Aquaculture feed as well as preparation method and application thereof

Abstract

The invention relates to the technical field of aquaculture and discloses aquaculture feed as well as a preparation method and application thereof. The aquaculture feed contains schizochytrium limacinum oil, vegetable oil and Tween. The invention also discloses a preparation method of the aquaculture feed. The preparation method comprises the following steps: mixing the schizochytrium oil, the vegetable oil and the Tween, and then carrying out nano-emulsification. The invention also discloses the aquaculture feed and application of the aquaculture feed prepared by the preparation method in aquatic animal breeding. The aquaculture feed can improve the shelling efficiency and success rate in the crab breeding process, and the shelling time is short.

Description

Technical Field

[0001] The present invention relates to the technical field of aquaculture, and particularly relates to an aquaculture feed, a preparation method thereof, and an application thereof. Background Art

[0002] Imbalanced ratios of key elements such as calcium, phosphorus, and vitamins in conventional feeds for crab farming can lead to hindered hardening of the new shell. Insufficient feeding during the overwintering period results in a lack of nutritional reserves and a break in the energy supply for molting. Existing calcium supplementation techniques mostly use single-ion calcium spraying, lacking a slow-release mechanism for synergistic trace elements.

[0003] During the process of crab farming, common problems such as low molting efficiency, long molting time, and poor stress resistance generally exist. These problems lead to a molting mortality rate of 15 - 30% throughout the farming process, and the significantly extended soft shell period greatly reduces the disease resistance ability, directly affecting the growth rate and farming yield of crabs.

[0004] Traditional feeds usually cannot fully meet the special requirements for the efficient growth and molting of crabs. Therefore, it is of great significance to develop a feed additive that can promote crab molting. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems of low molting efficiency and long molting time during the process of crab farming in the prior art, and to provide an aquaculture feed, a preparation method thereof, and an application thereof. The aquaculture feed can improve the molting efficiency and success rate during the process of crab farming, and has a relatively short molting time.

[0006] To achieve the above purpose, in the first aspect of the present invention, an aquaculture feed is provided, and the aquaculture feed contains Schizochytrium oil, vegetable oil, and Tween.

[0007] Preferably, the weight ratio of the Schizochytrium oil, the vegetable oil, and the Tween is 1:1 - 30:0.1 - 0.5.

[0008] More preferably, the weight ratio of the Schizochytrium oil, the vegetable oil, and the Tween is 1:4 - 10:0.2 - 0.4.

[0009] More preferably, the Schizochytrium oil contains DHA, EPA, and DPA, and the mass ratio of the DHA and the EPA is 130 - 135:1.

[0010] More preferably, the vegetable oil is rapeseed oil and / or linseed oil.

[0011] Preferably, the feed further contains an additive, and the additive contains citric acid and / or sodium carboxymethylcellulose.

[0012] Further preferably, the additive contains citric acid and sodium carboxymethyl cellulose, and the weight ratio of the Schizochytrium oil, citric acid and sodium carboxymethyl cellulose is 1:0.01-0.5:0.01-0.5.

[0013] Further preferably, the additive further contains vitamins, and the vitamins are selected from at least one of vitamin E and / or vitamin D3.

[0014] Further preferably, the vitamins are vitamin E and vitamin D3.

[0015] Further preferably, relative to 1 part by weight of the Schizochytrium oil, the vitamin E is 0.01-0.5 part by weight, and the vitamin D3 is 0.03-0.1 part by weight.

[0016] In a second aspect of the present invention, a method for preparing an aquaculture feed is provided. The Schizochytrium oil, vegetable oil and Tween are mixed and then subjected to nanoemulsification.

[0017] Preferably, the emulsion particle size prepared by the nanoemulsification is 50-200 nm, preferably 50-100 nm.

[0018] Preferably, the weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:1-30:0.1-0.5.

[0019] Further preferably, the weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:4-10:0.2-0.4.

[0020] Further preferably, the Schizochytrium oil contains DHA, EPA and DPA, and the mass ratio of DHA and EPA is 130-135:1.

[0021] Further preferably, the vegetable oil is rapeseed oil and / or linseed oil.

[0022] Preferably, the feed further contains an additive, and the additive contains citric acid and / or sodium carboxymethyl cellulose.

[0023] Further preferably, the additive contains citric acid and sodium carboxymethyl cellulose, and the weight ratio of the Schizochytrium oil, citric acid and sodium carboxymethyl cellulose is 1:0.01-0.5:0.01-0.5.

[0024] Further preferably, the additive further contains vitamins, and the vitamins are selected from at least one of vitamin E and / or vitamin D3.

[0025] Further preferably, the vitamins are vitamin E and vitamin D3.

[0026] Further preferably, relative to 1 part by weight of the Schizochytrium oil, the vitamin E is 0.01 - 0.5 part by weight, and the vitamin D3 is 0.03 - 0.1 part by weight.

[0027] The third aspect of the present invention provides the application of the aquaculture feed described in the first aspect above or the aquaculture feed prepared by the preparation method described in the second aspect above in the aquaculture of aquatic animals.

[0028] Preferably, the aquatic animal is a crab.

[0029] Further preferably, the crab is selected from at least one of Hairy Crab, Scylla serrata, Stone Crab, Mud Crab and Hairy Crab.

[0030] Preferably, the using method of the aquaculture feed is spraying and / or mixing with feed;

[0031] The dosage of spraying is 500 - 600 mL / mu;

[0032] The dosage of mixing with feed is 5 - 9 mL / kg.

[0033] By the above technical solutions, the beneficial effects of the present invention are as follows:

[0034] The aquaculture feed provided by the present invention, through the synergistic effect among Schizochytrium oil, vegetable oil and Tween, has a scientific and balanced formula design, can comprehensively make up for the nutritional needs of crabs during the breeding process, improve the molting efficiency and success rate during the crab breeding process, and the molting time is shorter. Further found that the aquaculture feed of the present invention can significantly enhance the feed intake of crabs, reduce the remaining feed, improve the feed conversion efficiency, and effectively reduce the feeding cost. Detailed Embodiments

[0035] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and a single point value, and between single point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0036] The first aspect of the present invention provides an aquaculture feed, which contains Schizochytrium oil, vegetable oil and Tween. During the research on aquaculture feed, the inventors of the present invention unexpectedly found that through the synergistic effect among Schizochytrium oil, vegetable oil and Tween, the formula design is scientific and balanced, which can comprehensively make up for the nutritional needs of crabs during the breeding process, improve the molting efficiency and success rate during the crab breeding process, and the molting time is shorter. Further findings show that the aquaculture feed of the present invention can significantly enhance the feed intake of crabs, reduce the remaining feed, improve the feed conversion efficiency, and effectively reduce the feeding cost.

[0037] In the present invention, the preparation process of Schizochytrium oil includes: fermentation, enzymatic hydrolysis, cell wall disruption, solvent extraction, centrifugation, and purification. The present invention has no strict limitation on the fermentation process of Schizochytrium oil, and conventional fermentation processes in the art can be used for fermentation production. Exemplarily, Schizochytrium oil is obtained by fermenting and culturing Schizochytrium sp. HX308, which is provided by the laboratory of Professor Huang He of Nanjing Normal University and is currently deposited in the China Center for Type Culture Collection (CCTCC), with the deposit number CCTCC No. M209059, and has been disclosed in CN104974944A. The fermentation conditions include carbon source, nitrogen source, and trace elements, maintaining appropriate temperature (28 - 32°C), pH (6.5 - 7.5), and dissolved oxygen level to promote the accumulation of lipid metabolites. Carbon source: Glucose or sucrose can be used, and the concentration is set at 10 - 20 g / L; Nitrogen source: Such as nitrate, urea, or ammonium salt, and the concentration is set at 1 - 2 g / L Trace elements: Added according to the conventional formula of aquatic microalgae culture medium (such as MgSO4, K2HPO4, FeSO4, MnSO4, ZnSO4, etc.) to ensure sufficient trace elements. The activated Schizochytrium strain is inoculated into the above medium; the temperature is controlled between 28 - 32°C, and the pH is adjusted to 6.5 - 7.5; the stirring rate or ventilation volume is adjusted to ensure sufficient dissolved oxygen (such as stirring at 200 rpm or using a ventilation device to maintain a good dissolved oxygen level); the fermentation time is generally controlled within 120 - 140 hours, during which the growth of the bacteria and the accumulation of oil are monitored. When the cell density and lipid metabolites reach the expected peak values, the fermentation can be stopped. After the fermentation is completed, the fermentation broth is harvested, an appropriate amount of cell wall hydrolase (such as cellulase, chitosanase) is added, and it is treated at a temperature of 45 - 55°C for 2 - 4 hours to effectively disrupt the cell wall and release the lipid substances inside the Schizochytrium cells. Ethanol, isopropanol, or n-hexane is used as the extraction solvent, and the solvent is added in a ratio of 1:3 - 5 based on the wet weight of the bacteria. The mixture is stirred and extracted at a temperature of 40 - 50°C for 3 - 5 hours to dissolve the oil components in the bacteria. After the extraction is completed, the mixture is placed in a centrifuge (such as 4000 rpm, 10 - 15 minutes) to separate the solid and liquid, and the supernatant is collected. This supernatant contains the dissolved oil. The extract is subjected to rotary evaporation or vacuum distillation to recover the solvent. After the evaporation is completed, the residue obtained is Schizochytrium oil; the oil is filtered (such as using a microporous filter) to remove impurities and cooled at room temperature to obtain Schizochytrium oil.

[0038] According to the present invention, the Tween is Tween 20 and / or Tween 40. The inventors found that when the above preferred implementation mode is adopted, the stability of the components in the feed can be improved, the nutritional requirements of crabs during the breeding process can be comprehensively supplemented, the molting efficiency and success rate during the crab breeding process can be improved, and the molting time can be shortened.

[0039] According to the present invention, preferably, the weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:1-30:0.1-0.5, specifically it can be 1:1:0.1, 1:15:0.3, 1:30:0.5, or any value between the above two ratios. Further preferably, the weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:4-10:0.2-0.4, specifically it can be 1:4:0.2, 1:8:0.3, 1:10:0.4, or any value between the above two ratios. The inventors found that when the above preferred embodiments are adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0040] According to the present invention, further preferably, the Schizochytrium oil contains DHA, EPA and DPA, and the mass ratio of DHA and EPA is 130-135:1, specifically it can be 130:1, 131:1, 132:1, 133:1, 134:1, 135:1, or any value between the above two values. The inventors found that when the above preferred embodiments are adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, further improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0041] According to the present invention, further preferably, the vegetable oil is rapeseed oil and / or linseed oil. Specifically, it can be rapeseed oil alone, or linseed oil alone, or a mixture of rapeseed oil and linseed oil. The inventors found that when the above preferred embodiments are adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, further improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0042] According to the present invention, preferably, the feed further contains an additive, and the additive contains citric acid and / or sodium carboxymethylcellulose. Further preferably, the additive contains citric acid and sodium carboxymethylcellulose, and the weight ratio of the Schizochytrium oil, citric acid and sodium carboxymethylcellulose is 1:0.01-0.5:0.01-0.5, specifically it can be 1:0.01:0.01, 1:0.3:0.3, 1:0.5:0.5, or any value between the above two ratios. The inventors found that when the above preferred embodiments are adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, further improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0043] According to the present invention, further preferably, the additive further contains vitamins, and the vitamins are selected from at least one of vitamin E and / or vitamin D3. More preferably, the vitamins are vitamin E and vitamin D3. The inventors have found that when the above preferred embodiments are adopted, the nutritional requirements of crabs during the breeding process can be comprehensively supplemented, the molting efficiency and success rate during the crab breeding process can be further improved, and the molting time can be shortened.

[0044] According to the present invention, further preferably, relative to 1 part by weight of the Schizochytrium oil, the vitamin E is 0.01 - 0.5 part by weight, and the vitamin D3 is 0.03 - 0.1 part by weight. The inventors have found that when the above preferred embodiments are adopted, the nutritional requirements of crabs during the breeding process can be comprehensively supplemented, the molting efficiency and success rate during the crab breeding process can be further improved, and the molting time can be shortened.

[0045] The second aspect of the present invention provides a method for preparing an aquaculture feed, which comprises mixing Schizochytrium oil, vegetable oil and Tween and then performing nanoemulsification. The inventors have found that the aquaculture feed prepared by the above method, through the synergistic effect among Schizochytrium oil, vegetable oil and Tween, has a scientific and balanced formula design, can comprehensively supplement the nutritional requirements of crabs during the breeding process, improve the molting efficiency and success rate during the crab breeding process, and has a short molting time. It is further found that the aquaculture feed of the present invention can significantly enhance the feed intake of crabs, reduce the remaining feed, improve the feed conversion efficiency, and effectively reduce the feeding cost.

[0046] The present invention has no strict limitation on the specific method of nanoemulsification, and conventional preparation methods in the art can be adopted, such as high-pressure homogenization method and ultrasonic emulsification method. Preferably, the emulsion particle size prepared by the nanoemulsification is 50 - 200 nm, specifically it can be 50 nm, 100 nm, 150 nm, 200 nm, or any value between the above two values; preferably 50 - 100 nm, specifically it can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or any value between the above two values. The inventors have found that when the above preferred embodiments are adopted, the stability of each component in the feed can be enhanced, the absorption rate can be improved, the molting efficiency and success rate during the crab breeding process can be further improved, and the molting time can be shortened.

[0047] According to the present invention, preferably, the weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:1 - 30:0.1 - 0.5, specifically it can be 1:1:0.1, 1:15:0.3, 1:30:0.5, or any value between the above two values; further preferably, the weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:4 - 10:0.2 - 0.4, specifically it can be 1:4:0.2, 1:8:0.3, 1:10:0.4, or any value between the above two ratios. The inventors found that when the above preferred implementation mode is adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, further improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0048] According to the present invention, further preferably, the Schizochytrium oil contains DHA, EPA and DPA.

[0049] And the mass ratio of the DHA and EPA is 130 - 135:1, specifically it can be 130:1, 131:1, 132:1, 133:1, 134:1, 135:1, or any value between the above two values. The inventors found that when the above preferred implementation mode is adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, further improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0050] According to the present invention, further preferably, the vegetable oil is rapeseed oil and / or linseed oil. Specifically, it can be rapeseed oil alone, or linseed oil alone, or a mixture of rapeseed oil and linseed oil. The inventors found that when the above preferred implementation mode is adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, further improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0051] According to the present invention, preferably, the feed further contains an additive, and the additive contains citric acid and / or sodium carboxymethylcellulose. Further preferably, the additive contains citric acid and sodium carboxymethylcellulose, and the weight ratio of the Schizochytrium oil, citric acid and sodium carboxymethylcellulose is 1:0.01 - 0.5:0.01 - 0.5, specifically it can be 1:0.01:0.01, 1:0.3:0.3, 1:0.5:0.5, or any value between the above two ratios. The inventors found that when the above preferred implementation mode is adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, further improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0052] According to the present invention, further preferably, the additive further contains vitamins, and the vitamins are selected from at least one of vitamin E and / or vitamin D3. More preferably, the vitamins are vitamin E and vitamin D3. The inventors have found that when the above preferred embodiments are adopted, the nutritional requirements of crabs during the breeding process can be comprehensively supplemented, the molting efficiency and success rate during the crab breeding process can be further improved, and the molting time can be shortened.

[0053] According to the present invention, further preferably, relative to 1 part by weight of the Schizochytrium oil, the vitamin E is 0.01 - 0.5 part by weight, and the vitamin D3 is 0.03 - 0.1 part by weight. The inventors have found that when the above preferred embodiments are adopted, the nutritional requirements of crabs during the breeding process can be comprehensively supplemented, the molting efficiency and success rate during the crab breeding process can be further improved, and the molting time can be shortened.

[0054] According to the present invention, the preparation method further includes adding a solvent, preferably water, and relative to 1 part by weight of the Schizochytrium oil, the water is 1750 - 2000 parts by weight. The inventors have found that adding water can improve the stability of the emulsified feed.

[0055] As a relatively preferred embodiment of the present invention, the preparation method of the aquaculture feed is as follows: Schizochytrium oil, rapeseed oil, Tween, vitamin E, vitamin D3, citric acid, sodium carboxymethylcellulose and water are mixed and then subjected to nano - emulsification to prepare an aquaculture feed with an emulsion particle size of 50 - 200 nm; wherein the Schizochytrium oil contains DHA, EPA and DPA, and the mass ratio of DHA to EPA is 130 - 135:1; relative to 1 part by weight of the Schizochytrium oil, the rapeseed oil is 4 - 10 parts by weight, the Tween is 0.2 - 0.4 part by weight, the vitamin E is 0.01 - 0.5 part by weight, the vitamin D3 is 0.03 - 0.1 part by weight, the citric acid is 0.01 - 0.5 part by weight, the sodium carboxymethylcellulose is 0.01 - 0.5 part by weight, and the water is 1750 - 2000 parts by weight.

[0056] The third aspect of the present invention provides the application of the aquaculture feed described in the first aspect above or the aquaculture feed prepared by the preparation method described in the second aspect above in aquaculture. Preferably, the aquatic animal is a crab. Further preferably, the crab is selected from at least one of Hairy Crab, Scylla serrata, Lithodes aequispinus, Grapsus tenuicrustatus and Eriocheir sinensis. The inventors have found that when the above aquaculture feed is used to feed crabs, the nutritional requirements of crabs during the breeding process can be comprehensively supplemented, the molting efficiency and success rate during the crab breeding process can be further improved, and the molting time can be shortened.

[0057] According to the present invention, preferably, the aquaculture feed is used by spraying and / or mixing with feed; specifically, it can adopt a single spraying method, or a single mixing method, or a combination of spraying and mixing. The dosage for spraying is 500 - 600 mL / mu, specifically it can be 500 mL / mu, 520 mL / mu, 540 mL / mu, 560 mL / mu, 580 mL / mu, 600 mL / mu, or any value between the above two values; the dosage for mixing is 5 - 9 mL / kg, specifically it can be 5 mL / kg, 6 mL / kg, 7 mL / kg, 8 mL / kg, 9 mL / kg, or any value between the above two values. The inventors found that when the above preferred implementation mode is adopted, it can comprehensively make up for the nutritional needs of crabs during the breeding process, further improve the molting efficiency and success rate during the crab breeding process, and shorten the molting time.

[0058] The present invention will be described in detail below through examples.

[0059] In the following examples, the Schizochytrium oil is obtained by fermentation and culture of Schizochytrium sp. HX308; other materials and reagents used, unless otherwise specified, can be obtained from commercial channels. The experimental methods without specific conditions noted in the examples are usually carried out under conventional conditions, or according to the conditions recommended by the manufacturer.

[0060] Example 1

[0061] Schizochytrium oil, rapeseed oil, Tween 20, vitamin E, vitamin D3, citric acid, sodium carboxymethylcellulose and water are mixed and then subjected to nanoemulsification to prepare an aquaculture feed 1 with an emulsion particle size of 50 nm; the Schizochytrium oil contains DHA, EPA and DPA, and the mass ratio of DHA to EPA is 130:1; relative to 1 part by weight of Schizochytrium oil, rapeseed oil is 4 parts by weight, Tween is 0.2 part by weight, vitamin E is 0.01 part by weight, vitamin D3 is 0.03 part by weight, citric acid is 0.01 part by weight, sodium carboxymethylcellulose is 0.01 part by weight, and water is 1750 parts by weight.

[0062] Example 2

[0063] Schizochytrium oil, rapeseed oil, Tween 20, vitamin E, vitamin D3, citric acid, sodium carboxymethylcellulose and water were mixed and then subjected to nanoemulsification to prepare an aquaculture feed 2 with an emulsion particle size of 100 nm; wherein the Schizochytrium oil contains DHA, EPA and DPA, and the mass ratio of DHA to EPA is 132:1; relative to 1 part by weight of Schizochytrium oil, rapeseed oil is 8 parts by weight, Tween is 0.3 parts by weight, vitamin E is 0.2 parts by weight, vitamin D3 is 0.08 parts by weight, citric acid is 0.3 parts by weight, sodium carboxymethylcellulose is 0.2 parts by weight, and water is 1850 parts by weight.

[0064] Example 3

[0065] Schizochytrium oil, rapeseed oil, Tween 20, vitamin E, vitamin D3, citric acid, sodium carboxymethylcellulose and water were mixed and then subjected to nanoemulsification to prepare an aquaculture feed 3 with an emulsion particle size of 200 nm; wherein the Schizochytrium oil contains DHA, EPA and DPA, and the mass ratio of DHA to EPA is 135:1; relative to 1 part by weight of Schizochytrium oil, rapeseed oil is 10 parts by weight, Tween is 0.4 parts by weight, vitamin E is 0.5 parts by weight, vitamin D3 is 0.1 parts by weight, citric acid is 0.5 parts by weight, sodium carboxymethylcellulose is 0.5 parts by weight, and water is 2000 parts by weight.

[0066] Example 4

[0067] The aquaculture feed was prepared according to the method of Example 1, except that rapeseed oil was replaced with linseed oil.

[0068] Example 5

[0069] The aquaculture feed was prepared according to the method of Example 1, except that the amount of rapeseed oil was changed from 4 parts by weight to 30 parts by weight.

[0070] Example 6

[0071] The aquaculture feed was prepared according to the method of Example 1, except that the amount of rapeseed oil was changed from 4 parts by weight to 1 part by weight.

[0072] Example 7

[0073] The aquaculture feed was prepared according to the method of Example 1, except that the amount of Tween 20 was changed from 0.2 parts by weight to 0.1 parts by weight.

[0074] Example 8

[0075] The aquaculture feed was prepared according to the method of Example 1, except that the amount of Tween 20 was changed from 0.2 parts by weight to 0.5 parts by weight.

[0076] Example 9

[0077] The aquaculture feed was prepared according to the method of Example 1, except that citric acid was not added.

[0078] Example 10

[0079] The aquaculture feed was prepared according to the method of Example 1, except that 4 parts by weight of rapeseed oil was replaced with 60 parts by weight of rapeseed oil.

[0080] Example 11

[0081] The aquaculture feed was prepared according to the method of Example 1, except that 0.2 part by weight of Tween 20 was replaced with 1 part by weight of Tween 20.

[0082] Comparative Example 1

[0083] The aquaculture feed was prepared according to the method of Example 1, except that rapeseed oil was not added.

[0084] Comparative Example 2

[0085] The aquaculture feed was prepared according to the method of Example 1, except that Schizochytrium sp. oil was replaced with Schizochytrium sp. powder. The Schizochytrium sp. powder was purchased from Zihuo Biotechnology (Changzhou) Co., Ltd.

[0086] Comparative Example 3

[0087] The aquaculture feed was prepared according to the method of Example 1, except that Tween 20 was replaced with Span 20.

[0088] Test Example

[0089] Experimental grouping: A number of healthy crabs with similar specifications were randomly divided into sixteen groups, with 30 crabs in each group to ensure the statistical significance of the experimental results. Fifteen of the groups were experimental groups, and the last group was the control group. The experimental groups were fed the test feeds prepared in the examples and comparative examples, and the control group was fed a common feed (as a control benchmark). The composition of the common feed was 27 kg of fish meal, 22 kg of soybean meal, 12 kg of protein powder, 29 kg of corn flour, and 10 kg of wheat bran. Among them, the fish meal was purchased from Mufengyuan Feed Co., Ltd., the soybean meal was purchased from Lvshui Chemical Co., Ltd., the protein powder was purchased from Shuangshi Environmental Technology Co., Ltd., the corn flour was purchased from Tengxiang Chemical Co., Ltd., and the wheat bran was purchased from Qingshan Chemical Technology Co., Ltd. The prepared feed additive was added to the daily feed at a ratio of 0.5% of the crab body weight, and after being stirred evenly, it was fed.

[0090] Cultivation environment: The sixteen groups of crabs were all placed in the same and suitable cultivation environment to ensure that the water quality (parameters such as temperature, pH value, dissolved oxygen content, etc. were stable and met the growth requirements of crabs), the light duration and intensity were consistent, and the size and structure of the cultivation ponds were also the same to exclude the interference of environmental factors on the molting of crabs.

[0091] Cultivation cycle and observation frequency: The duration of the experiment was set as a complete molting cycle of crabs, starting from the end of the fourth molt to about one week after the end of the fifth molt. Observe and record the status of crabs regularly every day, with a focus on whether there are signs of molting and the completion of molting. During the expected period of concentrated molting, increase the observation frequency to once every 4 hours to ensure accurate recording of the molting time.

[0092] Recording of molting status: Record in detail the molting time of each crab and whether the molting process is smooth (such as abnormal situations like difficulty in shell peeling and body damage). For the crabs after molting, measure and record their weight, carapace width, length and other specification data in a timely manner for subsequent analysis. The test results are shown in Table 1.

[0093] Table 1

[0094]

[0095] It can be seen from the results in Table 1 that the embodiments of the present invention have significantly better effects.

[0096] Application Example 1

[0097] Application of the mixing and feeding method

[0098] Add the aquaculture feed prepared in Example 1 to the daily feed at a ratio of 0.5% of the crab weight, stir evenly and then feed. Set up a control group and a feeding group for the feeding experiment under the same pond conditions. The experimental period is 60 days, and the daily sampling quantity is 100. The test data are shown in Table 2.

[0099] Table 2

[0100] Experimental group Control group Stocking density 2,000 per mu 2,000 per mu Average size at the fourth shell Male: 2.3 taels, Female: 2.5 taels Male: 2.0 taels, Female: 1.8 taels Average size at the fifth shell Male: 4.7 taels, Female: 3.5 taels Male: 4.2 taels, Female: 3.0 taels Increase in shell width from the fourth to the fifth shell Male: 1.1 cm, Female: 0.9 cm Male: 0.8 cm, Female: 0.7 cm Soft shell ratio 2％ 8％ Molting cycle 30.7 days 42.5 days

[0101] Application Example 2

[0102] Application of the spraying and feeding method

[0103] Dilute the aquaculture feed prepared in Example 1 by 1000 times and spray it at a ratio of 3 liters per mu of water body. The stocking density is 2000 per mu. The experimental period is 10 days, and the daily sampling quantity is 100. The test data are shown in Table 3.

[0104] Table 3

[0105] Experimental group Control group Daily death toll (the next day) 25 90 Daily death toll (the fourth day) 6 26 Molting integrity rate (success rate) 96％ 86％ Soft shell crab ratio (the fifth day) 2％ 6％ Average molting time 55-60s 80-90s

[0106] Control group

[0107] The commercially available ionic calcium additive was added to the daily feed at a ratio of 0.5% of the crab body weight, stirred evenly and then fed. The ionic calcium additive was purchased from Nanjing Wodun Biotechnology Co., Ltd.

[0108] The stocking density was 2,000 crabs per mu, the experimental period was 7 days, and the daily sampling quantity was 100 crabs. The test results are shown in Table 4.

[0109] Table 4

[0110] Experimental group Control group Daily death toll (the next day) 28 76 Daily death toll (the fourth day) 6 18 Average size at the fifth shell Male: 4.5 taels, Female: 3.5 taels Male: 4.1 taels, Female: 3.2 taels Soft shell crab ratio 1％ 4％ Rate of "red mouth and yellow liver" 85％ 67％

[0111] The aquaculture feed provided by the present invention, through the synergistic effect among Schizochytrium oil, vegetable oil and Tween, has a scientific and balanced formula design, can comprehensively make up for the nutritional needs of crabs during the breeding process, improve the molting efficiency and success rate during the crab breeding process, and the molting time is shorter. It is further found that the aquaculture feed of the present invention can significantly enhance the feed intake of crabs, reduce the remaining feed, improve the feed conversion efficiency, and effectively reduce the breeding cost.

[0112] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. An aquaculture feed, characterized in that, The aquaculture feed contains Schizochytrium oil, vegetable oil and Tween.

2. The aquaculture feed according to claim 1, wherein The weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:1 - 30:0.1 - 0.5; Preferably, the weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:4 - 10:0.2 - 0.4; Preferably, the Schizochytrium oil contains DHA, EPA and DPA, and the mass ratio of DHA and EPA is 130 - 135:1; Preferably, the vegetable oil is rapeseed oil and / or linseed oil.

3. The aquaculture feed according to claim 2, characterized in that, The feed also contains an additive, and the additive contains citric acid and / or sodium carboxymethylcellulose; Preferably, the additive contains citric acid and sodium carboxymethylcellulose, and the weight ratio of the Schizochytrium oil, citric acid and sodium carboxymethylcellulose is 1:0.01 - 0.5:0.01 - 0.5; Preferably, the additive also contains vitamins, and the vitamins are selected from at least one of vitamin E and / or vitamin D3; Preferably, the vitamins are vitamin E and vitamin D3; Preferably, relative to 1 part by weight of the Schizochytrium oil, the vitamin E is 0.01 - 0.5 part by weight, and the vitamin D3 is 0.03 - 0.1 part by weight.

4. A preparation method of an aquaculture feed, characterized in that Wherein, The Schizochytrium oil, vegetable oil and Tween are mixed and then subjected to nanoemulsification.

5. The preparation method according to claim 4, characterized in that, The emulsion particle size prepared by the nanoemulsification is 50 - 200 nm, preferably 50 - 100 nm.

6. The preparation method according to claim 4, characterized in that, The weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:1 - 30:0.1 - 0.5; Preferably, the weight ratio of the Schizochytrium oil, vegetable oil and Tween is 1:4 - 10:0.2 - 0.4; Preferably, the Schizochytrium oil contains DHA, EPA and DPA, and the mass ratio of DHA and EPA is 130 - 135:1; Preferably, the vegetable oil is rapeseed oil and / or linseed oil.

7. The preparation method according to claim 6, characterized in that, The feed also contains an additive, and the additive contains citric acid and / or sodium carboxymethylcellulose; Preferably, the additive contains citric acid and sodium carboxymethylcellulose, and the weight ratio of the Schizochytrium oil, citric acid and sodium carboxymethylcellulose is 1:0.01 - 0.5:0.01 - 0.5; Preferably, the additive also contains vitamins, and the vitamins are selected from at least one of vitamin E and / or vitamin D3; Preferably, the vitamins are vitamin E and vitamin D3; Preferably, relative to 1 part by weight of the Schizochytrium oil, the vitamin E is 0.01 - 0.5 part by weight, and the vitamin D3 is 0.03 - 0.1 part by weight.

8. Application of the aquaculture feed according to any one of claims 1 - 3 or the aquaculture feed prepared by the preparation method according to any one of claims 4 - 7 in aquaculture of aquatic animals.

9. The application according to claim 8, wherein The aquatic animal is a crab; Preferably, the crab is selected from at least one of Chinese mitten crab, green crab, stone crab, water crab and hairy crab.

10. The application according to claim 8 or 9, characterized in that, The using method of the aquaculture feed is spraying and / or mixing with feed; The dosage of spraying is 500 - 600 mL / mu; The dosage of mixing with feed is 5 - 9 mL / kg.

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