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

Abstract

The present application relates to a kind of concentrated frozen chlorella applied to the method of south American white prawn breeding in, belong to the technical field of breeding, comprising the following steps: concentrated frozen chlorella under-20 ℃ condition is transferred to 0~4 ℃ condition and is stored;In 0~4 ℃ condition, the concentrated frozen chlorella is completely thawed to obtain concentrated chlorella;Before 2~8h, the concentrated chlorella obtained after thawing is pretreated by being sprinkled with concentrated chlorella in the breeding pond: the treatment mode of pretreatment is to take concentrated chlorella and seawater mixed in the light container to form mixed solution, add bacteria to mixed solution, then add fermentation carbon source to obtain algal liquid by fermentation.The present application is pretreated before use to concentrated frozen chlorella, to solve the problem that concentrated frozen chlorella is seriously dirty in south American white prawn breeding, water quality index is difficult to control, and the survival rate of breeding is low.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of seedling culture, and particularly relates to a method for applying concentrated frozen chlorella to seedling culture of south American white prawn. BACKGROUND

[0002] Algae is a kind of widely distributed and nutritionally rich microorganism, usually containing 30%-60% of protein, 10%-20% of fatty acid and 5%-15% of carbohydrate, and rich in EPA, ARA and DHA and other polyunsaturated fatty acids, which plays an important role in the development of juvenile and is indispensable in the seedling culture of fish, shrimp, crab, shellfish and other aquatic animals.

[0003] Chlorella vulgaris is a kind of spherical single-cell freshwater algae with rich protein content, complete amino acid types and standard model proportion, and multiple vitamins, and is a kind of excellent single-cell protein source and can be used as bait.

[0004] In July 1988, south American white prawn was introduced into China from Hawaii, USA by China Ocean Institute, and the artificial seedling culture technology was also introduced at the same time. The prawn seedling culture industry in China started at that time, and has been developed for more than 30 years, and has been quite large in scale. The production area is concentrated in the southeast coast. In 2023, the seedling culture amount of south American white prawn in China is 1.30 billion, and the seedling culture link is the primary link of the value chain of south American white prawn. The quality of seedling directly affects the value realization ability and profit distribution of participants in subsequent links. In this link, the quality of parent prawn and the cultivation technology are related to the quality of prawn seedling and the value-added ability of the seedling culture link, and are the key to the success or failure of the subsequent breeding link. Since the juvenile has high sensitivity to the water environment, the water quality regulation, feed feeding, salinity and temperature will all affect the quality and survival rate of prawn seedling. Among them, microalgae feed as the first feed after the opening of the juvenile is particularly important in the seedling culture process.

[0005] At present, in the shrimp breeding, microalgae bait is generally fed with fresh algae. But fresh algae is often not supplied in time, which is out of sync with the breeding progress, and it is difficult to meet the demand for fresh bait in the breeding. In addition, the breeding field needs to be equipped with algae culture room and high-tech algae culture personnel, which is complex in operation and high in cost. Although the frozen concentrated algae (0~4℃) can alleviate the problem of supply disconnection, its storage time is limited. If the frozen concentrated algae is not detected in time and applied to the breeding pond, it will cause the water quality to deteriorate and the survival rate of the breeding to be very low, which not only increases the management difficulty but also reduces the success rate of the breeding. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a method for applying concentrated frozen chlorella to the breeding of white shrimp.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a method for applying concentrated frozen chlorella to the breeding of white shrimp, comprising the following steps:

[0008] S1, transferring the concentrated frozen chlorella under the condition of-20℃ to the condition of 0~4℃ for storage;

[0009] S2, under the condition of 0~4℃, the concentrated frozen chlorella is completely melted to obtain concentrated chlorella;

[0010] S3, 2~8h before the concentrated chlorella is sprinkled into the breeding pond, the concentrated chlorella obtained after melting is pretreated: the pretreatment method is to mix the concentrated chlorella obtained after melting with seawater in a clean container with good light transmission to form a mixed solution, add bacteria to the mixed solution, and then add a fermentation carbon source to obtain an algae liquid.

[0011] Further, in step S2, the concentrated chlorella stored at 0~4℃ needs to be used within 2 days.

[0012] Further, in step S2, when a part of the concentrated chlorella completely melted and stored at 0~4℃ is taken out for use, the remaining part is put back into the storage at 0~4℃ within 5min after the required volume is taken out.

[0013] Further, in step S3, the fermentation process is always in a boiling and aerated state, the temperature is maintained at 25~30℃, the light illumination is maintained at 1000~5000lx, and the fermentation time is 2~6h.

[0014] Further, in step S3, the volume ratio of the concentrated nannochloropsis to seawater is 1:10-100; the volume ratio of the bacterial body to the concentrated nannochloropsis is 1:2-10; and the mass ratio of the fermentation carbon source to the concentrated nannochloropsis is 1:20-100.

[0015] Further, in step S3, the bacterial body comprises one or more of lactic acid bacteria, bacillus, yeast and photosynthetic bacteria.

[0016] Further, in step S3, the fermentation carbon source is glucose.

[0017] Further, in step S3, the algal liquid is filtered by filter cotton, and the filtered algal liquid is evenly sprayed into the rearing pond for use.

[0018] The present application has the following advantages:

[0019] The present application solves the problems of serious dirtiness, difficult control of water quality indexes and low survival rate of nannochloropsis in the rearing of South American white prawns by pretreating the concentrated frozen nannochloropsis before use, and has the advantages of easy availability and preservation of raw materials, easy control of treatment conditions, simple use equipment, easy operation and good application effect. BRIEF DESCRIPTION OF DRAWINGS

[0020] The advantages and implementation modes of the present application will be more obvious by referring to the accompanying drawings and combining the examples, wherein the contents shown in the drawings are only used for explaining the present application and do not constitute any limitation on the present application, and in the drawings:

[0021] Figure 1 The present application is a comparison of the photos of each group in the pretreatment experiment 1.

[0022] Figure 2 The present application is a comparison of the photos of each group in the pretreatment experiment 2.

[0023] Figure 3 The present application is a comparison of the photos of each group in the pretreatment experiment 3. DETAILED DESCRIPTION

[0024] In order to make the person skilled in the art better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the drawings and the best embodiment.

[0025] A method for applying concentrated frozen nannochloropsis to the rearing of South American white prawns, comprising the following steps:

[0026] S1, before use for rearing, the concentrated frozen nannochloropsis under-20℃ is transferred to 0-4℃ for storage;

[0027] Specifically, according to the seedling use amount plan, the purchased concentrated frozen Chlorella zofnigii is sub-packed into each bag of 1-5L and stored at-20℃; then the frozen concentrated Chlorella zofnigii meeting the use amount of 1-2 days is transferred from-20℃ to 4℃ for storage.

[0028] S2, the concentrated Chlorella zofnigii obtained after complete thawing is used up within 2 days at 0-4℃;

[0029] Specifically, the concentrated Chlorella zofnigii that has been thawed and stored at 4℃ is taken as standby, wherein the concentrated Chlorella zofnigii that has been completely thawed and stored at 4℃ needs to be used up within 2 days.

[0030] When a part of the concentrated Chlorella zofnigii that has been completely thawed and stored at 4℃ needs to be taken out for use, the remaining part should be put back to storage at 4℃ within 5min after the required volume is taken out.

[0031] The concentrated Chlorella zofnigii that has been completely thawed and stored at 4℃ is subjected to process detection, and if it is still not spoiled after 2 days, it can be continuously used, otherwise it cannot be continuously used.

[0032] S3, the concentrated Chlorella zofnigii obtained after thawing is pretreated 2-8h before being splashed into the seedling pond.

[0033] Specifically, the pretreatment is mixing the concentrated Chlorella zofnigii obtained after thawing with seawater (clean seawater) in a clean container with good light transmission to form a mixed solution (the volume ratio of concentrated Chlorella zofnigii to clean seawater is 1:10-100), adding bacteria (the volume ratio of bacteria to concentrated Chlorella zofnigii is 1:2-10) to the mixed solution, wherein the bacteria include one or more of lactic acid bacteria, bacillus, yeast and photosynthetic bacteria, and then adding a fermentation carbon source (glucose) to obtain an algae liquid (the mass ratio of fermentation carbon source to concentrated Chlorella zofnigii is 1:20-100), wherein the fermentation process is always in a boiling and aerated state, the temperature is kept at 25-30℃, the light is kept at 1000-5000lx, and the fermentation time is 2-6h.

[0034] Specifically, the pretreatment is mixing 0.5-2L of the concentrated Chlorella zofnigii obtained after thawing with 20-50L of clean seawater in a clean container with good light transmission to form a mixed solution, adding 0.2-1L of one or more of lactic acid bacteria, bacillus, yeast and photosynthetic bacteria to the mixed solution, and then adding 20-100g of a fermentation carbon source (glucose) to obtain an algae liquid, wherein the fermentation process is always in a boiling and aerated state, the temperature is kept at 25-30℃, the light is kept at 1000-5000lx, and the fermentation time is 2-6h.

[0035] When algae solution is needed, take the required amount and filter it with filter cotton. Then, evenly sprinkle the filtered algae solution into the seedling pond for use.

[0036] Due to existing concentration methods, Chlorella often breaks down after concentration. Furthermore, the thawing process before use can also cause Chlorella to break down. Broken Chlorella produces soluble organic matter, which, if not removed before application to the nursery pond, can lead to algae clumping, shrimp larvae becoming easily soiled, water quality deterioration, and low nursery success rates. This application aims to dilute the thawed concentrated Chlorella to a certain density and use bacterial fermentation to remove harmful substances from the concentrated Chlorella, thereby solving the problems associated with concentrated frozen Chlorella in the nursery of Litopenaeus vannamei.

[0037] Pretreatment Experiment 1:

[0038] As shown in Table 1, three 250mL conical-bottom glass containers were selected and labeled as Group 1, Group 2, and Group 3. 5mL of concentrated Chlorella (obtained by thawing frozen Chlorella) and 195mL of clean seawater with a salinity of 30‰ were added to Groups 1, 2, and 3, respectively. Aeration tubes were then added, and the aeration rate was adjusted. Additionally, 2.5mL of photosynthetic bacteria and 0.5mL of fermentation carbon source were added to Group 1 and Group 2, respectively. Each group was aerated for 24 hours at room temperature (27℃).

[0039] Table 1 Components of each group in the pretreatment experiment

[0040]

[0041] like Figure 1 As shown, after 5 minutes of gas deprivation, the condition of each group was observed. Flocculent matter appeared at the bottom of the bottle in the third group, while no flocculent matter appeared in the first and second groups. This indicates that flocculent matter will appear after the melted concentrated Chlorella is aerated with water without the addition of bacteria.

[0042] Pretreatment Experiment 2:

[0043] Experimental Group 1: After thawing concentrated frozen Chlorella, 500 mL was placed in a 10 mL container. 3 Aeration in water.

[0044] Experimental Group 2: 500 mL of concentrated frozen Chlorella was thawed and pretreated (e.g., 500 mL of the thawed concentrated Chlorella was mixed with 20 L of clean seawater in a clean container with good light transmittance to form a mixture; 250 mL of lactic acid bacteria, Bacillus, yeast, and photosynthetic bacteria were added to the mixture, followed by 50 g of glucose for fermentation to obtain algal liquid; the fermentation process was carried out in a boiling aeration state, maintaining a temperature of 28℃ and a light intensity of 3000 lx for 6 hours; the fermented algal liquid was then filtered). The mixture was then placed in a 10 mL container.3 Aeration in water.

[0045] like Figure 2 As shown, filamentous algae aggregates adhered to the pool wall in experimental group one, while no such phenomenon was observed in the pool wall of experimental group two.

[0046] Pretreatment Experiment 3:

[0047] Control group: Fresh seaweed was used.

[0048] Experimental Group 1: Concentrated frozen Chlorella was used.

[0049] The second experimental group used pretreated frozen concentrated Chlorella (for example, 1000ml of concentrated Chlorella obtained after melting was mixed with 40L of clean seawater in a clean container with good light transmission to form a mixture. 500ml of lactic acid bacteria, Bacillus, yeast and photosynthetic bacteria were added to the mixture, and then 100g of glucose was added for fermentation to obtain algal liquid. The fermentation process was carried out in a boiling aeration state, the temperature was maintained at 28℃, the light intensity was maintained at 3000lx, the fermentation time was 6h, and the fermented algal liquid was filtered).

[0050] Prepare three 20m 3 The nursery ponds were designated as the control group, the first experimental group, and the second experimental group. Each nursery pond contained 6.5 million N5 stage Litopenaeus vannamei larvae for incubation and rearing. The temperature was not controlled during the rearing process and varied with the air temperature, ranging from 27 to 31°C. Each group was fed the same feed every 6 hours at the same density. Algae feeding was stopped when the larvae entered the M1 stage. The experiment proceeded to the P5 stage, and water quality indicators (ammonia nitrogen, nitrite, pH, etc.), larval status (staining, metamorphosis time), and P5 rearing success rate were examined from the start of rearing to the M1 stage.

[0051] Table 2. Data of various indicators during the seedling raising process in the control group.

[0052]

[0053] Table 3 Data on various indicators during the seedling cultivation process of the first experimental group

[0054]

[0055] Table 4. Data on various indicators during the seedling cultivation process of the second experimental group.

[0056]

[0057] like Figure 3Compared with Table 2 to Table 4, the metamorphosis time of the control group using fresh algal liquid is normal, and can reach 1 period of metamorphosis per day. The ammonia nitrogen and sub-salt in the water quality index during the process of using fresh algal liquid to breed larvae also exist the rising condition, which may be the reason why the survival rate is slightly lower than that of the second experimental group. The first experimental group, the ammonia nitrogen and sub-salt index began to rise from the second day after feeding algae, and when Z1 period changed to Z2 period, the metamorphosis time was delayed for one day. From Z2 period, the larvae were seriously dirty, which led to the metamorphosis of Z3 period and M1 period not smooth, the metamorphosis time was long, and finally also led to the low survival rate of the larvae, only 15%. The second experimental group, compared with the data of the control group, the larvae from Z1 period to Z2 period took a little longer time, which may be related to the type of the breeding algae used. Compared with the first experimental group, the second experimental group basically had no dirt during the process of breeding larvae, the water quality index was better, and the survival rate was also higher, reaching 47%.

[0058] The above describes the embodiments of the present application in detail, but the content described is only the preferred embodiments of the present application, and cannot be considered to limit the implementation scope of the present application. Any equivalent changes and improvements made within the scope of the present application should still belong to the scope covered by the present application.

Claims

1. A method for applying concentrated frozen Chlorella to the breeding of Litopenaeus vannamei, characterized in that: Includes the following steps: S1. Transfer the concentrated frozen Chlorella at -20℃ to a storage environment of 0~4℃; S2. Under conditions of 0~4℃, the concentrated frozen Chlorella is completely melted to obtain concentrated Chlorella; S3. 2-8 hours before sprinkling concentrated Chlorella into the seedling 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 mixture, add bacteria to the mixture, and then add a fermentation carbon source to ferment and obtain algal liquid. In step S3, the fermentation process is in a boiling aeration state, the temperature is maintained at 25~30℃, the light intensity is maintained at 1000~5000lx, and the fermentation time is 2~6h. In step S3, the bacterial cells include one or more of lactic acid bacteria, Bacillus, yeast, and photosynthetic bacteria.

2. The method for applying concentrated frozen Chlorella to the breeding of Litopenaeus vannamei according to claim 1, characterized in that: In step S2, the concentrated Chlorella stored at 0~4℃ must be used within 2 days.

3. The method for applying concentrated frozen Chlorella to the breeding of Litopenaeus vannamei according to claim 1, characterized in that: In step S2, when a portion of the concentrated Chlorella that has been completely melted at 0~4℃ needs to be taken out for use, the remaining portion should be returned to the 0~4℃ condition for storage within 5 minutes after the required volume is taken out.

4. The method for applying concentrated frozen Chlorella to the breeding of Litopenaeus vannamei 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.

5. The method for applying concentrated frozen Chlorella to the breeding of Litopenaeus vannamei according to claim 1, characterized in that: In step S3, the fermentation carbon source is glucose.

6. The method for applying concentrated frozen Chlorella to the breeding of Litopenaeus vannamei according to claim 1, characterized in that: In step S3, the algae solution is filtered with filter cotton, and the filtered algae solution is evenly sprinkled into the seedling pond for use.

Images