Slow-release xanthophyll additive, preparation method and application of slow-release xanthophyll additive in feed

Abstract

The preparation method of the slow-release xanthophyll additive comprises the following steps that a calcium chloride solution with the mass concentration of 2%-5% is dropwise added into primary emulsion, the dropwise adding speed is 1-2 mL / min, stirring crosslinking is conducted for 30-60 min, and the adding amount of the calcium chloride solution is 5%-10% of the volume of the primary emulsion; and adding the crosslinked emulsion into nano coating equipment, introducing nitrogen for protection, and carrying out nano deposition coating at 40-50 DEG C for 20-40 minutes. The feed additive is suitable for various animal feeds such as livestock and poultry, aquatic products and the like, and is low in addition amount and controllable in cost; industrial production can be realized by adopting conventional equipment, the production efficiency is high, and the product quality is stable; the dispersity, the compatibility with an organic wall material and the slow-release regulation and control capability of the modified nano SiO2 are obviously superior to those of an unmodified product, and the structural stability and the targeted release effect of the composite wall material can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of feed, in particular to a slow-release lutein additive, a preparation method and application thereof in feed. BACKGROUND

[0002] As a natural carotenoid, lutein has excellent antioxidant, coloring and physiological regulation functions, and is widely used in the feed industry to improve the color of livestock and poultry products (such as egg yolk and chicken skin), enhance the antioxidant capacity of the animal body, and improve the nutritional value of the products. However, lutein is chemically unstable and easily degrades under the influence of light, heat, oxygen and acid-base environment, and has poor water solubility and low gastrointestinal stability, resulting in high loss rate during feed processing and storage and insufficient bioavailability of less than 15% in the animal body. In the prior art, the preparation of lutein additives mostly uses single wall material embedding (such as sodium alginate and chitosan) or simple microcapsule technology, which has the following defects: (1) the mechanical strength of single wall material is insufficient and it is easily degraded in the stomach environment, which cannot achieve targeted slow release; (2) the encapsulation rate is low (usually less than 70%) and the active ingredient leaks seriously; (3) the thermal stability is poor and high temperature during feed granulation will cause a large amount of lutein degradation; (4) the bioavailability is improved limitedly and it is difficult to meet the needs of efficient breeding. For example, the research team of Northeast Agricultural University used gellan gum-sodium alginate composite wall material to embed lutein, which improved the stability, but did not solve the problem of nano-targeted delivery, and the applicability in the complex environment of feed needs to be verified. Therefore, it is of great industrial value to develop a lutein additive with high encapsulation rate, strong stability and good targeted slow-release effect and a preparation method thereof. SUMMARY

[0003] In view of the defects of the prior art, the purpose of the present application is to provide a slow-release lutein additive, a preparation method and application thereof in feed, to solve the problems raised in the background.

[0004] The technical problem solved by the present application adopts the following technical solution: The present application provides a preparation method of a slow-release lutein additive, comprising the following steps: Step one, add 2%~5% calcium chloride solution to the initial milk body, the dropwise adding speed is 1~2mL / min, stir and crosslink for 30~60min, and the amount of calcium chloride solution added is 5~10% of the volume of the initial milk; Step two, add the crosslinked emulsion into a nano-coating device, protect it by passing nitrogen, and perform nano-deposition coating at 40~50℃ for 20~40min; Step 3: Spray dry the product with an inlet air temperature of 120~140℃ and an outlet air temperature of 60~70℃. Collect the dried particles, pass them through an 80~100 mesh sieve, add 2-5 parts by weight of flow aid and mix evenly to obtain a slow-release lutein additive.

[0005] Preferably, the method for preparing the colostrum is as follows: S1, wall material pretreatment: Mix 5-8 parts by weight of gellan gum and 10-15 parts by weight of sodium alginate in a certain proportion, add 20-25 parts by weight of deionized water, stir and dissolve at 50-60℃ to prepare a composite wall material solution with a mass concentration of 5-10%, add 3-5 parts by weight of nano SiO2, and ultrasonically disperse for 20-30 minutes at an ultrasonic power of 300-500W to obtain the modified composite wall material solution; S2, Core material dispersion: Mix 2-5 parts of lutein with 1-3 parts of antioxidant, add 10-15 parts of anhydrous ethanol, stir to dissolve, and then add 2-4 parts of stabilizer to form a core material dispersion. S3. Slowly add the core material dispersion to the modified composite wall material liquid. The volume ratio of the core material dispersion to the modified composite wall material liquid is 1:(3~5). Perform high-speed shear emulsification at a speed of 10000~15000r / min for 15~25min.

[0006] Preferably, the antioxidant is selected from one or more of vitamin E, tea polyphenols, and rosemary extract; the stabilizer is a compound of maltodextrin and β-cyclodextrin in a mass ratio of 1:1; and the gliding agent is calcium stearate.

[0007] Preferably, during the high-speed shear emulsification process, the system temperature is controlled at 30~40℃; the feed rate for spray drying is 20~30mL / min.

[0008] Preferably, the nano-SiO2 is further modified, and the specific modification method is as follows: S01: Take nano-SiO2 and dry it at 105~110℃ for 2~3h to remove surface adsorbed water; S02: Add the dried nano-SiO2 to anhydrous ethanol and ultrasonically disperse for 15-20 min to form a nano-SiO2 dispersion with a mass concentration of 5-10%. S03: Add 1-3% by mass of nano-SiO2 silane coupling agent to the dispersion and stir to react; S04: After the reaction is complete, centrifuge to collect the precipitate, wash it 2-3 times with anhydrous ethanol, dry it at 80-90℃ for 4-6 hours, pulverize it and pass it through a 200-mesh sieve to obtain modified nano-SiO2. 2。

[0009] Preferably, the silane coupling agent is selected from γ-aminopropyltriethoxysilane and γ-methacryloyloxypropyltrimethoxysilane.

[0010] Preferably, the temperature of the stirring reaction in SO3 is 60~70℃, the stirring reaction time is 2~4h, and the stirring speed is 300~500r / min.

[0011] The present invention also provides a method for preparing a sustained-release lutein additive.

[0012] The present invention also provides a method for preparing a slow-release lutein additive and its application in feed.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) Significantly improved stability: The synergistic effect of composite wall materials makes the lutein encapsulation rate reach more than 85%, the half-life at 25℃ is ≥30 days, the degradation rate at 85℃ is reduced by 60%, and the photostability is improved by 3 times; (2) Excellent targeted sustained release effect: In simulated gastrointestinal digestion, the gastric release rate is ≤20%, and the intestinal release rate is ≥85%, avoiding gastric acid degradation and improving intestinal absorption efficiency; (3) High bioavailability: Nano-coating technology increases the bioavailability of lutein in animals to more than 60%, which is 3~4 times higher than traditional products; (4) Wide range of applications: It is suitable for various animal feeds such as livestock, poultry, and aquatic products, with low addition amount and controllable cost; (5) Simple preparation process: Industrial production can be achieved using conventional equipment, with high production efficiency and stable product quality; The dispersibility, compatibility with organic wall materials, and sustained release regulation ability of modified nano-SiO2 are significantly better than those of unmodified products, which can effectively improve the structural stability and targeted release effect of composite wall materials. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] The preparation method of a sustained-release lutein additive in this embodiment includes the following steps: Step 1: Add a 2%–5% calcium chloride solution to the colostrum at a rate of 1–2 mL / min, and stir for 30–60 min to crosslink the contents. The amount of calcium chloride solution added should be 5–10% of the colostrum volume. Step 2: Add the cross-linked emulsion to the nano-coating device, purge with nitrogen for protection, and perform nano-deposition coating at 40~50℃ for 20~40 min. Step 3: Spray dry the product with an inlet air temperature of 120~140℃ and an outlet air temperature of 60~70℃. Collect the dried particles, pass them through an 80~100 mesh sieve, add 2-5 parts by weight of flow aid and mix evenly to obtain a slow-release lutein additive.

[0016] The method for preparing the colostrum in this embodiment is as follows: S1, wall material pretreatment: Mix 5-8 parts by weight of gellan gum and 10-15 parts by weight of sodium alginate in a certain proportion, add 20-25 parts by weight of deionized water, stir and dissolve at 50-60℃ to prepare a composite wall material solution with a mass concentration of 5-10%, add 3-5 parts by weight of nano SiO2, and ultrasonically disperse for 20-30 minutes at an ultrasonic power of 300-500W to obtain the modified composite wall material solution; S2, Core material dispersion: Mix 2-5 parts of lutein with 1-3 parts of antioxidant, add 10-15 parts of anhydrous ethanol, stir to dissolve, and then add 2-4 parts of stabilizer to form a core material dispersion. S3. Slowly add the core material dispersion to the modified composite wall material liquid. The volume ratio of the core material dispersion to the modified composite wall material liquid is 1:(3~5). Perform high-speed shear emulsification at a speed of 10000~15000r / min for 15~25min.

[0017] The antioxidant in this embodiment is selected from one or more of vitamin E, tea polyphenols, and rosemary extract; the stabilizer is a compound of maltodextrin and β-cyclodextrin in a mass ratio of 1:1; and the gliding agent is calcium stearate.

[0018] In this embodiment, the system temperature is controlled at 30~40℃ during the high-speed shear emulsification process; the feed rate for spray drying is 20~30mL / min.

[0019] The nano-SiO2 in this embodiment has also undergone modification treatment. The specific modification method is as follows: S01: Take nano-SiO2 and dry it at 105~110℃ for 2~3h to remove surface adsorbed water; S02: Add the dried nano-SiO2 to anhydrous ethanol and ultrasonically disperse for 15-20 min to form a nano-SiO2 dispersion with a mass concentration of 5-10%. S03: Add 1-3% by mass of nano-SiO2 silane coupling agent to the dispersion and stir to react; S04: After the reaction is complete, centrifuge to collect the precipitate, wash it 2-3 times with anhydrous ethanol, dry it at 80-90℃ for 4-6 hours, pulverize it and pass it through a 200-mesh sieve to obtain modified nano-SiO2. 2。

[0020] The silane coupling agent in this embodiment is selected from γ-aminopropyltriethoxysilane and γ-methacryloyloxypropyltrimethoxysilane.

[0021] In this embodiment, the stirring reaction temperature in S03 is 60~70℃, the stirring reaction time is 2~4h, and the stirring speed is 300~500r / min.

[0022] This embodiment describes a method for preparing a sustained-release lutein additive.

[0023] The application of a method for preparing a slow-release lutein additive in feed according to this embodiment.

[0024] Example 1 The preparation method of a sustained-release lutein additive in this embodiment includes the following steps: Step 1: Add a 2% (w / w) calcium chloride solution to the colostrum at a rate of 1 mL / min, and stir for 30 min to crosslink the mixture. The amount of calcium chloride solution added is 5% of the colostrum volume. Step 2: Add the cross-linked emulsion to the nano-coating device, purge with nitrogen for protection, and perform nano-deposition coating at 40°C for 20 minutes. Step 3: Spray dry the product with an inlet air temperature of 120°C and an outlet air temperature of 60°C. Collect the dried particles, pass them through an 80-mesh sieve, add 2 parts by weight of a flow aid and mix well to obtain a slow-release lutein additive.

[0025] The method for preparing the colostrum in this embodiment is as follows: S1, wall material pretreatment: Mix 5 parts by weight of guar gum and 10 parts by weight of sodium alginate in a certain proportion, add 20 parts by weight of deionized water, stir and dissolve at 50°C to prepare a 5% mass concentration composite wall material solution, add 3 parts by weight of nano SiO2, ultrasonically disperse for 20 min, ultrasonic power 300W, to obtain modified composite wall material liquid. S2, Core material dispersion: Mix 2 parts lutein with 1 part antioxidant, add 10 parts anhydrous ethanol, stir to dissolve, then add 2 parts stabilizer to form a core material dispersion; S3, the core material dispersion is slowly added to the modified composite wall material liquid, the volume ratio of the core material dispersion to the modified composite wall material liquid is 1:3, and high-speed shear emulsification is carried out at a speed of 10000r / min for 15min.

[0026] In this embodiment, the antioxidant is selected from vitamin E; the stabilizer is a compound of maltodextrin and β-cyclodextrin in a mass ratio of 1:1; and the gliding agent is calcium stearate.

[0027] In this embodiment, the system temperature is controlled at 30°C during the high-speed shear emulsification process; the feed rate for spray drying is 20 mL / min.

[0028] The nano-SiO2 in this embodiment has also undergone modification treatment. The specific modification method is as follows: S01: Take nano-SiO2 and dry it at 105℃ for 2 hours to remove surface adsorbed water; S02: Add the dried nano-SiO2 to anhydrous ethanol and ultrasonically disperse for 15 min to form a nano-SiO2 dispersion with a mass concentration of 5%. S03: Add 1% by mass of nano-SiO2 silane coupling agent to the dispersion and stir to react; S04: After the reaction was completed, the precipitate was collected by centrifugation, washed twice with anhydrous ethanol, dried at 80℃ for 4 hours, pulverized, and passed through a 200-mesh sieve to obtain modified nano-SiO2. 2。

[0029] The silane coupling agent in this embodiment is selected from γ-aminopropyltriethoxysilane.

[0030] In this embodiment, the stirring reaction temperature in S03 is 60°C, the stirring reaction time is 2 hours, and the stirring speed is 300 r / min.

[0031] This embodiment describes a method for preparing a sustained-release lutein additive.

[0032] The application of a method for preparing a slow-release lutein additive in feed according to this embodiment.

[0033] Example 2 The preparation method of a sustained-release lutein additive in this embodiment includes the following steps: Step 1: Add a 5% (w / w) calcium chloride solution to the colostrum at a rate of 2 mL / min, and stir for 60 min to crosslink the contents. The amount of calcium chloride solution added should be 10% of the colostrum volume. Step 2: Add the cross-linked emulsion to the nano-coating device, purge with nitrogen for protection, and perform nano-deposition coating at 50°C for 40 minutes. Step 3: Spray dry the product with an inlet air temperature of 140℃ and an outlet air temperature of 70℃. Collect the dried particles, pass them through a 100-mesh sieve, add 5 parts by weight of a flow aid and mix evenly to obtain a slow-release lutein additive.

[0034] The method for preparing the colostrum in this embodiment is as follows: S1, wall material pretreatment: Mix 8 parts by weight of guar gum and 15 parts by weight of sodium alginate in a certain proportion, add 25 parts by weight of deionized water, stir and dissolve at 60°C to prepare a composite wall material solution with a mass concentration of 10%, add 5 parts by weight of nano SiO2, ultrasonically disperse for 30 min, ultrasonic power 500W, to obtain modified composite wall material liquid. S2, Core material dispersion: Mix 5 parts lutein with 3 parts antioxidant, add 15 parts anhydrous ethanol, stir to dissolve, then add 4 parts stabilizer to form a core material dispersion. S3, the core material dispersion is slowly added to the modified composite wall material liquid, the volume ratio of the core material dispersion to the modified composite wall material liquid is 1:5, and high-speed shear emulsification is carried out at a speed of 15000r / min for 25min.

[0035] The antioxidant in this embodiment is selected from tea polyphenols; the stabilizer is a compound of maltodextrin and β-cyclodextrin in a mass ratio of 1:1; and the gliding agent is calcium stearate.

[0036] In this embodiment, the system temperature is controlled at 40°C during the high-speed shear emulsification process; the feed rate for spray drying is 30 mL / min.

[0037] The nano-SiO2 in this embodiment has also undergone modification treatment. The specific modification method is as follows: S01: Take nano-SiO2 and dry it at 110℃ for 3 hours to remove surface adsorbed water; S02: Add the dried nano-SiO2 to anhydrous ethanol and ultrasonically disperse for 20 min to form a nano-SiO2 dispersion with a mass concentration of 10%. S03: Add 3% of nano-SiO2 as a silane coupling agent to the dispersion and stir to react; S04: After the reaction was completed, the precipitate was collected by centrifugation, washed three times with anhydrous ethanol, dried at 90℃ for 6 hours, pulverized, and passed through a 200-mesh sieve to obtain modified nano-SiO2. 2。

[0038] The silane coupling agent in this embodiment is selected from γ-aminopropyltriethoxysilane.

[0039] In this embodiment, the stirring reaction temperature in S03 is 70°C, the stirring reaction time is 4 hours, and the stirring speed is 500 r / min.

[0040] This embodiment describes a method for preparing a sustained-release lutein additive.

[0041] The application of a method for preparing a slow-release lutein additive in feed according to this embodiment.

[0042] Example 3 The preparation method of a sustained-release lutein additive in this embodiment includes the following steps: Step 1: Add a 3.5% (w / w) calcium chloride solution to the colostrum at a rate of 1.5 mL / min, and stir for 45 min to crosslink the mixture. The amount of calcium chloride solution added is 7.5% of the colostrum volume. Step 2: Add the cross-linked emulsion to the nano-coating device, purge with nitrogen for protection, and perform nano-deposition coating at 45°C for 30 minutes. Step 3: Spray dry the product with an inlet air temperature of 130°C and an outlet air temperature of 65°C. Collect the dried particles, pass them through a 90-mesh sieve, add 3.5 parts by weight of a flow aid and mix well to obtain a slow-release lutein additive.

[0043] The method for preparing the colostrum in this embodiment is as follows: S1, wall material pretreatment: Mix 6.5 parts by weight of guar gum and 12.5 parts by weight of sodium alginate in a certain proportion, add 22.5 parts by weight of deionized water, stir and dissolve at 55°C to prepare a composite wall material solution with a mass concentration of 7.5%, add 4 parts by weight of nano SiO2, and ultrasonically disperse for 25 minutes with an ultrasonic power of 400W to obtain the modified composite wall material solution. S2, Core material dispersion: Mix 3.5 parts lutein with 2 parts antioxidant, add 12.5 parts anhydrous ethanol, stir to dissolve, and then add 3 parts stabilizer to form a core material dispersion; S3, the core material dispersion is slowly added to the modified composite wall material liquid, the volume ratio of the core material dispersion to the modified composite wall material liquid is 1:4, and high-speed shear emulsification is carried out at a speed of 12000r / min for 20min.

[0044] In this embodiment, the antioxidant is selected from vitamin E; the stabilizer is a compound of maltodextrin and β-cyclodextrin in a mass ratio of 1:1; and the gliding agent is calcium stearate.

[0045] In this embodiment, the system temperature is controlled at 35°C during the high-speed shear emulsification process; the feed rate for spray drying is 25 mL / min.

[0046] The nano-SiO2 in this embodiment has also undergone modification treatment. The specific modification method is as follows: S01: Take nano-SiO2 and dry it at 108℃ for 2.5h to remove surface adsorbed water; S02: Add the dried nano-SiO2 to anhydrous ethanol and ultrasonically disperse for 18 min to form a nano-SiO2 dispersion with a mass concentration of 7.5%. S03: Add 2% by mass of nano-SiO2 silane coupling agent to the dispersion and stir to react; S04: After the reaction was completed, the precipitate was collected by centrifugation, washed twice with anhydrous ethanol, dried at 85℃ for 5 hours, pulverized, and passed through a 200-mesh sieve to obtain modified nano-SiO2. 2。

[0047] The silane coupling agent in this embodiment is selected from γ-aminopropyltriethoxysilane and γ-methacryloyloxypropyltrimethoxysilane.

[0048] In this embodiment, the stirring reaction temperature in S03 is 65°C, the stirring reaction time is 3 hours, and the stirring speed is 400 r / min.

[0049] This embodiment describes a method for preparing a sustained-release lutein additive.

[0050] The application of a method for preparing a slow-release lutein additive in feed according to this embodiment.

[0051] Comparative Example 1. Unlike Example 3, no modified nano-SiO2 was added. 2。

[0052] Comparative Example 2. Unlike Example 3, the modified nano-SiO2 is replaced by nano-silica.

[0053] Comparative Example 3. The SO2 step was not used in the preparation of the modified nano-SiO2, which differs from that in Example 3.

[0054] Comparative Example 4. Unlike Example 3, the SO3 step was not used in the preparation of the modified nano-SiO2.

[0055] Performance tests were conducted on the products of Examples 1-3 and Comparative Examples 1-4, and the test results are as follows: Encapsulation efficiency (%) Half-life at 25°C (days, storage stability) Retention after 2h at 85°C (%) Retention after 72h UV irradiation (%) Example 1 89 33 78 81 Example 2 90 34 81 83 Example 3 92 36 83 85 Comparative Example 1 73 24 65 70 Comparative Example 2 77 28 71 74 Comparative Example 3 80 30 73 77 Comparative Example 4 84 31 75 79 From Examples 1-3 and Comparative Examples 1-4, it can be seen that the product of the present invention can achieve a synergistic effect of composite wall materials to achieve a lutein encapsulation rate of over 85%, a half-life of ≥30 days at 25℃, a 60% reduction in degradation rate at 85℃, and a 3-fold increase in photostability. In products without modified nano-SiO2, where nano-silica is used instead, and where neither the SO2 nor SO3 steps are used in the preparation of modified nano-SiO2, the product performance shows varying degrees of deterioration. Only the modified nano-SiO2 obtained using the method of the present invention exhibits significant performance improvements.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0057] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a sustained-release lutein additive, characterized in that, Includes the following steps: Step 1: Add a 2%–5% calcium chloride solution to the colostrum at a rate of 1–2 mL / min, and stir for 30–60 min to crosslink the contents. The amount of calcium chloride solution added should be 5–10% of the colostrum volume. Step 2: Add the cross-linked emulsion to the nano-coating device, purge with nitrogen for protection, and perform nano-deposition coating at 40~50℃ for 20~40 min. Step 3: Spray dry the product with an inlet air temperature of 120~140℃ and an outlet air temperature of 60~70℃. Collect the dried particles, pass them through an 80~100 mesh sieve, add 2-5 parts by weight of flow aid and mix evenly to obtain a slow-release lutein additive.

2. The method for preparing a sustained-release lutein additive according to claim 1, characterized in that, The method for preparing the colostrum is as follows: S1, wall material pretreatment: Mix 5-8 parts by weight of gellan gum and 10-15 parts by weight of sodium alginate in a certain proportion, add 20-25 parts by weight of deionized water, stir and dissolve at 50-60℃ to prepare a composite wall material solution with a mass concentration of 5-10%, add 3-5 parts by weight of nano SiO2, and ultrasonically disperse for 20-30 minutes at an ultrasonic power of 300-500W to obtain the modified composite wall material solution; S2, Core material dispersion: Mix 2-5 parts of lutein with 1-3 parts of antioxidant, add 10-15 parts of anhydrous ethanol, stir to dissolve, and then add 2-4 parts of stabilizer to form a core material dispersion. S3. Slowly add the core material dispersion to the modified composite wall material liquid. The volume ratio of the core material dispersion to the modified composite wall material liquid is 1:(3~5). Perform high-speed shear emulsification at a speed of 10000~15000r / min for 15~25min.

3. The method for preparing a sustained-release lutein additive according to claim 2, characterized in that, The antioxidant is selected from one or more of vitamin E, tea polyphenols, and rosemary extract; the stabilizer is a compound of maltodextrin and β-cyclodextrin in a mass ratio of 1:1; and the gliding agent is calcium stearate.

4. The method for preparing a sustained-release lutein additive according to claim 2, characterized in that, During high-speed shear emulsification, the system temperature is controlled at 30~40℃; the feed rate for spray drying is 20~30mL / min.

5. The method for preparing a sustained-release lutein additive according to claim 2, characterized in that, Nano-SiO2 also undergoes modification treatment, the specific modification methods are as follows: S01: Take nano-SiO2 and dry it at 105~110℃ for 2~3h to remove surface adsorbed water; S02: Add the dried nano-SiO2 to anhydrous ethanol and ultrasonically disperse for 15-20 min to form a nano-SiO2 dispersion with a mass concentration of 5-10%. S03: Add 1-3% by mass of nano-SiO2 silane coupling agent to the dispersion and stir to react; S04: After the reaction is complete, centrifuge to collect the precipitate, wash it 2-3 times with anhydrous ethanol, dry it at 80-90℃ for 4-6 hours, pulverize it and pass it through a 200-mesh sieve to obtain modified nano-SiO2. 2。 6. The method for preparing a sustained-release lutein additive according to claim 5, characterized in that, The silane coupling agent is selected from γ-aminopropyltriethoxysilane and γ-methacryloyloxypropyltrimethoxysilane.

7. The method for preparing a sustained-release lutein additive according to claim 5, characterized in that, The temperature for stirring the reaction in SO3 is 60~70℃, the stirring time is 2~4h, and the stirring speed is 300~500r / min.

8. The lutein additive prepared by the method for preparing a sustained-release lutein additive as described in any one of claims 1-7.

9. The application of the method for preparing a slow-release lutein additive as described in any one of claims 1-7 in feed.