Growth-promoting fermented feed additive and preparation method thereof

Abstract

The invention belongs to the technical field of feed additives, and particularly relates to a fermented feed additive for promoting growth and a preparation method thereof. The additive comprises the following components in parts by weight: 10-20 parts of microbial fermentation bacteria liquid, 1-5 parts of modified montmorillonite, 5-10 parts of a chlorella extract and 0.5-1 part of chicken bone powder, a preparation process of the modified montmorillonite comprises the following steps: (1) adding montmorillonite into a nitric acid solution, heating and stirring for a period of time, and filtering, washing and calcining to obtain pretreated montmorillonite; (2) adding sodium carbonate, ferric nitrate and calcium nitrate into water, heating and stirring to obtain a mixed solution; and (3) dispersing the montmorillonite pretreated in the step (1) in water, adding the mixed solution in the step (2), and carrying out heating reaction to obtain the modified montmorillonite. The additive disclosed by the invention not only can improve the activity of a fermentation strain and regulate the microecological balance of intestinal tracts, but also can meet various nutritional requirements in the animal growth process and promote the animal growth performance.

Description

Technical Field

[0001] The invention belongs to the technical field of feed additives, and in particular relates to a growth-promoting fermented feed additive and a preparation method thereof. Background Art

[0002] In modern animal husbandry, feed additives are an important means to improve animal production performance and health status, and are of great significance in promoting animal growth and health. With the advancement of science and technology and the increasing attention of consumers to food safety and quality, the development of efficient, environmentally friendly and safe feed additives has become a hot topic in current research. Among them, fermented feed additives have shown significant advantages in promoting animal intestinal health, improving feed conversion rate and reducing the use of antibiotics due to their unique microbial active ingredients and prebiotic effects, and have received widespread attention and application.

[0003] Fermented feed additives usually contain one or more probiotics, which produce beneficial metabolites such as organic acids, enzymes, vitamins, etc. through the fermentation process. These substances help improve the balance of animal intestinal microecology, increase feed digestibility and utilization, and promote healthy growth of animals. However, existing fermented feed additives still have room for improvement in maintaining the activity of fermented strains and promoting animal growth. Especially after long-term storage, how to ensure the high efficiency and stability of fermented strains while maximizing their effect in promoting animal growth is an important challenge currently faced.

[0004] Montmorillonite is a natural layered silicate mineral that is widely used in many fields due to its unique physical and chemical properties, such as high specific surface area, good adsorption performance, and cation exchange capacity. For example, in the agricultural field, montmorillonite is often used as a soil conditioner to promote crop growth by adjusting soil structure and improving soil water and fertilizer retention capacity. However, when directly applied to feed additives, its effect is relatively limited, mainly reflected in the adsorption of nutrients in feed, and lacks specific functional optimization for animal growth needs.

[0005] Therefore, there is an urgent need to provide a growth-promoting fermented feed additive to solve the above problems. Summary of the invention

[0006] In order to overcome the deficiencies of the prior art, the primary purpose of the present invention is to provide a growth-promoting fermented feed additive.

[0007] Another object of the present invention is to provide a method for preparing a growth-promoting fermented feed additive.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A growth-promoting fermented feed additive, comprising the following components in parts by weight: 10-20 parts of microbial fermentation liquid, 1-5 parts of modified montmorillonite, 5-10 parts of chlorella extract, and 0.5-1 part of chicken bone powder;

[0010] The preparation process of the modified montmorillonite is as follows:

[0011] (1) adding montmorillonite to a nitric acid solution, heating and stirring for a period of time, filtering, washing, and calcining to obtain pretreated montmorillonite;

[0012] (2) adding sodium carbonate, ferric nitrate and calcium nitrate into water, heating and stirring to obtain a mixed solution;

[0013] (3) Dispersing the montmorillonite pretreated in step (1) in water evenly, then adding the mixed solution in step (2), heating and reacting to obtain modified montmorillonite.

[0014] Furthermore, the preparation process of the microbial fermentation liquid is as follows: using Rhus chinensis leaf water extract residue, Pueraria lobata root water extract residue and cooked potatoes as fermentation medium, using Bacillus subtilis liquid and Saccharomyces cerevisiae liquid as fermentation seed liquid to inoculate into the fermentation medium for fermentation, so as to obtain the microbial fermentation liquid.

[0015] Furthermore, the concentration of the nitric acid solution in step (1) is 3-7 mol / L; the solid-liquid ratio of the montmorillonite to the nitric acid solution is 1 g:(9-11) mL; the heating and stirring temperature is 70-80° C., and the time is 5-6 h.

[0016] Furthermore, the calcination temperature in step (1) is 500-600° C. and the calcination time is 2-3 hours.

[0017] Furthermore, the mass ratio of the sodium carbonate, ferric nitrate, calcium nitrate and water in step (2) is (15-30):(35-55):(5-15):(800-1100).

[0018] Furthermore, the heating and stirring in step (2) is performed at a temperature of 40-50° C. and for a time of 10-14 h.

[0019] Furthermore, the solid-liquid ratio of the pretreated montmorillonite and water in step (3) is 1:(8-10); the mass ratio of the pretreated montmorillonite to the sodium carbonate in the mixed solution of step (2) is 1:(0.5-1); the temperature of the heating reaction is 70-90°C and the time is 5-7h.

[0020] Furthermore, the mass ratio of the water extract of Rhus chinensis leaves, the water extract of Pueraria lobata and the cooked potatoes is 1:(2-5):(1-2).

[0021] Furthermore, the inoculation amount of the fermentation seed liquid is 1-5%; the concentrations of the Bacillus subtilis liquid and the Saccharomyces cerevisiae liquid are both 2×10 9 -5×10 9 CFU / mL; the fermentation temperature is 32-37°C and the fermentation time is 32-48h.

[0022] Another object of the present invention is achieved by the following technical solutions:

[0023] The preparation method of the above-mentioned growth-promoting fermented feed additive comprises the following steps:

[0024] The microbial fermentation liquid, modified montmorillonite, chlorella extract and chicken bone meal are weighed according to the above weight proportions and mixed evenly to obtain the growth-promoting fermented feed additive.

[0025] The present invention has the following effects compared with the prior art:

[0026] 1. The growth-promoting fermented feed additive provided by the present invention is added with modified montmorillonite, which is obtained by subjecting the montmorillonite to acid treatment to increase the void structure, increase the specific surface area, and improve its adsorption capacity, and then adsorbing iron ions and calcium ions on the acid-treated montmorillonite, and performing pillar modification on its internal structure. The modified montmorillonite can not only provide trace elements for the growth of animals, but also adsorb toxins of harmful bacteria in the intestinal tract of animals, improve the intestinal microenvironment, and help to increase the growth rate and weight of animals. On the other hand, the modified montmorillonite utilizes its porous structure to adsorb Bacillus subtilis and Saccharomyces cerevisiae in the fermented bacterial liquid, which can significantly improve the stability of the fermented strains in the feed additive, thereby improving the utilization rate of the bacteria.

[0027] 2. The culture medium of the microbial fermentation liquid of the present invention is added with water extracts of Rhus chinensis leaves and Pueraria lobata roots, which work synergistically in a specific ratio to improve the growth of the bacteria, thereby exerting the probiotic effect of the strain and promoting animal growth. DETAILED DESCRIPTION

[0028] The present invention will be described in further detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. The test methods for which specific experimental conditions are not specified in the following examples are usually carried out according to conventional experimental conditions or according to the experimental conditions recommended by the manufacturer. Unless otherwise specified, the reagents and raw materials used in the present invention can be obtained commercially.

[0029] The Bacillus subtilis in the present invention is an existing strain with a preservation number of CICC10071, which is commercially available; the Saccharomyces cerevisiae is an existing strain with a preservation number of CICC 30196, which is commercially available.

[0030] The preparation method of the water extract residue of Rhus chinensis leaves in the following embodiment is as follows: the Rhus chinensis leaves are dried, sterilized at 120° C. for 10 min, then crushed, and screened through a 30-mesh sieve. Then, water equivalent to 15 times the weight of the Rhus chinensis leaves is added, and two reflux extractions are performed, each extraction time is 2 hours. After the extraction is completed, the extract is filtered out, and the remaining residue phase is the desired Rhus chinensis leaves water extract residue.

[0031] The pueraria root water extract residue is also prepared by adopting the above scheme.

[0032] The preparation method of the chlorella extract is as follows: chlorella powder, cellulase and pectinase are added to water, wherein the mass ratio of chlorella powder, cellulase, pectinase and water is 1:0.05:0.02:7. Enzymatic hydrolysis is performed at 48°C for 10 hours to obtain an enzymatic hydrolyzate, the enzymatic hydrolyzate is filtered through an ultrafiltration membrane, the retentate is collected, and the retentate is eluted with ethanol and deionized water and dried to obtain the chlorella extract.

[0033] Example 1

[0034] A growth-promoting fermented feed additive, comprising the following components in parts by weight: 15 parts of microbial fermentation liquid, 3 parts of modified montmorillonite, 7.5 parts of chlorella extract, and 0.75 parts of chicken bone powder;

[0035] The preparation process of the modified montmorillonite is as follows:

[0036] (1) adding montmorillonite to a 3 mol / L nitric acid solution, wherein the solid-liquid ratio of the montmorillonite to the nitric acid solution is 1 g:10 mL; heating to 75° C., stirring for reaction for 5.5 h, then filtering and collecting the solid, washing and drying it, and calcining it at 550° C. for 2.5 h to obtain a pretreated montmorillonite;

[0037] (2) weighing sodium carbonate, ferric nitrate, calcium nitrate and water in a mass ratio of 25:45:10:1000, then adding sodium carbonate, ferric nitrate and calcium nitrate into water, heating and stirring at 45° C. for 12 h to obtain a mixed solution;

[0038] (3) dispersing the pretreated montmorillonite in step (1) in water, and then adding the mixed solution of step (2) thereto, wherein the solid-liquid ratio of the pretreated montmorillonite to water is 1:9, and the mass ratio of the pretreated montmorillonite to the sodium carbonate in the mixed solution of step (2) is 1:0.75; heating the reaction at 80° C. for 6 h. After the reaction is completed, the reaction solution is allowed to stand at room temperature for 24 h, and then filtered, washed, and dried to obtain modified montmorillonite.

[0039] The preparation process of the microbial fermentation broth is as follows:

[0040] The water extract of Rhus chinensis leaves, the water extract of Pueraria root and cooked potatoes were mixed in a mass ratio of 1:4:1.5, and then sterile water was added in a solid-liquid ratio of 4:1 to obtain a fermentation medium; the Bacillus subtilis liquid (3.0×10 9 CFU / mL), Saccharomyces cerevisiae culture liquid (3.0×10 9 The seed fermentation liquid was inoculated into the fermentation medium at an inoculation rate of 3%, and fermented at 35°C for 40h to obtain the microbial fermentation liquid.

[0041] This embodiment also provides a method for preparing the above-mentioned growth-promoting fermented feed additive, comprising the following steps:

[0042] The microbial fermentation liquid, modified montmorillonite, chlorella extract and chicken bone meal are weighed according to the above weight proportions and mixed evenly to obtain the growth-promoting fermented feed additive.

[0043] Example 2

[0044] A growth-promoting fermented feed additive, comprising the following components in parts by weight: 10 parts of microbial fermentation liquid, 1 part of modified montmorillonite, 5 parts of chlorella extract, and 0.5 parts of chicken bone powder;

[0045] The preparation process of the modified montmorillonite is as follows:

[0046] (1) adding montmorillonite to a 5 mol / L nitric acid solution, wherein the solid-liquid ratio of the montmorillonite to the nitric acid solution is 1 g:10 mL; heating to 70° C., stirring for reaction for 5 h, then filtering and collecting the solid, washing and drying it, and calcining it at 500° C. for 2 h to obtain a pretreated montmorillonite;

[0047] (2) weighing sodium carbonate, ferric nitrate, calcium nitrate and water in a mass ratio of 15:35:5:800, then adding sodium carbonate, ferric nitrate and calcium nitrate into water, heating and stirring at 40° C. for 10 h to obtain a mixed solution;

[0048] (3) dispersing the pretreated montmorillonite in step (1) in water, and then adding the mixed solution of step (2) thereto, wherein the solid-liquid ratio of the pretreated montmorillonite to water is 1:8, and the mass ratio of the pretreated montmorillonite to the sodium carbonate in the mixed solution of step (2) is 1:0.5; heating the reaction at 70° C. for 7 h. After the reaction is completed, the reaction solution is allowed to stand at room temperature for 24 h, and then filtered, washed, and dried to obtain modified montmorillonite.

[0049] The preparation process of the microbial fermentation broth is as follows:

[0050] The water extract of Rhus chinensis leaves, the water extract of Pueraria root and cooked potatoes were mixed in a mass ratio of 1:2:1, and then sterile water was added in a solid-liquid ratio of 4:1 to obtain a fermentation medium; the Bacillus subtilis liquid (2.0×10 9 CFU / mL), Saccharomyces cerevisiae culture liquid (2.0×10 9 CFU / mL) were mixed as fermentation seed liquid, inoculated into fermentation medium at an inoculation rate of 5%, and fermented at 32°C for 48h to obtain microbial fermentation liquid.

[0051] This embodiment also provides a method for preparing the above-mentioned growth-promoting fermented feed additive, comprising the following steps:

[0052] The microbial fermentation liquid, modified montmorillonite, chlorella extract and chicken bone meal are weighed according to the above weight proportions and mixed evenly to obtain the growth-promoting fermented feed additive.

[0053] Example 3

[0054] A growth-promoting fermented feed additive, comprising the following ingredients in parts by weight: 20 parts of microbial fermentation liquid, 5 parts of modified montmorillonite, 10 parts of chlorella extract, and 1 part of chicken bone powder;

[0055] The preparation process of the modified montmorillonite is as follows:

[0056] (1) adding 7 mol / L nitric acid solution to montmorillonite, heating to 80°C, stirring and reacting for 6 hours, then filtering and collecting the solid, washing and drying it, and calcining it at 600°C for 2 hours to obtain pretreated montmorillonite;

[0057] (2) weighing sodium carbonate, ferric nitrate, calcium nitrate and water in a mass ratio of 30:55:15:1100, then adding sodium carbonate, ferric nitrate and calcium nitrate into water, heating and stirring at 50° C. for 10 h to obtain a mixed solution;

[0058] (3) dispersing the pretreated montmorillonite in step (1) in water, and then adding the mixed solution of step (2) thereto, wherein the solid-liquid ratio of the pretreated montmorillonite to water is 1:10, and the mass ratio of the pretreated montmorillonite to the sodium carbonate in the mixed solution of step (2) is 1:1; heating the reaction at 90° C. for 5 h. After the reaction is completed, the reaction solution is allowed to stand at room temperature for 24 h, and then filtered, washed, and dried to obtain modified montmorillonite.

[0059] The preparation process of the microbial fermentation broth is as follows:

[0060] The water extract of Rhus chinensis leaves, the water extract of Pueraria root and cooked potatoes were mixed evenly in a mass ratio of 1:5:2, and then sterile water was added in a solid-liquid ratio of 4:1 to obtain a fermentation medium; the Bacillus subtilis liquid (5.0×10 9 CFU / mL), Saccharomyces cerevisiae culture liquid (5.0×10 9 The mixture was mixed with 1% CFU / mL of water as fermentation seed solution, inoculated into the fermentation medium at an inoculation rate of 1%, and fermented at 37°C for 32h to obtain the microbial fermentation solution.

[0061] This embodiment provides a method for preparing a growth-promoting fermented feed additive, comprising the following steps:

[0062] The microbial fermentation liquid, modified montmorillonite, chlorella extract and chicken bone meal are weighed according to the above weight proportions and mixed evenly to obtain the growth-promoting fermented feed additive.

[0063] Comparative Example 1

[0064] The difference between Comparative Example 1 and Example 1 is that the modified montmorillonite is replaced by montmorillonite, and the rest is consistent with Example 1.

[0065] Comparative Example 2

[0066] The difference between this comparative example 2 and example 1 is that when preparing the microbial fermentation liquid, the water extract of Pueraria root is omitted from the fermentation medium, and the dosage ratio of the water extract of Rhus chinensis leaves to the cooked potatoes is adjusted to 5:1; the rest is consistent with example 1.

[0067] Comparative Example 3

[0068] The difference between this comparative example 3 and Example 1 is that when preparing the microbial fermentation liquid, the water extract residue of Rhus chinensis leaves is omitted from the fermentation medium, and the dosage ratio of the water extract residue of Pueraria lobata to the cooked potatoes is adjusted to 5:1; the rest is consistent with Example 1.

[0069] Comparative Example 4

[0070] The difference between this comparative example 4 and Example 1 is that when preparing the microbial fermentation bacterial liquid, the mass ratio of the water extract residue of Rhus chinensis leaves, the water extract residue of Pueraria root and the cooked potatoes is adjusted to 2:1:1, and the rest is consistent with Example 1.

[0071] Test Example 1

[0072] In order to verify the activity of bacteria in the fermented feed additives prepared in Examples 1-3 and Comparative Examples 1-4 of the present invention, the following method was used to investigate: the fermented feed additives prepared in the above groups were stored at room temperature for three months, added to 0.9% physiological saline, and filtered to obtain a test solution; a feed additive without adding microbial fermentation solution was set as a blank control group, and an ELISA instrument was used to detect the absorbance value of each group of test solutions at a wavelength of 600nm. The specific results are recorded in Table 1.

[0073] Table 1 Results of the activity of bacteria in each group of fermented feed additives

[0074] Group Before storage Three months later Example 1 Group 1.52 1.38 Example 2 Group 1.45 1.29 Example 3 Group 1.49 1.34 Comparative Example 1 1.48 0.96 Comparative Example 2 1.17 1.02 Comparative Example 3 1.22 1.09 Comparative Example 4 1.39 1.25 Blank control group 0.56 0.57

[0075] From the experimental results in Table 1, it can be seen that the absorbance values ​​of Example 1-3 groups are significantly higher than those of Comparative Example 1-4 groups, indicating that the strains in the fermented feed additives of Example 1-3 groups have higher activity and better growth. Moreover, after three months of storage, the absorbance value of the strain did not decrease significantly, and the absorbance value of the strain was still 91% of the value before storage.

[0076] Comparative Example 1 group replaced modified montmorillonite with montmorillonite. Compared with Example 1 group, its absorbance value was significantly reduced after storage for three months, that is, the activity of bacteria in fermented feed additives decreased. It can be seen that modified montmorillonite can improve the stability and activity of bacteria in feed additives. Compared with Example 1, Comparative Example 2-3 groups adjusted the types and dosages of Pueraria lobata water extract residues and Rhus chinensis leaf water extract residues in the fermentation medium, and the absorbance value was significantly reduced, which shows that Rhus chinensis leaf water extract residues and Pueraria lobata water extract residues can work synergistically to promote the growth of bacteria and enhance the strain activity of Bacillus subtilis and Saccharomyces cerevisiae strains. Comparative Example 4 group adjusted the ratio of Rhus chinensis leaf water extract residues and Pueraria lobata water extract residues in the fermentation medium, and the absorbance value was also reduced, indicating that when a specific ratio of Rhus chinensis leaf water extract residues and Pueraria lobata water extract residues were added to the fermentation medium, the growth of Bacillus subtilis and Saccharomyces cerevisiae strains was better and the strain activity was better.

[0077] Test Example 2

[0078] (1) A total of 56 healthy fattening pigs weighing about 80 kg were selected from a local breeding farm and randomly divided into 8 groups, each with 7 pigs. The feed additives of the corresponding groups were added to the corn-soybean meal type basal diet of the Example 1-3 and the Comparative Example 1-4 groups, respectively (the amount of the additive was 0.8% of the amount of the corn-soybean meal type basal diet), and the feed additive of the present invention was not added to the corn-soybean meal type basal diet of the control group; during the feeding period, each fattening pig was allowed to drink water freely, and the daily feed intake and the changes in the weight of the fattening pigs after feeding for 30 days were recorded, and the average feed-to-weight ratio was calculated. The relevant test results are shown in Table 2.

[0079] (2) After 30 days of feeding, a fattening pig with a medium weight was selected from each replicate for slaughter. The live weight, carcass weight, and slaughter rate of the fattening pigs in Example 1 to 3 and Comparative Example 1 to 4 were measured, where slaughter rate (%) = (carcass weight / live weight before slaughter) × 100%. The specific test results are recorded in Table 3.

[0080] Table 2 Effects of feed additives on growth performance of finishing pigs

[0081]

[0082] It can be seen from the experimental results in Table 2 that the average daily weight gain and feed intake of the fattening pigs in Example 1-3 groups are higher than those in Comparative Example 1-4 groups.

[0083] Compared with the Example 1 group, the feed additive of the Comparative Example 1 group contains unmodified montmorillonite, and the daily weight gain and feed intake of the fattening pigs in the Comparative Example 1 group are not as good as those in the Example 1. It can be seen that the modified montmorillonite plays an important role in improving the daily weight gain and daily feed intake of animals. On the one hand, the iron ions and calcium ions adsorbed in the pores of the modified montmorillonite of the present invention can provide necessary trace elements for animal growth, and the modified montmorillonite also has the function of adsorbing harmful bacteria and toxins in the intestinal tract of animals and adjusting the intestinal tract of fattening pigs, which helps to improve the growth rate and weight of animals. On the other hand, the modified montmorillonite uses its pore structure to adsorb Bacillus subtilis and Saccharomyces cerevisiae in the fermentation liquid, which can improve the stability and activity of the fermentation strains in the feed additive, thereby improving the utilization rate of the bacteria, giving full play to the beneficial effects of the bacteria, and promoting animal growth.

[0084] Compared with Example 1, the preparation method of the fermentation liquid was adjusted in Comparative Examples 2-4, and the daily weight gain and feed intake of fattening pigs also decreased to varying degrees. Combined with the results of bacterial activity in Experimental Example 1, it can be seen that the water extract of Rhus chinensis leaves and the water extract of Pueraria lobata in the fermentation medium act synergistically at a specific ratio to enhance the activity of Bacillus subtilis and Saccharomyces cerevisiae, thereby adjusting the intestinal health of animals and promoting the growth of fattening pigs.

[0085] Table 3 Pre-slaughter live weight, carcass weight and slaughter rate of fattening pigs in each group

[0086]

[0087]

[0088] From the experimental results in Table 3, it can be seen that the slaughter rate of animals in Example 1-3 groups is significantly higher than that in Comparative Example 1-4 groups.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. On the basis of the present invention, some modifications or replacements may be made thereto, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of protection claimed by the present invention.

Claims

1. A growth-promoting fermented feed additive, characterized in that: The invention comprises the following ingredients in parts by weight: 10-20 parts of microbial fermentation liquid, 1-5 parts of modified montmorillonite, 5-10 parts of chlorella extract, and 0.5-1 part of chicken bone powder; The preparation process of the modified montmorillonite is as follows: (1) adding montmorillonite to a nitric acid solution, heating and stirring, filtering, washing, and calcining to obtain pretreated montmorillonite; (2) adding sodium carbonate, ferric nitrate and calcium nitrate into water, heating and stirring to obtain a mixed solution; (3) dispersing the montmorillonite pretreated in step (1) in water, then adding the mixed solution in step (2), heating and reacting to obtain modified montmorillonite.

2. A growth-promoting fermented feed additive according to claim 1, characterized in that: The preparation process of the microbial fermentation liquid is as follows: using water extract residue of Rhus chinensis leaves, water extract residue of Pueraria lobata and cooked potatoes as fermentation medium, using Bacillus subtilis liquid and Saccharomyces cerevisiae liquid as fermentation seed liquid to inoculate into the fermentation medium for fermentation, so as to obtain the microbial fermentation liquid.

3. A growth-promoting fermented feed additive according to claim 1, characterized in that: The concentration of the nitric acid solution in step (1) is 3-7 mol / L; the solid-liquid ratio of the montmorillonite to the nitric acid solution is 1 g:(9-11) mL; the heating and stirring temperature is 70-80° C., and the time is 5-6 h.

4. A growth-promoting fermented feed additive according to claim 1, characterized in that: The calcination temperature in step (1) is 500-600° C. and the calcination time is 2-3 hours.

5. The growth-promoting fermented feed additive according to claim 1, characterized in that: The mass ratio of sodium carbonate, ferric nitrate, calcium nitrate and water in step (2) is (15-30):(35-55):(5-15):(800-1100).

6. The growth-promoting fermented feed additive according to claim 1, characterized in that: The heating and stirring in step (2) is performed at a temperature of 40-50° C. and for a time of 10-14 hours.

7. The growth-promoting fermented feed additive according to claim 1, characterized in that: The solid-liquid ratio of the pretreated montmorillonite and water in step (3) is 1:(8-10); the mass ratio of the pretreated montmorillonite to the sodium carbonate in the mixed solution of step (2) is 1:(0.5-1); the temperature of the heating reaction is 70-90°C and the time is 5-7h.

8. The growth-promoting fermented feed additive according to claim 2, characterized in that: The mass ratio of the water extract residue of Rhus chinensis leaves, the water extract residue of Pueraria lobata and the cooked potatoes is 1:(2-5):(1-2).

9. The growth-promoting fermented feed additive according to claim 2, characterized in that: The inoculation amount of the fermentation seed liquid is 1-5%; the concentrations of the Bacillus subtilis liquid and the Saccharomyces cerevisiae liquid are both 2×10 9 -5×10 9 CFU / mL; the fermentation temperature is 32-37°C and the fermentation time is 32-48h.

10. The method for preparing the growth-promoting fermented feed additive according to claim 1, characterized in that: The method comprises the following steps: weighing microbial fermentation liquid, modified montmorillonite, chlorella extract and chicken bone meal according to the weight proportions according to claim 1 and mixing them evenly to obtain the growth-promoting fermented feed additive.

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