Trace element feed additive and preparation method thereof

Abstract

The invention discloses a trace element feed additive and a preparation method thereof, and belongs to the technical field of feed additives, and the trace element feed additive comprises the following components in parts by weight: 8-12 parts of polyethyleneimine modified halloysite, 2-4 parts of a trace element mixture, 1-2 parts of chitosan, 0.5-1.2 parts of phytic acid and 0.8-1.5 parts of a stabilizer. According to the microelement feed additive prepared by the invention, the nutrition conversion effect of the feed is remarkably improved, the growth and development of animals are promoted, and the technical problem of animal dysplasia caused by low absorption rate of microelements in the feed in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of feed additives, and in particular to a trace element feed additive and a preparation method thereof. Background Art

[0002] Trace elements are essential components of animal nutrition. Despite being added in minimal amounts to feed, they play a crucial role in regulating animal growth and development, reproductive performance, immune function, and metabolic processes. Zinc and selenium, two core trace elements, possess unique biological functions within the animal body. Zinc is a cofactor in over 300 enzyme systems, participating in vital biological processes such as protein synthesis, nucleic acid metabolism, cell division, and immune response. It also plays a key role in maintaining the integrity of skin and mucous membranes, promoting wound healing, and enhancing antioxidant defenses. Selenium is an essential component of key enzymes such as glutathione peroxidase, selenoproteins, and thyroid hormone deiodinase. It scavenges free radicals, protects cell membrane integrity, regulates thyroid function, and enhances immunity. Under modern intensive farming conditions, animals face challenges such as environmental stress, fluctuating feed quality, and accelerated growth rates, resulting in a significantly increased demand for trace elements. The natural trace element content in traditional feeds often fails to meet the nutritional needs of high-yielding animals. Therefore, the research and application of trace element feed additives has become a key issue in modern animal nutrition.

[0003] The trace element feed additives currently widely used in the market are mainly in the form of inorganic salts such as zinc sulfate, zinc chloride, sodium selenite, and sodium selenate. These traditional additives have many technical bottlenecks and application limitations. The first is the problem of low bioavailability. Inorganic trace elements easily combine with anti-nutritional factors such as cellulose, phytic acid, and oxalic acid in the animal digestive tract to form insoluble complexes, resulting in reduced absorption rate. Secondly, inorganic trace elements are prone to chemical reactions such as oxidation and hydrolysis during feed processing. In particular, the activity is severely lost during high-temperature processes such as granulation and puffing. At the same time, they react antagonistically with vitamins, fats and other components in the feed, affecting the overall nutritional value and leading to poor growth and development of animals. Summary of the Invention

[0004] The invention discloses a trace element feed additive and a preparation method thereof. The invention prepares a trace element feed additive, which significantly improves the nutrient absorption rate of feed, promotes the growth and development of animals, and solves the technical problem of low trace element absorption rate in feed in the prior art leading to poor development of animals.

[0005] The invention provides a trace element feed additive, which comprises the following components in parts by weight: 8 to 12 parts of polyethyleneimine modified halloysite, 2 to 4 parts of a trace element mixture, 1 to 2 parts of chitosan, 0.5 to 1.2 parts of phytic acid and 0.8 to 1.5 parts of a stabilizer.

[0006] Preferably, the polyethyleneimine-modified halloysite is prepared by the following method: the halloysite is crushed to 80-120 mesh, dispersed in deionized water at a material-liquid ratio of 1:20-25, the pH is adjusted to 2-3 with hydrochloric acid, stirred at 180-240 r / min at 80-90° C. for 5-7 hours, centrifuged to obtain a precipitate, washed with deionized water 5-7 times to obtain activated halloysite, the activated halloysite and polyethyleneimine are mixed, N-hydroxysuccinimide and 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride are added, reacted at 20-30° C. for 20-28 hours, filtered with a 0.22 μm microfiltration membrane after the reaction is completed, the precipitate is washed with deionized water 8-12 times, and then vacuum dried at 80° C. for 6-10 hours to obtain polyethyleneimine-modified halloysite.

[0007] It is understandable that halloysite has a unique tubular structure with a negatively charged outer surface and a positively charged inner cavity, which provides an ideal carrier for the selective adsorption of trace elements. By modifying the halloysite surface with polyethyleneimine, a large number of positively charged groups are introduced to make the carrier selectively adsorb the negatively charged trace element ions SeO3. 2－ A strong electrostatic attraction is generated, and at the same time, the long chain structure of polyethyleneimine forms a three-dimensional network structure on the halloysite surface, providing a large number of binding sites for trace elements.

[0008] Preferably, the mass ratio of the activated halloysite, polyethyleneimine, N-hydroxysuccinimide and 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride is 1000:100~120:28~30:38~40.

[0009] Preferably, the molecular weight of the polyethyleneimine is 400-800 Da.

[0010] Preferably, the trace element mixture comprises zinc sulfate heptahydrate and sodium selenite, and the mass ratio of zinc sulfate heptahydrate to sodium selenite is 2.5-3.5:1.

[0011] Preferably, the stabilizer is sodium tripolyphosphate.

[0012] It can be understood that the present application uses sodium tripolyphosphate as a stabilizer, whose molecular structure contains multiple phosphate groups, which can form stable chelates with trace element ions to prevent oxidation and hydrolysis of trace elements during storage and transportation; at the same time, the addition of sodium tripolyphosphate adjusts the ionic strength of the system, optimizes the cross-linking density of the coating material, and enhances the stability of the overall structure.

[0013] The present invention also provides a method for preparing the above-mentioned trace element feed additive, comprising the following steps: Step one, dissolve zinc sulfate heptahydrate and sodium selenite in deionized water, ultrasonic at a frequency of 40 kHz for 10 minutes to obtain trace element solution; Step two, add polyethyleneimine modified halloysite to the trace element solution according to the solid-liquid ratio of 1:15, oscillate at a frequency of 120 r / min for 6 hours at 45℃, filter, wash the precipitate with deionized water for 2 times to obtain trace element support; Step three, disperse 1000 parts of trace element support in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, take the precipitate after filtration and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000 r / min for 15-20 minutes, add 12 parts of sodium tripolyphosphate, react at 25-35℃ for 1h, collect the dry product through a spray dryer, set the inlet air temperature at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feeding speed at 3-5 mL / min, which is the trace element feed additive.

[0014] It can be understood that, in the preparation of the trace element feed additive, chitosan is used as the first layer of coating material, the amino groups on the molecular chain of which form hydrogen bonds and electrostatic interactions with the surface of the trace element support, thereby constructing the first protective barrier; phytic acid is used as the second layer of coating material, the molecule of which contains 6 phosphate groups and can form ionic crosslinking with the amino groups of chitosan, and the polyphosphate groups of phytic acid can form chelate complexes with trace element ions, thereby achieving the further stabilization of trace elements. The composite coating layer exhibits differential swelling and degradation behavior in different pH environments. In the acidic gastric juice environment, the amino groups of chitosan are protonated, which enhances the hydrophilicity of the molecular chain, but the presence of the phytic acid layer inhibits excessive swelling, thereby achieving controlled release. In the neutral to weakly alkaline intestinal environment, the phosphate groups of phytic acid are deprotonated, which weakens the crosslinking effect with chitosan and promotes the sustained release of trace elements.

[0015] Preferably, in step one, the weight ratio of zinc sulfate heptahydrate, sodium selenite and deionized water is 220-250:70-80:400-500.

[0016] Preferably, in step three, the chitosan solution is prepared by the following method: dissolve chitosan in 1% acetic acid solution according to the solid-liquid ratio of 15:1000, stir at 60℃ for 2h to obtain the chitosan solution.

[0017] Preferably, in step three, the phytic acid solution is prepared by the following method: dissolve phytic acid in deionized water according to the solid-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, stir at 25-35℃ for 30 minutes to obtain the phytic acid solution.

[0018] The present invention has the following beneficial effects: The present invention prepares a trace element feed additive by combining polyethyleneimine-modified halloysite with chitosan-phytic acid composite coating, thereby achieving efficient loading and controlled release of trace elements and significantly improving the bioavailability and stability of the feed additive.

[0019] (1) This application avoids the aggregation and precipitation phenomena in the traditional inorganic salt form by loading trace elements in a molecularly dispersed state on the surface of the polyethyleneimine modified halloysite carrier. The nano-size effect of the carrier increases the specific surface area, providing more contact area for intestinal absorption.

[0020] (2) This application achieves the controlled release effect of trace elements by synergizing the sustained-release effect of the halloysite carrier, the biocompatibility of chitosan, the chelating stability of phytic acid, and the dispersion stability of sodium tripolyphosphate. At the same time, this multi-layer coating structure can effectively resist the damage of the gastric acid environment and gradually release trace elements in the weak alkaline environment of the intestine, giving the product the characteristics of targeted release. DETAILED DESCRIPTION

[0021] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] The halloysite used in the examples of this application is sourced from Lingshou County Kexin Mineral Products Co., Ltd.; the polyethyleneimine used is sourced from Nanjing Quanlong Biotechnology Co., Ltd., with a molecular weight of 600 Da; and the chitosan used is sourced from Shanxi Borui Biotechnology Co., Ltd., with a deacetylation degree ≥85%.

[0023] Example 1 Step 1, preparation of polyethyleneimine-modified halloysite: crush the halloysite to 100 mesh, disperse it in deionized water at a material-liquid ratio of 1:22.5, adjust the pH to 2.5 with hydrochloric acid, stir at 210r / min at 85°C for 6h, centrifuge to obtain a precipitate, and wash it 6 times with deionized water to obtain activated halloysite. Take 1000 parts of activated halloysite and mix it with 110 parts of polyethyleneimine, add 29 parts of N-hydroxysuccinimide and 39 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, react at 25°C for 24h, filter it with a 0.22μm microfiltration membrane after the reaction is completed, wash the precipitate with deionized water 10 times, and then vacuum dry it at 80°C for 8h to obtain polyethyleneimine-modified halloysite.

[0024] Step 2: Preparation of trace element solution: Dissolve 235 parts of zinc sulfate heptahydrate and 75 parts of sodium selenite in 450 parts of deionized water, and ultrasonicate at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0025] Step 3: Preparation of trace element loading material: Add polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0026] Step 4: Preparation of chitosan solution: Dissolve chitosan in 1% acetic acid solution at a material-liquid ratio of 15:1000, and stir at 60° C. for 2 h to obtain a chitosan solution.

[0027] Step 5, preparation of phytic acid solution: dissolve phytic acid in deionized water at a material-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 30° C. for 30 minutes to obtain a phytic acid solution.

[0028] Step 6. Preparation of trace element feed additive: disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000r / min for 17.5 minutes, add 12 parts of sodium tripolyphosphate, react at 30℃ for 1h, pass through a spray dryer, set the inlet air temperature to 160℃, the outlet air temperature to 80℃, the atomization pressure to 0.15MPa, and the feed rate to 4mL / min, collect the dry product, which is the trace element feed additive.

[0029] Example 2 Step 1, preparation of polyethyleneimine-modified halloysite: crush the halloysite to 80 mesh, disperse it in deionized water at a material-liquid ratio of 1:20, adjust the pH to 2 with hydrochloric acid, stir it at 180r / min at 80°C for 5h, centrifuge to obtain a precipitate, and wash it 5 times with deionized water to obtain activated halloysite. Take 1000 parts of activated halloysite and mix it with 100 parts of polyethyleneimine, add 28 parts of N-hydroxysuccinimide and 38 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, react at 20°C for 20h, filter it with a 0.22μm microfiltration membrane after the reaction is completed, wash the precipitate with deionized water 8 times, and then vacuum dry it at 80°C for 6h to obtain polyethyleneimine-modified halloysite.

[0030] Step 2: Preparation of trace element solution: 220 parts of zinc sulfate heptahydrate and 70 parts of sodium selenite were dissolved in 400 parts of deionized water, and ultrasonicated at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0031] Step 3: Preparation of trace element loading material: Add polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0032] Step 4: Preparation of chitosan solution: Dissolve chitosan in 1% acetic acid solution at a material-liquid ratio of 15:1000, and stir at 60° C. for 2 h to obtain a chitosan solution.

[0033] Step 5, preparation of phytic acid solution: dissolve phytic acid in deionized water at a material-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 25° C. for 30 minutes to obtain a phytic acid solution.

[0034] Step 6. Preparation of trace element feed additive: disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000r / min for 15 minutes, add 12 parts of sodium tripolyphosphate, react at 25℃ for 1h, pass through a spray dryer, set the inlet air temperature to 160℃, the outlet air temperature to 80℃, the atomization pressure to 0.15MPa, and the feed rate to 3mL / min, collect the dry product, which is the trace element feed additive.

[0035] Example 3 Step 1, preparation of polyethyleneimine-modified halloysite: crush the halloysite to 120 mesh, disperse it in deionized water at a material-liquid ratio of 1:25, adjust the pH to 3 with hydrochloric acid, stir it at 240r / min at 90°C for 7h, centrifuge to obtain a precipitate, and wash it 7 times with deionized water to obtain activated halloysite. Take 1000 parts of activated halloysite and mix it with 120 parts of polyethyleneimine, add 30 parts of N-hydroxysuccinimide and 40 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, react at 30°C for 28h, filter it with a 0.22μm microfiltration membrane after the reaction is completed, wash the precipitate with deionized water 12 times, and then vacuum dry it at 80°C for 10h to obtain polyethyleneimine-modified halloysite.

[0036] Step 2: Preparation of trace element solution: Dissolve 250 parts of zinc sulfate heptahydrate and 80 parts of sodium selenite in 500 parts of deionized water, and ultrasonicate at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0037] Step 3: Preparation of trace element loading material: Add polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0038] Step 4: Preparation of chitosan solution: Dissolve chitosan in 1% acetic acid solution at a material-liquid ratio of 15:1000, and stir at 60° C. for 2 h to obtain a chitosan solution.

[0039] Step 5, preparation of phytic acid solution: dissolve phytic acid in deionized water at a material-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 35° C. for 30 minutes to obtain a phytic acid solution.

[0040] Step 6. Preparation of trace element feed additive: disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000r / min for 20 minutes, add 12 parts of sodium tripolyphosphate, react at 35℃ for 1h, pass through a spray dryer, set the inlet air temperature to 160℃, the outlet air temperature to 80℃, the atomization pressure to 0.15MPa, and the feed rate to 5mL / min, collect the dry product, which is the trace element feed additive.

[0041] Example 4 Step 1, preparation of polyethyleneimine-modified halloysite: crush the halloysite to 90 mesh, disperse it in deionized water at a material-liquid ratio of 1:21, adjust the pH to 2.2 with hydrochloric acid, stir at 200r / min at 82°C for 5.5h, centrifuge to obtain a precipitate, and wash it 5 times with deionized water to obtain activated halloysite. Take 1000 parts of activated halloysite and mix it with 105 parts of polyethyleneimine, add 28.5 parts of N-hydroxysuccinimide and 38.5 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, react at 22°C for 22h, filter it with a 0.22μm microfiltration membrane after the reaction is completed, wash the precipitate with deionized water 9 times, and then vacuum dry it at 80°C for 7h to obtain polyethyleneimine-modified halloysite.

[0042] Step 2: Preparation of trace element solution: 230 parts of zinc sulfate heptahydrate and 72 parts of sodium selenite were dissolved in 420 parts of deionized water, and ultrasonicated at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0043] Step 3: Preparation of trace element loading material: Add polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0044] Step 4: Preparation of chitosan solution: Dissolve chitosan in 1% acetic acid solution at a material-liquid ratio of 15:1000, and stir at 60° C. for 2 h to obtain a chitosan solution.

[0045] Step 5, preparation of phytic acid solution: dissolve phytic acid in deionized water at a material-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 28° C. for 30 minutes to obtain a phytic acid solution.

[0046] Step 6. Preparation of trace element feed additive: disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000r / min for 16 minutes, add 12 parts of sodium tripolyphosphate, react at 28°C for 1h, pass through a spray dryer, set the inlet air temperature to 160°C, the outlet air temperature to 80°C, the atomization pressure to 0.15MPa, and the feed rate to 3.5mL / min, collect the dry product, which is the trace element feed additive.

[0047] Example 5 Step 1, preparation of polyethyleneimine-modified halloysite: crush the halloysite to 110 mesh, disperse it in deionized water at a material-liquid ratio of 1:24, adjust the pH to 2.8 with hydrochloric acid, stir it at 220r / min at 88°C for 6.5h, centrifuge to obtain a precipitate, and wash it 6 times with deionized water to obtain activated halloysite. Take 1000 parts of activated halloysite and mix it with 115 parts of polyethyleneimine, add 29.5 parts of N-hydroxysuccinimide and 39.5 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, react at 28°C for 26h, filter it with a 0.22μm microfiltration membrane after the reaction is completed, wash the precipitate with deionized water 11 times, and then vacuum dry it at 80°C for 9h to obtain polyethyleneimine-modified halloysite.

[0048] Step 2: Preparation of trace element solution: Dissolve 245 parts of zinc sulfate heptahydrate and 78 parts of sodium selenite in 480 parts of deionized water, and ultrasonicate at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0049] Step 3: Preparation of trace element loading material: Add polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0050] Step 4: Preparation of chitosan solution: Dissolve chitosan in 1% acetic acid solution at a material-liquid ratio of 15:1000, and stir at 60° C. for 2 h to obtain a chitosan solution.

[0051] Step 5, preparation of phytic acid solution: dissolve phytic acid in deionized water at a material-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 32° C. for 30 minutes to obtain a phytic acid solution.

[0052] Step 6. Preparation of trace element feed additive: disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000r / min for 18 minutes, add 12 parts of sodium tripolyphosphate, react at 32°C for 1h, pass through a spray dryer, set the inlet air temperature to 160°C, the outlet air temperature to 80°C, the atomization pressure to 0.15MPa, and the feed rate to 4.5mL / min, collect the dry product, which is the trace element feed additive.

[0053] Comparative Example 1: Compared with Example 1, the polyethyleneimine modification treatment is missing in step 1.

[0054] Step 1: Activation of Halloysite: Halloysite was crushed to 100 mesh and dispersed in deionized water at a solid-liquid ratio of 1:22.5. The pH was adjusted to 2.5 with hydrochloric acid. The mixture was stirred at 210 rpm at 85°C for 6 hours. The precipitate was centrifuged to obtain activated halloysite. The precipitate was washed six times with deionized water. The activated halloysite was then dried under vacuum at 80°C for 8 hours.

[0055] Step 2: Preparation of trace element solution: Dissolve 235 parts of zinc sulfate heptahydrate and 75 parts of sodium selenite in 450 parts of deionized water, and ultrasonicate at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0056] Step 3: Preparation of trace element loading material: Add activated halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0057] Step 4: Preparation of chitosan solution: Dissolve chitosan in 1% acetic acid solution at a material-liquid ratio of 15:1000, and stir at 60° C. for 2 h to obtain a chitosan solution.

[0058] Step 5, preparation of phytic acid solution: dissolve phytic acid in deionized water at a material-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 30° C. for 30 minutes to obtain a phytic acid solution.

[0059] Step 6. Preparation of trace element feed additive: disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000r / min for 17.5 minutes, add 12 parts of sodium tripolyphosphate, react at 30℃ for 1h, pass through a spray dryer, set the inlet air temperature to 160℃, the outlet air temperature to 80℃, the atomization pressure to 0.15MPa, and the feed rate to 4mL / min, collect the dry product, which is the trace element feed additive.

[0060] Comparative Example 2: Compared with Example 1, the amount of zinc sulfate used in step 2 is too small.

[0061] Step 1, preparation of polyethyleneimine-modified halloysite: crush the halloysite to 100 mesh, disperse it in deionized water at a material-liquid ratio of 1:22.5, adjust the pH to 2.5 with hydrochloric acid, stir at 210r / min at 85°C for 6h, centrifuge to obtain a precipitate, and wash it 6 times with deionized water to obtain activated halloysite. Take 1000 parts of activated halloysite and mix it with 110 parts of polyethyleneimine, add 29 parts of N-hydroxysuccinimide and 39 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, react at 25°C for 24h, filter it with a 0.22μm microfiltration membrane after the reaction is completed, wash the precipitate with deionized water 10 times, and then vacuum dry it at 80°C for 8h to obtain polyethyleneimine-modified halloysite.

[0062] Step 2: Preparation of trace element solution: Dissolve 200 parts of zinc sulfate heptahydrate and 100 parts of sodium selenite in 450 parts of deionized water, and ultrasonicate at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0063] Step 3: Preparation of trace element loading material: Add polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0064] Step 4: Preparation of chitosan solution: Dissolve chitosan in 1% acetic acid solution at a material-liquid ratio of 15:1000, and stir at 60° C. for 2 h to obtain a chitosan solution.

[0065] Step 5, preparation of phytic acid solution: dissolve phytic acid in deionized water at a material-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 30° C. for 30 minutes to obtain a phytic acid solution.

[0066] Step 6. Preparation of trace element feed additive: disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000r / min for 17.5 minutes, add 12 parts of sodium tripolyphosphate, react at 30℃ for 1h, pass through a spray dryer, set the inlet air temperature to 160℃, the outlet air temperature to 80℃, the atomization pressure to 0.15MPa, and the feed rate to 4mL / min, collect the dry product, which is the trace element feed additive.

[0067] Comparative Example 3: Compared with Example 1, the chitosan coating treatment is missing in step 5.

[0068] Step 1, preparation of polyethyleneimine-modified halloysite: crush the halloysite to 100 mesh, disperse it in deionized water at a material-liquid ratio of 1:22.5, adjust the pH to 2.5 with hydrochloric acid, stir at 210r / min at 85°C for 6h, centrifuge to obtain a precipitate, and wash it 6 times with deionized water to obtain activated halloysite. Take 1000 parts of activated halloysite and mix it with 110 parts of polyethyleneimine, add 29 parts of N-hydroxysuccinimide and 39 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, react at 25°C for 24h, filter it with a 0.22μm microfiltration membrane after the reaction is completed, wash the precipitate with deionized water 10 times, and then vacuum dry it at 80°C for 8h to obtain polyethyleneimine-modified halloysite.

[0069] Step 2: Preparation of trace element solution: Dissolve 235 parts of zinc sulfate heptahydrate and 75 parts of sodium selenite in 450 parts of deionized water, and ultrasonicate at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0070] Step 3: Preparation of trace element loading material: Add polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0071] Step 4, preparation of phytic acid solution: dissolve phytic acid in deionized water at a material-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 30° C. for 30 minutes to obtain a phytic acid solution.

[0072] Step 5. Preparation of trace element feed additive: 1000 parts of trace element load are directly dispersed in 1000 parts of phytic acid solution, centrifuged at 3000r / min for 17.5 minutes, 12 parts of sodium tripolyphosphate are added, and the mixture is reacted at 30°C for 1 hour. The mixture is passed through a spray dryer with the inlet air temperature set at 160°C, the outlet air temperature set at 80°C, the atomization pressure set at 0.15MPa, and the feed rate set at 4mL / min. The dry product is collected to obtain the trace element feed additive.

[0073] Comparative Example 4: Compared with Example 1, the phytic acid cross-linking treatment is missing in step 5.

[0074] Step 1, preparation of polyethyleneimine-modified halloysite: crush the halloysite to 100 mesh, disperse it in deionized water at a material-liquid ratio of 1:22.5, adjust the pH to 2.5 with hydrochloric acid, stir at 210r / min at 85°C for 6h, centrifuge to obtain a precipitate, and wash it 6 times with deionized water to obtain activated halloysite. Take 1000 parts of activated halloysite and mix it with 110 parts of polyethyleneimine, add 29 parts of N-hydroxysuccinimide and 39 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, react at 25°C for 24h, filter it with a 0.22μm microfiltration membrane after the reaction is completed, wash the precipitate with deionized water 10 times, and then vacuum dry it at 80°C for 8h to obtain polyethyleneimine-modified halloysite.

[0075] Step 2: Preparation of trace element solution: Dissolve 235 parts of zinc sulfate heptahydrate and 75 parts of sodium selenite in 450 parts of deionized water, and ultrasonicate at a frequency of 40 kHz for 10 minutes to obtain a trace element solution.

[0076] Step 3: Preparation of trace element loading material: Add polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shake at 45°C and a frequency of 120 r / min for 6 hours, filter, collect the precipitate, and wash twice with deionized water to obtain the trace element loading material.

[0077] Step 4: Preparation of chitosan solution: Dissolve chitosan in 1% acetic acid solution at a material-liquid ratio of 15:1000, and stir at 60° C. for 2 h to obtain a chitosan solution.

[0078] Step 5. Preparation of trace element feed additive: Disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and wash the precipitate twice with deionized water, add 12 parts of sodium tripolyphosphate, react at 30℃ for 1h, pass through a spray dryer, set the inlet air temperature to 160℃, the outlet air temperature to 80℃, the atomization pressure to 0.15MPa, and the feed rate to 4mL / min, collect the dry product, which is the trace element feed additive.

[0079] Performance testing 1. Selection and grouping of experimental animals Step 1. Selection of experimental animals: 200 healthy weaned male SD rats weighing 25±2 g were selected and randomly divided into 10 groups, 20 rats in each group, namely Example 1-5 groups, Comparative Example 1-4 groups and a control group. They were raised in a standard animal room at a temperature of 22°C and a 12-h light / dark cycle.

[0080] Step 2: Adaptation period feeding: All experimental animals were first fed with basic feed for 7 days for adaptation, with free access to food and water.

[0081] Step 3: Experimental period: Group feeding: Example 1-5 groups: basal feed + corresponding example additives (15 mg / kg zinc, 0.3 mg / kg selenium); Comparative Example 1-4 groups: basal feed + corresponding comparative example additives (supplemented with the same trace element content); blank control group: basal feed supplemented with the same trace element content. The experimental period was 28 days.

[0082] 2. Growth Performance Determination Step 1. Body weight measurement: Weigh the animals on an empty stomach at a fixed time every week (9:00 am), record the weight changes of each group of animals, and calculate the average daily gain (ADG).

[0083] Step 2: Feed intake statistics: Record the amount of feed fed and the remaining amount for each group every day and calculate the average daily feed intake (ADFI).

[0084] Step 3. Calculate feed conversion ratio: Based on weight gain and feed intake data, calculate feed conversion efficiency (FCR) = ADFI / ADG.

[0085] Test result data table Table 1. Growth performance index test results

[0086] Data Analysis As can be seen from Table 1, the growth performance and feed conversion effect of Examples 1 to 5 are significantly better than those of Comparative Examples 1 to 8, indicating that the trace element feed additive of the technical solution of the present invention significantly improves the nutrient conversion effect of feed and significantly promotes the growth and development of mice.

[0087] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A trace element feed additive, characterized in that: The invention comprises the following components in parts by weight: 8 to 12 parts of polyethyleneimine modified halloysite, 2 to 4 parts of trace element mixture, 1 to 2 parts of chitosan, 0.5 to 1.2 parts of phytic acid and 0.8 to 1.5 parts of stabilizer.

2. The trace element feed additive according to claim 1, characterized in that The polyethyleneimine-modified halloysite is prepared by the following method: crushing the halloysite into 80-120 meshes, dispersing it in deionized water at a material-liquid ratio of 1:20-25, adjusting the pH to 2-3 with hydrochloric acid, stirring at a speed of 180-240 r / min at 80-90° C. for 5-7 hours, centrifuging to obtain a precipitate, washing it with deionized water for 5-7 times to obtain activated halloysite, mixing the activated halloysite with polyethyleneimine, adding N-hydroxysuccinimide and 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride, reacting at 20-30° C. for 20-28 hours, filtering with a 0.22 μm microfiltration membrane after the reaction is completed, washing the precipitate with deionized water for 8-12 times, and then vacuum drying it at 80° C. for 6-10 hours to obtain the polyethyleneimine-modified halloysite.

3. The trace element feed additive according to claim 2, characterized in that The mass ratio of the activated halloysite, polyethyleneimine, N-hydroxysuccinimide and 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride is 1000:100-120:28-30:38-40.

4. The trace element feed additive according to claim 2, characterized in that The molecular weight of the polyethyleneimine is 400-800 Da.

5. The trace element feed additive according to claim 1, characterized in that The trace element mixture includes zinc sulfate heptahydrate and sodium selenite, and the mass ratio of the zinc sulfate heptahydrate to the sodium selenite is 2.5-3.5:

1.

6. The trace element feed additive according to claim 1, characterized in that The stabilizer is sodium tripolyphosphate.

7. The method for preparing the trace element feed additive according to claims 1 to 9, characterized in that: The following steps are involved: Step 1: Dissolve zinc sulfate heptahydrate and sodium selenite in deionized water, and ultrasonicate at a frequency of 40 kHz for 10 minutes to obtain a trace element solution; Step 2: adding polyethyleneimine-modified halloysite to the trace element solution at a material-liquid ratio of 1:15, shaking at 45° C. and a frequency of 120 r / min for 6 hours, filtering, collecting the precipitate, and washing twice with deionized water to obtain a trace element loading; Step 3: Disperse 1000 parts of trace element load in 1000 parts of chitosan solution, centrifuge at 3000r / min for 5 minutes, filter and take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000r / min for 15-20 minutes, add 12 parts of sodium tripolyphosphate, react at 25-35℃ for 1h, pass through a spray dryer, set the inlet temperature to 160℃, the outlet temperature to 80℃, the atomization pressure to 0.15MPa, and the feed rate to 3-5mL / min, collect the dry product, which is the trace element feed additive.

8. The preparation method according to claim 7, characterized in that In step 1, the weight ratio of the zinc sulfate heptahydrate, sodium selenite and deionized water is 220-250:70-80:400-500.

9. The preparation method according to claim 7, characterized in that In step 3, the chitosan solution is prepared by the following method: dissolving chitosan in a 1% acetic acid solution at a material-liquid ratio of 15:1000, and stirring at 60° C. for 2 h to obtain a chitosan solution.

10. The preparation method according to claim 7, characterized in that In step three, the phytic acid solution is prepared by the following method: dissolving phytic acid in deionized water at a material-liquid ratio of 8:1000, adjusting the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stirring at 25-35° C. for 30 minutes to obtain a phytic acid solution.

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