A processing method to improve the digestibility of rice husk nutrients for rabbits

Abstract

This invention relates to the field of animal husbandry technology, specifically a processing method for improving the digestibility of rice husk nutrients in rabbits. The method includes steps 1) micronizing rice husks to obtain rice husk powder; 2) acidifying the rice husk powder; and 3) puffing the material obtained in step 2). This method can alter the fiber composition of rice husk powder, reducing crude fiber content, especially lignin content, and increasing nitrogen-free extract content. It helps acidify the rabbit's intestines, increases intestinal nitrogen sources to promote bacterial protein synthesis, and improves the digestibility of rice husk powder nutrients in rabbits.

Description

Technical Field

[0001] This invention relates to the field of animal husbandry technology, specifically to a processing method for improving the digestibility of rice husk nutrients for rabbits. Background Technology

[0002] Southern my country is a major production and consumption area for meat rabbits. However, due to the relative scarcity of forage resources in the south, especially high-quality alfalfa hay, a large amount of hay needs to be imported from the north every year. Long-distance transportation keeps forage prices high. Furthermore, if the hay is exposed to rain during the drying process, it is very susceptible to mold, leading to excessive levels of mycotoxins. The transportation costs of purchased hay and the risk of mold damage severely restrict the improvement of the economic benefits of meat rabbit farming in the south.

[0003] Southern China is a major rice-producing region, and rice processing generates a large amount of rice husk byproducts. Rice husks, as a rice byproduct, have advantages such as high yield, concentrated production, low mold content, and low price, making them an important alternative to alfalfa for rabbit feed companies in the south. However, rice husk powder contains 43.34% crude fiber, 70.25% neutral detergent fiber, 60.54% acid detergent fiber, and 13.40% lignin, with a high lignin content. Studies have found that the processing technology of rice husks and lignin content are the main reasons for the low utilization of nutrients from rice husks by rabbits. How to improve the production and processing technology of rice husk powder, reduce its lignin content, and thus improve its nutrient digestibility has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the current technology by providing a processing method that improves the digestibility of rice husk nutrients for rabbits. This method can significantly reduce the content of fiber components, especially lignin content, significantly improve the fiber composition of rice husk powder, reduce lignin content, and increase the digestibility of rice husk powder for rabbits.

[0005] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0006] A processing method for improving the digestibility of rice husk nutrients for rabbits includes the following steps:

[0007] 1) Finely pulverize the rice husks;

[0008] 2) The rice husks crushed in step 1) are subjected to acidification treatment;

[0009] 3) The rice husks that have undergone acidification in step 2) are then puffed.

[0010] As a preferred embodiment of this application, in the processing method for improving the digestibility of rice husk nutrients for rabbits, the pulverizing device used in step 1) for micro-pulverization is a vertical mechanical impact pulverizer.

[0011] As a preferred embodiment of this application, in the processing method for improving the digestibility of rice husk nutrients for rabbits, the particle size after micro-pulverization in step 1) is sieved through a 50-mesh sieve.

[0012] As a preferred embodiment of this application, in the processing method for improving the digestibility of rice husk nutrients for rabbits, the specific steps of acidification treatment in step 2) are as follows: first, formic acid is added to the rice husk powder obtained in step 1) and mixed; then, cellulase is added to it and mixed.

[0013] In a preferred embodiment of this application, the amount of formic acid added is 2% of the mass of rice husk powder, and the mixing time after adding formic acid is 2 hours; the amount of cellulase (acid-resistant, enzyme activity >= 7000 U / g) added is 0.05% of the mass of rice husk powder, and the mixing time after adding cellulase is 46 hours.

[0014] As a preferred embodiment of this application, in the processing method for improving the digestibility of rice husk nutrients for rabbits, the puffing treatment in step 3) is a single-screw dry extrusion puffing process.

[0015] As a preferred embodiment of this application, in the processing method for improving the digestibility of rice husk nutrients for rabbits, ammonium bicarbonate must be added and mixed evenly before puffing; preferably, the amount of ammonium bicarbonate added is 1% of the mass of rice husk powder.

[0016] As a preferred embodiment of this application, in the processing method for improving the digestibility of rice husk nutrients for rabbits, the conditions for the puffing treatment in step 3) are as follows: the rotation speed of the cutting part is 500 r / min, the puffing temperature is 160-180℃, the puffing pressure is 3.5-4.5 MPa, the extrusion time is 3-5 s, and the mold opening is 2 mm.

[0017] Another objective of this application is to protect rice husks obtained by any of the processing methods or combinations thereof described above.

[0018] Furthermore, the fiber content in rice husks obtained using the above methods is significantly reduced, especially the lignin content, which significantly improves the fiber composition of rice husk powder and increases the nutritional value of rice husks.

[0019] The third objective of this application is to protect the application of rice husks obtained by the above method, wherein the rice husks are used to improve the digestibility of rabbits.

[0020] Compared with existing technologies, the beneficial effects of this invention are:

[0021] (I) This method is simple and easy to implement, and can significantly optimize the content of fiber components in rice husks, especially significantly reducing the lignin content and increasing the content of nitrogen-free extracts, significantly changing the fiber composition of rice husk powder and optimizing and improving the nutrients in rice husks.

[0022] (ii) This method helps to deacidify the intestines. It utilizes the acidification effect of formic acid on rice husk powder, as well as the silicon dioxide and calcium ions in rice husks, to generate calcium formate after the reaction. Calcium formate can act as an acidifier, which helps to acidify the intestines and digest and absorb nutrients.

[0023] (III) This method cleverly utilizes ammonium bicarbonate, which changes the traditional use of sodium carbonate in puffing. Formic acid is used to make carbonate ions more easily decompose into carbon dioxide, greatly reducing the amount of carbonate used. It also utilizes high temperature and formic acid to generate some urea, which can be used as a nitrogen source to provide nitrogen for the fermentation of bacterial protein in the cecum of rabbits.

[0024] (iv) The rice husks obtained by this method have increased nutrients, which can be better used to improve the digestibility of rabbits. Detailed Implementation

[0025] A processing method for improving the digestibility of rice husk nutrients for rabbits includes the following steps:

[0026] 1) The rice husks are micro-pulverized to obtain rice husk powder; preferably, a vertical mechanical impact pulverizer is used for micro-pulverization, and the pulverized particle size passes through a 50-80 mesh sieve; more preferably, it passes through a 50 mesh sieve.

[0027] 2) Acidify the rice husk powder from step 1);

[0028] The specific steps of the acidification treatment are as follows: First, formic acid is added to the rice husk powder obtained in step 1) and mixed; then, cellulase is added and mixed. The amount of formic acid added is 2% of the mass of the rice husk powder, and the mixing time after adding formic acid is 2 hours; the amount of cellulase (acid-resistant, enzyme activity >= 7000 U / g) added is 0.05% of the mass of the rice husk powder, and the mixing time after adding cellulase is 46 hours.

[0029] 3) The rice husk powder processed in step 2) is puffed.

[0030] The puffing process adopts a single-screw dry extrusion puffing process. Before puffing, ammonium bicarbonate must be added to the rice husk powder after step 2) and mixed evenly for puffing. The amount of ammonium bicarbonate added is 2% of the mass of the rice husk powder in step 1). The puffing process parameters are: cutting speed of 500 r / min, puffing temperature of 160-180℃ and pressure of 3.5-4.5 MPa, extrusion time of 3-5 s, and die opening of 2 mm.

[0031] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0032] Any feature disclosed in this specification (including the claims and abstract) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0033] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0034] Example 1:

[0035] A processing method for improving the digestibility of rice husk nutrients for rabbits includes the following steps:

[0036] 1) The rice husks are finely pulverized using a vertical mechanical impact pulverizer, and the pulverized particle size is 50 mesh.

[0037] 2) Acidify the rice husk powder from step 1); that is, first add 2% (by weight of rice husk powder) of formic acid to the rice husk powder obtained in step 1) and mix for 2 hours; then add 0.05% (by weight of rice husk powder) of cellulase (which is acid-resistant and has an enzyme activity of 7000 U / g) and mix and acidify for 46 hours.

[0038] 3) The rice husk powder processed in step 2) is then subjected to puffing. The puffing process adopts a single-screw dry extrusion puffing process (existing technology, not described in detail); before puffing, 2% (based on the rice husk powder in step 1) of ammonium bicarbonate is added and mixed evenly before puffing; the puffing process parameters are: cutting section rotation speed of 500 r / min, puffing temperature of 160-180℃, puffing pressure of 3.5-4.5 MPa, extrusion time of 3-5 s, and die opening of 2 mm.

[0039] Experiment 1:

[0040] An optimization experiment was conducted on the micro-pulverization method in the processing method for improving the digestibility of rice husk nutrients for rabbits in Example 1:

[0041] Three pulverizing methods were selected for the experiment: Group A (ball mill), Group B (hammer mill), and Group C (vertical mechanical impact pulverizer used in this invention). The rice husk powder was sieved through 30-mesh, 40-mesh, 50-mesh, 60-mesh, 70-mesh, and 80-mesh screens, respectively. The sieved rice husk powder was then subjected to a digestibility test according to the Rabbit Feed Digestibility Test Procedure (T / CAAA026-2019) to determine the dry matter digestibility of the rice husk powder.

[0042] Table 1. Effects of different grinders and particle sizes on rabbit digestibility.

[0043]

[0044] Note: Uppercase letters indicate comparisons of data in the same column, lowercase letters indicate comparisons of data in the same row, the same letters indicate no significant difference, different letters indicate significant difference (P < 0.05).

[0045] The experimental results showed that in Group C, the rice husks were pulverized into hexagonal polygonal particles with low starch content, uniform size, good flowability, and easier digestibility. Under the same particle size, the digestibility of rice husk powder in Group C was significantly higher than that in Groups A and B. At different particle sizes, the digestibility of rice husks significantly increased with decreasing particle size, but there was no significant difference between 50 mesh and 60 mesh. The experiment indicated that Group C had the highest dry matter digestibility at the 50 mesh size.

[0046] Experiment 2:

[0047] An optimization experiment was conducted on the puffing treatment in the processing method for improving the digestibility of rice husk nutrients for rabbits in Example 1.

[0048] 1. Three single-screw dry extrusion processes were selected for the experiment. In Group A, the cutting speed was 400 r / min, the extrusion temperature was 140–160℃, and the pressure was 2.5–3.5 MPa; in Group B, the cutting speed was 500 r / min, the extrusion temperature was 160–180℃, and the pressure was 3.5–4.5 MPa; and in Group C, the cutting speed was 600 r / min, the extrusion temperature was 180–200℃, and the pressure was 4.5–5.5 MPa. The extrusion time for all groups was uniformly 3–5 seconds, and the die opening was uniformly 2 mm. The rice husk powder used in the experiment was rice husk powder pulverized through a vertical mechanical impact pulverizer to a mesh size of 50. The dry matter digestibility of the extruded rice husk powder was determined according to the method of the Rabbit Feed Digestibility Test Procedure (T / CAAA026-2019).

[0049] Table 2. Effects of different puffing processes on the digestibility of rice husks in rabbits.

[0050] Group Experimental Group A Experimental Group B Experimental Group C Dry matter digestibility <![CDATA[32.8% a ]]> <![CDATA[38.2% c ]]> <![CDATA[35.8% b ]]>

[0051] Note: Lowercase letters indicate comparisons of data from the same row. The same letters indicate no significant difference, while different letters indicate a significant difference (P < 0.05). Tables 2, 3, 4 and 5 are the same.

[0052] The experimental results show that in Group B, the cutting speed was 500 r / min, the puffing temperature was 160-180℃ and the pressure was 3.5-4.5 MPa; the extrusion time was uniformly 3-5 s and the mold opening was uniformly 2 mm. This process group had the highest dry matter digestibility after puffing rice husk powder.

[0053] 2. Three single-screw dry extrusion processes were selected for the experiment. Group A had an extrusion time of 2–4 seconds and a die opening of 1 mm; Group B had an extrusion time of 3–5 seconds and a die opening of 2 mm; Group C involved cutting, with an extrusion time of 4–6 seconds and a die opening of 3 mm. The cutting section rotation speed was 500 r / min for all groups, and the extrusion temperature was 160–180℃, while the pressure was 3.5–4.5 MPa. The rice husk powder used in the experiment was pulverized using a vertical mechanical impact mill and passed through a 50-mesh screen. The dry matter digestibility of the extruded rice husk powder was determined according to the Rabbit Feed Digestibility Test Procedure (T / CAAA026-2019).

[0054] Table 3. Effects of different puffing processes on the digestibility of rice husks in rabbits.

[0055] Group Experimental Group A Experimental Group B Experimental Group C Dry matter digestibility <![CDATA[35.3% a ]]> <![CDATA[38.3% c ]]> <![CDATA[34.3% a ]]>

[0056] The experimental results show that in Group B, the cutting speed was 500 r / min, the puffing temperature was 160-180℃ and the pressure was 3.5-4.5 MPa; the extrusion time was uniformly 3-5 s and the mold opening was uniformly 2 mm. This process group had the highest dry matter digestibility after puffing rice husk powder.

[0057] Experiment 3:

[0058] To further improve the puffing effect of rice husks, acidification experiments were conducted. Experiment A used rice husk powder passed through a vertical mechanical impact pulverizer to a mesh size of 50, without the addition of an acidifier; Experiment B used rice husk powder passed through a vertical mechanical impact pulverizer to a mesh size of 50, with the addition of 1% formic acid, and acidified for 24 hours; Experiment C used rice husk powder passed through a vertical mechanical impact pulverizer to a mesh size of 50, with the addition of 2% formic acid, and acidified for 48 hours; Experiment D used rice husk powder passed through a vertical mechanical impact pulverizer to a mesh size of 50, with the addition of 2% formic acid, acidified for 48 hours, and then 0.05% cellulase was added after 2 hours of acidification. All experimental groups used a puffing process with a cutting speed of 500 r / min, a puffing temperature of 160–180℃, and a pressure of 3.5–4.5 MPa; the extrusion time was uniformly 3–5 seconds, and the die opening was uniformly 2 mm. The dry matter digestibility of puffed rice husk powder was determined by means of the method described in the Rabbit Feed Digestion Test Procedure (T / CAAA026-2019).

[0059] Table 4. Effects of different doses of acidifying agent and acidification time on the digestibility of puffed rice husks in rabbits.

[0060] Group Experimental Group A Experimental Group B Experimental Group C Experimental Group D Dry matter digestibility <![CDATA[38.2% a ]]> <![CDATA[40.5% b ]]> <![CDATA[42.1% c ]]> <![CDATA[43.8% d ]]>

[0061] The experimental results showed that in Group D, the rice husk powder with 2% formic acid added and acidified for 48 hours, and then with 0.05% cellulase added 2 hours after acidification, had the highest dry matter digestibility after puffing.

[0062] Further experiments compared the effects of adding ammonium bicarbonate and sodium carbonate during the puffing process on the fiber composition of rice husks. Each experimental group used a vertical mechanical impact pulverizer to process rice husk powder through a 50-mesh screen. 2% formic acid was added, followed by 2 hours of acidification, then 0.05% cellulase, and a further 46 hours of acidification. The puffing process was maintained at a cutting speed of 500 r / min, a puffing temperature of 160–180℃, and a pressure of 3.5–4.5 MPa. The extrusion time was uniformly 3–5 seconds, and the die opening was uniformly 2 mm. Experiment A did not add ammonium bicarbonate, Experiment B added 1% ammonium bicarbonate, Experiment C added 2% ammonium bicarbonate, Experiment D added 4% sodium carbonate, and Experiment E added 6% sodium carbonate. The dry matter digestibility of the puffed rice husk powder was determined according to the Rabbit Feed Digestion Test Procedure (T / CAAA026-2019); the fiber composition of the puffed rice husks was determined using the Van der Waals method. The percentages represent the mass percentage, and the amount of calcium formate added is based on the mass of the crushed rice husk powder.

[0063] Table 5. Effects of different swelling aids on rabbit digestibility of puffed rice husk.

[0064] Group Experimental Group A Experimental Group B Experimental Group C Experimental Group D Experimental Group E Dry matter digestibility <![CDATA[43.7% a ]]> <![CDATA[48.5% d ]]> <![CDATA[47.3% c ]]> <![CDATA[45.8% b ]]> <![CDATA[46.2% b ]]>

[0065] The experimental results showed that adding 1% ammonium bicarbonate to rice husk powder after pulverization and acidification significantly affected the digestibility of puffed rice husk powder, with the dry matter digestibility reaching 48.5%.

[0066] Table 6. Effects of different puffing process combinations on the digestibility of rice husks in rabbits.

[0067] Group crude fiber Nitrogen-free extract Neutral detergent fibers Acid detergent fibers Acid lignin Experimental Group A <![CDATA[40.34% a ]]> <![CDATA[27.88% a ]]> 70.25％ <![CDATA[60.54% a ]]> <![CDATA[12.40% a ]]> Experimental Group B <![CDATA[32.12% c ]]> <![CDATA[36.12% c ]]> 69.05％ <![CDATA[50.26% c ]]> <![CDATA[7.36% c ]]> Experimental Group C <![CDATA[33.26% c ]]> <![CDATA[34.96% c ]]> 69.28％ <![CDATA[51.24% c ]]> <![CDATA[7.45% c ]]> Experimental Group D <![CDATA[37.25% b ]]> <![CDATA[30.97% b ]]> 70.12％ <![CDATA[55.5% b ]]> <![CDATA[10.02% b ]]> Experimental Group E <![CDATA[36.55% b ]]> <![CDATA[31.67% b ]]> 70.12％ <![CDATA[55.5% b ]]> <![CDATA[9.82% b ]]>

[0068] Note: Lowercase letters indicate comparisons of data in the same column. The same letters or no letters indicate no significant difference, while different letters indicate a significant difference (P < 0.05).

[0069] The experimental results showed that the subsequent addition of 1% ammonium bicarbonate to rice husk powder had a significant effect on the changes in the fiber composition of puffed rice husk powder. Crude fiber, acid detergent fiber, and acid lignin decreased significantly, while neutral detergent fiber showed no significant change, and nitrogen-free extract increased. This indicates that the digestible hemicellulose (a heteropolysaccharide composed of glucose, fructose, xylose, mannose, and arabinose) in rice husk powder increased significantly, and the digestibility of rice husks increased significantly.

[0070] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0071] This background section is provided to generally present the context of the invention. The work of the currently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither expressly nor impliedly acknowledged as prior art to the invention.

Claims

1. A processing method for improving the digestibility of rice husk nutrients for rabbits, characterized in that... Includes the following steps: 1) The rice husks are finely pulverized to a particle size that passes through a 50-mesh sieve to obtain rice husk powder; 2) The rice husks crushed in step 1) are subjected to acidification treatment. The acidification treatment involves first adding formic acid and mixing, and then adding cellulase and mixing. The amount of formic acid added is 2% of the mass of the rice husk powder, and the mixing time after adding formic acid is 2 hours. The amount of cellulase added is 0.05% of the mass of the rice husk powder, and the mixing time after adding cellulase is 46 hours. 3) The rice husks after acidification in step 2) are puffed. Ammonium bicarbonate must be added and mixed evenly before puffing. The conditions for puffing are: the rotation speed of the cutting part is 500 r / min, the puffing temperature is 160-180℃, the puffing pressure is 3.5-4.5 MPa, the extrusion time is 3-5 s, and the mold opening is 2 mm.

2. The processing method for improving the digestibility of rice husk nutrients for rabbits according to claim 1, characterized in that, The pulverizing device used in step 1) is a vertical mechanical impact pulverizer.

3. The processing method for improving the digestibility of rice husk nutrients for rabbits according to claim 1, characterized in that, The puffing process described in step 3) is a single-screw dry extrusion puffing process; the amount of ammonium bicarbonate added is 1% of the mass of rice husk powder.

4. The processing method for improving the digestibility of rice husk nutrients for rabbits according to claim 1, characterized in that, Cellulase is acid-resistant, with an enzyme activity of >=7000 U / g.

5. Rice husks obtained by any of the processing methods described in claims 1-4.

6. The application of rice husk according to claim 5, characterized in that, The rice husks are used to improve the digestibility of rabbit feed.

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