A feed for improving the intestinal health of livestock through rosemary oil and a method of preparing the same

Abstract

The present application relates to the field of livestock feed, and provides a feed for improving the intestinal health of livestock by rosemary oil and a preparation method thereof; the feed is composed of cyclodextrin-coated rosemary oil compound, corn flour, straw pellets, wheat, barley, rapeseed meal, cottonseed meal, peas, bran, bone meal, calcium carbonate, calcium hydrogen phosphate and the like. The cyclodextrin-coated rosemary oil compound is obtained by co-precipitation of rosemary essential oil nano-composite emulsion and cyclodextrin, and the rosemary essential oil nano-composite emulsion is mainly obtained by nano-emulsification of rosemary, alpha-tocopherol and chitosan; the above technologies significantly enhance the stability, slow-release performance and absorption rate of rosemary oil in the feed. The feed is uniformly mixed and granulated by a double-shaft paddle mixer, and the feed not only improves the intestinal health of livestock and enhances the nutrient absorption efficiency, but also has good processability, storage stability and long-term performance.

Description

Technical Field

[0001] This invention relates to the field of livestock feed technology, specifically to a feed that improves the intestinal health of livestock through rosemary oil and its preparation method. Background Technology

[0002] In modern animal husbandry, gut health plays a crucial role in livestock growth, immunity, and feed conversion rate. With the promotion of intensive farming models, gut health issues in livestock have become increasingly prominent, especially in high-density environments where the incidence of intestinal diseases has significantly increased, severely impacting production efficiency. Therefore, introducing functional additives into feed formulations to improve animal gut health has become a focus of industry attention. Rosemary oil, as a natural plant extract, exhibits the potential to improve gut microbiota balance and enhance intestinal barrier function due to its rich antioxidant and antibacterial components. For this application, rosemary oil added to feed must possess high bioactivity, good stability, and an appropriate release rate to ensure its sustained effectiveness in the animal's gut. Simultaneously, the material should have good environmental adaptability, maintaining the activity of its active ingredients during feed processing and storage, and being fully absorbed and utilized by the animal. The successful application of rosemary oil in feed can not only significantly improve livestock gut health and reduce disease incidence, thereby increasing farming efficiency, but also reduce antibiotic use and promote the development of green farming. Therefore, developing a feed based on rosemary essential oil additives not only has important application value, but can also provide strong support for the sustainable development of modern animal husbandry.

[0003] Currently, while rosemary essential oil additives have made some progress in improving the gut health of livestock, many shortcomings remain. For example, Chinese patent CN106578530A discloses a plant essential oil-based compound premixed feed for weaned pigs and its preparation method, but this method is insufficient in terms of component stability and bioactivity retention. The active ingredients in rosemary oil are easily oxidized or degraded during feed processing and storage, significantly reducing their effectiveness in animals. Furthermore, existing rosemary oil additives have low absorption and utilization rates in animals; some components may lose their activity due to enzymatic hydrolysis as they pass through the gastrointestinal tract, failing to fully exert their intended effects. Performance requirements mainly focus on two aspects: first, how to ensure the long-term stability of the essential oil in feed, avoiding the loss of active ingredients during storage and use; and second, how to improve its absorption efficiency in the livestock gut, ensuring that its effective components are fully utilized. The shortcomings of existing technologies mainly stem from insufficient research on the stability of essential oils under different environmental conditions, and a lack of systematic optimization of its release and absorption mechanisms in animals. These problems limit the widespread use of plant essential oils as feed additives and urgently require further technological innovation to solve. Summary of the Invention

[0004] (1) Technical problems to be solved The purpose of this invention is to provide a feed that improves the intestinal health of livestock through rosemary oil and its preparation method, thereby solving the problems of insufficient stability, slow-release performance and absorption rate of rosemary oil in feed.

[0005] (2) Technical solution To achieve the above objectives, the present invention provides the following technical solution: A feed for improving the intestinal health of livestock through rosemary oil, the feed comprising the following components in parts by weight: 0.5-2.0 parts of cyclodextrin-coated rosemary oil complex, 35.0-45.0 parts of corn flour, 15.0-25.0 parts of straw kernels, 10.0-20.0 parts of wheat, 5.0-10.0 parts of barley, 5.0-10.0 parts of rapeseed meal, 5.0-10.0 parts of cottonseed meal, 1.0-10.0 parts of peas, 10.0-15.0 parts of wheat bran, 1.5-2.0 parts of bone meal, 1.0-2.0 parts of calcium carbonate, 1.0-2.0 parts of dicalcium phosphate, 0.3-1.5 parts of salt, 2.0-5.0 parts of vegetable oil, 5.0-10.0 parts of alfalfa hay, and 5.0-10.0 parts of beet pulp; The raw materials for the cyclodextrin-coated rosemary oil complex include a rosemary essential oil nanocomposite emulsion and β-cyclodextrin in a mass ratio of 20-30:20-45; the cyclodextrin-coated rosemary oil complex is prepared by a co-precipitation method. The rosemary essential oil nanocomposite emulsion is prepared from the following raw materials in parts by weight: 30-40 parts rosemary essential oil, 3-8 parts α-tocopherol, 3-8 parts chitosan, 15-32 parts Tween 40 and 500 parts deionized water.

[0006] This invention utilizes cyclodextrin-coated rosemary oil complexes primarily to enhance the stability, sustained-release properties, anti-volatility, and reduce the irritation of rosemary oil in feed. Rosemary oil, due to its natural antioxidant and antibacterial properties, has the potential to improve animal gut health in livestock feed; however, its high volatility, easy oxidation, and certain irritation limit its widespread application in feed. This invention, by preparing rosemary oil into a nanoemulsion and further coating it with β-cyclodextrin, successfully overcomes the volatility and stability issues of rosemary oil during feed processing and storage, while significantly reducing the potential irritation of rosemary oil to animals.

[0007] The rosemary essential oil nanocomposite emulsion of this invention incorporates α-tocopherol and chitosan, which work synergistically. α-Tocopherol, a powerful antioxidant, effectively inhibits the oxidative degradation of active components in rosemary essential oil (such as rosmarinic acid and caryopsisic acid) caused by oxygen, light, or high temperature, thereby extending the emulsion's storage stability. Chitosan, a natural cationic polysaccharide, enhances the electrostatic repulsion between emulsion particles by forming a stable protective film on the emulsion surface, preventing droplet aggregation or sedimentation, while also improving the emulsion's sustained-release properties and environmental stability. The combined use of these two ingredients not only protects the chemical activity of rosemary essential oil but also significantly enhances the physical stability and functionality of the nanocomposite emulsion.

[0008] Furthermore, the rosemary essential oil in the cyclodextrin-encapsulated rosemary oil complex is in a nanoemulsion state. This encapsulation and nanoemulsification technologies not only effectively improve the stability of rosemary oil but also achieve its sustained-release function, prolonging the release time of rosemary oil in the animal's digestive tract and improving its bioavailability. This design ensures the long-lasting effectiveness and functionality of rosemary oil in feed while reducing irritation caused by direct exposure, ultimately helping to improve the animal's gut health and overall growth performance.

[0009] Furthermore, the preparation method of the cyclodextrin-coated rosemary oil complex is as follows: by weight, 20-30 parts of rosemary essential oil nanocomposite emulsion and 100-150 parts of anhydrous ethanol are magnetically stirred for 30-45 min to obtain solution A. 20-45 parts of β-cyclodextrin, 100-200 parts of anhydrous ethanol and 100-200 parts of deionized water are stirred in a water bath at 40-55℃ for 10-20 min to obtain solution B. Under room temperature conditions, solution A and solution B are mixed and stirred at 200-300 rpm for 120-240 min. After stirring, the mixture is stored at 1-5℃ for 8-12 h. Then, the solution is vacuum filtered and the powder is collected. The powder is then washed three times with anhydrous ethanol and finally dried in an oven at 40-45℃ for 60-120 min.

[0010] Furthermore, the preparation method of the rosemary essential oil nanocomposite emulsion is as follows: by weight, 30-40 parts of rosemary essential oil, 3-8 parts of α-tocopherol, 3-8 parts of chitosan, 15-32 parts of Tween 40 and 500 parts of deionized water are added to a high-speed homogenizing container and stirred at 10000-13000 rpm for 20-30 min. During the stirring process, the pH of the mixed solution is adjusted to 5.5-6.0 with citric acid. After stirring, a primary rosemary essential oil emulsion is obtained. Then, the primary rosemary essential oil emulsion is placed in an ultrasonic processor and ultrasonically treated at a frequency of 15-20 kHz and a power of 600-700 W for 5-10 min. After ultrasonic treatment, the rosemary essential oil nanocomposite emulsion is obtained.

[0011] Furthermore, the preparation method of the rosemary essential oil is as follows: First, fresh rosemary leaves are dried at an ambient temperature of 20-25°C for 24-48 hours until the moisture content drops below 10%. Then, they are ground into fine rosemary leaf powder with an average particle size of less than 1 mm using a pulverizer. Next, 20-40 parts of the fine rosemary leaf powder and 100 parts of anhydrous ethanol are added to a Soxhlet extraction device at 60-70°C and continuously refluxed for 2-3 hours at 45-55°C. After filtration, the extract is added to a rotary evaporator and evaporated for 60-120 minutes under a vacuum of 0.05-0.09 MPa, a water bath temperature of 40-50°C, and a rotation speed of 60-90 rpm to remove the solvent, finally obtaining rosemary essential oil.

[0012] Furthermore, the mass ratio of rosemary essential oil, α-tocopherol, 3-8 parts chitosan, and Tween 40 is 1:(0.1-0.2):(0.1-0.2):(0.5-0.8).

[0013] Furthermore, the average diameter of the rosemary essential oil nanocomposite emulsion is 50~200nm.

[0014] Furthermore, the zeta potential of the rosemary essential oil nanocomposite emulsion is -30mV to -50mV.

[0015] This invention employs a rosemary essential oil nanocomposite emulsion design primarily to enhance the dispersibility, stability, and bioavailability of rosemary essential oil in feed. By preparing rosemary essential oil into a nanoemulsion form, this invention significantly improves these issues, particularly demonstrating significant advantages in dispersion uniformity and bioavailability. Firstly, the most significant advantage of nanoemulsions lies in their ultra-small particle size. Through high-speed stirring and ultrasonic treatment, rosemary essential oil droplets are refined to the nanoscale, greatly increasing the specific surface area of ​​the droplets and significantly enhancing the bioavailability of rosemary essential oil. In the animal digestive system, nanoscale oil droplets can more easily pass through biological membranes and be rapidly absorbed and utilized. Compared to traditional larger oil droplets, the rosemary essential oil in nanoemulsions can more effectively contact the intestinal mucosa, increasing the absorption rate of its active ingredients and thus enhancing its bioactivity. The high specific surface area of ​​nanoemulsions allows the oil droplets to release their active ingredients more fully, thus exerting a more sustained and significant effect in the animal body. Furthermore, the stability of nanoemulsions is significantly better than that of traditional emulsions. Tween 40 is used to stably disperse essential oils, forming nanoemulsions with particle sizes of 50-200 nm. Chitosan forms a stable protective film on the emulsion surface, enhancing the electrostatic repulsion between emulsion particles and preventing droplet aggregation or sedimentation. Nanoparticle size significantly increases the specific surface area of ​​oil droplets, ensuring uniform distribution of essential oils in feed and avoiding stratification. Simultaneously, the zeta potential of the nanocomposite emulsion is between -30 mV and -50 mV, effectively preventing oil droplet aggregation and further enhancing physical stability. The refined nanoparticles, processed by ultrasound, form a more stable dispersion system in the aqueous phase, maintaining physical stability during long-term storage and preventing oil droplet precipitation or separation. This physical stability is crucial for feed production and storage, ensuring consistent feed quality during transportation and preservation, and extending product shelf life.

[0016] In summary, this invention, through the design of a nanoemulsion, fully utilizes the active ingredients of rosemary essential oil, overcoming its problems of poor dispersibility, volatility, and low absorption efficiency in conventional feeds. The ultra-small particle size of the nanoemulsion improves the dispersibility and stability of rosemary essential oil in the aqueous phase, while significantly enhancing its absorption efficiency in animals. This design not only improves the utilization rate of rosemary essential oil in feed but also ensures its sustained-release effect in the animal's intestines, thereby fully leveraging its antioxidant, antibacterial, and digestive-promoting functions, ultimately improving animal intestinal health and overall nutrient absorption efficiency.

[0017] This invention utilizes a rosemary essential oil nano-composite emulsion and cyclodextrin coating to synergistically enhance the stability and sustained-release properties of the essential oil. The nano-emulsion structure ensures uniform dispersion of the essential oil, increasing its specific surface area and facilitating absorption; cyclodextrin coating further prevents the essential oil from volatilizing and oxidizing, reducing irritation, and prolonging its release time in the animal's digestive tract. The combination of these two components not only improves the bioavailability of rosemary essential oil but also ensures its long-term stability and safety in feed, fully leveraging its antioxidant and gut health-promoting effects.

[0018] Furthermore, the corn flour preparation method is as follows: the raw dry corn kernels are mechanically crushed into corn flour with a particle size of less than 2.0 mm, and then treated with water steam at 100~110°C for 10~20 minutes.

[0019] Furthermore, the method for preparing the straw pellets is as follows: the original straw is mechanically crushed into straw pellets with a particle size of less than 5mm, and then treated with water steam at 100~110°C for 15~30min.

[0020] This invention also provides a method for preparing feed that improves the intestinal health of livestock through rosemary oil, comprising the following steps: according to the formula, each component is added to a biaxial paddle mixer, the mixing rate is set to 80~120 rpm, the mixing time is 8~12 min, and a uniform material is obtained after mixing. Then, the material is granulated using a pellet mill, the granulation temperature is controlled at 60~70°C, and the material is extruded into cylindrical particles with an average particle diameter of 2.0~4.0 mm and an average length of 5.0~10.0 mm. After the particles are formed, they are cooled to room temperature.

[0021] This invention utilizes a scientifically designed preparation method to improve livestock gut health through rosemary oil in feed. Corn flour and straw kernels are mechanically pulverized and steam-treated, respectively, improving the processability and digestibility of the raw materials. After uniform mixing in a twin-shaft paddle mixer, the mixture is granulated into cylindrical particles and cooled to room temperature. This process ensures stable dispersion and slow-release of rosemary oil in the feed, while also improving the feed's physical stability and nutrient absorption efficiency.

[0022] (3) Beneficial technical effects 1. This invention, through the design of a cyclodextrin-encapsulated rosemary oil complex, significantly improves the stability, sustained release, and anti-volatility of rosemary oil in feed, solving the problems of easy volatility, easy oxidation, and strong irritation of essential oils in existing technologies. Compared with traditional processes, the nanoemulsion and encapsulation technology of this invention ensures the long-term stability of rosemary oil during feed processing and storage, while achieving slow release in the animal digestive tract, significantly improving its bioavailability. Furthermore, the encapsulation structure effectively reduces the irritation of rosemary oil, making its application in feed safer. Through precise formulation and process optimization, the components work synergistically to ensure the continuous release and functional performance of rosemary oil, ultimately improving animal gut health, demonstrating broad application prospects and a positive driving force for industry development.

[0023] 2. This invention, through a scientific preparation method, utilizes rosemary oil to improve livestock gut health, demonstrating significant innovation and practical application value. Compared to existing technologies, this invention enhances the processability and digestibility of raw materials through mechanical crushing and steam treatment of corn flour and straw pellets, ensuring feed stability during processing and storage. Uniform mixing and granulation using a twin-shaft paddle mixer ensures even dispersion of rosemary oil, creating a slow-release effect and avoiding the volatilization and uneven distribution problems found in traditional feeds. The synergistic effect of the components optimizes the physical stability of the feed, improves animal nutrient absorption efficiency, extends the feed's shelf life and effectiveness, and promotes innovative development in the feed industry. Attached Figure Description

[0024] Figure 1 This is a macroscopic diagram of the feed prepared in Example 1 of the present invention, which improves the intestinal health of livestock by using rosemary oil.

[0025] Figure 2 This is a transmission electron microscope (TEM) image of the rosemary essential oil nanocomposite emulsion prepared in Example 1 of the present invention.

[0026] Figure 3 This is a scanning electron microscope (SEM) image of the cyclodextrin-coated rosemary oil complex prepared in Example 1 of this invention.

[0027] Figure 4 This is the infrared Fourier spectrum of β-cyclodextrin in Example 1 of the present invention.

[0028] Figure 5 The infrared Fourier spectrum is shown for the rosemary essential oil nanocomposite emulsion prepared in Example 1 of this invention.

[0029] Figure 6 The infrared Fourier spectrum of the cyclodextrin-coated rosemary oil complex prepared in Example 1 of this invention.

[0030] Figure 7This is a transmission electron microscope (TEM) image of the rosemary essential oil nanocomposite emulsion prepared in Comparative Example 2 of this invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0032] Example 1: A feed for improving the gut health of livestock through rosemary oil, the feed comprising the following components in parts by weight: 0.5 parts cyclodextrin-coated rosemary oil complex, 35.0 parts corn flour, 15.0 parts straw kernels, 10.0 parts wheat, 5.0 parts barley, 5.0 parts rapeseed meal, 5.0 parts cottonseed meal, 1.0 part peas, 10.0 parts wheat bran, 1.5 parts bone meal, 1.0 part calcium carbonate, 1.0 part dicalcium phosphate, 0.3 parts salt, 2.0 parts vegetable oil, 5.0 parts alfalfa hay, and 5.0 parts beet pulp; The raw materials for the cyclodextrin-coated rosemary oil complex include rosemary essential oil nanocomposite emulsion and β-cyclodextrin in a mass ratio of 20:20; the cyclodextrin-coated rosemary oil complex is prepared by co-precipitation method.

[0033] The rosemary essential oil nanocomposite emulsion is prepared from the following raw materials in parts by weight: 30 parts rosemary essential oil, 3 parts α-tocopherol, 3 parts chitosan, 15 parts Tween 40 and 500 parts deionized water.

[0034] Specifically, the preparation method of the cyclodextrin-coated rosemary oil complex in this embodiment is as follows: by weight, 20 parts of rosemary essential oil nanocomposite emulsion and 100 parts of anhydrous ethanol are magnetically stirred for 30 min to obtain solution A for later use. Then, 20 parts of β-cyclodextrin, 100 parts of anhydrous ethanol and 100 parts of deionized water are stirred in a water bath at 40°C for 10 min to obtain solution B. Under room temperature conditions, solution A and solution B are mixed and stirred at 200 rpm for 120 min. After stirring, the mixture is stored at 1°C for 8 h. Then, the solution is vacuum filtered and the powder is collected. The powder is then washed three times with anhydrous ethanol and finally dried in an oven at 40°C for 60 min.

[0035] The preparation method of rosemary essential oil nanocomposite emulsion is as follows: 30 parts by weight of rosemary essential oil, 3 parts by weight of α-tocopherol, 3 parts by weight of chitosan, 15 parts by weight of Tween 40 and 500 parts by weight of deionized water are added to a high-speed homogenizing container and stirred at 10,000 rpm for 20 min. During the stirring process, the pH of the mixed solution is adjusted to 5.5 with citric acid. After stirring, a primary rosemary essential oil emulsion is obtained. Then, the primary rosemary essential oil emulsion is placed in an ultrasonic processor and ultrasonically treated at a frequency of 15 kHz and a power of 600 W for 5 min. After ultrasonic treatment, the rosemary essential oil nanocomposite emulsion is obtained.

[0036] The preparation method of rosemary essential oil is as follows: First, fresh rosemary leaves are dried at an ambient temperature of 20°C for 24 hours until the moisture content drops below 10%. Then, they are ground into fine rosemary leaf powder with an average particle size of less than 1 mm using a pulverizer. Next, 20 parts of the fine rosemary leaf powder and 100 parts of anhydrous ethanol are added to a Soxhlet extraction device at 60°C and continuously refluxed for 3 hours at 45°C. After filtration, the extract is added to a rotary evaporator and evaporated for 60 minutes under a vacuum of 0.05 MPa, a water bath temperature of 40°C, and a rotation speed of 60 rpm to remove the solvent, finally obtaining rosemary essential oil.

[0037] The average diameter of the rosemary essential oil nanocomposite emulsion in this embodiment is 50 nm; the Zeta potential of the rosemary essential oil nanocomposite emulsion is -50 mV.

[0038] The method for preparing corn flour in this embodiment is as follows: Raw dry corn kernels are mechanically crushed into corn flour with a particle size of less than 2.0 mm, and then treated with 100°C steam for 10 minutes. The method for preparing straw pellets is as follows: Raw straw is mechanically crushed into straw pellets with a particle size of less than 5 mm, and then treated with 100°C steam for 15 minutes.

[0039] This embodiment also provides a method for preparing feed that improves the intestinal health of livestock through rosemary oil: According to the formula, each component is added to a biaxial paddle mixer, the mixing rate is set to 80 rpm, the mixing time is 8 min, and a uniform material is obtained after mixing. Then, the material is granulated using a pellet mill, the granulation temperature is controlled at 60°C, and the material is extruded into cylindrical particles with an average particle diameter of 2.0 mm and an average length of 5.0 mm. After the particles are formed, they are cooled to room temperature.

[0040] Based on the characterization results, this invention has achieved good results in both feed appearance and microstructure: from Figure 1 As can be seen from the macroscopic photograph, the prepared feed is in the shape of a regular cylinder with a smooth and uniform surface; Figure 2TEM images show that the rosemary essential oil nanocomposite emulsion forms a spherical structure with uniform particle size, with an average diameter of about 50 nm and good dispersibility. Figure 3 SEM images confirmed that cyclodextrin successfully encapsulated rosemary oil, forming a stable complex structure; from Figure 4-6 Infrared spectroscopy analysis revealed that β-cyclodextrin at 3396 cm⁻¹ -1 The characteristic peak of the -OH group appears at 2922 cm⁻¹. -1 The stretching vibration of the CH bond is shown at 1638 cm. -1 The peak at 1414 cm⁻¹ is attributed to the bending of OH groups by adsorbed water molecules. -1 The peak is an overlap of the plane bending of -CH2 and OH, at 1035 cm⁻¹. -1 and 1157cm -1 The strong peak at 3481 cm⁻¹ corresponds to the stretching vibrations of CO, C₂, and COC bonds; the cyclodextrin-encapsulated rosemary oil complex shows a peak at 3481 cm⁻¹. -1 An OH stretching vibration peak appears at 2964 cm⁻¹. -1 and 2867cm -1 The asymmetric and symmetric stretching vibrations of CH3 and CH2 are shown at 1743 cm. -1 The sharp peak at 1448 cm⁻¹ is a characteristic peak of the C=O group. -1 and 1377cm -1 The points correspond to the bending vibrations of CH3, CH2, and OH, respectively, at 1215 cm. -1 and 1711cm -1 The peak at 984 cm⁻¹ is attributed to the stretching of C / C and CO bonds. -1 The area represents the out-of-plane stretching vibrations of CH and OH.

[0041] Example 2: A feed for improving the gut health of livestock through rosemary oil, the feed comprising the following components in parts by weight: 1.1 parts cyclodextrin-coated rosemary oil complex, 38.0 parts corn flour, 18.0 parts straw kernels, 13.0 parts wheat, 7.0 parts barley, 7.0 parts rapeseed meal, 7.0 parts cottonseed meal, 4.0 parts peas, 11.5 parts wheat bran, 1.7 parts bone meal, 1.3 parts calcium carbonate, 1.3 parts dicalcium phosphate, 0.7 parts salt, 2.9 parts vegetable oil, 7.0 parts alfalfa hay, and 7.0 parts beet pulp; The raw materials for the cyclodextrin-coated rosemary oil complex include a rosemary essential oil nanocomposite emulsion and β-cyclodextrin in a mass ratio of 23:25; the cyclodextrin-coated rosemary oil complex is prepared by a co-precipitation method. The rosemary essential oil nanocomposite emulsion is prepared from the following raw materials in parts by weight: 33 parts rosemary essential oil, 4 parts α-tocopherol, 4 parts chitosan, 19 parts Tween 40, and 500 parts deionized water.

[0042] Specifically, the preparation method of the cyclodextrin-coated rosemary oil complex in this embodiment is as follows: by weight, 23 parts of rosemary essential oil nanocomposite emulsion and 115 parts of anhydrous ethanol are magnetically stirred for 35 min to obtain solution A for later use. Then, 25 parts of β-cyclodextrin, 130 parts of anhydrous ethanol and 130 parts of deionized water are stirred in a water bath at 47°C for 14 min to obtain solution B. Under room temperature conditions, solution A and solution B are mixed and stirred at 230 rpm for 165 min. After stirring, the mixture is stored at 2°C for 9 h. Then, the solution is vacuum filtered and the powder is collected. The powder is then washed three times with anhydrous ethanol and finally dried in an oven at 44°C for 90 min.

[0043] The preparation method of rosemary essential oil nanocomposite emulsion is as follows: 33 parts by weight of rosemary essential oil, 4 parts by weight of α-tocopherol, 4 parts by weight of chitosan, 19 parts by weight of Tween 40 and 500 parts by weight of deionized water are added to a high-speed homogenizing container and stirred at 11,100 rpm for 24 min. During the stirring process, the pH of the mixed solution is adjusted to 5.9 with citric acid. After stirring, a primary rosemary essential oil emulsion is obtained. Then, the primary rosemary essential oil emulsion is placed in an ultrasonic processor and ultrasonically treated at a frequency of 17 kHz and a power of 625 W for 6 min. After ultrasonic treatment, the rosemary essential oil nanocomposite emulsion is obtained.

[0044] The preparation method of rosemary essential oil is as follows: First, fresh rosemary leaves are dried at an ambient temperature of 23°C for 29 hours until the moisture content drops below 10%. Then, they are ground into fine rosemary leaf powder with an average particle size of less than 1 mm using a pulverizer. Next, 26 parts of the fine rosemary leaf powder and 100 parts of anhydrous ethanol are added to a Soxhlet extraction device at 64°C and continuously refluxed at 51°C for 2.5 hours. After filtration, the extract is added to a rotary evaporator and evaporated for 75 minutes under a vacuum of 0.07 MPa, a water bath temperature of 46°C, and a rotation speed of 72 rpm to remove the solvent. Finally, rosemary essential oil is obtained.

[0045] In this embodiment, the average diameter of the rosemary essential oil nanoemulsion is 110 nm; the zeta potential of the rosemary essential oil nanocomposite emulsion is -45 mV.

[0046] The method for preparing corn flour in this embodiment is as follows: Raw dry corn kernels are mechanically crushed into corn flour with a particle size of less than 2.0 mm, and then treated with steam at 105°C for 15 minutes. The method for preparing straw pellets is as follows: Raw straw is mechanically crushed into straw pellets with a particle size of less than 5 mm, and then treated with steam at 105°C for 21 minutes.

[0047] This embodiment also provides a method for preparing feed that improves the intestinal health of livestock through rosemary oil: According to the formula, each component is added to a biaxial paddle mixer, the mixing rate is set to 95 rpm, the mixing time is 10 min, and after mixing, a uniform material is obtained. Then, the material is granulated using a pellet mill, the granulation temperature is controlled at 65°C, and the material is extruded into cylindrical particles with an average particle diameter of 3.0 mm and an average length of 7.0 mm. After the particles are formed, they are cooled to room temperature.

[0048] Example 3: A feed for improving the gut health of livestock through rosemary oil, the feed comprising the following components in parts by weight: 1.5 parts cyclodextrin-coated rosemary oil complex, 41.0 parts corn flour, 21.0 parts straw kernels, 16.0 parts wheat, 8.0 parts barley, 8.0 parts rapeseed meal, 8.0 parts cottonseed meal, 7.0 parts peas, 13.0 parts wheat bran, 1.8 parts bone meal, 1.6 parts calcium carbonate, 1.6 parts dicalcium phosphate, 1.1 parts salt, 3.8 parts vegetable oil, 8.0 parts alfalfa hay, and 8.0 parts beet pulp; The raw materials for the cyclodextrin-coated rosemary oil complex include a rosemary essential oil nanocomposite emulsion and β-cyclodextrin in a mass ratio of 26:33; the cyclodextrin-coated rosemary oil complex is prepared by a co-precipitation method. The rosemary essential oil nanocomposite emulsion is prepared from the following raw materials in parts by weight: 36 parts rosemary essential oil, 6 parts α-tocopherol, 6 parts chitosan, 28 parts Tween 40, and 500 parts deionized water.

[0049] Specifically, the preparation method of the cyclodextrin-coated rosemary oil complex in this embodiment is as follows: by weight, 26 parts of rosemary essential oil nanocomposite emulsion and 130 parts of anhydrous ethanol are magnetically stirred for 38 min to obtain solution A for later use. Then, 33 parts of β-cyclodextrin, 160 parts of anhydrous ethanol and 160 parts of deionized water are stirred in a water bath at 50°C for 16 min to obtain solution B. Under room temperature conditions, solution A and solution B are mixed and stirred at 260 rpm for 192 min. After stirring, the mixture is stored at 3°C ​​for 10 h. Then, the solution is vacuum filtered and the powder is collected. The powder is then washed three times with anhydrous ethanol and finally dried in an oven at 45°C for 100 min.

[0050] The preparation method of rosemary essential oil nanocomposite emulsion is as follows: 36 parts by weight of rosemary essential oil, 6 parts by weight of α-tocopherol, 6 parts by weight of chitosan, 28 parts by weight of Tween 40 and 500 parts by weight of deionized water are added to a high-speed homogenizing container and stirred at 11800 rpm for 26 min. During the stirring process, the pH of the mixed solution is adjusted to 6.1 with citric acid. After stirring, a primary rosemary essential oil emulsion is obtained. Then, the primary rosemary essential oil emulsion is placed in an ultrasonic processor and ultrasonically treated at a frequency of 19 kHz and a power of 660 W for 7 min. After ultrasonic treatment, the rosemary essential oil nanocomposite emulsion is obtained.

[0051] The preparation method of rosemary essential oil is as follows: First, fresh rosemary leaves are dried at an ambient temperature of 23°C for 34 hours until the moisture content drops below 10%. Then, they are ground into fine rosemary leaf powder with an average particle size of less than 1 mm using a pulverizer. Next, 32 parts of the fine rosemary leaf powder and 100 parts of anhydrous ethanol are added to a Soxhlet extraction device at 67°C and continuously refluxed at 52°C for 2.5 hours. After filtration, the extract is added to a rotary evaporator and evaporated for 98 minutes under a vacuum of 0.07 MPa, a water bath temperature of 47°C, and a rotation speed of 78 rpm to remove the solvent. Finally, rosemary essential oil is obtained.

[0052] The average diameter of the rosemary essential oil nanocomposite emulsion in this embodiment is 170 nm; the Zeta potential of the rosemary essential oil nanocomposite emulsion is -35 mV.

[0053] The method for preparing corn flour in this embodiment is as follows: Raw dry corn kernels are mechanically crushed into corn flour with a particle size of less than 2.0 mm, and then treated with steam at 107°C for 17 minutes. The method for preparing straw pellets is as follows: Raw straw is mechanically crushed into straw pellets with a particle size of less than 5 mm, and then treated with steam at 107°C for 24 minutes.

[0054] This embodiment also provides a method for preparing feed that improves the intestinal health of livestock through rosemary oil: According to the formula, each component is added to a biaxial paddle mixer, the mixing rate is set to 105 rpm, the mixing time is 10 min, and a uniform material is obtained after mixing. Then, the material is granulated using a pellet mill, the granulation temperature is controlled at 68°C, and the material is extruded into cylindrical particles with an average particle diameter of 3.0 mm and an average length of 8.0 mm. After the particles are formed, they are cooled to room temperature.

[0055] Example 4: A feed for improving the gut health of livestock through rosemary oil, the feed comprising the following components in parts by weight: 2.0 parts cyclodextrin-coated rosemary oil complex, 45.0 parts corn flour, 25.0 parts straw kernels, 20.0 parts wheat, 10.0 parts barley, 10.0 parts rapeseed meal, 10.0 parts cottonseed meal, 10.0 parts peas, 15.0 parts wheat bran, 2.0 parts bone meal, 2.0 parts calcium carbonate, 2.0 parts dicalcium phosphate, 1.5 parts salt, 5.0 parts vegetable oil, 10.0 parts alfalfa hay, and 10.0 parts beet pulp; The raw materials for the cyclodextrin-coated rosemary oil complex include a rosemary essential oil nanocomposite emulsion and β-cyclodextrin in a mass ratio of 30:45; the cyclodextrin-coated rosemary oil complex is prepared by a co-precipitation method. The rosemary essential oil nanocomposite emulsion is prepared from the following raw materials in parts by weight: 40 parts rosemary essential oil, 8 parts α-tocopherol, 8 parts chitosan, 32 parts Tween 40, and 500 parts deionized water.

[0056] Specifically, the preparation method of the cyclodextrin-coated rosemary oil complex in this embodiment is as follows: by weight, 30 parts of rosemary essential oil nanocomposite emulsion and 150 parts of anhydrous ethanol are magnetically stirred for 45 min to obtain solution A; 45 parts of β-cyclodextrin, 200 parts of anhydrous ethanol and 200 parts of deionized water are stirred in a water bath at 55°C for 20 min to obtain solution B. Under room temperature conditions, solution A and solution B are mixed and stirred at 300 rpm for 240 min. After stirring, the mixture is stored at 5°C for 12 h, then the solution is vacuum filtered and the powder is collected. The powder is then washed three times with anhydrous ethanol and finally dried in an oven at 45°C for 120 min.

[0057] The preparation method of rosemary essential oil nanocomposite emulsion is as follows: 40 parts by weight of rosemary essential oil, 8 parts by weight of α-tocopherol, 8 parts by weight of chitosan, 32 parts by weight of Tween 40 and 500 parts by weight of deionized water are added to a high-speed homogenizing container and stirred at 13,000 rpm for 30 min. During the stirring process, the pH of the mixed solution is adjusted to 6.5 with citric acid. After stirring, a primary rosemary essential oil emulsion is obtained. Then, the primary rosemary essential oil emulsion is placed in an ultrasonic processor and ultrasonically treated at a frequency of 20 kHz and a power of 700 W for 10 min. After ultrasonic treatment, the rosemary essential oil nanocomposite emulsion is obtained.

[0058] The preparation method of rosemary essential oil is as follows: First, fresh rosemary leaves are dried at an ambient temperature of 25°C for 48 hours until the moisture content drops below 10%. Then, they are ground into fine rosemary leaf powder with an average particle size of less than 1 mm using a pulverizer. Next, 40 parts of the fine rosemary leaf powder and 100 parts of anhydrous ethanol are added to a Soxhlet extraction device at 70°C and continuously refluxed for 3 hours at 55°C. After filtration, the extract is added to a rotary evaporator and evaporated for 120 minutes under a vacuum of 0.09 MPa, a water bath temperature of 50°C, and a rotation speed of 90 rpm to remove the solvent, finally obtaining rosemary essential oil.

[0059] The average diameter of the rosemary essential oil nanocomposite emulsion in this embodiment is 200 nm; the Zeta potential of the rosemary essential oil nanocomposite emulsion is -30 mV.

[0060] The method for preparing corn flour in this embodiment is as follows: Raw dry corn kernels are mechanically crushed into corn flour with a particle size of less than 2.0 mm, and then treated with steam at 110°C for 20 minutes. The method for preparing straw pellets is as follows: Raw straw is mechanically crushed into straw pellets with a particle size of less than 5 mm, and then treated with steam at 110°C for 30 minutes.

[0061] This embodiment also provides a method for preparing feed that improves the intestinal health of livestock through rosemary oil: According to the formula, each component is added to a biaxial paddle mixer, the mixing rate is set to 120 rpm, the mixing time is 12 min, and a uniform material is obtained after mixing. Then, the material is granulated using a pellet mill, the granulation temperature is controlled at 70°C, and the material is extruded into cylindrical particles with an average particle diameter of 4.0 mm and an average length of 10.0 mm. After the particles are formed, they are cooled to room temperature.

[0062] Comparative Example 1: The preparation method is basically the same as Example 1, except that the amount of β-cyclodextrin used to prepare the rosemary oil complex coated with cyclodextrin is 10 parts, so the coating rate of the rosemary essential oil nanocomposite emulsion is insufficient.

[0063] Comparative Example 2: The process is essentially the same as in Example 1, except that the amount of Tween 40 used in preparing the rosemary essential oil nanocomposite emulsion is 10 parts, corresponding to a rosemary essential oil to Tween 40 mass ratio of 3:1. The average diameter of the rosemary essential oil nanocomposite emulsion increases to 250 nm, and the Zeta potential decreases to -25 mV. Figure 7 As can be seen, the average particle size of the nanoemulsion increased significantly to 250 nm at this time, indicating that the amount of emulsifier has a significant impact on the particle size.

[0064] Comparative Example 3: The preparation of the rosemary essential oil nanocomposite emulsion was basically the same as that in Example 1, except that no α-tocopherol was added.

[0065] Comparative Example 4: The preparation method is basically the same as Example 1, except that chitosan was not added to the rosemary essential oil nanocomposite emulsion.

[0066] Comparative Example 5: The preparation of the rosemary essential oil nanocomposite emulsion was basically the same as in Example 1, except that the pH of the mixed solution was adjusted to 5.0 with citric acid, the average diameter of the rosemary essential oil nanocomposite emulsion was increased to 220 nm, and the Zeta potential was reduced to -28 mV.

[0067] Comparative Example 6: The process was basically the same as in Example 1, except that the stirring rate for preparing the rosemary essential oil nanocomposite emulsion was 8000 rpm, the average diameter of the rosemary essential oil nanocomposite emulsion was increased to 240 nm, and the Zeta potential was reduced to -30 mV.

[0068] Comparative Example 7: It is basically the same as Example 1, except that an equal amount of rosemary essential oil is used instead of rosemary essential oil nanocomposite emulsion.

[0069] The preparation method of the cyclodextrin-coated rosemary oil complex in this comparative example is as follows: 30 parts by weight of rosemary essential oil and 150 parts by weight of anhydrous ethanol were magnetically stirred for 45 min to obtain solution A; 45 parts by weight of β-cyclodextrin, 200 parts by weight of anhydrous ethanol and 200 parts by weight of deionized water were stirred in a water bath at 55°C for 20 min to obtain solution B. At room temperature, solutions A and B were mixed and stirred at 300 rpm for 240 min. After stirring, the mixture was stored at 5°C for 12 h. The solution was then vacuum filtered and the powder was collected. The powder was then washed three times with anhydrous ethanol and finally dried completely in an oven at 50°C.

[0070] Comparative Example 8: The process is basically the same as in Example 1, except that the β-cyclodextrin and rosemary essential oil nanocomposite emulsions are added separately to the biaxial paddle mixer, so there is no coating relationship between the two.

[0071] Performance testing: This experiment aimed to investigate the effects of cyclodextrin-encapsulated rosemary oil complex on improving intestinal health in livestock. Seventy-two healthy farmed goats, all similar in parity, age at lactation, milk yield, and body weight, were randomly divided into 12 groups of six goats each. They were fed daily the amounts of the rosemary oil-encapsulated feed specified in Examples 1-4 and Comparative Examples 1-8 for a 52-day experimental period, including a 10-day pre-trial period and a 42-day trial period. Feed was provided twice daily, at 08:00 and 16:00, ensuring approximately 5% uneaten feed remained in each pen. Goats had free access to food and water. Milking was conducted daily at 07:00 and 18:00, with other feeding and management following standard farm practices. The effects of the feeds from the examples and comparative examples on intestinal health, production performance (e.g., milk yield), and immunity in dairy goats were observed.

[0072] Fecal sample collection: Fresh feces from dairy goats were collected for five consecutive days, from days 38 to 42 of the trial period. The feces were mixed thoroughly, and 500g of the mixture was divided into two portions: one portion was treated with 10mL of 10% nitrogen-fixing sulfate per 100g of fresh sample for crude protein content determination; the other portion was used for other nutrient component determination without sulfuric acid. After weighing, the fecal samples were dried at 65℃ for 48 hours. After determining the initial moisture content, the samples were pulverized, passed through a 40-mesh sieve, and placed in sealed bags for subsequent indicator determination.

[0073] Rumen fluid collection: On the morning of day 42 of the trial period, before feeding, six dairy goats were randomly selected from each group. A soft catheter with a syringe was inserted into the rumen through the mouth to extract rumen fluid, which was then divided into two portions. After filtering through four layers of gauze, one portion was placed in a clean disposable paper cup for immediate pH measurement; the other portion was divided into five 2mL cryovials and stored at -80℃ for the determination of rumen fermentation parameters and microorganisms.

[0074] Apparent nutrient digestibility: Dry matter (DM), crude protein (CP), crude ash (Ash), and neutral detergent fiber (NDF) were tested in diets and fecal samples. During the trial period, daily feed intake and uneaten feed were recorded, the nutrient content in the diet was measured, and nutrient intake per sheep was calculated on a pen-by-pen basis. The digestibility of each nutrient in the diet was determined using the endogenous indicator method, requiring testing of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) intake.

[0075] After rumen fluid filtration, the pH value was measured using a portable pH meter (AS700, Shanghai Sanxin Instrument Factory). For volatile fatty acid (VFA) determination, 1.5 mL of rumen fluid and 0.15 mL of 25% metaphosphate were placed in a centrifuge tube, frozen overnight at -20°C, and then centrifuged at 10,000 rpm for 10 minutes after thawing. Subsequently, 0.6 mL of the sample was filtered through a 45 μm microporous membrane and analyzed by gas chromatography (GC-2010-Puls, Shimadzu, Japan). After extracting total microbial DNA from the rumen fluid samples, DNA quality was assessed using 1% agarose gel electrophoresis, and concentration and purity were determined using a NanoDrop 2000. PCR amplification of the 16S rRNA gene V3-V4 region was performed using primers 338F / 806R (ABIGeneAmp®9700). PCR products were detected using 2% agarose gel electrophoresis, recovered, and quantified using a Quantus™ Fluorometer. Library construction was performed using the NEXTFLEX Rapid DNA-Seq Kit. Sequences were clustered into OTUs at a 97% similarity level using Uparse software, and species annotation was performed on the OTU sequences using RDPclassifier software. Community composition and differences in species abundance between the control and experimental groups were analyzed. The Beta diversity distance matrix was calculated using Qiime software and plotted using R language; Mothur was used for Alpha diversity analysis, and Tax4Fun software was used for functional prediction. The concentrations of acetic acid, propionic acid, butyric acid, isobutyric acid, total volatile fatty acids (TVFA), and pH in rumen fluid needed to be tested.

[0076] The project parameters of Examples 1-4 and Comparative Examples 1-8 are summarized in Table 1.

[0077] As shown in Table 1, the main difference between Comparative Example 1 and Example 1 lies in the amount of β-cyclodextrin used in preparing the rosemary oil complex coated with cyclodextrin: 10 parts were used, resulting in insufficient coating of the rosemary essential oil nanocomposite emulsion. The table also shows that the apparent digestibility of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) in Example 1 were significantly higher than those in Comparative Example 1. This significant improvement in digestibility is attributed to the higher coating rate of the rosemary essential oil complex, which better maintains the stability of the active ingredients, promoting digestion and absorption. In Comparative Example 1, the insufficient coating rate resulted in inadequate release of the effective components of the rosemary essential oil, leading to decreased digestibility. Furthermore, Example 1 also exhibited higher concentrations of volatile fatty acids (such as acetic acid, propionic acid, and butyric acid) and total volatile fatty acids (TVFA) levels, indicating better rumen fermentation function. This is also attributed to the higher coating rate helping to maintain the activity of the rosemary essential oil.

[0078] The main difference between Comparative Example 2 and Example 1 lies in the amount of Tween 40 used in preparing the rosemary essential oil nanocomposite emulsion. This resulted in an improper ratio of rosemary essential oil to emulsifier, increasing the average emulsion diameter to 250 nm and decreasing the zeta potential to -25 mV. As shown in the table, the digestibility and volatile fatty acid levels of Example 1 were significantly higher than those of Comparative Example 2. The larger particle size and decreased zeta potential of the nanoemulsion affected its stability and bioavailability, leading to an excessively rapid or uneven release rate of rosemary oil in the rumen, thus impacting digestion, absorption, and fermentation efficiency. In Example 1, thanks to the suitable emulsion particle size and zeta potential, the active ingredients were released more evenly, thereby improving nutrient digestibility and rumen fermentation efficiency.

[0079] The main difference between Comparative Example 3 and Example 1 is the absence of α-tocopherol. As shown in Table 1, the absence of α-tocopherol resulted in a decrease in the apparent digestibility of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF). Simultaneously, the formation of acetic acid, propionic acid, butyric acid, and isobutyric acid decreased, and the total volatile fatty acids (TVFA) also slightly decreased. This is because α-tocopherol, as an antioxidant, can enhance the stability of the emulsion system, reduce oxidative degradation, and improve the effectiveness of active ingredients, thereby promoting microbial metabolic reactions and the digestibility and utilization of nutrients. Without α-tocopherol, the emulsion stability decreased, leading to an overall decline in its performance.

[0080] The main difference between Comparative Example 4 and Example 1 is the absence of chitosan. As shown in Table 1, the absence of chitosan also resulted in slightly lower apparent digestibility of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) compared to Example 1. Simultaneously, the formation of acetic acid, propionic acid, butyric acid, and isobutyric acid all decreased, total volatile fatty acids (TVFA) slightly decreased, and the pH value also slightly decreased. This is because chitosan possesses excellent emulsion stability and biofunctionality, improving the adsorption and mass transfer properties of emulsions and providing a more suitable metabolic environment for microorganisms. Without chitosan, the functionality and stability of the emulsion are reduced, affecting digestibility and the formation of volatile fatty acids.

[0081] The main difference between Comparative Example 5 and Example 1 is that the pH of the rosemary essential oil nanocomposite emulsion was adjusted to 5.0, resulting in an increase in the average diameter of the emulsion to 220 nm and a decrease in the zeta potential to -28 mV. As can be seen from the table, the digestibility and rumen fermentation parameters of Example 1 are superior to those of Comparative Example 5. The pH adjustment affected the stability of the emulsion, and the larger average diameter reduced the dispersibility of the rosemary oil, thus affecting the release and absorption efficiency of its active ingredients in the rumen. Therefore, in Comparative Example 5, due to the larger emulsion particle size and lower zeta potential, the bioavailability of the rosemary oil decreased, resulting in lower digestibility and volatile fatty acid levels compared to Example 1.

[0082] The main difference between Comparative Example 6 and Example 1 is that the stirring rate was 8000 rpm during the preparation of the rosemary essential oil nanocomposite emulsion, resulting in an increase in the average diameter of the emulsion to 240 nm and a decrease in the Zeta potential to -30 mV. As can be seen from the table, the digestibility and rumen fermentation parameters of Example 1 are significantly higher than those of Comparative Example 6. The reduced stirring rate affected the particle size control of the nanoemulsion; larger particle sizes led to uneven release of the active ingredients, affecting their effective absorption. In Example 1, the appropriate stirring rate resulted in smaller and more uniform nanoemulsion particle sizes, allowing for the gradual release of active ingredients in the rumen, thereby significantly improving digestibility and fermentation efficiency.

[0083] The main difference between Comparative Example 7 and Example 1 is that an equal amount of rosemary essential oil was used instead of rosemary nanoemulsion. As can be seen from the table, the digestibility and volatile fatty acid levels of Example 1 are significantly better than those of Comparative Example 7. This is because nano-sizing significantly increases the surface area of ​​rosemary essential oil, improving its dispersibility and bioavailability in the rumen. In Comparative Example 7, without nano-sizing, the dispersibility of rosemary essential oil was poor, affecting its absorption and utilization, resulting in lower performance indicators.

[0084] The main difference between Comparative Example 8 and Example 1 is that the β-cyclodextrin and rosemary essential oil nanocomposite emulsion were added separately without any coating relationship. As can be seen from the table, the digestibility and volatile fatty acid levels of Example 1 were significantly higher than those of Comparative Example 8. The cyclodextrin coating technology can effectively protect the active ingredients of rosemary essential oil, preventing premature degradation or inactivation in the rumen. In Comparative Example 8, however, the lack of coating between cyclodextrin and rosemary essential oil led to a significant decrease in the stability and bioavailability of rosemary oil in the rumen, thus affecting digestibility and fermentation efficiency.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any equivalent structural transformations made under the concept of the present invention and using the contents of the specification and drawings of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A feed that improves the intestinal health of livestock through rosemary oil, characterized in that, The feed comprises the following components in parts by weight: 0.5-2.0 parts cyclodextrin-coated rosemary oil complex, 35.0-45.0 parts corn flour, 15.0-25.0 parts straw grains, 10.0-20.0 parts wheat, 5.0-10.0 parts barley, 5.0-10.0 parts rapeseed meal, 5.0-10.0 parts cottonseed meal, 1.0-10.0 parts peas, 10.0-15.0 parts wheat bran, 1.5-2.0 parts bone meal, 1.0-2.0 parts calcium carbonate, 1.0-2.0 parts dicalcium phosphate, 0.3-1.5 parts salt, 2.0-5.0 parts vegetable oil, 5.0-10.0 parts alfalfa hay, and 5.0-10.0 parts beet meal; The raw materials for the cyclodextrin-coated rosemary oil complex include a rosemary essential oil nanocomposite emulsion and β-cyclodextrin in a mass ratio of 20-30:20-45; the cyclodextrin-coated rosemary oil complex is prepared by a co-precipitation method. The rosemary essential oil nanocomposite emulsion is prepared from the following raw materials in parts by weight: 30-40 parts rosemary essential oil, 3-8 parts α-tocopherol, 3-8 parts chitosan, 15-32 parts Tween 40 and 500 parts deionized water.

2. The feed for improving livestock gut health using rosemary oil as described in claim 1, characterized in that, The preparation method of the cyclodextrin-coated rosemary oil complex is as follows: 20-30 parts by weight of rosemary essential oil nanocomposite emulsion and 100-150 parts by weight of anhydrous ethanol are magnetically stirred for 30-45 min to obtain solution A; 20-45 parts by weight of β-cyclodextrin, 100-200 parts by weight of anhydrous ethanol and 100-200 parts by weight of deionized water are stirred in a water bath at 40-55℃ for 10-20 min to obtain solution B; at room temperature, solution A and solution B are mixed and stirred at 200-300 rpm for 120-240 min; after stirring, the mixture is stored at 1-5℃ for 8-12 h; then the solution is vacuum filtered and the powder is collected; the powder is then washed three times with anhydrous ethanol; finally, the powder is dried in an oven at 40-45℃ for 60-120 min.

3. A feed for improving livestock gut health using rosemary oil as described in claim 1 or 2, characterized in that, The preparation method of the rosemary essential oil nanocomposite emulsion is as follows: by weight, 30-40 parts of rosemary essential oil, 3-8 parts of α-tocopherol, 3-8 parts of chitosan, 15-32 parts of Tween 40 and 500 parts of deionized water are added to a high-speed homogenizing container and stirred at 10000-13000 rpm for 20-30 min. During the stirring process, the pH of the mixed solution is adjusted to 5.5-6.0 with citric acid. After stirring, a primary rosemary essential oil emulsion is obtained. Then, the primary rosemary essential oil emulsion is placed in an ultrasonic processor and ultrasonically treated at a frequency of 15-20 kHz and a power of 600-700 W for 5-10 min. After ultrasonic treatment, the rosemary essential oil nanocomposite emulsion is obtained.

4. The feed for improving livestock gut health using rosemary oil as described in claim 3, characterized in that, The preparation method of rosemary essential oil is as follows: First, fresh rosemary leaves are dried at an ambient temperature of 20-25°C for 24-48 hours until the moisture content drops below 10%. Then, they are ground into fine rosemary leaf powder with an average particle size of less than 1 mm using a pulverizer. Next, 20-40 parts of the fine rosemary leaf powder and 100 parts of anhydrous ethanol are added to a Soxhlet extraction device at 60-70°C and continuously refluxed for 2-3 hours at 45-55°C. After filtration, the extract is added to a rotary evaporator and evaporated for 60-120 minutes under a vacuum of 0.05-0.09 MPa, a water bath temperature of 40-50°C, and a rotation speed of 60-90 rpm to remove the solvent, finally obtaining rosemary essential oil.

5. A feed for improving livestock gut health using rosemary oil as described in claim 3, characterized in that, The mass ratio of rosemary essential oil, α-tocopherol, 3-8 parts chitosan, and Tween 40 is 1:(0.1-0.2):(0.1-0.2):(0.5-0.8).

6. A feed for improving livestock gut health using rosemary oil as described in claim 1 or 2, characterized in that, The average diameter of the rosemary essential oil nanocomposite emulsion is 50~200nm.

7. A feed for improving livestock gut health using rosemary oil as described in claim 1 or 2, characterized in that, The zeta potential of the rosemary essential oil nanocomposite emulsion is -30mV to -50mV.

8. A feed for improving livestock gut health using rosemary oil as described in claim 1, characterized in that, The method for preparing corn flour is as follows: the raw dry corn kernels are mechanically crushed into corn flour with a particle size of less than 2.0 mm, and then treated with water steam at 100~110°C for 10~20 minutes.

9. A feed for improving livestock gut health using rosemary oil as described in claim 1, characterized in that, The method for preparing the straw pellets is as follows: the original straw is mechanically crushed into straw pellets with a particle size of less than 5mm, and then treated with water steam at 100~110°C for 15~30min.

10. A method for preparing feed that improves the intestinal health of livestock using rosemary oil, as described in any one of claims 1 to 9, characterized in that, Includes the following steps: According to the formula, add each component to a twin-shaft paddle mixer, set the mixing rate to 80~120 rpm, and the mixing time to 8~12 min. After mixing, a uniform material is obtained. Then, the material is granulated using a pellet mill, with the granulation temperature controlled at 60~70°C. The material is extruded into cylindrical particles with an average particle diameter of 2.0~4.0 mm and an average length of 5.0~10.0 mm. After the particles are formed, they are cooled to room temperature.

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