Broiler chicken growth promoter based on plant extracts and preparation method thereof

Abstract

The invention relates to a broiler growth promoter based on plant extracts and a preparation method of the broiler growth promoter, and belongs to the technical field of feed additives. The preparation method of the broiler chicken growth promoter based on the plant extract comprises the following steps: mixing rosemary leaves and cortex cinnamomi, crushing, and drying to obtain mixed particles; stirring and mixing the mixed particles and an ethanol water solution, standing, carrying out supercritical extraction treatment, collecting an oil phase product through a separator, and purifying to obtain a rosemary-cinnamon composite extract; the preparation method comprises the following steps: performing ultrasonic stirring treatment on a wheat germ extract, an ethanol water solution and a rosemary-cinnamon composite extract, adding phosphatidylserine and a chitosan solution, continuing stirring, performing primary baking, and then performing spray drying, thereby obtaining the finished product. The broiler chicken growth promoter prepared by the invention can obviously improve the intestinal health of broiler chickens and enhance the nutrient absorption, thereby promoting the improvement of the growth performance of the broiler chickens.

Description

Technical Field

[0001] This invention belongs to the technical field of feed additives, and relates to a broiler growth promoter based on plant extracts and its preparation method. Background Technology

[0002] In large-scale broiler farming, gut health is a core factor determining growth performance. As the main site of nutrient digestion and absorption, the gut's physical, chemical, immune, and microbial barriers work synergistically to directly affect nutrient utilization and the body's disease resistance. The physical barrier refers to the integrity of the intestinal mucosa; the chemical barrier involves mucus and antibacterial substances; the immune barrier includes immune cells and cytokines; and the microbial barrier depends on the balance of the gut microbiota.

[0003] However, broiler growth is easily affected by factors such as high-density farming environment, moldy feed, and pathogenic bacterial infection, leading to damage to the intestinal barrier: damage to the physical barrier will cause increased permeability of the intestinal mucosa, allowing harmful substances to enter the blood circulation; the decline in the function of the chemical and immune barriers will weaken the antibacterial and immune defense capabilities, induce intestinal flora imbalance, such as the overgrowth of Escherichia coli and Salmonella, which will lead to systemic inflammatory response and nutrient absorption disorders, ultimately manifested as stunted growth and increased mortality.

[0004] Traditional farming often relies on antibiotics to maintain gut health, but long-term use can easily lead to the proliferation of drug-resistant strains and drug residues, which is inconsistent with the trend of green farming. Plant extracts have become an alternative due to their natural antibacterial and antioxidant properties, but their use alone has limitations. Furthermore, when used directly, the active ingredients of plant extracts are easily destroyed by the high temperatures of feed processing and the acidic environment of broiler stomachs, resulting in low bioavailability and making it difficult to fully exert their synergistic regulatory effect on the intestinal barrier. Summary of the Invention

[0005] The purpose of this invention is to provide a broiler growth promoter based on plant extracts and its preparation method. This invention utilizes the synergistic effect of antioxidant rosemary essential oil, antibacterial cinnamon essential oil, and wheat germ extract, and uses chitosan and phosphatidylserine as carriers to improve the stability and absorption efficiency of the components. As a result, the growth promoter prepared by this invention can significantly improve the intestinal health of broilers, enhance nutrient absorption, and thus promote the improvement of broiler growth performance.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing a broiler growth promoter based on plant extracts, characterized in that the preparation method includes the following steps: S1. Mix and grind rosemary leaves and cinnamon bark, then dry to obtain mixed granules; S2. Mix the mixed particles and the ethanol-water solution, let stand, and then perform supercritical extraction. Collect the oil phase product through a separator and purify it to obtain the rosemary-cinnamon complex extract. S3. The wheat germ extract, ethanol aqueous solution and rosemary-cinnamon complex extract are ultrasonically stirred, phosphatidylserine and chitosan solution are added and stirred again, and after initial drying, they are spray dried to complete the preparation.

[0007] As a preferred technical solution of the present invention, in step S1, the pulverization is pulverizing to below 40 mesh, the drying is vacuum drying to a moisture content ≤8%, and the mass ratio of rosemary leaves and cinnamon bark is 3.0-3.8:2.0-2.5.

[0008] As a preferred technical solution of the present invention, the essential oil extracted from rosemary leaves is rich in rosmarinic acid, caryophyllophenol and other components. In the feed industry, it can delay the oxidation and deterioration of fat and vitamins in feed through strong antioxidant properties, thus extending the shelf life. At the same time, its antibacterial activity can inhibit harmful microorganisms such as Escherichia coli and Salmonella in feed and in the intestines of broilers, maintain the balance of intestinal flora, enhance the immunity of broilers, reduce intestinal diseases such as diarrhea, indirectly promote growth performance, and can partially replace antibiotics. It is suitable for broilers and other livestock and poultry.

[0009] As a preferred technical solution of the present invention, the essential oil extracted from cinnamon bark can inhibit intestinal pathogens (such as Clostridium perfringens) and reduce intestinal inflammation in feed through antibacterial and anti-inflammatory effects; at the same time, it can stimulate the secretion of digestive enzymes, improve the digestibility and absorption rate of feed nutrients, improve animal appetite and palatability, enhance the body's immunity, and reduce the incidence of diarrhea and other problems during breeding. It is widely used in the feed of pigs, chickens, aquatic animals and other animals, and has both growth-promoting and antibiotic-reducing effects.

[0010] As a preferred embodiment of the present invention, in step S2, the stirring and mixing is carried out at a speed of 300-500 rpm for 10-15 min, the settling time is 15-20 min, the supercritical extraction treatment is carried out at a pressure of 20 MPa, a temperature of 45-48℃, and a carbon dioxide flow rate of 22 L / h for 4-5 h, the purification is carried out by dehydration with anhydrous sodium sulfate and filtration through a 0.45 μm filter membrane, the parameters of the separator are 4.5 MPa pressure and 55℃ temperature, the mass ratio of the mixed particles to the ethanol aqueous solution is 1:3.0-3.5, and the concentration of the ethanol aqueous solution is 60 wt%.

[0011] As a preferred embodiment of the present invention, in step S3, the ultrasonic stirring treatment is performed by stirring at 500-800 rpm for 10-15 min, followed by ultrasonication at 250-300 W power for 20-30 min; the continued stirring is performed at room temperature for 15-20 min; the initial drying is performed by vacuum drying at 40-45℃ for 1.0-1.5 h; and the spray drying is performed at an atomization pressure of 0.3 MPa, an inlet air temperature of 175℃, an outlet air temperature of 78℃, and a feed rate of 8 mL / min. The mass ratio of the wheat germ extract, 60 wt% ethanol aqueous solution, rosemary-cinnamon complex extract, phosphatidylserine, and chitosan solution is 0.4-0.6: 2.5-3.0: 1.2-1.6: 0.15-0.21: 350-380; the concentration of the chitosan solution is 0.9 mg / mL, the solvent is 1 wt% aqueous acetic acid solution, and the molecular weight of chitosan in the chitosan solution is 150-300 kDa and the degree of deacetylation is 85-95%.

[0012] As a preferred technical solution of the present invention, the preparation method of wheat germ extract includes: taking wheat germ, defatting, and pulverizing; adding deionized water, adjusting pH, heating and stirring for extraction, then adding neutral protease, enzymatically hydrolyzing and inactivating the enzyme to obtain the extract; centrifuging the extract, taking the supernatant for filtration, separating by ultrafiltration membrane, concentrating the ultrafiltration filtrate under reduced pressure, and drying to obtain wheat germ extract.

[0013] As a preferred technical solution of the present invention, wheat germ extract is rich in free amino acids, vitamins and bioactive substances. In the feed field, it can balance feed nutrition by supplementing amino acids, improve protein utilization, and promote the growth, development and digestion of young broilers. Its antioxidant components can enhance the immunity and stress resistance of broilers, improve feed palatability, delay oxidative deterioration, and can also partially replace antibiotics and high-priced protein sources.

[0014] The beneficial effects of this invention are: This invention utilizes the synergistic effect of antioxidant rosemary essential oil, antibacterial cinnamon essential oil, and wheat germ extract, with chitosan and phosphatidylserine forming a carrier to enhance the stability and absorption efficiency of the components. This results in an additive that can significantly improve the intestinal health of broilers, enhance nutrient absorption, and thus promote the growth performance of broilers. Detailed Implementation

[0015] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0016] The preparation method of wheat germ extract includes: taking dried wheat germ, first removing impurities by sieving, defatting by pressing, controlling the moisture content of the defatted germ meal to 8%, and pulverizing it to below 80 mesh; adding deionized water at a material-to-liquid ratio of 1g:15mL, adjusting the pH to 6.0 with 1mol / L hydrochloric acid, and stirring and extracting in a 60℃ water bath for 1.5h; adding 0.3% by weight of neutral protease (enzyme activity of 50000U / g) of germ powder, enzymatically hydrolyzing for 1h, and then heating to 90℃ to inactivate the enzyme for 15min; centrifuging the extract at 3000r / min for 15min, taking the supernatant and filtering it through a 0.22μm microfiltration membrane to remove impurities, and then separating and purifying it through an ultrafiltration membrane with a molecular weight cutoff of 5000Da; concentrating the purified filtrate under reduced pressure at 60℃ and -0.085MPa to a solid content of 30%, and freeze-drying it to a water content of 2.13wt% to obtain a light yellow powdery wheat germ extract. Example

[0017] A method for preparing a broiler growth promoter based on plant extracts includes the following steps: S1. Mix rosemary leaves and cinnamon bark and pulverize them to a fineness below 40 mesh, then vacuum dry them to a moisture content of 6% to obtain mixed granules; the mass ratio of rosemary leaves to cinnamon bark is 3.0:2.0; S2. The mixed particles and ethanol-water solution were stirred at 300 rpm for 10 min, allowed to stand for 15 min, and then subjected to supercritical extraction at 20 MPa pressure, 45℃ temperature, and 22 L / h carbon dioxide flow rate for 4 h. The oil phase product was collected in a separator at 4.5 MPa pressure and 55℃ temperature, dehydrated with anhydrous sodium sulfate, and filtered through a 0.45 μm filter membrane to obtain a rosemary-cinnamon complex extract. The mass ratio of the mixed particles to the ethanol-water solution was 1:3.0, and the concentration of the ethanol-water solution was 95 wt%. S3. Wheat germ extract, 60wt% ethanol aqueous solution, and rosemary-cinnamon complex extract were stirred at 50℃ and 500rpm for 10min, then sonicated at 250W for 20min. Phosphatidylserine and chitosan solution were added and stirred for another 15min at room temperature. The mixture was then vacuum dried at 40℃ for 1.0h, followed by spray drying at 0.3MPa atomization pressure, 175℃ inlet air temperature, 78℃ outlet air temperature, and 8mL / min feed rate. The preparation was then complete. The mass ratio of wheat germ extract, 60wt% ethanol aqueous solution, rosemary-cinnamon complex extract, phosphatidylserine, and chitosan solution was 0.4:2.5:1.2:0.15:350. The concentration of the chitosan solution was 0.9mg / mL, the solvent was 1wt% acetic acid aqueous solution, and the molecular weight of chitosan in the chitosan solution was 150 kDa with a degree of deacetylation of 85%. Example

[0018] A method for preparing a broiler growth promoter based on plant extracts includes the following steps: S1. Mix rosemary leaves and cinnamon bark and pulverize them to a fineness below 40 mesh, then vacuum dry them to a moisture content of 7% to obtain mixed granules; the mass ratio of rosemary leaves to cinnamon bark is 3.4:2.2; S2. The mixed particles and ethanol-water solution were stirred at 400 rpm for 12 min, allowed to stand for 18 min, and then subjected to supercritical extraction at 20 MPa pressure, 46℃ temperature, and 22 L / h carbon dioxide flow rate for 4.5 h. The oil phase product was collected in a separator at 4.5 MPa pressure and 55℃ temperature, dehydrated with anhydrous sodium sulfate, and filtered through a 0.45 μm filter membrane to obtain the rosemary-cinnamon complex extract. The mass ratio of the mixed particles to the ethanol-water solution was 1:3.2, and the concentration of the ethanol-water solution was 95 wt%. S3. Wheat germ extract, 60wt% ethanol aqueous solution, and rosemary-cinnamon complex extract were stirred at 55℃ and 650rpm for 12min, then sonicated at 275W for 25min. Phosphatidylserine and chitosan solution were added and stirred for another 18min at room temperature. The mixture was then vacuum dried at 42℃ for 1.2h, followed by spray drying at 0.3MPa atomization pressure, 175℃ inlet air temperature, 78℃ outlet air temperature, and 8mL / min feed rate. The preparation was then complete. The mass ratio of wheat germ extract, 60wt% ethanol aqueous solution, rosemary-cinnamon complex extract, phosphatidylserine, and chitosan solution was 0.5:2.8:1.4:0.18:365. The concentration of the ethanol aqueous solution was 60wt%, the concentration of the chitosan solution was 0.9mg / mL, and the solvent was 1wt% acetic acid aqueous solution. The molecular weight of the chitosan in the chitosan solution was 220 kDa, and the degree of deacetylation was 90%. Example

[0019] A method for preparing a broiler growth promoter based on plant extracts includes the following steps: S1. Mix rosemary leaves and cinnamon bark and pulverize them to a fineness below 40 mesh, then vacuum dry them to a moisture content of 8% to obtain mixed granules; the mass ratio of rosemary leaves to cinnamon bark is 3.8:2.5; S2. The mixed particles and ethanol-water solution were stirred at 500 rpm for 15 min, allowed to stand for 20 min, and then subjected to supercritical extraction at 20 MPa pressure, 48℃ temperature, and 22 L / h carbon dioxide flow rate for 5 h. The oil phase product was collected in a separator at 4.5 MPa pressure and 55℃ temperature, dehydrated with anhydrous sodium sulfate, and filtered through a 0.45 μm filter membrane to obtain the rosemary-cinnamon complex extract. The mass ratio of the mixed particles to the ethanol-water solution was 1:3.5, and the concentration of the ethanol-water solution was 95 wt%. S3. Wheat germ extract, 60wt% ethanol aqueous solution, and rosemary-cinnamon complex extract were stirred at 60℃ and 800rpm for 15min, then sonicated at 300W for 30min. Phosphatidylserine and chitosan solution were added and stirred for another 20min at room temperature. The mixture was then vacuum dried at 45℃ for 1.5h, followed by spray drying at 0.3MPa atomization pressure, 175℃ inlet air temperature, 78℃ outlet air temperature, and 8mL / min feed rate. The preparation was then complete. The mass ratio of wheat germ extract, 60wt% ethanol aqueous solution, rosemary-cinnamon complex extract, phosphatidylserine, and chitosan solution was 0.6:3.0:1.6:0.21:380. The concentration of the ethanol aqueous solution was 60wt%, the concentration of the chitosan solution was 0.9mg / mL, the solvent was 1wt% acetic acid aqueous solution, and the molecular weight of the chitosan in the chitosan solution was 300 kDa with a degree of deacetylation of 95%.

[0020] Comparative Example 1 Compared with Example 3, Comparative Example 1 differs in that cinnamon bark is used instead of rosemary leaves, otherwise they are the same.

[0021] Comparative Example 2 Compared with Example 3, Comparative Example 2 differs in that rosemary leaves are used instead of cinnamon bark, otherwise they are the same.

[0022] Comparative Example 3 Compared with Example 3, Comparative Example 3 differs in that it uses rosemary-cinnamon complex extract instead of wheat germ extract, otherwise they are the same.

[0023] Comparative Example 4 Compared with Example 3, Comparative Example 4 differs in step S3; S3. Wheat germ extract, ethanol aqueous solution and rosemary-cinnamon complex extract were stirred at 60℃ and 800rpm for 45min. Phosphatidylserine and chitosan solution were added and stirred at room temperature for another 20min. The mixture was then vacuum dried at 45℃ for 1.5h and spray dried at 0.3MPa atomization pressure, 175℃ inlet air temperature, 78℃ outlet air temperature and 8mL / min feed rate to complete the preparation. Everything else is the same.

[0024] Comparative Example 5 Compared with Example 3, Comparative Example 5 differs in step S3; S3. Wheat germ extract, ethanol aqueous solution and rosemary-cinnamon complex extract were stirred at 60℃ and 800rpm for 15min, then sonicated at 300W for 30min. Phosphatidylserine and chitosan solution were added and stirred at room temperature for another 20min. Then, spray drying was carried out at 0.3MPa atomization pressure, 175℃ inlet air temperature, 78℃ outlet air temperature and 8mL / min feed rate to complete the preparation. All other steps were the same.

[0025] The accelerators prepared in Examples 1-3 and Comparative Examples 1-5 were tested for the following properties, and the test results are shown in Table 1.

[0026] Growth experiment: (a) Select healthy AA broilers of similar weight at 1 day old and randomly divide them into 9 groups of 8 birds each; each group is set up in parallel with 4 subgroups. They are fed with 0% growth promoter (control group), growth promoter of Examples 1-3 and Comparative Examples 1-5 respectively. The amount of growth promoter in each group is 0.5% of the total weight of the experimental diet. The experimental period is 42 days. The experimental diet consisted of a basal diet and a growth promoter. The basal diet, by weight, comprised the following components: 55.50 parts corn, 30.00 parts soybean meal, 5.50 parts rapeseed meal, 4.80 parts soybean oil, 0.35 parts L-lysine, 0.32 parts DL-methionine, 0.18 parts threonine, 1.60 parts limestone powder, 1.75 parts dicalcium phosphate, and 1.00 part compound premix. The compound premix provided per kilogram of diet: 8000 IU vitamin A, 1000 IU vitamin D3, 30 mg vitamin E, 2 mg vitamin K3, 1.5 mg vitamin B1, 6 mg vitamin B2, 2 mg vitamin B6, and 1 mg vitamin B6. 12 0.03mg, D-pantothenic acid 15mg, niacin 30mg, biotin 0.3mg, folic acid 1.2mg, and Cu 10mg, Fe 80mg, Mn 80mg, Zn 120mg, I 0.5mg, Se 0.25mg.

[0027] (ii) Record the initial weight of the broilers on day 1. At day 42, after fasting for 12 hours, weigh the AA broilers in each replicate. Feeding and management were carried out according to the "Cobb Broiler Feeding and Management Manual," and routine vaccinations against Marek's disease, Newcastle disease, infectious bronchitis, and infectious bursal disease were administered. Free access to feed and water was provided. Feed consumption for each replicate during the experiment was recorded, and the average daily weight gain and average daily feed intake for each group were calculated.

[0028] Table 1. Broiler Growth Data Group 42-day-old broiler chicken weight (g) Average daily feed intake (g / d) Average daily weight gain (g / d) control group 2550 125 59.76 Example 1 2820 128 66.19 Example 2 2890 129 67.86 Example 3 2950 130 69.29 Comparative Example 1 2680 126 62.86 Comparative Example 2 2700 127 63.33 Comparative Example 3 2750 128 64.52 Comparative Example 4 2650 126 62.14 Comparative Example 5 2630 125 61.67 As can be seen from the test results in Table 1, compared with Comparative Examples 1-5, the broiler growth performance of Examples 1-3 is significantly better than that of Comparative Examples 1-5 due to the synergistic effect of rosemary essential oil, cinnamon essential oil and wheat germ extract, combined with the process of ultrasonic promotion of reaction and drying to ensure carrier stability.

[0029] This invention utilizes rosemary essential oil, which contains active ingredients such as eucalyptol and rosmarinic acid, to inhibit oxidative stress in the broiler intestines and effectively protect the integrity of the intestinal mucosa. Cinnamon essential oil contains active ingredients such as cinnamaldehyde, which can inhibit the growth of harmful bacteria (such as Escherichia coli) in the intestines and reduce nutrient consumption and intestinal inflammation. Wheat germ extract is rich in amino acids (such as lysine and methionine) and vitamin E, which not only directly supplement the nutrients needed for broiler growth, but its amino acids can also undergo an addition reaction with cinnamaldehyde to form a stable Schiff base complex, which enhances the antibacterial effect and reduces irritation.

[0030] This invention utilizes a composite carrier formed by chitosan (a positively charged polysaccharide) and phosphatidylserine (an amphoteric lipid) to stably encapsulate the active ingredients of rosemary essential oil, cinnamon essential oil, and wheat germ extract through emulsification and encapsulation. Chitosan enhances the adhesion of the formulation in the intestine and slows down component degradation; phosphatidylserine promotes the passage of lipid-soluble components (such as essential oils) through intestinal epithelial cells, improving absorption efficiency. The synergy between these three components and the carrier strengthens the comprehensive effects of antioxidation, antibacterial activity, and nutritional supplementation, and improves bioavailability through structural optimization, ultimately resulting in increased feed intake and faster weight gain in broilers. In contrast, the comparative method, due to the absence of a certain component or process (such as single essential oil or lack of carrier protection), disrupted the above synergy, leading to a decrease in efficacy.

[0031] This invention utilizes the cavitation effect of ultrasonic treatment to accelerate the formation of more stable Schiff base derivatives between amino acids in cinnamon essential oil and wheat germ extract. These Schiff base derivatives can retain the intestinal antibacterial ability of cinnamaldehyde and improve the targeted absorption efficiency of cinnamaldehyde in the intestine of broilers through amino acid carriers, while avoiding the irritation of free cinnamaldehyde.

[0032] In this invention, when preparing chitosan-phosphatidylserine coatings by spray drying, if the drying step is omitted, ethanol residue will result in a decrease in the viscosity of the wall material, easy breakage of droplets during spraying, and a loose structure and uneven particle size of the coating, leading to a reduced encapsulation rate.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a broiler growth promoter based on plant extracts, characterized in that, The preparation method includes the following steps: S1. Mix and grind rosemary leaves and cinnamon bark, then dry to obtain mixed granules; S2. Mix the mixed particles and the ethanol-water solution, let stand, and then perform supercritical extraction. Collect the oil phase product through a separator and purify it to obtain the rosemary-cinnamon complex extract. S3. The wheat germ extract, ethanol aqueous solution and rosemary-cinnamon complex extract are ultrasonically stirred, phosphatidylserine and chitosan solution are added and stirred again, and after initial drying, they are spray dried to complete the preparation.

2. The method for preparing a broiler growth promoter based on plant extracts according to claim 1, characterized in that: In step S1, the pulverization is pulverizing to a mesh size of less than 40, and the drying is vacuum drying to a moisture content of ≤8%.

3. The method for preparing a broiler growth promoter based on plant extracts according to claim 1, characterized in that: In step S1, the mass ratio of rosemary leaves to cinnamon bark is 3.0-3.8:2.0-2.

5.

4. The method for preparing a broiler growth promoter based on plant extracts according to claim 1, characterized in that: In step S2, the stirring and mixing is performed at a speed of 300-500 rpm for 10-15 minutes, and the settling time is 15-20 minutes.

5. The method for preparing a broiler growth promoter based on plant extracts according to claim 1, characterized in that: In step S2, the supercritical extraction process is supercritical extraction at a pressure of 20 MPa, a temperature of 45-48°C, and a carbon dioxide flow rate of 22 L / h for 4-5 hours.

6. The method for preparing a broiler growth promoter based on plant extracts according to claim 1, characterized in that: In step S2, the parameters of the separator are 4.5 MPa pressure and 55°C temperature, and the mass ratio of the mixed particles to the ethanol aqueous solution is 1:3.0-3.

5.

7. The method for preparing a broiler growth promoter based on plant extracts according to claim 1, characterized in that: In step S3, the ultrasonic stirring treatment is to stir at a temperature of 50-60℃ and a speed of 500-800rpm for 10-15 minutes, followed by ultrasonication at a power of 250-300W for 20-30 minutes, and the continued stirring is to continue stirring at room temperature for 15-20 minutes.

8. The method for preparing a broiler growth promoter based on plant extracts according to claim 1, characterized in that: In step S3, the initial drying is vacuum drying at a temperature of 40-45℃ for 1.0-1.5h.

9. The method for preparing a broiler growth promoter based on plant extracts according to claim 1, characterized in that: In step S3, the mass ratio of the wheat germ extract, ethanol aqueous solution, rosemary-cinnamon complex extract, phosphatidylserine, and chitosan solution is 0.4-0.6: 2.5-3.0: 1.2-1.6: 0.15-0.21: 350-380; the concentration of the chitosan solution is 0.9 mg / mL, and the solvent is 1 wt% acetic acid aqueous solution.

10. A broiler growth promoter based on plant extracts prepared by the preparation method according to any one of claims 1 to 9.