Aquatic feed using traditional Chinese medicine residue and its preparation method

Abstract

This invention discloses an aquatic feed using traditional Chinese medicine residue and its preparation method, belonging to the field of aquatic feed. The preparation steps include: enzymatically hydrolyzing houttuynia cordata residue, steam distilling the enzymatic hydrolysate to remove volatile components, adding microbial agents to ferment the distillation residue, drying the fermentation product, mixing the fermentation product with nutrients and grinding it into powder to obtain a core material; coating the core material with yam residue slurry and drying it to obtain shell particles; and using the shell particles as raw material to form aquatic feed. The houttuynia cordata residue fiber is enzymatically hydrolyzed into smaller carbohydrate molecules, then distilled to reduce the special odor of the houttuynia cordata residue. Continued fermentation further degrades the enzymatic hydrolysate, making the fermentation product easier for fish to digest. Coating the core material with yam residue slurry utilizes the starch-formed shell to mask part of the houttuynia cordata residue odor, which helps improve feed palatability. This method can utilize both houttuynia cordata residue and yam residue as resources, and the resulting feed has good palatability and is easily digestible by fish.

Description

Technical Field

[0001] This invention relates to an aquatic feed using traditional Chinese medicine residue and its preparation method, belonging to the field of aquatic feed. Background Technology

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

[0003] Existing research indicates that the active ingredients in traditional Chinese medicine (TCM), such as polysaccharides and oligosaccharides, can enhance animal immunity and antiviral function. TCM residue is the residue left after the extraction of active ingredients from TCM herbs. After extraction, approximately 30% of the medicinal active ingredients remain in the residue. In addition, the residue contains a large amount of nutrients such as polysaccharides, oligosaccharides, and polypeptides, retaining significant utilization value. Applying TCM residue to aquatic feed is expected to reduce the use of antibiotics and veterinary drugs. In recent years, with the development of the TCM industry, the discharge of TCM residue has also increased rapidly. Statistics show that the annual discharge of TCM residue nationwide exceeds 30 million tons. Traditional methods of treating TCM residue include stockpiling, incineration, and landfilling, which not only lead to environmental pollution but also result in a significant waste of TCM residue resources.

[0004] Existing studies have shown that mixing traditional Chinese medicine residue into fish feed can improve the disease resistance of fish, but it also significantly slows down the weight gain of the fish. This is presumably because the residue, after one extraction, still contains not only small amounts of active substances that help improve disease resistance, but also some components that are detrimental to fish feeding, such as saponins, lectins, and protease inhibitors—anti-nutritional factors. Some of these can cause physiological discomfort and decreased digestive capacity in fish, while others affect palatability due to their odor and taste.

[0005] For example, houttuynia cordata has antibacterial and antiviral effects. Even after a single extraction, small amounts of active substances with disease-fighting properties remain in the residue. Existing research has shown that houttuynia cordata has disease-fighting effects not only on humans but also on farmed animals. However, houttuynia cordata contains some anti-nutritional factors; furthermore, its distinctive gases are difficult for animals to actively absorb. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention provides an aquatic feed using Chinese herbal medicine residue and its preparation method. The pretreatment removes some anti-nutritional factors from the Chinese herbal medicine residue, thereby improving the palatability of the feed mixed with the active ingredients of Chinese herbal medicine residue and making it easier for fish to digest.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] In a first aspect, this application provides a method for preparing aquatic feed using traditional Chinese medicine residue, comprising the following steps:

[0009] The residue of Houttuynia cordata was enzymatically hydrolyzed with cellulase to obtain the hydrolysate;

[0010] The enzymatic hydrolysate was subjected to steam distillation to remove volatile components, yielding a residue.

[0011] Add microbial agents to the residue for fermentation, and dry the fermented mixture to obtain an immobilized ferment.

[0012] The immobilized fermentation material is mixed with nutrients and ground into powder to obtain the core material;

[0013] Prepare a yam residue slurry, coat the core material with the yam residue slurry, and dry to obtain core-shell particles;

[0014] Using the core-shell particles as raw materials, the aquatic feed containing the Chinese herbal medicine residue is formed.

[0015] The method for preparing aquatic feed using traditional Chinese medicine residue provided in this application involves enzymatically hydrolyzing the cellulosic acid of Houttuynia cordata residue into smaller carbohydrate molecules, such as hemicellulose and polysaccharides. Distillation then reduces the distinctive odor of the residue while retaining disease-fighting active ingredients, avoiding impact on feed palatability, and ensuring the utilization of flavonoids with antioxidant, anti-inflammatory, and antiviral bioactivity remaining in the residue. The distillation process also inactivates cellulase, preventing excessive enzymatic hydrolysis and helping to control the degree of degradation. Further fermentation of the residue further degrades the enzymatic hydrolysates and degrades anti-nutritional factors such as saponins, making the immobilized fermented material easier for fish to digest. Coating the core material with yam residue slurry allows the starch from the yam residue to serve as part of the feed's nutritional components, and the starch-formed shell masks some of the odor of the Houttuynia cordata residue, thus improving feed palatability.

[0016] Furthermore, the step of enzymatically hydrolyzing the houttuynia cordata residue with cellulase includes:

[0017] The houttuynia cordata 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, and the cellulase is added. The mixture is stirred at 35°C to 40°C for 4 to 6 hours. The amount of cellulase added is equivalent to 1% to 2% of the mass of the houttuynia cordata residue.

[0018] Breaking the residue into small particles before enzymatic hydrolysis increases the contact area between the enzyme and the residue, improving the hydrolysis efficiency. Under these conditions, crude fiber can be effectively degraded, reducing the digestive burden on fish and facilitating the release of disease-fighting active ingredients. At the same time, it avoids excessive hydrolysis caused by prolonged processing and retains a certain amount of dietary fiber.

[0019] Furthermore, the steam distillation is required to be performed at 90℃~95℃ for 2h~3h.

[0020] At this temperature, cellulase can be deactivated, avoiding excessive enzymatic hydrolysis; and under these distillation conditions, it is beneficial to remove most of the strongly odorous volatile oils such as decanoyl acetaldehyde and decanal, and to minimize the loss of flavonoids such as quercetin and isoquercitrin.

[0021] Furthermore, the microbial agent includes Clostridium butyricum.

[0022] Clostridium butyricum can use enzymatic hydrolysates as substrates for fermentation, further degrading the hydrolysates into smaller sugar molecules, which are easily absorbed nutrients in feed. At the same time, Clostridium butyricum can act as a probiotic in the intestines of fish, improving their digestive capacity.

[0023] Furthermore, the fermentation requirements are: a closed environment at 30℃~35℃, pH maintained at 4.5~5.5 with phosphate buffer, and fermentation for 5~7 days.

[0024] A slightly acidic environment can promote the targeted metabolism of Clostridium butyricum. This fermentation duration is beneficial for maximizing the degradation or transformation of anti-nutritional factors in the residue of Houttuynia cordata.

[0025] Furthermore, the step of drying the fermented mixture includes: freeze-drying the fermented mixture until the moisture content is below 10%;

[0026] The step of using the shell particles as raw material to form the aquatic feed containing the applied traditional Chinese medicine residue includes: preparing an edible gel material into an adhesive solution, mixing the adhesive solution and the shell particles, and forming the aquatic feed containing the applied traditional Chinese medicine residue.

[0027] Throughout the process of processing the fermentation products into part of the feed, excessively high temperatures are avoided. The fermentation products are dried by freeze drying, while traditional conditioning is avoided, which helps to retain the activity of Clostridium butyricum in the feed.

[0028] Furthermore, the edible gelling material is at least one of agar, gelatin, and gellan gum.

[0029] These materials are non-toxic to food and can quickly form a strong gel at 40℃~70℃. Using this gel to bond core-shell particles can avoid the use of traditional feed conditioning processes and preserve the activity of microorganisms in the fermentation process.

[0030] Furthermore, the core material comprises, by weight, 20%–70% fishmeal, 20%–50% soybean meal, 3%–15% oil, 2%–20% of the immobilized fermented material, and 0.5%–2% dipotassium hydrogen phosphate;

[0031] The core-shell particle includes a core material and a shell layer covering the surface of the core material, wherein the shell layer accounts for 20% to 40% of the mass of the core-shell particle;

[0032] On a dry weight basis, the edible gel material accounts for 3% to 8% of the aquatic feed containing the Chinese herbal medicine residue used in the application.

[0033] Fishmeal and soybean meal provide high-quality protein, while oils supplement energy. Immobilized fermented products ensure disease resistance while avoiding excessive addition that could reduce palatability. At this shell mass ratio, this shell thickness effectively masks the residual odor of fishy herbal residue and ensures a moderate starch content in the feed. The amount of gelling material achieves a good balance between adhesive strength and the proportion of other nutrients.

[0034] Further, the step of preparing the yam residue slurry, coating the core material surface with the yam residue slurry, and drying to obtain core-shell particles includes:

[0035] Steam the yam residue, then place it in an environment of 1℃~4℃ for more than 12 hours, crush it and sieve it, add 3 to 5 times the weight of water to make a slurry, and add 2 to 5 parts of calcium stearate for every 100 parts of the yam residue slurry.

[0036] The yam residue slurry is sprayed and coated onto the surface of the core material;

[0037] The core-shell particles were obtained by drying with air at 40℃~50℃.

[0038] After the initial extraction, the yam residue still contains anti-nutritional factors such as calcium oxalate and yam alkaloids. Steaming the yam residue removes a large number of these anti-nutritional factors. Then, the starch undergoes a certain degree of retrogradation in a low-temperature environment, facilitating subsequent grinding and pulping. Coating with a spray method and drying with low-temperature hot air preserves the activity of microorganisms in the core material.

[0039] Secondly, this application provides an aquatic feed using traditional Chinese medicine residue, which is made by the aquatic feed preparation method using traditional Chinese medicine residue described in the first aspect.

[0040] The resulting aquatic feed has better nutritional value and biological activity. It can utilize the active ingredients remaining in the drug residue to enhance the immunity of fish, which helps to reduce the use of antibiotics and fish drugs, while improving the palatability and digestibility of the feed.

[0041] The beneficial effects of this invention are as follows: This invention enzymatically hydrolyzes the cellulase in the residue of Houttuynia cordata into carbohydrates with smaller molecules, and then distills it to reduce the special odor of the residue, avoiding affecting the palatability of the feed, while retaining the active ingredients in the residue. At the same time, it inactivates cellulase, and continued fermentation can further degrade the enzymatic hydrolysate and degrade anti-nutritional factors such as saponins, making the fermentation product easier for fish to digest. The core material is coated with yam residue slurry, and the starch-formed shell covers part of the odor of the residue, which helps to improve the palatability of the feed. This method can make resource utilization of Houttuynia cordata residue and yam residue, and the resulting feed has good palatability and is easy for fish to digest.

[0042] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of an aquatic feed using traditional Chinese medicine residue provided in an embodiment of this application.

[0044] Figure 2 This is a schematic diagram of the structure of shell particles in aquatic feed made from traditional Chinese medicine residue, provided in an embodiment of this application.

[0045] Reference numerals: 1. Core-shell particle; 11. Shell layer; 12. Core material; 2. Gel. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this invention.

[0047] It should be understood that, without conflict, any and all embodiments of the present invention can be combined with technical features of any other embodiment or multiple other embodiments to obtain other embodiments. The present invention includes such combinations to obtain other embodiments.

[0048] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter pertains. Where multiple definitions exist for a term, the definition herein shall prevail.

[0049] This application provides a method for preparing aquatic feed using traditional Chinese medicine residue, including the following steps:

[0050] S1: The residue of Houttuynia cordata was enzymatically hydrolyzed with cellulase to obtain the hydrolysate.

[0051] S2: The enzymatic hydrolysate is subjected to steam distillation to remove volatile components, resulting in a residue.

[0052] S3: Add microbial agents to the residue for fermentation, dry the fermented mixture, and obtain immobilized fermented material.

[0053] S4: Mix the immobilized fermentation material with nutrients and grind them into powder to obtain the core material.

[0054] S5: Prepare yam residue slurry, coat the core material surface with yam residue slurry, and dry to obtain core-shell particles.

[0055] S6: Using shell pellets as raw material, aquatic feed made from traditional Chinese medicine residue is obtained.

[0056] In step S1, enzymatic hydrolysis using cellulase effectively degrades the fiber in the residue of Houttuynia cordata, reducing the crude fiber content and breaking down most of the fiber into hemicellulose, polysaccharides, disaccharides, etc., thereby improving the bioavailability of its nutrients. Cellulose is an important component of plant cell walls, and enzymatic hydrolysis helps release residual active ingredients in the residue of Houttuynia cordata, such as flavonoids and oligosaccharides. These components help improve the functionality of aquatic feed and enhance the immunity and disease resistance of fish.

[0057] In step S2, steam distillation removes most of the volatile oils that produce the distinctive odor of houttuynia cordata, such as decanoyl acetaldehyde and decanal, from the herb residue. This effectively removes the odor, preventing it from affecting the palatability of the fish feed, while retaining bioactive flavonoids such as quercetin and isoquercitrin. These compounds possess antioxidant, antiviral, and anti-inflammatory activities, which help enhance the health and disease resistance of fish. Furthermore, the high temperature during distillation inactivates cellulase, terminating the enzymatic reaction and preventing over-enzymatic hydrolysis. This helps control the degree of fiber degradation and retains a small amount of dietary fiber.

[0058] In step S3, the polysaccharides and other carbohydrates are further degraded through fermentation with microbial agents, and anti-nutritional factors such as saponins and lectins in the medicinal residue are also degraded.

[0059] In step S5, the yam residue is used as a coating material. The starch it contains can form a shell, which can mask the odor of the fishy herb residue in the core material to a certain extent, thereby improving the palatability of the feed. At the same time, the beneficial components of the yam residue can be used as nutrients in the feed. For example, in addition to starch, yam residue also contains rich minerals and various amino acids, as well as a small amount of phenolic compounds and flavonoids, which have strong antioxidant effects. This helps to reduce oxidative stress in fish, protect cells from free radical damage, and thus improve the health and survival rate of fish.

[0060] The specific steps of step S1 include:

[0061] The residue of Houttuynia cordata was crushed into particles with a diameter of 0.5 mm to 1 mm and added to a phosphate buffer solution with a pH of 5.0 to 6.0. Cellulase was added and the enzyme concentration was controlled at 500 IU / kg to 2000 IU / kg (kg is the weight unit of Houttuynia cordata residue). The mixture was stirred at 35℃ to 40℃ for 4 to 6 hours. The amount of cellulase added was equivalent to 1% to 2% of the mass of Houttuynia cordata residue.

[0062] Crushing the residue of Houttuynia cordata increases the contact area between the residue and phosphate buffer and cellulase. Under these enzymatic hydrolysis conditions, crude fiber can be degraded, making the structure of the residue loose and releasing more flavonoids. At the same time, more anti-nutritional factors such as saponins are also released, which are easier to degrade in subsequent fermentation steps and maintain stable enzyme activity, ensuring that the enzymatic hydrolysis reaction proceeds efficiently.

[0063] The specific requirements for distillation in step S2 are 90℃~95℃ and 2h~3h.

[0064] The specific temperature and time conditions effectively volatilize the volatile oils such as decanoyl acetaldehyde and decanal in the fish mint residue, removing most of the odor components that affect feed palatability, while avoiding the loss of effective components such as flavonoids due to overheating. Simultaneously, this distillation process inactivates the cellulase involved in the enzymatic hydrolysis, preventing excessive fiber degradation caused by continued cellulase action. This precise control of the degradation degree ensures stable quality of the hydrolysate, facilitating subsequent processing and retaining a certain amount of dietary fiber.

[0065] Preferably, the microbial agent in step S3 includes *Clostridium butyricum*. *Clostridium butyricum* produces various enzymes during fermentation, which can further degrade enzymatic hydrolysis products. Metabolites of *Clostridium butyricum*, such as butyric acid, help regulate the intestinal microecological balance, inhibit the growth of harmful bacteria, improve the digestive capacity and immunity of fish, enhance the absorption and utilization efficiency of nutrients in feed, and promote healthy growth of fish. In addition, other microorganisms, such as lactic acid bacteria, can be used in conjunction with fermentation. To enhance the degradation (or transformation) effect on anti-nutritional factors such as saponins, *Bacillus subtilis* can be inoculated first for fermentation, followed by *Clostridium butyricum* fermentation. The term "degradation of saponins" in this application refers to the decomposition of saponins or the transformation of one saponin into another. Microbial agents capable of degrading or transforming saponins are existing technologies and will not be discussed in detail in this application; commercially available microbial agents can be purchased for implementation.

[0066] Specifically, the fermentation requirements are: a closed environment at 30℃~35℃, pH maintained at 4.5~5.5 with phosphate buffer, 5g~10g of bacterial agent added per 1kg of phosphate buffer, and fermentation for 5d~7d.

[0067] Under slightly acidic conditions, more saponins in the residue of houttuynia cordata are degraded, reducing the degradation of flavonoids. At the same time, the microbial community gradually adapts to using flavonoids as a carbon source, and avoiding excessively long fermentation times can reduce the loss of flavonoids.

[0068] In some embodiments, step S6 is performed by extruding the conditioned material using a screw extruder. The shell of the core-shell particles is mainly composed of yam starch. After conventional conditioning, the starch gelatinization causes adhesion between the core-shell particles, thus enabling them to be shaped.

[0069] Clostridium butyricum not only degrades enzymatic hydrolysates, but it is also a commonly used probiotic in aquatic feed. Therefore, the fermentation process not only breaks down the residue of houttuynia cordata into substances that are more easily absorbed by fish, but also promotes the reproduction of beneficial microorganisms, improves the intestinal health of fish, and enhances their resistance to pathogens.

[0070] To ensure that the Clostridium butyricum in the fermentation products is retained in the feed products, excessively high temperatures should be avoided throughout the entire process of processing the fermentation products into part of the feed.

[0071] Accordingly, in step S3, in addition to air drying, the mixed system after fermentation can also be dried using freeze-drying technology to accelerate the drying process until the moisture content of the mixed system after fermentation is below 10%. Freeze-drying can retain the active ingredients in the fermentation products to the greatest extent, such as metabolites produced by Clostridium butyricum and nutrients produced during fermentation, avoiding the loss of active ingredients caused by high-temperature drying.

[0072] Step S6 does not employ traditional conditioning; instead, the edible gel material is formulated into a binder solution. This binder solution is then mixed with the core-shell particles, and the mixture is molded to obtain aquatic feed using traditional Chinese medicine residue. A feed pelleting machine, especially a feed pellet mill with a die, is preferred. If a screw extruder is used, the die head temperature should be controlled below 65°C.

[0073] The structure of the obtained feed is as follows Figure 1 and Figure 2 As shown, each feed pellet contains multiple core-shell pellets 1, with gel 2 filling and binding the core-shell pellets 1 together. Each core-shell pellet 1 includes a core material 12 and a shell layer 11 covering the surface of the core material 12. The shell layer 11 is mainly composed of starch from yam residue. Flavonoids and polysaccharides in the fermentation products are easily lost in water. However, with the double barrier of the shell layer 11 and gel 2, the nutrients and disease-resistant active substances in the core material are less likely to be lost in the fishpond.

[0074] The edible gelling material is at least one of agar, gelatin, and gellan gum. Among them, agar and gellan gum are more effective in prolonging the time for the feed to dissolve in water. Specifically, the edible gelling material accounts for 3% to 8% of the aquatic feed using traditional Chinese medicine residue, and the mass of the edible gelling material is based on dry weight.

[0075] The specific steps of step S5 include:

[0076] S51: Steam the yam residue, then place it in an environment of 1℃~4℃ for more than 12 hours, crush it and sieve it, add 3 to 5 times the weight of water to make slurry, and add 2 to 5 parts of calcium stearate for every 100 parts of yam residue slurry.

[0077] S52: Spray the yam residue slurry onto the surface of the core material.

[0078] S53: Dry with air at 40℃~50℃ to obtain core-shell particles.

[0079] Currently, the extraction of medicinal components from yam is mostly done using organic solvents. After a single extraction, the yam residue still contains anti-nutritional factors such as calcium oxalate and yam alkaloids. Steaming (e.g., heating with steam at normal pressure for 8-15 minutes) removes a large number of these anti-nutritional factors. Then, partial retrogradation of the starch occurs in a low-temperature environment, facilitating subsequent pulverization and pulping. Pulverization and sieving remove coarse fibers from the yam residue. In step S51, adding 3-5 times the mass of water for pulping is based on the weight of the sieved particles.

[0080] Steps S52 to S53 can be carried out in a fluidized bed coating equipment, where the low-temperature hot air of the fluidized bed coating equipment is used to uniformly coat the starch slurry onto the surface of the core material and then dry it to form a shell.

[0081] Adding a small amount of calcium stearate to yam residue slurry can improve the stability and adhesion of the shell, and prolong the time the feed dissolves in water. At the same time, calcium stearate can supplement the feed with calcium, which helps in the development of fish bones and scales.

[0082] Specifically, the core-shell pellets consist of a core material and a shell layer covering the surface of the core material. The particle size of the core material formed by grinding is 0.1 mm to 0.6 mm, and the thickness of the shell layer is 4 μm to 80 μm. This size facilitates the binding of multiple core-shell pellets into a single feed pellet while also taking into account the starch content of the whole feed pellet. With a pulping water content of 3 to 5 times the mass of the sieved pellets, this shell layer thickness can be quickly dried and fixed in a fluidized bed apparatus.

[0083] The nutrients in step S4 can be from a conventional fish feed formula.

[0084] Preferably, the core material, by weight, comprises 20%–70% fishmeal, 20%–50% soybean meal, 3%–15% oil, 2%–20% immobilized fermented product, and 0.5%–2% dipotassium hydrogen phosphate. The oil can be fish oil, vegetable oil, etc. Dipotassium hydrogen phosphate neutralizes the acidity of the fermentation products, modifies their sour taste, improves feed palatability, and provides phosphorus and potassium. Phosphorus promotes cell metabolism, while potassium helps regulate osmotic pressure and growth and development, thus promoting skeletal development and improving the overall health of fish.

[0085] The aquatic feed using traditional Chinese medicine residue prepared in this application embodiment can be used as the main feed on its own. The aquatic feed using traditional Chinese medicine residue prepared in this application embodiment can also be used as a health-promoting feed mixed with conventional feed. For example, during the aquaculture process, pond samples are taken regularly, and the liver color and intestinal health are examined by opening the abdomen. The mixing ratio of the health-promoting feed to the conventional feed can be adjusted according to the health status of the fish. The mixing ratio of the health-promoting feed to the conventional feed can be adjusted within the range of 1:10 to 10:1.

[0086] Example 1

[0087] The residue of houttuynia cordata (provided by Guangdong Yifang Pharmaceutical Co., Ltd.) was crushed into particles with a diameter of 0.5mm~1mm. Phosphate buffer with pH of 5.0~6.0 was added until the residue was completely submerged. Cellulase (Shenzhen Lefu Biotechnology Co., Ltd.) was added and stirred at 35℃~40℃ for 4 hours. 1.5g of cellulase was added for every 100g of houttuynia cordata residue.

[0088] The enzymatic hydrolysate was subjected to steam distillation at a temperature of 90℃~95℃ for 2.5 hours to remove volatile components and obtain the residue.

[0089] Add the inoculum to the residue, maintain the pH at 4.5-5.5 with phosphate buffer, and ferment for 7 days in a closed environment at 30℃-35℃. The inoculum is Clostridium butyricum (Weifang Yihao Biotechnology Co., Ltd.), with 5g added per 1kg of phosphate buffer. Dry the fermented mixture until the moisture content is below 10% to obtain immobilized fermentation material.

[0090] The immobilized fermented material was mixed with nutrients and ground into powder to obtain a core material with a particle size distribution of 0.3 mm to 0.6 mm. The core material, by weight, consisted of 20% fish meal, 50% soybean meal, 15% fish oil, 14.2% immobilized fermented material, and 0.8% dipotassium hydrogen phosphate.

[0091] Steam the yam residue (provided by Guangdong Yifang Pharmaceutical Co., Ltd.), then place it in an environment of 1℃~4℃ for 12 hours, crush it and sieve it, add 5 times the weight of water to make a slurry, and add 3 parts of calcium stearate for every 100 parts of yam residue slurry.

[0092] Yam residue slurry is sprayed onto the surface of the core material and dried to obtain core-shell particles with a shell thickness of 0.05 mm to 0.075 mm.

[0093] Using shell-shell particles as raw material, after conditioning, they are shaped by a screw extruder to obtain the aquatic feed made from the traditional Chinese medicine residue in Example 1, which is adult fish feed with a diameter of about 3 mm and a length of about 5 mm.

[0094] Example 2

[0095] The residue of houttuynia cordata (provided by Guangdong Yifang Pharmaceutical Co., Ltd.) was crushed into particles with a diameter of 0.5mm~1mm. Phosphate buffer with pH of 5.0~6.0 was added until the residue was completely submerged. Cellulase (Shenzhen Lefu Biotechnology Co., Ltd.) was added and stirred at 35℃~40℃ for 5 hours. 1 gram of cellulase was added for every 100 grams of houttuynia cordata residue.

[0096] The enzymatic hydrolysate was subjected to steam distillation at a temperature of 90℃~95℃ for 2 hours to remove volatile components and obtain the residue.

[0097] The inoculum was added to the residue, and the pH was maintained at 4.5-5.5 with phosphate buffer. Fermentation was carried out for 7 days in a closed environment at 30℃-35℃. The inoculum was Clostridium butyricum (Weifang Yihao Biotechnology Co., Ltd.), with 5g added per 1kg of phosphate buffer. The fermented mixture was freeze-dried until the moisture content was below 10% to obtain immobilized fermentation material.

[0098] The immobilized fermentation material was mixed with nutrients and ground into powder to obtain a core material with a particle size distribution of 0.3 mm to 0.6 mm. The core material, by weight, consisted of 22% fish meal, 48.5% soybean meal, 13% fish oil, 15% immobilized fermentation material, and 1.5% dipotassium hydrogen phosphate.

[0099] Steam the yam residue (provided by Guangdong Yifang Pharmaceutical Co., Ltd.), then place it in an environment of 1℃~4℃ for 12 hours, crush it, sieve it, add 3 times the weight of water to make a slurry, and add 2 parts of calcium stearate for every 100 parts of yam residue slurry.

[0100] The yam residue slurry is sprayed onto the surface of the core material using a fluidized bed coating equipment.

[0101] Core-shell particles were obtained by air drying at 40℃~50℃ in a fluidized bed coating equipment, with a shell thickness of 0.05 mm to 0.075 mm.

[0102] Agar was prepared into a binder solution, with the weight of the agar solute being equivalent to 5% of the weight of the core-shell particles. The binder solution and core-shell particles were mixed and pressed using a feed molding machine to obtain the aquatic feed made from the Chinese herbal medicine residue in Example 2, which is adult fish feed with a short axis of about 3 mm and a long axis of about 5 mm.

[0103] Comparative Example 1

[0104] The residue of houttuynia cordata (provided by Guangdong Yifang Pharmaceutical Co., Ltd.) was pulverized into particles with a diameter of 0.5mm~1mm and mixed with corn flour, fish meal, soybean meal, fish oil, calcium stearate, and potassium dihydrogen phosphate. By weight, corn flour accounted for 29%, fish meal for 14%, soybean meal for 35%, fish oil for 10%, houttuynia cordata residue for 10.5%, potassium dihydrogen phosphate for 0.7%, and calcium stearate for 0.8%. After conditioning, the mixture was extruded using a screw extruder to obtain the adult fish feed of Comparative Example 1, with a diameter of approximately 3mm and a length of approximately 5mm.

[0105] To prepare general grass carp feed, mix 10 parts fish meal, 10 parts soybean meal, 40 parts wheat bran, 30 parts corn flour, 0.2 parts compound minerals, 0.2 parts compound vitamins, 0.1 parts butyric acid bacteria, and 9.5 parts fish oil by weight. After conditioning, you will get general grass carp feed, which is adult fish feed with a diameter of about 3 mm and a length of about 5 mm.

[0106] Maintain the water temperature in the rearing ponds at 20℃~28℃, pH= 6.5~7.5, and dissolved oxygen >5mg / L. Stock each of the four rearing ponds with 250 grass carp weighing 3 jin (1500±20g). Feed the fish twice a day, from 9:00 to 10:00 and from 15:00 to 16:00, with a daily feed amount of 5% of the grass carp's body weight.

[0107] Pond No. 1 was continuously fed with regular grass carp feed.

[0108] Pond No. 2 was fed a mixed feed on the first day, with the ratio of feed prepared in Example 1 to general grass carp feed being 1:9. On the second day, the same mixed feed was used, with a ratio of feed prepared in Example 1 to general grass carp feed being 2:8. On the third day, the same mixed feed was used, with a ratio of feed prepared in Example 1 to general grass carp feed being 3:7. On the fourth day, the same mixed feed was used, with a ratio of feed prepared in Example 1 to general grass carp feed being 4:6. On the fifth day, the same mixed feed was used, with a ratio of feed prepared in Example 1 to general grass carp feed being 5:5. On the sixth day, the same mixed feed was used, with a ratio of feed prepared in Example 1 to general grass carp feed being 6:4. On the seventh day, the same mixed feed was used, with a ratio of feed prepared in Example 1 to general grass carp feed being 7:3. This mixing ratio (feed prepared in Example 1: general grass carp feed = 7:3) was maintained daily thereafter.

[0109] Pond No. 3 was fed a mixed feed on the first day, with the ratio of feed prepared in Example 2 to general grass carp feed being 1:9. On the second day, the same mixed feed was used, with a ratio of feed prepared in Example 2 to general grass carp feed being 2:8. On the third day, the same mixed feed was used, with a ratio of feed prepared in Example 2 to general grass carp feed being 3:7. On the fourth day, the same mixed feed was used, with a ratio of feed prepared in Example 2 to general grass carp feed being 4:6. On the fifth day, the same mixed feed was used, with a ratio of feed prepared in Example 2 to general grass carp feed being 5:5. On the sixth day, the same mixed feed was used, with a ratio of feed prepared in Example 2 to general grass carp feed being 6:4. On the seventh day, the same mixed feed was used, with a ratio of feed prepared in Example 2 to general grass carp feed being 7:3. This mixing ratio (feed prepared in Example 2: general grass carp feed = 7:3) was maintained daily thereafter.

[0110] Pond No. 4 was fed a mixed feed on the first day, with a ratio of 1:9 (comparative ratio 1 feed: general grass carp feed). On the second day, the ratio was 2:8 (comparative ratio 1 feed: general grass carp feed). On the third day, the ratio was 3:7 (comparative ratio 1 feed: general grass carp feed). On the fourth day, the ratio was 4:6 (comparative ratio 1 feed: general grass carp feed). On the fifth day, the ratio was 5:5 (comparative ratio 1 feed: general grass carp feed). On the sixth day, the ratio was 6:4 (comparative ratio 1 feed: general grass carp feed). On the seventh day, the ratio was 7:3 (comparative ratio 1 feed: general grass carp feed). This mixing ratio (7:3 for comparative ratio 1 feed: general grass carp feed) was maintained daily thereafter.

[0111] After a total of 80 days of rearing, the weight gain rate and enteritis incidence rate of grass carp in each pond were tested. The test results are shown in Table 1 below.

[0112] Table 1

[0113] 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%

[0114] A comparison of Pond 4 and Pond 1 shows that adding Chinese herbal medicine residue can improve the grass carp's resistance to enteritis, but it will have a certain impact on feed palatability. For example, Pond 4 has the lowest incidence of enteritis, but the fish grow slowly, resulting in low economic benefits. The feed in Ponds 2 and 3, after being treated according to this application, has little impact on feed palatability, as evidenced by the weight gain rate and feeding time after daily feeding. Compared with Ponds 1 and 2, Pond 3 has an even lower incidence of enteritis and a greater weight gain rate, indicating that when fed only with ordinary grass carp feed, the fish are more susceptible to disease and fail to fully realize their growth potential. However, after using Chinese herbal medicine residue, the incidence of digestive diseases decreases, nutrient utilization is higher, and therefore weight gain is faster. Comparing Ponds 2 and 3, the incidence of enteritis is similar, but the weight gain rate is lower than that of Pond 3. This may be because the feed in Pond 3 allows more probiotics to survive in the fermentation products, which is more conducive to the fish's full absorption of nutrients during digestion. The incidence of enteritis in ponds No. 2 and No. 3 was higher than that in pond No. 4, possibly because some disease-fighting components were inevitably lost during the distillation and fermentation process. The project team will continue to study how to retain more active ingredients while reducing the impact on palatability.

[0115] In summary, this solution is expected to improve the disease resistance and growth performance of fish, providing a new option for green disease control in aquaculture.

[0116] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0117] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing aquatic feed using traditional Chinese medicine residue, characterized in that, Includes the following steps: The residue of Houttuynia cordata was enzymatically hydrolyzed with cellulase to obtain the hydrolysate; The enzymatic hydrolysate was subjected to steam distillation to remove volatile components, yielding a residue. Add microbial agents to the residue for fermentation, and dry the fermented mixture to obtain an immobilized ferment. The immobilized fermentation material is mixed with nutrients and ground into powder to obtain the core material; Prepare a yam residue slurry, coat the core material with the yam residue slurry, and dry to obtain core-shell particles; Using the core-shell particles as raw materials, the aquatic feed containing the Chinese herbal medicine residue is formed. The microbial agent includes Clostridium butyricum; The step of drying the fermented mixture includes: freeze-drying the fermented mixture until the moisture content is below 10%; The step of molding the aquatic feed using the core-shell particles as raw material to obtain the aquatic feed using the Chinese herbal medicine residue includes: preparing an edible gel material into an adhesive solution, mixing the adhesive solution and the core-shell particles, and molding to obtain the aquatic feed using the Chinese herbal medicine residue. The edible gelling material is at least one of agar, gelatin, and gellan gum.

2. The method for preparing aquatic feed using traditional Chinese medicine residue according to claim 1, characterized in that, The step of enzymatically hydrolyzing the residue of Houttuynia cordata with cellulase includes: The houttuynia cordata 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, and the cellulase is added. The mixture is stirred at 35°C to 40°C for 4 to 6 hours. The amount of cellulase added is equivalent to 1% to 2% of the mass of the houttuynia cordata residue.

3. The method for preparing aquatic feed using traditional Chinese medicine residue according to claim 1, characterized in that, The steam distillation is required to be performed at 90℃~95℃ for 2h~3h.

4. The method for preparing aquatic feed using traditional Chinese medicine residue according to claim 1, characterized in that, The fermentation requirements are: a closed environment at 30℃~35℃, pH maintained at 4.5~5.5 with phosphate buffer, and fermentation for 5~7 days.

5. The method for preparing aquatic feed using traditional Chinese medicine residue according to claim 1, characterized in that, The core material, by weight, comprises 20%–70% fishmeal, 20%–50% soybean meal, 3%–15% oil, 2%–20% immobilized fermented material, and 0.5%–2% dipotassium hydrogen phosphate; The core-shell particle includes a core material and a shell layer covering the surface of the core material, wherein the shell layer accounts for 20% to 40% of the mass of the core-shell particle; On a dry weight basis, the edible gel material accounts for 3% to 8% of the aquatic feed containing the Chinese herbal medicine residue used in the application.

6. The method for preparing aquatic feed using traditional Chinese medicine residue according to claim 1, characterized in that, The steps of preparing yam residue slurry, coating the core material surface with the yam residue slurry, and drying to obtain core-shell particles include: Steam the yam residue, then place it in an environment of 1℃~4℃ for more than 12 hours, crush it and sieve it, add 3 to 5 times the weight of water to make a slurry, and add 2 to 5 parts of calcium stearate for every 100 parts of the yam residue slurry. The yam residue slurry is sprayed and coated onto the surface of the core material; The core-shell particles were obtained by drying with air at 40℃~50℃.

7. An aquatic feed using traditional Chinese medicine residue, characterized in that, It is made from the aquatic feed preparation method using traditional Chinese medicine residue as described in any one of claims 1 to 6.

Images