Preparation method of alginic acid degrading bacterium fermented feed of apostichopus japonicus

Abstract

The invention belongs to the technical field of preparation of fermented feeds, and discloses a preparation method of an alginic acid degrading bacterium fermented feed of apostichopus japonicus. The alginic acid is converted into the alginate oligosaccharide by fermenting the basal feed through bacillus weihaensis, so that the absorptivity and the active components of the feed are improved. According to the prepared fermented feed, the residual amount of alginic acid is reduced, the content of crude protein is increased, then the weight gain rate, the specific growth rate and the feed conversion rate of the fed stichopus japonicus are remarkably increased, and the absorption and utilization capacity of the stichopus japonicus to feed nutrient substances is improved. The activity of intestinal digestive enzymes of the stichopus japonicus and the activity of immune-related enzymes are improved. And the microbial community structure of the intestinal tract of the stichopus japonicus is obviously changed. The growth performance and the disease resistance of the stichopus japonicus are improved. The breeding cost is reduced and the environmental pollution is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fermented feed preparation, and relates to a preparation method of a fermented feed of brown alginic acid degrading bacteria of Apostichopus japonicus. BACKGROUND

[0002] Apostichopus japonicus is a common benthic echinoderm in the global ocean, inhabiting various marine environments from intertidal zones to deep seas. It is known for its rich amino acids, vitamins, and collagen, and also has important pharmacological value. As an omnivorous benthic animal, Apostichopus japonicus mainly feeds on organic detritus, microorganisms, and small algae on the seabed, and relies on the synergistic digestion of intestinal microorganisms to transport food into the mouth through tentacles. Its growth process is relatively slow, taking about 2 to 3 years from juvenile to adult, and the growth rate is affected by water temperature, feed, and breeding density.

[0003] Apostichopus japonicus prefers feed rich in polysaccharides and proteins, such as seaweed residues and benthic bacteria. Its feeding behavior shows selectivity, with a higher preference for feed with a particle diameter less than 2 mm. In addition, the feeding process of Apostichopus japonicus is closely related to the synergistic action of intestinal microorganisms. Various digestive enzymes such as amylase, cellulase, and protease exist in the intestines of Apostichopus japonicus, among which cellulase activity is relatively high and closely related to its ability to break down seaweed feed. The bacterial community in the intestine generates short-chain fatty acids and other absorbable substances through fermentation of complex polysaccharides, providing additional nutritional sources for Apostichopus japonicus, enabling it to maintain growth in a barren geological environment. This flexibility in feeding behavior and diversity of digestive enzymes not only supports the scavenger role of Apostichopus japonicus in the natural ecosystem, but also provides important evidence for feed optimization in artificial breeding. The immune protection of Apostichopus japonicus mainly relies on the innate immune system, which cooperates with body fluids and cells to combat external pathogens. The nutritional quality of feed not only directly affects the growth and health of Apostichopus japonicus, but also closely relates to its immune capacity and stress resistance. The intestinal microbial community secretes antibacterial peptides or short-chain fatty acids to regulate the local environment and limit the growth of pathogenic bacteria.

[0004] So far, the research on the nutritional needs of sea cucumbers is still in the exploratory stage, and there is a lack of perfect demand standards. Functional additive feed has high cost and poor stability, limiting its large-scale application and actual effect is not as ideal as in the laboratory. The development of eco-friendly feed is still in the experimental stage and has not been commercialized. In particular, the palatability and digestibility of plant proteins have not been completely solved. As for fermented feed, the effects of commonly used fermentation strains such as lactic acid bacteria, bacillus, and yeast vary greatly, and strains from different sources have different adaptabilities to raw materials. Fermentation temperature, humidity, time, pH, and other conditions have a significant impact on the quality of fermented feed. In the process of seedling raising, the main component of Apostichopus japonicus feed is kelp and sargassum, etc. which are rich in indigestible polysaccharides: fucoidan. Because Apostichopus japonicus itself cannot digest fucoidan, the availability of the existing feed is often low, which seriously affects the growth performance of Apostichopus japonicus, thereby affecting the breeding income. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the present application provides a preparation method of fucoidan-degrading bacteria fermented feed for Apostichopus japonicus, which comprises the following steps: Bacillus weihaiensis The fermentation of the basic feed converts fucoidan into fucoidan oligosaccharide, thereby improving the absorption rate and active components of the feed. And improve the intestinal flora structure of Apostichopus japonicus, improve the growth performance and disease resistance of Apostichopus japonicus. Reduce the cost of breeding and reduce environmental pollution.

[0006] The above-mentioned object of the present application is achieved by the following technical scheme: A preparation method of fucoidan-degrading bacteria fermented feed for Apostichopus japonicus, comprising the following steps: S1, preparing a bacterial culture medium; mixing sodium alginate, proteose peptone, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, magnesium sulfate, calcium chloride, sodium chloride and water in a certain proportion, adding them into a conical flask, sterilizing at 115-121 DEG C for 20-30 min, and cooling to obtain the bacterial culture medium, which is ready for use; S2, preparing a bacterial liquid; inoculating the bacterial culture medium prepared in step S1 with fucoidan-degrading bacteria seed liquid in a volume ratio of 1-2%, and placing it in a 37 DEG C incubator for culture; obtaining the bacterial liquid; S3, preparing a solid culture medium and fermentation; preparing a solid culture medium by mixing the basic feed and water in a certain proportion, sterilizing it, and then placing it in a sterilized conical flask; adding the bacterial liquid prepared in S2 to the solid culture medium, and inoculating the bacterial liquid at a ratio of 5-10% of the total mass of the solid culture medium; placing it in a 37 DEG C constant temperature incubator for static fermentation after sealing with a gas permeable membrane; obtaining the fermented feed; in order to avoid excessive heat accumulation and anaerobic environment, the gas permeable membrane sealing method is used.

[0007] S4, drying and crushing; drying the fermented feed obtained in step S3 to control the moisture content to 10-15%, crushing it, and then passing it through a 50-100 mesh sieve to obtain the fucoidan-degrading bacteria fermented feed.

[0008] Further, in step S1, the mass ratio of sodium alginate, proteose peptone, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, magnesium sulfate, calcium chloride, sodium chloride and water is 0.6-1.2:0.3-0.9:0.05:0.05:0.02-0.05:0.01-0.02:2.5-3:100.

[0009] Further, in step S2, the fucoidan-degrading bacteria is Bacillus weihaiensis; from China Marine Bacteria Culture Collection Center (MCCC), with the strain preservation number 1A21688.

[0010] Further, in step S2, the culture condition is as follows: 150-200 r / min, and the culture time is 24-48 h.

[0011] Further, in step S3, the base feed ingredients are as follows: per 100 g, containing kelp powder 32 g, sargassum powder 20 g, sea green powder 20 g, corn powder 6 g, broken yeast powder 5 g, fermented soybean meal 4 g, shrimp powder 4 g, vitamin premix 4 g, fish meal 3 g, scallop edge powder 2 g.

[0012] Further, in step S3, the mass / volume ratio of the base feed and water in the solid culture medium is 1:2.

[0013] Further, in step S3, the sterilization is as follows: 115-121 ℃ for 20-30 min.

[0014] Further, in step S3, the fermentation condition is as follows: fermentation at 37 ℃ for 5-9 days, and the fermentation material is dispersed by overturning 2-4 times per day during the fermentation process; the fermentation end point is determined according to the content of alginic acid in the fermented feed reaching 40-50 mg / g of dry feed.

[0015] Further, in step S4, the drying is vacuum freeze drying, and the drying procedure is as follows: -50 ℃, 5 h; -40 ℃, 5 h; -30 ℃, 5 h; -20 ℃, 5 h; -15 ℃, 5 h; -10 ℃, 4 h; -5 ℃, 4 h; 0 ℃, 3 h; 5 ℃, 3 h; 10 ℃, 1 h; 15 ℃, 2 h; 20 ℃, 2 h; 25 ℃, 1 h. The total time is 45 h.

[0016] After the base feed is prepared into the fermented feed by the method provided in the application, the following nutritional ingredient changes are obtained: the content of alginic acid is reduced from 96 mg / g of dry feed to 45 mg / g of dry feed; the crude protein is increased from 16.19±0.12% to 17.47±0.14%; the crude fat is increased from 2.48±0.36% to 3.54±0.22%; and the total sugar is reduced from 28.83±0.08% to 23.40±0.11%. The main product of the degradation of alginic acid by the alginic acid degrading bacteria is alginic oligosaccharide, and a small amount of monosaccharide and small molecule substances are also produced.

[0017] The application also claims the use of the fermented feed of the brown algae acid degrading bacteria prepared by the above preparation method in the feeding of Apostichopus japonicus. The feeding conditions are as follows: the seawater temperature is 15-18℃, the dissolved oxygen content is not less than 5 mg / L by using an air pump to supply oxygen, and the seawater is replaced every week. The dry powder of the fermented feed of the brown algae acid degrading bacteria needs to be soaked in seawater for 8-12 hours before being fed in batches, and is fed once in the morning and once in the evening. The daily feeding amount of the fermented feed of the brown algae acid degrading bacteria is 1%~3% of the total weight of the Apostichopus japonicus in the first two weeks, and then is increased to 5%. The cultivation lasts for 60 days.

[0018] The application also claims the use of the brown algae acid degrading bacteria Bacillus weihaiensis in the preparation of the fermented feed of brown algae acid suitable for Apostichopus japonicus.

[0019] Compared with the prior art, the application has the following beneficial effects: The application is fermented raw material prepared from basic feed and water in a specific ratio, inoculated with brown algae acid degrading bacteria. The absorption rate and active components are improved by fermenting the basic feed with the brown algae acid degrading bacteria, the diseases of Apostichopus japonicus are effectively prevented and treated, the growth rate is improved, and the intestinal flora structure is improved, thereby promoting the growth and development and health of Apostichopus japonicus. The fermentation feed quality is significantly improved by accurately defining the fermentation conditions and process parameters. By strictly controlling the formula ratio and culture conditions of the bacterial culture medium, the activity of the bacteria is significantly improved, which provides a key guarantee for subsequent microbial fermentation. In addition, the mass / volume ratio of the basic feed and water is strictly limited during the feed fermentation process. After fermentation, the moisture content of the feed is controlled at 10%-15% by the precise vacuum freeze-drying process (from-50℃ to 25℃ in 45 hours), which effectively retains the functional nutrients and active components. Thanks to the accurate definition of the process parameters of the application, the fermented feed prepared by the application reduces the residual amount of brown algae acid (by 53.1%), increases the crude protein content (by 1.3%), and thus significantly improves the weight gain rate (by 3.1%), the specific growth rate (by 0.05% / d), and the feed conversion rate (3.1%) of Apostichopus japonicus after feeding, and improves the Apostichopus japonicus's ability to absorb and utilize nutrients from feed. The activity of intestinal digestive enzymes of Apostichopus japonicus is improved, among which the activity of alpha-amylase is increased by 52.2%, and the activity of cellulase is increased by 25.0%. The activity of immune-related enzymes is improved, among which the activity of alkaline phosphatase is increased by 98.1%, the activity of catalase is increased by 282.5%, the activity of superoxide dismutase is increased by 53.4%, and the activity of lysozyme is increased by 433.0%. The intestinal microbial community structure of Apostichopus japonicus is significantly changed. The fermented feed prepared by the method provided by the application plays a positive role in the cultivation of Apostichopus japonicus, and provides a theoretical basis for the green and healthy cultivation of Apostichopus japonicus. BRIEF DESCRIPTION OF DRAWINGS

[0020] The application will be further described below in combination with the drawings and specific embodiments.

[0021] Figure 1 A comparison chart of neutral protease activity of Apostichopus japonicus intestinal tissue after feeding with fermented feed and basic feed prepared in Example 1.

[0022] Figure 2 A comparison chart of α-amylase activity of Apostichopus japonicus intestinal tissue after feeding with fermented feed and basic feed prepared in Example 1.

[0023] Figure 3 A comparison chart of cellulase activity of Apostichopus japonicus intestinal tissue after feeding with fermented feed and basic feed prepared in Example 1.

[0024] Figure 4 A comparison chart of catalase activity of Apostichopus japonicus coelomic fluid after feeding with fermented feed and basic feed prepared in Example 1.

[0025] Figure 5 A comparison chart of alkaline phosphatase activity of Apostichopus japonicus coelomic fluid after feeding with fermented feed and basic feed prepared in Example 1.

[0026] Figure 6 A comparison chart of total nitric oxide synthase of Apostichopus japonicus coelomic fluid after feeding with fermented feed and basic feed prepared in Example 1.

[0027] Figure 7 A comparison chart of superoxide dismutase of Apostichopus japonicus coelomic fluid after feeding with fermented feed and basic feed prepared in Example 1.

[0028] Figure 8 A comparison chart of lysozyme of Apostichopus japonicus coelomic fluid after feeding with fermented feed and basic feed prepared in Example 1.

[0029] Figure 9 A comparison chart of acid phosphatase activity of Apostichopus japonicus coelomic fluid after feeding with fermented feed and basic feed prepared in Example 1.

[0030] Figure 10 A comparison chart of Apostichopus japonicus mortality after the end of the Apostichopus japonicus challenge experiment. DETAILED DESCRIPTION

[0031] The present application will be described in detail below with specific examples, but the protection scope of the present application is not limited. Unless otherwise specified, the experimental methods used in the present application are conventional methods, and the experimental apparatus, materials, reagents, etc. used can be obtained from commercial channels.

[0032] The preparation method of the fermented feed of the brown alginic acid degrading bacteria of Apostichopus japonicus provided by the present application effectively prevents and treats the diseases of Apostichopus japonicus, improves the breeding efficiency and improves the intestinal flora structure, promotes the growth and development and health of Apostichopus japonicus.

[0033] Example 1 A preparation method of a fermentation feed for a brown alginic acid degrading bacteria suitable for Apostichopus japonicus; comprising the following steps: S1. Strain acquisition The adopted strain is a brown alginic acid degrading bacteria Bacillus weihaiensis , which is purchased from the China Marine Microbial and Algal Culture Collection Center (MCCC); the strain preservation number is 1A21688.

[0034] S2. Preparation of strain culture medium The strain culture medium formula is shown in Table One. After preparation, it is added to a 250 ml conical flask, sterilized at 121℃ for 20 min, and taken out for cooling.

[0035] Table One: Formula of brown alginic acid degrading bacteria strain culture medium S3. Preparation of bacterial solution The brown alginic acid degrading bacteria preserved in step S1 is inoculated into the conical flask (containing 100 mL of strain culture medium), and placed in a 37℃ incubator for 24 h. The bacterial solution is obtained.

[0036] S4. Preparation of basic feed The basic feed ingredients are shown in Table Two.

[0037] Table Two: Basic feed ingredients S5. Preparation of fermentation feed Take 1 L conical flask, configure solid culture medium containing 240 g of basic feed and 480 mL of water. Mix well to the extent of holding together and falling apart. Inoculate 36 mL of bacterial solution prepared in step S3 into each solid culture medium. Ferment in a 37℃ incubator for 7 days. The content of brown alginic acid in the fermentation feed is 45 mg / g of dry feed, which is the fermentation endpoint.

[0038] S6. Preservation of fermentation feed The fermentation feed prepared in step S5 is freeze-dried, passed through a 100 mesh sieve, and stored at 4℃ for use.

[0039] Test Example 1 The nutritional components of the fermentation feed prepared in Example 1 and the basic feed without fermentation are determined. The determined nutritional indicators include total sugar, crude protein, crude fat, and brown alginic acid. The determination results are shown in Table Three.

[0040] Table 3 shows that the total sugar content of fermented feed is lower than that of unfermented basal feed, which is the sugar consumed by microorganisms for growth and reproduction; the crude protein and crude fat contents are higher, but the differences are not significant; and the alginic acid content is significantly lower than that before fermentation. This indicates that fermentation can enhance the nutritional value of feed, thereby improving its quality.

[0041] Table 3. Results of Nutritional Component Determination Application Example 1 This invention develops a novel method for cultivating sea cucumber-like organisms based on alginate-degrading bacteria-fermented feed, and evaluates the effects of alginate degradation products on sea cucumber growth, immunity, and gut health. The effects of the fermented feed prepared in Example 1 on the growth, digestion, and immunity of the sea cucumber-like organisms were determined.

[0042] Juvenile sea cucumbers (purchased from Dalian Bosiao Biotechnology Co., Ltd.) were used as the research subject, with a cultivation period of 60 days. After 7 days of pre-cultivation, they were divided into a control group and an experimental group, with 3 parallel tanks in each group. Each parallel tank contained 40 juvenile sea cucumbers of similar size. The control group and the experimental group were fed with basal feed and fermented feed prepared in Example 1, respectively. At the beginning, the feed amount was 3% of the total weight of the sea cucumbers in each tank. After 20 days of feeding, the feed amount was adjusted to 5% of the weight of the sea cucumbers according to their condition. The temperature in the culture tanks was maintained at 8℃, and air was introduced into the water to ensure that the dissolved oxygen level was not lower than 6 mg / L. The water was changed every 2 days. The growth of the sea cucumbers is shown in Table 4.

[0043] As can be seen from Table 4, feeding the fermented feed prepared in Example 1 significantly increased the weight gain (WGR), specific growth rate (SGR), and feed conversion ratio (FCR) of the sea cucumber, thereby improving the growth performance of the sea cucumber.

[0044] Table 4. Growth of *Semen Aspergillus* The protein quantification (TP) assay kit (Coomassie Brilliant Blue method), α-amylase assay kit (starch-iodine colorimetric method), and cellulase (CL) test kit (colorimetric method) produced by Nanjing Jiancheng Biotechnology Research Institute, China, and the neutral protease (NP) activity assay kit produced by Sangon Biotech (Shanghai) Co., Ltd., were used to detect the protease activity, α-amylase activity, cellulase activity, and protein concentration in the intestinal tissue of *Stichopus japonicus*. The results are as follows: Figures 1-3 As shown.

[0045] Depend on Figures 1-3It can be seen that the α-amylase and cellulase activities of the experimental group of sea cucumber were significantly increased compared with those of the control group. Although the neutral protease activity of the experimental group was slightly increased compared with that of the control group, there was no significant difference. Feeding the fermented feed prepared in Example 1 can improve the digestibility of sea cucumber by enhancing the α-amylase and cellulase activities.

[0046] The following assay kits were used by Nanjing Jiancheng Biotechnology Research Institute, China: Superoxide Dismutase (SOD) Assay Kit (WST-1 method), Total Nitric Oxide Synthase (NOS) Assay Kit (colorimetric method), Acid Phosphatase (ACP) Assay Kit (microplate method), Alkaline Phosphatase (AKP) Assay Kit (microplate method), Catalase (CAT) Assay Kit (visible light method) (ammonium molybdate method), and Lysozyme (LZM) Assay Kit (turbidimetric method). The activities of superoxide dismutase, total nitric oxide synthase, acid phosphatase, alkaline phosphatase, catalase, and lysozyme in the coelomic fluid of *Stichopus japonicus* were detected. The results are as follows: Figures 4-9 As shown.

[0047] Depend on Figures 4-9 It was found that the activities of SOD, AKP, CAT, LZM, NOS, and ACP were significantly increased in the experimental group compared with the control group. This indicates that feeding the fermented feed prepared in Example 1 can increase the immune enzyme activities of SOD, AKP, CAT, LZM, NOS, and ACP in sea cucumbers, thereby enhancing their non-specific immunity.

[0048] Virus challenge experiment research From each culture tank in Application Example 1, 20 healthy sea cucumbers of similar size were selected. Three parallel tanks were set up in each group, resulting in two groups: the control group fed with basal feed and the experimental group fed with fermented feed. *Vibrio splenita* was activated and cultured on NB medium at 30℃ and 180 rpm / min. *Vibrio splenita* was added to the culture tanks at a concentration of 6 × 10⁷ CFU / mL. Seawater was changed and a new batch of *Vibrio splenita* was added every 24 hours for a 7-day inoculation period. The mortality rate of the sea cucumbers was monitored during this period, and the results are as follows: Figure 10 As shown.

[0049] Depend on Figure 10 It can be seen that the mortality rate of the control group of sea cucumbers was significantly higher than that of the experimental group fed with the fermented feed prepared in Example 1, indicating that the fermented feed prepared in Example 1 can improve the non-specific immunity of sea cucumbers, enhance their resistance to Vibrio splendid infection, and reduce the mortality rate of sea cucumbers.

[0050] The above-described embodiments are merely preferred embodiments of the present application, but are not all the embodiments that can be implemented by the present application. Any obvious modifications made by those skilled in the art to the present application without departing from the principles and spirit of the present application should be considered to fall within the scope of protection of the claims of the present application.

Claims

1. A method for preparing a feed fermented by a brown alginate-degrading bacterium of Apostichopus japonicus, comprising the following steps: S1, preparing a bacterial culture medium; mixing sodium alginate, proteose peptone, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, magnesium sulfate, calcium chloride, sodium chloride, agar powder and water in a proportion, adding them into a conical flask, sterilizing at 115-121 ℃ for 20-30 min, and obtaining the bacterial culture medium after cooling; S2, preparing a bacterial solution; inoculating the bacterial culture medium obtained in step S1 with a seed solution of the brown alginate-degrading bacterium at a volume ratio of 1-2%, and culturing in a 37 ℃ incubator; obtaining the bacterial solution; S3, preparing a solid culture medium and fermentation; preparing a solid culture medium from a basal feed and water at a certain proportion, sterilizing, and then placing it in a sterilized conical flask; adding the bacterial solution prepared in step S2 to the solid culture medium, and inoculating the bacterial solution at a proportion of 5-10% of the total mass of the solid culture medium; sealing with a breathable film, and then placing it in a 37 ℃ constant-temperature incubator for static fermentation; obtaining the fermented feed; S4, drying and crushing; drying the fermented feed obtained in step S3 to control the moisture content to 10-15%, crushing, and then passing through a 50-100 mesh sieve to obtain the brown alginate-degrading bacterium fermented feed. In step S1, the mass ratio of sodium alginate, proteose peptone, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, magnesium sulfate, calcium chloride, sodium chloride and water is 0.6-1.2:0.3-0.9:0.05:0.05:0.02-0.05:0.01-0.02:2.5-3:

100. Bacillus weihaiensis In step S2, the culture conditions are as follows: 150-200 r / min, and culturing for 24-48 h. In step S3, the basal feed comprises 32 g of kelp powder, 20 g of horsetail powder, 20 g of sea green powder, 6 g of corn powder, 5 g of broken yeast powder, 4 g of fermented soybean meal, 4 g of shrimp powder, 4 g of vitamin premix, 3 g of fish meal, and 2 g of scallop edge powder per 100 g. In step S3, in the solid culture medium, the mass-to-volume ratio of the basal feed to water is 1:

2.

2. The method for preparing a sea cucumber-like alginate-degrading fermented feed as described in claim 1, characterized in that, In step S3, the fermentation conditions are as follows: fermentation at 37 ℃ for 5-9 days, and turning the fermented feed 2-4 times per day to disperse the fermented feed; the fermentation endpoint is determined when the content of brown alginate in the fermented feed reaches 40-50 mg / g of dry feed.

3. The method for preparing a sea cucumber-like alginate-degrading fermented feed as described in claim 1, characterized in that, In step S2, the alginate-degrading bacteria are In step S4, the drying is vacuum freeze-drying, and the drying program is as follows: -50 ℃, 5 h; -40 ℃, 5 h; -30 ℃, 5 h; -20 ℃, 5 h; -15 ℃, 5 h; -10 ℃, 4 h; -5 ℃, 4 h; 0 ℃, 3 h; 5 ℃, 3 h; 10 ℃, 1 h; 15 ℃, 2 h; 20 ℃, 2 h; 25 ℃, 1 h; and a total of 45 h. ; purchased from China Marine Microbial and Algal Culture Collection Center (MCCC); strain preservation number is 1A21688.

4. The method of claim 1, wherein the fermentation feed of the sea cucumber-like sea tangle-degrading bacteria is prepared by the steps of: 5 mixing the sea cucumber-like sea tangle-degrading bacteria with a fermentation medium; 10 inoculating the mixture with a fermentation starter; and 15 fermenting the mixture at a temperature of 25 to 35°C for 1 to 5 days. 9.Use of the fermented feed prepared by the method of any one of claims 1-8 in the feeding of Apostichopus japonicus.

5. The method for preparing a sea cucumber-like alginate-degrading fermented feed as described in claim 1, characterized in that, ​ 6. The method of claim 1, wherein the fermentation feed of the sea cucumber-associated alginate-degrading bacterium is prepared by the steps of: (a) culturing the sea cucumber-associated alginate-degrading bacterium in a culture medium; (b) collecting the fermentation broth; (c) adding a carrier to the fermentation broth; and (d) drying the fermentation broth. ​ 7. The method of claim 1, wherein the fermentation feed of the sea cucumber-associated alginate-degrading bacterium is prepared by the steps of: (a) culturing the sea cucumber-associated alginate-degrading bacterium in a culture medium; (b) collecting the fermentation broth; (c) adding a carrier to the fermentation broth; and (d) drying the fermentation broth. ​ 8. The method of claim 1, wherein the fermentation feed of the sea cucumber-associated alginate-degrading bacterium is prepared by the steps of: (a) culturing the sea cucumber-associated alginate-degrading bacterium in a culture medium; (b) collecting the fermentation broth; (c) adding a carrier to the fermentation broth; and (d) drying the fermentation broth. ​ ​ 10. Use according to claim 9, wherein The feeding conditions are as follows: the seawater temperature is 15-18 ℃, the dissolved oxygen is not less than 5 mg / L by using an air pump to supply oxygen, the seawater is replaced every week, the brown alginic acid degrading bacteria fermented feed dry powder needs to be soaked in seawater for 8-12 hours before being fed in batches, and the feed is fed once in the morning and once in the evening; the brown alginic acid degrading bacteria fermented feed feeding amount is 1%~3% of the total body weight of the sea cucumber per day in the first two weeks, and then increased to 5%; the culture time is 60 days.

Images