Aquatic feed prepared from traditional Chinese medicine residues and preparation method of aquatic feed

Abstract

The invention discloses an aquatic feed using traditional Chinese medicine residues and a preparation method thereof, and belongs to the field of aquatic feeds, and the preparation method comprises the following steps: carrying out enzymolysis on herba houttuyniae residues, carrying out steam distillation on an enzymolysis product, removing volatile components, adding a microbial inoculum to ferment a distillation retentate, drying a fermentation product, mixing the fermentation product with nutrient substances, and powdering to obtain a core material; coating the surface of the core material with the Chinese yam dreg slurry, and drying to obtain core-shell particles; taking the core-shell particles as raw materials, and forming to obtain the aquatic feed. According to the method, cordate houttuynia herb residue fibers are subjected to enzymolysis to form carbohydrates with smaller molecules, then distillation is carried out to weaken the special smell of cordate houttuynia herb residues, fermentation is continued to deeply degrade the enzymolysis product, so that the fermentation product is more easily digested by fishes, a core material is coated with Chinese yam herb residue slurry, and a shell layer formed by starch is utilized to cover part of the smell of the cordate houttuynia herb residues; according to the method, the cordate houttuynia herb residues and the Chinese yam herb residues can be recycled, and the prepared feed is good in palatability and easy to digest by fishes.

Description

Technical Field

[0001] The present invention relates to an aquatic feed using Chinese medicine residues and a production method thereof, belonging to the field of aquatic feeds. Background Art

[0002] With the large-scale and intensive development of the aquaculture industry, the disease losses caused by pathogens seriously affect the healthy development of the aquaculture industry.

[0003] Existing research shows that active ingredients such as polysaccharides and oligosaccharides in Chinese herbal medicines can improve animal immunity and enhance antiviral functions. Chinese medicine residues are the residues after extracting the active ingredients from Chinese herbal medicines. After extraction of Chinese herbal medicines, there are still about 30% of the medicinal active ingredients remaining in the residues. In addition, Chinese medicine residues also contain a large amount of nutrients such as polysaccharides, oligosaccharides and polypeptides, and still have high utilization value. Applying Chinese medicine residues to aquatic feeds is expected to reduce the use of antibiotics and fishery drugs. In recent years, with the development of the Chinese medicine industry, the discharge of Chinese medicine residues has also increased rapidly. According to statistics, the annual discharge of Chinese medicine residues in the country exceeds 30 million tons. Traditional treatment methods for Chinese medicine residues include stacking, incineration and burial, etc., which will not only cause environmental pollution, but also cause great waste of Chinese medicine residue resources.

[0004] In existing research, when Chinese medicine residues are mixed into fish feeds for feeding, although the fish feeds mixed with Chinese medicine residues help to improve the disease resistance of fish populations, the weight gain rate of fish populations slows down significantly. It is speculated that this is because in addition to still containing a small amount of active substances that help to improve disease resistance in the Chinese medicine residues after one extraction, there are also some components that are not conducive to feeding fish, such as anti-nutritional factors such as saponins, lectins, and protease inhibitors. Some will cause fish physiological discomfort and decreased digestive ability, and some will affect palatability due to smell and taste.

[0005] For example, Houttuynia cordata has antibacterial and antiviral effects. Even the Houttuynia cordata residues after one extraction still have a small amount of active substances with disease-resistant effects remaining. Existing research has shown that Houttuynia cordata has disease-resistant effects not only on humans, but also on farmed animals. However, there are some anti-nutritional factors in Houttuynia cordata; and its special smell is difficult to be actively accepted by animals. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the present invention provides an aquatic feed using Chinese medicine residues and a production method thereof. By pre-treatment, some anti-nutritional factors in the Chinese medicine residues are removed, so that the palatability of the feed mixed with the active ingredients of the Chinese medicine residues is improved, and it is easier to be digested by fish.

[0007] The technical solution adopted by the present invention to solve its technical problems is as follows: In a first aspect, the present application provides a production method of an aquatic feed using Chinese medicine residues, including the following steps: The houttuynia herb residue is enzymatically hydrolyzed with cellulase to obtain a hydrolysate; The hydrolysate is subjected to steam distillation to remove volatile components, obtaining a residue; A microbial agent is added to the residue for fermentation, and the fermented mixed system is dried to obtain an immobilized fermented product; The immobilized fermented product is mixed with nutrients and pulverized to obtain a core material; A yam residue slurry is prepared, and the yam residue slurry is coated on the surface of the core material and dried to obtain core-shell particles; Using the core-shell particles as raw materials, the aquatic feed using the herb residue in the application is formed.

[0008] The method for preparing the aquatic feed using the herb residue provided in this application enzymatically hydrolyzes the fibers of the houttuynia herb residue into smaller molecules of carbohydrates, such as hemicellulose, polysaccharides, etc.; then distillation weakens the special smell of the houttuynia herb residue, retains the disease-resistant active ingredients, avoids affecting the palatability of the feed, and ensures that the flavonoids with antioxidant, anti-inflammatory, and antiviral biological activities remaining in the houttuynia herb residue can be utilized; the cellulase is inactivated incidentally during the distillation process to avoid excessive enzymatic hydrolysis caused by continuous action, which is beneficial to controlling the degree of degradation; continuing to ferment the residue can further degrade the enzymatic hydrolysis products and degrade anti-nutritional factors such as saponins, making the immobilized fermented product easier to be digested by fish; coating the core material with the yam residue slurry can utilize the starch of the yam residue as part of the nutrients of the feed and use the shell layer formed by the starch to cover part of the smell of the houttuynia herb residue, which is beneficial to improving the palatability of the feed.

[0009] Further, the step of enzymatically hydrolyzing the houttuynia herb residue with cellulase includes: The houttuynia herb residue is crushed into particles with a particle size of 0.5 mm to 1 mm, added to a phosphate buffer solution with a pH of 5.0 to 6.0, the cellulase is added, and stirred in an environment of 35°C to 40°C for 4 h to 6 h; the addition amount of the cellulase is equivalent to 1% to 2% of the mass of the houttuynia herb residue.

[0010] Crushing into small particles before enzymatic hydrolysis can increase the contact area between the enzyme and the herb residue, improve the enzymatic hydrolysis efficiency. Under this enzymatic hydrolysis condition, crude fiber can be effectively degraded, reducing the digestion burden of fish, and is beneficial to releasing disease-resistant active ingredients. At the same time, excessive enzymatic hydrolysis caused by long-term treatment is avoided, and a certain amount of dietary fiber is retained.

[0011] Further, the requirements for the steam distillation are 90°C to 95°C and a time of 2 h to 3 h.

[0012] At this temperature, the cellulase can be inactivated to avoid excessive enzymatic hydrolysis; and under this distillation requirement, it is beneficial to remove most of the volatile oils with strong odors such as decanoyl acetaldehyde and decanal, and minimize the loss of flavonoid compounds such as quercetin and isoquercitrin.

[0013] Furthermore, the bacterial agent includes Clostridium butyricum.

[0014] Clostridium butyricum can ferment using the enzymatic hydrolysis product as a substrate, and continue to degrade the enzymatic hydrolysis substrate into smaller molecular sugars, which is beneficial to become the nutrients easily absorbed in the feed. At the same time, Clostridium butyricum can act as a probiotic in the fish intestine to improve the digestive ability of fish.

[0015] Furthermore, the requirements for the fermentation are: a closed environment at 30°C to 35°C, maintaining the pH at 4.5 to 5.5 with a phosphate buffer, and fermenting for 5d to 7d.

[0016] The weakly acidic environment can promote the directional metabolism of Clostridium butyricum. Combining this fermentation duration is beneficial to degrade or transform the anti-nutritional factors in Houttuynia herb residue as much as possible.

[0017] Furthermore, the steps of drying the fermented mixed system include: freeze-drying the fermented mixed system until the water content is below 10%; The steps of forming the aquatic feed using the core-shell particles as raw materials include: preparing an adhesive solution from an edible gel material, mixing the adhesive solution and the core-shell particles, and forming the aquatic feed using the Chinese medicine residue.

[0018] During the whole process of treating the fermentation product to become part of the feed, avoid too high temperature, adopt freeze-drying to dry the fermentation product, and at the same time avoid traditional conditioning, which is beneficial to retain the activity of Clostridium butyricum in the feed.

[0019] Furthermore, the edible gel material is at least one of agar, gelatin, and gellan gum.

[0020] These materials are non-toxic for food use, can quickly form a firm gel at 40°C to 70°C, and bonding the core-shell particles to form can avoid using the traditional feed conditioning process and retain the activity of microorganisms in the fermentation step.

[0021] Furthermore, the core material includes 20% to 70% fish meal, 20% to 50% soybean meal, 3% to 15% oil, 2% to 20% of the immobilized fermentation product, and 0.5% to 2% dipotassium hydrogen phosphate by mass; The core-shell particle includes a core material and a shell layer coated on the surface of the core material, and the mass of the shell layer of the core-shell particle accounts for 20% to 40% of the core-shell particle; By dry weight, the edible gel material accounts for 3% - 8% of the aquatic feed made from the Chinese medicine residues in the application.

[0022] Fish meal and soybean meal provide high-quality protein, and the oil supplements energy. The immobilized fermented product can avoid the decrease in palatability caused by excessive addition while ensuring the disease resistance function; at this mass ratio of the shell layer, the shell layer thickness effectively covers the residual smell of Houttuynia cordata residue in the Chinese medicine residues, and ensures an appropriate starch content in the feed; the dosage of the gel material achieves a good balance in terms of bonding strength and the proportion of other nutritional components.

[0023] Furthermore, the steps of preparing the Chinese yam residue slurry, coating the Chinese yam residue slurry on the surface of the core material, and drying to obtain the core-shell particles include: Steaming the Chinese yam residues, then placing them in an environment of 1°C - 4°C for more than 12 hours, sieving after pulverization, adding 3 - 5 times the mass of water to make a slurry to obtain the Chinese yam residue slurry, and adding 2 - 5 parts of calcium stearate per 100 parts of the Chinese yam residue slurry; Spraying and coating the Chinese yam residue slurry on the surface of the core material; Drying with hot air at 40°C - 50°C to obtain the core-shell particles.

[0024] After the first extraction, the Chinese yam residues still have antinutritional factors such as calcium oxalate and dioscorine. Steaming the Chinese yam residues can remove a large amount of antinutritional factors, and then in a low-temperature environment, the starch undergoes a certain degree of retrogradation, which is convenient for subsequent pulverization and pulping. Coating with the spraying method and drying with relatively low-temperature hot air can retain the activity of the microorganisms in the core material.

[0025] In the second aspect, the present application provides an aquatic feed made from Chinese medicine residues, which is made by the method for making an aquatic feed made from Chinese medicine residues in the first aspect.

[0026] The obtained aquatic feed has better nutritional value and biological activity, can utilize the active ingredients remaining in the Chinese medicine residues to enhance the immunity of fish, is beneficial to reducing the use of antibiotics and fishery drugs, and at the same time improves the palatability and digestion and absorption efficiency of the feed.

[0027] The beneficial effects of the present invention are as follows: The present invention enzymatically hydrolyzes the fibers of Houttuynia cordata residues into carbohydrates with smaller molecules, and then distills to weaken the special smell of Houttuynia cordata residues, avoiding affecting the palatability of the feed, while retaining the active ingredients in Houttuynia cordata residues. At the same time, the cellulase is inactivated, and continuous fermentation can further degrade the enzymatic hydrolysis products and degrade antinutritional factors such as saponins, making the fermentation products easier to be digested by fish. Coating the core material with Chinese yam residue slurry and using the shell layer formed by starch to cover part of the smell of Houttuynia cordata residues is beneficial to improving the palatability of the feed. This method can recycle Houttuynia cordata residues and Chinese yam residues, and the prepared feed has good palatability and is easy for fish to digest.

[0028] Other features and advantages of the present application will be described in the subsequent specification, and in part will be obvious from the specification, or will be understood by implementing the present application. The objectives and other advantages of the present application can be achieved and obtained by the structures specifically pointed out in the written specification and the drawings. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of an aquatic feed applying Chinese medicine residues provided by an embodiment of the present application.

[0030] Figure 2 It is a schematic structural diagram of a core-shell particle in an aquatic feed applying Chinese medicine residues provided by an embodiment of the present application.

[0031] Reference numerals: 1, core-shell particle; 11, shell layer; 12, core material; 2, gel. Detailed Embodiments

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts fall within the scope of protection of the present invention.

[0033] It should be understood that, on the premise of no conflict, any and all implementation schemes of the present invention can be combined with the technical features in any other implementation scheme or multiple other implementation schemes to obtain additional implementation schemes. The present invention includes such additional implementation schemes obtained by combination.

[0034] Unless otherwise specified, all technical terms and scientific terms used herein have the standard meanings in the field to which the claimed subject matter belongs. If there are multiple definitions for a certain term, the definition in this article shall prevail.

[0035] The embodiment of the present application provides a method for preparing an aquatic feed applying Chinese medicine residues, including the following steps: S1: Enzymatically hydrolyze Houttuynia cordata residues with cellulase to obtain a hydrolyzate.

[0036] S2: Perform steam distillation on the hydrolyzate to remove volatile components and obtain a residue.

[0037] S3: Add a microbial agent to the residue for fermentation, and dry the fermented mixed system to obtain an immobilized fermented product.

[0038] S4: Mix and powder the immobilized fermented product with nutrients to obtain a core material.

[0039] S5: Prepare the yam residue slurry, coat the surface of the core material with the yam residue slurry, and dry to obtain core-shell particles.

[0040] S6: Use the core-shell particles as raw materials to form aquatic feed using the medicinal residues.

[0041] In step S1, through cellulase enzymatic hydrolysis treatment, the fibers in the houttuynia cordata residue can be effectively degraded, the crude fiber content can be reduced, and most of the fibers can be degraded into hemicellulose, polysaccharides, disaccharides, etc., improving the availability of its nutritional components. Cellulose is an important component of the plant cell wall, and enzymatic hydrolysis treatment is beneficial to releasing the residual active components in the houttuynia cordata residue, such as flavonoids, oligosaccharides, etc. These components help to improve the functionality of the aquatic feed and enhance the immunity and disease resistance of fish.

[0042] In step S2, most of the volatile oils that produce the special smell of houttuynia cordata in the houttuynia cordata residue, such as decanoyl acetaldehyde, decanal, etc., are removed by steam distillation. It can effectively remove the smell and avoid affecting the palatability of the fish feed, and retain the bioactive flavonoid components such as quercetin and isoquercitrin. These compounds have biological activities such as antioxidant, antiviral, and anti-inflammatory, which help to enhance the health and disease resistance of fish. Moreover, the high temperature during distillation inactivates the cellulase, terminates the enzymatic hydrolysis reaction, avoids over-enzymatic hydrolysis, is beneficial to controlling the degree of fiber degradation, and retains a small amount of dietary fiber.

[0043] In step S3, through the fermentation of the microbial agent, carbohydrates such as polysaccharides are further degraded, and antinutritional factors in the residue, such as saponins, lectins, etc., are degraded.

[0044] In step S5, as a coating material, the starch contained in the yam residue can form a shell layer, covering the smell of the houttuynia cordata residue in the core material to a certain extent, thus improving the palatability of the feed. At the same time, the beneficial components of the yam residue can be utilized as nutritional substances for the feed. For example, in addition to starch, the yam residue also contains rich minerals, various amino acids, as well as a small amount of phenolic compounds and flavonoid substances, which have strong antioxidant effects, help to reduce the oxidative stress response in fish, protect cells from free radical damage, and thus improve the health level and survival rate of fish.

[0045] The specific steps of step S1 include: Crush the houttuynia cordata residue into particles with a particle size of 0.5 mm to 1 mm, add it to a phosphate buffer with a pH of 5.0 to 6.0, add cellulase, control the enzyme concentration to be 500 IU / kg to 2000 IU / kg (kg is the weight unit of the houttuynia cordata residue), and stir in an environment of 35°C to 40°C for 4 h to 6 h; the addition amount of cellulase is equivalent to 1% to 2% of the mass of the houttuynia cordata residue.

[0046] Crush the Houttuynia cordata residue to increase the contact area between the residue, phosphate buffer solution and cellulase. Under such enzymatic hydrolysis conditions, crude fiber can be degraded, the structure of the Houttuynia cordata residue becomes loose, more flavonoids are released, and at the same time, more anti-nutritional factors such as saponins are released, which are convenient for degradation in subsequent fermentation steps, and the enzyme activity is maintained stable to ensure the efficient progress of the enzymatic hydrolysis reaction.

[0047] The specific requirements for the distillation in step S2 are 90°C - 95°C and the time is 2h - 3h.

[0048] Such temperature and time conditions can effectively volatilize volatile oils such as decanoyl acetaldehyde and decanal with strong odors in the Houttuynia cordata residue, removing most of the odor components that affect the palatability of the feed, and at the same time avoiding the loss of effective components such as flavonoids caused by overheating. At the same time, this distillation process can just inactivate the cellulase that participated in the enzymatic hydrolysis before, avoiding the continuous action of cellulase causing excessive enzymatic hydrolysis of fibers, precisely controlling the degradation degree, ensuring the quality stability of the enzymatic hydrolysis products, being beneficial to subsequent processing, and retaining a certain amount of dietary fiber.

[0049] Preferably, the microbial agent in step S3 includes Clostridium butyricum. Clostridium butyricum can produce various enzymes during the fermentation process, which can further degrade the enzymatic hydrolysis products; the metabolites of Clostridium butyricum such as butyric acid help to regulate the intestinal microecological balance, inhibit the growth of harmful bacteria, improve the digestion ability and immunity of fish, enhance the absorption and utilization efficiency of nutrients in the feed by fish, and promote the healthy growth of fish. In addition, it can also be fermented in combination with other bacteria, such as lactic acid bacteria. If it is necessary to enhance the degradation (or transformation) effect of anti-nutritional factors such as saponins, Bacillus subtilis can be inoculated first for fermentation, and then Clostridium butyricum can be inoculated for fermentation. The "degrading saponins" mentioned in this application means decomposing saponins or converting one saponin into another saponin. The microbial agents that can degrade or transform saponins belong to the prior art, and this application does not discuss them in detail. Just purchase commercially available microbial agents during implementation.

[0050] Specifically, the requirements for fermentation are: a closed environment at 30°C - 35°C, maintaining the pH at 4.5 - 5.5 with phosphate buffer solution, adding 5g - 10g of microbial agent per 1kg of phosphate buffer solution, and fermenting for 5d - 7d.

[0051] Under acidic conditions, it is beneficial to degrade more saponins in the Houttuynia cordata residue and reduce the degradation of flavonoids. At the same time, the microbial community will gradually adapt to use flavonoids as a carbon source, and avoiding too long fermentation time can reduce the loss of flavonoids.

[0052] In some embodiments, the forming method in step S6 is extrusion with a screw extruder after conditioning. The shell layer of the core-shell particles is mainly composed of yam starch. After traditional conditioning treatment, the starch gelatinizes to produce an adhesive effect between the core-shell particles, so it can be formed.

[0053] Clostridium butyricum not only has the function of degrading enzymatic hydrolysates, but it is also a commonly used probiotic in aquatic feeds. Therefore, the fermentation step not only degrades the Houttuynia cordata herb residue into substances that are more easily absorbed by fish, but also promotes the reproduction of beneficial microorganisms, improves the health of fish intestines, and enhances the resistance of fish to pathogens.

[0054] To retain Clostridium butyricum in the fermentation product in the feed product, the entire process of processing the fermentation product into a part of the feed should avoid excessive temperature.

[0055] Correspondingly, in step S3, in addition to air drying, the dried fermented mixed system can also adopt freeze-drying technology to accelerate drying, and dry the fermented mixed system to a moisture content of less than 10%. Freeze-drying can retain the active ingredients in the fermentation product to the greatest extent, such as the metabolites produced by Clostridium butyricum and the nutrients produced during the fermentation process, and avoid the loss of active ingredients caused by high-temperature drying.

[0056] Step S6 does not adopt traditional conditioning, but instead prepares an adhesive solution from an edible gel material, mixes the adhesive solution and the core-shell particles, and forms an aquatic feed applying the herb residue. It is preferably a feed granulator, especially a feed pellet machine with a mold; if a screw extruder is to be used, the head temperature should be controlled below 65°C.

[0057] The structure of the obtained feed is as Figure 1 and Figure 2 shown. One feed includes multiple core-shell particles 1, and the core-shell particles 1 are filled with gel 2 for bonding between them. The core-shell particle 1 includes a core material 12 and a shell layer 11 wrapped on the surface of the core material 12, and the shell layer 11 is mainly composed of the starch of the Chinese yam herb residue. The flavonoids and polysaccharides in the fermentation product are relatively easy to lose in water. After being blocked by the double layers of the shell layer 11 and the gel 2, the nutrients and active substances with disease-resistant effects in the core material are not easily lost in the fish pond.

[0058] The edible gel material is at least one of agar, gelatin, and gellan gum. Among them, agar and gellan gum have better effects and can extend the time for the feed to be dissolved in water. Specifically, the edible gel material accounts for 3% - 8% of the aquatic feed applying the herb residue, and the mass of the edible gel material is calculated based on dry weight.

[0059] The specific steps of step S5 include: S51: Steam the Chinese yam herb residue, then place it in an environment of 1°C - 4°C for more than 12 h, crush it and sieve it, add 3 - 5 times the mass of water to make a slurry to obtain a Chinese yam herb residue slurry, and add 2 - 5 parts of calcium stearate per 100 parts of the Chinese yam herb residue slurry.

[0060] S52: Spray and coat the Chinese yam herb residue slurry on the surface of the core material.

[0061] S53: Dry with hot air at 40°C to 50°C to obtain core - shell particles.

[0062] Currently, the methods for extracting medicinal components from Chinese yam are mostly organic solvent extraction. After one - time extraction, the Chinese yam residue still contains antinutritional factors such as calcium oxalate and dioscorine. Steaming the Chinese yam residue (for example, heating with atmospheric steam for 8 min to 15 min) can remove a large amount of antinutritional factors, and then making the starch partially retrograde in a low - temperature environment is convenient for subsequent pulverization and pulping. Pulverizing and sieving can remove the coarse fibers of the Chinese yam residue. Adding 3 to 5 times the mass of water for pulping in step S51 is based on the weight of the sieved particles.

[0063] Steps S52 to S53 can be specifically carried out in a fluidized - bed coating device. Using the low - temperature hot air of the fluidized - bed coating device, the starch slurry is evenly coated on the surface of the core material and dried to form a shell layer.

[0064] Adding a small amount of calcium stearate to the Chinese yam residue slurry can improve the stability and adhesion of the shell layer and prolong the dissolution time of the feed in water. At the same time, calcium stearate can supplement calcium elements for the feed, which is helpful for the bone and scale development of fish groups.

[0065] Specifically, the core - shell particles include a core material and a shell layer coated on the surface of the core material. The particle size of the core material formed by pulverization is 0.1 mm to 0.6 mm, and the thickness of the shell layer is 4 μm to 80 μm. This size is convenient for bonding multiple core - shell particles into one feed pellet and takes into account the starch content in the whole feed pellet. With the water - adding amount for pulping of 3 to 5 times the mass of the sieved particles, the thickness of this shell layer can be quickly dried and fixed in the fluidized - bed device.

[0066] The nutrients in step S4 can be a conventional fish - feed formula.

[0067] Preferably, the core material includes, by mass, 20% - 70% fish meal, 20% - 50% soybean meal, 3% - 15% oil, 2% - 20% immobilized ferment, and 0.5% - 2% dipotassium hydrogen phosphate. The oil can be fish oil, vegetable oil, etc. Dipotassium hydrogen phosphate can neutralize the acidity of the fermentation product, reconcile the sour taste of the fermentation product, improve the palatability of the feed, and provide phosphorus and potassium elements. Phosphorus promotes cell metabolism, and potassium helps with osmotic pressure regulation and growth and development, which is beneficial to promoting fish bone development and improving their overall health level.

[0068] The aquatic feed prepared from Chinese medicine residues in the embodiments of the present application can be used alone as the main feed. The aquatic feed prepared from Chinese medicine residues in the embodiments of the present application can also be used as a health care feed and mixed with conventional feeds. For example, during the breeding process, the pond is sampled regularly, and the liver color and intestinal health status are examined by laparotomy. The mixing ratio of the health care feed is adjusted according to the health condition of the fish. The mixing ratio of the health care feed and the conventional feed can be adjusted within the range of 1:10 to 10:1.

[0069] Example 1 The Houttuynia cordata residue (provided by Guangdong Yifang Pharmaceutical Co., Ltd.) was crushed into particles with a particle size of 0.5 mm to 1 mm, and a phosphate buffer solution with a pH of 5.0 to 6.0 was added until the Houttuynia cordata residue was completely submerged. Cellulase (Shenzhen Lefu Biotechnology Co., Ltd.) was added, and the mixture was stirred in an environment of 35°C to 40°C for 4 h. 1.5 g of cellulase was added per 100 g of Houttuynia cordata residue.

[0070] The enzymatic hydrolysate was subjected to steam distillation at a distillation temperature of 90°C to 95°C for 2.5 h to remove volatile components, and a residue was obtained.

[0071] A microbial agent was added to the residue, and the pH was maintained at 4.5 to 5.5 with a phosphate buffer solution. The mixture was fermented in a closed environment at 30°C to 35°C for 7 d. The microbial agent was Clostridium butyricum (Weifang Yihao Biotechnology Co., Ltd.), and 5 g was added per 1 kg of phosphate buffer solution. The fermented mixed system was dried to a moisture content of less than 10% to obtain an immobilized fermented product.

[0072] The immobilized fermented product was mixed with nutrients and pulverized to obtain a core material with a particle size distribution of 0.3 mm to 0.6 mm. The core material included 20% fish meal, 50% soybean meal, 15% fish oil, 14.2% immobilized fermented product, and 0.8% dipotassium hydrogen phosphate by mass.

[0073] The steamed Chinese yam residue (provided by Guangdong Yifang Pharmaceutical Co., Ltd.) was placed in an environment of 1°C to 4°C for 12 h, pulverized and sieved, and then 5 times the mass of water was added to make a slurry to obtain a Chinese yam residue slurry. 3 parts of calcium stearate were added per 100 parts of the Chinese yam residue slurry.

[0074] The Chinese yam residue slurry was sprayed and coated on the surface of the core material, and then dried to obtain core-shell particles with a shell layer thickness of 0.05 mm to 0.075 mm.

[0075] Using the core-shell particles as raw materials, after conditioning, they were formed by a screw extruder to obtain the aquatic feed prepared from Chinese medicine residues in Example 1, which was a fish feed for adult fish with a diameter of about 3 mm and a length of about 5 mm.

[0076] Example 2 The Houttuynia cordata residue (provided by Guangdong Yifang Pharmaceutical Co., Ltd.) was crushed into particles with a particle size of 0.5 mm to 1 mm, and a phosphate buffer solution with a pH of 5.0 to 6.0 was added until the Houttuynia cordata residue was completely submerged. Cellulase (Shenzhen Lefu Biotechnology Co., Ltd.) was added, and the mixture was stirred in an environment of 35°C to 40°C for 5 h. 1 g of cellulase was added per 100 g of Houttuynia cordata residue.

[0077] The enzymatic hydrolysate was subjected to steam distillation at a distillation temperature of 90°C to 95°C for 2 h to remove volatile components, and a residue was obtained.

[0078] A bacterial agent was added to the residue, and the pH was maintained at 4.5 to 5.5 with a phosphate buffer solution. Fermentation was carried out in a closed environment at 30°C to 35°C for 7 d. The bacterial agent was Clostridium butyricum (Weifang Yihao Biotechnology Co., Ltd.), and 5 g was added per 1 kg of phosphate buffer solution. The fermented mixed system was freeze-dried until the water content was below 10% to obtain an immobilized fermented product.

[0079] The immobilized fermented product was mixed with nutrients and pulverized to obtain a core material with a particle size distribution of 0.3 mm to 0.6 mm. The core material included 22% fish meal, 48.5% soybean meal, 13% fish oil, 15% immobilized fermented product, and 1.5% dipotassium hydrogen phosphate by mass.

[0080] The steamed Chinese yam residue (provided by Guangdong Yifang Pharmaceutical Co., Ltd.) was placed in an environment of 1°C to 4°C for 12 h, then crushed and sieved, and 3 times the mass of water was added to make a slurry to obtain a Chinese yam residue slurry. 2 parts of calcium stearate were added per 100 parts of Chinese yam residue slurry.

[0081] The Chinese yam residue slurry was sprayed and coated on the surface of the core material using a fluidized bed coating device.

[0082] It was dried with air at 40°C to 50°C in the fluidized bed coating device to obtain core-shell particles with a shell layer thickness of 0.05 mm to 0.075 mm.

[0083] Agar was formulated into an adhesive solution, and the weight of the agar solute was equivalent to 5% of the weight of the core-shell particles. The adhesive solution and the core-shell particles were mixed and pressed with a feed forming machine to obtain the aquatic feed using the Chinese yam residue in Example 2, which was a fish feed with a short axis of about 3 mm and a long axis of about 5 mm.

[0084] Comparative Example 1 The Herba Houttuyniae residue (provided by Guangdong Yifang Pharmaceutical Co., Ltd.) was crushed into particles with a particle size of 0.5 mm to 1 mm, and mixed with corn flour, fish meal, soybean meal, fish oil, calcium stearate, and potassium dihydrogen phosphate. Among them, by mass, corn flour accounted for 29%, fish meal accounted for 14%, soybean meal accounted for 35%, fish oil accounted for 10%, Herba Houttuyniae residue accounted for 10.5%, potassium dihydrogen phosphate accounted for 0.7%, and calcium stearate accounted for 0.8%. After conditioning, it was extruded with a screw extruder to obtain the adult fish feed of Comparative Example 1, with a diameter of about 3 mm and a length of about 5 mm.

[0085] A general grass carp feed was prepared by mixing 10 parts of fish meal, 10 parts of soybean meal, 40 parts of wheat bran, 30 parts of corn flour, 0.2 parts of compound minerals, 0.2 parts of compound vitamins, 0.1 part of Clostridium butyricum, and 9.5 parts of fish oil by mass. After conditioning, the general grass carp feed was obtained, which was an adult fish feed with a diameter of about 3 mm and a length of about 5 mm.

[0086] The water quality temperature of the aquaculture pond was maintained at 20°C to 28°C, pH = 6.5 to 7.5, and dissolved oxygen > 5 mg / L. 250 grass carps weighing 3 catties (1500 ± 20 g) were put into each of the four aquaculture ponds. They were fed once at 9:00 - 10:00 every day and once at 15:00 - 16:00 every day, and the daily feeding amount was 5% of the grass carp body weight.

[0087] The general grass carp feed was continuously fed in Pond No. 1.

[0088] In Pond No. 2, the mixed feed was fed on the first day, and the feed prepared in Example 1: general grass carp feed = 1:9. On the second day, the mixed feed was fed, and the feed prepared in Example 1: general grass carp feed = 2:8. On the third day, the mixed feed was fed, and the feed prepared in Example 1: general grass carp feed = 3:7. On the fourth day, the mixed feed was fed, and the feed prepared in Example 1: general grass carp feed = 4:6. On the fifth day, the mixed feed was fed, and the feed prepared in Example 1: general grass carp feed = 5:5. On the sixth day, the mixed feed was fed, and the feed prepared in Example 1: general grass carp feed = 6:4. On the seventh day, the mixed feed was fed, and the feed prepared in Example 1: general grass carp feed = 7:3. From then on, the mixed ratio was maintained every day (the feed prepared in Example 1: general grass carp feed = 7:3) for feeding.

[0089] On the first day, the mixed feed was fed to the grass carps in Pond No. 3, and the feed prepared in Example 2: general grass carp feed = 1:9. On the second day, the mixed feed was fed, and the feed prepared in Example 2: general grass carp feed = 2:8. On the third day, the mixed feed was fed, and the feed prepared in Example 2: general grass carp feed = 3:7. On the fourth day, the mixed feed was fed, and the feed prepared in Example 2: general grass carp feed = 4:6. On the fifth day, the mixed feed was fed, and the feed prepared in Example 2: general grass carp feed = 5:5. On the sixth day, the mixed feed was fed, and the feed prepared in Example 2: general grass carp feed = 6:4. On the seventh day, the mixed feed was fed, and the feed prepared in Example 2: general grass carp feed = 7:3. Thereafter, the mixed ratio (feed prepared in Example 2: general grass carp feed = 7:3) was maintained for feeding every day.

[0090] On the first day, the mixed feed was fed to the grass carps in Pond No. 4, and the feed prepared in Comparative Example 1: general grass carp feed = 1:9. On the second day, the mixed feed was fed, and the feed prepared in Comparative Example 1: general grass carp feed = 2:8. On the third day, the mixed feed was fed, and the feed prepared in Comparative Example 1: general grass carp feed = 3:7. On the fourth day, the mixed feed was fed, and the feed prepared in Comparative Example 1: general grass carp feed = 4:6. On the fifth day, the mixed feed was fed, and the feed prepared in Comparative Example 1: general grass carp feed = 5:5. On the sixth day, the mixed feed was fed, and the feed prepared in Comparative Example 1: general grass carp feed = 6:4. On the seventh day, the mixed feed was fed, and the feed prepared in Comparative Example 1: general grass carp feed = 7:3. Thereafter, the mixed ratio (feed prepared in Comparative Example 1: general grass carp feed = 7:3) was maintained for feeding every day.

[0091] After a total of 80 days of breeding, the weight gain rate and enteritis incidence rate of the grass carps cultured in each pond were detected, and the detection results are shown in Table 1 below.

[0092] Table 1 Pond No. 1 Pond No. 2 Pond No. 3 Pond No. 4 Weight gain rate 70.9% 72.1% 79.5% 53.4% Incidence of enteritis 7.2% 4.0% 3.6% 2.8% Comparing Pond No. 4 with Pond No. 1, it can be seen that adding traditional Chinese medicine residues can improve the disease resistance of grass carp against enteritis, but it will have a certain impact on the palatability of the feed. For example, the incidence of enteritis in Pond No. 4 is the lowest, but the fish grow slowly and the economic benefits are not high. The feed mixed with traditional Chinese medicine residues in Pond No. 2 and Pond No. 3 has little impact on the palatability after being treated by this application, which can be seen from both the weight gain rate and the feeding time after daily feeding. Comparing Pond No. 3 with Pond No. 1 and Pond No. 2, the incidence of enteritis is lower and the weight gain rate of the fish is greater. This shows that when only feeding with general grass carp feed, the fish are more vulnerable to diseases and fail to fully exert their growth potential. After applying traditional Chinese medicine residues, the incidence of digestive diseases in the fish decreases and the nutrient utilization rate is higher, so the fish gain weight faster. Comparing Pond No. 2 with Pond No. 3, the incidence of enteritis is similar, but the weight gain rate is not as high as that of Pond No. 3. The reason may be that the feed in Pond No. 3 allows more probiotics to survive in the fermentation products, which is more conducive to the fish fully absorbing nutrients during digestion. The incidence of enteritis in Pond No. 2 and Pond No. 3 is higher than that in Pond No. 4, probably because some disease-resistant components are inevitably lost during the distillation and fermentation processes. Next, the project team will continue to study how to retain more active ingredients while reducing the impact on palatability.

[0093] In summary, this solution is expected to improve the disease resistance and growth performance of fish, providing a new option for green prevention and control in the aquaculture industry.

[0094] In the description of this specification, the descriptions referring to terms such as "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the said embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0095] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A method for preparing aquatic feed using Chinese medicinal residues, characterized in that: The following steps are involved: Using cellulase to enzymolyze the Houttuynia cordata residue to obtain an enzymolyzate; Performing steam distillation on the enzymolyzate to remove volatile components and obtain a retentate; adding a bacterial agent to the retentate for fermentation, and drying the mixed system after fermentation to obtain an immobilized fermentation product; Mixing the immobilized fermentation product with nutrients and grinding them into powder to obtain a core material; Prepare yam residue slurry, coat the yam residue slurry on the surface of the core material, and dry to obtain core-shell particles; The core-shell particles are used as raw materials to form aquatic feed using the Chinese medicinal residue.

2. The method for producing aquatic feed using Chinese medicinal residues according to claim 1, characterized in that: The step of enzymolysis treatment of Houttuynia cordata residue with cellulase comprises: The Houttuynia cordata residue is crushed into particles with a particle size of 0.5 mm to 1 mm, added to a phosphate buffer with a pH of 5.0 to 6.0, and the cellulase is added, and stirred at 35° C. to 40° C. for 4 h to 6 h; the amount of the cellulase added is equivalent to 1% to 2% of the mass of the Houttuynia cordata residue.

3. The method for preparing aquatic feed using Chinese medicinal residues according to claim 1, characterized in that: The requirements for the steam distillation are 90°C~95°C and the time is 2h~3h.

4. The method for producing aquatic feed using Chinese medicinal residues according to claim 1, characterized in that: The bacterial agent includes Clostridium butyricum.

5. The method for producing aquatic feed using Chinese medicinal residues according to claim 4, characterized in that: The fermentation requirements are: a closed environment at 30°C to 35°C, maintaining the pH at 4.5 to 5.5 with a phosphate buffer, and fermenting for 5 to 7 days.

6. The method for producing aquatic feed using Chinese medicinal residues according to claim 4, characterized in that: The step of drying the fermented mixed system comprises: freeze-drying the fermented mixed system until the moisture content is below 10%; The step of using the core-shell particles as raw materials to mold the aquatic feed using the Chinese medicine residue comprises: preparing an edible gel material into a binder solution, mixing the binder solution and the core-shell particles, and molding the aquatic feed using the Chinese medicine residue.

7. The method for producing aquatic feed using Chinese medicinal residues according to claim 6, characterized in that: The edible gel material is at least one of agar, gelatin and gellan gum.

8. The method for producing aquatic feed using Chinese medicinal residues according to claim 6, characterized in that: The core material comprises, by mass, 20% to 70% fish meal, 20% to 50% soybean meal, 3% to 15% oil, 2% to 20% immobilized fermentation product, and 0.5% to 2% dipotassium hydrogen phosphate; The core-shell particle comprises a core material and a shell layer coated on the surface of the core material, and the mass of the shell layer of the core-shell particle accounts for 20% to 40% of the core-shell particle; Based on dry weight, the edible gel material accounts for 3% to 8% of the aquatic feed using the Chinese medicinal residue.

9. The method for producing aquatic feed using Chinese medicinal residues according to claim 1, characterized in that: The steps of preparing yam residue slurry, coating the yam residue slurry on the surface of the core material, and drying to obtain core-shell particles include: Steam the yam residue, place it in an environment of 1°C to 4°C for more than 12 hours, crush it, sieve it, add 3 to 5 times the weight of water to make pulp, and obtain the yam residue slurry, and add 2 to 5 parts of calcium stearate for every 100 parts of the yam residue slurry; Spraying the yam residue slurry to coat the surface of the core material; The core-shell particles are dried with air at 40° C. to 50° C.

10. An aquatic feed using Chinese medicinal residues, characterized in that: The aquatic feed is prepared by the method for preparing aquatic feed using Chinese medicinal residues as described in any one of claims 1 to 9.

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