfu / mL, the concentration of Rhodopseudomonas palustris was 150×10 4 cfu / mL, the concentration of Nitrosobacter eutropha was 320×10 4 cfu / mL;

[0037] S2. Water quality control: control the light intensity to 28000Lx, temperature to 27℃, pH value to 7.2;

[0038] S3. Stocking: Select disease-free, healthy shrimp fry with a body length of 2 cm, and stock at a density of 100,000 / m 2 Put the shrimp fry into the nursery pond and feed them with starter feed 30% of the shrimp fry weight 4 times a day;

[0039] S4. Cultivation: When the above shrimp fry develop into larvae, remove them and transfer them to the cultivation pond. Adjust the light intensity to 2000lx, control the water temperature to 30℃, salinity to 29‰, pH8, and aerate at 41L / m per hour. 3 The aeration volume is increased, the aquaculture wastewater is replaced every day, and the water replacement volume is increased by 30% of the initial daily water replacement volume. Artificial feed is added every day according to 50% of the weight of shrimp fry. The artificial feed includes the following raw materials in weight: 3 parts of cod liver oil, 0.5 parts of vitamin C, 0.3 parts of microbial polysaccharides, 0.5 parts of ginsenosides, and 2.0 parts of xylanase. The microbial polysaccharides are composed of pullulan α-glucan, Monascus polysaccharide, and Flavobacterium gum in a mass ratio of 4:1.3:5. It is fed 3 times a day to dilute the fry.

[0040] Comparative Example 1

[0041] The difference between this comparative example and Example 3 is that the S1 does not put pond water bacteria into the nursery pond during the establishment of the nursery pond; specifically, a nursery method for effectively improving the disease resistance of shrimp fry includes the following steps:

[0042] S1. Establishment of nursery pond: The water in nursery pond is treated by sand filtration, activated carbon and screen filtration;

[0043] S2. Water quality control: control the light intensity to 28000Lx, temperature to 27℃, pH value to 7.2;

[0044] S3. Stocking: Select disease-free, healthy shrimp fry with a body length of 2 cm, and stock at a density of 100,000 / m 2 Put the shrimp fry into the nursery pond and feed them with starter feed 30% of the shrimp fry weight 4 times a day;

[0045] S4. Cultivation: When the above shrimp fry develop into larvae, remove them and transfer them to the cultivation pond. Adjust the light intensity to 2000lx, control the water temperature to 30℃, salinity to 29‰, pH8, and aerate at 41L / m per hour. 3 The aeration volume is increased, the aquaculture wastewater is replaced every day, and the water replacement volume is increased by 30% of the initial daily water replacement volume. Artificial feed is added every day according to 50% of the weight of shrimp fry. The artificial feed includes the following raw materials in weight: 3 parts of cod liver oil, 0.5 parts of vitamin C, 0.3 parts of microbial polysaccharides, 0.5 parts of ginsenosides, and 2.0 parts of xylanase. The microbial polysaccharides are composed of pullulan α-glucan, Monascus polysaccharide, and Flavobacterium gum in a mass ratio of 4:1.3:5. It is fed 3 times a day to dilute the fry.

[0046] Comparative Example 2

[0047] The difference between this comparative example and Example 3 is that the bacteria in the pond water contain lactic acid bacteria, Rhodopseudomonas palustris and Nitrosobacter at a mass ratio of 5:0.1:1. Specifically, a method for raising shrimp seedlings to effectively improve the disease resistance of shrimp seedlings comprises the following steps:

[0048] S1. Establishment of nursery pond: After the water in nursery pond is treated by sand filtration, activated carbon and mesh filtration, the water bacteria phase is added for regulation, and the amount added is 2-5L / m 3 The bacterial phase of the pond water was lactic acid bacteria, Rhodopseudomonas palustris and Nitrosobacter in a mass ratio of 5:0.1:1, and the concentration of lactic acid bacteria was 160×10 4 cfu / mL, the concentration of Rhodopseudomonas palustris was 150×10 4 cfu / mL, the concentration of Nitrosobacter eutropha was 320×10 4 cfu / mL;

[0049] S2. Water quality control: control the light intensity to 28000Lx, temperature to 27℃, pH value to 7.2;

[0050] S3. Stocking: Select disease-free, healthy shrimp fry with a body length of 2 cm, and stock at a density of 100,000 / m 2 Put the shrimp fry into the nursery pond and feed them with starter feed 30% of the shrimp fry weight 4 times a day;

[0051] S4. Cultivation: When the above shrimp fry develop into larvae, remove them and transfer them to the cultivation pond. Adjust the light intensity to 2000lx, control the water temperature to 30℃, salinity to 29‰, pH8, and aerate at 41L / m per hour. 3The aeration volume is increased, the aquaculture wastewater is replaced every day, and the water replacement volume is increased by 30% of the initial daily water replacement volume. Artificial feed is added every day according to 50% of the weight of shrimp fry. The artificial feed includes the following raw materials in weight: 3 parts of cod liver oil, 0.5 parts of vitamin C, 0.3 parts of microbial polysaccharides, 0.5 parts of ginsenosides, and 2.0 parts of xylanase. The microbial polysaccharides are composed of pullulan α-glucan, Monascus polysaccharide, and Flavobacterium gum in a mass ratio of 4:1.3:5. It is fed 3 times a day to dilute the fry.

[0052] Comparative Example 3

[0053] The difference between this comparative example and Example 3 is that the artificial bait in S3 includes the following raw materials by weight: 6 parts of cod liver oil, 0.1 parts of vitamin C, 0.8 parts of microbial polysaccharides, 0.1 parts of ginsenosides, and 1 part of xylanase; specifically, a method for raising shrimp seedlings to effectively improve their disease resistance includes the following steps:

[0054] S1. Establishment of nursery pond: After the water in nursery pond is treated by sand filtration, activated carbon and mesh filtration, the water bacteria phase is added for regulation, and the amount added is 2-5L / m 3 The bacterial phase of the pool water was lactic acid bacteria, Rhodopseudomonas palustris and Nitrosobacter in a mass ratio of 2:0.6:0.8, and the concentration of lactic acid bacteria was 160×10 4 cfu / mL, the concentration of Rhodopseudomonas palustris was 150×10 4 cfu / mL, the concentration of Nitrosobacter eutropha was 320×10 4 cfu / mL;

[0055] S2. Water quality control: control the light intensity to 28000Lx, temperature to 27℃, pH value to 7.2;

[0056] S3. Stocking: Select disease-free, healthy shrimp fry with a body length of 2 cm, and stock at a density of 100,000 / m 2 Put the shrimp fry into the nursery pond and feed them with starter feed 30% of the shrimp fry weight 4 times a day;

[0057] S4. Cultivation: When the above shrimp fry develop into larvae, remove them and transfer them to the cultivation pond. Adjust the light intensity to 2000lx, control the water temperature to 30℃, salinity to 29‰, pH8, and aerate at 41L / m per hour. 3 The aeration volume is increased, the aquaculture wastewater is replaced every day, and the water change volume is increased by 30% of the initial daily water change volume. Artificial feed is added every day according to 50% of the weight of shrimp fry. The artificial feed includes the following raw materials in weight: 6 parts of cod liver oil, 0.1 parts of vitamin C, 0.8 parts of microbial polysaccharides, 0.1 parts of ginsenosides, and 1 part of xylanase. The microbial polysaccharides are composed of pullulan α-glucan, Monascus polysaccharide, and Flavobacterium gum in a mass ratio of 4:1.3:5. It is fed 3 times a day to dilute the fry.

[0058] 1. Determination of enzyme activity related to disease resistance

[0059] The adult shrimps cultured in the above Examples 1 to 3 and Comparative Examples 1 to 3 were divided into 6 groups, each with 10 to 15 shrimps.

[0060] (1) Blood cell count: Use a BCG syringe and a No. 7 needle to collect blood from the heart of the shrimp, use 10% formalin as a fixative (fixative: blood = 1:1), put it into a centrifuge tube and mix well, and count the blood cells under a light microscope.

[0061] (2) Blood was collected from the heart using a syringe and placed in a centrifuge tube. The tube was kept at 4°C for several hours. The blue serum was taken out and stored at -20°C for later use. The serum protein content of shrimp was determined according to the Comassic brilliant blue method.

[0062] Protein content (mg / mL) = (OD of test tube / OD of standard tube) × standard serum concentration

[0063] (3) Lytic activity (LSZ) The secondary activated lysodeiktic micrococci were inoculated into beef extract peptone solid medium and cultured for 48 h. The cells were collected by centrifugation and then diluted to A with 0.1 mol / L potassium phosphate buffer (pH = 6.4). 570nm =0.3, prepared into substrate suspension for testing,

[0064] Lysozyme activity (U / mL) = (A0-A) / A0

[0065] (4) The antibacterial activity was determined by using Vibrio as the substrate and diluting the solution to A with 0.1 mol / L potassium phosphate buffer (pH = 6.4). 570nm =0.3, antibacterial activity = [(A0-A) / A0] 1 / 2

[0066] (5) The activity of superoxide dismutase (SOD) was determined by the pyrogallol autooxidation method.

[0067] (6) The activity of phenol oxidase (PO) was determined by a colorimetric method using L-dopa as a substrate.

[0068]

[0069] From the above results, it can be seen that the shrimp seedling raising method of the present invention can improve the enzyme activity related to the disease resistance of shrimp. The present invention significantly improves the lysozyme activity in the serum of shrimp and increases the phenoloxidase by adjusting the water quality, adding the bacterial phase and scientifically preparing the bait, and can perform immune recognition and epidemic prevention on the zymogen activation during the invasion of foreign pathogens and environmental stress, thereby improving the disease resistance of shrimp.

[0070] 2. Taura virus challenge test

[0071] In Examples 1 to 3 and Comparative Examples 1 to 3, 20 shrimps were randomly selected for the challenge test, and the median lethal concentration (LD50) of the Taura virus to Penaeus vannamei was determined by preliminary tests. 50 )(5d) is 2.96×10 8 CFU / mL. Inject 30 μL of this concentration of bacterial solution into the back of the 2nd to 3rd abdominal segment of the shrimp. Count the number of deaths on day 7 and calculate the cumulative mortality rate.

[0072] Cumulative mortality rate = cumulative number of deaths / initial number × 100%

[0073]

[0074] The virus attack test of this experiment shows that the seedling cultivation method of the present invention can enhance the disease resistance of the body, effectively stimulate immune cells, and effectively resist the taura virus.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for raising shrimp seedlings to effectively improve their disease resistance, characterized in that: The following steps are involved: S1. Establishment of nursery pond: After the nursery pond water is treated by sand filtration, activated carbon and mesh filtration, the pond water bacteria phase is added for adjustment. The pond water bacteria phase is lactic acid bacteria, Rhodopseudomonas palustris and Nitrosobacter in a mass ratio of 1-3:0.2-0.8:0.5-1.2; S2. Water quality control: control the light intensity to 2000-45000Lx, temperature to 26-28℃, pH value to 6.0-8.5; S3. Stocking: Select disease-free, healthy shrimp fry with a body length of 1.1 to 2.5 cm, and stock at a density of 80,000 to 120,000 shrimp / m 2 Put the shrimp fry into the nursery pond and feed them 10-50% of the shrimp fry weight 3-5 times a day; S4. Cultivation: When the above shrimp fry develop into larvae, remove them and transfer them to the cultivation pond. Adjust the light intensity to 1200lx-2800lx, control the water temperature to 27-33℃, salinity to 26‰-33‰, pH to 8-8.3, and aerate at 36-45L / m per hour. 3 The aeration volume is increased by 10-50% of the initial daily water replacement volume, and artificial feed is added at 35-60% of the weight of shrimp fry every day, 2-4 times a day, to dilute the fry; The artificial bait in S4 comprises the following raw materials in parts by weight: 2-5 parts of cod liver oil, 0.1-0.9 parts of vitamin C, 0.2-0.5 parts of microbial polysaccharides, 0.3-0.8 parts of ginsenosides, and 1.3-2.5 parts of biological enzymes.

2. A method for raising shrimp seedlings to effectively improve disease resistance according to claim 1, characterized in that: The concentration of the lactic acid bacteria is (150-180)×10 4 cfu / mL, the concentration of Rhodopseudomonas palustris is (100~200)×10 4 cfu / mL, the concentration of Nitrosobacter eutropha is (250~380)×10 4 cfu / mL.

3. A method for raising shrimp seedlings to effectively improve disease resistance according to claim 2, characterized in that: The amount of bacteria in S1 is 2-5 L / m 3 .

4. A method for raising shrimp seedlings to effectively improve disease resistance according to claim 1, characterized in that: The open-mouthed bait in S3 is 2-3 parts of S-type rotifers, 0.5-1 parts of medium-sized rotifers and 0.2-0.5 parts of copepod nauplii.

5. A method for raising shrimp seedlings to effectively improve disease resistance according to claim 1, characterized in that: The microbial polysaccharide consists of pullulan alpha-glucan, monascus polysaccharide and flavobacterium gum in a mass ratio of 3-5:1-2:

5.

6. A method for raising shrimp seedlings to effectively improve disease resistance according to claim 1, characterized in that: The biological enzyme is one or a combination of xylanase, lipase, cellulase, mannanase, protein complex enzyme, amylase and xanthan gum lyase.

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