Preparation method of fermented bamboo powder and application thereof in feed

Abstract

This invention discloses a method for preparing fermented bamboo powder and its application in animal feed, belonging to the field of animal feed technology. The method for preparing fermented bamboo powder includes the following steps: blasting bamboo raw materials to obtain steam-blasted bamboo powder; mixing the steam-blasted bamboo powder with nutritional supplements to obtain the fermentation substrate; compounding a bacterial solution of Bacillus subtilis, Aspergillus niger, Lactobacillus plantarum, and Saccharomyces cerevisiae to obtain a compound bacterial agent; adding the compound bacterial agent and immobilized cellulase to the fermentation substrate for solid-state fermentation; after fermentation, drying, pulverizing, and sieving the fermentation product to obtain fermented bamboo powder. The wet fermented bamboo powder prepared by this invention, when added to beef cattle feed, can increase the average daily weight gain of beef cattle, reduce the feed conversion ratio, and improve the digestibility and utilization rate of crude fiber. The dry fermented bamboo powder prepared by this invention, when added to sow feed, can increase the moisture content of sow feces and reduce constipation.

Description

Technical Field

[0001] This invention relates to the field of animal feed technology, and in particular to a method for preparing fermented bamboo powder and its application in feed. Background Technology

[0002] China boasts the world's richest bamboo resources. Bamboo, characterized by its rapid growth and high yield, is a renewable biomass resource with enormous development potential. Bamboo is rich in cellulose, hemicellulose, and lignin, with total dietary fiber accounting for over 75%. It also possesses advantages such as low mycotoxin content and abundant natural antioxidants, making it a promising candidate for developing functional fiber feed ingredients.

[0003] However, bamboo fiber mainly exists in the form of lignocellulose, which has a dense structure and hard texture, making it difficult for endogenous enzymes in the animal's gastrointestinal tract to directly decompose and utilize it. Traditional bamboo powder feed has low digestibility, which limits its large-scale direct application in the feed industry. In existing technologies, although there are technical solutions to optimize some properties of bamboo powder by physical crushing and high-temperature carbonization, these solutions are essentially physical modifications, which have limited impact on the bamboo fiber structure and suffer from high energy consumption.

[0004] Microbial fermentation technology is widely recognized as an effective means to enhance the nutritional value of crude fiber feeds, while also improving their physicochemical properties and flavor. However, existing research largely focuses on the application of single strains or simple mixed microbial communities. For fermented bamboo powder, how to achieve synergistic effects in fiber degradation, nutrient enhancement, and functional property improvement through efficient co-fermentation of microorganisms and enzymes remains a lack of systematic research. Furthermore, the pH of the system drops to 3.6-4.0 in the later stages of solid-state fermentation. Under this acidic environment, the activity of exogenously added cellulase decreases significantly. Maintaining the effective activity of exogenous enzymes in an acidic fermentation environment is a key technical problem that urgently needs to be solved in the practical application of microbial-enzyme co-fermentation technology. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies, such as the hard texture of bamboo powder raw materials, the difficulty in effectively destroying the fiber structure, and the low digestibility, and to provide a method for preparing fermented bamboo powder.

[0006] The purpose of this invention is to provide a safe and highly digestible fermented bamboo powder obtained by the preparation method described above.

[0007] Another object of the present invention is to provide the application of the fermented bamboo powder in animal husbandry, particularly in improving the growth performance of beef cattle and the intestinal health of sows.

[0008] To achieve the above objectives, the present invention provides the following solution: This invention provides a method for preparing fermented bamboo powder, comprising the following steps: Step 1: Preparation of fermentation substrate: Mix the steam-exploded bamboo powder with the nutrient additives evenly to obtain the fermentation substrate; Step 2: Preparation of adsorbed and immobilized cellulase: Citrate buffer and cellulase solution are sprayed sequentially onto the steam-blasted bamboo powder. The volume ratio of the cellulase solution to the mass ratio of the steam-blasted bamboo powder is 0.5-1 mL:1 g. After spraying the cellulase solution, the mixture is stirred, allowed to stand, and dried sequentially to obtain the adsorbed and immobilized cellulase. The enzyme activity of the adsorbed and immobilized cellulase is ≥10,000 U / g. Step 3: Preparation and solid-state fermentation of compound microbial agent: Bacillus subtilis ( Bacillus subtilis Aspergillus niger ( ) Aspergillus niger Lactobacillus plantarum ( Lactobacillus plantarum ) and brewer's yeast ( Saccharomyces cerevisiae The bacterial solutions were mixed evenly in a volume ratio of 1:1:1:1 to obtain the compound bacterial agent, wherein the total number of effective viable bacteria in the compound bacterial agent is not less than 10. 8 CFU / mL; The compound bacterial agent and the adsorbed and immobilized cellulase were added to the fermentation substrate to carry out solid-state fermentation to obtain the fermentation product; Step 4: Encapsulate the fermentation product to obtain wet fermented bamboo powder; and / or, dry, pulverize and sieve the fermentation product to obtain dry fermented bamboo powder.

[0009] Optionally, the method for preparing the steam-exploded bamboo powder includes: blasting bamboo raw materials to obtain steam-exploded bamboo powder; optionally, the bamboo raw material is 2-6 year old moso bamboo (…). Phyllostachys edulis Fresh bamboo stalks are used, and the fresh bamboo stalks are broken into bamboo blocks with a length of 3-5 cm. Optionally, fresh bamboo stalks of 2-6 year old moso bamboo are selected as raw materials. First, the branches, leaves and root nodes are removed, and then the bamboo blocks are broken by a mechanical crusher. After that, a baking soda solution is sprayed on the surface of the bamboo blocks. The mass of baking soda is 0.5% of the weight of the bamboo blocks, and the blocks are put into a steam explosion device for explosion treatment.

[0010] Optionally, the blasting treatment pressure is 1.0-2.5 MPa, more preferably 1.5 MPa, and the time is 240-480s, more preferably 360s; the blasted material is dried at 65℃ to a moisture content of 35%-40%, and then pulverized through a 20-mesh sieve to obtain the steam-blasted bamboo powder; after this pretreatment, the reducing sugar content of the bamboo powder increases from 0.5%-1% before treatment to 8-10%.

[0011] The method for preparing the fermentation substrate of the present invention includes: mixing the steam-exploded bamboo powder with nutritional supplements evenly to obtain the fermentation substrate; optionally, the weight percentage of each raw material in the fermentation substrate, based on dry matter, is: 90%-95% steam-exploded bamboo powder, 0-5% soybean meal, 0-5% cottonseed meal, 0-1% urea, and 0-5% molasses; more preferably, the weight percentage of each raw material, based on dry matter, is: 92.5% steam-exploded bamboo powder, 5% soybean meal, 2% molasses, and 0.5% urea.

[0012] Optionally, the molasses has a sugar content of ≥40%, and the urea is feed grade; soybean meal, cottonseed meal, urea and molasses are nutritional supplements, and the amount of nutritional supplements added must meet the following requirements: the crude protein content of the fermentation substrate, calculated on an air-dried basis, is not less than 3.5%, and the carbon-nitrogen ratio is not higher than 80:1.

[0013] Optionally, the preparation of the adsorbed and immobilized cellulase involves: drying the steam-blasted bamboo powder to a moisture content of 15%-20%, ultra-fine pulverizing it to 300-400 mesh, and then sequentially spraying it with citrate buffer and cellulase solution, wherein the concentration of the cellulase solution is 10,000-20,000 U / mL; the volume ratio of the cellulase solution to the mass ratio of the steam-blasted bamboo powder is 0.5-1 mL:1 g; after spraying the cellulase solution, stirring, standing, and drying to a moisture content of 10%-12% are performed to obtain the adsorbed and immobilized cellulase; optionally, ultra-fine pulverization to 300-400 mesh is performed using an impact mill; optionally, the bamboo powder is sprayed with pH 4.8 citrate buffer to swell it; and the cellulase is dissolved in pH 4.8 citrate buffer to prepare a cellulase solution.

[0014] Optionally, the stirring speed is 100-200 rpm for 30 minutes to allow the enzyme to fully penetrate the bamboo fiber micropores; the settling temperature is 25-30℃ for 2-4 hours; the drying method includes oven drying at 45-50℃ to a moisture content of 10%-12%, where the bamboo fiber micropores immobilize the enzyme protein through physical adsorption and microenvironment confinement. Cellulase can degrade cellulose and release soluble nutrients. This invention does not require a specific source for the cellulase, but requires that the cellulase exhibit cellulase activity under conditions of pH 3.0-6.0 and temperature 30-50℃.

[0015] This invention involves adding the compound microbial agent and the adsorbed and immobilized cellulase to the fermentation substrate for solid-state fermentation to obtain the fermentation product. Optionally, after adding the compound microbial agent and the adsorbed and immobilized cellulase, purified water is added to the fermentation substrate to adjust the moisture content to 40%-45%, and after mixing evenly, the substrate is placed in a fermentation tank and sealed for solid-state fermentation. Optionally, the inoculum amount of the compound microbial agent is 5%-8% of the dry weight of steam-exploded bamboo powder, and the amount of adsorbed and immobilized cellulase added is 10-50 U of enzyme activity units per gram of dry weight of steam-exploded bamboo powder, more preferably 25 U of enzyme activity units. The thickness of the solid-state fermentation substrate is 1.2-1.5 m, and the substrate is turned over after the fermentation temperature exceeds 45°C. The fermentation environment temperature is 28-32°C, and the fermentation time is 72-96 h. After 48 h of fermentation, the pH drops to 4.4-4.8, and after 72 h of fermentation, the pH drops to 3.6-4.0. The “10-50 U / g” mentioned in this invention refers to the enzyme activity units (U) of the adsorbed and immobilized cellulase added per gram of dry weight of fermentation substrate, rather than the mass of the adsorbed and immobilized enzyme powder.

[0016] Step 4: Post-processing: After the fermentation is completed, the fermentation product is packaged to obtain wet fermented bamboo powder; and / or, after the fermentation is completed, the fermentation product is dried, pulverized and sieved to obtain dry fermented bamboo powder.

[0017] Optionally, after fermentation, the fermentation product is dried at a low temperature of 60-70℃ until the moisture content is ≤14%, then crushed by a hammer mill and sieved (60-80 mesh) to obtain the dry fermented bamboo powder product.

[0018] This invention provides a fermented bamboo powder. The fermented bamboo powder prepared by this invention has a crude protein content of over 6% based on air-dried matter, has a bamboo acid aroma, a total dietary fiber content of over 70%, and a soft texture without any needle-like feel.

[0019] This invention provides an application of fermented bamboo powder in the preparation of ruminant feed, wherein 10%-30% by weight of the aforementioned wet fermented bamboo powder is added to the basal diet of ruminants; the wet fermented bamboo powder replaces straw or fermented straw-like roughage. The ruminants include cattle, more preferably beef cattle; the feed with added wet fermented bamboo powder can increase the average daily weight gain of beef cattle, reduce the feed conversion ratio, and improve the digestibility and utilization rate of crude fiber.

[0020] This invention provides an application of fermented bamboo powder in the preparation of feed for monogastric animals. The dry fermented bamboo powder is added at a weight ratio of 2.5%-5.0% to the basal diet of monogastric animals. The monogastric animals include pigs, more preferably sows. The dry fermented bamboo powder can replace fiber raw materials such as wheat bran and rice bran meal. Feed with added dry fermented bamboo powder can increase the moisture content of sow feces and reduce constipation.

[0021] This invention provides a feed additive, including fermented bamboo powder.

[0022] The present invention discloses the following technical effects: 1. Significant Fiber Structure Destruction and Increased Fermentable Sugar Content: This invention first employs steam explosion + weak alkali technology to pretreat bamboo blocks. Baking soda solution is sprayed onto the bamboo blocks, and pressure is maintained at 1.0-2.5 MPa for 240-480 seconds before being instantly released. The high-pressure saturated steam rapidly penetrates into the bamboo powder, and the sudden pressure release instantly converts the stored heat energy into mechanical work, destroying the supramolecular structure of the plant cell walls. The penetrating baking soda solution further intensifies the destructive effect on plant cells. After this treatment, the free reducing sugar content of the bamboo powder is significantly increased from 0.5-1% to 8-10%, providing a sufficient initial readily available carbon source for subsequent microbial fermentation and significantly improving fermentation efficiency.

[0023] 2. Optimized nutritional formula and balanced carbon-nitrogen ratio: This invention adds organic protein sources such as soybean meal and cottonseed meal, or inorganic protein sources such as urea, to ensure that the crude protein content of the fermentation substrate is not less than 3.5%, and the carbon-nitrogen ratio is controlled to not exceed 80:1. This optimized ratio provides balanced nutrition for microorganisms and ensures that the crude protein content of the final fermented product, based on air-dried matter, is increased to over 6%, significantly improving the nutritional deficiencies of fermented bamboo powder as a single fiber raw material.

[0024] 3. Highly Efficient Fiber Degradation and Quality Improvement through Synergistic Effect of Microorganisms and Enzymes: This invention utilizes the synergistic effects of four strains—Bacillus subtilis, Aspergillus niger, Lactobacillus plantarum, and Saccharomyces cerevisiae—in a chain of "fiber degradation-acid production and antibacterial activity-protein proliferation-functional improvement" by screening and optimizing the ratio of Bacillus subtilis, Aspergillus niger, Lactobacillus plantarum, and Saccharomyces cerevisiae, along with the innovative addition of adsorbed and immobilized cellulase to extend enzyme activity preservation time and improve the synergistic fermentation effect of microorganisms and enzymes. Cellulase can effectively hydrolyze the β-1,4-glycosidic bonds in cellulose, degrading cellulose in plant cell walls into fermentable sugars, forming a complementary and synergistic effect with the enzyme system secreted by microorganisms. The bamboo powder adsorption and immobilization treatment allows the enzyme protein to concentrate its action on the fiber substrate in the early stage of fermentation, while the porous structure provides a microenvironment that mitigates the inhibitory effect of the acidic fermentation environment on enzyme activity. After 48 hours of fermentation, the pH drops to 4.4-4.8, and after 72 hours, it further drops to 3.6-4.0, with the acidic environment effectively inhibiting contamination by other microorganisms. Fermented bamboo powder has a crude protein content of over 6% based on air-dried matter, a bamboo-sour aroma, and a total dietary fiber content of over 70%. It has a soft texture, no thorny feel, and significantly improved palatability.

[0025] 4. Excellent feeding effect on ruminants: When the product of this invention is added to the diet of beef cattle at a weight ratio of 10%-30% to replace roughage such as straw and silage, animal experiments show that the average daily weight gain of beef cattle tends to increase, the feed conversion ratio is significantly reduced, and the utilization rate of crude fiber nutrients is effectively improved.

[0026] 5. Significant effects on monogastric animals: Adding 2.5%-5.0% of the product of this invention to the diet of peripartum sows to replace bran, rice bran meal and other fiber raw materials has shown in animal experiments (see Example 4) that adding fermented bamboo powder can significantly increase the moisture content and pH value of sow feces, improve sow feed intake and relieve constipation. The recommended addition ratio is 5.0% of the weight of the basic feed.

[0027] 6. Raw materials are readily available, the process is environmentally friendly, and it is safe for feed use: This invention makes full use of my country's abundant bamboo resources, employing a process combining steam explosion and solid-state fermentation, which is green and pollution-free. The mycotoxin content of fermented bamboo powder is significantly lower than that of traditional fiber raw materials such as wheat straw and bran, and it has a soft texture and high safety for feed use. Applying the optimized fermented bamboo powder to improve the growth performance and nutrient utilization of ruminants (such as beef cattle) and enhance the intestinal health of monogastric animals (such as sows) has not been sufficiently reported in existing technologies, and this invention demonstrates the superior effects of fermented bamboo powder. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The figure shows the effect of fermented bamboo powder of the present invention on the growth performance of beef cattle. In the figure, A is the average daily weight gain (ADG), B is the average daily dry matter intake (DMI), and C is the feed conversion ratio (F / G). Figure 2 This is a graph showing the effect of fermented bamboo powder of the present invention on the apparent digestibility of nutrients in beef cattle, where DM represents dry matter; EE represents crude fat; Ash represents ash; and CF represents crude fiber. Figure 3 This is a graph showing the effect of fermented bamboo powder of the present invention on the moisture content of sow feces; Figure 4 This is a diagram showing the effect of fermented bamboo powder of the present invention on the pH of sow feces; Figures 1-4 Different letters in the middle indicate significant differences between groups. P <0.05), the same letter or no letter indicates that the difference between groups is not significant ( P> 0.05). Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0033] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0034] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0035] The cellulase was purchased from Shandong Longkete Enzyme Preparation Co., Ltd., and its enzyme activity was 20,000 U / g.

[0036] Bacillus subtilis was purchased from the China Agricultural Microbial Culture Collection Center, strain number ACCC 64575.

[0037] Aspergillus niger was purchased from the China Agricultural Microbial Culture Collection Center, strain number ACCC 30936.

[0038] Lactobacillus plantarum was purchased from the China Agricultural Microbial Culture Collection Center, strain number ACCC 11016.

[0039] The brewing yeast was purchased from the China Agricultural Microbial Culture Collection Center, strain number ACCC 21179.

[0040] Example 1: Preparation of Fermented Bamboo Powder 1. Steam Explosion Pretreatment: Fresh culms of 3-year-old moso bamboo were taken, branches, leaves, and roots were removed, and the bamboo was cut into pieces of about 4cm using a crusher. Baking soda (0.5% of the bamboo piece weight) was dissolved in water and sprayed onto the surface of the bamboo pieces. The bamboo pieces were then placed in a steam explosion device and maintained at 1.5 MPa for 360 seconds before being depressurized instantly. The exploded material was dried at 65℃ to a moisture content of 40%, pulverized, and passed through a 20-mesh sieve to obtain steam-exploded bamboo powder. Measurements showed that the reducing sugar content of the bamboo powder after steam explosion pretreatment increased from 0.52% to 9.57%.

[0041] 2. Preparation of fermentation substrate: Weigh 92.5 kg of steam-blasted bamboo powder, 5 kg of soybean meal, 0.5 kg of urea (feed grade), add 2 kg of molasses (molasses sugar content 48%), and add purified water to adjust the total moisture content to 40%. Mix thoroughly to achieve a crude protein content of 5.03% and a carbon-to-nitrogen ratio of approximately 55:1.

[0042] 3. Preparation of compound microbial agents: Bacillus subtilis was inoculated into LB liquid medium and cultured at 37°C and 180 rpm for 24 h to obtain approximately 6 × 10⁻⁶ viable bacteria. 8 CFU / mL bacterial suspension.

[0043] Aspergillus niger was inoculated into PDA liquid medium and cultured at 30°C and 150 rpm for 72 h to obtain approximately 4 × 10⁻⁶ viable bacteria. 5 CFU / mL spore suspension.

[0044] Lactobacillus plantarum was inoculated into MRS liquid medium and incubated statically at 37°C for 48 hours, yielding approximately 2.5 × 10⁻⁶ viable bacteria. 9 CFU / mL bacterial suspension.

[0045] Saccharomyces cerevisiae was inoculated into YPD liquid medium and cultured at 30°C and 180 rpm for 48 hours, yielding approximately 1.5 × 10⁻⁶ viable cells. 9 CFU / mL bacterial suspension.

[0046] The above four bacterial solutions were mixed in a volume ratio of 1:1:1:1 to obtain a compound bacterial agent, wherein the total number of effective viable bacteria was not less than 10. 8 CFU / mL.

[0047] 4. Preparation of adsorbed and immobilized cellulase: The steam-blasted bamboo powder obtained in step 1 was dried to a moisture content of 18%, and then ultra-finely pulverized to D using an impact mill. 95The target particle size was 50 micrometers (300 mesh). A citrate buffer solution with a pH of 4.8 was sprayed onto the bamboo powder to allow it to swell; the spraying amount was 20% of the base material weight. Cellulase was dissolved in the citrate buffer solution with a pH of 4.8 to obtain an enzyme solution with a concentration of 20,000 U / mL. The enzyme solution was evenly sprayed into the steam-exploded bamboo powder at a volume-to-mass ratio of 0.5 mL:1 g, stirred at 150 rpm for 30 min, and then allowed to stand at 25-30℃ for 2 h to allow the enzyme to fully penetrate the micropores of the bamboo fibers. Afterward, the bamboo was dried at 50℃ until the moisture content reached 10%, allowing the enzyme protein to be locked within the micropores of the bamboo fibers, resulting in immobilized cellulase with an enzyme activity of 10,000 U / g.

[0048] 5. Solid-state fermentation: The above-mentioned compound microbial agent and immobilized cellulase are added to the fermentation substrate. The inoculum amount of the compound microbial agent is 5% of the dry weight of the bamboo powder substrate; simultaneously, the amount of immobilized cellulase added is 25 U / g per gram of steam-exploded bamboo powder (dry weight). After thorough mixing, the mixture is placed in a sealed solid-state fermentation tank with a substrate thickness of 1.2 m. Turning is performed once the fermentation substrate temperature exceeds 45℃. The fermentation environment temperature is 30℃, and the fermentation time is 72 hours. The pH drops to 4.45 after 48 hours of fermentation and to 3.65 after 72 hours. There is no fixed number of turnings; turning once when the temperature exceeds 45℃ is sufficient to lower the temperature. In the early stages of operation, one turning can lower the temperature by 5-10℃.

[0049] 6. Post-processing: After fermentation, the fermentation product is divided into sealed bags, compacted, vacuum-sealed, and stored at room temperature to obtain the wet fermented bamboo powder product.

[0050] The fermentation product was dried in a 65°C low-temperature dryer until the moisture content was 12%, and then crushed through an 80-mesh sieve using a hammer mill to obtain the dry fermented bamboo powder product.

[0051] According to the test results, the fermented bamboo powder product has a crude protein content of 6.27% based on air-dried matter, has a bamboo acid aroma, a total dietary fiber content of 70.24%, and a soft texture without any needle-like feel.

[0052] Application Example 1: Analysis of the Physicochemical Properties of Fermented Bamboo Powder The dry fermented bamboo powder product prepared in Example 1 was used to determine its key physicochemical indicators, and compared with conventional bamboo powder (dried bamboo chips pulverized by a hammer mill and passed through an 80-mesh sieve). The testing methods were based on relevant national standard methods.

[0053] The results are shown in Table 1. Compared with conventional bamboo powder, the dry fermented bamboo powder prepared in Example 1 of this invention showed significant improvements in fiber properties such as water-holding capacity, oil-holding capacity, water absorption and swelling capacity, and water binding capacity. In terms of nutritional indicators, fermentation treatment significantly increased the crude protein content of the bamboo powder and significantly reduced the total dietary fiber content. No aflatoxin B1 or zearalenone mycotoxins were detected.

[0054] Table 1 Physicochemical properties of fermented bamboo powder and conventional bamboo powder Note: Different letters in the same row indicate significant differences between groups (P<0.05), while the same letter in the same row indicates no significant differences between groups (P>0.05).

[0055] Application Example 2 To verify the synergistic effect of bacteria and enzymes, the following three groups of different fermentation additive schemes were set up. The fermentation substrate and process parameters were the same as those in Example 1. The design and treatment of each group were as follows: Group A: Added compound bacterial agent (5%), without adding cellulase; Group B: Added compound bacterial agent (5%) + 25 U / g cellulase (without adsorption and immobilization treatment); Group C: Same as in Example 1.

[0056] After fermentation, the fermentation product was prepared into finished dry fermented bamboo powder using the method described in Example 1.

[0057] Products A, B, and C were taken, and their physicochemical indicators, including reducing sugar, crude protein, acid-soluble protein, and crude fiber degradation rate, were determined. The crude protein content was determined according to GB / T 6432-2018 "Determination of Crude Protein in Feed - Kjeldahl Method"; the crude fiber content was determined according to GB / T 6434-2022 "Determination of Crude Fiber Content in Feed"; the acid-soluble protein content was determined according to NY / T 3801-2020 "Determination of Acid-Soluble Protein in Feed Raw Materials"; and the reducing sugar content was determined according to GB 5009.7-2016 "National Food Safety Standard - Determination of Reducing Sugar in Food". The crude fiber degradation rate was calculated using the following formula: Crude fiber degradation rate (%) = (Crude fiber content before fermentation - Crude fiber content after fermentation) / Crude fiber content before fermentation × 100%. The test results are shown in Table 2. Table 2 shows that, in terms of the degradation rates of reducing sugar, crude protein, acid-soluble protein, and crude fiber, group C > group B > group A. Specifically, the degradation rates of reducing sugar, crude protein, and crude fiber in group C were significantly higher than those in groups A and B. P The content of acid-soluble protein and the degradation rate of crude fiber in group B were significantly higher than those in group A (<0.05). This indicates that fermented bamboo powder exhibits a synergistic effect between bacteria and enzymes, and the adsorbed and immobilized cellulase also showed better application effects than conventional cellulase.

[0058] Table 2. Effects of different additives on the physicochemical properties of fermented bamboo powder Note: Different letters on the same line indicate significant differences between groups. P <0.05, with the same letter on the shoulder indicating no significant difference between groups ( P >0.05).

[0059] Application Example 3: Application of Fermented Bamboo Powder in Beef Cattle Farming This application example verifies the effect of the wet fermented bamboo powder prepared in Example 1 of the present invention in beef cattle feed.

[0060] Experimental Design: Ten healthy Simmental crossbred beef cattle of similar weight were randomly divided into two groups of five each. The control group (CON) was fed a basal diet (containing wheat straw and corn silage), while the experimental group (TRE) had 20% by weight of the wet-fermented bamboo powder prepared in Example 1 added to the basal diet, replacing wheat straw and corn silage in equal amounts. The pre-trial period was 7 days, and the formal trial period was 60 days.

[0061] Growth performance determination: Record initial weight, final weight, and feed intake, and calculate average daily gain (ADG) and feed conversion ratio (F / G).

[0062] Nutrient apparent digestibility determination: Fresh feces were collected for 3 consecutive days at the end of the experiment, and the apparent digestibility of dry matter, crude fiber, crude fat and crude ash was determined by endogenous indicator method.

[0063] Experimental results: 1. Growth performance: such as Figure 1 As shown, compared with the control group, the average daily weight gain (ADG) of the experimental group of beef cattle increased by 19.85% and the feed conversion ratio (F / G) decreased significantly by 21.08%.

[0064] 2. Apparent nutrient digestibility: such as Figure 2 As shown, compared with the control group, the apparent digestibility of crude fiber (CF) in the experimental group of beef cattle was significantly increased, while the apparent digestibility of dry matter (DM), crude fat (EE), and crude ash (ASH) was not significantly different from that in the control group.

[0065] The above results indicate that the fermented bamboo powder prepared by this invention can improve the fiber digestibility and utilization of beef cattle and promote growth.

[0066] Application Example 4: Application of Fermented Bamboo Powder in Sow Feed This application example verifies the effect of the dry fermented bamboo powder prepared in Example 1 of the present invention in sow feed.

[0067] Experimental Design: Thirty healthy Landrace × Large White crossbred sows in moderate body condition, with two parities and the same expected farrowing date, were selected and randomly divided into three groups, with 10 replicates per group and one sow per replicate. The control group was fed a corn-soybean meal-bran-based diet. Experimental groups 1 and 2 were fed the control diet supplemented with 2.5% and 5% dry fermented bamboo powder by weight, respectively, replacing bran with an equal amount of total dietary fiber and adjusting the protein level with corn and soybean meal. The pre-feeding period was 3 days, and the formal experiment lasted from day 107 of gestation to day 7 postpartum. Sows were fed twice daily (6:30 AM and 3:30 PM). From day 107 of gestation until farrowing, they were fed 3 kg of feed daily. For the first 7 days postpartum, the feed was increased incrementally, starting with 1 kg on the first day after farrowing and increasing by 1 kg daily thereafter.

[0068] Fecal physicochemical determination: Fresh samples were collected from all test sows on days 5-7 postpartum and placed in sample bags, then frozen at -20℃ for the physicochemical indicators to be measured. Approximately 200g of the -20℃ frozen feces was thawed at room temperature and dried at 103℃ for 72 hours. The weight of the sample before and after drying was measured, and the fecal moisture percentage was calculated. 0.5g of thawed feces was placed in a beaker, and 20mL of distilled water was added. After thorough stirring and standing, the pH value of the feces was measured.

[0069] Experimental results: 1. Fecal moisture content: such as Figure 3 As shown, with the increase of fermented bamboo powder addition level, the moisture content of sow feces increased significantly, reducing the occurrence of constipation. Among them, the moisture content of sow feces in the 5.0% dry fermented bamboo powder group was significantly higher than that in the control group and higher than that in the 2.5% dry fermented bamboo powder group.

[0070] 2. Fecal pH: such as Figure 4 As shown, fermented bamboo powder increased the pH of sow feces, with the pH of sow feces in experimental groups 1 and 2 being significantly higher than that in the control group. The slight increase in fecal pH in the fermented bamboo powder group may be due to accelerated intestinal peristalsis, reduced reabsorption of organic acids, and increased fecal moisture content, suggesting that fermented bamboo powder may improve sow feed intake and reduce constipation by enhancing intestinal motility, thus alleviating constipation in sows.

[0071] Application prospects: The fermented bamboo powder of this invention has good application prospects in sow feed and can replace wheat bran or rice bran meal in equal amounts according to the total dietary fiber content.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing fermented bamboo powder, characterized in that, Includes the following steps: Step 1: Preparation of fermentation substrate: Mix the steam-exploded bamboo powder with the nutrient additives evenly to obtain the fermentation substrate; Step 2: Preparation of adsorbed and immobilized cellulase: Citrate buffer and cellulase solution are sprayed sequentially onto the steam-blasted bamboo powder. The volume ratio of the cellulase solution to the mass ratio of the steam-blasted bamboo powder is 0.5-1 mL:1 g. After spraying the cellulase solution, the mixture is stirred, allowed to stand, and dried sequentially to obtain the adsorbed and immobilized cellulase. The enzyme activity of the adsorbed and immobilized cellulase is ≥10,000 U / g. Step 3: Preparation and solid-state fermentation of compound microbial agent: Bacillus subtilis ( Bacillus subtilis Aspergillus niger ( ) Aspergillus niger Lactobacillus plantarum ( Lactobacillus plantarum ) and brewer's yeast ( Saccharomyces cerevisiae The bacterial solutions were mixed evenly in a volume ratio of 1:1:1:1 to obtain the compound bacterial agent, wherein the total number of effective viable bacteria in the compound bacterial agent is not less than 10. 8 CFU / mL; The compound bacterial agent and the adsorbed and immobilized cellulase were added to the fermentation substrate to carry out solid-state fermentation to obtain the fermentation product; Step 4: Encapsulate the fermentation product to obtain wet fermented bamboo powder; and / or, dry, pulverize and sieve the fermentation product to obtain dry fermented bamboo powder.

2. The preparation method according to claim 1, characterized in that, The method for preparing the steam-exploded bamboo powder includes: blasting bamboo raw materials to obtain steam-exploded bamboo powder; the bamboo raw materials are 2-6 year old moso bamboo (… Phyllostachys edulis Fresh bamboo stalks are broken into pieces 3-5 cm in length.

3. The preparation method according to claim 2, characterized in that, The blasting process is carried out at a pressure of 1.0-2.5 MPa for 240-480 s; the blasted material is dried to a moisture content of 35%-40%, pulverized through a 20-mesh sieve, and the steam-blasted bamboo powder is obtained.

4. The preparation method according to claim 1, characterized in that, In step 1, the weight percentage of each raw material in the fermentation substrate, based on dry matter, is as follows: 90%-95% steam-exploded bamboo powder, 0-5% soybean meal, 0-5% cottonseed meal, 0-1% urea, and 0%-5% molasses. In step 2, the stirring speed is 100-200 rpm and the time is 30 min; the settling temperature is 25-30℃ and the time is 2-4 h; the drying method includes drying, and the drying temperature is 45-50℃.

5. The preparation method according to claim 1, characterized in that, In step 3, the inoculation amount of the compound microbial agent is 5%-8% of the dry weight of the steam-exploded bamboo powder, and the amount of adsorbed and immobilized cellulase added is 10-50 U of enzyme activity units per gram of steam-exploded bamboo powder; the thickness of the solid-state fermentation material is 1.2-1.5 m, and the fermentation material is turned over after the temperature exceeds 45℃; the fermentation environment temperature is 28-32℃, and the fermentation time is 72-96 h; after 48 h of fermentation, the pH drops to 4.4-4.8, and after 72 h of fermentation, the pH drops to 3.6-4.0, and then the pH tends to stabilize.

6. The preparation method according to claim 1, characterized in that, In step 4, the drying temperature is 60-70℃, and the product is dried until the moisture content is ≤14%, and then pulverized through a 60-80 mesh sieve.

7. A wet-fermented bamboo powder or dry-fermented bamboo powder prepared by the preparation method according to any one of claims 1-6.

8. The application of the fermented bamboo powder of claim 7 in the preparation of ruminant feed, characterized in that, Add 10%-30% by weight of the aforementioned wet fermented bamboo powder to the basal diet of the ruminants.

9. The application of the fermented bamboo powder of claim 7 in the preparation of monogastric animal feed, characterized in that, Add 2.5%-5.0% by weight of the aforementioned dry fermented bamboo powder to the basal diet of the monogastric animals.

10. A feed additive, characterized in that, Includes the wet-fermented bamboo powder or dry-fermented bamboo powder as described in claim 7.

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