Trace element feed additive and method for its preparation

Abstract

The application discloses a trace element feed additive and a preparation method thereof, and belongs to the technical field of feed additives.The trace element feed additive comprises the following components in parts by weight: 8-12 parts of polyethylene imine 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.The trace element feed additive is prepared, the nutrition conversion effect of the feed is remarkably improved, the growth and development of animals are promoted, and the technical problem of poor development of animals caused by low trace element absorption in the prior art feed is solved.

Description

Technical Field

[0001] This invention relates to the field of feed additive technology, specifically to a trace element feed additive and its preparation method. Background Technology

[0002] Trace elements are an indispensable and important component of animal nutrition. Although added to feed in extremely small amounts, they play a crucial regulatory role in animal growth and development, reproductive performance, immune function, and metabolic processes. Zinc and selenium, as two core trace elements, have unique biological functions in the animal body. Zinc is a cofactor for more than 300 enzyme systems, participating in important biological processes such as protein synthesis, nucleic acid metabolism, cell division, and immune responses. It also plays a key role in maintaining the integrity of skin and mucous membranes, promoting wound healing, and enhancing the antioxidant defense system. Selenium is an essential component of important enzymes such as glutathione peroxidase, selenoproteins, and thyroid hormone deiodinase, and has functions such as scavenging free radicals, protecting cell membrane integrity, regulating thyroid function, and enhancing the body's immunity. Under modern intensive farming conditions, animals face challenges such as environmental stress, fluctuating feed quality, and accelerated growth rates, significantly increasing their demand for trace elements. The natural trace element content in traditional feeds often cannot meet the nutritional needs of high-producing animals. Therefore, the research and application of trace element feed additives has become an important issue in modern animal nutrition.

[0003] Currently, the most widely used trace element feed additives on 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. First, there 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. Second, inorganic trace elements are prone to oxidation, hydrolysis, and other chemical reactions during feed processing, especially during high-temperature processes such as pelleting and extrusion, where their activity is severely lost. At the same time, they can antagonize vitamins and fats in the feed, affecting the overall nutritional value and leading to poor animal growth and development. Summary of the Invention

[0004] This invention discloses a trace element feed additive and its preparation method. The prepared trace element feed additive significantly improves the nutrient absorption rate of feed, promotes animal growth and development, and solves the technical problem of poor animal development caused by low absorption rate of trace elements in feed in the prior art.

[0005] This invention protects a trace element feed additive, comprising the following components in parts by weight: 8-12 parts polyethyleneimine-modified halloysite, 2-4 parts a mixture of trace elements, 1-2 parts chitosan, 0.5-1.2 parts phytic acid, and 0.8-1.5 parts a stabilizer.

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

[0007] Understandably, halloysite possesses a unique tubular structure with a negatively charged outer surface and a positively charged inner surface, providing an ideal carrier for the selective adsorption of trace elements. Through the amination modification of polyethyleneimine, a large number of positively charged groups are introduced onto the surface of halloysite, enabling the carrier to effectively adsorb negatively charged trace element ions (SeO3). 2－ A strong electrostatic attraction was generated, and the long chain structure of polyethyleneimine formed 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, wherein 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 is understood that this 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 crosslinking density of the coating material, and enhances the stability of the overall structure.

[0013] This invention also protects a method for preparing the above-mentioned trace element feed additive, comprising the following steps:

[0014] Step 1: Dissolve zinc sulfate heptahydrate and sodium selenite in deionized water and sonicate at 40 kHz for 10 minutes to obtain a trace element solution.

[0015] Step 2: Add polyethyleneimine-modified halloysite to the trace element solution at a material-to-liquid ratio of 1:15, shake at 45℃ and 120 r / min for 6 hours, filter, collect the precipitate, wash twice with deionized water to obtain the trace element loading.

[0016] Step 3: Disperse 1000 parts of the trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, and then disperse the precipitate in 1000 parts of phytic acid solution. Centrifuge at 3000 r / min for 15-20 minutes, add 12 parts of sodium tripolyphosphate, and react at 25-35℃ for 1 hour. Use a spray dryer with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 3-5 mL / min. Collect the dried product, which is the trace element feed additive.

[0017] Understandably, this application uses chitosan as the first coating material in the preparation of trace element feed additives. The amino groups on chitosan's molecular chain form hydrogen bonds and electrostatic interactions with the surface of the trace element load, constructing the first protective barrier. Phytic acid, as the second coating material, contains six phosphate groups, which can form ionic crosslinks with the amino groups of chitosan. Simultaneously, the polyphosphate groups of phytic acid form chelate complexes with trace element ions, achieving further stabilization of the trace elements. The composite coating layer exhibits differentiated swelling and degradation behaviors under different pH environments. In the acidic gastric juice environment, the amino groups of chitosan are protonated, enhancing the hydrophilicity of the molecular chain, but the presence of the phytic acid layer inhibits excessive swelling, achieving controlled release. In the neutral to weakly alkaline intestinal environment, the phosphate groups of phytic acid are deprotonated, weakening the crosslinking effect with chitosan and promoting the continuous release of trace elements.

[0018] Preferably, in step one, the weight ratio of zinc sulfate heptahydrate, sodium selenite, and deionized water is 220~250:70~80:400~500.

[0019] Preferably, in step three, the chitosan solution is prepared by the following method: dissolving chitosan in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000, and stirring at 60°C for 2 hours to obtain the chitosan solution.

[0020] Preferably, in step three, the phytic acid solution is prepared by the following method: phytic acid is dissolved in deionized water at a material-to-liquid ratio of 8:1000, the pH is adjusted to 6.5 with 0.1 mol / L sodium hydroxide solution, and the solution is stirred at 25~35℃ for 30 minutes to obtain the phytic acid solution.

[0021] The present invention has the following beneficial effects:

[0022] This invention prepares a trace element feed additive by combining polyethyleneimine-modified halloysite with chitosan-phytic acid composite coating, achieving efficient loading and controlled release of trace elements, and significantly improving the bioavailability and stability of the feed additive.

[0023] (1) This application avoids the aggregation and precipitation phenomenon in the traditional inorganic salt form by loading trace elements in a molecularly dispersed state onto the surface of polyethyleneimine modified halloysite carrier. The nano-size effect of the carrier increases the specific surface area, providing more contact area for intestinal absorption.

[0024] (2) This application achieves the controlled release effect of trace elements by synergistically combining the sustained release effect of 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 destruction of gastric acid environment and gradually release trace elements in the weakly alkaline environment of the intestine, giving the product the characteristic of targeted release. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] The halloysite used in this application's embodiments is from Lingshou County Kexin Mineral Products Co., Ltd.; the polyethyleneimine used is from Nanjing Quanlong Biotechnology Co., Ltd., with a molecular weight of 600 Da; and the chitosan used is from Shanxi Borui Biotechnology Co., Ltd., with a degree of deacetylation ≥85%.

[0027] Example 1

[0028] Step 1: Preparation of Polyethyleneimine Modified Halloysite: Halloysite was pulverized to 100 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:22.5. The pH was adjusted to 2.5 with hydrochloric acid, and the mixture was stirred at 210 r / min for 6 h at 85 °C. After centrifugation, the precipitate was obtained and washed 6 times with deionized water to obtain activated halloysite. 1000 parts of activated halloysite were mixed with 110 parts of polyethyleneimine, and 29 parts of N-hydroxysuccinimide and 39 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride were added. The mixture was reacted at 25 °C for 24 h. After the reaction was completed, the mixture was filtered through a 0.22 μm microfiltration membrane to obtain the precipitate. The precipitate was washed 10 times with deionized water and then vacuum dried at 80 °C for 8 h to obtain polyethyleneimine modified halloysite.

[0029] Step 2, Preparation of trace element solution: Dissolve 235 parts zinc sulfate heptahydrate and 75 parts sodium selenite in 450 parts deionized water, and sonicate at 40 kHz for 10 minutes to obtain trace element solution.

[0030] Step 3: Preparation of trace element loading: Polyethyleneimine modified halloysite was added to the trace element solution at a material-to-liquid ratio of 1:15. The mixture was shaken at 45℃ and 120 r / min for 6 hours. After filtration, the precipitate was collected and washed twice with deionized water to obtain the trace element loading.

[0031] Step 4: Preparation of chitosan solution: Dissolve chitosan in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000 and stir at 60℃ for 2 hours to obtain chitosan solution.

[0032] Step 5: Preparation of phytic acid solution: Dissolve phytic acid in deionized water at a material-to-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 phytic acid solution.

[0033] Step 6: Preparation of trace element feed additive: Disperse 1000 parts of trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000 r / min for 17.5 minutes, add 12 parts of sodium tripolyphosphate, react at 30℃ for 1 hour, and then dry the product by spray drying with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 4 mL / min. This product is the trace element feed additive.

[0034] Example 2

[0035] Step 1: Preparation of Polyethyleneimine Modified Halloysite: Halloysite was pulverized to 80 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:20. The pH was adjusted to 2 with hydrochloric acid, and the mixture was stirred at 180 r / min for 5 h at 80 °C. After centrifugation, the precipitate was obtained and washed 5 times with deionized water to obtain activated halloysite. 1000 parts of activated halloysite were mixed with 100 parts of polyethyleneimine, and 28 parts of N-hydroxysuccinimide and 38 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride were added. The mixture was reacted at 20 °C for 20 h. After the reaction was completed, the mixture was filtered through a 0.22 μm microfiltration membrane to obtain the precipitate. The precipitate was washed 8 times with deionized water and then vacuum dried at 80 °C for 6 h to obtain polyethyleneimine modified halloysite.

[0036] Step 2, Preparation of Trace Element Solution: Dissolve 220 parts zinc sulfate heptahydrate and 70 parts sodium selenite in 400 parts deionized water, and sonicate at 40 kHz for 10 minutes to obtain trace element solution.

[0037] Step 3: Preparation of trace element loading: Polyethyleneimine modified halloysite was added to the trace element solution at a material-to-liquid ratio of 1:15. The mixture was shaken at 45℃ and 120 r / min for 6 hours. After filtration, the precipitate was collected and washed twice with deionized water to obtain the trace element loading.

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

[0039] Step 5: Preparation of phytic acid solution: Dissolve phytic acid in deionized water at a material-to-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 phytic acid solution.

[0040] Step Six: Preparation of Trace Element Feed Additive: Disperse 1000 parts of trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, and then disperse the precipitate in 1000 parts of phytic acid solution. Centrifuge at 3000 r / min for 15 minutes, add 12 parts of sodium tripolyphosphate, and react at 25℃ for 1 hour. Use a spray dryer with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 3 mL / min. Collect the dried product, which is the trace element feed additive.

[0041] Example 3

[0042] Step 1: Preparation of Polyethyleneimine Modified Halloysite: Halloysite was pulverized to 120 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:25. The pH was adjusted to 3 with hydrochloric acid, and the mixture was stirred at 240 r / min for 7 h at 90 °C. After centrifugation, the precipitate was obtained and washed 7 times with deionized water to obtain activated halloysite. 1000 parts of activated halloysite were mixed with 120 parts of polyethyleneimine, and 30 parts of N-hydroxysuccinimide and 40 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride were added. The mixture was reacted at 30 °C for 28 h. After the reaction was completed, the mixture was filtered through a 0.22 μm microfiltration membrane to obtain the precipitate. The precipitate was washed 12 times with deionized water and then vacuum dried at 80 °C for 10 h to obtain polyethyleneimine modified halloysite.

[0043] Step 2, Preparation of Trace Element Solution: Dissolve 250 parts zinc sulfate heptahydrate and 80 parts sodium selenite in 500 parts deionized water, and sonicate at 40 kHz for 10 minutes to obtain the trace element solution.

[0044] Step 3: Preparation of trace element loading: Polyethyleneimine modified halloysite was added to the trace element solution at a material-to-liquid ratio of 1:15. The mixture was shaken at 45℃ and 120 r / min for 6 hours. After filtration, the precipitate was collected and washed twice with deionized water to obtain the trace element loading.

[0045] Step 4: Preparation of chitosan solution: Dissolve chitosan in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000 and stir at 60℃ for 2 hours to obtain chitosan solution.

[0046] Step 5: Preparation of phytic acid solution: Dissolve phytic acid in deionized water at a material-to-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 phytic acid solution.

[0047] Step Six: Preparation of Trace Element Feed Additive: Disperse 1000 parts of trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, and then disperse the precipitate in 1000 parts of phytic acid solution. Centrifuge at 3000 r / min for 20 minutes, add 12 parts of sodium tripolyphosphate, and react at 35℃ for 1 hour. Use a spray dryer with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 5 mL / min. Collect the dried product, which is the trace element feed additive.

[0048] Example 4

[0049] Step 1: Preparation of Polyethyleneimine Modified Halloysite: Halloysite was pulverized to 90 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:21. The pH was adjusted to 2.2 with hydrochloric acid, and the mixture was stirred at 200 r / min for 5.5 h at 82 °C. After centrifugation, the precipitate was obtained and washed 5 times with deionized water to obtain activated halloysite. 1000 parts of activated halloysite were mixed with 105 parts of polyethyleneimine, and 28.5 parts of N-hydroxysuccinimide and 38.5 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride were added. The mixture was reacted at 22 °C for 22 h. After the reaction was completed, the mixture was filtered through a 0.22 μm microfiltration membrane to obtain the precipitate. The precipitate was washed 9 times with deionized water and then vacuum dried at 80 °C for 7 h to obtain polyethyleneimine modified halloysite.

[0050] Step 2, Preparation of Trace Element Solution: Dissolve 230 parts zinc sulfate heptahydrate and 72 parts sodium selenite in 420 parts deionized water, and sonicate at 40 kHz for 10 minutes to obtain trace element solution.

[0051] Step 3: Preparation of trace element loading: Polyethyleneimine modified halloysite was added to the trace element solution at a material-to-liquid ratio of 1:15. The mixture was shaken at 45℃ and 120 r / min for 6 hours. After filtration, the precipitate was collected and washed twice with deionized water to obtain the trace element loading.

[0052] Step 4: Preparation of chitosan solution: Dissolve chitosan in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000 and stir at 60℃ for 2 hours to obtain chitosan solution.

[0053] Step 5: Preparation of phytic acid solution: Dissolve phytic acid in deionized water at a material-to-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 28℃ for 30 minutes to obtain phytic acid solution.

[0054] Step Six: Preparation of Trace Element Feed Additive: Disperse 1000 parts of trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, and then disperse the precipitate in 1000 parts of phytic acid solution. Centrifuge at 3000 r / min for 16 minutes, add 12 parts of sodium tripolyphosphate, and react at 28℃ for 1 hour. Use a spray dryer with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 3.5 mL / min. Collect the dried product, which is the trace element feed additive.

[0055] Example 5

[0056] Step 1: Preparation of Polyethyleneimine Modified Halloysite: Halloysite was pulverized to 110 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:24. The pH was adjusted to 2.8 with hydrochloric acid, and the mixture was stirred at 220 r / min for 6.5 h at 88 °C. After centrifugation, the precipitate was obtained and washed 6 times with deionized water to obtain activated halloysite. 1000 parts of activated halloysite were mixed with 115 parts of polyethyleneimine, and 29.5 parts of N-hydroxysuccinimide and 39.5 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride were added. The mixture was reacted at 28 °C for 26 h. After the reaction was completed, the mixture was filtered through a 0.22 μm microfiltration membrane to obtain the precipitate. The precipitate was washed 11 times with deionized water and then vacuum dried at 80 °C for 9 h to obtain polyethyleneimine modified halloysite.

[0057] Step 2, Preparation of trace element solution: Dissolve 245 parts zinc sulfate heptahydrate and 78 parts sodium selenite in 480 parts deionized water, and sonicate at a frequency of 40 kHz for 10 minutes to obtain trace element solution.

[0058] Step 3: Preparation of trace element loading: Polyethyleneimine modified halloysite was added to the trace element solution at a material-to-liquid ratio of 1:15. The mixture was shaken at 45℃ and 120 r / min for 6 hours. After filtration, the precipitate was collected and washed twice with deionized water to obtain the trace element loading.

[0059] Step 4: Preparation of chitosan solution: Dissolve chitosan in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000 and stir at 60℃ for 2 hours to obtain chitosan solution.

[0060] Step 5: Preparation of phytic acid solution: Dissolve phytic acid in deionized water at a material-to-liquid ratio of 8:1000, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution, and stir at 32℃ for 30 minutes to obtain phytic acid solution.

[0061] Step Six: Preparation of Trace Element Feed Additive: Disperse 1000 parts of trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, and then disperse the precipitate in 1000 parts of phytic acid solution. Centrifuge at 3000 r / min for 18 minutes, add 12 parts of sodium tripolyphosphate, and react at 32℃ for 1 hour. Use a spray dryer with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 4.5 mL / min. Collect the dried product, which is the trace element feed additive.

[0062] Comparative Example 1: Compared with Example 1, step one lacks the polyethyleneimine modification treatment.

[0063] Step 1: Activation of Halloysite: Halloysite was pulverized to 100 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:22.5. The pH was adjusted to 2.5 with hydrochloric acid, and the mixture was stirred at 210 r / min for 6 hours at 85℃. After centrifugation, the precipitate was obtained and washed 6 times with deionized water to obtain activated halloysite. The activated halloysite was then vacuum dried at 80℃ for 8 hours.

[0064] Step 2, Preparation of trace element solution: Dissolve 235 parts zinc sulfate heptahydrate and 75 parts sodium selenite in 450 parts deionized water, and sonicate at 40 kHz for 10 minutes to obtain trace element solution.

[0065] Step 3: Preparation of trace element loading: Add activated halloysite to the trace element solution at a material-to-liquid ratio of 1:15, shake at 45℃ and 120 r / min for 6 hours, filter, collect the precipitate, wash twice with deionized water to obtain the trace element loading.

[0066] Step 4: Preparation of chitosan solution: Dissolve chitosan in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000 and stir at 60℃ for 2 hours to obtain chitosan solution.

[0067] Step 5: Preparation of phytic acid solution: Dissolve phytic acid in deionized water at a material-to-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 phytic acid solution.

[0068] Step 6: Preparation of trace element feed additive: Disperse 1000 parts of trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000 r / min for 17.5 minutes, add 12 parts of sodium tripolyphosphate, react at 30℃ for 1 hour, and then dry the product by spray drying with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 4 mL / min. This product is the trace element feed additive.

[0069] Comparative Example 2: Compared with Example 1, the amount of zinc sulfate used in step two was too small.

[0070] Step 1: Preparation of Polyethyleneimine Modified Halloysite: Halloysite was pulverized to 100 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:22.5. The pH was adjusted to 2.5 with hydrochloric acid, and the mixture was stirred at 210 r / min for 6 h at 85 °C. After centrifugation, the precipitate was obtained and washed 6 times with deionized water to obtain activated halloysite. 1000 parts of activated halloysite were mixed with 110 parts of polyethyleneimine, and 29 parts of N-hydroxysuccinimide and 39 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride were added. The mixture was reacted at 25 °C for 24 h. After the reaction was completed, the mixture was filtered through a 0.22 μm microfiltration membrane to obtain the precipitate. The precipitate was washed 10 times with deionized water and then vacuum dried at 80 °C for 8 h to obtain polyethyleneimine modified halloysite.

[0071] Step 2, Preparation of Trace Element Solution: Dissolve 200 parts zinc sulfate heptahydrate and 100 parts sodium selenite in 450 parts deionized water, and sonicate at 40 kHz for 10 minutes to obtain the trace element solution.

[0072] Step 3: Preparation of trace element loading: Polyethyleneimine modified halloysite was added to the trace element solution at a material-to-liquid ratio of 1:15. The mixture was shaken at 45℃ and 120 r / min for 6 hours. After filtration, the precipitate was collected and washed twice with deionized water to obtain the trace element loading.

[0073] Step 4: Preparation of chitosan solution: Dissolve chitosan in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000 and stir at 60℃ for 2 hours to obtain chitosan solution.

[0074] Step 5: Preparation of phytic acid solution: Dissolve phytic acid in deionized water at a material-to-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 phytic acid solution.

[0075] Step 6: Preparation of trace element feed additive: Disperse 1000 parts of trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, take the precipitate and disperse it in 1000 parts of phytic acid solution, centrifuge at 3000 r / min for 17.5 minutes, add 12 parts of sodium tripolyphosphate, react at 30℃ for 1 hour, and then dry the product by spray drying with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 4 mL / min. This product is the trace element feed additive.

[0076] Comparative Example 3: Compared with Example 1, step five lacks the chitosan coating treatment.

[0077] Step 1: Preparation of Polyethyleneimine Modified Halloysite: Halloysite was pulverized to 100 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:22.5. The pH was adjusted to 2.5 with hydrochloric acid, and the mixture was stirred at 210 r / min for 6 h at 85 °C. After centrifugation, the precipitate was obtained and washed 6 times with deionized water to obtain activated halloysite. 1000 parts of activated halloysite were mixed with 110 parts of polyethyleneimine, and 29 parts of N-hydroxysuccinimide and 39 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride were added. The mixture was reacted at 25 °C for 24 h. After the reaction was completed, the mixture was filtered through a 0.22 μm microfiltration membrane to obtain the precipitate. The precipitate was washed 10 times with deionized water and then vacuum dried at 80 °C for 8 h to obtain polyethyleneimine modified halloysite.

[0078] Step 2, Preparation of trace element solution: Dissolve 235 parts zinc sulfate heptahydrate and 75 parts sodium selenite in 450 parts deionized water, and sonicate at 40 kHz for 10 minutes to obtain trace element solution.

[0079] Step 3: Preparation of trace element loading: Polyethyleneimine modified halloysite was added to the trace element solution at a material-to-liquid ratio of 1:15. The mixture was shaken at 45℃ and 120 r / min for 6 hours. After filtration, the precipitate was collected and washed twice with deionized water to obtain the trace element loading.

[0080] Step 4: Preparation of phytic acid solution: Dissolve phytic acid in deionized water at a material-to-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 phytic acid solution.

[0081] Step 5: Preparation of trace element feed additive: 1000 parts of trace element loading are directly dispersed in 1000 parts of phytic acid solution, centrifuged at 3000 r / min for 17.5 minutes, 12 parts of sodium tripolyphosphate are added, and the mixture is reacted at 30℃ for 1 hour. The product is then dried using a spray dryer with an inlet air temperature of 160℃, an outlet air temperature of 80℃, an atomization pressure of 0.15 MPa, and a feed rate of 4 mL / min. The dried product is the trace element feed additive.

[0082] Comparative Example 4: Compared with Example 1, step five lacks the phytic acid crosslinking treatment.

[0083] Step 1: Preparation of Polyethyleneimine Modified Halloysite: Halloysite was pulverized to 100 mesh and dispersed in deionized water at a material-to-liquid ratio of 1:22.5. The pH was adjusted to 2.5 with hydrochloric acid, and the mixture was stirred at 210 r / min for 6 h at 85 °C. After centrifugation, the precipitate was obtained and washed 6 times with deionized water to obtain activated halloysite. 1000 parts of activated halloysite were mixed with 110 parts of polyethyleneimine, and 29 parts of N-hydroxysuccinimide and 39 parts of 1-ethyl-3-3-dimethylaminopropylcarbodiimide hydrochloride were added. The mixture was reacted at 25 °C for 24 h. After the reaction was completed, the mixture was filtered through a 0.22 μm microfiltration membrane to obtain the precipitate. The precipitate was washed 10 times with deionized water and then vacuum dried at 80 °C for 8 h to obtain polyethyleneimine modified halloysite.

[0084] Step 2, Preparation of trace element solution: Dissolve 235 parts zinc sulfate heptahydrate and 75 parts sodium selenite in 450 parts deionized water, and sonicate at 40 kHz for 10 minutes to obtain trace element solution.

[0085] Step 3: Preparation of trace element loading: Polyethyleneimine modified halloysite was added to the trace element solution at a material-to-liquid ratio of 1:15. The mixture was shaken at 45℃ and 120 r / min for 6 hours. After filtration, the precipitate was collected and washed twice with deionized water to obtain the trace element loading.

[0086] Step 4: Preparation of chitosan solution: Dissolve chitosan in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000 and stir at 60℃ for 2 hours to obtain chitosan solution.

[0087] Step 5: Preparation of trace element feed additive: Disperse 1000 parts of trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, take the precipitate and wash it twice with deionized water, add 12 parts of sodium tripolyphosphate, react at 30℃ for 1 h, and then dry the product by spray drying with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 4 mL / min. The dried product is the trace element feed additive.

[0088] Performance testing

[0089] 1. Selection and grouping of experimental animals

[0090] Step 1: Selection of experimental animals: 200 healthy weaned male SD rats weighing 25±2g were selected and randomly divided into 10 groups of 20 rats each, namely, Example 1-5, Comparative Example 1-4 and Control Group. They were housed in a standard animal room at a temperature of 22℃ with a 12h light / dark cycle.

[0091] Step 2, Adaptation period feeding: All experimental animals were first fed a basic diet for 7 days to adapt, with free access to food and water.

[0092] Step 3: Group feeding during the experimental period: Set up groups 1-5: basal feed + corresponding additives (zinc 15mg / kg, selenium 0.3mg / kg); comparative groups 1-4: basal feed + corresponding comparative additives (added at the same trace element content); blank control group: basal feed with the same trace element content. Conduct the experiment for 28 days.

[0093] 2. Growth performance determination

[0094] Step 1: Weight measurement: Weigh animals on an empty stomach at a fixed time each week (9:00 AM), record the weight changes of each group of animals, and calculate the average daily weight gain (ADG).

[0095] Step 2: Feed intake statistics: Record the amount of feed given and the amount of feed remaining for each group every day, and calculate the average daily feed intake (ADFI).

[0096] Step 3: Calculate feed conversion ratio: Based on body weight gain and feed intake data, calculate feed conversion ratio (FCR) = ADFI / ADG.

[0097] Test Result Data Table

[0098] Table 1. Results of Growth Performance Indicators Tests

[0099]

[0100] Data Analysis

[0101] As can be seen from Table 1, the growth performance and feed conversion effect of Examples 1-5 are significantly better than those of Comparative Examples 1-8, indicating that the trace element feed additive of the present invention significantly improves the nutritional conversion effect of feed and significantly promotes the growth and development of mice.

[0102] Although 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 can 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 patent coverage of the present invention.

Claims

1. A trace element feed additive, characterized in that, The product comprises the following components in parts by weight: 8-12 parts polyethyleneimine-modified halloysite, 2-4 parts trace element mixture, 1-2 parts chitosan, 0.5-1.2 parts phytic acid, and 0.8-1.5 parts stabilizer. The polyethyleneimine-modified halloysite is prepared by the following method: halloysite is pulverized to 80-120 mesh, dispersed in deionized water at a material-to-liquid ratio of 1:20-25, the pH is adjusted to 2-3 with hydrochloric acid, and the mixture is subjected to a rotation speed of 180-240 r / min at 80-90℃. Stir for 5–7 h, centrifuge to obtain a precipitate, wash with deionized water 5–7 times to obtain activated halloysite, mix activated halloysite and polyethyleneimine, add N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, react at 20–30 °C for 20–28 h, filter with a 0.22 μm microfiltration membrane to obtain a precipitate, wash with deionized water 8–12 times, and then vacuum dry at 80 °C for 6–10 h to obtain polyethyleneimine modified halloysite.

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

3. The trace element feed additive according to claim 1, characterized in that, The molecular weight of the polyethyleneimine is 400~800 Da.

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

1.

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

6. A method for preparing the trace element feed additive according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Dissolve zinc sulfate heptahydrate and sodium selenite in deionized water and sonicate at 40 kHz for 10 minutes to obtain a trace element solution. Step 2: Add polyethyleneimine-modified halloysite to the trace element solution at a material-to-liquid ratio of 1:15, shake at 45℃ and 120 r / min for 6 hours, filter, collect the precipitate, wash twice with deionized water to obtain the trace element loading. Step 3: Disperse 1000 parts of the trace element loading in 1000 parts of chitosan solution, centrifuge at 3000 r / min for 5 minutes, filter, and then disperse the precipitate in 1000 parts of phytic acid solution. Centrifuge at 3000 r / min for 15-20 minutes, add 12 parts of sodium tripolyphosphate, and react at 25-35℃ for 1 hour. Use a spray dryer with the inlet air temperature set at 160℃, the outlet air temperature at 80℃, the atomization pressure at 0.15 MPa, and the feed rate at 3-5 mL / min. Collect the dried product, which is the trace element feed additive.

7. The preparation method according to claim 6, characterized in that, In step one, the weight ratio of zinc sulfate heptahydrate, sodium selenite, and deionized water is 220~250:70~80:400~500.

8. The preparation method according to claim 6, characterized in that, In step three, the chitosan solution is prepared by the following method: chitosan is dissolved in a 1% acetic acid solution at a material-to-liquid ratio of 15:1000, and stirred at 60°C for 2 hours to obtain the chitosan solution.

9. The preparation method according to claim 6, characterized in that, In step three, the phytic acid solution is prepared by the following method: phytic acid is dissolved in deionized water at a material-to-liquid ratio of 8:1000, the pH is adjusted to 6.5 with 0.1 mol / L sodium hydroxide solution, and the solution is stirred at 25~35℃ for 30 minutes to obtain the phytic acid solution.

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