Straw high-value feed preparation method based on synergistic effect of bacteria and enzymes

Abstract

This invention relates to the field of fermented feed preparation technology, and more particularly to a method for preparing high-value straw feed based on the synergistic effect of bacteria and enzymes. The method includes the following steps: mixing a compound enzyme preparation with straw raw materials, allowing static enzymatic hydrolysis to obtain enzymatically hydrolyzed material; inoculating the obtained enzymatically hydrolyzed material with aerobic fermentation bacteria, and carrying out aerobic fermentation under aerobic conditions; and inoculating the obtained aerobic fermentation material with anaerobic bacteria, and carrying out anaerobic fermentation under anaerobic conditions. The high-value straw feed prepared by this invention has shown outstanding growth-promoting effects in yak and Tibetan sheep farming, significantly improving daily weight gain, slaughter rate, and net meat ratio, while also improving meat quality indicators such as marbling score, water retention rate, and tenderness. The development of this feed effectively solves the problems of insufficient supply of high-quality roughage and high farming costs, and realizes the efficient resource utilization of agricultural waste straw, possessing both economic benefits and ecological environmental protection value.

Description

Technical Field

[0001] This invention relates to the field of fermented feed preparation technology, and in particular to a method for preparing high-value straw feed based on the synergistic effect of bacteria and enzymes. Background Technology

[0002] Currently, a large amount of crop straw is produced annually, with barley straw, oat straw, triticale straw, and corn straw being the main agricultural byproducts. Gannan Prefecture, as an important livestock breeding area, is rich in barley straw resources, but its resource utilization rate has long been low, with large amounts of straw being directly discarded or burned, causing environmental pollution and resource waste. At the same time, the supply of high-quality roughage for yak and Tibetan sheep farming in the area is insufficient, resulting in high breeding costs. Therefore, there is an urgent need to develop efficient and low-cost straw feed utilization technologies.

[0003] Currently, the main methods for processing straw into feed include physical crushing, chemical alkali treatment, and microbial fermentation. Among these, microbial fermentation has received widespread attention due to its environmental friendliness and relatively simple operation. Existing microbial fermentation technologies mostly use single-strain or simply compounded inoculants for solid-state fermentation. Commonly used strains include Aspergillus niger, Trichoderma viride, yeast, and lactic acid bacteria. However, due to the dense waxy layer and lignin structure on the surface of straw, microorganisms have difficulty quickly penetrating the straw interior, resulting in long fermentation start-up times and low degradation efficiency. Some technologies attempt to add exogenous enzyme preparations during fermentation to assist degradation, but the order of enzyme and bacteria addition and the synergistic mechanism lack systematic design, leading to unstable results.

[0004] For straw with high silicon content (such as barley straw), there are currently no fermentation methods specifically designed to address its silicon content characteristics. The presence of silicon makes the straw hard and less palatable, and conventional fermentation processes are insufficient to effectively soften its structure, affecting ruminants' feeding and digestion. Furthermore, existing fermentation processes often employ single-stage static fermentation, which cannot simultaneously meet the different oxygen requirements for aerobic bacterial propagation and anaerobic bacterial metabolism, resulting in insufficient bacterial activity and limited improvement in feed protein content.

[0005] Therefore, developing a method for preparing straw feed that can quickly initiate fermentation, efficiently degrade straw fiber, significantly increase feed protein content, and has a good softening effect on straw with high silicon content is of great practical significance and application value. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing high-value straw feed based on the synergistic effect of bacteria and enzymes. This addresses the problems of slow fermentation start-up, low degradation efficiency, and insufficient improvement in feed protein content in existing straw fermentation feed preparation methods.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing high-value straw feed based on the synergistic effect of bacteria and enzymes, comprising the following steps: (1) Enzymatic hydrolysis: The compound enzyme preparation is mixed with straw raw material and allowed to stand for enzymatic hydrolysis to obtain enzymatic hydrolysate; the compound enzyme preparation contains laccase, manganese peroxidase and cellobiose dehydrogenase; (2) Aerobic fermentation: Aerobic fermentation bacteria are inoculated into the enzymatic hydrolysate obtained in step (1) and aerobic fermentation is carried out under aerobic conditions; the aerobic fermentation bacteria include silicate-degrading bacteria (Shandong Nuojie Biotechnology Co., Ltd.), Aspergillus niger (Yiyuan Kangyuan Biotechnology Co., Ltd.), Trichoderma viride (Shanghai Baililai Biotechnology Co., Ltd.) and thermophilic pyridobacterium (Beijing Bio-Biotech Co., Ltd.). (3) Anaerobic fermentation: Anaerobic bacteria are inoculated into the aerobic fermentation material obtained in step (2) and anaerobic fermentation is carried out under anaerobic conditions; the anaerobic bacteria include Candida utilis (Wuhan Haorong Biotechnology Co., Ltd.), lactic acid bacteria (Hubei Languzhong Microbial Technology Co., Ltd.) and Clostridium butyricum (Wuhan Xinhua Yang Biotechnology Co., Ltd.).

[0008] Preferably, the straw raw material in step (1) is barley straw, oat straw, rye straw or corn straw; the mass of the compound enzyme preparation added is 0.5~1.5%.

[0009] Preferably, before step (1), the straw raw material is further subjected to pretreatment, including crushing and adjusting the moisture content to 50%~70%.

[0010] Preferably, the enzymatic hydrolysis treatment in step (1) takes 2 to 4 hours and the temperature is 25°C to 35°C.

[0011] Preferably, the conditions for aerobic fermentation in step (2) are: temperature 25℃~35℃, time 2~5 days; and the mass of aerobic fermentation bacteria added is 2~3%.

[0012] Preferably, the anaerobic fermentation conditions in step (3) are: temperature 20℃~30℃, time 5~10 days; the mass of anaerobic bacteria added is 2.5~3.5%.

[0013] Preferably, the mass ratio of laccase, manganese peroxidase and cellobiose dehydrogenase in step (1) is 1~3:1:1.

[0014] Preferably, the mass ratio of silicate-degrading bacteria, Aspergillus niger, Trichoderma viride and thermophilic filamentous fungi in step (2) is 1~3:1~3:1~3:1~3, and the bacterial count is 4~600 million / g.

[0015] Preferably, the mass ratio of Candida utilis, lactic acid bacteria and Clostridium butyricum in step (3) is 5~9:4~6:10~15, and the bacterial count of each is 400 million to 600 million / g.

[0016] Furthermore, this invention integrates the concept of substrate supplementation into its synergistic microbial-enzyme strategy. Through the synergistic effect of pre-enzymatic hydrolysis with compound enzyme preparations and subsequent multi-stage fermentation, it indirectly simulates the effect of "sugar-supplemented substrate," effectively alleviating the problems of slow start-up and insufficient acidification caused by insufficient fermentable substrates in the early stages of fermentation of high-fiber, low-soluble carbohydrate straw (such as barley straw). Compared with existing silage technologies that rely on single microbial agents or enzyme preparations, this invention achieves a similar comprehensive effect of "microbial-induced acidification and enzyme-induced degradation" without the need for additional exogenous carbon sources such as molasses. It promotes the rapid accumulation of organic acids such as lactic acid, significantly reduces pH, thereby inhibiting the reproduction of molds and yeasts, reducing the risk of mold growth, and ensuring the fermentation quality and storage stability of the feed.

[0017] Therefore, this invention specifically addresses the need for high-value utilization of unique straw resources in high-altitude and cold regions (such as Gannan). Through an aerobic-anaerobic staged fermentation process, it not only solves the problems of unstable quality and significant nutrient loss associated with traditional natural silage, but also significantly improves the crude protein content and palatability of the feed. This technical approach is both regionally adaptable and universally applicable, capable of converting low-moisture, high-fiber straw raw materials into high-quality roughage, effectively replacing some concentrate feed, reducing breeding costs, and providing an operable technical path for the green and circular development of the grass-livestock industry. It has broad prospects for widespread application in similar ecological zones for the utilization of straw resources.

[0018] This invention provides a method for preparing high-value straw feed.

[0019] Compared with the prior art, the present invention has the following beneficial effects: First, this invention pre-mixes and enzymatically hydrolyzes a composite enzyme preparation consisting of laccase, manganese peroxidase, and cellobiose dehydrogenase with straw raw materials. This rapidly breaks down the waxy layer and dense lignin structure on the surface of the straw, creating favorable conditions for subsequent microbial invasion into the straw. This synergistic microbial-enzyme approach significantly shortens the fermentation start-up time and improves the degradation efficiency of straw fibers, overcoming the shortcomings of slow fermentation start-up and insufficient degradation associated with traditional single-strain or simple compound microbial agents.

[0020] Secondly, this invention specifically introduces silicate-degrading bacteria during the aerobic fermentation stage, targeting the characteristics of high-silica straw (such as barley straw). Combined with the synergistic effect of Aspergillus niger, Trichoderma viride, and thermophilic pyriformis, it effectively softens the texture of the straw, reduces the adverse effects of silicon content on feeding and digestion, significantly improves the palatability of the feed, and makes the treated straw easier for ruminants to eat and digest.

[0021] Third, this invention employs a multi-stage dynamic process of aerobic fermentation followed by anaerobic fermentation. The aerobic stage promotes the rapid proliferation of enzyme-producing strains and the secretion of large amounts of endogenous enzymes, which work synergistically with exogenous enzymes to efficiently degrade fibers. In the anaerobic stage, Candida utilis, lactic acid bacteria, and Clostridium butyricum are used to convert sugars into microbial proteins and organic acids, which not only significantly increases the protein content of the feed but also inhibits contamination by other microorganisms through lactic acid accumulation and generates flavor substances such as esters, giving the feed a unique fruity aroma.

[0022] Fourth, the high-value straw feed prepared by this invention exhibits outstanding growth-promoting effects in yak and Tibetan sheep farming, significantly increasing daily weight gain, slaughter rate, and lean meat ratio, while also improving meat quality indicators such as marbling score, water retention rate, and tenderness. Compared with existing technologies and conventional basic feeds, this invention effectively solves the problems of insufficient supply of high-quality roughage and high farming costs, and achieves efficient resource utilization of agricultural waste straw, possessing both economic benefits and ecological environmental value.

[0023] Fifth, this invention further addresses the specific characteristics of barley straw and other raw materials in the Gannan region, which have low moisture content, high fiber content, and insufficient soluble carbohydrates. Through a synergistic design of "microbial-induced acidification, enzymatic degradation, and sugar-supplemented substrate," it effectively solves prominent problems such as slow fermentation initiation, insufficient acidification, and the proliferation of mold and yeast during natural silage. Specifically, the compound enzyme preparation pre-disrupts the lignocellulose barrier, creating conditions for rapid colonization by aerobic and anaerobic bacteria. Functional strains such as silicate-degrading bacteria introduced during the aerobic fermentation stage synergistically degrade silica and fiber, softening the straw. During the anaerobic fermentation stage, lactic acid bacteria rapidly produce acid to lower the pH, while Clostridium butyricum and Candida utilis further convert sugars into microbial proteins and organic acids, forming a stable acidic environment that inhibits the growth of other microorganisms. This technical approach is not only applicable to ordinary straw but is particularly suitable for the feed utilization of low-moisture, high-fiber barley straw in high-altitude and cold regions. It can significantly improve the quality of silage fermentation, nutrient retention rate, and microbial safety, providing a reliable technical path for ensuring high-quality roughage during the cold season and for the green and circular development of the forage-livestock industry. Detailed Implementation

[0024] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0025] Example 1

[0026] The experimental site for this invention was located in Gannan Prefecture. Highland barley straw was taken, crushed to a particle size of 2-3 cm, and the moisture content was adjusted to 70%. 1.5% of a compound enzyme preparation was added based on the mass of the straw raw material. The mass ratio of laccase, manganese peroxidase, and cellobiose dehydrogenase in the compound enzyme preparation was 3:1:1. The mixture was allowed to stand at 35°C for 4 hours for enzymatic hydrolysis to obtain the hydrolysate.

[0027] Aerobic fermentation bacteria were inoculated into the obtained enzymatic hydrolysate at an inoculation rate of 3% (based on the mass of the enzymatic hydrolysate). The aerobic fermentation bacteria consisted of a mixture of silicate-solubilizing bacteria, Aspergillus niger, Trichoderma viride, and Thermophilus pyridostigma in a mass ratio of 3:3:3:3, with each bacteria containing 600 million CFU / g. Fermentation was carried out at 35°C under aerobic conditions for 5 days to obtain the aerobic fermented material.

[0028] Anaerobic bacteria were evenly sprayed onto the obtained aerobic fermentation material at an inoculation rate of 3.5% (based on the mass of the aerobic fermentation material). The anaerobic bacteria were a mixture of Candida utilis, lactic acid bacteria, and Clostridium butyricum in a mass ratio of 9:6:15, with a bacterial count of 600 million / g for each. Fermentation was carried out at 30℃ under anaerobic conditions for 10 days after coating to obtain high-value straw feed.

[0029] Example 2

[0030] The experimental site for this invention was located in Gannan Prefecture. Triticale straw was taken, crushed to a particle size of 2-3 cm, and the moisture content was adjusted to 50%. 0.5% of a compound enzyme preparation was added based on the mass of the straw raw material. The mass ratio of laccase, manganese peroxidase, and cellobiose dehydrogenase in the compound enzyme preparation was 1:1:1. The mixture was allowed to stand at 25°C for 2 hours for enzymatic hydrolysis to obtain the hydrolysate.

[0031] Aerobic fermentation bacteria were inoculated into the obtained enzymatic hydrolysate at an inoculation rate of 2% (based on the mass of the enzymatic hydrolysate). The aerobic fermentation bacteria consisted of a mixture of silicate-degrading bacteria, Aspergillus niger, Trichoderma viride, and Thermophilus pyridostigma in a mass ratio of 1:1:1:1, with a bacterial count of 400 million / g for each. Fermentation was carried out at 25℃ under aerobic conditions for 2 days to obtain the aerobic fermented material.

[0032] Anaerobic bacteria were evenly sprayed onto the obtained aerobic fermentation material at an inoculation rate of 2.5% (based on the mass of the aerobic fermentation material). The anaerobic bacteria were a mixture of Candida utilis, lactic acid bacteria, and Clostridium butyricum in a mass ratio of 5:4:10, with a bacterial count of 400 million / g for each. Fermentation was carried out at 20℃ under anaerobic conditions for 5 days after coating to obtain high-value straw feed.

[0033] Example 3

[0034] The experimental site for this invention was located in Gannan Prefecture. Oat straw was taken, crushed to a particle size of 2-3 cm, and the moisture content was adjusted to 55%. 0.7% of a compound enzyme preparation was added based on the mass of the straw raw material. The mass ratio of laccase, manganese peroxidase, and cellobiose dehydrogenase in the compound enzyme preparation was 1.5:1:1. The mixture was allowed to stand at 27°C for 2.5 hours for enzymatic hydrolysis to obtain the hydrolysate.

[0035] Aerobic fermentation bacteria were inoculated into the obtained enzymatic hydrolysate at an inoculation rate of 2.2% (based on the mass of the enzymatic hydrolysate). The aerobic fermentation bacteria were a mixture of silicate-solubilizing bacteria, Aspergillus niger, Trichoderma viride, and Thermophilus pyridostigma in a mass ratio of 1.5:1.5:1.5:1.5, with a bacterial count of 450 million / g for each. Fermentation was carried out at 27℃ under aerobic conditions for 2.5 days to obtain the aerobic fermented material.

[0036] Anaerobic bacteria were evenly sprayed onto the obtained aerobic fermentation material at an inoculum size of 2.7% (based on the mass of the aerobic fermentation material). The anaerobic bacteria were a mixture of *Candida utilis*, *Lactobacillus*, and *Clostridium butyricum* in a mass ratio of 6:4.5:11, with each bacteria containing 450 million CFU / g. Fermentation was carried out at 22℃ under anaerobic conditions for 6 days after coating to obtain high-value straw feed.

[0037] Example 4

[0038] The experimental site for this invention was located in Gannan Prefecture. Highland barley straw was taken, crushed to a particle size of 2-3 cm, and the moisture content was adjusted to 65%. 1.3% of a compound enzyme preparation was added based on the mass of the straw raw material. The mass ratio of laccase, manganese peroxidase, and cellobiose dehydrogenase in the compound enzyme preparation was 2.5:1:1. The mixture was allowed to stand at 33°C for 3.5 hours for enzymatic hydrolysis to obtain the hydrolysate.

[0039] Aerobic fermentation bacteria were evenly sprayed onto the obtained enzymatic hydrolysate at an inoculum size of 2.8% (based on the mass of the enzymatic hydrolysate). The aerobic fermentation bacteria consisted of a mixture of silicate-solubilizing bacteria, Aspergillus niger, Trichoderma viride, and Thermophilus pyriformis in a mass ratio of 2.5:2.5:2.5:2.5, with each bacteria containing 550 million CFU / g. Fermentation was carried out at 33°C under aerobic conditions for 4.5 days to obtain the aerobic fermented material.

[0040] Anaerobic bacteria were inoculated into the obtained aerobic fermentation material at an inoculation rate of 3.3% (based on the mass of the aerobic fermentation material). The anaerobic bacteria were a mixture of *Candida utilis*, lactic acid bacteria, and *Clostridium butyricum* in a mass ratio of 8:5.5:14, with a bacterial count of 550 million / g for each. Fermentation was carried out at 28℃ under anaerobic conditions for 9 days after coating to obtain high-value straw feed.

[0041] Example 5

[0042] The experimental site for this invention was located in Gannan Prefecture. Corn stalks were taken, crushed to a particle size of 2-3 cm, and the moisture content was adjusted to 60%. 1.0% of a compound enzyme preparation was added based on the mass of the stalk raw material. The mass ratio of laccase, manganese peroxidase, and cellobiose dehydrogenase in the compound enzyme preparation was 2:1:1. The mixture was allowed to stand at 30°C for 3 hours for enzymatic hydrolysis to obtain the hydrolysate.

[0043] Aerobic fermentation bacteria were inoculated into the obtained enzymatic hydrolysate at an inoculation rate of 2.5% (based on the mass of the enzymatic hydrolysate). The aerobic fermentation bacteria consisted of a mixture of silicate-degrading bacteria, Aspergillus niger, Trichoderma viride, and Thermophilus pyridostigma in a mass ratio of 2:2:2:2, with each bacteria containing 500 million CFU / g. Fermentation was carried out at 30°C under aerobic conditions for 3.5 days to obtain the aerobic fermented material.

[0044] Anaerobic bacteria were evenly sprayed onto the obtained aerobic fermentation material at an inoculation rate of 3.0% (based on the mass of the aerobic fermentation material). The anaerobic bacteria were a mixture of Candida utilis, lactic acid bacteria, and Clostridium butyricum in a mass ratio of 7:5:12.5, with a bacterial count of 500 million / g for each. Fermentation was carried out at 25℃ under anaerobic conditions for 7.5 days after coating to obtain high-value straw feed.

[0045] Comparative Example 1 The other methods are the same as in Example 5, except that cellobiose dehydrogenase is replaced with manganese peroxidase in equal amounts.

[0046] Comparative Example 2 The other methods are the same as in Example 5, except that the thermophilic cytomegalovirus is replaced with an equal amount of green Trichoderma.

[0047] Comparative Example 3 The other methods are the same as in Example 5, except that Clostridium butyricum is replaced with an equal amount of lactic acid bacteria.

[0048] Experimental Example 1 The experimental yaks, aged 4-5 years, were selected from Haixi Prefecture, Qinghai Province. A total of 120 yaks were randomly divided into 6 groups based on similar weight and age: Example 5 group, Comparative Example 1 group, Comparative Example 2 group, Comparative Example 3 group, Existing Technology group, and Control group. The control group was fed a basal diet (by weight parts): 28 parts corn, 32 parts millet, 12.5 parts soybean meal, 15 parts cottonseed meal, 6.5 parts dried distillers' grains, 1.5 parts fat powder, 1.0 part sodium bicarbonate, 0.6 parts slow-release urea, and 1.0 part molasses. The experimental groups (Example 5 and Comparative Examples 1-3) were fed 35% basal diet plus 65% high-value straw feed prepared according to the corresponding method. The existing technology group was fed 35% basal diet plus 65% corn stalk silage. All groups were fed twice daily, in the morning and afternoon, with free access to water.

[0049] The experiment lasted for 40 days, including a 10-day pre-trial period and a 30-day formal trial period. Each cattle was weighed on the first day of feeding and the day before slaughter to calculate weight gain and average daily weight gain. After the experiment, cattle were slaughtered according to GB / T19477-2004 requirements. Samples of the longissimus dorsi and psoas major muscles were collected within 2-3 hours post-slaughter for subsequent indicator determination.

[0050] Meat production performance was assessed by calculating dressing percentage (carcass weight / live weight before slaughter × 100%) and meat-to-bone ratio (net meat weight / bone weight). Beef quality was assessed by marbling score (the longissimus dorsi muscle at the first lumbar vertebra was cooled at 0-4℃ for 24 hours, then transversely sliced ​​and scored according to the American standard atlas, with a score of 1-5); water retention was assessed using the 35kg pressure method (35kg pressure was applied for 10 minutes, and the weight difference before and after pressure was calculated); tenderness was expressed as shear force value (the longissimus dorsi muscle at the 12th-13th thoracic vertebrae was heated in an 80℃ water bath to a core temperature of 75℃, and measured using a C-LM tenderness meter). The results were averaged and are shown in Tables 1-3.

[0051] Table 1 Weight gain of yaks on the plateau Table 1 shows the weight gain effects of different treatment groups on plateau yaks. Overall, the high-value straw feed prepared in Example 5 of this invention showed the most outstanding performance in terms of yak weight gain and average daily weight gain, significantly better than the comparative examples. In the comparative examples, the decrease in degradation efficiency due to enzyme or bacterial replacement resulted in a progressively weaker weight gain effect, with Comparative Example 3 showing the worst effect. The weight gain effects of the prior art group and the control group were lower than those of all examples and comparative examples, indicating that the method of this invention has a significant promoting effect on yak growth performance.

[0052] Table 2 Properties of Highland Yak Meat Table 2 reflects the dressing percentage and meat-to-bone ratio of yaks in different treatment groups. Example 5 showed the highest dressing percentage and a better meat-to-bone ratio than the other groups, indicating optimal feed conversion efficiency and carcass yield. The dressing percentage and meat-to-bone ratio of each comparative example decreased sequentially, but were still higher than those of the prior art group and the control group. The dressing percentage of the prior art group was slightly lower than that of the control group, but the meat-to-bone ratio was slightly higher. Overall, the feed prepared by the method of this invention can effectively improve the meat production performance of yaks.

[0053] Table 3 Quality of Highland Yak Meat Table 3 compares three key indicators of yak meat quality from the plateau: marbling score, water retention rate, and shear force value. Example 5 achieved the highest levels in both marbling score and water retention rate, while exhibiting the lowest shear force value, indicating the best tenderness, strong water retention, and even distribution of intramuscular fat. The meat quality indicators of the comparative examples decreased sequentially, but were still superior to those of the prior art group and the control group. The prior art group and the control group had higher shear force values ​​and lower water retention rates, demonstrating that the method of this invention can significantly improve the edible quality of beef.

[0054] Experiment Example 2 Sixty Tibetan sheep, approximately 10 months old and weighing between 20 ± 0.5 kg, were randomly divided into six groups based on similar weight and age: Example 5 group, Comparative Example 1 group, Comparative Example 2 group, Comparative Example 3 group, Existing Technology group, and Control group. The Control group was fed a basal diet (by weight parts): 52 parts corn, 31 parts highland barley, 14 parts rapeseed cake, and 1 part salt. The Experimental groups (Example 5 and Comparative Examples 1-3) were fed 35% basal diet plus 65% high-value straw feed prepared according to the corresponding method. The Existing Technology group was fed 35% basal diet plus 65% corn stalk silage. The average daily feeding amount per sheep for fattening was 0.7 kg, divided into two feedings per day.

[0055] The trial lasted 90 days, with days 1-14 being the adaptation period. From day 15 until slaughter, the amount of fattening feed was increased by approximately 10% every two days. Each sheep was weighed on the first day of the trial and the day before slaughter, and the average daily weight gain was calculated. The results were averaged and are shown in Table 4.

[0056] Table 4 Weight gain of Tibetan sheep on the Plateau Table 4 shows the average daily weight gain of Tibetan sheep on the plateau. Example 5 showed the most significant weight gain, far exceeding that of the comparative examples. Among the comparative examples, the weight gain decreased sequentially after enzyme or bacterial strain replacement, with Comparative Example 3 showing the lowest weight gain. The daily weight gain of the prior art group was lower than all examples and comparative examples, and even slightly lower than the control group. This indicates that the method of the present invention is not only applicable to yaks but also has excellent growth-promoting effects on Tibetan sheep on the plateau, making it widely applicable.

[0057] Based on the results in Tables 1 to 4, Example 5 of this invention showed the best performance across all animal test indicators, verifying the effectiveness of the method for preparing high-value straw feed based on the synergistic effect of bacteria and enzymes. Compared with the comparative examples, the specific combination of the three enzymes in the compound enzyme preparation, the addition of *Heterotrophic mycorrhizal* in aerobic fermentation, and the use of *Clostridium butyricum* in anaerobic fermentation are all key technological innovations; any substitution would lead to a decrease in feed effectiveness. Compared with existing technologies and the basic feed control group, the method of this invention significantly improved the weight gain rate, slaughter performance, and meat quality of ruminants, fully demonstrating its superiority and practical application value in the utilization of straw feed. Although the existing technology group nominally used corn stalk silage, this silage did not undergo true microbial fermentation. It relied solely on physical chopping or simple stacking, leaving the dense waxy layer and lignin structure of the straw intact. This made it difficult for cattle and sheep to digest and absorb the fiber components, resulting in significantly low roughage utilization. In contrast, the control group's basal diet, while not containing straw-based roughage, contained corn, millet, and soybean meal that, after being crushed and compounded, had high digestible energy and protein levels. Consequently, in short-term fattening trials, the control group showed slightly higher daily weight gain than the existing technology group. This highlights that the high-value straw feed prepared by this invention through synergistic pretreatment with microorganisms and enzymes and multi-stage aerobic and anaerobic fermentation can truly break down the straw's anti-nutritional barrier and improve digestibility, thus significantly outperforming both the existing technology group and the control group in animal growth performance. It should be noted that the technical solution of this invention is highly consistent with the technical approach for the resource utilization of highland barley straw in Gannan region. Both address the bottleneck problems of low moisture content, high fiber content, and insufficient soluble carbohydrates in straw, employing a synergistic strategy of "bacterial-induced acidification and enzymatic degradation" to accelerate fermentation initiation and improve nutrient preservation. Building upon this, this invention further introduces aerobic-anaerobic multi-stage dynamic fermentation and optimizes specific enzyme components such as laccase, manganese peroxidase, and cellobiose dehydrogenase, as well as functional strains such as silicate-degrading bacteria, thermophilic filamentous bacteria, and butyric acid bacteria. This achieves more efficient fiber breakdown, protein enhancement, and flavor improvement on straw raw materials such as highland barley, oats, and rye, providing a superior technical solution for the supply of high-quality roughage and the green circular development of the forage-livestock industry in high-altitude and cold regions.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing high-value straw feed based on the synergistic effect of bacteria and enzymes, characterized in that, Includes the following steps: (1) Enzymatic hydrolysis: The compound enzyme preparation is mixed with straw raw material and allowed to stand for enzymatic hydrolysis to obtain enzymatic hydrolysate; the compound enzyme preparation contains laccase, manganese peroxidase and cellobiose dehydrogenase; (2) Aerobic fermentation: Aerobic fermentation bacteria are inoculated into the enzymatic hydrolysate obtained in step (1), and aerobic fermentation is carried out under aerobic conditions; the aerobic fermentation bacteria include silicate-degrading bacteria, Aspergillus niger, Trichoderma viride and thermophilic pyriformis; (3) Anaerobic fermentation: Anaerobic bacteria are inoculated into the aerobic fermentation material obtained in step (2) and anaerobic fermentation is carried out under anaerobic conditions; the anaerobic bacteria include Candida utilis, lactic acid bacteria and Clostridium butyricum.

2. The method according to claim 1, characterized in that, The straw raw material mentioned in step (1) is barley straw, oat straw, rye straw or corn straw; the mass of the compound enzyme preparation added is 0.5~1.5%.

3. The method according to claim 1, characterized in that, Step (1) includes pretreatment of the straw raw material by crushing and adjusting the moisture content to 50%~70%.

4. The method according to claim 1, characterized in that, The enzymatic hydrolysis process in step (1) takes 2 to 4 hours and is carried out at a temperature of 25°C to 35°C.

5. The method according to claim 1, characterized in that, The conditions for aerobic fermentation in step (2) are: temperature 25℃~35℃, time 2~5 days; the mass of aerobic fermentation bacteria added is 2~3%.

6. The method according to claim 1, characterized in that, The anaerobic fermentation conditions in step (3) are: temperature 20℃~30℃, time 5~10 days; the mass of anaerobic bacteria added is 2.5~3.5%.

7. The method according to claim 1, characterized in that, The mass ratio of laccase, manganese peroxidase and cellobiose dehydrogenase in step (1) is 1~3:1:

1.

8. The method according to claim 1, characterized in that, The mass ratio of silicate-degrading bacteria, Aspergillus niger, Trichoderma viride and thermophilic filamentous fungi in step (2) is 1~3:1~3:1~3:1~3, and the bacterial count is 4~600 million / g.

9. The method according to claim 1, characterized in that, The mass ratio of Candida utilis, lactic acid bacteria and Clostridium butyricum in step (3) is 5~9:4~6:10~15, and the bacterial count of each is 400 million to 600 million / g.

10. The high-value straw feed prepared by any one of claims 1 to 9.

Images