Feed additive for improving digestion efficiency of rumen of livestock and preparation method of feed additive

Abstract

The invention discloses a feed additive for improving digestion efficiency of rumen of livestock and a preparation method of the feed additive, and belongs to the technical field of animal feed additives, the surface of nanometer magnesium oxide is intercalated in bentonite particles, and the nanometer magnesium oxide is used as the feed additive to facilitate food absorption and improve digestion efficiency; urea is adsorbed in zeolite, and hydroxyl on the surface and carboxyl of an acrylic acid solution are subjected to an esterification reaction, so that a spatial network structure of a starch grafted modified acrylic acid solution and a protein supplement is formed, and slow release of urea is further enhanced; compound amino acid particles are coated in a spatial network structure of a starch-grafted modified acrylic acid solution and a protein supplement, so that degradation of amino acid in rumen is reduced, full absorption of the amino acid by small intestines is promoted, the utilization rate of the amino acid is increased, and growth of rumen microorganisms is promoted; the zeolite and the bentonite can cooperate with the adsorption effect of the starch grafted modified acrylic acid solution resin, so that the emission of ammonia gas is reduced, and the feeding environment is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of animal feed additives, and in particular relates to a feed additive for improving livestock rumen digestion efficiency and a preparation method thereof. Background Art

[0002] Rumination refers to the process of returning semi-digested food in the stomach to the mouth for re-chewing after a period of time. The stomach of ruminants is usually divided into four stomach chambers (camels have three stomach chambers), namely the rumen, reticulum, omasum and abomasum. Food is regurgitated, chewed slowly to fully mix, further decompose the fiber, and then swallowed again. It passes through the rumen to the omasum for dehydration, and then sent to the abomasum, and finally sent to the small intestine for absorption. Existing ruminant feeds are usually made of crop straw as the main raw material, but the lignin, cellulose and hemicellulose cells contained in the straw are "coated" by lignin, which hinders the decomposition of enzymes, and lignin itself cannot be digested, making it difficult for animals to digest and absorb after feeding on straw, thereby reducing the nutritional value of existing feeds and failing to meet the nutritional needs of ruminants.

[0003] The degradation and utilization rate of nitrogen-containing substances in the digestive tract of ruminants is inconsistent with the degradation rate of energy carrier substances in the digestive tract, which will cause the degradation of energy carrier substances and nitrogen sources given to rumen microorganisms to be inconsistent or asynchronous in the short term. A Chinese patent with announcement number CN106343182B announces a feed additive for reducing nitrogen excretion in ruminants and a preparation method thereof. The method comprises spraying acrylic acid solution resin on the surface of feed-grade urea, drying it, and then coating it with pregelatinized starch solution. The coating layer is mainly formed by physical adhesion, and the bonding strength is relatively low, and a stable and long-term sustained-release effect cannot be achieved. Summary of the invention

[0004] The purpose of the present invention is to provide a feed additive for improving the digestion efficiency of livestock rumen and a preparation method thereof. The surface of nano magnesium oxide is intercalated in bentonite particles, which is used as a feed additive to help promote food absorption and improve digestion efficiency. Urea is adsorbed in zeolite, and esterification reaction occurs between the surface hydroxyl group and the carboxyl group of the acrylic acid solution to form a spatial network structure of starch grafted modified acrylic acid solution and protein supplement, further enhancing the sustained release effect of urea.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a feed additive for improving livestock rumen digestion efficiency comprises the following steps:

[0007] Step 1: Add acrylic acid solution with a neutralization degree of 40 - 50% and deionized water into a reaction kettle and stir to mix. Adsorb urea onto zeolite powder to prepare a protein supplement, and then add the protein supplement and gelatinized starch solution into the reaction kettle. Stir at 55 - 60 °C and 400 - 500 r / min for 1.5 - 2 h. Add sodium sulfite and hydroxymethylacrylamide into the reaction kettle, and stir at 60 - 75 °C and 400 - 550 r / min for 2 - 3 h. Filter, wash the filter cake with deionized water and absolute ethanol respectively for 2 - 3 times, and dry it under vacuum to obtain a composite nutrient slow-release agent;

[0008] Step 2: Intercalate nano-magnesium oxide in bentonite particles to prepare a digestive aid. Then add the digestive aid, composite nutrient slow-release agent, composite amino acid particles and microbial agent into a blender according to the mass ratio of 25:50:15:5 and mix evenly. Place it in a feed granulator to granulate and obtain a feed additive for improving the rumen digestion efficiency of livestock.

[0009] Furthermore, in Step 1, the dosage ratio of acrylic acid solution, deionized water, protein supplement, gelatinized starch solution, sodium sulfite and hydroxymethylacrylamide is 200 - 300 mL:400 - 500 mL:15 - 18 g:180 - 200 mL:0.5 - 0.7 g:0.3 - 0.5 g.

[0010] Furthermore, the composite amino acid particles in Step 2 are prepared by dry granulation from carboxymethyl cellulose, cysteine and methionine according to the mass ratio of 20 - 30 g:4 - 5 g:5 - 6 g.

[0011] Furthermore, the microbial agent is any one or more of Bacillus subtilis, lactic acid bacteria and ruminant yeast in any mass ratio combination.

[0012] Furthermore, the gelatinized starch solution is prepared through the following steps:

[0013] Add starch and deionized water into a reaction kettle. Under a nitrogen atmosphere, carry out a gelatinization reaction at 80 - 90 °C and 500 - 600 r / min for 30 - 40 min, and cool to 55 - 65 °C to obtain a gelatinized starch solution.

[0014] Furthermore, the dosage ratio of starch and deionized water is 20 - 30 g:200 - 300 mL.

[0015] Furthermore, the specific preparation steps of the protein supplement are as follows:

[0016] Add zeolite powder with a particle size of 4 - 5 mm, dimethyl sulfoxide, and cetyltrimethylammonium bromide into a reaction kettle, stir for 1 - 2 h under the conditions of 50 - 60 °C and 500 - 600 r / min. Dissolve urea in absolute ethanol and drop it into the reaction kettle, continue to stir for 4 - 5 h, age at 65 - 70 °C for 24 - 26 h, centrifuge and wash the product with deionized water 2 - 3 times, and vacuum dry at 60 - 80 °C for 1 - 2 h to obtain a protein supplement.

[0017] Furthermore, the dosage ratio of zeolite powder, dimethyl sulfoxide, cetyltrimethylammonium bromide, urea, and absolute ethanol is 20 - 30 g : 200 - 300 mL : 2 - 3 g : 30 - 50 g : 400 - 500 mL.

[0018] Furthermore, the specific preparation steps of the digestive aid are as follows:

[0019] Add bentonite with a particle size of 2 - 3 μm and absolute ethanol into a reaction kettle, stir and mix them, then add glacial acetic acid and a nitric acid solution with a concentration of 0.5 - 0.6 mol / L, stir and react for 1 - 2 h under the conditions of 20 - 25 °C and 800 - 900 r / min, dropwise add a NaOH solution with a concentration of 0.8 - 0.9 mol / L, age at 65 - 70 °C for 24 - 26 h, ultrasonically disperse nano - magnesium oxide with a particle size of 50 - 60 nm in deionized water and add it into the reaction kettle, continue to stir for 40 - 50 min, age at 65 - 70 °C for 24 - 26 h, centrifuge and wash the product with deionized water 2 - 3 times, and vacuum dry at 60 - 80 °C for 1 - 2 h to obtain a digestive aid.

[0020] Furthermore, the dosage ratio of bentonite, absolute ethanol, glacial acetic acid, nitric acid solution, NaOH solution, nano - magnesium oxide, and deionized water is 20 - 30 g : 400 - 500 mL : 8 - 10 mL : 2 - 3 mL : 1 - 2 mL : 40 - 50 g : 500 - 600 mL.

[0021] The beneficial effects of the present invention:

[0022] 1. A feed additive for improving the rumen digestion efficiency of livestock prepared by the present invention is beneficial to digestion, improves the utilization rate of amino acids, and slows down the loss of urea nitrogen.

[0023] 2. The surface of the nano-magnesium oxide of the present invention is negatively charged and forms a bond with the cations on the surface of bentonite particles, thereby strengthening the structural stability of bentonite and enabling it to be uniformly intercalated in bentonite. Nano-magnesium oxide can promote the dispersion of bentonite particles, making the components in the feed more uniform, which helps to improve the uniformity and mixability of the feed, ensuring that animals can obtain balanced nutrition when ingesting the feed. Moreover, nano-magnesium oxide is an alkaline substance, and by intercalating in bentonite, it can better neutralize gastric acid, promote the digestion and absorption of food, and improve the digestion efficiency.

[0024] 3. The protein supplement of the present invention can be used as a nitrogen source to provide the required nitrogen element for animals. Zeolite has excellent adsorption performance and cation exchange performance, which can slow down the loss of urea nitrogen. In the spatial network structure of the protein supplement and the starch-grafted modified acrylic acid solution, the loss of urea nitrogen is further slowed down, and the conversion rate of urea nitrogen to NH 4 + -N is reduced, and the synthesis rate of rumen microbial protein is increased; when urea decomposes in the animal body, ammonia gas is generated, and zeolite and bentonite can cooperate with the adsorption of the starch-grafted modified acrylic acid solution resin to reduce ammonia emissions and reduce the odor in the environment.

[0025] 4. The protein supplement can undergo an esterification reaction between the hydroxyl groups on its surface and the carboxyl groups of the acrylic acid solution to form a spatial network structure of the starch-grafted modified acrylic acid solution and the protein supplement, further enhancing the slow release of urea. And by encapsulating the composite amino acid particles in the spatial network structure of the starch-grafted modified acrylic acid solution and the protein supplement, using the combined adsorption of the resin and zeolite, the degradation of amino acids in the rumen is reduced, promoting the full absorption of amino acids by the small intestine, thereby improving the utilization rate of amino acids and promoting the growth of rumen microorganisms. Detailed implementation mode

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] Example 1: A preparation method of a feed additive for improving the rumen digestion efficiency of livestock, including the following steps:

[0028] S1: Add 20 g of bentonite with a particle size of 2 - 3 μm and 400 mL of absolute ethanol into a reaction kettle, stir and mix them, then add 8 mL of glacial acetic acid and 2 mL of nitric acid solution with a concentration of 0.5 mol / L. Stir and react for 1 h under the conditions of 20 °C and 800 r / min. Dropwise add 1 mL of NaOH solution with a concentration of 0.8 mol / L, and age at 65 °C for 24 h. Ultrasonically disperse 40 g of nano-magnesium oxide with a particle size of 50 - 60 nm in 500 mL of deionized water and add it into the reaction kettle, continue to stir for 40 min, and age at 65 °C for 24 h. Centrifuge and wash the product with deionized water 3 times, and vacuum dry at 60 °C for 1 h to obtain a digestive aid.

[0029] The surface of nano-magnesium oxide is negatively charged, which can adsorb water molecules and form bond compounds with the cations on the surface of bentonite particles. Through intercalation, the layer spacing of bentonite is increased, thereby improving its adsorption performance and enhancing the structural stability of bentonite. Nano-magnesium oxide can also promote the dispersion of bentonite particles, making the components in the feed more uniform, which helps to improve the uniformity and mixability of the feed, ensuring that animals can obtain balanced nutrition when ingesting the feed. Nano-magnesium oxide is an alkaline substance that can neutralize gastric acid, promote the digestion and absorption of food. Nano-magnesium oxide can stimulate intestinal peristalsis, help the propulsion and digestion of food in the intestine, and improve the digestion efficiency.

[0030] S2: Add 20 g of zeolite powder with a particle size of 4 - 5 mm, 200 mL of dimethyl sulfoxide and 2 g of cetyltrimethylammonium bromide into a reaction kettle, stir at 50 °C and 500 r / min for 1 h. Dissolve 30 g of urea in 400 mL of absolute ethanol and dropwise add it to the reaction kettle, continue to stir for 4 h, age at 65 °C for 24 h. Centrifuge and wash the product with deionized water 3 times, and vacuum dry at 60 °C for 1 h to obtain a protein supplement.

[0031] The protein supplement can be used as a nitrogen source to provide the required nitrogen element for animals. Zeolite has excellent adsorption performance and cation exchange performance, which can slow down the loss of urea nitrogen and the conversion rate of urea nitrogen to NH 4 + -N; When urea decomposes in animals, ammonia gas will be produced, and the adsorption of zeolite can reduce the emission of ammonia gas and reduce the odor in the environment.

[0032] S3: Add 20 g of starch and 200 mL of deionized water into a reaction kettle. Under a nitrogen atmosphere, carry out a gelatinization reaction at 80 °C and 500 r / min for 30 min, and then cool it to 55 °C to obtain a gelatinized starch solution. Add 200 mL of acrylic acid solution with a neutralization degree of 40% and 400 mL of deionized water into the reaction kettle, add 15 g of protein supplement and 180 mL of gelatinized starch solution into the reaction kettle, stir at 55 °C and 400 r / min for 1.5 - 2 h, add 0.5 g of sodium sulfite as an initiator and 0.3 g of hydroxymethylacrylamide as a crosslinking agent into the reaction kettle, heat to 60 °C, stir at 400 r / min for 2 h, filter, wash the filter cake with deionized water and absolute ethanol twice respectively, and dry it in vacuum at 60 °C for 1 h to obtain a composite nutrient slow-release agent.

[0033] The protein supplement can undergo an esterification reaction with the carboxyl group of the acrylic acid solution through the hydroxyl groups on its surface, forming a spatial network structure of starch-grafted modified acrylic acid solution and protein supplement, realizing the coating of the resin and enhancing the slow release of urea.

[0034] S4: Prepare composite amino acid granules from 20 g of carboxymethyl cellulose, 4 g of cysteine and 5 g of methionine through a dry granulator. Add the digestive aid, composite nutrient slow-release agent, composite amino acid granules and Bacillus subtilis into a blender according to a mass ratio of 25:50:15:5, mix evenly, and granulate in a feed granulator to obtain a feed additive for improving the rumen digestion efficiency of livestock.

[0035] By encapsulating the composite amino acid granules in the spatial network structure of starch-grafted modified acrylic acid solution and protein supplement, and utilizing the adsorption of the resin and zeolite, the degradation of amino acids in the rumen is reduced, the full absorption of amino acids by the small intestine is promoted, thereby improving the utilization rate of amino acids and promoting the growth of rumen microorganisms.

[0036] Example 2: A preparation method of a feed additive for improving the rumen digestion efficiency of livestock, including the following steps:

[0037] S1: Add 25 g of bentonite with a particle size of 2 - 3 μm and 450 mL of absolute ethanol into a reaction kettle, stir and mix, then add 9 mL of glacial acetic acid and 2.3 mL of nitric acid solution with a concentration of 0.55 mol / L, stir and react at 23 °C and 850 r / min for 1.5 h, dropwise add 1.2 mL of NaOH solution with a concentration of 0.85 mol / L, age at 68 °C for 25 h, ultrasonically disperse 45 g of nano-magnesium oxide with a particle size of 50 - 60 nm in 550 mL of deionized water and add it into the reaction kettle, continue to stir for 45 min, age at 68 °C for 25 h, centrifuge and wash the product with deionized water three times, and dry it in vacuum at 70 °C for 1.2 h to obtain a digestive aid.

[0038] S2: Add 25 g of zeolite powder with a particle size of 4 - 5 mm, 250 mL of dimethyl sulfoxide, and 2.3 g of cetyltrimethylammonium bromide into a reaction kettle. Stir for 1.2 h under the conditions of 55 °C and 550 r / min. Dissolve 45 g of urea in 450 mL of absolute ethanol and drop it into the reaction kettle. Continue to stir for 4.5 h and age at 68 °C for 25 h. Centrifuge and wash the product with deionized water three times, and then vacuum dry at 70 °C for 1.2 h to obtain a protein supplement.

[0039] S3: Add 25 g of starch and 250 mL of deionized water into a reaction kettle. Under a nitrogen atmosphere, carry out a gelatinization reaction at 85 °C and 550 r / min for 35 min, and then cool to 60 °C to obtain a gelatinized starch solution; Add 250 mL of acrylic acid solution with a neutralization degree of 45% and 450 mL of deionized water into the reaction kettle. Add 17 g of the protein supplement and 190 mL of the gelatinized starch solution into the reaction kettle. Stir at 58 °C and 450 r / min for 1.8 h. Add 0.6 g of sodium sulfite as an initiator and 0.4 g of hydroxymethylacrylamide as a crosslinking agent into the reaction kettle. Heat to 70 °C and stir at 450 r / min for 2.3 h. Filter, wash the filter cake with deionized water and absolute ethanol twice respectively, and then vacuum dry at 70 °C for 1.2 h to obtain a composite nutrient slow-release agent.

[0040] S4: Crush 25 g of carboxymethyl cellulose, and use a dry granulator to prepare composite amino acid granules from 4.5 g of cysteine and 5.6 g of methionine; Add a digestive aid, a composite nutrient slow-release agent, the composite amino acid granules, and lactic acid bacteria into a blender according to a mass ratio of 25:50:15:5, mix evenly, and granulate in a feed granulator to obtain a feed additive for improving the rumen digestion efficiency of livestock.

[0041] Example 3: A preparation method of a feed additive for improving the rumen digestion efficiency of livestock, which includes the following preparation steps:

[0042] S1: Add 30 g of bentonite with a particle size of 2 - 3 μm and 500 mL of absolute ethanol into a reaction kettle, stir and mix, then add 10 mL of absolute acetic acid and 3 mL of nitric acid solution with a concentration of 0.6 mol / L. Stir and react at 25 °C and 900 r / min for 2 h. Dropwise add 2 mL of NaOH solution with a concentration of 0.9 mol / L, and age at 70 °C for 26 h. Ultrasonically disperse 50 g of nano-magnesium oxide with a particle size of 50 - 60 nm in 600 mL of deionized water and add it into the reaction kettle. Continue to stir for 50 min and age at 70 °C for 26 h. Centrifuge and wash the product with deionized water three times, and then vacuum dry at 80 °C for 2 h to obtain a digestive aid.

[0043] S2: Add 30 g of zeolite powder with a particle size of 4 - 5 mm, 300 mL of dimethyl sulfoxide, and 3 g of cetyltrimethylammonium bromide into a reaction kettle, stir for 2 h under the conditions of 60 °C and 600 r / min, dissolve 50 g of urea in 500 mL of absolute ethanol and drop it into the reaction kettle, continue to stir for 5 h, age at 70 °C for 26 h, wash the product with deionized water by centrifugation 3 times, and dry it in vacuum at 80 °C for 2 h to obtain a protein supplement.

[0044] S3: Add 30 g of starch and 300 mL of deionized water into a reaction kettle, carry out a gelatinization reaction for 40 min under the conditions of 90 °C and 600 r / min in a nitrogen atmosphere, and cool to 65 °C to obtain a gelatinized starch solution; add 300 mL of acrylic acid solution with a neutralization degree of 50% and 500 mL of deionized water into the reaction kettle, add 18 g of the protein supplement and 200 mL of the gelatinized starch solution into the reaction kettle, stir for 2 h under the conditions of 60 °C and 500 r / min, add 0.7 g of sodium sulfite as an initiator and 0.5 g of hydroxymethylacrylamide as a crosslinking agent into the reaction kettle, heat to 75 °C, stir at 550 r / min for 3 h, filter, wash the filter cake with deionized water and absolute ethanol 3 times respectively, and dry it in vacuum at 80 °C for 2 h to obtain a composite nutrient slow-release agent.

[0045] S4: Prepare composite amino acid granules from 30 g of carboxymethyl cellulose, 5 g of cysteine, and 6 g of methionine through a dry granulator; mix Bacillus subtilis, Lactobacillus, and rumen yeast in a mass ratio of 1:1:3 to obtain a microbial preparation; add the digestive aid, composite nutrient slow-release agent, composite amino acid granules, and microbial preparation into a mixer in a mass ratio of 25:50:15:5, mix evenly, and granulate in a feed granulator to obtain a feed additive for improving the rumen digestion efficiency of livestock.

[0046] In the examples, raw materials such as Bacillus subtilis, Lactobacillus, and rumen yeast are all commercially available products.

[0047] Comparative Example 1: On the basis of Example 3, according to a feed additive for reducing nitrogen excretion in ruminants and its preparation method with the publication number CN106343182B, spray the composite nutrient slow-release agent in step S3 on the surface of commercially available urea, dry it, and then coat it with the gelatinized starch solution, and keep the other steps unchanged to prepare a feed additive for improving the rumen digestion efficiency of livestock.

[0048] Comparative Example 2: On the basis of Example 3, replace the digestive aid in step S1 with a mixture of bentonite and nano-magnesium oxide with a mass ratio of 3:5, and keep the other steps unchanged to prepare a feed additive for improving the rumen digestion efficiency of livestock.

[0049] Comparative Example 3: Based on Example 3, the protein supplement in step S2 is replaced with a mixture of zeolite and urea in a mass ratio of 3:5, and the other steps remain unchanged to prepare a feed additive for improving livestock rumen digestion efficiency.

[0050] Comparative Example 4: Based on Example 3, the composite nutrient slow-release agent in step S4 is discarded, and the other steps remain unchanged to prepare a feed additive for improving livestock rumen digestion efficiency.

[0051] The reagents in the examples and comparative examples were purchased from conventional commercial sources.

[0052] The feed additives for improving the rumen digestion efficiency of livestock prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were tested for performance. The test method was as follows: the feed additives were prepared with reference to the nutritional needs of sheep in the United States NRC (1998). The nutritional levels of each group were exactly the same. The feed additives were added in strict accordance with the "Chinese Feed Additive Additive Standard". The daily feed contained the following components in percentage: 40wt% hay, 32wt% corn flour, 8wt% soybean meal, 2wt% limestone, 1wt% salt and 1wt% mineral mixture (the mineral mixture includes niacin, manganese, zinc, iron, copper, selenium, iodine, cobalt, vitamin E, vitamin D and vitamin A). The daily diets of each group were accurately weighed and placed in a mixer for mixing for 5 minutes. After sampling and testing, they were fed to the experimental animals after passing the test. The feed additives for reducing nitrogen excretion of ruminants prepared in Examples 1, 2 and 3 were fed according to conventional feeding management and immunization. They were fed at 5:00 and 17:00 every day in the order of fine first and coarse later, and drinking water was free. The results are shown in Table 1:

[0053] Table 1 Performance test table of feed additives for improving livestock rumen digestion efficiency

[0054]

[0055]

[0056] It can be seen from Table 1 that after the feed additives for improving livestock rumen digestion efficiency prepared in Examples 1 to 3 were added to feed for feeding, the stomach pH value, ammonia nitrogen content and bacterial protein concentration were significantly higher than those of the control example, and the excretion of total nitrogen was significantly lower than that of the control example, indicating that the feed additives for improving livestock rumen digestion efficiency prepared in the present invention have good digestion-promoting ability, high protein utilization efficiency and less urea nitrogen loss.

[0057] In Comparative Example 1, the composite nutrient slow-release agent was sprayed on the surface of urea, dried, and then coated with a gelatinized starch solution. The coating layer was mainly formed by physical adhesion and had relatively low bonding strength, making it easily hydrolyzed by enzymes in the rumen. Under the action of rumen urease, urea would quickly decompose into ammonia and carbon dioxide. The rate of ammonia release was much higher than the rumen absorption and utilization rate and also exceeded the fermentation rate of carbohydrates in the rumen. This would lead to the accumulation of ammonia in the rumen, potentially causing ammonia poisoning, resulting in a decrease in nitrogen content and an increase in the total nitrogen discharge.

[0058] In Comparative Example 2, the digestive aid was replaced with a mixture of bentonite and nano-magnesium oxide. Through intercalation, the magnesium oxide particles could be evenly dispersed in the interlayer structure of bentonite, thus enhancing the structural stability of bentonite, reducing the aggregation of nano-magnesium oxide particles, enabling it to better neutralize gastric acid, and the intercalation causing an increase in the interlayer spacing of bentonite, thereby improving its adsorption performance. Therefore, it could not better synergistically play the adsorption role, resulting in a relatively high content of ammonia in the environment.

[0059] In Comparative Example 3, the protein supplement was replaced with a mixture of zeolite and urea. Through adsorption, the surface-treated zeolite enabled urea to be evenly dispersed in its structure, thus slowing down the loss of urea.

[0060] In Comparative Example 4, the composite nutrient slow-release agent was omitted. The protein supplement could undergo an esterification reaction between the hydroxyl groups on its surface and the carboxyl groups of the acrylic acid solution, forming a spatial network structure of starch-grafted modified acrylic acid solution and the protein supplement. The composite amino acid particles were coated in the spatial network structure, reducing the degradation of amino acids in the rumen, promoting the full absorption of amino acids by the small intestine, thereby improving the utilization rate of amino acids and promoting the growth of rumen microorganisms.

[0061] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0062] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a feed additive for improving rumen digestion efficiency of livestock, characterized in that: The steps include: Step 1: Adding an acrylic acid solution with a neutralization degree of 40-50% and deionized water into a reactor and stirring and mixing, adsorbing urea into zeolite powder to prepare a protein supplement, then adding the protein supplement and gelatinized starch solution into the reactor, stirring at 55-60° C. and 400-500 r / min for 1.5-2 hours, adding sodium sulfite and hydroxymethyl acrylamide into the reactor, stirring at 60-75° C. and 400-550 r / min for 2-3 hours, filtering, washing the filter cake with deionized water and anhydrous ethanol for 2-3 times respectively, and vacuum drying to obtain a composite nutrient slow-release agent; Step 2: Nano-magnesium oxide is intercalated into bentonite particles to prepare a digestive aid, and then the digestive aid, compound nutrient sustained-release agent, compound amino acid particles and microbial preparation are added into a blender in a mass ratio of 25:50:15:5 and mixed evenly, and placed in a feed pellet machine for granulation to obtain a feed additive for improving livestock rumen digestion efficiency.

2. The method for preparing a feed additive for improving livestock rumen digestion efficiency according to claim 1, characterized in that: The usage ratio of the acrylic acid solution, deionized water, protein supplement, gelatinized starch solution, sodium sulfite and hydroxymethyl acrylamide is 200-300 mL: 400-500 mL: 15-18 g: 180-200 mL: 0.5-0.7 g: 0.3-0.5 g.

3. The method for preparing a feed additive for improving rumen digestion efficiency of livestock according to claim 1, wherein the gelatinized starch solution in step 1 is prepared by the following steps: Add starch and deionized water into a reactor, perform gelatinization reaction at 80-90°C and 500-600 r / min for 30-40 min under a nitrogen atmosphere, and cool to 55-65°C to obtain gelatinized starch solution; The usage ratio of the starch to deionized water is 20-30 g: 200-300 mL.

4. The method for preparing a feed additive for improving livestock rumen digestion efficiency according to claim 1, characterized in that: The specific preparation steps of the protein supplement described in step 1 are as follows: Zeolite powder with a particle size of 4-5 mm, dimethyl sulfoxide and hexadecyltrimethylammonium bromide are added into a reactor, stirred at 50-60°C and 500-600r / min for 1-2h, urea is dissolved in anhydrous ethanol and added dropwise into the reactor, stirring is continued for 4-5h, aged at 65-70°C for 24-26h, the product is washed by centrifugation with deionized water for 2-3 times, and vacuum dried at 60-80°C for 1-2h to obtain a protein supplement.

5. The method for preparing a feed additive for improving livestock rumen digestion efficiency according to claim 4, characterized in that: The usage ratio of the zeolite powder, dimethyl sulfoxide, hexadecyltrimethylammonium bromide, urea and anhydrous ethanol is 20-30g: 200-300mL: 2-3g: 30-50g: 400-500mL.

6. The method for preparing a feed additive for improving livestock rumen digestion efficiency according to claim 1, characterized in that: The specific preparation steps of the digestive aid described in step 2 are as follows: Bentonite with a particle size of 2-3 μm and anhydrous ethanol are added into a reactor and stirred and mixed, anhydrous acetic acid and a nitric acid solution with a concentration of 0.5-0.6 mol / L are then added, the mixture is stirred and reacted at 20-25° C. and 800-900 r / min for 1-2 hours, a NaOH solution with a concentration of 0.8-0.9 mol / L is added dropwise, the mixture is aged at 65-70° C. for 24-26 hours, nano magnesium oxide with a particle size of 50-60 nm is ultrasonically dispersed with deionized water and added into the reactor, the mixture is continuously stirred for 40-50 minutes, aged at 65-70° C. for 24-26 hours, the product is centrifugally washed with deionized water for 2-3 times, and vacuum dried at 60-80° C. for 1-2 hours to obtain a digestive aid.

7. The method for preparing a feed additive for improving livestock rumen digestion efficiency according to claim 6, characterized in that: The usage ratio of the bentonite, anhydrous ethanol, anhydrous acetic acid, nitric acid solution, NaOH solution, nano magnesium oxide and deionized water is 20-30g: 400-500mL: 8-10mL: 2-3mL: 1-2mL: 40-50g: 500-600mL.

8. The method for preparing a feed additive for improving livestock rumen digestion efficiency according to claim 1, characterized in that: The composite amino acid particles in step 2 are prepared by dry granulation of carboxymethyl cellulose, cysteine ​​and methionine according to a mass ratio of 20-30:4-5:5-6.

9. The method for preparing a feed additive for improving livestock rumen digestion efficiency according to claim 1, characterized in that: The microbial preparation in step 2 is any one or more of Bacillus subtilis, lactic acid bacteria and ruminant yeast in any mass ratio.

10. A feed additive for improving rumen digestion efficiency of livestock, characterized in that: Prepared by the preparation method according to any one of claims 1 to 9.

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