Method for reducing mycotoxin content in corn undersize and preparing feed

Abstract

The present invention provides a method for reducing the mycotoxin content in functional corn undercuts, wherein the mycotoxin content in the corn undercuts can be significantly reduced by synergistically fermenting the corn undercuts with composite bacteria, enzyme preparations and inorganic salts. At the same time, the present invention also relates to the use of the corn undercut fermentation product obtained by the above method in preparing feed and a method for preparing corn undercut fermented feed. By reducing the mycotoxin content in the corn undercuts, the economic value of the corn undercuts is increased, which helps to improve the economic benefits of grain trade and increases the storage period and value of the corn overcuts.

Description

Technical Field

[0001] The present invention belongs to the field of deep processing of corn by-products, and specifically relates to a method for reducing the mycotoxin content in corn undercuts, use of corn undercut fermentation products with reduced toxin content in preparing feed, and a method for preparing corn undercut fermented feed. Background Art

[0002] In recent years, despite the continuous increase in global feed production, the shortage of feed resources has gradually become a bottleneck for the development of the world's feed industry. Therefore, on the one hand, feed raw materials are in short supply, and about 40% of the grain produced by cultivated land is used to produce feed. There are problems such as competition between people and animals for food, and we have to rely heavily on imports. The feed cost fluctuates significantly, which has become a bottleneck that has long restricted the development of my country's animal husbandry; on the other hand, due to the limitations of the existing feed processing and consumption methods, such as short time, low moisture, high energy consumption, and long shelf life, the room for improving the nutritional value of traditional feed is very limited; at the same time, a considerable amount of cheap food by-product resources are discarded in large quantities because they cannot be fully utilized by animals, resulting in resource waste and environmental pollution. It can be seen that the gap between feed supply and demand based on feed cost and nutritional value is still relatively large. It is currently believed that the development of bio-fermented feed can help alleviate the problem of scarce feed resources.

[0003] Moreover, the concepts of food safety and feed safety have reached new heights both worldwide and domestically, and the production of antibiotic-free feed has become a trend in the animal husbandry industry. As a highly efficient, pollution-free, and residue-free natural health-care feed additive, biological feed has a variety of biological functions, including improving the palatability of feed, promoting the growth and development of pigs, increasing the digestibility and utilization of nutrients in feed, preventing digestive tract diseases, enhancing animal immunity, and reducing breeding costs. With the popularization of the application scope of fermented feed, it is urgent to master the laws of the effects of fermented concentrated feed on growth and fattening, and to create and use safe, efficient, environmentally friendly, and antibiotic-free diets.

[0004] Corn is one of the major grain trade products, and it has an irreplaceable position in feed, food, chemical industry and other fields. Generally speaking, corn in the three northeastern provinces of my country will go through the drying process after harvest to reduce its moisture content, so that the corn is not easy to mold and is easy to store. The moisture content of corn is usually around 30% at harvest, and the moisture content after drying is only 14%. During the entire screening process, corn is screened into oversize and undersize. Due to excessive mycotoxin content, the market value of by-products such as corn undersize cannot be best reflected when they are sold or processed separately.

[0005] At present, the methods for processing high-moisture corn undercuts in the industry include drying, screening, acidification, etc. How to select the method with the highest input-output ratio from a more economical perspective requires consideration of the following aspects: (1) storability, the storage period must be at least 6 months; (2) mold problem, methods that can improve storage stability, with no mold as the best; (3) economy, processing under the premise of minimizing costs; (4) trying not to change the original business model to avoid cost increases. After considering the above factors, the inventors of the present invention noticed that fermenting corn undercuts to produce biological feed may be a feasible method. From a biological point of view, the essence of fermentation is the intervention of microorganisms, which is a method that can improve the properties of fermentation raw materials. However, if it is intended to be used for the preparation of feed, the main focus of corn undercuts is on the control of mycotoxins. From the storage of grain, feed raw materials to finished feed products, mycotoxin contamination is inevitable. How to achieve effective biodegradation of mycotoxins in corn undercuts will be a key issue in improving the application of corn undercuts in the feed field. Summary of the invention

[0006] To solve the above problems, the inventors have explored a method to reduce the mycotoxin content in functional corn undercuts by integrating the by-product resources of grain and oil processing and using the technical means of synergistic fermentation of composite bacteria, enzyme preparations and inorganic salts, thereby enabling the efficient use of corn undercuts to produce biological feed.

[0007] In a first aspect of the present invention, the present invention provides a method for reducing the mycotoxin content in corn undersize, comprising: adding a composite bacterial strain, an enzyme preparation and an inorganic salt to a fermentation raw material to obtain a material to be fermented and fermenting the material;

[0008] The composite bacteria include Lactobacillus plantarum, Candida utilis and Bacillus subtilis; the enzyme preparation includes papain; the inorganic salt includes ammonium salt, potassium salt, and at least one selected from manganese salt and magnesium salt; and the fermentation raw material includes corn screenings.

[0009] In a second aspect, the present invention provides use of the corn undersize fermentation product obtained by the above method in preparing feed.

[0010] In a third aspect, the present invention provides a method for preparing corn undersize fermented feed, comprising:

[0011] (1) mixing corn undersize, enzyme preparation and inorganic salt with one or more selected from corn, soybean meal, soybean hull, bran, rapeseed meal, distiller's grains, sugar residue and molasses, wherein the enzyme preparation includes papain, and the inorganic salt includes ammonium salt, potassium salt and at least one selected from manganese salt and magnesium salt;

[0012] (2) inoculating the mixture obtained in step (1) with a composite bacterial strain to obtain a material to be fermented, wherein the composite bacterial strain includes Lactobacillus plantarum, Candida utilis and Bacillus subtilis;

[0013] (3) Fermenting the material to be fermented, and drying, cooling, and crushing the fermentation product to obtain the corn undersize fermented feed.

[0014] The method of the present invention can achieve significant economic benefits. With an annual trade volume of 20 million tons of corn, only corn screenings amount to 100,000 tons. In addition, in China's feed industry today, corn accounts for more than 50% of feed raw materials. If the corn screenings (corn kernel content is about 70%) are sold directly to the outside, the price per ton is only about 500 yuan. If the composite strain can be used to produce feed by microbial fermentation, the price per ton of feed can reach about 2,000 yuan, and the overall profit will be very considerable. In addition, due to the reduction of mycotoxin content, the storage period and value enhancement advantages of corn screenings are also very obvious. DETAILED DESCRIPTION

[0015] Next, exemplary embodiments of the present invention are described, but the protective scope of the present invention is not limited thereto.

[0016] Corn undersize refers to the material obtained by screening corn before and after drying in order to better ensure the preservation quality of corn before corn storage units are put into storage. High-moisture corn is first screened before drying, and the full kernels obtained after removing the undersize continue to be dried. The full kernels are screened for the second time after drying, and the corn broken kernels produced by drying can be stored in the warehouse after removing them. Therefore, a large amount of corn undersize can be produced during the corn drying process. Corn undersize includes broken corn kernels, shriveled kernels, bran, whiskers, core fragments, etc., of which the corn content is about 70wt%. Corn undersize contains rich nutrients such as crude starch and crude protein, which can provide energy and protein nutrition for animal feeding, and can also provide carbon and nitrogen sources for probiotic fermentation. However, since the mycotoxin content of corn undersize exceeds the standard, it cannot be directly used, resulting in a waste of resources.

[0017] Taking corn undercuts produced during corn processing as an example, an assessment of its nutritional content and mycotoxins was conducted. It was determined that the moisture content of the corn undercuts was 12.51wt%, the crude protein content was 8.81wt%, the crude fat content was 0.57wt%, the crude fiber content was 6.76wt%, the crude ash content was 2.53wt%, the crude starch content was 55.13wt%, and the reducing sugar content was 1.35wt%; among the hazard indicators, the aflatoxin B1 content was 15.9ppb, the vomitoxin content was 635.15ppb, and the zearalenone content was 3680ppb; compared with the aflatoxin limit standards for corn in my country's grain and food (aflatoxin B1 content is ≤20ppb, vomitoxin content is ≤500ppb, and zearalenone content is ≤1000ppb), the contents of the above three toxins in the corn undercuts exceeded the standards, among which the zearalenone content exceeded the standards seriously, thus seriously limiting the resource utilization value of the corn undercuts in the grain and food fields. At the same time, compared with the mycotoxin content limit values ​​for feed raw materials specified in the national standard "GB 13078-2017 Feed Hygiene Standard" (aflatoxin B1 ≤ 50 ppb, zearalenone (ZEN) ≤ ​​500 ppb, vomitoxin (DON) ≤ 5000 ppb), the zearalenone content in feed is also seriously exceeded, which also restricts its direct application as a feed raw material.

[0018] Therefore, it is necessary to reduce the toxin content by processing corn screenings, thereby increasing the economic value of corn screenings and maximizing resource utilization.

[0019] In view of the above situation, the present invention has developed a method for degrading mycotoxins in functional corn undercuts, thereby making full use of the corn undercuts to achieve better economic value and industrial value.

[0020] In one embodiment, the present invention provides a method for reducing the mycotoxin content in corn undersize, comprising: adding a composite bacterial strain, an enzyme preparation and an inorganic salt to a fermentation raw material to obtain a material to be fermented and fermenting the material;

[0021] The fermentation raw material comprises corn undersize, the composite bacteria comprises Lactobacillus plantarum, Candida utilis and Bacillus subtilis, the enzyme preparation comprises papain, and the inorganic salt comprises ammonium salt, potassium salt, and at least one selected from manganese salt and magnesium salt.

[0022] Alternatively, the present invention relates to use of a combination of a composite bacterial strain, an enzyme preparation and an inorganic salt in reducing the mycotoxin content in corn screenings.

[0023] In some embodiments, the fermentation feedstock comprises corn screenings and glucose.

[0024] In some preferred embodiments, the water content of the fermentation raw material is 20wt%-60wt%, for example, 30wt%-45wt%.

[0025] In some preferred embodiments, before adding the composite bacteria, enzyme preparation and inorganic salt, the pH of the fermentation raw material is adjusted to 5.0-7.0, preferably 5.5-6.5 (eg 6.0).

[0026] In some embodiments, the fermentation feedstock comprises: corn undersize; and one or more selected from the group consisting of corn, soybean meal, soybean hulls, bran, rapeseed meal, distiller's grains, sugar residue, and molasses.

[0027] In some embodiments, the content of the corn undersize is 10 wt%-90 wt% (eg, 20 wt%-80 wt%, 20 wt%-70 wt%) relative to the total mass of the material to be fermented.

[0028] In some embodiments, the composite bacteria is composed of Lactobacillus plantarum 1.557 (CGMCC), Candida utilis 2.1180 (CGMCC) and Bacillus subtilis 1.1413 (CGMCC). In some preferred embodiments, the bacterial count ratio of Lactobacillus plantarum 1.557 (CGMCC), Candida utilis 2.1180 (CGMCC) and Bacillus subtilis 1.1413 (CGMCC) is (40-50):(10-70):(0.5-4), for example 45:(20-60):(2-3).

[0029] In some embodiments, the inoculation amount of the composite bacteria (in terms of volume to mass ratio) is 0.5%-10%, preferably 2%-5%.

[0030] In this article, the inorganic salt is preferably a water-soluble inorganic salt, so as to be more conducive to the fermentation. In some embodiments, the inorganic salt includes ammonium salt, potassium salt and manganese salt, or includes ammonium salt, potassium salt and magnesium salt. Preferably, the inorganic salt includes ammonium salt, potassium salt and manganese salt in a mass ratio of 2:2:1, or includes ammonium salt, potassium salt and magnesium salt in a mass ratio of 2:2:1. Wherein, when the inorganic salt includes manganese salt, a relatively better fermentation degradation effect can be achieved.

[0031] In some preferred embodiments, the ammonium salt is one or more selected from the following: ammonium chloride, ammonium sulfate, ammonium hydrogen sulfate, ammonium nitrate, ammonium carbonate. In some preferred embodiments, the potassium salt is one or more selected from the following: potassium sulfate, potassium chloride, potassium nitrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium phosphate. In some preferred embodiments, the manganese salt is one or more selected from the following: manganese acetate, manganese sulfate, manganese chloride, manganese nitrate. In some preferred embodiments, the magnesium salt is one or more selected from the following: magnesium sulfate, magnesium chloride, magnesium nitrate. In some more preferred embodiments, the inorganic salt includes ammonium sulfate, potassium dihydrogen phosphate and manganese sulfate; or includes ammonium sulfate, potassium dihydrogen phosphate and magnesium sulfate.

[0032] In some embodiments, the amount of the inorganic salt added is 0.3 wt%-1.0 wt%, for example 0.5 wt%, relative to the total mass of the material to be fermented.

[0033] In some embodiments, the amount of the enzyme preparation added is 0.3 wt%-1.0 wt%, for example 0.5 wt%, relative to the total mass of the material to be fermented.

[0034] In some embodiments, the fermentation is performed at 20°C to 50°C (eg, 25°C to 40°C) for 1-10 days (eg, 2-6 days).

[0035] In one embodiment, the present invention provides use of the corn undersize fermentation product obtained by the above method in preparing feed.

[0036] In one embodiment, the present invention provides a method for preparing corn undersize fermented feed, comprising:

[0037] (1) mixing corn undersize, enzyme preparation and inorganic salt with one or more selected from corn, soybean meal, soybean hull, bran, rapeseed meal, distiller's grains, sugar residue and molasses, wherein the enzyme preparation includes papain, and the inorganic salt includes ammonium salt, potassium salt and at least one selected from manganese salt and magnesium salt;

[0038] (2) inoculating the mixture obtained in step (1) with a composite bacterial strain to obtain a material to be fermented, wherein the composite bacterial strain includes Lactobacillus plantarum, Candida utilis and Bacillus subtilis;

[0039] (3) Fermenting the material to be fermented, and drying, cooling, and crushing the fermentation product to obtain the corn undersize fermented feed.

[0040] In some embodiments, the inorganic salt comprises an ammonium salt, a potassium salt and a manganese salt, or comprises an ammonium salt, a potassium salt and a magnesium salt. Preferably, the inorganic salt comprises an ammonium salt, a potassium salt and a manganese salt in a mass ratio of 2:2:1, or comprises an ammonium salt, a potassium salt and a magnesium salt in a mass ratio of 2:2:1.

[0041] In some preferred embodiments, the ammonium salt is one or more selected from the following: ammonium chloride, ammonium sulfate, ammonium hydrogen sulfate, ammonium nitrate, ammonium carbonate. In some preferred embodiments, the potassium salt is one or more selected from the following: potassium sulfate, potassium chloride, potassium nitrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium phosphate. In some preferred embodiments, the manganese salt is one or more selected from the following: manganese acetate, manganese sulfate, manganese chloride, manganese nitrate. In some preferred embodiments, the magnesium salt is one or more selected from the following: magnesium sulfate, magnesium chloride, magnesium nitrate. In some more preferred embodiments, the inorganic salt includes ammonium sulfate, potassium dihydrogen phosphate and manganese sulfate; or includes ammonium sulfate, potassium dihydrogen phosphate and magnesium sulfate.

[0042] In some embodiments, the amount of the inorganic salt added is 0.3 wt%-1.0 wt%, for example 0.5 wt%, relative to the total mass of the material to be fermented.

[0043] In some embodiments, the amount of the enzyme preparation added is 0.3 wt%-1.0 wt%, for example 0.5 wt%, relative to the total mass of the material to be fermented.

[0044] In some embodiments, the content of the corn undersize is 10 wt%-90 wt% (eg, 20 wt%-80 wt%, 20 wt%-70 wt%) relative to the total mass of the material to be fermented.

[0045] In some embodiments, the composite bacteria is composed of Lactobacillus plantarum 1.557 (CGMCC), Candida utilis 2.1180 (CGMCC) and Bacillus subtilis 1.1413 (CGMCC). In some preferred embodiments, the bacterial count ratio of Lactobacillus plantarum 1.557 (CGMCC), Candida utilis 2.1180 (CGMCC) and Bacillus subtilis 1.1413 (CGMCC) is (40-50):(10-70):(0.5-4), for example 45:(20-60):(2-3).

[0046] In some embodiments, the inoculation amount of the composite bacteria (in terms of volume to mass ratio) is 0.5%-10%, preferably 2%-5%.

[0047] In some embodiments, the fermentation is performed at 20°C to 50°C (eg, 25°C to 40°C) for 1-10 days (eg, 2-6 days).

[0048] Exemplary embodiments of the present invention are described in the following numbered paragraphs:

[0049] 1. A method for reducing the mycotoxin content in corn undersize, comprising: adding a composite bacterial strain, an enzyme preparation and an inorganic salt to a fermentation raw material to obtain a material to be fermented and fermenting the material;

[0050] The fermentation raw material comprises corn undersize, the composite bacteria comprises Lactobacillus plantarum, Candida utilis and Bacillus subtilis, the enzyme preparation comprises papain, and the inorganic salt comprises ammonium salt, potassium salt, and at least one selected from manganese salt and magnesium salt.

[0051] 2. The method of paragraph 1, wherein the fermentation feedstock comprises corn undercuts and glucose.

[0052] 3. The method as described in paragraph 1 or 2, wherein the water content of the fermentation raw material is 20wt%-60wt%.

[0053] 4. The method according to any one of paragraphs 1 to 3, wherein the pH of the fermentation raw material is adjusted to 5.0-7.0 before adding the composite bacteria, enzyme preparation and inorganic salt.

[0054] 5. The method as described in paragraph 1, wherein the fermentation raw materials include: corn undersize; and one or more selected from corn, soybean meal, soybean hulls, bran, rapeseed meal, distiller's grains, sugar residue, and molasses.

[0055] 6. The method as described in any one of paragraphs 1 to 5, wherein the content of the corn undersize is 10 wt%-90 wt% relative to the total mass of the material to be fermented.

[0056] 7. The method of any one of paragraphs 1-6, wherein the composite bacterial strain consists of Lactobacillus plantarum 1.557, Candida utilis 2.1180 and Bacillus subtilis 1.1413.

[0057] 8. The method as described in paragraph 7, wherein the bacterial count ratio of Lactobacillus plantarum 1.557, Candida utilis 2.1180 and Bacillus subtilis 1.1413 is (40-50):(10-70):(0.5-4).

[0058] 9. The method according to any one of paragraphs 1 to 8, wherein the inoculation amount of the composite bacteria is 0.5%-10%.

[0059] 10. The method of any one of paragraphs 1-9, wherein the inorganic salt comprises an ammonium salt, a potassium salt and a manganese salt, or comprises an ammonium salt, a potassium salt and a magnesium salt.

[0060] 11. The method according to any one of paragraphs 1 to 10, wherein the ammonium salt is one or more selected from the following: ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium nitrate, and ammonium carbonate;

[0061] The potassium salt is one or more selected from the following: potassium sulfate, potassium chloride, potassium nitrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium phosphate;

[0062] The manganese salt is one or more selected from the following: manganese acetate, manganese sulfate, manganese chloride, manganese nitrate;

[0063] The magnesium salt is one or more selected from the following: magnesium sulfate, magnesium chloride, and magnesium nitrate.

[0064] 12. The method according to any one of paragraphs 1 to 11, wherein the amount of the inorganic salt added is 0.3 wt% to 1.0 wt% relative to the total mass of the material to be fermented.

[0065] 13. The method according to any one of paragraphs 1 to 12, wherein the amount of the enzyme preparation added is 0.3 wt% to 1.0 wt% relative to the total mass of the material to be fermented.

[0066] 14. The method of any of paragraphs 1-13, wherein the fermentation is performed at 20°C to 50°C for 1-10 days.

[0067] 15. Use of the corn undersize fermentation product obtained by the method described in any one of paragraphs 1 to 14 in preparing feed.

[0068] 16. A method for preparing corn undersize fermented feed, comprising:

[0069] (1) mixing corn undersize, enzyme preparation and inorganic salt with one or more selected from corn, soybean meal, soybean hull, bran, rapeseed meal, distiller's grains, sugar residue and molasses, wherein the enzyme preparation includes papain, and the inorganic salt includes ammonium salt, potassium salt and at least one selected from manganese salt and magnesium salt;

[0070] (2) inoculating the mixture obtained in step (1) with a composite bacterial strain to obtain a material to be fermented, wherein the composite bacterial strain includes Lactobacillus plantarum, Candida utilis and Bacillus subtilis;

[0071] (3) Fermenting the material to be fermented, and drying, cooling, and crushing the fermentation product to obtain the corn undersize fermented feed.

[0072] 17. The method of paragraph 16, wherein the inorganic salt comprises an ammonium salt, a potassium salt and a manganese salt, or comprises an ammonium salt, a potassium salt and a magnesium salt.

[0073] 18. The method of paragraph 16 or 17, wherein the ammonium salt is one or more selected from the following: ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium nitrate, ammonium carbonate;

[0074] The potassium salt is one or more selected from the following: potassium sulfate, potassium chloride, potassium nitrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium phosphate;

[0075] The manganese salt is one or more selected from the following: manganese acetate, manganese sulfate, manganese chloride, manganese nitrate;

[0076] The magnesium salt is one or more selected from the following: magnesium sulfate, magnesium chloride, and magnesium nitrate.

[0077] 19. The method according to any one of paragraphs 16 to 18, wherein the amount of the inorganic salt added is 0.3 wt% to 1.0 wt% relative to the total mass of the material to be fermented.

[0078] 20. The method according to any one of paragraphs 16 to 19, wherein the amount of the enzyme preparation added is 0.3 wt% to 1.0 wt% relative to the total mass of the material to be fermented.

[0079] 21. The method according to any one of paragraphs 16 to 20, wherein the content of the corn undersize is 10 wt% to 90 wt% relative to the total mass of the material to be fermented.

[0080] 22. The method of any one of paragraphs 16-21, wherein the composite bacterial strain consists of Lactobacillus plantarum 1.557, Candida utilis 2.1180, and Bacillus subtilis 1.1413.

[0081] 23. The method of any one of paragraphs 16-22, wherein the bacterial count ratio of Lactobacillus plantarum 1.557, Candida utilis 2.1180 and Bacillus subtilis 1.1413 is (40-50):(10-70):(0.5-4).

[0082] 24. The method of any one of paragraphs 16-23, wherein the inoculation amount of the composite bacteria is 0.5%-10%.

[0083] 25. The method of any of paragraphs 16-24, wherein the fermentation is performed at 20°C to 50°C for 1-10 days.

[0084] The present invention adopts for the first time a synergistic fermentation process of composite bacteria, papain and inorganic salts and auxiliary addition of inorganic salts, which significantly improves the degradation efficiency of mycotoxins; the degradation rate of aflatoxin B1 in the high-end type (drying) fermented feed obtained by synergistic fermentation of bacteria, enzymes and inorganic salts is 89.00%, the degradation rate of zearalenone is 44.36%, and the degradation rate of vomitoxin is 48.62%, and the comprehensive degradation effect of mycotoxins is significant. Example

[0085] Next, the present invention is further described in detail by examples, but the present invention is not limited to these examples. Unless otherwise specified, the raw materials, reagents, instruments, etc. used in the following examples are conventional commercially available raw materials, reagents, instruments.

[0086] The sources of corn undersize materials used in the following examples and comparative examples, as well as the determination of various indicators, bacterial culture and counting methods are as follows:

[0087] 1. Corn grading and screening and collection of undersize

[0088] Collect screenings from corn processing at COFCO Trading.

[0089] 2. Evaluation of nutritional components and mycotoxin indexes of corn undersize

[0090] 1) Conventional nutritional indicators include: moisture, crude protein, crude fat, crude fiber, crude ash, crude starch, and reducing sugar.

[0091] Conventional index determination method: In the following examples and comparative examples, the moisture content was determined by "GB / T6435 Determination of moisture and other volatile substances in feed", the crude protein on a dry basis was determined by "GBT 6432 Determination of crude protein in feed", the crude fat on a dry basis was determined by "GBT 6433 Determination of crude fat in feed", the crude fiber on a dry basis was determined by "GBT 6434-2007 Determination of crude fiber in feed", the crude ash on a dry basis was determined by "GBT 6438-2007 Determination of crude ash in feed", the crude starch on a dry basis was determined by "GB / T 5009.9-2008 Determination of starch in food", and the reducing sugar on a dry basis was determined by "GB / T 5513-2008 Grain and oil inspection - Determination of reducing sugar and non-reducing sugar in grain".

[0092] Table 1 Test results of conventional nutrient content in corn sieves

[0093]

[0094] 2) Mycotoxins mainly determine the content of aflatoxin B1, vomitoxin and zearalenone in the sieve.

[0095] Mycotoxin determination method: In the following examples and comparative examples, samples were tested for aflatoxin B1, zearalenone (F2 toxin), and vomitoxin using ELISA enzyme-linked immunosorbent assay kits. The determination of aflatoxin B1 refers to the determination method of aflatoxin B1 (Order No.: COKAQ8000) in the RomerLabs Singapore Pte. Ltd. kit, the determination of zearalenone refers to the determination method of zearalenone (Order No.: COKAQ5100) in the Romer Labs Singapore Pte. Ltd. kit, and the determination of vomitoxin refers to the determination method of vomitoxin (Order No.: COKAQ4000) in the Romer Labs Singapore Pte. Ltd. kit. Others refer to GB / T 6682-1992 Specifications and Test Methods for Water Use in Analytical Laboratories and Feed Sampling Standard GB / T 14699.1.

[0096] Table 2 Results of toxin content detection in corn sieves

[0097] Corn Screenings Detection Technology Aflatoxin B1 15.90ppb Colloidal gold test paper method Zearalenone 635.15ppb ELISA Deoxynivalenol 3680.00ppb ELISA

[0098] The national standard "GB 13078-2017 Feed Hygiene Standard" stipulates the following limits for the mycotoxin content of feed raw materials: aflatoxin B1 ≤ 50 ppb, zearalenone (ZEN) ≤ ​​500 ppb, and vomitoxin (DON) ≤ 5000 ppb. Therefore, untreated corn screenings are not suitable as feed raw materials.

[0099] 3. Preparation of shake flask seeds:

[0100] Shake flask seed culture process: prepare the following culture medium, sterilize at 121℃ for 20min, cool the bacterial suspension and inoculate it into the culture medium, culture under the corresponding control parameter conditions, measure OD (wavelength 600nm, cuvette width 1cm) and pH value during the culture process, and when the termination parameters are reached, the shake flask seed culture is completed.

[0101] Lactobacillus:

[0102] Culture medium: 48 g of MRS broth medium in 1000 ml of distilled water, adjusted to pH 6.2 ± 0.1.

[0103] Control parameters: 30°C, anaerobic culture under static conditions.

[0104] Termination parameter: OD ≥ 0.250.

[0105] Yeast:

[0106] Culture medium: 19 g peptone, 19 g glucose, 9.5 g yeast extract, and distilled water to make up to 1000 ml.

[0107] Control parameters: 30℃, 200r / min.

[0108] Termination parameter: OD ≥ 0.320.

[0109] Bacillus:

[0110] Culture medium: 5g yeast powder, 10g peptone, 5g glucose, 10g sodium chloride, 1000ml water. Use 1mol / L NaOH solution to adjust the pH value to alkaline.

[0111] Control parameters: 35℃, 160r / min.

[0112] Termination parameter: OD ≥ 0.120.

[0113] 4. Plate count method:

[0114] The bacterial content was determined by the plate count method. The preparation methods of the plate culture medium used for lactic acid bacteria, yeast, and bacillus were as follows:

[0115] Lactic acid bacteria plate culture medium: weigh 55.2 g / L of MRS broth medium and 10.14 g / L of agar, add distilled water to make up the volume, adjust the pH value to 6.2, sterilize at 120°C for 20 min, make a plate culture medium, and culture for 24 h to ensure no contamination before use.

[0116] Yeast plate culture medium: weigh 10 g / L yeast powder, 20 g / L peptone, 20 g / L glucose, and 14 g / L agar, add distilled water to make up to volume, adjust the pH value to 6.0, sterilize at 120°C for 20 min, make a plate culture medium, and culture for 24 h to ensure no contamination.

[0117] Bacillus plate culture medium: weigh 5 g / L yeast powder, 10 g / L peptone, 5 g / L glucose, 10 g / L sodium chloride, and 20 g / L agar, add distilled water to make up to volume, adjust the pH value to 7.2, sterilize at 120°C for 20 min, make a plate culture medium, and culture for 24 h to ensure no contamination.

[0118] The bacterial content is determined by the plate count method. Weigh 5.0g of the material into 45g of sterile water, place it on a shaker for culture (temperature 32°C, speed 120rpm / min, time 40-50min), then take 0.1ml of the culture solution to 0.9ml of sterile water and shake it well, dilute and spread it on the plate culture medium of the corresponding strain, and place it in a constant temperature box at 30°C for 48h. Counting method: The number of colonies at a dilution is 30-300 colonies. The total number of bacteria in the sample is the number of colonies at that dilution divided by the volume of the dilution solution used for the plate coating (0.1ml), multiplied by the dilution multiple.

[0119] Example 1 Degradation of mycotoxins in corn undersize

[0120] In this example, corn undersize (with an aflatoxin B1 content of 15.9 ppb, a zearalenone content of 635.15 ppb, and a vomitoxin content of 3680 ppb) was purchased from COFCO (Chengdu) Cereals and Oils Industry Co., Ltd.

[0121] 350g corn sieves, 130g distilled water, 5g glucose, and 2.5g inorganic salt (composed of (NH4)2SO4:KH2PO4:MnSO4 in a mass ratio of 2:2:1) were mixed and broken up to obtain a preliminary material. Calcium carbonate (CaCO3) was added to the preliminary material obtained above to adjust its pH to 6.0, and then 10mL of composite bacterial culture liquid was added thereto at an inoculation rate of 2% (volume mass ratio) (wherein, Lactobacillus plantarum 1.557 (purchased from CGMCC): Candida utilis 2.1180 (purchased from CGMCC): Bacillus subtilis 1.1413 (purchased from CGMCC) each had a volume ratio of 3:3:4; wherein, the contents of Lactobacillus plantarum 1.557, Candida utilis 2.1180 and Bacillus subtilis 1.1413 were 6×10 9 cfu / mL, 8×10 9 cfu / mL and 2×10 8 cfu / mL) and 2.5g of papain (purchased from Beijing Solebow Technology Co., Ltd.), and the fermented material (water content of 37wt%) was placed in an airtight breathing bag, which was provided with a one-way exhaust valve, and the gas could only be discharged from the bag to the outside through the one-way exhaust valve. The material was fermented and cultured at 32°C for 4 days.

[0122] According to the method described above, the contents of aflatoxin B1, vomitoxin and zearalenone in the fermented corn undersize were determined, and the results are shown in Table 3.

[0123] Table 3 Toxin content of corn undersize before and after fermentation

[0124] Corn Screenings Fermented corn screenings Degradation rate Aflatoxin B1 15.90ppb 2.78ppb 82.50% Zearalenone 635.15ppb 362.16ppb 42.98% Deoxynivalenol 3680.00ppb 1939.36ppb 47.30%

[0125] It can be seen from the above table that by adding the above-mentioned composite bacteria, protease agent and inorganic salt to the corn undercuts for fermentation, aflatoxin B1, vomitoxin and zearalenone in the corn undercuts can be significantly degraded, and the contents of the above-mentioned toxins in the fermentation product of the corn undercuts thus obtained meet the requirements of the national standard "GB 13078-2017 Feed Hygiene Standard" on the mycotoxin content limit of feed raw materials, so that the fermentation product can be used to prepare feed.

[0126] Example 2 Degradation of mycotoxins in corn undersize

[0127] The corn undersize was fermented as described in Example 1, except that the inorganic salt was adjusted to consist of (NH4)2SO4, KH2PO4 and MgSO4 in a mass ratio of 2:2:1. As a result, the degradation rates of aflatoxin B1, zearalenone and vomitoxin were 82.06%, 42.19% and 46.70%, respectively.

[0128] Example 3 Degradation of mycotoxins in corn undersize

[0129] The corn undersize was fermented as described in Example 1, except that the volume ratio of Lactobacillus plantarum 1.557, Candida utilis 2.1180 and Bacillus subtilis 1.1413 in the composite bacterial culture was adjusted to 3:1:6 (the inoculation density of each bacterial culture was the same as that in Example 1). As a result, the degradation rates of aflatoxin B1, zearalenone and vomitoxin were 81.73%, 41.97% and 46.24%, respectively.

[0130] Example 4 Preparation of feed using microbial fermentation of corn undersize

[0131] In this embodiment, corn undersize (aflatoxin B1 content of 15.9 ppb, zearalenone content of 635.15 ppb, vomitoxin content of 3680 ppb), corn, bran, starch and sugar residue were purchased from COFCO (Chengdu) Cereals and Oils Industry Co., Ltd., white wine grains were purchased from Sichuan Wenjun Distillery Co., Ltd., soybean meal and bean skin were purchased from COFCO Oils (Heze) Co., Ltd., rapeseed meal was purchased from COFCO Oils (Guangyuan) Co., Ltd., beet molasses was purchased from COFCO Sugar Co., Ltd., papain (≥800,000 U / g) was purchased from Beijing Solebow Technology Co., Ltd., and various inorganic salts were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0132] 1) Preparation of high-end microbial fermentation concentrated feed (drying)

[0133] The first-grade seed solution of Lactobacillus plantarum 1.557 (purchased from CGMCC), Candida utilis 2.1180 (purchased from CGMCC) and Bacillus subtilis 1.1413 (purchased from CGMCC) obtained according to the description of the "Preparation method of shake flask seeds" section above (wherein the contents of Lactobacillus plantarum 1.557, Candida utilis 2.1180 and Bacillus subtilis 1.1413 were 6×10 9 cfu / mL, 8×10 9 cfu / mL and 2×10 8 cfu / mL) in a volume ratio of 3:3:4 to obtain a composite bacterial strain mixed solution. Then, 0.5 parts by weight of papain, 0.5 parts by weight of inorganic salt (composed of (NH4)2SO4, KH2PO4 and MnSO4 in a mass ratio of 2:2:1), 30 parts by weight of corn undersize, 26 parts by weight of corn, 30 parts by weight of soybean meal, 2 parts by weight of bean skin, 2 parts by weight of bran, and 6 parts by weight of starch residue were mixed and broken up, and then mixed with 1 part by weight of beet molasses, and 2 parts by weight of the composite bacterial strain mixed solution were added thereto in an inoculation amount of 2% (volume-to-weight ratio) to obtain a material to be fermented.

[0134] The material to be fermented is placed in a breathing bag (an airtight packaging bag provided with a one-way exhaust valve through which gas can only be discharged from the bag to the outside of the bag) with a volume ratio of the material in the breathing bag to the gas sealed in the bag of 10:1. The fermentation is carried out for 96 hours under the following conditions: the oxygen content is 4 vol%, the temperature is 30°C, and the initial pH is 7.

[0135] The product (wet material) obtained by the above fermentation is dried (boiling drying, inlet air temperature 140°C), naturally cooled, crushed and passed through a 20-mesh sieve to obtain a high-end corn undersize fermented concentrated feed (drying).

[0136] 2) Preparation of high-quality corn undersize fermented concentrated feed (drying)

[0137] The first-level seed solution of Lactobacillus plantarum 1.557, Candida utilis 2.1180 and Bacillus subtilis 1.1413 obtained according to the description of the above "Preparation method of shake flask seeds" (wherein the contents of Lactobacillus plantarum 1.557, Candida utilis 2.1180 and Bacillus subtilis 1.1413 are 6×10 9 cfu / mL, 8×10 9 cfu / mL and 2×10 8cfu / mL) in a volume ratio of 3:3:4 to obtain a composite bacterial strain mixed solution. Then, 0.5 parts by weight of papain, 0.5 parts by weight of inorganic salt (composed of (NH4)2SO4, KH2PO4 and MnSO4 in a mass ratio of 2:2:1), 20 parts by weight of corn undersize, 20 parts by weight of corn, 17 parts by weight of starch residue, 25 parts by weight of 95 rapeseed meal, and 14 parts by weight of white wine lees were mixed and broken up, and then mixed with 1 part by weight of beet molasses, and 2 parts by weight of the composite bacterial strain mixed solution were added thereto in an inoculation amount of 2% (volume-to-weight ratio) to obtain a material to be fermented.

[0138] The material to be fermented was placed in a breathing bag with a volume ratio of the material in the breathing bag to the gas sealed in the bag of 10:1, and fermented for 96 hours under the following conditions: oxygen content of 4 vol%, temperature of 30° C., and initial pH of 7.

[0139] The product (wet material) obtained by the above fermentation is dried (boiling drying, air inlet temperature 140°C), naturally cooled, crushed and passed through a 20-mesh sieve to obtain high-quality corn undersize fermentation concentrated feed (drying).

[0140] Next, in the effect example section, the two types of corn undersize fermented concentrated feeds obtained above were evaluated.

[0141] Comparative Example 1 Degradation of mycotoxins in corn undersize

[0142] The corn undersizes were fermented according to the method described in Example 1, except that papain and inorganic salts were not added to the fermented material.

[0143] According to the method described above, the contents of aflatoxin B1, vomitoxin and zearalenone in the fermented corn undersize were determined, and the results are shown in Table 4.

[0144] Table 4 Toxin content of corn undersize before and after fermentation

[0145] Corn Screenings Fermented corn screenings Degradation rate Aflatoxin B1 15.90ppb 9.34ppb 41.26% Zearalenone 635.15ppb 504.12ppb 20.63% Deoxynivalenol 3680.00ppb 2879.23ppb 21.76%

[0146] It can be seen from the above table that when only the composite bacteria were added, the contents of aflatoxin B1, zearalenone and vomitoxin in the corn undersize were slightly reduced after fermentation with the composite bacteria. However, the zearalenone content in the fermented product still exceeded the national standard "GB 13078-2017 Feed Hygiene Standard" on the limit value of zearalenone content in feed raw materials.

[0147] Compared with Examples 1-3, it can be seen that the synergistic fermentation using composite bacteria, enzyme preparations and inorganic salts can more significantly reduce the content of aflatoxin B1, zearalenone and vomitoxin in corn underfeeds than fermenting corn underfeeds using only composite bacteria.

[0148] Comparative Example 2 Degradation of mycotoxins in corn undersize

[0149] In addition to replacing the composite strains used for fermentation with composite strain 1 consisting of Lactobacillus cellobiose 138320 (purchased from BNCC), Candida utilis 2.1180 (purchased from CGMCC), and Bacillus subtilis 1.836 (purchased from CGMCC) (the volume ratio of these three bacterial solutions was 3:3:4; the contents of Lactobacillus cellobiose 138320, Candida utilis 2.1180, and Bacillus subtilis 1.836 were 6×10 9 cfu / mL, 8×10 9 cfu / mL and 2×10 8 cfu / mL) and composite strain 2 consisting of Lactobacillus acidophilus 1.1854 (purchased from CGMCC), Saccharomyces cerevisiae 2.3853 (purchased from CGMCC), and Bacillus subtilis 1.1413 (purchased from CGMCC) (the volume ratio of these three bacterial solutions was 3:3:4, and the contents of Lactobacillus acidophilus 1.1854 (purchased from CGMCC), Saccharomyces cerevisiae 2.3853 (purchased from CGMCC), and Bacillus subtilis 1.1413 were 6×10 9 cfu / mL, 8×10 9 cfu / mL and 2×10 8 cfu / mL), the corn undersize was fermented using composite strain 1 and composite strain 2 respectively according to the method described in Example 1.

[0150] According to the method described above, the contents of aflatoxin B1, vomitoxin and zearalenone in the fermented corn undersize were determined, and the results are shown in Table 5.

[0151] Table 5 Toxin content of corn undersize before and after fermentation

[0152] Corn Screenings Fermented corn screenings (composite strain 1) Degradation rate Fermented corn screenings (composite strain 2) Degradation rate Aflatoxin B1 15.90ppb 13.28ppb 16.48% 13.05 ppb 17.92% Zearalenone 635.15ppb 585.99ppb 7.74% 608.30 ppb 4.23% Deoxynivalenol 3680.00ppb 3400.69ppb 7.59% 3280.00 ppb 10.87%

[0153] It can be seen from the above table that when only the type of composite bacteria was adjusted, the contents of aflatoxin B1, zearalenone and vomitoxin were slightly reduced after the corn undersize was fermented with different composite bacteria. However, the zearalenone content in the fermented product still exceeded the national standard "GB 13078-2017 Feed Hygiene Standard" on the limit value of zearalenone content in feed raw materials.

[0154] Compared with Examples 1-3, it can be seen that compared with fermenting corn underfeeds with other types of composite strains, the use of the specific composite strains of the present invention in conjunction with enzyme preparations and inorganic salts for synergistic fermentation can more significantly reduce the content of aflatoxin B1, zearalenone and vomitoxin in corn underfeeds.

[0155] Comparative Example 3 Degradation of mycotoxins in corn undersize

[0156] The corn undersize was fermented according to the method described in Example 1, except that no inorganic salt was added to the fermented material.

[0157] According to the method described above, the contents of aflatoxin B1, vomitoxin and zearalenone in the fermented corn undersize were determined, and the results are shown in Table 6.

[0158] Table 6 Toxin content of corn undersize before and after fermentation

[0159] Corn Screenings Fermented corn screenings Degradation rate Aflatoxin B1 15.9ppb 5.41ppb 65.97% Zearalenone 635.15ppb 422.25ppb 33.52% Deoxynivalenol 3680ppb 2357.04ppb 35.95%

[0160] It can be seen from the above table that, in the case of adding composite strains and enzyme preparations, the contents of aflatoxin B1, zearalenone and vomitoxin in the corn undersize after fermentation are reduced to different degrees. However, compared with Examples 1-3, it can be seen that the use of the specific composite strains of the present invention in synergistic fermentation with enzyme preparations and inorganic salts can more significantly reduce the contents of aflatoxin B1, zearalenone and vomitoxin in the corn undersize.

[0161] Comparative Example 4 Degradation of mycotoxins in corn undersize

[0162] Except that papain was replaced by neutral protease (activity unit ≥ 800000 U / g, purchased from Beijing Solebow Technology Co., Ltd., usage 0.5 wt%), corn undersize was fermented according to the method described in Example 1. According to the method described above, the aflatoxin B1, vomitoxin and zearalenone contents of the fermented corn undersize were determined, and the results are shown in Table 7.

[0163] Table 7 Toxin content of corn undersize before and after fermentation

[0164] Corn Screenings Fermented corn screenings Degradation rate Aflatoxin B1 15.9ppb 8.03ppb 49.5% Zearalenone 635.15ppb 476.81ppb 24.93% Deoxynivalenol 3680ppb 2705.17ppb 26.49%

[0165] It can be seen from the above table that, when other types of enzyme preparations are used, the contents of aflatoxin B1, zearalenone and vomitoxin in the corn undersize are reduced to different degrees after fermentation. However, compared with Examples 1-3, it can be seen that the use of the specific composite strains of the present invention in synergistic fermentation with enzyme preparations and inorganic salts can more significantly reduce the contents of aflatoxin B1, zearalenone and vomitoxin in the corn undersize.

[0166] Effect Example 1 Detection of Microbial Fermentation Feed from Corn Screenings

[0167] The feed prepared in Example 4 (hereinafter referred to as "high-end fermented feed" or "high-end (drying)", "high-quality fermented feed" or "high-quality (drying)") was tested according to national standards, wherein the moisture content detection standard is based on GB / T 6435-2014, the crude protein content detection standard is based on GB / T 6432-2018, the crude fat content detection standard is based on GB / T 6433-2006, the crude fiber content detection standard is based on GB / T 6434-2006, the crude ash content detection standard is based on GB / T 6438-2007, the acid-soluble protein content detection standard is based on GB / T 22492-2008, the calcium content detection standard is based on GB / T 6436-2002, the phosphorus content detection standard is based on GB / T 6437-2002, and the lactic acid content detection standard is based on GB / T SXA03-FB-016.

[0168] Determination of mycotoxins in hazardous materials: Samples were tested for aflatoxin B1, zearalenone (F2 toxin) and vomitoxin using ELISA kits. The determination of aflatoxin B1 was carried out in accordance with the determination method of aflatoxin B1 (Order No.: COKAQ8000) in the Romer Labs Singapore Pte. Ltd. kit, the determination of zearalenone was carried out in accordance with the determination method of zearalenone (Order No.: COKAQ5100) in the Romer Labs Singapore Pte. Ltd. kit, and the determination of vomitoxin was carried out in accordance with the determination method of vomitoxin (Order No.: COKAQ4000) in the Romer Labs Singapore Pte. Ltd. kit. Others were carried out in accordance with GB / T 6682-1992 Specifications and Test Methods for Water in Analytical Laboratories and GB / T 14699.1, the feed sampling standard.

[0169] Determination of heavy metal and fluorine content in hazardous substances: The lead content detection standard is based on GB / T 13080-2018, the arsenic content detection standard is based on GB / T 13079-2006, the mercury content detection standard is based on GB / T 13081-2006, the chromium content detection standard is based on GB / T 13088-2006, and the fluorine content detection standard is based on GB / T 13083-2018.

[0170] The samples were tested for the content of 18 kinds of amino acids in feed using amino acid analyzer and high performance liquid chromatography. The 18 kinds of amino acids were determined on a dry basis according to GB / T 18246-2019 Determination of Amino Acids in Feed.

[0171] Results and Analysis:

[0172] Table 8 Nutritional composition of corn undersize fermented feed (wt%)

[0173] Fermented concentrate feed type Moisture Crude Protein Crude fat Crude Fiber Coarse ash Amino Acids Acid soluble protein calcium phosphorus lactic acid High-end type (drying) 6.36 27.12 3.97 3.83 6.19 24.98 12.15 0.32 0.37 3.86 High quality type (drying) 6.61 22.16 6.96 7.80 7.93 18.02 14.95 0.46 0.62 3.73

[0174] Table 9 Test results of mycotoxins in feed raw materials (before fermentation) and high-end fermented feed (after fermentation)

[0175] Mycotoxin content before fermentation Mycotoxin content after fermentation Degradation rate Aflatoxin B1 7.91ppb 0.87ppb 89.00% Zearalenone 508.86ppb 283.13ppb 44.36% Deoxynivalenol 1.75ppb 0.90ppb 48.62%

[0176] Table 10 Test results of mycotoxins in feed raw materials (before fermentation) and high-quality fermented feed (after fermentation)

[0177] Mycotoxin content before fermentation Mycotoxin content after fermentation Degradation rate Aflatoxin B1 1.59ppb 0.38ppb 76.09% Zearalenone 201.10ppb 117.06ppb 41.79% Deoxynivalenol 2.18ppb 1.20ppb 45.14%

[0178] Table 11 Heavy metal and fluoride content of fermented feed from corn undersize

[0179]

[0180] Table 12 Amino acid detection of corn undersize fermented feed (wt%)

[0181]

[0182] As can be seen from the table above, after fermentation treatment, the content of aflatoxin B1 in the high-end type (drying) of corn undersize fermented concentrated feed is 0.87 ppb, the content of zearalenone is 283.13 ppb, and the content of vomitoxin is 0.90 ppm; therefore, the degradation rate of aflatoxin B1 in the high-end type (drying) of fermented feed treated with bacteria, enzymes and inorganic salts is 89.00%, the degradation rate of zearalenone is 44.36%, and the degradation rate of vomitoxin is 48.62%, and the comprehensive degradation effect of mycotoxins is significant. The high-end type (drying) of corn undersize fermented concentrated feed meets the relevant standards for toxin quality control in feed, so it can be used in pig compound feed.

[0183] The total amount of amino acids in the high-end type (drying) of corn undercuts fermented concentrated feed is 24.98wt%, and the total amount of amino acids in the high-quality type (drying) is 18.02wt%. In addition, the content of each amino acid in the high-end type (drying) of corn undercuts fermented concentrated feed is generally better than that in the high-quality type (drying), and the amino acid content is more balanced.

[0184] Effect Example 2: In vitro (monogastric animal bionic digestive system) evaluation test of corn undersize fermented feed

[0185] The digestion and absorption characteristics of feed directly reflect the utilization value of feed raw materials and the ability of animals to utilize feed raw materials. The digestion characteristics of feed are mainly evaluated through digestion experiments. By using in vitro analytical enzymatic hydrolysis, protease is used to simulate the digestion process of feed by animals, so as to evaluate the fermented feed of corn undersize prepared in Example 4 in vitro.

[0186] The digestibility of feed raw materials or complete feed is determined by using a monogastric animal bionic digestion instrument and digestive enzyme hydrolysis method.

[0187] According to the manual of the monogastric animal bionic digestion system, stomach buffer, small intestine buffer, large intestine buffer, stomach digestion fluid, small intestine digestion fluid, and large intestine digestion fluid were prepared. Among them, pepsin, trypsin, chymotrypsin, and large intestine enzymes were purchased from Hunan Zhongben Zhinong Technology.

[0188] Put the gastric buffer, small intestine buffer and large intestine buffer into the special bottles provided with the instrument respectively, and place them at the designated positions of the instrument, and then connect the system pipes to the buffer bottles.

[0189] Weigh 2 g of the two feed samples prepared in Example 4 into 10 ml glass test tubes respectively. Use a dialysis bag to simulate the digestive tract, transfer the samples in the glass test tubes into it, rinse the glass test tubes with 20 ml of gastric digestive fluid, and transfer all the rinsing fluid into the dialysis bag. Place the dialysis bag on a digestive tract stand.

[0190] According to the operation manual of the bionic digestion system, enter the gastric digestion stage, small intestine digestion stage and large intestine digestion stage in sequence. After digestion, pour the undigested residue in the dialysis bag into a 90mm culture dish with constant weight, then cut the dialysis bag longitudinally, and rinse the residue remaining on the dialysis bag into the culture dish with deionized water. Bake the culture dish containing the digestion residue at 65°C until there is no water mark, then bake it at 105°C to constant weight, and weigh it. Scrape off all the digestion residue in the culture dish, transfer it to a glass sand crucible with a known absolute dry weight, and weigh it after constant weight at 105°C for 2h. Rinse the residue with anhydrous ethanol 3 times under suction filtration conditions, 30ml each time. After the anhydrous ethanol is basically evaporated, place the glass crucible with defatted undigested residue at 105°C for 2h.

[0191] The results are shown in Table 14 below.

[0192] Effect Example 3 Animal Energy Metabolism Test Results

[0193] The absorption and utilization of exogenous nutrients by animals is currently mainly completed through animal feeding experiments, and the absorption performance of feed is evaluated by utilizing digestible energy.

[0194] Eighteen healthy castrated three-way crossbred pigs (Dor × Long × Long) with an initial body weight of about 55 kg were selected and housed in stainless steel metabolic cages (1.20 × 0.70 × 0.96 m 3 The experimental pigs were randomly divided into two experimental diet groups and one basic diet group, and each treatment was set up with 6 replicates, and each replicate had 1 pig.

[0195] This experiment was conducted in the pig metabolism laboratory of Fengning Animal Experiment Base (Fengning, Hebei). Each experimental period was 7 days, with the first 5 days as an adaptation period and feces and urine collected by the full feces collection method on days 6 to 7. The basal diet of this experiment consisted of corn (76.00%), dehulled soybean meal (21.00%) and premix (3.00%). The composition of the basal diet and experimental diet is shown in Table 13.

[0196] Table 13 Feed formula of experimental diet and basal diet (wt%)

[0197] project Basic diet Test a group Experimental Group 2 corn 76.00 57.00 57.00 Dehulled soybean meal 21.00 15.75 15.75 High-end feed (drying) 24.25 High-quality feed (dried) 24.25 Calcium Hydrogen Phosphate 1.10 1.10 1.10 Stone powder 0.90 0.90 0.90 Sodium chloride 0.30 0.30 0.30 Choline chloride 0.20 0.20 0.20 Vitamin and trace element premix 0.50 0.50 0.50 total 100.00 100.00 100.00

[0198] In this experiment, the total amount of feed for the experimental diet group and the basal diet group was 4wt% of the pig's body weight (Adeola, 2001); equal amounts were fed twice a day at 8:00 and 17:00. During the entire experimental period, the pigs were allowed to drink water freely. During the collection period, the feed intake, food refusal and feed spillage of each pig were accurately recorded. During the entire experimental period, the pig house environment was kept clean and sanitary, and the room temperature was controlled at 22 ± 2℃.

[0199] At the beginning of the collection period, place the manure collecting pan under the pig cage slats to ensure that all the manure discharged by the pig falls into the manure collecting pan. If a small amount of manure falls on the slats, it must be cleaned up completely. Collect the manure discharged by each experimental pig every day, put the manure of each pig in each period into the corresponding plastic bag, and store it in a -20℃ refrigerator immediately after each collection. After the end of the test period, all the manure collected for 5 days was thawed at room temperature, mixed evenly, and weighed. Take 2 300 g small samples from the mixed manure sample of each pig and place them evenly on the baking tray, spray 15 mL of 6 N HCl on the surface of the pig manure for nitrogen fixation, and then put it in a 65℃ oven for 72 hours to air dry state, and rehydrate to constant weight after 24 hours. The dried manure samples were retained according to the pig number, crushed through a 40-mesh sieve, and bagged for analysis.

[0200] When collecting urine samples during the experimental period, place a urine bucket containing 10 mL of 6 N HCl under the metabolic cage to collect urine samples from each pig every day. Place gauze above the urine bucket to prevent feed and feces from falling into the urine samples. Collect urine samples from each pig every morning during the experimental period. Accurately measure the total urine volume of each pig every day, mix it evenly, measure 1wt% of the total urine volume and transfer it to the urine collection bottle, and freeze it in time. After the collection period is over, thaw the 5-day urine sample and transfer it to a bucket to mix it evenly, then take part of the urine sample and put it into a 50 mL centrifuge tube. The urine sample is frozen and stored for testing and analysis.

[0201] The test results are shown in Table 14 below.

[0202] Table 14 In vitro simulated digestion and in vivo energy metabolism of pigs

[0203]

[0204] In the pig in vitro digestion simulation experiment, the energy value of the high-quality (drying) enzymatic hydrolyzate of the corn undercuts fermented feed was 12.0802 MJ / Kg. Furthermore, the energy value of the high-end (drying) enzymatic hydrolyzate of the corn undercuts fermented concentrated feed was 14.8209 MJ / Kg.

[0205] In the digestion experiment in pigs, the digestible energy value of the high-quality (drying) type of corn undercuts fermented feed was 2587 J / g, and further, the digestible energy value of the high-end (drying) type of corn undercuts fermented feed was 3172 J / g. In this article, digestible energy refers to the energy contained in the feed that is digested and absorbed, that is, digestible energy = total energy of feed - feces energy - gas energy such as methane that cannot be used by animals. Therefore, a high digestible energy value means that the energy that can be digested and absorbed in the feed is higher. The digestion and absorption characteristics of the feed determine the efficiency and degree of utilization of the feed by the animal. As can be seen from the above table, the fermented corn undercuts feed (high-quality (drying) and high-end (drying)) described in the present invention both have high digestible energy values, and in particular, the high-end (drying) feed has a higher digestible energy value.

[0206] In the present invention, in terms of simulated digestion data in vitro (dry matter digestibility, digestibility after defatting, energy value of enzymatic hydrolyzate) and in vivo digestion data (digestible energy) of pigs, the high-end corn undercut fermented feed (drying) and the high-quality corn undercut fermented feed (drying) both showed good effects, among which the effect of the high-end corn undercut fermented feed (drying) was more significant. Therefore, after the mycotoxins in corn undercuts are degraded by the method of the present invention, the desired fermented feed can be prepared, thereby improving the utilization value of the corn undercuts.

Claims

1. A method for reducing the mycotoxin content in corn undersize, comprising: Adding composite bacteria, enzyme preparation and inorganic salt to fermentation raw materials to obtain a material to be fermented and fermenting the material; The fermentation raw material comprises corn undersize, and the composite bacteria are composed of Lactobacillus plantarum CGMCC 1.557, Candida utilis CGMCC 2.1180 and Bacillus subtilis CGMCC 1.1413, wherein the bacterial count ratio of Lactobacillus plantarum CGMCC1.557, Candida utilis CGMCC 2.1180 and Bacillus subtilis CGMCC 1.1413 is (40-50):(10-70):(0.5-4); The enzyme preparation includes papain, and the inorganic salt includes ammonium salt, potassium salt, and at least one selected from manganese salt and magnesium salt.

2. The method of claim 1, wherein: The fermentation feedstock comprises corn screenings and glucose.

3. The method according to claim 1 or 2, wherein: The water content of the fermentation raw material is 20wt%-60wt%.

4. The method according to claim 1 or 2, wherein: Before adding the composite bacteria, enzyme preparation and inorganic salt, the pH of the fermentation raw material is adjusted to 5.0-7.

0.

5. The method of claim 1, wherein: The fermentation raw materials include: corn undersize; and one or more selected from corn, soybean meal, soybean hulls, bran, rapeseed meal, distiller's grains, sugar residue, and molasses.

6. The method according to claim 1 or 2, wherein: Relative to the total mass of the material to be fermented, the content of the corn undersize is 10wt%-90wt%.

7. The method according to claim 1 or 2, wherein: The inoculation amount of the composite bacteria is 0.5%-10%.

8. The method according to claim 1 or 2, wherein: The inorganic salt includes ammonium salt, potassium salt and manganese salt, or includes ammonium salt, potassium salt and magnesium salt.

9. The method according to claim 1 or 2, wherein: The ammonium salt is one or more selected from the following: ammonium chloride, ammonium sulfate, ammonium carbonate; The potassium salt is one or more selected from the following: potassium sulfate, potassium chloride, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium phosphate; The manganese salt is one or more selected from the following: manganese acetate, manganese sulfate, manganese chloride; The magnesium salt is one or more selected from the following: magnesium sulfate and magnesium chloride.

10. The method according to claim 1 or 2, wherein: Relative to the total mass of the material to be fermented, the added amount of the inorganic salt is 0.3wt%-1.0wt%.

11. The method according to claim 1 or 2, wherein: Relative to the total mass of the material to be fermented, the added amount of the enzyme preparation is 0.3wt%-1.0wt%.

12. The method according to claim 1 or 2, wherein: The fermentation is carried out at 20°C to 50°C for 1 to 10 days.

13. Use of the corn undersize fermentation product obtained by the method according to any one of claims 1 to 12 in preparing feed.

14. A method for preparing corn undersize fermented feed, comprising: (1) mixing corn undersize, enzyme preparation and inorganic salt with one or more selected from corn, soybean meal, soybean hull, bran, rapeseed meal, distiller's grains, sugar residue and molasses, wherein the enzyme preparation includes papain, and the inorganic salt includes ammonium salt, potassium salt and at least one selected from manganese salt and magnesium salt; (2) inoculating the mixture obtained in step (1) with a composite bacterial strain to obtain a material to be fermented, wherein the composite bacterial strain is composed of Lactobacillus plantarum CGMCC 1.557, Candida utilis CGMCC 2.1180 and Bacillus subtilis CGMCC 1.1413, wherein the bacterial count ratio of Lactobacillus plantarum CGMCC 1.557, Candida utilis CGMCC 2.1180 and Bacillus subtilis CGMCC1.1413 is (40-50):(10-70):(0.5-4); (3) Fermenting the material to be fermented, and drying, cooling, and crushing the fermentation product to obtain the corn undersize fermented feed.

15. The method of claim 14, wherein: The inorganic salt includes ammonium salt, potassium salt and manganese salt, or includes ammonium salt, potassium salt and magnesium salt.

16. The method according to claim 14 or 15, wherein: The ammonium salt is one or more selected from the following: ammonium chloride, ammonium sulfate, ammonium carbonate; The potassium salt is one or more selected from the following: potassium sulfate, potassium chloride, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium phosphate; The manganese salt is one or more selected from the following: manganese acetate, manganese sulfate, manganese chloride; The magnesium salt is one or more selected from the following: magnesium sulfate and magnesium chloride.

17. The method according to claim 14 or 15, wherein: Relative to the total mass of the material to be fermented, the added amount of the inorganic salt is 0.3wt%-1.0wt%.

18. The method of claim 14 or 15, wherein: Relative to the total mass of the material to be fermented, the added amount of the enzyme preparation is 0.3wt%-1.0wt%.

19. The method of claim 14 or 15, wherein: Relative to the total mass of the material to be fermented, the content of the corn undersize is 10wt%-90wt%.

20. The method of claim 14 or 15, wherein: The inoculation amount of the composite bacteria is 0.5%-10%.

21. The method of claim 14 or 15, wherein: The fermentation is carried out at 20°C to 50°C for 1 to 10 days.

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