Method for applying concentrated frozen chlorella to breeding of penaeus vannamei boone

Abstract

The invention relates to a method for applying concentrated frozen chlorella to breeding of penaeus vannamei boone, which belongs to the technical field of breeding and comprises the following steps: transferring the concentrated frozen chlorella at the temperature of-20 DEG C to the temperature of 0-4 DEG C for preservation; under the condition of 0-4 DEG C, the concentrated frozen chlorella is completely melted to obtain concentrated chlorella; 2-8 hours before the concentrated chlorella is splashed into the nursery pond, the concentrated chlorella obtained after melting is subjected to pretreatment, and the pretreatment comprises the steps that the concentrated chlorella and seawater are mixed in a light-transmitting container to form a mixed solution, thalli are added into the mixed solution, then a fermentation carbon source is added for fermentation, and the chlorella solution is obtained. According to the method, the concentrated and frozen chlorella is pretreated before use, so that the problems that the concentrated and frozen chlorella is severely dirty, the water quality index is difficult to control and the survival rate of breeding is low in the breeding process of the penaeus vannamei are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of seedling cultivation, and in particular relates to a method for applying concentrated frozen Chlorella to white shrimp seedling cultivation. Background Art

[0002] Algae is a widely distributed, nutrient-rich microorganism that typically contains 30% to 60% protein, 10% to 20% fatty acids and 5% to 15% carbohydrates. It is rich in polyunsaturated fatty acids such as EPA, ARA and DHA, and plays an important role in seedling development. It is indispensable in the breeding of aquatic animals such as fish, shrimp, crab and shellfish.

[0003] Chlorella (scientific name Chlorella vulgaris) is a ubiquitous single-cell green algae belonging to the Chlorophyta, Chlorellaceae, Chlorophyta. It is a spherical single-cell freshwater algae with a diameter of 3~8μm. It is rich in protein, has a full range of amino acids, and the proportions are close to the standard pattern. It also contains multiple vitamins. It is an excellent single-cell protein source and can be used as bait.

[0004] In July 1988, the Chinese Institute of Oceanography introduced white shrimp from Hawaii, the United States, to China, and also introduced artificial seedling technology. my country's shrimp seedling industry started here. After more than 30 years of development, it has become quite large, and the production area is concentrated in the southeastern coastal areas. In 2023, the domestic white shrimp seedling production will be 1.30 trillion. The seedling breeding link is the primary link in the white shrimp value chain. The quality of seedlings directly affects the value realization ability and profit distribution of participants in subsequent links. In this link, the quality of parent shrimp and cultivation technology are related to the quality of shrimp seedlings and the value-added ability of the seedling breeding link, and are the key to the success or failure of subsequent breeding links. Because the larvae are highly sensitive to the water environment, water quality control, feed feeding, salinity, temperature and other factors will affect the quality and survival rate of shrimp seedlings. Among them, microalgae bait is the first feed after the larvae open their mouths, which is particularly important in the seedling breeding process.

[0005] At present, in shrimp seedlings, microalgae bait is generally fed with fresh algae. However, fresh algae are often out of touch with the seedling progress due to untimely supply, making it difficult to meet the demand for fresh bait in seedlings. In addition, the nursery needs to be equipped with algae cultivation rooms with high-tech algae cultivation personnel, which is complicated to operate and costly. Although refrigerated concentrated algae (0~4℃) can alleviate some of the supply disconnection problems, its storage time is limited. If the refrigerated concentrated algae cannot be detected in time and applied to the seedling pond, the water quality will deteriorate, resulting in a very low survival rate of seedlings, which not only increases the difficulty of management but also reduces the success rate of seedlings. Although frozen concentrated algae (-20℃) can also alleviate the supply disconnection problem, it has poor use effect in the seedling process. During the seedling process, there are serious problems such as dirt hanging, difficult to control water quality indicators, and low survival rate of seedlings, which seriously affect the promotion and use of frozen concentrated algae in seedlings. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for applying concentrated frozen Chlorella to white shrimp seedling cultivation.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for applying concentrated frozen Chlorella to white shrimp seedlings, comprising the following steps: S1. Transfer the concentrated frozen Chlorella at -20°C to a temperature of 0-4°C for storage; S2. At 0-4° C., the concentrated frozen chlorella is completely melted to obtain concentrated chlorella; S3. 2 to 8 hours before spraying the concentrated Chlorella into the nursery pond, pre-treat the concentrated Chlorella obtained after melting: the pre-treatment method is to mix the concentrated Chlorella obtained after melting with seawater in a clean container with good light transmittance to form a mixed solution, add bacteria to the mixed solution, and then add a fermentation carbon source to ferment to obtain algae liquid.

[0008] Furthermore, in step S2, the concentrated Chlorella stored at 0-4°C needs to be used within 2 days.

[0009] Furthermore, in step S2, when a portion of the completely melted concentrated Chlorella stored at 0-4°C needs to be taken out for use, the remaining portion after the required volume is taken out is returned to the 0-4°C condition for storage within 5 minutes.

[0010] Furthermore, in step S3, the fermentation process is always in a boiling and aerated state, the temperature is maintained at 25-30°C, the light intensity is maintained at 1000-5000lx, and the fermentation time is 2-6h.

[0011] Furthermore, in step S3, the volume ratio of the concentrated Chlorella to seawater is 1:10-100; the volume ratio of the bacterial cells to the concentrated Chlorella is 1:2-10; and the mass ratio of the fermentation carbon source to the concentrated Chlorella is 1:20-100.

[0012] Furthermore, in step S3, the bacteria include one or more of lactic acid bacteria, Bacillus, yeast, and photosynthetic bacteria.

[0013] Furthermore, in step S3, the fermentation carbon source is glucose.

[0014] Furthermore, in step S3, the algae liquid is filtered with filter cotton, and the filtered algae liquid is evenly sprinkled into the nursery pond for use.

[0015] The beneficial effects of the present invention are: The invention solves the problems of serious dirt hanging, difficult control of water quality index and low survival rate of concentrated frozen chlorella in shrimp seedling cultivation by pre-treating the concentrated frozen chlorella before use. The invention has the advantages of easy acquisition and preservation of raw materials, easy control of processing conditions, simple use equipment, simple operation and good application effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples, and the advantages and implementation methods of the present invention will become more obvious. The contents shown in the accompanying drawings are only used to explain the present invention and do not constitute any limitation to the present invention in any sense. In the accompanying drawings: Figure 1 These are comparison photos of the various groups in pretreatment experiment 1 of the present invention.

[0017] Figure 2 These are comparison photos of the groups in pre-treatment experiment 2 of the present invention.

[0018] Figure 3 These are comparison photos of the groups in the pre-treatment experiment 3 of the present invention. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and the best embodiments.

[0020] A method for applying concentrated frozen Chlorella to white shrimp seedling cultivation comprises the following steps: S1. Before using the seedlings, transfer the concentrated frozen Chlorella at -20℃ to a temperature of 0~4℃ for storage; Specifically, according to the planned usage for seedling cultivation, the purchased concentrated frozen Chlorella is packaged into bags of 1 to 5 L each and then frozen and stored at -20°C; then the frozen concentrated Chlorella that meets the usage amount for 1 to 2 days is transferred from -20°C to 4°C for storage.

[0021] S2. After the concentrated frozen chlorella is completely thawed, the concentrated chlorella is obtained, and the concentrated chlorella is used up within 2 days at 0-4°C; Specifically, concentrated chlorella that has been melted and stored at 4°C is taken for later use, wherein the concentrated chlorella that has been completely melted and stored at 4°C must be used up within 2 days.

[0022] When a portion of the completely melted concentrated Chlorella stored at 4°C needs to be taken out for use, the remaining portion should be returned to 4°C within 5 minutes after the required volume is taken out.

[0023] Conduct process inspection on completely thawed concentrated Chlorella stored at 4°C. If it has not spoiled for more than 2 days, it can continue to be used. If it has spoiled, it cannot be used.

[0024] S3. 2-8 hours before spraying into the nursery pond, pre-treat the concentrated Chlorella obtained after melting: Among them, the pre-treatment method is to mix the concentrated chlorella obtained after melting with seawater (clean seawater) in a clean container with good light transmittance to form a mixed liquid (the volume ratio of concentrated chlorella to clean seawater is 1:10~100), and add bacteria to the above mixed liquid (the volume ratio of bacteria to concentrated chlorella is 1:2~10), and the bacteria include one or more of lactic acid bacteria, Bacillus, yeast, and photosynthetic bacteria; then add a fermentation carbon source (glucose) for fermentation to obtain algae liquid (the mass ratio of fermentation carbon source to concentrated chlorella is 1:20~100), the fermentation process is always in a boiling and aerated state, the temperature is maintained at 25~30℃, the light is maintained at 1000~5000lx, and the fermentation time is 2~6h.

[0025] Specifically, the pretreatment method is to take 0.5-2L of concentrated Chlorella obtained after melting and mix it with 20-50L of clean seawater in a clean container with good light transmittance to form a mixed solution, add one or more of 0.2-1L of lactic acid bacteria, 0.2-1L of Bacillus, 0.2-1L of yeast, and 0.2-1L of photosynthetic bacteria to the above mixed solution, and then add 20-100g of fermentation carbon source (glucose) to ferment to obtain algae liquid. The fermentation process is always in a boiling and aerated state, the temperature is maintained at 25-30°C, the light is maintained at 1000-5000lx, and the fermentation time is 2-6h.

[0026] When algae liquid is needed, take the required amount and filter it with filter cotton. After filtering, sprinkle the algae liquid evenly into the nursery pond for use.

[0027] Due to the existing concentration method, the chlorella will generally break after concentration, and the thawing method of concentrated frozen chlorella before use will also cause the chlorella to break. The broken chlorella will produce soluble organic matter. If these organic matter are not removed before being used in the seedling pond, it will lead to algae agglomeration, easy dirtiness of shrimp seedlings, easy deterioration of water quality, and low seedling success rate. The present application dilutes the thawed concentrated chlorella to a certain density, uses bacterial fermentation to remove harmful substances in the concentrated chlorella, thereby achieving the purpose of solving the problems of concentrated frozen chlorella in white shrimp seedling cultivation.

[0028] Pre-treatment experiment 1: As shown in Table 1, three 250 mL conical bottom glass containers were taken, marked as the first group, the second group and the third group, and 5 mL of concentrated chlorella obtained by melting concentrated frozen chlorella and 195 mL of clean seawater with a salinity of 30‰ were added to the first group, the second group and the third group, respectively, and an aeration tube was added to adjust the gas volume. In addition, 2.5 mL of photosynthetic bacteria was added to the first group, and 2.5 mL of photosynthetic bacteria and 0.5 mL of fermentation carbon source were added to the second group. Each group was aerated for 24 h at room temperature of 27 °C.

[0029] Table 1 Components of each group in the pretreatment experiment like Figure 1 As shown, after stopping the gas for 5 minutes, the situation of each group was observed. Flocs appeared at the bottom of the bottle of the third group, while no flocs appeared in the first and second groups, indicating that flocs will appear after the melted concentrated Chlorella is added with water and aerated without adding bacteria.

[0030] Pre-treatment experiment 2: Experimental group 1: After the concentrated frozen Chlorella was melted, 500 mL was placed in 10 ml 3 Aeration of water bodies.

[0031] Experimental Group 2: After the concentrated frozen Chlorella was thawed, 500 mL was taken for pretreatment (for example, 500 ml of the concentrated Chlorella obtained after thawing was mixed with 20 L of clean seawater in a clean container with good light transmittance to form a mixed solution, 250 ml of lactic acid bacteria, Bacillus, yeast and photosynthetic bacteria were added to the mixed solution, and then 50 g of glucose was added for fermentation to obtain algae liquid. The fermentation process was always in a boiling and aerated state, the temperature was maintained at 28 ° C, the light was maintained at 3000 lx, the fermentation time was 6 hours, and the fermented algae liquid was filtered), and then put into 10m 3 Aeration of water bodies.

[0032] like Figure 2As shown, there were filamentous algae aggregates attached to the pool wall in Experimental Group 1, but no such phenomenon occurred on the pool wall in Experimental Group 2.

[0033] Pre-treatment experiment 3: Control group: fresh Thalassiosira alba was used.

[0034] The first experimental group: using concentrated frozen Chlorella.

[0035] The second experimental group: using pre-treated frozen concentrated Chlorella (for example, 1000 ml of concentrated Chlorella obtained after melting was mixed with 40 L of clean seawater in a clean container with good light transmittance to form a mixed solution, 500 ml of lactic acid bacteria, Bacillus, yeast and photosynthetic bacteria were added to the above mixed solution, and then 100 g of glucose was added for fermentation to obtain algae liquid. The fermentation process was always in a boiling and aerated state, the temperature was maintained at 28°C, the light was maintained at 3000 lx, the fermentation time was 6 hours, and the fermented algae liquid was filtered).

[0036] Prepare three 20m 3 The nursery ponds were recorded as the control group, the first experimental group and the second experimental group respectively. 6.5 million N5 stage whiteleg shrimp larvae were put into each nursery pond for hatching and nursery. The temperature was not controlled during the nursery process and changed with the air temperature. The temperature range was 27-31℃. The above-mentioned feeds were fed once every 6 hours with the same feeding density. When the shrimp fry entered the M1 stage, the algae feeding was stopped and the experiment was carried out to the P5 stage. The water quality indicators (ammonia nitrogen, nitrite, pH, etc.), larval status (dirty and metamorphosis time) and P5 nursery success rate from the beginning of seeding to the M1 stage were investigated.

[0037] Table 2 Data of various indicators during the seedling raising process of the control group Table 3 Data of various indicators during the seedling raising process of the first experimental group Table 4 Data of various indicators during the seedling raising process of the second experimental group like Figure 3As shown in Tables 2 to 4, the control group used fresh algae liquid, and the metamorphosis time was normal, reaching one stage of metamorphosis per day. The ammonia nitrogen and nitrates in the water quality indicators during the seedling cultivation process using fresh algae liquid also increased, which may be the reason why the survival rate was slightly lower than that of the second experimental group. In the first experimental group, the ammonia nitrogen and nitrate indicators began to increase from the second day after feeding algae. When the Z1 stage turned into the Z2 stage, the metamorphosis time was delayed by one day. From the Z2 stage, the dirt was serious, resulting in unsmooth metamorphosis in the Z3 and M1 stages, and the metamorphosis time was long, which ultimately led to a very low survival rate of only 15%. In the second experimental group, compared with the data of the control group, the time for the larvae to transform from the Z1 stage to the Z2 stage was slightly longer, which may be related to the type of algae used for seedling cultivation. Compared with the first experimental group, the second experimental group basically had no dirt during the seedling cultivation period, the water quality indicators were also good, and the survival rate was also relatively high, reaching 47%.

[0038] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for applying concentrated frozen Chlorella to white shrimp seedling cultivation, characterized in that: The following steps are involved: S1. Transfer the concentrated frozen Chlorella at -20°C to a temperature of 0-4°C for storage; S2. Under the condition of 0-4° C., the concentrated frozen chlorella is completely melted to obtain concentrated chlorella; S3. 2 to 8 hours before spraying the concentrated Chlorella into the nursery pond, pre-treat the concentrated Chlorella obtained after melting: the pre-treatment method is to mix the concentrated Chlorella with seawater in a light-transmitting container to form a mixed solution, add bacteria to the mixed solution, and then add a fermentation carbon source to ferment to obtain algae liquid.

2. The method for applying concentrated frozen Chlorella to white shrimp seedling cultivation according to claim 1, characterized in that: In step S2, the concentrated Chlorella stored at 0-4°C needs to be used within 2 days.

3. The method for applying concentrated frozen Chlorella to white shrimp seedling cultivation according to claim 1, characterized in that: In step S2, when a portion of the completely melted concentrated Chlorella stored at 0-4°C needs to be taken out for use, the remaining portion after the required volume is taken out is returned to the 0-4°C condition for storage within 5 minutes.

4. The method for applying concentrated frozen Chlorella to white shrimp seedling cultivation according to claim 1, characterized in that: In step S3, the fermentation process is always in a boiling and aerated state, the temperature is maintained at 25-30°C, the light intensity is maintained at 1000-5000lx, and the fermentation time is 2-6h.

5. The method for applying concentrated frozen Chlorella to white shrimp seedling cultivation according to claim 1, characterized in that: In step S3, the volume ratio of the concentrated Chlorella to seawater is 1:10-100; the volume ratio of the bacterial cells to the concentrated Chlorella is 1:2-10; and the mass ratio of the fermentation carbon source to the concentrated Chlorella is 1:20-100.

6. The method for applying concentrated frozen Chlorella to white shrimp seedling cultivation according to claim 1, characterized in that: In step S3, the bacteria include one or more of lactic acid bacteria, Bacillus, yeast, and photosynthetic bacteria.

7. The method for applying concentrated frozen Chlorella to white shrimp seedling cultivation according to claim 1, characterized in that: In step S3, the fermentation carbon source is glucose.

8. The method for applying concentrated frozen Chlorella to white shrimp seedling cultivation according to claim 1, characterized in that: In step S3, the algae liquid is filtered with filter cotton, and the filtered algae liquid is evenly sprinkled into the nursery pond for use.

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