Plant source composition for preventing and treating aquatic products as well as preparation method and application of plant source composition

Abstract

The invention belongs to the technical field of aquaculture, and particularly relates to a botanical composition for preventing and treating aquatic products as well as a preparation method and application of the botanical composition. The plant source composition is prepared from the following raw materials in parts by mass: 0.1 to 0.5 part of peppermint oil, 0.5 to 1 part of eucalyptus oil, 0.2 to 0.6 part of chili oil, 0.3 to 0.6 part of thymol, 0.1 to 0.3 part of cinnamyl aldehyde, 0.5 to 1 part of antifebrile dichroa oil, 8 to 18 parts of an emulsifier, 4 to 14 parts of a cosolvent and 65 to 85 parts of water. The plant-derived composition disclosed by the invention not only has relatively good safety and bioavailability, but also has relatively strong anti-parasitic activity and broad-spectrum bactericidal effect, and can effectively prevent and control enteritis, white stool and other problems caused by infection of parasites, vibrios and fungi of aquaculture animals.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and specifically relates to a plant-derived composition for preventing and treating aquatic products, and a preparation method and application thereof. Background Art

[0002] In the process of aquaculture, parasites, especially sporozoans, have brought great challenges to the aquaculture industry. Common aquaculture sporozoans include iodine bubble worms, sticky worms, and monopolar worms. Different types of sporozoans differ in morphology, parasitic sites, and pathogenicity. For example, iodine bubble worms mostly parasitize on the gills, body surface, and internal organs of fish; sticky worms mainly parasitize on the gills, intestines, and other parts of fish; monopolar worms often parasitize in the muscle tissue of fish. Sporozoans have a complex life history, which generally includes stages such as spore formation, release, infection of the host, and development in the host. The spores of sporozoans have strong resistance to adversity and can survive for a long time under harsh environmental conditions. For example, the sporozoan EHP has a double-layer chitin spore wall and is highly resistant to stress. It is difficult for conventional drugs to penetrate the spore wall to kill the spores. Moreover, the sporozoan EHP is an intracellular parasite, and almost no drug can penetrate the cell membrane to kill the sporozoan. It has a double-layer protective wall, can hibernate in certain environments, and has the ability to spread and spread for a long time.

[0003] Patent CN 115845015 A discloses a plant-based composite preparation for aquaculture anthelmintics / insect inhibition and its preparation method, the composite preparation includes a composite plant extract, green peel orange oil, a thickener, and an emulsifier stabilizer, and the composite plant extract is a mixed extract of eucalyptus leaves, ginger, perilla, lemongrass, cardamine, Melaleuca alternifolia branches and leaves, and magnolia. The composite preparation of the invention can effectively inhibit the proliferation of ciliates, ringworms, sporozoans, wheelworms, Ichthyophthirius, anchorhead worms, etc. in the aquaculture water environment, repel their attachment to the body of aquatic animals, quickly repair the attachment tissue of the insect body, and protect aquatic animals from parasites. However, the product of the patent is used to dispel parasites and prevent parasites from attaching to the surface of aquatic products, but it does not mention whether it has an inhibitory effect on parasites in the body, and the drugs currently on the market cannot simultaneously and efficiently inhibit pathogens and parasites in aquatic products.

[0004] Therefore, it is of great significance to develop a product with plant extracts as the main raw material to prevent parasites in aquatic products and improve the quality of aquatic products. Summary of the invention

[0005] The invention discloses a plant-based composition for preventing and controlling aquatic products, and a preparation method and application thereof. Peppermint oil, eucalyptus oil, chili oil, thymol, cinnamaldehyde and radix schizonepetae oil are used as main active ingredients, and an emulsifier, a cosolvent and a sustained-release carrier are compounded. The prepared plant-based composition has good safety and bioavailability, strong antiparasitic activity and a broad-spectrum bactericidal effect, and can effectively prevent and control problems such as enteritis and white stools caused by parasites, vibrio and fungal infections in aquatic animals.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a plant-derived composition for controlling aquatic products, which comprises the following raw materials in parts by weight:

[0008] 0.1-0.5 parts of peppermint oil, 0.5-1 parts of eucalyptus oil, 0.2-0.6 parts of chili oil, 0.3-0.6 parts of thymol, 0.1-0.3 parts of cinnamaldehyde, 0.5-1 parts of changshan oil, 8-18 parts of emulsifier, 4-14 parts of cosolvent, and 65-85 parts of water.

[0009] In some embodiments, the raw material further includes 0.6-2 parts by mass of a sustained-release carrier.

[0010] In some embodiments, the preparation steps of the sustained-release carrier are:

[0011] (1) placing chitosan monomer in deionized water and adjusting the pH thereof to 4-5 to obtain solution 1;

[0012] (2) placing oligomeric hyaluronic acid in deionized water, and adding an activator thereto to obtain solution 2;

[0013] (3) Add solution 2 to solution 1 under stirring at 20-30° C., stir and react for 10-16 h, then add hydroxypropyl-β-cyclodextrin, stir and react at 20-30° C. for 6-10 h, dialyze, and freeze-dry to obtain a sustained-release carrier.

[0014] In some embodiments, the chitosan monomer is N-acetyl-D-glucosamine or D-glucosamine.

[0015] In some embodiments, the molar ratio of the chitosan monomer to the oligomeric hyaluronic acid is (25-28):1.

[0016] Preferably, the molar ratio of the chitosan monomer to the oligomeric hyaluronic acid is 26.5:1.

[0017] In some embodiments, the ratio of the mass of the hydroxypropyl-β-cyclodextrin to the total mass of the chitosan monomer and the oligomeric hyaluronic acid is (0.6-0.9):1.

[0018] Preferably, the ratio of the mass of the hydroxypropyl-β-cyclodextrin to the total mass of the chitosan monomer and the oligomeric hyaluronic acid is 0.75:1.

[0019] In some embodiments, the emulsifier includes soy lecithin, sucrose fatty acid esters, and Span 80.

[0020] In some embodiments, the HLB value of the emulsifier is 8-13.

[0021] Preferably, the mass ratio of the soybean lecithin, sucrose fatty acid ester and Span 80 is (1-2):(6-9):(0.5-2).

[0022] The second aspect of the present invention provides a method for preparing the plant-derived composition of the above scheme, comprising the following preparation steps:

[0023] At 20-30°C, peppermint oil, eucalyptus oil, chili oil, thymol, cinnamaldehyde and shanshan oil are mixed and stirred for 15-30 minutes to obtain a mixture, and then a sustained-release carrier is added to the mixture twice, and each time the sustained-release carrier is added, the mixture is stirred for 20-30 minutes. Finally, an emulsifier, a cosolvent and water are added, and the mixture is stirred evenly to obtain a plant-derived composition.

[0024] The third aspect of the present invention provides an application of the plant-derived composition described in the above scheme in the field of preventing and controlling aquatic product parasites, and the plant-derived composition has a parasite inhibition rate of >80% on aquatic animals.

[0025] The present invention uses peppermint oil, eucalyptus oil, chili oil, thymol, cinnamaldehyde and shanshan oil as main active ingredients, and compound emulsifiers, cosolvents and sustained-release carriers. The prepared plant-based composition not only has good safety and bioavailability, but also has strong antiparasitic activity and broad-spectrum bactericidal effect, and can effectively prevent and control enteritis, white stools and other problems caused by parasites, Vibrio and fungal infections in aquatic animals.

[0026] The applicant has found that the combination of plant essential oils such as peppermint oil, eucalyptus oil, chili oil, thymol, cinnamaldehyde and changshan oil in the present invention can play a synergistic role and enhance the inhibitory effect on parasites in aquatic products. The mechanism of action of the plant-derived composition of the present invention may be to destroy the viability of these parasites by acting on the DNA topoisomerase II of pathogenic parasites and sporozoans. These compounds interact with DNA bases, occupy active sites, and prevent the normal function of topoisomerase II, thereby causing the death of parasites. At the same time, plant essential oils can also regulate the immune system of aquatic products and enhance their resistance to parasites.

[0027] In addition, in order to improve the stability of the composition and control the release rate of the active ingredient, the present invention, by controlling the reaction conditions (temperature, pH value, reaction time and reactant concentration), grafts N-acetyl-D-glucosamine with a specific chemical structure and biological activity onto oligomeric hyaluronic acid through chemical reaction, giving new functional characteristics of oligomeric hyaluronic acid with good biocompatibility and water solubility, and grafted oligomeric hyaluronic acid has higher stability, biological activity and targeting, which is conducive to the targeted release of active drugs. In addition, a certain amount of hydroxypropyl-β-cyclodextrin is added in the later stage, and hydroxypropyl-β-cyclodextrin may wrap chitosan monomer-oligomeric hyaluronic acid complex in its cavity through inclusion reaction, forming a stable inclusion compound, and the slow-release carrier is added to the plant essential oil composition, and the encapsulation and slow release of plant essential oil can be realized, and its stability and bioavailability are improved. The slow-release carrier can control the release rate of plant essential oil, so that it continues to play a role in aquatic products, thereby improving the inhibitory effect on parasites. At the same time, the slow-release carrier can also reduce the toxicity and side effects of plant essential oil, and improve its safety.

[0028] In addition, the applicant has also found that the emulsifier composed of soybean lecithin, sucrose fatty acid ester and Span 80 with an HLB value of 8-13 can better emulsify the plant essential oil of the present invention, so that the originally immiscible oil phase and water phase form a uniform and stable emulsion, prevent the plant essential oil from aggregating and stratifying in the mixture, and improve the stability of the composition. Moreover, the emulsifier can also evenly disperse the plant essential oil in water, increasing the contact opportunity between the plant essential oil and parasites. Since parasites usually live in or on the body of aquatic products, plant essential oils need to pass through an aqueous medium to better act on parasites. The emulsified plant essential oil has a smaller particle size and a larger specific surface area, and can be more effectively diffused to various parts of aquatic products, improving the inhibitory effect on parasites.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The plant-derived composition of the present invention not only has good safety and bioavailability, but also has strong antiparasitic activity and broad-spectrum bactericidal effect, and can effectively prevent and control problems such as enteritis and white stool caused by parasites, Vibrio, and fungal infections in aquatic animals.

[0031] 2. The slow-release carrier prepared by the present invention can achieve the encapsulation and slow release of plant essential oils, thereby improving their stability and bioavailability. The slow-release carrier can control the release rate of plant essential oils, so that they can continue to play a role in aquatic products, thereby improving the inhibitory effect on parasites. At the same time, the slow-release carrier can also reduce the toxicity and side effects of plant essential oils, thereby improving their safety.

[0032] 3. The emulsifier composed of soybean lecithin, sucrose fatty acid ester and Span 80 can better emulsify the plant essential oil in the system, so that the originally immiscible oil phase and water phase form a uniform and stable emulsion, prevent the plant essential oil from aggregating and stratifying in the mixture, and improve the stability and dispersibility of the composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 , Figure 2 All are test ponds for tilapia culture in performance testing;

[0034] Figure 3 Test pond for shrimp culture in performance testing. DETAILED DESCRIPTION

[0035] Now describe in detail various exemplary embodiments of the present invention, this detailed description should not be considered as limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing a particular embodiment, and are not used to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the range.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. Various modifications and variations may be made to the specific embodiments of the present invention specification without departing from the scope or spirit of the present invention, which will be apparent to those skilled in the art. Other embodiments obtained from the present invention specification will be apparent to the technician. The present application specification and examples are exemplary only.

[0037] The words “include,” “including,” “have,” or “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0038] The mass fractions described in the following embodiments may be grams, kilograms, tons or other mass units.

[0039] The compound monomers and related reagents used in the following examples can all be purchased from the market. Among them, the Mw of the oligomeric hyaluronic acid used in the present invention is 5000; the molecular weight cutoff of the dialysis bag used is 12000; and the cosolvent used is ethanol.

[0040] Preparation Example 1

[0041] The preparation steps of the sustained-release carrier are as follows:

[0042] (1) 0.265 mol of N-acetyl-D-glucosamine was placed in 1 L of deionized water and the pH thereof was adjusted to 4.5 to obtain solution 1;

[0043] (2) 0.01 mol of oligomeric hyaluronic acid was placed in 200 mL of deionized water, and 0.035 mol of NHS and 0.053 mol of EDC were added thereto to obtain solution 2;

[0044] (3) Solution 2 was added to solution 1 at 100 rpm and 20°C, and the mixture was stirred for 13 h. Then, 81.5 g of hydroxypropyl-β-cyclodextrin was added thereto, and the mixture was stirred for 8 h at 25°C. The mixture was dialyzed for 72 h, and freeze-dried to obtain a sustained-release carrier.

[0045] Preparation Example 2

[0046] The preparation steps of the sustained-release carrier are the same as those of Preparation Example 2, except that an equimolar amount of D-glucosamine is used instead of N-acetyl-D-glucosamine.

[0047] Preparation Example 3

[0048] The preparation steps of the sustained-release carrier are the same as those in Preparation Example 2, except that 0.02 mol of N-acetyl-D-glucosamine is used.

[0049] Preparation Example 4

[0050] The preparation steps of the sustained-release carrier are the same as those in Preparation Example 2, except that 0.005 mol of N-acetyl-D-glucosamine is used.

[0051] Preparation Example 5

[0052] 0.01 mol of oligomeric hyaluronic acid was placed in 200 mL of deionized water, and 37.5 g of hydroxypropyl-β-cyclodextrin was added thereto. The mixture was stirred and reacted at 25° C. for 8 h, dialyzed for 72 h, and freeze-dried to obtain a sustained-release carrier.

[0053] Example 1

[0054] A method for preparing a plant-derived composition for aquatic product prevention and treatment, comprising the following preparation steps:

[0055] At 20°C, 0.1 parts of peppermint oil, 0.5 parts of eucalyptus oil, 0.2 parts of chili oil, 0.3 parts of thymol, 0.1 parts of cinnamaldehyde and 0.5 parts of shanshan oil were mixed in parts by mass and stirred for 15 minutes to obtain a mixture, 0.3 parts of a sustained-release carrier were added to the mixture and stirred for 20 minutes, and then 0.3 parts of a sustained-release carrier were added to the mixture and stirred for 20 minutes, and finally 8 parts of an emulsifier, 4 parts of a co-solvent and 65 parts of water were added and stirred evenly to obtain a plant-based composition.

[0056] The sustained-release carrier used is obtained from Preparation Example 1; the emulsifier is composed of soybean lecithin, sucrose fatty acid ester and Span 80 in a mass ratio of 1:3:1.

[0057] Example 2

[0058] A method for preparing a plant-derived composition for aquatic product prevention and treatment, comprising the following preparation steps:

[0059] At 30°C, 0.5 parts of peppermint oil, 1 part of eucalyptus oil, 0.6 parts of chili oil, 0.6 parts of thymol, 0.3 parts of cinnamaldehyde and 1 part of shanshan oil were mixed in parts by mass and stirred for 30 minutes to obtain a mixture. 1 part of a sustained-release carrier was added to the mixture and stirred for 30 minutes. Then 1 part of the sustained-release carrier was added to the mixture and stirred for 30 minutes. Finally, 18 parts of an emulsifier, 14 parts of a cosolvent and 85 parts of water were added and stirred evenly to obtain a plant-based composition.

[0060] The sustained-release carrier used is obtained from Preparation Example 1; the emulsifier is composed of soybean lecithin, sucrose fatty acid ester and Span 80 in a mass ratio of 2:9:2.

[0061] Example 3

[0062] A method for preparing a plant-derived composition for aquatic product prevention and treatment, comprising the following preparation steps:

[0063] At 30°C, 0.3 parts of peppermint oil, 0.8 parts of eucalyptus oil, 0.4 parts of chili oil, 0.4 parts of thymol, 0.2 parts of cinnamaldehyde and 0.8 parts of shanshan oil were mixed in parts by mass and stirred for 20 minutes to obtain a mixture, 0.75 parts of a sustained-release carrier were added to the mixture and stirred for 25 minutes, and then 0.75 parts of a sustained-release carrier were added to the mixture and stirred for 25 minutes, and finally 13 parts of an emulsifier, 9 parts of a co-solvent and 75 parts of water were added and stirred evenly to obtain a plant-based composition.

[0064] The sustained-release carrier used is obtained from Preparation Example 1; the emulsifier is composed of soybean lecithin, sucrose fatty acid ester and Span 80 in a mass ratio of 1:8:1.

[0065] Example 4

[0066] A method for preparing a plant-derived composition for aquatic product prevention and treatment, comprising the following preparation steps:

[0067] At 30°C, 0.3 parts of peppermint oil, 0.8 parts of eucalyptus oil, 0.4 parts of chili oil, 0.4 parts of thymol, 0.2 parts of cinnamaldehyde and 0.8 parts of shanshan oil were mixed in parts by mass and stirred for 20 minutes to obtain a mixture. Finally, 13 parts of emulsifier, 9 parts of co-solvent and 75 parts of water were added and stirred evenly to obtain a plant-based composition.

[0068] The emulsifier consists of soybean lecithin, sucrose fatty acid ester and Span 80 in a mass ratio of 1:8:1.

[0069] Example 5

[0070] A method for preparing a plant-derived composition for the prevention and treatment of aquatic products, the specific implementation method is the same as that of Example 3, except that the slow-release carrier used is obtained from Preparation Example 2.

[0071] Example 6

[0072] A method for preparing a plant-derived composition for the prevention and treatment of aquatic products, the specific implementation method is the same as that of Example 3, except that the slow-release carrier used is obtained from Preparation Example 3.

[0073] Example 7

[0074] A method for preparing a plant-derived composition for the prevention and treatment of aquatic products, the specific implementation method is the same as that of Example 3, except that the slow-release carrier used is obtained from Preparation Example 4.

[0075] Example 8

[0076] A method for preparing a plant-derived composition for the prevention and treatment of aquatic products, the specific implementation method is the same as that of Example 3, except that the slow-release carrier used is obtained from Preparation Example 5.

[0077] Example 9

[0078] A method for preparing a plant-derived composition for the prevention and treatment of aquatic products, the specific implementation method is the same as that of Example 3, except that Span 80 and Tween 60 of equal mass and mass ratio of 4:6 are used instead of the emulsifier.

[0079] Example 10

[0080] A method for preparing a plant-derived composition for aquatic product control, the specific implementation method is the same as that of Example 3, except that an equal mass of hydroxypropyl-β-cyclodextrin is used instead of a sustained-release carrier.

[0081] Embodiment 11

[0082] A method for preparing a plant-derived composition for aquatic product control, the specific implementation method is the same as that of Example 3, except that no emulsifier is added.

[0083] Performance Testing

[0084] The plant-derived compositions obtained in the examples and comparative examples of the present invention were used in aquaculture anthelmintic / insect inhibition tests.

[0085] 1. Research location: Experimental ponds for tilapia and shrimp farming in a certain area of ​​Guangdong (such as Figure 1-3 ), 12 tilapia test ponds and 12 shrimp test ponds were set up respectively, the tilapia culture density was 1500 tails / mu, and the shrimp culture density was 300 tails / m3. Test pond No. 1 was a blank control group, that is, only feed was used for feeding (including tilapia blank control group and shrimp blank control group respectively); test ponds No. 2-12 were test ponds of the plant source composition in Examples 1-11 (including tilapia experimental group and shrimp experimental group respectively).

[0086] 2. Usage: Based on the volume of water in the pond, the plant-derived composition obtained in each embodiment is sprayed into the corresponding test pond at a dosage of 0.2 mg / L, and sprayed continuously for 3 days. At the same time, 0.5 kg is added to the feed for every 100 kg of feed, and the feeding is continued for 3 days.

[0087] 3. Detection method: Use microscopic observation method to detect the parasite inhibition rate of the plant-derived composition on tilapia. Randomly take the gill tissues of 20 tilapia in each test pond and place them on a slide, add 4 drops of physiological saline, cover with a cover glass, slightly flatten, and observe under an ordinary microscope. Use a microscope to observe and record the wheelworms and myxosporeans. Observe and count 3 fields of view on one slide, calculate the average number in each field of view, and calculate the inhibition rate (%) of the plant-derived composition on wheelworms and myxosporeans: inhibition rate = (the number of each parasite in the gills of tilapia in the blank control group - the number of each parasite in the gills of tilapia in each test pond) / the number of each parasite in the gills of tilapia in the blank control group × 100%.

[0088] The PCR method was used to detect the inhibition rate of the plant-derived composition on parasites in shrimp. The gill tissues (0.1 g) of 40 shrimps in each test pond were randomly taken, and DNA was extracted according to the instructions of the DNA extraction kit, and then PCR amplification was performed. The PCR amplification products were detected by agarose gel electrophoresis, and the number of samples in the experimental group and the control group that were positive for microsporidia detected by PCR was recorded. The inhibition rate (%) of the plant-derived composition on microsporidia in shrimp was calculated as follows: inhibition rate = (positive rate of the control group - positive rate of the experimental group) / positive rate of the control group × 100%.

[0089] 4. Effect of use: Before use, the tilapia and shrimp in each pond had low food intake and slow growth. After using the plant-derived composition, the food intake of the tilapia and shrimp recovered and their activities returned to normal.

[0090] The specific results are shown in Table 1.

[0091] Table 1

[0092]

[0093] As can be seen from Table 1, the plant-derived compositions prepared in Examples 1-3 and 5 have a high inhibition rate on wheelworms and myxosporeans in tilapia, and microsporidia in shrimp. Compared with Example 3, in Example 4, since no sustained-release carrier was added, the release rate of the effective substances in the system was faster, which was not conducive to the absorption by tilapia and shrimp, and the inhibition rate of each parasite by the prepared plant-derived composition was reduced; the preparation conditions of the sustained-release carrier used in Examples 6-8 were changed, and the structure of the sustained-release carrier may be changed, and the release rate of the effective ingredients in the system was changed, which was not conducive to the absorption by tilapia and shrimp, resulting in different degrees of reduction in the inhibition rate of parasites in their bodies; the composition of the emulsifier used in Example 9 was changed, which had an effect on the system. The emulsification effect of various oil components changes, which may make some effective ingredients unavailable to tilapia and shrimp, reducing the efficacy; in Example 10, hydroxypropyl-β-cyclodextrin is used instead of the sustained-release carrier, and the sustained-release effect of hydroxypropyl-β-cyclodextrin on the effective ingredients is weaker than that of the sustained-release carrier of the present invention, which affects the efficacy of the plant-based composition and thus reduces its inhibition rate on parasites; in Example 11, no emulsifier is added, which may cause aggregation and stratification in the plant-based composition, making it impossible to disperse evenly in water, reducing the effect on parasites, and resulting in poor inhibition of parasites.

[0094] The above is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present application. Although the present application is disclosed as above in the preferred embodiment, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution.

Claims

1. A plant-derived composition for the prevention and treatment of aquatic products, characterized in that: According to the weight percentage, it includes the following raw materials: 0.1-0.5 parts of peppermint oil, 0.5-1 parts of eucalyptus oil, 0.2-0.6 parts of chili oil, 0.3-0.6 parts of thymol, 0.1-0.3 parts of cinnamaldehyde, 0.5-1 parts of changshan oil, 8-18 parts of emulsifier, 4-14 parts of cosolvent, and 65-85 parts of water.

2. The plant-derived composition according to claim 1, characterized in that The raw materials also include 0.6-2 parts by weight of a sustained-release carrier.

3. The plant-derived composition according to claim 2, characterized in that: The preparation steps of the sustained-release carrier are as follows: (1) placing chitosan monomer in deionized water and adjusting the pH thereof to 4-5 to obtain solution 1; (2) placing oligomeric hyaluronic acid in deionized water, and adding an activator thereto to obtain solution 2; (3) Add solution 2 to solution 1 under stirring at 20-30° C., stir and react for 10-16 h, then add hydroxypropyl-β-cyclodextrin, stir and react at 20-30° C. for 6-10 h, dialyze, and freeze-dry to obtain a sustained-release carrier.

4. The plant-derived composition according to claim 3, characterized in that: The chitosan monomer is N-acetyl-D-glucosamine or D-glucosamine.

5. The plant-derived composition according to claim 3, characterized in that: The molar ratio of the chitosan monomer to the oligomeric hyaluronic acid is (25-28):

1.

6. The plant-derived composition according to claim 3, characterized in that: The ratio of the mass of the hydroxypropyl-β-cyclodextrin to the total mass of the chitosan monomer and the oligomeric hyaluronic acid is (0.6-0.9):

1.

7. The plant-derived composition according to claim 1, characterized in that: The emulsifiers include soy lecithin, sucrose fatty acid esters and Span 80.

8. The plant-derived composition according to claim 7, characterized in that: The HLB value of the emulsifier is 8-13.

9. A method for preparing the plant-derived composition according to any one of claims 2 to 8, characterized in that: The method comprises the following preparation steps: At 20-30°C, peppermint oil, eucalyptus oil, chili oil, thymol, cinnamaldehyde and shanshan oil are mixed and stirred for 15-30 minutes to obtain a mixture, and then a sustained-release carrier is added to the mixture twice, and each time the sustained-release carrier is added, the mixture is stirred for 20-30 minutes. Finally, an emulsifier, a cosolvent and water are added, and the mixture is stirred evenly to obtain a plant-derived composition.

10. An application of the plant-derived composition according to any one of claims 1 to 8 in the field of preventing and controlling aquatic product parasites, characterized in that: The parasite inhibition rate of the plant-based composition on aquaculture animals is greater than 80%.

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