Method for preparing feed raw material by synergistic fermentation of rapeseed dregs and pomace

Abstract

The invention belongs to the technical field of feed preparation, and particularly relates to a method for preparing a feed raw material through synergistic fermentation of rapeseed dregs and pomace. The method systematically solves the technical problems of anti-nutritional factor residue, pomace decay risk, low fiber utilization rate, unbalanced nutrition and the like of rapeseed meal, and has the core advantages of thoroughness and safety of detoxification, no chemical residue, significantly improved fiber degradation rate, and significantly improved process stability by inhibiting infectious microbe pollution through segmented temperature control. The method provides an industrial feasible path for high-value utilization of the rapeseed dregs and the pomace, and has both economic benefits and environmental benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of feed preparation and relates to a method for preparing feed raw materials by cooperative fermentation of rapeseed meal and pomace. Background Art

[0002] Rapeseed meal is the main by-product of rapeseed oil processing. It is rich in protein (35%-45%) and cellulose. However, it contains anti-nutritional factors such as glucosinolates, condensed tannins, and phytic acid, so it has poor palatability and is highly toxic to animals, limiting its direct and large-scale application in feed processing. Fruit pomace is a by-product of fruit processing. It is rich in pectin, soluble sugars, and cellulose. However, due to its high water content, it is easily corrupted and the cost of processing it separately is high. It is usually discarded or treated at a low value, which easily leads to waste of resources and environmental pollution. In the prior art, the processing methods of rapeseed meal and fruit pomace have the following defects:

[0003] 1) Anti-nutritional factors are difficult to completely remove. Traditional physical (high temperature) detoxification methods easily lead to protein denaturation. Traditional chemical detoxification methods (alkaline treatment) will leave residual alkali metal ions, destroying the palatability of feed and polluting the environment. Single biological fermentation detoxification has problems such as low cellulose degradation rate, limited animal absorption, incomplete detoxification and long fermentation time.

[0004] 2) The high moisture content and perishability of pomace, with a moisture content exceeding 80%, can easily lead to mycotoxin accumulation during silage due to improper pH adjustment. Pomace is rich in carbon sources (fructose and glucose) but lacks nitrogen sources. Fermentation alone results in low protein synthesis rates, and pectin-based substances easily form a gel barrier, hindering microbial access to the substrate.

[0005] 3) Existing technologies mostly process rapeseed meal or fruit by-products separately, without taking advantage of the nutritional complementarity between the two (for example, pectin promotes bacterial enzyme activity and sugar provides a carbon source for fermentation). Therefore, a large amount of additional carbon or nitrogen source is required, which increases the raw material cost of fermentation.

[0006] 4) The process parameters need to be optimized, and there is a lack of systematic research on key parameters such as fermentation temperature, bacteria-enzyme ratio, and substrate mixing ratio, resulting in poor product stability.

[0007] Therefore, providing a method for preparing feed raw materials by co-fermenting rapeseed meal and pomace has become an urgent problem to be solved. Summary of the Invention

[0008] In order to solve the above problems, the present invention provides a method for preparing feed raw materials by co-fermenting rapeseed meal and pomace, and a method for preparing feed containing the above raw materials, which specifically comprises the following steps:

[0009] Step 1: Preprocessing

[0010] The rapeseed meal is crushed into 40-50 mesh, then mixed with the complex enzyme solution at a mass ratio of 1:3, stirred at 50-60°C and 150-200 rpm for 40-60 minutes, and then dehydrated to a moisture content of ≤15% to obtain pretreated rapeseed meal. The mixed pomace is mixed with calcium carbonate at a mass ratio of 100:(1-2) to obtain modified pomace.

[0011] Preferably, the mixed pomace includes, but is not limited to, one or more of passion fruit pomace, pineapple pomace, mango pomace, citrus pomace, roxburghii pomace, apple pomace, sugarcane pomace, grape pomace, tomato pomace, orange pomace, hawthorn pomace, olive pomace, pear pomace, apricot pomace, and watermelon rind. Most preferably, the mixed pomace includes passion fruit pomace, pineapple pomace, apple pomace, and orange pomace, with a mass ratio of 4:2:3:1.

[0012] Preferably, the complex enzyme solution comprises myrosinase, phytase, citric acid and water in a mass ratio of (2-3):(1-2):(2-3):100.

[0013] Step 2: First stage fermentation

[0014] Mix pretreated rapeseed meal, plant straw and bran, add nitrogen source to adjust the C / N ratio to 25-40, then add water to 50-70% moisture content, add composite bacterial agent, ferment at 30-35°C, humidity 65-70%, oxygen flow rate 0.5vvm, and ferment for 36-60h.

[0015] Preferably, the nitrogen source includes but is not limited to fish meal, soybean meal, peptone, silkworm pupa meal, urea and ammonium sulfate. Most preferably, the nitrogen source is urea.

[0016] Preferably, the composite bacterial agent is Bacillus subtilis, Aspergillus niger, Aspergillus oryzae and yeast, with a mass ratio of 2:1:1:1.

[0017] Preferably, the plant straw is one or more of corn straw, soybean straw, wheat straw and rice straw.

[0018] Step 3: Second stage fermentation

[0019] Modified pomace, rice husks and lactic acid bacteria are added to the product of the first stage, and then water is added according to a solid-liquid mass ratio of 1:1. The product is fermented in a closed environment at 35-40°C and a humidity of 60-65% for 24-36 hours, and then fermented in a closed environment at 40-45°C and a humidity of 55-60% for 36-48 hours. After the fermentation is completed, the product is dried at a temperature of ≤55°C to a moisture content of ≤12%, and crushed to 50-60 mesh to obtain the feed raw material.

[0020] Preferably, the mass ratio of the pretreated rapeseed meal, modified pomace, bran, plant straw, rice husk, composite bacterial agent and lactic acid bacteria is (30-40):(30-40):(5-10):(3-7):(5-10):(0.5-1):(0.1-0.2).

[0021] Preferably, the Bacillus subtilis, Aspergillus niger, Aspergillus oryzae, yeast and lactic acid bacteria are all purchased from the market.

[0022] Step 4: Feed preparation

[0023] The feed raw material prepared in step 3 is mixed with calcium hydrogen phosphate and seaweed powder, post-ripened at 40-45° C. for 22-26 hours, dried at 50-55° C. to a moisture content of ≤8%, and then mixed with feed base, antioxidants and trace elements to form granules to obtain a finished feed product.

[0024] Preferably, the mass ratio of the feed base, feed raw materials, calcium hydrogen phosphate, seaweed powder, antioxidant and trace elements is (50-60):(30-40):(1-2):(0.5-1):(0.5-1):(0.05-0.1).

[0025] Preferably, the feed base comprises corn meal, wheat flour, soybean meal, forage grass, sweet potato, potato, fish meal, and mixed vegetables in a mass ratio of 10:4:6:7:3:2:2:5. More preferably, the mixed vegetables include, but are not limited to, one or more of cabbage, lettuce, kale, beets, carrots, pumpkin, and celery. Most preferably, the mixed vegetables are cabbage, celery, carrots, and pumpkin in a mass ratio of 3:2:5:2.

[0026] Preferably, the antioxidant is one or more of tea polyphenols, chitosan, ascorbic acid, astaxanthin and anthocyanidins. Most preferably, the antioxidant is tea polyphenols, chitosan and ascorbic acid in a mass ratio of 1:1:1.

[0027] Preferably, the trace elements are zinc sulfate and ferrous sulfate in a mass ratio of 1:3.

[0028] The present invention has the following advantages:

[0029] (1) Raw material pretreatment and structural modification: Myrosinase, phytase, and water are used to synergistically treat rapeseed cake. The activity of phytase and myrosinase is activated in an acidic environment. Myrosinase initially degrades glucosinolates, while phytase initially degrades phytic acid. Compared with the single fermentation method, the degradation rate of anti-nutritional factors is significantly improved while avoiding alkaline residue. Calcium carbonate is mixed with the pomace to prevent over-acidification, retaining the water and nutrients required for fermentation while also solving the problem of over-acidification.

[0030] (2) Fermentation was carried out in stages to achieve nutritional complementation. In the first stage, aerobic fermentation, rapeseed meal was used as the main ingredient, and plant straw and nitrogen source (urea) were added to precisely control the C / N ratio at 25-40, promoting Bacillus subtilis + Aspergillus + yeast to efficiently degrade cellulose and synthesize bacterial protein.

[0031] In the second stage of anaerobic fermentation, pomace is added to provide a fast-acting carbon source, driving lactic acid bacteria to dominate the fermentation, produce lactic acid, inhibit miscellaneous bacteria and decompose pectin at the same time. The two-stage temperature gradient control activates different strains of bacteria to avoid nutrient loss in single fermentation.

[0032] (3) Resource integration reduces overall costs. The mass ratio of rapeseed meal to pomace is nearly 1:1, maximizing the utilization of two types of cheap by-products. No exogenous sugars (such as fructose or molasses) need to be added throughout the process. Fermentation is driven solely by the sugar content of the pomace itself, significantly reducing costs. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] Example 1

[0035] In step 1, the rapeseed meal is crushed to 45 mesh, then mixed with a complex enzyme solution at a mass ratio of 1:3, stirred at 55°C and 175 rpm for 50 minutes, and then dehydrated to a moisture content of ≤15% to obtain pretreated rapeseed meal. The complex enzyme solution includes myrosinase, phytase, citric acid, and water in a mass ratio of 3:2:2:100.

[0036] The mixed pomace is mixed with calcium carbonate in a mass ratio of 100:1 to obtain modified pomace. The mixed pomace comprises apple pomace, grape pomace, orange pomace and hawthorn pomace in a mass ratio of 4:2:3:1.

[0037] Step 2: Mix the pretreated rapeseed meal, rice straw and bran, add urea to adjust the C / N ratio to 30, then add water to 60% moisture content, add a composite bacterial agent, and ferment for 60 hours at a temperature of 32°C, a humidity of 65%, and an oxygen flow rate of 0.5 vvm; the composite bacterial agent is Bacillus subtilis, Aspergillus niger, Aspergillus oryzae and yeast in a mass ratio of 2:1:1:1.

[0038] Step three, add modified pomace, rice husk and lactic acid bacteria to the product of step two, then add water according to the solid-liquid mass ratio of 1:1, ferment in a closed manner at 37°C and 63% humidity for 36 hours, then ferment in a closed manner at 43°C and 60% humidity for 48 hours, dry at 50°C after fermentation to a moisture content of ≤12%, and crush to 55 mesh to obtain feed raw materials.

[0039] The mass ratio of the pretreated rapeseed meal, modified pomace, bran, plant straw, rice husk, composite bacterial agent and lactic acid bacteria is 40:30:8:5:7:0.5:0.2.

[0040] Step 4: Mix the feed raw materials prepared in step 3 with calcium hydrogen phosphate and seaweed powder, post-ripen at 43° C. for 24 hours, and dry at 55° C. to a moisture content of ≤8%. Then, mix with feed base, antioxidants and trace elements and granulate to obtain a finished feed product.

[0041] The mass ratio of the feed base, feed raw materials, calcium hydrogen phosphate, seaweed powder, antioxidant and trace elements is 55:35:1:0.8:1:0.08.

[0042] The feed base includes corn flour, wheat flour, soybean flour, alfalfa, sweet potato, potato, fish meal, and mixed vegetables in a mass ratio of 10:4:6:7:3:2:2:5. The mixed vegetables are cabbage, celery, carrot, and pumpkin in a mass ratio of 3:2:5:2. The antioxidants are tea polyphenols, chitosan, and ascorbic acid in a mass ratio of 1:1:1. The trace elements are zinc sulfate and ferrous sulfate in a mass ratio of 1:3.

[0043] Test Example 1

[0044] Experimental subjects: 120 healthy three-way hybrid piglets (initial body weight 25±0.5kg) were randomly divided into 4 groups, 30 in each group.

[0045] Group design:

[0046] Experimental group: feed product prepared according to the method of Example 1.

[0047] Control group 1: the finished feed was prepared according to step 4 of Example 1, and the feed raw material was replaced with an equal amount of soybean meal.

[0048] Control group 2: Pig feed produced by Shandong Qilu Zhongmu Biotechnology Co., Ltd. (main nutrients: corn, soybean meal, rapeseed meal, peanut meal and bran).

[0049] Control group 3: The finished feed was prepared according to the method of Example 1, but the rapeseed meal and pomace were directly mixed after pretreatment without the fermentation step (ie, without step 2 and step 3).

[0050] Feeding and management: The experimental period was 60 days, with free access to food and water. The ambient temperature was 25±2℃ and the humidity was 60±5%. The feed intake was recorded daily, and the animals were weighed every 10 days. The morbidity and mortality rates were recorded.

[0051] Experimental steps:

[0052] 1. Pre-experimental period (7 days)

[0053] All piglets were fed a uniform basic diet (piglet premix produced by Tianjin Zhengbang Feed Co., Ltd.), acclimatized to the environment, vaccinated and dewormed.

[0054] 2. Formal experimental period (60 days)

[0055] Daily procedures: Feed animals three times a day at 07:00, 14:00, and 19:00, and record the remaining feed amount for each group (calculate actual feed intake). Observe the animals' mental state, fecal morphology, and disease status.

[0056] Data collection: Fasting weight was measured in the morning on days 0, 30, and 60. Feed-to-meat ratio was calculated as: total feed intake (kg) / total weight gain (kg).

[0057] Sample analysis: After the experiment, the ileum digesta were collected to determine the crude protein and crude fiber digestibility (GB / T method).

[0058] 3. Health Monitoring

[0059] Diarrhea determination: Diarrhea is defined as stool water content >80% and lasting for more than 2 days.

[0060] Dead pigs should be dissected immediately to record the cause.

[0061] Experimental results data

[0062] Table 1 Comparison of growth performance

[0063] Experimental group Control group 1 Control group 2 Control group 3 Final weight (kg) 98.2±2.1 98.5±1.8 87.3±2.0 82.6±3.2 Daily weight gain (g) 1220±25 1075±30 1038±28 958±35 Daily feed intake (kg) 2.85±0.15 2.90±0.12 2.88±0.14 2.82±0.18 Feed-to-meat ratio 2.34±0.08 2.70±0.10 2.77±0.09 2.94±0.12 Diarrhea rate (%) 3.3％ 10％ 12.5％ 18.3％

[0064] Table 2 Digestibility of feed nutrients (%)

[0065] Experimental group Control group 1 Control group 3 crude protein 84.2±1.5 76.8±2.0 68.3±2.5 crude fiber 62.7±1.8 51.2±1.6 45.6±2.1 calcium 75.4±1.2 70.1±1.5 65.8±1.8

[0066] As can be seen from Tables 1-2, the feed prepared with pomace and rapeseed meal as raw materials of the present invention can significantly reduce the feed-to-meat ratio. The feed-to-meat ratio of the experimental group is reduced by 13.3% compared with the soybean meal group, because the synergistic fermentation improves the crude protein / crude fiber digestibility (Table 2) and reduces ineffective intake. The quick-acting carbon source of pomace promotes the metabolism of lactic acid bacteria, generates short-chain fatty acids and improves energy utilization. The feed prepared with pomace and rapeseed meal as raw materials of the present invention has outstanding growth advantages, and the daily weight gain is increased by 13.5% compared with the soybean meal group, because the detoxification is thorough and the bacterial protein synthesis rate is improved. The diarrhea rate of experimental group 1 is the lowest, because lactic acid bacteria inhibit intestinal pathogens and pectin degradation eliminates the gel barrier.

[0067] The present invention can be implemented or used. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing feed raw materials by co-fermenting rapeseed meal and pomace, characterized in that: The following steps are involved: Step 1: crushing rapeseed meal, mixing and stirring with a complex enzyme solution, and then dehydrating to a moisture content of ≤15% to obtain pretreated rapeseed meal; mixing the mixed pomace with calcium carbonate; Step 2: pretreated rapeseed meal, plant straw and bran are mixed, a nitrogen source is added to adjust the C / N ratio to 25-40, water is added to a moisture content of 50-70%, and a composite bacterial agent is added. The temperature is 30-35°C, the humidity is 65-70%, the oxygen flow rate is 0.5 vvm, and the fermentation is carried out for 36-60 hours; Step 3: Add modified pomace, rice husks and lactic acid bacteria to the product of step 2, add water, and ferment in a closed manner at 35-40°C and 60-65% humidity for 24-36 hours, then ferment in a closed manner at 40-45°C and 55-60% humidity for 36-48 hours. After fermentation, dry at a temperature ≤ 55°C to a moisture content ≤ 12%, and crush to 50-60 mesh to obtain a feed raw material; The mass ratio of the pretreated rapeseed meal, modified pomace, bran, plant straw, rice husk, composite bacterial agent and lactic acid bacteria is (30-40):(30-40):(5-10):(3-7):(5-10):(0.5-1):(0.1-0.2).

2. The method for preparing feed raw materials by synergistic fermentation of rapeseed meal and pomace according to claim 1, characterized in that: The complex enzyme solution in step 1 comprises myrosinase, phytase, citric acid and water in a mass ratio of (2-3):(1-2):(2-3):

100.

3. The method for preparing feed raw materials by synergistic fermentation of rapeseed meal and pomace according to claim 1, characterized in that: The mixed fruit pomace described in step 1 comprises one or more of passion fruit pomace, pineapple pomace, mango pomace, citrus pomace, roxburghii pomace, apple pomace, sugarcane pomace, grape pomace, tomato pomace, orange pomace, hawthorn pomace, olive pomace, pear pomace, apricot pomace and watermelon rind.

4. The method for preparing feed raw materials by synergistic fermentation of rapeseed meal and pomace according to claim 3, characterized in that: The mixed pomace is passion fruit pomace, pineapple pomace, apple pomace and orange pomace, and the mass ratio is 4:2:3:

1.

5. The method for preparing feed raw materials by synergistic fermentation of rapeseed meal and pomace according to claim 1, characterized in that: The nitrogen source in step 2 includes fish meal, soybean meal, peptone, silkworm pupa powder, urea and ammonium sulfate.

6. The method for preparing feed raw materials by synergistic fermentation of rapeseed meal and pomace according to claim 1, characterized in that: The composite bacterial agent in step 2 is Bacillus subtilis, Aspergillus niger, Aspergillus oryzae and yeast, with a mass ratio of 2:1:1:

1.

7. A feed raw material prepared by the method according to any one of claims 1 to 6.

8. The method for preparing finished feed from the feed raw material according to any one of claims 1 to 7, characterized in that: The prepared feed raw materials are mixed with calcium hydrogen phosphate and seaweed powder, after-ripened at 40-45°C for 22-26 hours, dried at 50-55°C to a moisture content of ≤8%, and then mixed with feed base, antioxidants and trace elements to form granules to obtain finished feed; The mass ratio of the feed base, feed raw materials, calcium hydrogen phosphate, seaweed powder, antioxidant and trace elements is (50-60):(30-40):(1-2):(0.5-1):(0.5-1):(0.05-0.1).

9. The method for preparing a finished feed according to claim 8, characterized in that: The feed base includes corn flour, wheat flour, soybean flour, forage grass, sweet potato, potato, fish meal and mixed vegetables, with a mass ratio of 10:4:6:7:3:2:2:

5.

10. The finished feed prepared by the method according to any one of claims 8 to 9.