Rumen bypass choline chloride and production process thereof

Abstract

The present invention proposes a rumen bypass choline chloride and a production process thereof, and belongs to the field of rumen bypass technology. The present invention comprises the following steps: S1. preparing carboxylated chitosan; S2. preparing carboxylated chitosan-silk fibroin peptide condensate; S3. preparing pH-responsive acrylic material; S4. coating pH-responsive acrylic material with choline chloride; S5. coating the surface with a layer of carboxylated chitosan-silk fibroin peptide condensate. The rumen bypass choline chloride prepared by the present invention can successfully pass through the rumen, avoid being damaged and degraded, swell and degrade in the true stomach, expose the pellet core, and then be absorbed by the small intestine, which greatly improves the absorption rate of choline chloride by dairy cows, thereby promoting lactation well, and has a good effect of promoting lactation for dairy cows in the early and peak lactation stages, and has broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of rumen bypass, and in particular to rumen bypass choline chloride and a production process thereof. Background Art

[0002] Choline is a B vitamin, and its chemical name is hydroxyethyltrimethylamine. It has many biological functions, including: a component of phospholipids, participating in the formation of lecithin and sphingomyelin; an unstable methyl group donor; playing an important role in regulating liver fat metabolism; and being the main component of acetylcholine synthesis. At present, choline has been used as a feed additive in complete feeds for pigs and poultry and concentrates for ruminants. It is an indispensable additive that not only has a significant effect on the growth, development, and performance improvement of livestock and poultry, but also can enhance the physical fitness and disease resistance of livestock and poultry.

[0003] Choline is a colorless liquid at room temperature, which is hygroscopic, alkaline and viscous. Choline chloride is the hydrochloride of choline. The molecule has a polar tendency and easily absorbs moisture in the air and deliquesces. Choline chloride is often used in the feed industry to replace choline. Compared with choline, choline chloride has higher stability, its aqueous solution is neutral, and has less irritation to animal tissues. However, choline chloride crystals are highly hygroscopic and easy to agglomerate, which brings inconvenience to the processing, transportation and storage of feed. Choline chloride has a destructive effect on other vitamins, especially in the presence of metal elements, it has a destructive effect on vitamins A, D3, E, and K3, so it should not be mixed with vitamin premixes.

[0004] Ruminants can synthesize choline in their bodies to meet the needs of animals. Although choline is generally not deficient, the choline in the body cannot meet the needs of animals during pregnancy and lactation. Therefore, supplementing sufficient choline can save the part of methionine consumed for synthesizing choline, so that more methionine can be used for milk production. At the same time, in the rumen of ruminants, choline will be degraded into acetaldehyde and trimethylamine by rumen microorganisms, and further degraded into methane, which will be discharged with the animal's belching. The degradation rate of choline is very high, among which the degradation rate of choline chloride is as high as 98.6%, so unprotected choline chloride is often difficult to pass through the rumen. Therefore, how to reduce the degradation rate of choline chloride in the rumen through rumen protection technology so that it can safely pass through the rumen to reach the digestive tract after the rumen and be absorbed and utilized by the body is a key technical problem that needs to be solved urgently.

[0005] In order to solve the above problems, the main coating technology is currently used. By selecting different types of coating materials to coat choline chloride, choline chloride is protected as much as possible from being degraded by microorganisms in the rumen, and effectively released in the digestive tract after the rumen to be absorbed and utilized by the body. In the preparation of rumen bypass products, granulation is the basis of coating. The shape, bulk density and particle size of the product particles will affect the effect of the next step of coating. At present, most of the particles are made into columnar or irregular shapes by cutting. The shape of the product has a great influence on the coating effect. Choline chloride is lost in the rumen or due to factors such as expensive coating materials and complicated processing technology, enterprises are unable to produce on a large scale, which ultimately makes it difficult to promote and apply rumen bypass choline chloride products in farms. Summary of the invention

[0006] The purpose of the present invention is to provide a rumen-bypass choline chloride and a production process thereof, which can successfully pass through the rumen and avoid being damaged and degraded, swell and degrade in the true stomach to expose the pellet core, and then be absorbed by the small intestine, thereby greatly improving the absorption rate of choline chloride by dairy cows, thereby promoting lactation well, having a good effect of promoting lactation for dairy cows in the early and peak lactation periods, and having broad application prospects.

[0007] The technical solution of the present invention is achieved in this way:

[0008] The present invention provides a production process of rumen bypass choline chloride, comprising the following steps:

[0009] S1. Preparation of carboxylated chitosan;

[0010] S2. Preparation of carboxylated chitosan-silk fibroin peptide condensate;

[0011] S3. Preparation of pH responsive acrylic acid materials;

[0012] S4. Choline chloride coated pH responsive acrylic material;

[0013] S5. The surface is then coated with a layer of carboxylated chitosan-silk fibroin peptide condensate.

[0014] As a further improvement of the present invention, the following steps are included:

[0015] S1. Preparation of carboxylated chitosan: dissolving chitosan in acid solution, adding pyruvic acid, stirring the reaction, adding sodium borohydride, continuing the reaction, adding ethanol to terminate the reaction, filtering, washing, and drying to obtain carboxylated chitosan;

[0016] S2. Preparation of carboxylated chitosan-silk fibroin peptide condensate: Activate the carboxylated chitosan obtained in step S1 with N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and then react with silk fibroin peptide to obtain carboxylated chitosan-silk fibroin peptide condensate;

[0017] S3. Preparation of pH responsive polyacrylic acid material: adding an initiator, a complexing agent, a monomer, and cuprous bromide to tetrahydrofuran, stirring evenly, adding a catalyst under the protection of an inert gas, heating and stirring to react, filtering, washing, and drying to obtain a pH responsive polyacrylic acid material;

[0018] S4. Preparation of pH-responsive polyacrylic acid-coated choline chloride microspheres: dissolving the pH-responsive polyacrylic acid material obtained in step S3 in dichloromethane, stirring and mixing to obtain an oil phase; dissolving choline chloride in water, adding an emulsifier, stirring and mixing to obtain an aqueous phase, and dropping the aqueous phase into the oil phase, emulsifying, centrifuging, washing, and drying to obtain pH-responsive polyacrylic acid-coated choline chloride microspheres;

[0019] S5. Re-coating of carboxylated chitosan-silk fibroin peptide condensate: dissolve the carboxylated chitosan-silk fibroin peptide condensate obtained in step S2 in water, add the pH-responsive polyacrylic acid-coated choline chloride microspheres and emulsifier obtained in step S4, stir and mix evenly, drop into a dichloromethane solution of genipin, emulsify, cross-link, centrifuge, wash, and dry to obtain rumen-permeable choline chloride.

[0020] As a further improvement of the present invention, the mass ratio of chitosan, pyruvic acid and sodium borohydride in step S1 is 10:4-6:2-3, the acid solution is 1-3wt% acetic acid or lactic acid solution, the stirring reaction temperature is 35-40°C, the time is 10-15h, the continued reaction time is 4-7h, and ethanol is added until the ethanol content of the system is 70-80wt%.

[0021] As a further improvement of the present invention, the mass ratio of carboxylated chitosan, N-hydroxysuccinimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and silk fibroin peptide in step S2 is 10:3-5:5-7:4-6, the activation temperature is 0-4°C, the time is 20-40min, and the reaction time is 12-15h.

[0022] As a further improvement of the present invention, the mass ratio of the initiator, complexing agent, monomer, cuprous bromide and catalyst in step S3 is 0.3-0.5:1-2:80-110:0.01-0.02:0.1-0.2, the initiator is selected from at least one of sodium persulfate, potassium persulfate and ammonium persulfate, the complexing agent is N,N,N',N",N"-pentamethyldiethylenetriamine, the monomer is a mixture of methacrylic acid, methyl acrylate and methacrylic acid-N,N'-dimethylethyl ester, the mass ratio is 10-15:12-14:7-10, and the catalyst is cupric bromide; the temperature of the heating and stirring reaction is 55-65°C, and the time is 2-4h.

[0023] As a further improvement of the present invention, the mass ratio of the pH-responsive polyacrylic acid material, choline chloride and emulsifier in step S4 is 12-15:10-12:1-2, and the emulsifier is selected from at least one of Tween-20, Tween-40, Tween-60 and Tween-80.

[0024] As a further improvement of the present invention, the mass ratio of the carboxylated chitosan-silk fibroin peptide condensate, the pH-responsive polyacrylic acid-coated choline chloride microspheres, and the emulsifier in step S5 is 17-20:12-15:1-2, the emulsifier is selected from at least one of Tween-20, Tween-40, Tween-60, and Tween-80, the content of genipin in the dichloromethane solution containing genipin is 1-2wt%, and the time of the cross-linking reaction is 30-60min.

[0025] As a further improvement of the present invention, the present invention specifically comprises the following steps:

[0026] S1. Preparation of carboxylated chitosan: 10 parts by weight of chitosan was dissolved in 200 parts by weight of 1-3wt% acetic acid or lactic acid solution, 4-6 parts by weight of pyruvic acid was added, stirred at 35-40°C for 10-15h, 2-3 parts by weight of sodium borohydride was added, the reaction was continued for 4-7h, ethanol was added until the ethanol content of the system was 70-80wt%, the reaction was terminated, filtered, washed, and dried to obtain carboxylated chitosan;

[0027] S2. Preparation of carboxylated chitosan-silk fibroin peptide condensate: add 10 parts by weight of the carboxylated chitosan obtained in step S1 to 200 parts by weight of water, add 3-5 parts by weight of N-hydroxysuccinimide and 5-7 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, activate with stirring at 0-4°C for 20-40 min, add 4-6 parts by weight of silk fibroin peptide, react with stirring at room temperature for 12-15 h, add ethanol until the ethanol content of the system is 70-80wt%, terminate the reaction, filter, wash, and dry to obtain carboxylated chitosan-silk fibroin peptide condensate;

[0028] S3. Preparation of pH responsive polyacrylic acid material: 0.3-0.5 parts by weight of initiator, 1-2 parts by weight of complexing agent N,N,N',N",N"-pentamethyldiethylenetriamine, 80-110 parts by weight of monomer, 0.01-0.02 parts by weight of cuprous bromide are mixed and added to 500 parts by weight of tetrahydrofuran, stirred evenly, and 0.1-0.2 parts by weight of catalyst copper bromide is added under nitrogen protection, heated to 55-65°C, stirred for reaction for 2-4h, filtered, washed, and dried to obtain pH responsive polyacrylic acid material;

[0029] The monomer is a mixture of methacrylic acid, methyl acrylate, and N,N'-dimethylethyl methacrylate, with a mass ratio of 10-15:12-14:7-10;

[0030] S4. Preparation of pH-responsive polyacrylic acid-coated choline chloride microspheres: dissolve 12-15 parts by weight of the pH-responsive polyacrylic acid material obtained in step S3 in 500 parts by weight of dichloromethane, stir and mix evenly to obtain an oil phase; dissolve 10-12 parts by weight of choline chloride in 200 parts by weight of water, add 1-2 parts by weight of an emulsifier, stir and mix evenly to obtain an aqueous phase, dropwise add the aqueous phase into the oil phase, emulsify, centrifuge, wash, and freeze-dry to obtain pH-responsive polyacrylic acid-coated choline chloride microspheres;

[0031] S5. Re-coating of carboxylated chitosan-silk fibroin peptide condensate: dissolve 17-20 parts by weight of the carboxylated chitosan-silk fibroin peptide condensate obtained in step S2 in 200 parts by weight of water, add 12-15 parts by weight of the pH-responsive polyacrylic acid-coated choline chloride microspheres obtained in step S4 and 1-2 parts by weight of an emulsifier, stir and mix evenly, drop into 500 parts by weight of a dichloromethane solution containing 1-2wt% of genipin, emulsify, cross-link for 30-60 minutes, centrifuge, wash, and dry to obtain rumen-bypass choline chloride.

[0032] The present invention further protects rumen bypass choline chloride produced by the above production process.

[0033] The present invention further protects the use of the rumen bypass choline chloride in preparing products for promoting lactation, growth, development, and improving immunity and disease resistance of poultry.

[0034] The present invention has the following beneficial effects:

[0035] The rumen-pass coating technology achieves the effect of rumen-passing by coating the surface of choline chloride (core material) with one or more layers of protective materials (wall materials) that are stable in the rumen and released in the abomasum. The use of rumen-pass coating technology can effectively alleviate the degradation of choline chloride by rumen microorganisms, thereby improving the utilization rate of nutrients, reducing feeding costs, and further reducing the amount of choline chloride in feed, reducing feed usage, reducing feeding costs, and improving its production performance.

[0036] The rumen-bypass choline chloride of the present invention can effectively increase milk production, and has a good effect of promoting lactation for dairy cows in the early and peak lactation periods. At the same time, the rumen-bypass technology is adopted, and anti-rumen degradation substances are used to perform multi-layer coating on the active ingredients, so that the rumen-bypass choline chloride is perfectly developed, which ensures that the product can successfully pass through the rumen, greatly improves the absorption rate of choline chloride by dairy cows, and plays a better regulatory role.

[0037] The present invention prepares carboxylated chitosan, which solves the disadvantage of chitosan being poorly soluble in water on the one hand, and on the other hand, the carboxylated chitosan-silk fibroin peptide condensate formed by the prepared carboxylated chitosan and silk fibroin has good amphiphilicity and good emulsification, and can form a firm and stable shell layer to protect the contained material from being degraded and destroyed in the rumen. In the acidic true stomach environment, the chitosan coating layer swells and degrades, exposing the pellet core, which is then absorbed by the small intestine.

[0038] The polyacrylic acid material prepared by the present invention has good pH responsiveness, and different physical and chemical property changes will occur at different pH values. Under higher pH conditions (rumen), the polyacrylic acid polymer will present a condensation state or a gel state, while under lower pH conditions (abomasum), it will present a swelling state, thereby releasing the inclusions.

[0039] The rumen-bypass choline chloride prepared by the invention can successfully pass through the rumen and avoid being damaged and degraded, swells and degrades in the true stomach to expose the pellet core, and is subsequently absorbed by the small intestine, thereby greatly improving the absorption rate of choline chloride by dairy cows, thereby promoting lactation well, having a good effect of promoting lactation for dairy cows in the early and peak lactation stages, and having broad application prospects. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Chitosan, industrial grade, was purchased from Shandong Yatu Biotechnology Co., Ltd.; silk fibroin peptide, CAS: 96690-41-4, was purchased from Wuhan Huaxiang Kejie Biotechnology Co., Ltd.

[0042] Example 1

[0043] This embodiment provides a production process of rumen bypass choline chloride, which specifically comprises the following steps:

[0044] S1. Preparation of carboxylated chitosan: 10 parts by weight of chitosan was dissolved in 200 parts by weight of 1 wt% acetic acid solution, 4 parts by weight of pyruvic acid was added, stirred at 35°C for 10 h, 2 parts by weight of sodium borohydride was added, the reaction was continued for 4 h, ethanol was added until the ethanol content of the system was 70 wt%, the reaction was terminated, filtered, washed, and dried to obtain carboxylated chitosan;

[0045] S2. Preparation of carboxylated chitosan-silk fibroin peptide condensate: add 10 parts by weight of carboxylated chitosan obtained in step S1 to 200 parts by weight of water, add 3 parts by weight of N-hydroxysuccinimide and 5 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, activate with stirring at 0°C for 20 minutes, add 4 parts by weight of silk fibroin peptide, react with stirring at room temperature for 12 hours, add ethanol until the ethanol content of the system is 70wt%, terminate the reaction, filter, wash, and dry to obtain carboxylated chitosan-silk fibroin peptide condensate;

[0046] S3. Preparation of pH responsive polyacrylic acid material: 0.3 parts by weight of sodium persulfate, 1 part by weight of complexing agent N,N,N',N",N"-pentamethyldiethylenetriamine, 80 parts by weight of monomer, and 0.01 parts by weight of cuprous bromide were mixed and added to 500 parts by weight of tetrahydrofuran, and stirred for 20 minutes. Under nitrogen protection, 0.1 parts by weight of catalyst copper bromide was added, heated to 55°C, stirred for 2 hours, filtered, washed, and dried to obtain a pH responsive polyacrylic acid material;

[0047] The monomer is a mixture of methacrylic acid, methyl acrylate, and N,N'-dimethylethyl methacrylate, with a mass ratio of 10:12:7;

[0048] S4. Preparation of pH-responsive polyacrylic acid-coated choline chloride microspheres: dissolve 12 parts by weight of the pH-responsive polyacrylic acid material obtained in step S3 in 500 parts by weight of dichloromethane, stir and mix evenly to obtain an oil phase; dissolve 10 parts by weight of choline chloride in 200 parts by weight of water, add 1 part by weight of emulsifier Tween-20, stir and mix evenly to obtain an aqueous phase, dropwise add the aqueous phase into the oil phase, emulsify at 10000 r / min for 15 min, centrifuge, wash, and freeze-dry to obtain pH-responsive polyacrylic acid-coated choline chloride microspheres;

[0049] S5. Re-coating of carboxylated chitosan-silk fibroin peptide condensate: dissolve 17 parts by weight of the carboxylated chitosan-silk fibroin peptide condensate obtained in step S2 in 200 parts by weight of water, add 12 parts by weight of pH-responsive polyacrylic acid-coated choline chloride microspheres obtained in step S4 and 1 part by weight of emulsifier Tween-20, stir and mix evenly, drop into 500 parts by weight of a dichloromethane solution containing 1 wt% of genipin, emulsify at 10,000 r / min for 15 minutes, cross-link for 30 minutes, centrifuge, wash, and dry to obtain rumen-bypass choline chloride.

[0050] Example 2

[0051] This embodiment provides a production process of rumen bypass choline chloride, which specifically comprises the following steps:

[0052] S1. Preparation of carboxylated chitosan: 10 parts by weight of chitosan was dissolved in 200 parts by weight of 3 wt% lactic acid solution, 6 parts by weight of pyruvic acid was added, stirred at 40°C for 15 h, 3 parts by weight of sodium borohydride was added, the reaction was continued for 7 h, ethanol was added until the ethanol content of the system was 80 wt%, the reaction was terminated, filtered, washed, and dried to obtain carboxylated chitosan;

[0053] S2. Preparation of carboxylated chitosan-silk fibroin peptide condensate: add 10 parts by weight of carboxylated chitosan obtained in step S1 to 200 parts by weight of water, add 5 parts by weight of N-hydroxysuccinimide and 7 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, activate with stirring at 4°C for 40 minutes, add 6 parts by weight of silk fibroin peptide, react with stirring at room temperature for 15 hours, add ethanol until the ethanol content of the system is 80wt%, terminate the reaction, filter, wash, and dry to obtain carboxylated chitosan-silk fibroin peptide condensate;

[0054] S3. Preparation of pH responsive polyacrylic acid material: 0.5 parts by weight of potassium persulfate, 2 parts by weight of complexing agent N,N,N',N",N"-pentamethyldiethylenetriamine, 110 parts by weight of monomer, and 0.02 parts by weight of cuprous bromide were mixed and added to 500 parts by weight of tetrahydrofuran, and stirred for 20 minutes. Under nitrogen protection, 0.2 parts by weight of catalyst copper bromide was added, heated to 65°C, stirred for 4 hours, filtered, washed, and dried to obtain a pH responsive polyacrylic acid material;

[0055] The monomer is a mixture of methacrylic acid, methyl acrylate, and N,N'-dimethylethyl methacrylate, with a mass ratio of 15:14:10;

[0056] S4. Preparation of pH-responsive polyacrylic acid-coated choline chloride microspheres: dissolve 15 parts by weight of the pH-responsive polyacrylic acid material obtained in step S3 in 500 parts by weight of dichloromethane, stir and mix evenly to obtain an oil phase; dissolve 12 parts by weight of choline chloride in 200 parts by weight of water, add 2 parts by weight of emulsifier Tween-40, stir and mix evenly to obtain an aqueous phase, dropwise add the aqueous phase into the oil phase, emulsify at 10000 r / min for 15 min, centrifuge, wash, and freeze-dry to obtain pH-responsive polyacrylic acid-coated choline chloride microspheres;

[0057] S5. Re-coating of carboxylated chitosan-silk fibroin peptide condensate: dissolve 20 parts by weight of the carboxylated chitosan-silk fibroin peptide condensate obtained in step S2 in 200 parts by weight of water, add 15 parts by weight of pH-responsive polyacrylic acid-coated choline chloride microspheres obtained in step S4 and 2 parts by weight of emulsifier Tween-40, stir and mix evenly, drop into 500 parts by weight of a dichloromethane solution containing 2 wt% of genipin, emulsify at 10,000 r / min for 15 minutes, cross-link for 60 minutes, centrifuge, wash, and dry to obtain rumen-bypass choline chloride.

[0058] Example 3

[0059] This embodiment provides a production process of rumen bypass choline chloride, which specifically comprises the following steps:

[0060] S1. Preparation of carboxylated chitosan: 10 parts by weight of chitosan was dissolved in 200 parts by weight of 2 wt% acetic acid solution, 5 parts by weight of pyruvic acid was added, the reaction was stirred at 37°C for 12 h, 2.5 parts by weight of sodium borohydride was added, the reaction was continued for 5 h, ethanol was added until the ethanol content of the system was 75 wt%, the reaction was terminated, filtered, washed, and dried to obtain carboxylated chitosan;

[0061] S2. Preparation of carboxylated chitosan-silk fibroin peptide condensate: add 10 parts by weight of carboxylated chitosan obtained in step S1 to 200 parts by weight of water, add 4 parts by weight of N-hydroxysuccinimide and 6 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, activate with stirring at 2°C for 30 minutes, add 5 parts by weight of silk fibroin peptide, react with stirring at room temperature for 13 hours, add ethanol until the ethanol content of the system is 75wt%, terminate the reaction, filter, wash, and dry to obtain carboxylated chitosan-silk fibroin peptide condensate;

[0062] S3. Preparation of pH responsive polyacrylic acid material: 0.4 parts by weight of ammonium persulfate, 1.5 parts by weight of complexing agent N,N,N',N",N"-pentamethyldiethylenetriamine, 95 parts by weight of monomer, and 0.015 parts by weight of cuprous bromide were mixed and added to 500 parts by weight of tetrahydrofuran, and stirred for 20 minutes. Under nitrogen protection, 0.15 parts by weight of catalyst copper bromide was added, heated to 60°C, stirred for reaction for 3 hours, filtered, washed, and dried to obtain a pH responsive polyacrylic acid material;

[0063] The monomer is a mixture of methacrylic acid, methyl acrylate, and N,N'-dimethylethyl methacrylate, with a mass ratio of 12:13:8.5;

[0064] S4. Preparation of pH-responsive polyacrylic acid-coated choline chloride microspheres: dissolve 13.5 parts by weight of the pH-responsive polyacrylic acid material obtained in step S3 in 500 parts by weight of dichloromethane, stir and mix evenly to obtain an oil phase; dissolve 11 parts by weight of choline chloride in 200 parts by weight of water, add 1.5 parts by weight of emulsifier Tween-80, stir and mix evenly to obtain an aqueous phase, dropwise add the aqueous phase to the oil phase, emulsify at 10000 r / min for 15 min, centrifuge, wash, and freeze-dry to obtain pH-responsive polyacrylic acid-coated choline chloride microspheres;

[0065] S5. Re-coating of carboxylated chitosan-silk fibroin peptide condensate: dissolve 18 parts by weight of the carboxylated chitosan-silk fibroin peptide condensate obtained in step S2 in 200 parts by weight of water, add 13 parts by weight of pH-responsive polyacrylic acid-coated choline chloride microspheres obtained in step S4 and 1.5 parts by weight of emulsifier Tween-80, stir and mix evenly, drop into 500 parts by weight of a dichloromethane solution containing 1.5 wt% of genipin, emulsify at 10,000 r / min for 15 minutes, cross-link for 45 minutes, centrifuge, wash, and dry to obtain rumen-bypass choline chloride.

[0066] Comparative Example 1

[0067] Compared with Example 3, the difference is that steps S3 and S4 are not performed.

[0068] Comparative Example 2

[0069] Compared with Example 3, the difference is that in step S5, the carboxylated chitosan-silk fibroin peptide is replaced by an equal amount of carboxylated chitosan.

[0070] Comparative Example 3

[0071] Compared with Example 3, the difference is that in step S5, the carboxylated chitosan-silk fibroin peptide is replaced by an equal amount of silk fibroin peptide.

[0072] Comparative Example 4

[0073] Compared with Example 3, the difference is that steps S1, S2 and S5 are not performed.

[0074] Test Example 1

[0075] The rumen bypassed choline chloride prepared in Examples 1-3 and Comparative Examples 1-4 was placed under different pH conditions at 39°C, and the dissolution instrument was set to paddle method 100r / min to determine the release rate of rumen bypassed choline chloride. The pH2.4 (abomasum) solution was directly prepared with hydrochloric acid; the pH5.5 (rumen 1) and pH6.6 (rumen 2) solutions were prepared by dissolving 0.072 and 0.656g of sodium hydroxide and 6.805g of potassium dihydrogen phosphate in water, respectively, and then fixed to volume in a 1000mL volumetric flask. The choline chloride content in the dissolution medium was determined by high performance liquid chromatography to determine the in vitro release rate at 0h, 4h, and 8h. The results are shown in Tables 1 to 3.

[0076] Table 1 In vitro release rate in pH 2.4 (abomasum) solution

[0077]

[0078] Table 2 In vitro release rate in pH 5.5 (rumen 1) solution

[0079]

[0080] Table 3 In vitro release rate in pH 6.6 (rumen 2) solution

[0081]

[0082] As can be seen from the above table, the rumen bypass choline chloride prepared in Examples 1-3 of the present invention has a low in vitro release rate in pH 5.5 (rumen 1) solution and pH 6.6 (rumen 2) solution, but can be fully released in pH 2.4 (abomasum) solution, and has a good rumen bypass effect.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A production process for rumen bypass choline chloride, characterized in that: The specific steps include: S1. Preparation of carboxylated chitosan: 10 parts by weight of chitosan was dissolved in 200 parts by weight of 1-3wt% acetic acid or lactic acid solution, 4-6 parts by weight of pyruvic acid was added, stirred at 35-40°C for 10-15h, 2-3 parts by weight of sodium borohydride was added, the reaction was continued for 4-7h, ethanol was added until the ethanol content of the system was 70-80wt%, the reaction was terminated, filtered, washed, and dried to obtain carboxylated chitosan; S2. Preparation of carboxylated chitosan-silk fibroin peptide condensate: add 10 parts by weight of the carboxylated chitosan obtained in step S1 to 200 parts by weight of water, add 3-5 parts by weight of N-hydroxysuccinimide and 5-7 parts by weight of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, activate with stirring at 0-4°C for 20-40 min, add 4-6 parts by weight of silk fibroin peptide, react with stirring at room temperature for 12-15 h, add ethanol until the ethanol content of the system is 70-80wt%, terminate the reaction, filter, wash, and dry to obtain carboxylated chitosan-silk fibroin peptide condensate; S3. Preparation of pH responsive polyacrylic acid material: 0.3-0.5 parts by weight of initiator, 1-2 parts by weight of complexing agent N,N,N',N",N"-pentamethyldiethylenetriamine, 80-110 parts by weight of monomer, 0.01-0.02 parts by weight of cuprous bromide are mixed and added to 500 parts by weight of tetrahydrofuran, stirred evenly, and 0.1-0.2 parts by weight of catalyst copper bromide is added under nitrogen protection, heated to 55-65°C, stirred for reaction for 2-4h, filtered, washed, and dried to obtain pH responsive polyacrylic acid material; The monomer is a mixture of methacrylic acid, methyl acrylate, and N,N'-dimethylethyl methacrylate, with a mass ratio of 10-15:12-14:7-10; S4. Preparation of pH-responsive polyacrylic acid-coated choline chloride microspheres: dissolve 12-15 parts by weight of the pH-responsive polyacrylic acid material obtained in step S3 in 500 parts by weight of dichloromethane, stir and mix evenly to obtain an oil phase; dissolve 10-12 parts by weight of choline chloride in 200 parts by weight of water, add 1-2 parts by weight of an emulsifier, stir and mix evenly to obtain an aqueous phase, dropwise add the aqueous phase into the oil phase, emulsify, centrifuge, wash, and freeze-dry to obtain pH-responsive polyacrylic acid-coated choline chloride microspheres; S5. Re-coating of carboxylated chitosan-silk fibroin peptide condensate: dissolving 17-20 parts by weight of the carboxylated chitosan-silk fibroin peptide condensate obtained in step S2 in 200 parts by weight of water, adding 12-15 parts by weight of the pH-responsive polyacrylic acid-coated choline chloride microspheres obtained in step S4 and 1-2 parts by weight of an emulsifier, stirring and mixing evenly, dropping into 500 parts by weight of a dichloromethane solution containing 1-2 wt% genipin, emulsifying, cross-linking reaction for 30-60 min, centrifuging, washing, and drying to obtain rumen-bypass choline chloride; The initiator is ammonium persulfate; The emulsifier is selected from at least one of Tween-20, Tween-40 and Tween-80.

2. Rumen bypass choline chloride obtained by the production process as claimed in claim 1.

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