Low-cost fermented straw silage for beef cattle and preparation method thereof

Abstract

The application discloses a low-cost straw fermentation beef silage and a preparation method thereof. In view of the defects of insufficient soluble sugar, easy enzyme deactivation, high dry matter loss and high production cost of the straw silage, a closed warehouse 2%-5% micro-oxygen section oxygen control process is adopted, and a composite coarse enzyme is used to degrade straw fiber and enrich reducing sugar. After the molasses waste liquid is removed by low-temperature centrifugation, a small amount of the molasses waste liquid is added to activate lactic acid bacteria, modified diatomite is used to stabilize enzyme activity and inhibit secondary fermentation after the silo is opened, the system is naturally converted into an anaerobic environment after micro-oxygen treatment, lactic acid bacteria rapidly acidify the material, and the whole process does not need dehydration. The application is different from the traditional scheme of open inoculation of active bacteria for enzyme production, the obtained silage has low dry matter loss and high feeding safety, the overall preparation cost is greatly reduced, the silage storage stability is good, and the application is suitable for large-scale beef breeding.

Description

Technical Field

[0001] This invention belongs to the field of crop straw resource utilization and beef cattle silage processing technology, specifically relating to a low-cost straw fermented beef cattle silage and its preparation method. Background Technology

[0002] The straw resources of crops such as corn, wheat, and rice are abundant and are high-quality roughage raw materials for beef cattle breeding. However, the straw itself has a dense lignocellulose structure and low endogenous soluble sugar content. Direct silage is prone to problems such as slow fermentation start-up, delayed acidification of the system, and large-scale proliferation of butyric acid putrefactive bacteria. The finished silage product has poor palatability and high nutrient loss. Existing improvement schemes have significant shortcomings: the two-stage fermentation process using live bacteria such as Aspergillus niger for open-air aerobic enzyme production lacks precise oxygen concentration control, and molds and yeasts consume large amounts of reducing sugars produced by fiber degradation, resulting in dry matter loss of over 15%. Furthermore, live fungi are prone to producing mycotoxins, posing safety risks when feeding beef cattle. The silage method of directly adding molasses waste liquid as a carbon source does not undergo impurity removal treatment, and the colloids and soluble salts create a high buffering load, significantly delaying pH decline. Moreover, this scheme is mostly used for biogas fermentation of energy grasses and is not suitable for the feeding needs of beef cattle. Conventional silage with added diatomaceous earth only serves as a physical carrier or insect repellent and cannot protect cellulase activity. When cellulase is added simultaneously in the silo, rapid fermentation and acid production can easily cause enzyme protein inactivation, greatly reducing enzymatic hydrolysis efficiency. In addition, traditional pretreatment processes often involve sun-drying and dehydration, which can easily lead to the loss of small-molecule reducing sugars with the seepage, increasing labor and equipment energy consumption. Furthermore, the procurement cost of commercial food-grade refined enzyme preparations is relatively high, making it difficult to meet the needs of large-scale beef cattle farms for low-cost, low-loss, and highly stable silage production. Summary of the Invention

[0003] To address the shortcomings of existing straw silage, such as high loss, easy enzyme inactivation, poor fermentation stability, and high cost, this invention provides a low-cost straw-fermented beef cattle silage and its preparation method. Through segmented micro-aerobic oxygen control, the synergistic effect of modified diatomaceous earth enzyme stabilization and purified molasses waste liquid, the silage exhibits low loss, stable fermentation, and low cost, making it suitable for large-scale beef cattle farming.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A low-cost straw-fermented silage for beef cattle, based on the weight of straw dry matter, is prepared from the following raw materials in parts by weight: The ingredients are: 100 parts crushed crop straw, 1.5-3 parts compound crude enzyme, 0.5-1.2 parts impurity-removed molasses waste liquid, 0.3-0.8 parts modified diatomaceous earth, and 0.2-0.5 parts compound freeze-dried bacterial powder.

[0005] Preferably, the crop straw is selected from any one or more of corn straw, wheat straw, and rice straw.

[0006] Preferably, the composite crude enzyme is a mixture of cellulase and xylanase in a mass ratio of 1:1.2-1.8; the mass ratio of Lactobacillus plantarum and Lactobacillus buchneri in the composite freeze-dried bacterial powder is 2:1-3:1.

[0007] Preferably, the method for preparing low-cost straw-fermented beef cattle silage includes the following steps: S1. Crush the crop straw to 1-3cm and add water to adjust the material moisture content to 58%-62%; S2. Send the straw into a sealed pretreatment chamber, spray a mixture of compound crude enzyme and centrifuged molasses waste liquid, then add modified diatomaceous earth and mix thoroughly; control the oxygen volume fraction in the chamber to 2%-5% and the temperature to 32-38℃, and let it stand in a sealed chamber for 18-36 hours. S3. Close the air intake of the chamber and let it stand for 6-12 hours until the oxygen in the chamber is completely depleted; S4. The material does not need to be dehydrated. It is inoculated with compound freeze-dried bacterial powder under anaerobic environment, layered, compacted and sealed in pit, and anaerobic fermented for 10-20 days to produce beef cattle silage.

[0008] Preferably, in step S2, the original molasses waste liquid is centrifuged before feeding to obtain the impurity-removed molasses waste liquid. The centrifugation process conditions are: centrifugation at 4000-5000 r / min speed and 4-10℃ low temperature for 10-15 min. The waste liquid after centrifugation is only used as a micronutrient activator for lactic acid bacteria.

[0009] Preferably, in step S2, the mixed liquid is sprayed evenly onto the straw material at 8%-12% of the dry weight of the straw. After spraying, the mixture is continuously stirred for 3-5 minutes. After adding the modified diatomaceous earth, the mixture is stirred for another 2 minutes to ensure that the enzyme solution and diatomaceous earth are evenly soaked and dispersed in the pores inside the straw fibers.

[0010] Preferably, the entire preparation process does not require sun drying or dehydration by squeezing, thus avoiding the loss of reducing sugars.

[0011] The beneficial effects of this invention are as follows: the dry matter loss of the beef cattle silage prepared by this invention is ≤6%, effectively inhibiting the reproduction of putrefactive bacteria and significantly reducing the risk of secondary fermentation in open pits; relying on 2%-5% segmented micro-aerobic synergistic modification of diatomaceous earth enzymes, the straw fiber degradation efficiency is high and the fermentation acidification speed is fast; the fermentation bacteria are activated by a small amount of purified molasses waste liquid, resulting in good compatibility and low silage preparation cost; the entire process does not require dehydration to retain soluble nutrients, the finished product has high lactic acid content and excellent palatability, effectively improving the feed intake and digestibility of beef cattle, and the overall quality of the silage is excellent. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0013] Example 1: This Example 1 describes a low-cost straw-fermented beef cattle silage, prepared from the following raw materials in parts by weight: 100 parts of crushed crop straw (corn straw), 2.2 parts of compound crude enzyme (cellulase: xylanase = 1:1.5), 0.8 parts of molasses waste liquid for impurity removal, 0.5 parts of modified diatomaceous earth, and 0.35 parts of compound freeze-dried bacterial powder (Lactobacillus plantarum: Lactobacillus brunelli = 2.5:1). The preparation method of the molasses waste liquid is as follows: S1. Take the original industrial molasses waste liquid, put it into a low-temperature centrifuge, set the speed to 4500r / min and the centrifugation temperature to 6℃, and centrifuge at a constant temperature for 12min. S2. After centrifugation, the lower layer of colloids, bacteria, and high-salt precipitate is discarded. The upper clear liquid is collected, sealed, and kept for later use.

[0014] The preparation method of modified diatomaceous earth is as follows: S1. Soak natural diatomaceous earth in citric acid aqueous solution at room temperature for 2.5 hours to complete surface acidification modification. After modification, wash repeatedly with deionized water until the pH of the washing solution is 7. S2. Wash the diatomaceous earth and dry it in a 70℃ oven. Sieve and collect particles with a pore size of 10-20μm. Store the dried and sealed products for later use.

[0015] This embodiment describes a method for preparing low-cost fermented straw silage for beef cattle, with the following specific preparation steps: S1. Crush the corn stalks to 1-3cm and add water to adjust the overall moisture content of the material to 58%; S2. The compound crude enzyme and the molasses waste liquid were premixed to prepare a mixture. The mixture was sprayed onto the surface of the straw at 8% of the dry weight of the straw. After spraying, the mixture was stirred for 3 minutes. Then, modified diatomaceous earth was added and stirred for another 2 minutes to ensure that the enzyme solution and diatomaceous earth were evenly soaked and dispersed in the pores of the straw fibers. The mixture was then sent into a sealed pretreatment chamber, where the oxygen volume fraction was controlled at 2% and the temperature at 32°C. The mixture was then left to stand in a sealed chamber for 18 hours. S3. Close the air inlet valve of the chamber and let it stand for 6 hours until the oxygen in the chamber is completely depleted. S4. The material does not need to be dried or squeezed to dehydrate. It is directly and evenly sprinkled with compound freeze-dried bacterial powder, layered, packed, compacted and sealed in a pit, and anaerobic fermented for 10 days to finally produce low-cost straw fermented beef cattle silage.

[0016] Example 2: This Example 2 presents a low-cost straw-fermented beef cattle silage, prepared from the following raw materials in parts by weight: 100 parts of crushed crop straw (corn straw), 1.5 parts of compound crude enzyme (cellulase: xylanase = 1:1.5), 0.5 parts of molasses waste liquid for impurity removal, 0.3 parts of modified diatomaceous earth, and 0.2 parts of compound freeze-dried bacterial powder (Lactobacillus plantarum: Lactobacillus brunelli = 2.5:1). The preparation methods of the impurity-removed molasses waste liquid and modified diatomaceous earth in Example 2 are the same as those in Example 1; The preparation method of a low-cost straw fermented beef silage in Example 2 is the same as that in Example 1.

[0017] Example 3: This Example 3 describes a low-cost straw-fermented beef cattle silage, prepared from the following raw materials in parts by weight: 100 parts of crushed crop straw (corn straw), 3 parts of compound crude enzyme (cellulase: xylanase = 1:1.5), 1.2 parts of molasses waste liquid for impurity removal, 0.8 parts of modified diatomaceous earth, and 0.5 parts of compound freeze-dried bacterial powder (Lactobacillus plantarum: Lactobacillus brunelli = 2.5:1). The preparation methods of the impurity-removed molasses waste liquid and modified diatomaceous earth in Example 3 are the same as those in Example 1; The preparation method of a low-cost straw fermented beef silage in Example 3 is the same as that in Example 1.

[0018] Comparative Example 1: The feed for Comparative Example 1 was prepared from the following parts by weight of raw materials: 100 parts of crushed crop straw (corn straw), 2.2 parts of compound crude enzyme (cellulase: xylanase = 1:1.5), 0.8 parts of molasses waste liquid for impurity removal, 0.5 parts of modified diatomaceous earth, and 0.35 parts of compound freeze-dried bacterial powder (Lactobacillus plantarum: Lactobacillus brunelli = 2.5:1). The preparation methods of the impurity-removed molasses waste liquid and modified diatomaceous earth in Comparative Example 1 are the same as those in Example 1; The feed preparation method in Comparative Example 1 is the same as that in Example 1, except that in step S2, the feed is not sent to a closed pretreatment chamber, there is no airtightness or oxygen concentration control, and the material is in contact with the atmospheric environment throughout the process.

[0019] Comparative Example 2: The feed for Comparative Example 2 was prepared from the following parts by weight of raw materials: 100 parts of crushed crop straw (corn straw), 2.2 parts of compound crude enzyme (cellulase: xylanase = 1:1.5), 0.8 parts of molasses waste liquid for impurity removal, and 0.35 parts of compound freeze-dried bacterial powder (Lactobacillus plantarum: Lactobacillus brunelli = 2.5:1). The preparation methods of the impurity-removed molasses waste liquid and modified diatomaceous earth in Comparative Example 2 are the same as those in Example 1; The feed preparation method in Comparative Example 2 is the same as that in Example 1, except that modified diatomaceous earth is not added.

[0020] Performance testing 1. pH value and lactic acid content test Take 20g of silage samples from day 3 and day 5 of fermentation, crush them, add 180mL of deionized water, soak at room temperature for 30min with intermittent stirring, filter to obtain silage extract; use a pH meter to measure the pH value of the extract, and use high performance liquid chromatography to detect the lactic acid content in the extract, and record the pH and lactic acid values ​​of each group of samples.

[0021] Table 1. Test data of pH value and lactic acid content of each group of samples.

[0022] Examples 1-3 showed rapid acidification, with the pH dropping rapidly to around 4.0 within 5 days of fermentation, and the lactic acid accumulation was significantly higher than that of the two comparative groups. Comparative Example 1 lacked a closed micro-aerobic environment, resulting in inhibited lactic acid bacteria proliferation, low acid production, and a higher pH. Comparative Example 2 did not add modified diatomaceous earth, the composite crude enzyme was easily inactivated, there was insufficient fermentable substrate, and the lactic acid yield was low. This confirms that the closed micro-aerobic process of this invention, combined with modified diatomaceous earth, can promote lactic acid bacteria proliferation and rapidly complete silage acidification.

[0023] 2. Dry matter loss rate test Weigh the dry weight of the mixed straw material before fermentation and the dry weight of the silage product after fermentation and opening the pit. Set up 3 parallel samples for each group. Place the samples in an oven at 105℃ to dry to constant weight, cool and weigh them. Calculate the dry matter loss rate of each group according to the formula: Dry matter loss rate = (Total dry matter mass before fermentation - Total dry matter mass after fermentation) ÷ Total dry matter mass before fermentation × 100% and take the average value.

[0024] Table 2. Test data on dry matter loss rate of each group of samples

[0025] In the example group, the dry matter loss rate was controlled within 6%, and the material nutrient retention effect was good. In Comparative Example 1, the entire process was in contact with air, and a large amount of miscellaneous bacteria consumed organic matter, resulting in a significant increase in dry matter loss. In Comparative Example 2, the lack of modified diatomaceous earth protective enzyme activity led to a decrease in the stability of the fermentation system and an increase in organic matter loss. This indicates that the process of the present invention can retain straw nutrients to the greatest extent and reduce the loss of silage materials.

[0026] 3. Butyric acid content and yeast colony count tests Take 20g of the finished silage product, add 180mL of sterile deionized water for thorough extraction and filtration to obtain the extract. Part of the extract is extracted with organic phase and the butyric acid content is determined by high performance liquid chromatography. The other part of the extract is serially diluted, spread on potato dextrose agar medium, and incubated at constant temperature for 48h. The total number of yeast colonies in the sample is calculated. Each group is measured in parallel three times and the average value is taken.

[0027] Table 3. Test data of butyric acid content and yeast colony count for each group of samples.

[0028] Butyric acid is a hallmark product of silage spoilage, and yeast is the main mold-causing bacteria. In the example group, the butyric acid content was extremely low and the number of yeasts remained at a low level, demonstrating outstanding antibacterial and antiseptic effects. In contrast, in the aerobic environment of Comparative Example 1, a large number of spoilage bacteria and molds would proliferate, and butyric acid would be generated in large quantities, making the silage extremely prone to spoilage. In Comparative Example 2, the fermentation antibacterial ability was weak, and the number of miscellaneous bacteria increased significantly. This proves that the segmented micro-aerobic pretreatment combined with modified diatomaceous earth of this invention can effectively inhibit the reproduction of spoilage microorganisms and ensure the quality and safety of silage.

[0029] 4. Aerobic steady-state time test Take 500g of silage samples from each group after opening the silage pit and place them in an open sterile container. The ambient temperature is controlled at 25℃. The internal temperature of the sample is continuously monitored. When the sample temperature rises by 2℃ compared to the ambient temperature, it is determined that secondary fermentation has occurred. Record the time from when the sample is placed in the open until the temperature rises by more than 2℃, which is the aerobic stability time. Each group is tested in parallel three times and the average value is taken.

[0030] Table 4. Test data on aerobic stability time for each group of samples.

[0031] The silage in the example group had a much longer aerobic stability time than the two comparative groups, and had a strong resistance to secondary fermentation after opening the pit, making it suitable for long-term batch feeding in farms. Comparative group 1 had a high number of aerobic bacteria during the fermentation stage, and became moldy shortly after opening, showing extremely poor aerobic stability. Comparative group 2 had no adsorption and antibacterial effect of modified diatomaceous earth, and its ability to tolerate aerobic environments was insufficient. This verifies that the process of the present invention can significantly improve the stability of silage after opening the pit for feeding.

[0032] 5. Crude protein content test Take dried and pulverized silage samples to a 40-mesh sieve and conduct nitrogen determination using the Kjeldahl method, referring to the standard GB / T 6432-2018. Accurately weigh the sample and place it in a digestion tube. Add concentrated sulfuric acid and a mixed catalyst for high-temperature digestion. After cooling, add alkali and distill. Absorb ammonia with boric acid and titrate with hydrochloric acid standard solution. Calculate the crude protein content of the sample based on the volume of acid consumed in the titration. Perform three parallel tests for each group, and take the arithmetic mean of the final results.

[0033] Table 5. Crude protein content test data for each group of samples.

[0034] The crude protein content of each embodiment was increased after fermentation compared to the raw material. In Example 3, the enzyme addition was higher, resulting in the best protein enhancement effect. In Comparative Example 1, open fermentation led to protein decomposition and loss, resulting in a decrease in crude protein content. In Comparative Example 2, the protein preservation and enhancement effect was weak, indicating that the process of the present invention can effectively protect straw protein from degradation and improve the nutritional value of silage.

[0035] 6. Degradation rate of neutral detergent fiber (NDF) Corn stalk raw material before fermentation and silage product after fermentation were taken separately, crushed and passed through a 40-mesh sieve, and the neutral detergent fiber content of the two groups of samples was determined by the VanSoest washing fiber method according to GB / T 20806-2022 standard. The value was then calculated according to the formula NDF degradation rate = (NDF content before fermentation - NDF content after fermentation) ÷ NDF content before fermentation × 100%. Each group was tested in parallel three times and the average value was taken.

[0036] Table 6. NDF degradation rate test data for each group of samples

[0037] NDF is a fiber component in straw that is difficult to digest. The fiber degradation efficiency of the example group is excellent, which can destroy the coarse fiber structure of straw and improve the digestibility and absorption rate of livestock. In contrast, the aerobic environment of Comparative Example 1 causes the compound crude enzyme to be rapidly inactivated, and the degree of fiber degradation is extremely low. In Comparative Example 2, the lack of modified diatomaceous earth adsorption and protection enzymes leads to a significant decrease in enzymatic hydrolysis efficiency and a poorer effect on coarse fiber degradation. This proves that the formula and process of this invention can efficiently degrade straw coarse fiber and improve feed palatability and digestibility.

Claims

1. A low-cost straw-fermented silage for beef cattle, characterized in that, The feed is prepared from the following raw materials in parts by weight of straw dry matter: The ingredients are: 100 parts crushed crop straw, 1.5-3 parts compound crude enzyme, 0.5-1.2 parts impurity-removed molasses waste liquid, 0.3-0.8 parts modified diatomaceous earth, and 0.2-0.5 parts compound freeze-dried bacterial powder.

2. The low-cost straw-fermented beef cattle silage according to claim 1, characterized in that, The crop straw is selected from any one or more of corn straw, wheat straw, and rice straw.

3. The low-cost straw-fermented beef cattle silage according to claim 1, characterized in that, The composite crude enzyme is a mixture of cellulase and xylanase in a mass ratio of 1:1.2-1.8; the composite freeze-dried bacterial powder contains Lactobacillus plantarum and Lactobacillus buchneri in a mass ratio of 2:1-3:

1.

4. A method for preparing low-cost straw-fermented beef cattle silage according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Crush the crop straw to 1-3cm, and add water to adjust the material moisture content to 58%-62%; S2. Send the straw into a sealed pretreatment chamber, spray a mixture of compound crude enzyme and centrifuged molasses waste liquid, then add modified diatomaceous earth and mix thoroughly; control the oxygen volume fraction in the chamber to 2%-5% and the temperature to 32-38℃, and let it stand in a sealed chamber for 18-36 hours. S3. Close the air intake of the chamber and let it stand for 6-12 hours until the oxygen in the chamber is completely depleted; S4. The material does not need to be dehydrated. It is inoculated with compound freeze-dried bacterial powder under anaerobic environment, layered, compacted and sealed in pit, and anaerobic fermented for 10-20 days to produce beef cattle silage.

5. The method for preparing low-cost fermented straw silage for beef cattle according to claim 4, characterized in that, In step S2, the original molasses waste liquid is centrifuged before feeding to obtain the impurity-removed molasses waste liquid. The centrifugation process conditions are: centrifugation at 4000-5000 r / min speed and 4-10℃ low temperature for 10-15 min. The waste liquid after centrifugation is only used as a micronutrient activator for lactic acid bacteria.

6. The method for preparing low-cost fermented straw silage for beef cattle according to claim 4, characterized in that, In step S2, the mixed liquid is sprayed evenly onto the straw material at 8%-12% of the dry weight of the straw. After spraying, the mixture is stirred for 3-5 minutes. After adding the modified diatomaceous earth, the mixture is stirred for another 2 minutes to ensure that the enzyme solution and diatomaceous earth are evenly soaked and dispersed in the pores inside the straw fibers.

7. The method for preparing low-cost fermented straw silage for beef cattle according to claim 4, characterized in that, The entire preparation process requires no sun drying or squeezing to remove water, thus avoiding the loss of reducing sugars.

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