Rumen-protected histidine, preparation method and application thereof

Abstract

The application discloses a kind of over rumen histidine and its preparation method and application.Histidine crystal is first pulverized, is mixed uniformly with sodium carboxymethyl cellulose and calcium stearate and water in high-speed shearing granulator, then is put into rotary granulator, and wet granule is obtained by a certain screen under external force, a certain quality of wet granule is put into shot blasting machine and is blasted, and micro-pellet with larger specific gravity and better compactness is obtained, and core material is obtained after drying.The coating material is selected as over rumen fat powder and ethyl cellulose, and is melted in a centralized melting tank, and the bottom spray fluidized bed granulator is used to coat the histidine core material to obtain the finished product.The over rumen histidine prepared in the application has the characteristics of stable product quality, good reproducibility of small intestine release effect, high bioavailability and the like.The over rumen histidine prepared in the application has a significant effect of improving the milk yield and milk protein rate of lactating dairy cows, and helps to improve the economic benefits of ranch.

Description

Technical Field

[0001] This invention belongs to the field of animal feed additive technology, specifically relating to a rumen-protected histidine, its preparation method, and its application. Background Technology

[0002] The rumen of ruminants possesses a powerful anaerobic fermentation capacity, ensuring the degradation and utilization of crude fiber feed. With the vigorous promotion and implementation of feed-saving technologies in my country's livestock farming, research on low-protein diets for ruminants is increasing. Combining this with small intestinal amino acid balancing technology can reduce dietary protein by 2-4 percentage points. Histidine is designated as the first limiting amino acid in low-protein diets for dairy cows, especially those primarily composed of roughage.

[0003] Because rumen microorganisms in dairy cows can degrade crystalline histidine, direct addition would be ineffective and wasteful. Previous studies have shown that histidine can be made effective and improve dairy cow production performance through small intestinal instillation or rumen-protected technology. Rumen-protected histidine is more suitable for farm production needs, and currently, fats and polymers are commonly used as coating materials to ensure that it can pass through the rumen and be released in the small intestine.

[0004] However, existing rumen-protected histidine formulations and preparations suffer from low histidine content and over-coating. Therefore, there is an urgent need to provide a rumen-protected histidine with high histidine content and high release rate. Summary of the Invention

[0005] This invention provides a rumen-protected histidine composition, wherein the histidine content or mass ratio is 30%-60%.

[0006] According to an embodiment of the present invention, the content or mass ratio of histidine is 32%-55%, for example 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%.

[0007] According to an embodiment of the present invention, the rumen-protected histidine composition further comprises a binder; preferably, the content or mass ratio of the binder is 0.1%-3%, 0.2%-2.0%, for example 0.1%, 0.3%, 0.5%, 0.8%, 1.0%, 1.3%, 1.5%, 1.8%, 2.0%, 2.3%, 2.5%, 2.8%, 3.0%.

[0008] According to an embodiment of the present invention, the rumen-protected histidine composition further comprises a coating material; preferably, the content or mass ratio of the coating material is 40%-60%, 42%-58%; for example, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%.

[0009] According to an embodiment of the present invention, the rumen-protected histidine composition comprises the following components: histidine, binder, and coating material; preferably, the mass ratio of histidine, binder, and coating material is 30-60:0.1-3:40-60; preferably, the mass ratio of histidine, binder, and coating material is 32-55:0.5-2:45-55, more preferably 35-52:0.8-1.5:45-52, for example 50:1:49, 40:1:49, or 40-50:1:49.

[0010] According to an embodiment of the present invention, the histidine is histidine that has been pulverized. According to an embodiment of the present invention, the particle size of the histidine is 100-120 mesh, for example, 100 mesh or 120 mesh. According to an embodiment of the present invention, the size of the fine particles of the pulverized histidine is greater than 125 μm.

[0011] According to an embodiment of the present invention, the adhesive is selected from sodium carboxymethyl cellulose, or a combination of sodium carboxymethyl cellulose and calcium stearate. According to an embodiment of the present invention, the adhesive comprises sodium carboxymethyl cellulose and calcium stearate. According to an embodiment of the present invention, the mass ratio of sodium carboxymethyl cellulose to calcium stearate is 8-10:0-2, for example 8:2, 8.5:1.5, 9:1, 9.5:0.5, or 10:0.

[0012] According to an embodiment of the present invention, the coating material comprises: rumen-protected fat powder and ethyl cellulose. According to an embodiment of the present invention, the mass ratio of rumen-protected fat powder to ethyl cellulose is 47-48.8:0.2-2.0, preferably 47.5-48.5:0.5-1.5, for example 48.8:0.2, 48.5:0.5, 48.2:0.8, 48:1, 47.8:1.2, and 47.5:1.5.

[0013] According to an embodiment of the present invention, the mass ratio of histidine, binder, rumen-protected fat powder, and ethyl cellulose is 50:1:48.5:0.5, 40:1:48.5:0.5, or 40-50:1:48.5:0.5. According to an embodiment of the present invention, the mass ratio of histidine, sodium carboxymethyl cellulose, calcium stearate, rumen-protected fat powder, and ethyl cellulose is 50:0.9:0.1:48.5:0.5, 40:0.9:0.1:48.5:0.5, or 40-50:0.9:0.1:48.5:0.5.

[0014] According to an embodiment of the present invention, the rumen-protected histidine composition comprises the following components: histidine, binder, and coating material; The histidine is histidine that has been pulverized; preferably, the particle size of the histidine is 100-120 mesh. The adhesive comprises sodium carboxymethyl cellulose and calcium stearate; preferably, the mass ratio of sodium carboxymethyl cellulose and calcium stearate is 8-10:0-2. The coating material comprises: rumen-protected fat powder and ethyl cellulose; preferably, the mass ratio of rumen-protected fat powder to ethyl cellulose is 47-48.8:0.2-2.0, more preferably 47.5-48.5:0.5-1.5; Preferably, the mass ratio of histidine, adhesive, and coating material is 30-60:0.1-3:40-60; more preferably, the mass ratio of histidine, adhesive, and coating material is 32-55:0.5-2:45-55, and even more preferably, 35-52:0.8-1.5:45-52.

[0015] According to an embodiment of the present invention, the rumen-protected histidine composition comprises the following components: histidine, binder, and coating material; The histidine is histidine that has been pulverized, and the particle size of the histidine is 120 mesh; The adhesive comprises sodium carboxymethyl cellulose and calcium stearate; the mass ratio of sodium carboxymethyl cellulose and calcium stearate is 9:1. The coating material comprises: rumen-protected fat powder and ethyl cellulose; the mass ratio of rumen-protected fat powder to ethyl cellulose is 48.5:0.5. Preferably, the mass ratio of histidine, adhesive, and coating material is 32-55:0.5-2:45-55.

[0016] The present invention also provides a method for preparing the above-mentioned rumen-protected histidine composition, the method comprising the following steps: (1) Histidine is pulverized; (2) Mix the pulverized histidine with the binder to prepare the core and granulate; (3) The particles prepared in step (2) are shot blasted to obtain shot blasted histidine particles; (4) The histidine particles prepared in step (3) after shot blasting are dried and sieved. (5) The particles obtained in step (4) are coated with a coating material to obtain the rumen histidine composition.

[0017] According to an embodiment of the present invention, in step (1), the particle size of histidine is 100-120 mesh, for example, 100 mesh or 120 mesh; according to an embodiment of the present invention, the size of the fine particles of histidine after pulverization is greater than 125 μm. According to an embodiment of the present invention, in step (1), a pulverizer can be used for pulverization; preferably, the pulverizer screen mesh is 100-120 mesh; preferably, the feed rate is 5 kg / min; preferably, the pulverized particle size requires that the material on the 120 mesh sieve is ≤3%, for example, 2% or 1%.

[0018] According to an embodiment of the present invention, in step (2), mixing is carried out in a high-speed shear granulator; preferably, the mixing parameters are: stirring speed 80 r / min and mixing time 10 min. According to an embodiment of the present invention, in step (2), after mixing, water is added, and then the core is prepared; preferably, the ratio of the amount of water added to the sum of the mass of histidine and binder is 1-10 L: 60 kg, for example 5 L: 60 kg; preferably, the core-encapsulation parameters are: stirring speed 300 r / min, shearing speed 2500 r / min, and mixing time 15 min.

[0019] According to an embodiment of the present invention, in step (2), after preparing the core, a rotary granulator is used for granulation; preferably, the particles are obtained through a sieve; preferably, the particles are wet particles; preferably, the sieve aperture is 2.00 mm (10 mesh); preferably, 10 mesh undersize and 40 mesh oversize are selected.

[0020] According to an embodiment of the present invention, in step (3), the particles prepared in step (2) are shot blasted using a shot blasting machine; preferably, the shot blasting process parameters are: 20 kg shot per batch, 180 r / min turntable speed, 60 s shot blasting time, and 2800 r / min blower speed. Shot blasting yields histidine particles with a relatively high specific gravity and good density.

[0021] According to an embodiment of the present invention, in step (4), the histidine particles prepared in step (3) after shot blasting are dried using a dryer; preferably, the drying process parameters are: inlet air temperature 80℃, moisture content <1%, outlet air temperature ≥50℃, and induced draft frequency 30~50 Hz. According to an embodiment of the present invention, in step (4), the dried histidine particles are sieved; preferably, the upper layer of the sieve is 10 mesh and the lower layer is 40 mesh; preferably, the outlet of the upper sieve is sealed during the sieving process.

[0022] According to an embodiment of the present invention, in step (5), the particles obtained in step (4) are coated using a bottom-spray fluidized bed; preferably, the coating material is pre-melted, and the melting temperature is preferably 80-100°C.

[0023] According to an embodiment of the present invention, in step (5), the bottom-jet fluidized bed process parameters are: The initial induced draft frequency is 25-30 Hz; Initial air intake temperature: 55-58℃; The airflow frequency during the coating process is 27-40Hz.

[0024] According to an embodiment of the present invention, in step (5), the material temperature is controlled as follows: when the ambient temperature is <26 ℃, the initial temperature is 37 ℃, and the temperature is controlled at 37-48 ℃ during the coating process; when the ambient temperature is ≥26 ℃, the initial temperature is ≥35 ℃, and the temperature is controlled at 35-48 ℃ during the coating process. According to an embodiment of the present invention, in step (5), the compressed air temperature is controlled as follows: when the ambient temperature is <26℃, 110-150℃; when the ambient temperature is ≥26℃, 70-110℃.

[0025] According to an embodiment of the present invention, in step (5), the coating liquid delivery speed is: initially 50 Hz for 30s-1min, and then adjusted to 17-18 Hz.

[0026] According to an embodiment of the present invention, the preparation method includes the following steps: (1) The histidine raw material was crushed using a pulverizer with a screen mesh of 120 mesh. The feeding speed was controlled at 5 kg / min during the crushing process. (2) Weigh histidine and binder, and mix them evenly in a high-speed shear granulator; after mixing evenly, add 5L of water to each batch of production and continue to mix evenly to prepare the core; put the core into a rotary granulator and pass it through a sieve under the action of external force to obtain wet granules with a sieve aperture of 2.00mm; select the material under 10 mesh sieve and the material over 40 mesh sieve. (3) The wet particles are put into a shot blasting machine for shot blasting to obtain histidine particles with a larger specific gravity and better density; (4) Add the shot-blasted histidine particles to a dryer for drying; sieve the dried particles and take qualified particles as core material. The sieve should be 10 mesh for the upper layer and 40 mesh for the lower layer. (5) Melt the coating material; use a bottom spray fluidized bed to coat the particles obtained in step (4).

[0027] The present invention also provides the application of the above-mentioned rumen-protected histidine composition and the rumen-protected histidine composition prepared by the above preparation method in the preparation of ruminant feed or feed additives.

[0028] The present invention also provides a method for improving the production performance of lactating cows, the method comprising administering the above-mentioned rumen-protected histidine composition or the rumen-protected histidine composition prepared by the above-mentioned preparation method to the lactating cows.

[0029] According to an embodiment of the present invention, the daily addition amount of the rumen-protected histidine is 20g.

[0030] Beneficial effects This invention provides a method for preparing rumen-protected histidine and its application. The rumen-protected histidine product obtained by this method has a higher content, a higher product qualification rate, and a better small intestinal release rate. Detailed Implementation

[0031] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0032] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0033] Rumen-protected fat powder was purchased from Nantong Kaita Chemical Technology Co., Ltd.

[0034]

[0035] Example 1: Preparation of rumen-protected histidine 1) Crush the histidine raw material (histidine purity is 80%) using a pulverizer with a 120 mesh screen. Control the feeding speed during the crushing process (about 5 kg / min) to ensure that the particle size meets the requirement of ≤3% of the material on the 120 mesh screen.

[0036] 2) According to the formula, weigh 50 kg of histidine and 10 kg of binder (9 kg of sodium carboxymethyl cellulose and 1 kg of calcium stearate) powder, and then mix them evenly in a high-speed shear granulator; powder mixing parameters: stirring speed 80 r / min, mixing time 10 min. After even mixing, add 5 L of water to each batch and continue mixing evenly to prepare the core; core preparation parameters: stirring speed 300 r / min, shearing speed 2500 r / min, mixing time 15 min. Put the core into a rotary granulator, and under external force, pass it through a sieve to obtain wet granules. The sieve aperture should be 2.00 mm (10 mesh). Select the material under the 10 mesh sieve and the material over the 40 mesh sieve. The core raw material formula is 500 kg of histidine (net histidine content is 80%), 9 kg of sodium carboxymethyl cellulose, and 1 kg of calcium stearate.

[0037] 3) The wet granules are fed into a shot blasting machine for shot blasting to obtain micro-shots with a relatively high specific gravity and good density. Process parameters: 20kg per batch, turntable speed 180r / min, shot blasting time 60s, blower speed 2800r / min. The state of the granules after shot blasting should be observed continuously during the process.

[0038] 4) Add the shot-blasted histidine granules to a dryer for drying. Process parameters: inlet air temperature 80℃, moisture content <1%, outlet air temperature ≥50℃, induced draft frequency 30~50 Hz. Sieve the dried granules, and use the qualified granules as core material. The sieve mesh should be 10 mesh for the upper layer and 40 mesh for the lower layer. Seal the outlet of the upper sieve during sieving to prevent excessive material buildup due to rapid feeding. Collect both the oversize and undersize materials for subsequent granulation processing.

[0039] 5) The coating materials are rumen-protected fat powder and ethyl cellulose, which are melted in a centralized melting tank at a controlled temperature of 80-100℃. A bottom-spray fluidized bed granulation and coating machine is used to coat the histidine core material, with a mass ratio of histidine core-coated particles to rumen-protected fat powder and ethyl cellulose of 51:48.5:0.5. The bottom-spray fluidized bed produces 200 kg per batch, yielding rumen-protected histidine.

[0040] The process parameters of the bottom-spray fluidized bed in the coating process are shown in Table 1 below.

[0041] Table 1. Process parameters of bottom-spray fluidized bed in coating process

[0042] After coating, fluidize for another 1-2 minutes depending on the material's condition to ensure complete fluidization and dispersion before stopping the machine. The coating time is calculated from the start of feeding until all material in one batch is sprayed, with an error margin of no more than 1 minute. During the coating process, the bottom of the coating pan needs to be cleaned after every 4 batches. The coated product is then sieved through an 8-mesh single-layer sieve and packaged into 25kg bags.

[0043] The contents of each component in the above-mentioned rumen-protected histidine are as follows: histidine 50: sodium carboxymethyl cellulose 0.9: calcium stearate 0.1, rumen-protected fat powder 48.5, ethyl cellulose 0.5 (histidine 500kg: sodium carboxymethyl cellulose 9kg: calcium stearate 1kg, rumen-protected fat powder 485 kg, ethyl cellulose 5 kg).

[0044] Example 2: Study on particle size of histidine raw material The core containing histidine and binder was prepared according to steps 1) and 2) of Example 1. The main difference is that the histidine raw material in step 1) is not pulverized (Example 2-1). The feed-grade histidine has a particle size of 80 mesh and is a crystalline structure.

[0045] The results showed that histidine raw material, without being pulverized, did not readily form a core when mixed with the binder in step 2). The crystalline amino acid exhibited a larger coefficient of variation, requiring a longer mixing time.

[0046] Further research was conducted on the effect of different particle sizes on the yield of core-coated particles, and the results are shown in Table 2 below. The study found that a histidine particle size of 120 mesh resulted in the optimal yield of core-coated particles, shorter mixing time, and lower coefficient of variation, providing a basis for producing higher effective coating amounts.

[0047] Table 2 Study on particle size of histidine raw material

[0048] Coefficient of variation (CV): CV = S / X × 100%, the ratio of standard deviation to mean, usually expressed as a percentage, is the most commonly used statistic for assessing the homogeneity of a mixture. S: Standard deviation of the target component content in the sample; X: Arithmetic mean of the target component content in the sample.

[0049] Example 3: Research on Adhesives Wet granules were prepared according to steps 1) and 2) of Example 1, the main difference being the different binder in step 2). After obtaining the pulverized histidine raw material according to step 1), 50 kg of histidine and different binder powders (the composition of the binder is shown in Table 3) were weighed and then mixed evenly in a high-speed shear granulator; the powder mixing parameters were: stirring speed 80 r / min, mixing time 10 min. After even mixing, 5 L of water was added to each batch of production, and the mixture was further mixed evenly to prepare the core; the core preparation parameters were: stirring speed 300 r / min, shearing speed 2500 r / min, mixing time 15 min. The core was fed into a rotary granulator, and wet granules were obtained by passing the core through a sieve under external force. The maximum required sieve aperture was 2.00 mm (10 mesh), and the material passing through the 10 mesh sieve and the material passing through the 40 mesh sieve were selected.

[0050] Table 3 shows that in Example 3-1, the granulation qualification rate of 50 kg histidine and binder was 61%, while the 7 kg carboxymethyl cellulose had limited bonding strength and was easily broken into small particles in the rotary granulator, resulting in a high 40-mesh pass rate. In Example 3-2, the granulation qualification rate of 50 kg histidine and binder was 85%, with improved bonding strength and a reduced proportion of small particles. In Example 3-3, the granulation qualification rate of 50 kg histidine and binder was 95%, with strong bonding strength and anti-caking ability. In Example 3-4, the granulation qualification rate of 50 kg histidine and binder was 82%, with strong bonding strength but no anti-caking ability, and a high proportion of large particles easily agglomerated.

[0051] Table 3. Research on adhesives

[0052] Example 4: Study on Coating Process Rumen-protected histidine was prepared according to Example 1, with the main difference being the coating material in step 5). After obtaining the histidine core-coated material according to steps 1)-4), the rumen-protected fat powder and ethyl cellulose were melted in a centralized melting tank at a controlled temperature of 80-100℃. The histidine core-coated material was coated using a bottom-spray fluidized bed granulation and coating machine. The mass ratio of histidine core-coated particles to rumen-protected fat powder and ethyl cellulose is shown in Table 4. Each batch of bottom-spray fluidized bed produced 200 kg of rumen-protected histidine.

[0053] The rumen degradation rate and 16-hour simulated small intestinal release rate of histidine obtained by different coating processes were detected using a dissolution analyzer. The results are shown in Table 5-6.

[0054] Rumen degradation rate detection method: Four Holstein lactating cows with permanent rumen fistulas were selected as experimental animals. The rumen degradation rate of histidine in the rumen was determined at six culture points (2 hours, 4 hours, 8 hours, 12 hours, 16 hours, and 24 hours) using the rumen nylon bag method (semi-in vivo method). Samples were placed in the rumen for degradation. After rumen degradation, the sample bags were removed at different time points, cleaned with running water, dried in a 50℃ drying oven, and weighed. The content of the sample in each nylon bag was determined, and its degradation rate was calculated. Rumen degradation rate (%) = 100 × (content of a nutrient before degradation - content of a nutrient after degradation) / content of a nutrient before degradation.

[0055] Simulated small intestinal release rate detection method: The sample cultured in the rumen for 16 h was placed in a nylon bag with a pore size of 40 μm and a length × width of 3 cm × 6 cm and electrically sealed. Three bags were placed in each culture flask, and pepsin hydrochloride solution was added and shaken in a 39℃ water bath for 1 h. After incubation, the liquid was poured off, the bags were rinsed clean with tap water, and preheated trypsin solution was added to the culture flask. After shaking and incubation at 39℃ for 24 h, the bags were rinsed clean, dried, and placed in sample bottles to test the histidine content.

[0056] Table 4 Research on coating technology

[0057] Table 5. Results of rumen degradation rate of histidine after rumen passage.

[0058] Table 6 Results of 16-hour simulated small intestinal release rate detection

[0059] Table 7 shows the effective histidine content in the small intestine per kilogram of coated histidine ingested. Effective histidine utilization = (rumen degradation rate at 1-16h) * small intestinal release rate at 16h * net histidine content in the core (40%). Table 7. Effective histidine content in the small intestine

[0060] As shown in Tables 5-7, Examples 4-3 have better rumen passage rate and small intestinal release rate, ensuring an effective histidine content of 333.50g in the small intestine.

[0061] Example 5: Effects of rumen-protected histidine on lactating cow performance 1. Materials and Methods 1.1 Selection, grouping, and feeding management of experimental dairy cows Three hundred and twenty Holstein early-lactation dairy cows with an average lactation period of 48 days, parity of 2.8, and similar milk yield and body condition were randomly divided into two groups of 160 cows each. The control group received no supplemental feed (basal diet), while the experimental group received 20g of rumen-protected histidine per cow per day in their basal diet (Example 1). During the experiment, the cows were fed and managed according to standard farm procedures, with three feedings (morning, noon, and evening) and three milkings per day. The experiment lasted for 30 days.

[0062] 1.2 Detection Indicators Milk production and milk composition were recorded. The total daily milk production was exported from the milk collection station's statistical software. Fresh milk of 50 mL was collected from individual milk tanks in a 4:3:3 ratio for morning, noon, and evening for milk composition detection and analysis using a Milkoscan milk composition analyzer.

[0063] 1.3 Data Processing Data on milk yield and milk composition were analyzed using SPSS 22.0 software and ANOVN (one-way ANOVA). The results are expressed as mean ± standard deviation.

[0064] 2. Results and Analysis 2.1 Effects of rumen-protected histidine on the production performance of lactating dairy cows according to the present invention Table 8. Effects of rumen-protected histidine on the production performance of lactating dairy cows.

[0065] Note: Lowercase letters (a, b) above the data in the same row indicate significant differences (p < 0.05), while the same letters or no label indicates no significant differences (p > 0.05).

[0066] As shown in Table 8, the average daily milk production of the experimental group was 2.17 kg higher than that of the control group, an increase of 4.35%, demonstrating a significant effect on increasing milk production (p < 0.05). The milk protein content of the experimental group was 6.33% higher than that of the control group (p < 0.05).

[0067] 3. Conclusion Adding 20g of rumen-protected histidine to the diet of lactating dairy cows can significantly increase milk yield and milk protein content, thereby improving the economic benefits of the farm.

[0068] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rumen-protected histidine composition, wherein the histidine content or mass ratio is 30%-60%; Preferably, the content or mass ratio of histidine is 32%-55%.

2. The rumen-protected histidine composition according to claim 1, characterized in that, The rumen-protected histidine composition further comprises a binder; preferably, the content or mass ratio of the binder is 0.1%-3% or 0.2%-2.0%. Preferably, the rumen-protected histidine composition further comprises a coating material; preferably, the content or mass ratio of the coating material is 40%-60% or 42%-58%.

3. The rumen-protected histidine composition according to claim 1 or 2, characterized in that, The rumen-protected histidine composition comprises the following components: histidine, binder, and coating material; Preferably, the mass ratio of histidine, binder, and coating material is 30-60:0.1-3:40-60; Preferably, the mass ratio of histidine, binder, and coating material is 32-55:0.5-2:45-55, more preferably 35-52:0.8-1.5:45-52, for example 50:1:49, 40:1:49, or 40-50:1:

49.

4. The rumen-protected histidine composition according to any one of claims 1-3, characterized in that, The histidine is histidine that has been pulverized; preferably, the particle size of the histidine is 100-120 mesh; preferably, the size of the fine particles of the pulverized histidine is greater than 125 μm.

5. The rumen-protected histidine composition according to any one of claims 2-4, characterized in that, The adhesive is selected from sodium carboxymethyl cellulose, or a combination of sodium carboxymethyl cellulose and calcium stearate; preferably, the adhesive comprises sodium carboxymethyl cellulose and calcium stearate; preferably, the mass ratio of sodium carboxymethyl cellulose to calcium stearate is 8-10:0-2. Preferably, the coating material comprises: rumen-protected fat powder and ethyl cellulose; preferably, the mass ratio of rumen-protected fat powder to ethyl cellulose is 47-48.8:0.2-2.0, more preferably 47.5-48.5:0.5-1.

5. Preferably, the mass ratio of histidine, binder, rumen-protected fat powder, and ethyl cellulose is 50:1:48.5:0.5, 40:1:48.5:0.5, or 40-50:1:48.5:0.

5. Preferably, the mass ratio of histidine, sodium carboxymethyl cellulose, calcium stearate, rumen-protected fat powder, and ethyl cellulose is 50:0.9:0.1:48.5:0.5, 40:0.9:0.1:48.5:0.5, or 40-50:0.9:0.1:48.5:0.

5.

6. The rumen-protected histidine composition according to any one of claims 2-5, characterized in that, The rumen-protected histidine composition comprises the following components: histidine, binder, and coating material; The histidine is histidine that has been pulverized; preferably, the particle size of the histidine is 100-120 mesh. The adhesive comprises sodium carboxymethyl cellulose and calcium stearate; preferably, the mass ratio of sodium carboxymethyl cellulose and calcium stearate is 8-10:0-2. The coating material includes: rumen-protected fat powder and ethyl cellulose; preferably, the mass ratio of rumen-protected fat powder to ethyl cellulose is 47-48.8:0.2-2.0, more preferably 47.5-48.5:0.5-1.5; Preferably, the mass ratio of histidine, binder, and coating material is 30-60:0.1-3:40-60; Preferably, the rumen-protected histidine composition comprises the following components: histidine, binder, and coating material; the histidine is pulverized histidine with a particle size of 120 mesh; the binder comprises sodium carboxymethyl cellulose and calcium stearate; the mass ratio of sodium carboxymethyl cellulose and calcium stearate is 9:1; the coating material comprises: rumen-protected fat powder and ethyl cellulose; the mass ratio of rumen-protected fat powder to ethyl cellulose is 48.5:0.5; preferably, the mass ratio of histidine, binder, and coating material is 32-55:0.5-2:45-55.

7. A method for preparing the rumen-protected histidine composition according to any one of claims 1-6, the method comprising the following steps: (1) Histidine is pulverized; (2) Mix the pulverized histidine with the binder to prepare the core and granulate; (3) The particles prepared in step (2) are shot blasted to obtain shot blasted histidine particles; (4) The histidine particles prepared in step (3) after shot blasting are dried and sieved. (5) The particles obtained in step (4) are coated with a coating material to obtain the rumen histidine composition.

8. The preparation method according to claim 7, characterized in that, In step (1), the particle size of histidine is 100-120 mesh, for example, 100 mesh or 120 mesh; preferably, the size of the fine particles of histidine after pulverization is greater than 125 μm; preferably, in step (1), a pulverizer can be used for pulverization; preferably, the pulverizer screen mesh is 100-120 mesh; preferably, the feed rate is 5 kg / min; preferably, the pulverized particle size requirement is that the material on the 120 mesh sieve is ≤3%, for example, 2% or 1%; And / or, in step (2), mixing is carried out in a high-speed shear granulator; preferably, the mixing parameters are: stirring speed 80 r / min, mixing time 10 min; preferably, in step (2), after mixing, water is added, and then the core is prepared; preferably, the ratio of the amount of water added to the sum of the mass of histidine and binder is 1-10 L: 60 kg, for example 5 L: 60 kg; preferably, the core-encapsulation parameters are: stirring speed 300 r / min, shearing speed 2500 r / min, mixing time 15 min; And / or, in step (2), after preparing the core, granulation is performed using a rotary granulator; preferably, the particles are obtained through a sieve; preferably, the particles are wet particles; preferably, the sieve aperture is 2.00 mm (10 mesh); preferably, 10 mesh undersize and 40 mesh oversize are selected; And / or, in step (3), the particles prepared in step (2) are shot blasted using a shot blasting machine; preferably, the shot blasting process parameters are: 20kg shot per batch, 180r / min turntable speed, 60s shot blasting time, and 2800r / min blower speed. And / or, in step (4), the histidine particles prepared in step (3) after shot blasting are dried using a dryer; preferably, the drying process parameters are: inlet air temperature 80℃, moisture content <1%, outlet air temperature ≥50℃, and induced draft frequency 30~50HZ; preferably, in step (4), the dried histidine particles are sieved; preferably, the upper layer of the sieve is 10 mesh and the lower layer is 40 mesh; preferably, the outlet of the upper sieve is sealed during the sieving process; And / or, in step (5), the particles obtained in step (4) are coated using a bottom-spray fluidized bed; preferably, the coating material is pre-melted at a melting temperature of 80-100℃; preferably, in step (5), the bottom-spray fluidized bed process parameters are: initial induced draft frequency 25-30 Hz; initial inlet air temperature 55-58 ℃; induced draft frequency during coating process 27-40 Hz; preferably, in step (5), the material temperature is controlled as follows: when the ambient temperature is <26 ℃, the initial temperature is 37 ℃, and the temperature is controlled at 37-48 ℃ during coating process; when the ambient temperature is ≥26 ℃, the initial temperature is ≥35 ℃, and the temperature is controlled at 35-48 ℃ during coating process; preferably, in step (5), the compressed air temperature is controlled as follows: when the ambient temperature is <26 ℃, the temperature is 110-150 ℃; when the ambient temperature is ≥26 ℃, the temperature is 70-110 ℃; preferably, in step (5), the coating liquid conveying speed is: initially 50 The frequency was transmitted for 30 seconds to 1 minute, and then adjusted to 17-18 Hz.

9. The use of the rumen-protected histidine composition according to any one of claims 1-6, and the rumen-protected histidine composition prepared by the preparation method according to any one of claims 7-8, in the preparation of ruminant feed or feed additives.

10. A method for improving the production performance of lactating cows, the method comprising administering to the lactating cows the rumen-protected histidine composition according to any one of claims 1-6, or the rumen-protected histidine composition prepared by the preparation method according to any one of claims 7-8; Preferably, the daily addition amount of the rumen-protected histidine is 20g.

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