Feed containing plant extract and preparation method thereof

Abstract

The invention relates to the technical field of feeds, in particular to a feed containing plant extracts and a preparation method thereof.The feed is prepared from, by weight, 0.5-1.5 parts of diatomite carrier loaded with the plant extracts and 70-100 parts of basic feed raw materials; wherein the basic feed comprises the following raw materials in parts by weight: 50-70 parts of corn, 17.5-25 parts of soybean meal, 1.2-2 parts of mountain flour, 0.8-1.5 parts of calcium hydrogen phosphate, 0.3-0.5 part of table salt and 0.2-1 part of a vitamin and mineral premix, and the plant extract is selected from at least one of tea tree oil, peppermint oil or cinnamon oil. The prepared modified diatomite powder can realize slow and continuous release of plant extracts such as tea tree oil in intestinal tracts, and is beneficial to improving the utilization efficiency and biological activity of the plant extracts such as tea tree oil.

Description

Technical Field

[0001] This invention relates to the field of feed technology, and in particular to a feed containing plant extracts and its preparation method. Background Technology

[0002] In the livestock and poultry farming industry, feed additives are a crucial component for improving farming efficiency. Antibiotics have long been used as feed additives to enhance animal production performance and feed utilization efficiency, contributing to the improvement of the farming industry's quality and efficiency. However, in actual livestock and poultry feed production and farming practices, the irrational addition and excessive use of antibiotics have become increasingly prominent, easily leading to excessive drug residues in livestock and poultry products and the proliferation and spread of antibiotic-resistant bacteria in the farming environment. Most countries have banned the use of antibiotic growth promoters in animals. Plant extracts, as a class of green active substances, are a general term for active ingredients obtained from various parts of plants, such as roots, stems, leaves, flowers, and fruits, through various separation and purification techniques, including physical, chemical, and biological methods. They possess significant physiological functions such as antibacterial, antioxidant, and enhancement of livestock and poultry immunity. Given their wide availability, high medicinal value, relatively low production cost, extremely low residue levels when applied to livestock and poultry feed, low likelihood of inducing bacterial resistance, and minimal side effects, plant extracts have become one of the ideal alternatives to antibiotic-based growth promoters in the livestock and poultry feed sector.

[0003] Patent publication number CN107691785A discloses a feed additive containing plant extracts, its preparation method, and its application. The feed additive comprises the following components by weight: 57-83 parts plant extracts, 3-5 parts microecological preparations, and 12-40 parts carrier. The preparation method involves first preparing all components, then sieving the plant extracts, adding the microecological preparations and carrier, and mixing thoroughly. The plant extracts and microecological preparations in this feed additive work synergistically to effectively regulate the balance of intestinal flora in animals, improve feed palatability and utilization, and enhance the body's antioxidant capacity and immune function.

[0004] However, conventional porous carriers rely on physical adsorption to load plant essential oils, resulting in weak binding forces and easy desorption loss during processing and storage, as well as limited loading capacity. Secondly, unprotected extracts are easily and rapidly absorbed or degraded in the animal's stomach and upper digestive tract, making it difficult to accurately reach the target site and leading to low bioavailability. Plant essential oils are heat-sensitive and highly volatile, easily volatilizing, oxidizing, or thermally decomposing during high-temperature conditioning and high-pressure pelleting of feed, causing significant loss or even inactivation of the active ingredients in the product. Furthermore, directly adding oily extracts can easily cause feed clumping and uneven mixing, resulting in excessively high local concentrations affecting palatability or excessively low concentrations rendering them ineffective, with poor uniformity and controllability. Summary of the Invention

[0005] To address the problems mentioned in the background section, the present invention provides a feed containing plant extracts and a method for preparing the same.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a feed containing plant extracts includes the following steps: S1. Add the activated diatomaceous earth to the aqueous phase, then add N-vinylformamide and stir for 10-30 minutes at a stirring speed of 200-300 rpm. Add a mixed solution containing bismaleimide and polyethylene glycol diacrylate, add an initiator, and stir the reaction while controlling the temperature. After the reaction is completed, wash with acid, separate and dry to obtain modified diatomaceous earth powder. S2. The modified diatomaceous earth powder is mixed with plant extracts and impregnated. After separation, a diatomaceous earth carrier loaded with plant extracts is obtained. S3. Add the diatomaceous earth carrier loaded with plant extracts and the basic feed ingredients to a mixer and mix at 150-250 rpm for 20-40 minutes. Then, introduce steam for conditioning treatment to obtain the conditioned material. Send the conditioned material to a pellet mill for pressing and molding. The die diameter of the pellet mill is 2-8 mm and the die speed is 100-200 rpm. Cool to room temperature to obtain feed containing plant extracts.

[0007] Further, in step S1, the mass ratio of diatomaceous earth to N-vinylformamide is 1:(1.5-2.5), the amount of water added is 1.5-3 times the mass of diatomaceous earth, and the initiator is selected from at least one of azobisisobutyronitrile, potassium persulfate, or sodium persulfate, and its amount is 0.5-1.5% of the total mass of N-vinylformamide and bismaleimide. Specifically, when the initiator is azobisisobutyronitrile, its amount is preferably 0.8-1.2%; when the initiator is potassium persulfate or sodium persulfate, its amount is preferably 0.5-1.0%, and the potassium persulfate or sodium persulfate needs to be prepared into an aqueous solution with a mass concentration of 5-10% using deionized water before use.

[0008] Further, the activation treatment in step S1 specifically involves placing diatomaceous earth in a muffle furnace and activating it at a high temperature of 500-800℃ for 1-3 hours. After cooling to room temperature, it is then pulverized through a 100-200 mesh sieve. The mixed solution is prepared by stirring bismaleimide and polyethylene glycol diacrylate at room temperature for 5-10 minutes at a stirring speed of 150-250 rpm. The drying temperature is 80-105℃, and the drying time is 2-4 hours. After drying, it is pulverized through an 80-120 mesh sieve.

[0009] Furthermore, the conditions for controlling the temperature and stirring reaction in step S1 include: a reaction temperature of 60-85℃, a reaction time of 2-6h, and a stirring speed of 300-600rpm.

[0010] Further, in step S1, the mass ratio of bismaleimide to polyethylene glycol diacrylate in the mixed solution is 1:(0.5-2). Acid washing is performed using a 5-15% hydrochloric acid or sulfuric acid solution at 40-60°C for 1-3 washes. The solid-liquid ratio during acid washing is 1:5-1:10 (g / mL), with intermittent stirring every 30 minutes for 5 minutes at a stirring speed of 100-150 rpm. After acid washing, the solution is washed with deionized water until the pH of the washing solution reaches 6.5-7.5, followed by separation.

[0011] Further, in step S2, the plant extract is selected from at least one of tea tree oil, peppermint oil or cinnamon oil, wherein the purity of the plant extract is ≥95%, and the mass ratio of modified diatomaceous earth powder to plant extract is 1:(0.3-0.6).

[0012] Further, the impregnation treatment in step S2 is as follows: after mixing the modified diatomaceous earth powder with the plant extract, the mixture is placed in a vacuum container, and a vacuum of (-0.09)-(-0.10) MPa is applied at room temperature and maintained for 25-35 min. Then the vacuum is released to atmospheric pressure and impregnation continues for 10-14 h.

[0013] Furthermore, in step S3, the basic feed ingredients include corn, soybean meal, limestone powder, dicalcium phosphate, salt, and a vitamin and mineral premix. The ratio of the diatomaceous earth carrier loaded with plant extracts to the basic feed ingredients is 1:(80-150). All basic feed ingredients are pulverized through an 80-100 mesh sieve before use. The moisture content of the pulverized corn is controlled at 10-12%, and the crude protein content of the pulverized soybean meal is ≥40%. The vitamin and mineral premix contains conventional components such as vitamin A, vitamin D3, vitamin E, iron, zinc, manganese, and selenium, and the content of each component meets the feeding standards for livestock, poultry, or aquatic animals.

[0014] Further, the conditioning process in step S3 specifically involves: introducing saturated steam at a pressure of 0.1-0.3 MPa into the mixture in a mixer to raise the material temperature to 75-85°C, and maintaining this temperature for 40-90 seconds. After conditioning, the moisture content of the material is controlled at 14-18%. The temperature of the saturated steam is 100-120°C, and the steam introduction rate is 0.5-1.0 L / min. During the conditioning process, continuous stirring is carried out at a stirring speed of 150-200 rpm.

[0015] According to another aspect of the present invention, a feed containing plant extracts prepared by the above-described method is provided, comprising, by weight, the following raw materials: 0.5-1.5 parts of a diatomaceous earth carrier loaded with plant extracts, and 70-100 parts of basic feed ingredients; wherein the basic feed ingredients include: 50-70 parts of corn, 17.5-25 parts of soybean meal, 1.2-2 parts of limestone powder, 0.8-1.5 parts of dicalcium phosphate, 0.3-0.5 parts of salt, and 0.2-1 parts of vitamin and mineral premix; the plant extracts are selected from at least one of tea tree oil, peppermint oil, or cinnamon oil. The feed has a particle size of 2-8 mm and a bulk density of 0.6-0.8 g / cm³. 3 The moisture content is 10-14%.

[0016] According to another aspect of the present invention, the above-mentioned feed is provided for use in the feeding of livestock, poultry, or aquatic animals to improve animal growth performance, improve intestinal health, and / or enhance immunity. The livestock include at least one of pigs, chickens, ducks, cattle, and sheep, and the aquatic animals include at least one of fish, shrimp, and crab. In application, the feed can be fed directly as a basal feed alone, or it can be mixed with other compound feeds at a mixing ratio of 1:(1-5) (by weight). The feeding amount for livestock is 2-5% of their body weight per day, and the feeding amount for aquatic animals is 1-3% of their body weight per day, divided into 2-3 feedings per day, with a feeding cycle of not less than 7 days.

[0017] The beneficial effects of this invention are: 1. The technical solution of this invention introduces monomers such as N-vinylformamide and bismaleimide, as well as polyethylene glycol diacrylate, into an aqueous dispersion system of diatomaceous earth, and copolymerizes and crosslinks under the action of an initiator. A stable polymer network rich in amide groups, imide rings, and ether bonds is formed on the surface of the diatomaceous earth and the inner walls of its porous channels. Through chemical bonding and physical entanglement, this network tightly binds to the diatomaceous earth framework, constructing an organic-inorganic hybrid hierarchical porous structure, forming a composite carrier with diatomaceous earth as the framework and the polymer network as the functional layer. The polymer layer is rich in various polar functional groups, enabling diverse intermolecular interactions with the active ingredients in plant extracts, thereby enhancing the carrier's affinity and binding strength to the extracts. In feed processing and storage, this provides more effective protection for heat-sensitive and volatile plant extracts, helping to reduce activity attenuation and loss caused by high temperatures, oxidation, and other factors.

[0018] 2. The polymer network in the carrier of this invention has certain hydrophilicity and environmental responsiveness. When it enters the animal digestive tract environment, the network can swell, thereby regulating the permeability of its internal pores and setting up a dynamic diffusion barrier for the release of plant extracts. This transforms the release kinetics from a rapid, explosive release to a more gradual, sustained release mode, which helps to prolong the action time of the active ingredients and allows them to be released more in the later part of the intestine, thereby enhancing their local regulatory potential on intestinal health and helping to improve their overall bioavailability.

[0019] 3. The loaded plant extracts exist in solid powder form, solving problems such as feed clumping, uneven mixing, and poor flowability caused by directly adding oily extracts. This solid carrier powder can achieve highly uniform mechanical mixing with basic feed ingredients such as corn and soybean meal, ensuring uniform distribution of active ingredients in the feed and avoiding the risk of excessively high local concentrations affecting palatability or excessively low concentrations leading to inactivation. Simultaneously, because the carrier effectively coats and protects the heat-sensitive extracts during processing, the loss of active ingredients is minimized during subsequent high-temperature and high-humidity processing steps such as steam conditioning and pelleting, ensuring stable efficacy of the final product. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the preparation process of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the following preparation examples and embodiments, diatomaceous earth (industrial grade, particle size D50 corresponding to ≤10% residue on a 150-mesh sieve) was purchased from Jilin Yuantong Mining Co., Ltd.; N-vinylformamide (CAS No.: 13162-05-5, purity ≥99%), bismaleimide (4,4'-bismaleimide diphenylmethane, CAS No.: 13676-54-5, purity ≥98%), polyethylene glycol diacrylate (Mn=700, CAS No.: 26570-48-9, purity ≥95%), and azobisisobutyronitrile (CAS No.: 78-67-1, purity ≥98%, chemically pure) were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; potassium persulfate (CAS No.: 7727-21-1, purity ≥99%, analytical grade) and sodium persulfate (CAS No.: 7775-27-1 (purity ≥99%, analytical grade), sodium dihydrogen phosphate (CAS No.: 7558-80-7, analytical grade), and disodium hydrogen phosphate (CAS No.: 7558-79-4, analytical grade) were purchased from Sinopharm Chemical Reagent Co., Ltd.; hydrochloric acid (CAS No.: 7647-01-0, 36-38%, analytical grade) and sulfuric acid (CAS No.: 7664-93-9, 95-98%, analytical grade) was purchased from Chengdu Kelong Chemical Co., Ltd.; tea tree oil (naturally extracted, purity ≥96%, food grade) was purchased from Jiangxi Ji'an Tianyu Natural Plant Essential Oil Factory; corn (feed grade, crushed through a 90-mesh sieve, moisture ≤13%), soybean meal (feed grade, crushed through a 90-mesh sieve, crude protein ≥42%), limestone powder (feed grade calcium carbonate), dicalcium phosphate (feed grade, anhydrous), sodium chloride (feed grade), and vitamin and mineral premix (1% laying hen compound premix) were all purchased from New Hope Liuhe Co., Ltd.

[0023] In addition, the supporting materials used for experiments and tests, namely pepsin (derived from porcine gastric mucosa, enzyme activity ≥250 U / mg, CAS No.: 9001-75-6), pancreatin (derived from porcine pancreas, CAS No.: 8049-47-6), and porcine bile salts (CAS No.: 8008-63-7), were purchased from Beijing Solarbio Science & Technology Co., Ltd. Example 1

[0024] A method for preparing a feed containing plant extracts includes the following steps: S1. Diatomaceous earth was placed in a muffle furnace and activated at 650℃ for 2 hours. After cooling to room temperature, it was pulverized and passed through a 150-mesh sieve to obtain activated diatomaceous earth. 100g of the activated diatomaceous earth was added to 200g of aqueous phase, followed by 200g of N-vinylformamide. The mixture was stirred for 20 minutes at 250rpm. A mixed solution containing 50g of bismaleimide and 50g of polyethylene glycol diacrylate was added. This mixed solution was prepared by stirring the two together at room temperature for 8 minutes at 200rpm. 3g of azobisisobutyronitrile (AIBN) initiator was added, and the reaction was carried out at 75℃ and 450rpm for 4 hours. After the reaction was completed, a 10% hydrochloric acid solution with a solid-liquid ratio of 1:8 g / mL was used to wash the diatomaceous earth at 50°C for 2 hours. During the washing process, the mixture was stirred intermittently for 5 minutes every 30 minutes at a stirring speed of 120 rpm. After acid washing, the mixture was washed with deionized water until the pH of the washing solution was 7.0. The mixture was then centrifuged and dried at 90°C for 3 hours. After drying, the mixture was pulverized and passed through a 100-mesh sieve to obtain modified diatomaceous earth powder.

[0025] S2. Mix 100g of modified diatomaceous earth powder with 45g of tea tree oil with a purity of 96%. Place the mixture in a vacuum container and apply a vacuum of -0.095MPa at room temperature (23℃) for 30min. Then release the vacuum to normal pressure and continue impregnation for 12h. After centrifugation, obtain the diatomaceous earth carrier loaded with plant extracts.

[0026] S3. 1.0 part of diatomaceous earth carrier loaded with plant extracts and 84 parts of basic feed ingredients (60 parts corn, 20 parts soybean meal, 1.5 parts limestone powder, 1 part dicalcium phosphate, 0.5 parts salt, and 1.0 part vitamin and mineral premix; all basic feed ingredients were pulverized through a 90-mesh sieve before use, with the moisture content of the corn controlled at 11% and the crude protein content of the soybean meal at 42%) added to a mixer and mixed at 200 rpm for 30 minutes. In the mixer, saturated steam at a pressure of 0.2 MPa and a temperature of 110°C was introduced into the mixture at a steam introduction rate of 0.7 L / min, raising the material temperature to 80°C and maintaining this temperature for 60 seconds. The conditioned material was then fed into a pellet mill for pressing and molding. The pellet mill had a die aperture of 5 mm and a die speed of 150 rpm. After cooling to room temperature, the feed containing plant extracts was obtained. Example 2

[0027] This embodiment is basically the same as Embodiment 1, with the main difference being: In S1, the diatomaceous earth activation conditions are: high-temperature activation at 500℃ for 1 hour, followed by pulverization through a 100-mesh sieve; 100g of activated diatomaceous earth is added to 150g of aqueous phase, along with 150g of N-vinylformamide, and stirred for 10 minutes at a stirring speed of 200rpm; the mixed solution consists of 50g of bismaleimide and 25g of polyethylene glycol diacrylate, stirred at room temperature for 5 minutes at a stirring speed of 150rpm; the initiator is replaced with 0.75g of potassium persulfate (prepared as a 5% aqueous solution with deionized water), the reaction temperature is 60℃, the stirring speed is 300rpm, and the reaction time is 2 hours; acid washing uses a 5% sulfuric acid solution with a solid-liquid ratio of 1:5g / mL, washing at 40℃ for 1 hour at a stirring speed of 100rpm, and washing until pH=6.5 after acid washing; drying temperature is 80℃, time is 2 hours, and pulverization through an 80-mesh sieve is performed.

[0028] In S2, the plant extract was replaced with 30g of 95% pure tea tree oil; the impregnation conditions were room temperature 20℃, vacuum degree -0.09MPa, maintained for 25min, and after releasing the vacuum, impregnation continued for 10h.

[0029] In S3, the loading carrier is 0.5 parts, and the basic feed ingredients are 70 parts (corn 50 parts, soybean meal 17.5 parts, limestone powder 1.2 parts, dicalcium phosphate 0.8 parts, salt 0.3 parts, and vitamin and mineral premix 0.2 parts); the mixing speed is 150 rpm and the time is 20 min; the saturated steam pressure is 0.1 MPa, the temperature is 100℃, the feed rate is 0.5 L / min, the material temperature is 75℃ and held for 40 s; the pellet mill die diameter is 2 mm and the rotation speed is 100 rpm. Example 3

[0030] This embodiment is basically the same as Embodiment 1, with the main difference being: In S1, the diatomaceous earth activation conditions are: high-temperature activation at 800℃ for 3 hours, followed by pulverization through a 200-mesh sieve; 100g of activated diatomaceous earth is added to 300g of aqueous phase, along with 250g of N-vinylformamide, and stirred for 30 minutes at a stirring speed of 300rpm; the mixed solution consists of 50g of bismaleimide and 100g of polyethylene glycol diacrylate, stirred at room temperature for 10 minutes at a stirring speed of 250rpm; the initiator is replaced with 3.0g of sodium persulfate (prepared as a 10% aqueous solution with deionized water), and the reaction temperature is 85℃, the stirring speed is 600rpm, and the reaction time is 6 hours; acid washing uses a 15% hydrochloric acid solution with a solid-liquid ratio of 1:10g / mL, washing at 60℃ for 3 hours at a stirring speed of 150rpm, and washing until pH=7.5 after acid washing; drying temperature is 105℃, time is 4 hours, and pulverization is followed by pulverization through a 120-mesh sieve.

[0031] In S2, the plant extract was replaced with 60g of 98% pure tea tree oil; the impregnation conditions were room temperature 25℃, vacuum degree -0.10MPa, maintained for 35min, and after releasing the vacuum, impregnation continued for 14h.

[0032] In S3, the loading carrier is 1.5 parts, and the basic feed ingredients are 100 parts (70 parts corn, 25 parts soybean meal, 2 parts limestone powder, 1.5 parts dicalcium phosphate, 0.5 parts salt, and 1 part vitamin and mineral premix); the mixing speed is 250 rpm and the time is 40 min; the saturated steam pressure is 0.3 MPa, the temperature is 120℃, the feed rate is 1.0 L / min, the material temperature is 85℃ and held for 90 s; the pellet mill die diameter is 8 mm and the rotation speed is 200 rpm.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: In S1, N-vinylformamide, bismaleimide, polyethylene glycol diacrylate and initiator are not added. Instead, 100g of activated diatomaceous earth is used directly as a carrier under the same conditions, and the remaining steps are exactly the same as in Example 1.

[0034] Comparative Example 2 The difference between this comparative example and Example 2 is as follows: In S1, the mixed solution containing bismaleimide and polyethylene glycol diacrylate is not added; only 200g of N-vinylformamide is added, and the amount of initiator azobisisobutyronitrile is 1.5% (i.e., 3g) of the mass of N-vinylformamide. The steps are exactly the same as in Example 1.

[0035] Comparative Example 3 The difference between this comparative example and Example 3 is as follows: 100g of commercially available corn cob powder (passed through a 100-mesh sieve) was used directly to replace the modified diatomaceous earth powder prepared in Example 1. In step S2, the corn cob powder was mixed with 45g of tea tree oil with a purity of 96%. Step S3 was exactly the same as in Example 3.

[0036] Based on the examples and comparative examples, six experimental groups were set up. EG1, EG2, and EG3 corresponded to Examples 1-3, respectively, and CG1, CG2, and CG3 corresponded to Comparative Examples 1-3, respectively. Pepsin (enzyme activity ≥250 U / mg), trypsin (derived from porcine pancreas), porcine bile salts, hydrochloric acid (analytical grade, used to prepare 0.1 M solution), sodium hydroxide (analytical grade, used to prepare 0.1 M solution), sodium dihydrogen phosphate, and disodium hydrogen phosphate (analytical grade, used to prepare 0.1 M phosphate buffer) were prepared. The experimental materials were 50 g of each of the six feed samples: EG1, EG2, EG3, CG1, CG2, and CG3.

[0037] The pH was adjusted to 2.0 with 0.1M hydrochloric acid solution. Pepsin was then dissolved in this pH 2.0 hydrochloric acid solution to prepare a pepsin solution with a concentration of 3.2 mg / mL. This solution was prepared fresh for each use to obtain simulated gastric juice. Separately, 0.1M phosphate-buffered saline (PBS) was prepared, and the pH of the PBS was adjusted to 6.8 with 0.1M sodium hydroxide solution. Pancreatin and porcine bile salts were then dissolved in this pH 6.8 PBS to prepare a solution with a pancreatin concentration of 10 mg / mL and a porcine bile salt concentration of 3 mg / mL. This solution was prepared fresh for each use to obtain simulated intestinal juice.

[0038] The six groups of feed samples were ground separately using a mortar and pestle, passed through an 80-mesh sieve, and thoroughly mixed. Based on the theoretical loading of tea tree oil in each group of samples, the powder was calculated and weighed (ensuring that the initial total amount of tea tree oil was consistent across all parallel experiments), and placed in 50 mL capped centrifuge tubes. Three parallel experiments were conducted for each group of samples.

[0039] Preheat the constant temperature water bath shaker to 37℃ and set the shaking speed to 100 rpm. Accurately add 20.0 mL of simulated gastric fluid preheated to 37℃ to each centrifuge tube and immediately seal it. Quickly place all centrifuge tubes in the 37℃ constant temperature water bath shaker, start timing, and shake for incubation. Take samples at 0.5h, 1h, and 2h after the start of incubation. At each time point, remove the corresponding centrifuge tube and immediately place it in a boiling water bath for 5 min to terminate the enzyme reaction. After cooling to room temperature, centrifuge at 4000 rpm for 10 min. Aspirate the supernatant with a syringe, filter it through a 0.45 μm microporous membrane, collect the filtrate in a clean sample tube, and store it temporarily at 4℃ or immediately determine the tea tree oil content. For samples that need to enter the intestinal fluid stage, after 2h sampling and processing, discard all supernatant and retain the solid residue at the bottom of the tube.

[0040] Accurately add 20.0 mL of preheated 37°C simulated intestinal fluid to a centrifuge tube containing the gastric juice residue. Seal tightly and return to a 37°C constant-temperature water bath shaker, continuing incubation at 100 rpm. Samples are taken at 1 h, 2 h, and 4 h after the start of intestinal fluid incubation (i.e., 3, 4, and 6 h after the start of the entire digestion experiment). The procedure is the same as for the gastric juice stage. The reaction is terminated by heating in a boiling water bath for 5 min. After cooling, centrifuge at 4000 rpm for 10 min, filter the supernatant, collect the filtrate, and store at 4°C or analyze immediately.

[0041] The concentration C of tea tree oil in the filtrate taken at each time point was directly determined by high performance liquid chromatography (HPLC). t (Unit: µg / mL), then the release amount represented by a single sample at this time point is: m t =C t ×V 消化液 Record the tea tree oil content in the filtrate of each sample at each time point. Calculate the cumulative release rate (t) using the following formula:

[0042] Among them, M t M0 represents the total mass of tea tree oil released into the simulated digestive fluid (gastric or intestinal fluid) from the start of the experiment to time t; M0 represents the initial total mass of tea tree oil loaded in the sample participating in the digestion experiment.

[0043] The results are shown in Table 1-2: Table 1. Cumulative release rate (%) of tea tree oil in simulated gastric juice in different feed samples

[0044]

[0045] Table 2. Cumulative release rate (%) of tea tree oil in simulated intestinal fluid of different feed samples

[0046] Note: The times in the table are intestinal fluid incubation times. The corresponding total digestion time (gastric fluid 2h + intestinal fluid time) is marked in parentheses.

[0047] As shown in Tables 1 and 2, after 2 hours of incubation in gastric juice, the cumulative release rates of tea tree oil in the example groups (EG1-EG3) were 22.1±0.8%, 28.5±1.0%, and 18.3±0.7%, respectively. These release rates were lower than those in the comparative group. The modified diatomaceous earth powder prepared in the examples provided good encapsulation and protection for the tea tree oil. Under the acidic environment of gastric juice (pH=2.0) and the action of pepsin, the modified diatomaceous earth structure remained relatively stable, making it difficult for the tea tree oil to be released from the carrier. The N-vinylformamide, bismaleimide, and polyethylene glycol diacrylate added during the modification process reacted under the action of the initiator, forming a network structure with certain spatial structure and chemical stability, encapsulating the tea tree oil and making it less susceptible to enzymatic hydrolysis and release in gastric juice.

[0048] After entering the intestinal fluid stage, the cumulative release rate of tea tree oil continued to increase. At the end of the experiment (4 hours of intestinal fluid incubation, total digestion time 6 hours), the cumulative release rates of EG1, EG2, and EG3 reached 76.5±1.8%, 81.2±2.0%, and 72.8±1.7%, respectively. The pH value (pH=6.8) and the components such as pancreatic enzymes and porcine bile salts in the intestinal fluid differed from those in gastric fluid. Various enzymes in the pancreatic fluid (such as lipase and protease) and porcine bile salts could destroy the structure of the modified diatomaceous earth, causing it to gradually decompose and release the encapsulated tea tree oil. Simultaneously, with the extension of digestion time, the structure of the modified diatomaceous earth was further destroyed, and the release amount of tea tree oil continuously increased. Differences in raw material ratios and process conditions in different embodiments led to variations in the structure and properties of the modified diatomaceous earth, thus affecting the release rate and final cumulative release rate of tea tree oil in the intestinal fluid.

[0049] In the comparative group CG1, the cumulative release rate of tea tree oil was 42.6±1.5% after 2 hours in gastric juice and 73.9±1.9% after 6 hours in intestinal juice. Compared with the example group, the release rate was higher in the gastric juice stage and relatively lower in the intestinal juice stage, with no significant increase in release in the later stages. Since N-vinylformamide, bismaleimide, polyethylene glycol diacrylate, and initiators were not added, the diatomaceous earth was not modified, resulting in a relatively loose structure and weak encapsulation effect on tea tree oil. Under the acidic environment and enzymatic action of gastric juice, tea tree oil is easily released from the diatomaceous earth, leading to a higher release rate in the gastric juice stage. After entering the intestinal juice, although pancreatic enzymes and porcine bile salts can also have a certain destructive effect on the structure of diatomaceous earth, due to the simple structure of diatomaceous earth itself, the initial release is relatively large, while the amount of tea tree oil that can be released in the later stages is relatively reduced, so the increase in the cumulative release rate is not significant.

[0050] The comparative group CG2 showed a cumulative release rate of 36.2±1.3% in gastric fluid after 2 hours and 71.5±1.8% in intestinal fluid after 6 hours, with release characteristics between CG1 and the example group. Only N-vinylformamide and an initiator were added, resulting in less complete modification of the diatomaceous earth compared to the example group. The formed structure somewhat enhanced the encapsulation effect of tea tree oil, but it was not as perfect as in the example group. In gastric fluid, some tea tree oil could still be released relatively easily, but the release rate was slower than that of CG1. After entering the intestinal fluid, the destructive effect of pancreatic enzymes and porcine bile salts on the diatomaceous earth structure allowed for continued release of tea tree oil, but due to incomplete modification, the release rate and final cumulative release rate also fell between CG1 and the example group.

[0051] In the comparative group, the cumulative release rate of CG3 in gastric juice was as high as 67.8±2.2% after 2 hours and in intestinal juice after 6 hours, reaching 78.3±2.3%. Release was extremely rapid in the gastric juice stage, while the increase in release in the intestinal juice stage was relatively small. Corn cob powder has a different structure than modified diatomaceous earth, resulting in poor encapsulation ability for tea tree oil. Under the acidic environment and enzymatic action of gastric juice, tea tree oil can be released from corn cob powder almost rapidly, leading to an extremely high release rate in the gastric juice stage. After entering the intestinal juice, although pancreatic enzymes and porcine bile salts can also have some effect on corn cob powder, the amount of tea tree oil already released in the early stages is limited, resulting in a relatively small increase in the cumulative release rate.

[0052] In summary, the modified diatomaceous earth powder prepared in the example group can effectively control the release rate of plant extracts such as tea tree oil in gastric and intestinal fluids, achieving slow and continuous release of plant extracts such as tea tree oil in the intestines, which is beneficial to improving the utilization efficiency and bioactivity of plant extracts such as tea tree oil.

[0053] In the description of this specification, the reference to terms such as "embodiment," "various embodiments," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or preparation example is included in at least one embodiment of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a feed containing a plant extract, characterized in that, Includes the following steps: S1. Add activated diatomaceous earth to the aqueous phase, then add N-vinylformamide and stir evenly. Add a mixed solution containing bismaleimide and polyethylene glycol diacrylate, add an initiator, control the temperature and stir the reaction. After the reaction is completed, wash with acid, separate and dry to obtain modified diatomaceous earth powder. S2. The modified diatomaceous earth powder is mixed with plant extracts and impregnated. After separation, a diatomaceous earth carrier loaded with plant extracts is obtained. S3. Add the diatomaceous earth carrier loaded with plant extracts and the basic feed ingredients to a mixer and mix them. Then, introduce steam for conditioning treatment to obtain the conditioned material. Send the conditioned material to a pellet mill for pressing and cooling to obtain feed containing plant extracts.

2. The production method according to claim 1, characterized by, In step S1, the mass ratio of diatomaceous earth to N-vinylformamide is 1:(1.5-2.5), the amount of water added is 1.5-3 times the mass of diatomaceous earth, and the initiator is selected from at least one of azobisisobutyronitrile, potassium persulfate or sodium persulfate, and its amount is 0.5-1.5% of the total mass of N-vinylformamide and bismaleimide.

3. The production method according to claim 1, characterized by, The conditions for controlling the temperature and stirring reaction in step S1 include: reaction temperature of 60-85℃, reaction time of 2-6h, and stirring speed of 300-600rpm.

4. The method of claim 1, wherein, In step S1, the mass ratio of bismaleimide to polyethylene glycol diacrylate in the mixed solution is 1:(0.5-2). The pickling is performed using a 5-15% hydrochloric acid or sulfuric acid solution at 40-60°C for 1-3 hours.

5. The preparation method according to claim 1, characterized in that, In step S2, the plant extract is selected from at least one of tea tree oil, peppermint oil or cinnamon oil, wherein the purity of the plant extract is ≥95%, and the mass ratio of modified diatomaceous earth powder to plant extract is 1:(0.3-0.6).

6. The method of claim 1, wherein, The impregnation process in step S2 is as follows: after mixing the modified diatomaceous earth powder with the plant extract, the mixture is placed in a vacuum container and a vacuum of (-0.09)-(-0.10) MPa is applied at room temperature and maintained for 25-35 minutes. Then the vacuum is released to atmospheric pressure and impregnation continues for 10-14 hours.

7. The preparation method according to claim 1, characterized in that, In step S3, the basic feed ingredients include corn, soybean meal, limestone powder, dicalcium phosphate, salt, and vitamin and mineral premix. The ratio of diatomaceous earth carrier loaded with plant extracts to the basic feed ingredients is 1:(80-150).

8. The preparation method according to claim 1, characterized in that, The conditioning process in step S3 is as follows: In the mixer, saturated steam with a pressure of 0.1-0.3 MPa is introduced into the mixture to make the material temperature reach 75-85℃, and it is maintained at this temperature for 40-90s. After conditioning, the moisture content of the material is controlled at 14-18%.

9. A feed containing plant extracts prepared by the method according to any one of claims 1-8, characterized in that, By weight, it includes the following ingredients: The mixture contains 0.5-1.5 parts of diatomaceous earth carrier loaded with plant extracts and 70-100 parts of basic feed ingredients. The basic feed ingredients include: 50-70 parts of corn, 17.5-25 parts of soybean meal, 1.2-2 parts of limestone powder, 0.8-1.5 parts of dicalcium phosphate, 0.3-0.5 parts of salt, and 0.2-1 parts of vitamin and mineral premix. The plant extracts are selected from at least one of tea tree oil, peppermint oil, or cinnamon oil.

10. The application of a feed containing plant extracts as described in claim 9 in the feeding of livestock, poultry, or aquatic animals, characterized in that, Used to improve animal growth performance, improve gut health and / or enhance immunity, wherein livestock and poultry include at least one of pigs, chickens, ducks, cattle and sheep, and aquatic animals include at least one of fish, shrimp and crab.

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