Fermented feed for improving natural antibacterial property and antioxidant property of duck eggs

Abstract

This invention discloses a fermented feed for improving the natural antibacterial and antioxidant properties of duck eggs. The fermented feed is prepared through a two-stage fermentation process using a fermentation substrate comprising the following components in parts by weight: 35-60 parts corn, 15-30 parts soybean meal, 5-15 parts wheat bran, 4-10 parts rice bran, 5-9 parts extruded flaxseed, 2-6 parts grape seed meal, 1-4 parts moringa flavonoid powder, 0.5-2.5 parts dicalcium phosphate, 0.5-3 parts limestone powder, 0.1-0.5 parts salt, and 0.1-0.8 parts compound premix. The two-stage fermentation involves first inoculating with Bacillus for aerobic fermentation, followed by inoculation with lactic acid bacteria and the addition of chitosan oligosaccharides for anaerobic fermentation. This invention significantly increases the content of active proteins such as lysozyme and ovotransferrin in duck egg white, enhancing its antibacterial properties and antioxidant capacity, and providing an efficient and economical technical path for the development of highly active duck egg white raw materials.

Description

Technical Field

[0001] This invention belongs to the field of feed processing and breeding technology, specifically relating to a fermented feed that improves the natural antibacterial and antioxidant properties of duck eggs. Background Technology

[0002] Duck egg white is a nutrient-rich protein resource, containing abundant lysozyme, ovotransferrin, ovalbumin, and other bioactive proteins. Besides providing basic nutrition, these active proteins also demonstrate significant potential as natural antibacterial and antioxidant agents, making them promising for applications in high-value-added fields such as functional foods and pharmaceutical materials. With increasing consumer preference for clean-label products and growing concern about the safety of chemical additives, developing end products with natural, long-lasting antibacterial and antioxidant properties has become an industry trend. Therefore, market demand for duck egg white raw materials is shifting from ordinary nutritional needs to high-value functional applications.

[0003] However, current research mainly focuses on the downstream processing and component extraction of duck egg white. For example, techniques such as ionic strength regulation are used to separate and purify single-function proteins like lysozyme and ovotransferrin; and salt-tolerant bacteria fermentation is used to desalinate salted duck egg white, improving the antioxidant activity of the fermentation products. The core of these technologies lies in the downstream processing of egg white products, which is cumbersome, costly, and difficult to retain the natural synergistic effects of all active components in egg white.

[0004] In the field of duck egg farming and feed formulation, existing technologies mainly focus on improving the production performance of ducks, such as egg production rate, feed conversion ratio, gut health, and eggshell quality. For example, some studies have shown that adding antimicrobial peptides to feed or using fermented feed can improve the immunity and antioxidant capacity of ducks to some extent. However, these studies mostly focus on improving the duck's own condition or general egg quality indicators, without taking the targeted enhancement of natural antibacterial and antioxidant active ingredients in duck egg whites as a core nutritional regulation target.

[0005] In summary, there is a clear technological disconnect between the existing technologies: back-end processing technology focuses on "extracting" active ingredients from egg white, while front-end nutritional regulation technology focuses on improving "production performance." Neither of these technologies can solve the problem of how to safely and efficiently empower laying ducks from the source—that is, through feed nutrition regulation—so that they can directly synthesize and deposit egg white with high functional activity during the egg-laying process.

[0006] Therefore, developing a fermented feed that can directly increase the content of natural active proteins in duck egg whites and simultaneously enhance the functionality of egg whites can not only provide a new path for the development of highly active egg white raw materials, but also provide a higher-performance and lower-cost natural protein source for the functional food and biopharmaceutical fields, which has important economic value and social significance. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a fermented feed that enhances the natural antibacterial and antioxidant properties of duck egg white. This fermented feed, through a specific formula and fermentation process, can promote the synthesis and deposition of highly active antibacterial and antioxidant egg white proteins in laying ducks from the source, thereby enhancing the functionality of egg white.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A fermented feed for laying ducks is prepared by a method comprising the following steps: (1) Preparation of fermentation substrate The fermentation substrate comprises the following components in parts by weight: 35-60 parts corn, 15-30 parts soybean meal, 5-15 parts wheat bran, 4-10 parts rice bran, 5-9 parts puffed flaxseed, 2-6 parts grape seed meal, 1-4 parts moringa flavonoid powder, 0.5-2.5 parts dicalcium phosphate, 0.5-3 parts limestone powder, 0.1-0.5 parts salt, and 0.1-0.8 parts compound premix. (2) Two-stage fermentation of the fermentation substrate. First stage: Inoculate the fermentation substrate with Bacillus bacteria for aerobic fermentation; Second stage: Inoculate lactic acid bacteria into the material after the first stage of fermentation and add chitosan oligosaccharide for anaerobic fermentation.

[0009] Furthermore, the Bacillus is selected from one or more of Bacillus amyloliquefaciens, Bacillus licheniformis, and Bacillus subtilis; the lactic acid bacteria is selected from one or more of Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus casei, Pediococcus pentosaceus, and Bifidobacterium.

[0010] Preferably, the Bacillus is a combination of Bacillus amyloliquefaciens and Bacillus licheniformis; the lactic acid bacteria is a combination of Lactobacillus plantarum and Pediococcus pentosaceus.

[0011] Further, the inoculation amount of Bacillus is 0.1-0.5% of the weight of the fermentation substrate; the inoculation amount of Lactic acid bacteria is 0.1-0.5% of the weight of the fermentation substrate; and the amount of chitosan oligosaccharide is 0.03-0.2% of the weight of the fermentation substrate.

[0012] Furthermore, the fermentation conditions for the first stage are: moisture content 30-40%, temperature 35-40℃, fermentation time 12-24 h, and intermittent ventilation; the fermentation conditions for the second stage are: temperature 30-35℃, and closed anaerobic fermentation for 24-48 h.

[0013] Further, the fermentation substrate comprises the following components in parts by weight: 42-50 parts corn, 18-25 parts soybean meal, 6-12 parts wheat bran, 6-10 parts rice bran, 6-8 parts puffed flaxseed, 3-5 parts grape seed meal, 2-3 parts moringa flavonoid powder, 1-2 parts dicalcium phosphate, 0.7-1.5 parts limestone powder, 0.3-0.5 parts salt, and 0.2-0.6 parts compound premix.

[0014] According to a specific embodiment of the present invention, the preparation method of the fermented feed for laying ducks is as follows: (1) Preparation of fermentation substrate The fermentation substrate comprises the following components in parts by weight: 46 parts corn, 20 parts soybean meal, 10 parts wheat bran, 8 parts rice bran, 7 parts puffed flaxseed, 4 parts grape seed meal, 2 parts moringa flavonoid powder, 1.2 parts dicalcium phosphate, 1 part limestone powder, 0.3 parts salt, and 0.5 parts compound premix. (2) Two-stage fermentation of the fermentation substrate. First stage: Inoculate the fermentation substrate with 0.15% Bacillus amyloliquefaciens and 0.1% Bacillus licheniformis, adjust the moisture content to 30-40%, intermittently ventilate, and ferment at 35-40℃ for 12 h; Second stage: Inoculate the material after the first stage of fermentation with 0.2% Lactobacillus plantarum and 0.1% Pediococcus pentosaceus, and add 0.08% chitosan oligosaccharide. Ferment in a sealed container at 30-35℃ for 30 hours. After fermentation, dry the material to a moisture content of 10-12% to obtain the finished feed.

[0015] The present invention also provides the application of the fermented feed in improving the natural antibacterial and antioxidant properties of duck eggs.

[0016] The beneficial effects of this invention are: This invention, through a specific fermentation formula and process, significantly increases the content of natural active proteins such as lysozyme and ovotransferrin in the egg white of laying ducks after consumption, achieving a synergistic enhancement of the egg white's natural antibacterial and antioxidant properties. While improving the functionality of the egg white, this fermented feed also considers palatability and its impact on the growth performance of laying ducks, which is beneficial for increasing feed intake and feed utilization, maintaining intestinal health, and demonstrating the comprehensive advantages of balancing functionality and production. This invention also has advantages such as controllable cost and environmental friendliness, providing an efficient, economical, and industrially scalable technical path for the development of highly active duck egg white raw materials and functional proteins, with broad market application prospects. Detailed Implementation

[0017] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and not to limit the scope of protection of the present invention. Various modifications or equivalent substitutions made by those skilled in the art based on the following embodiments should also be considered to fall within the scope of protection of the present invention. Experimental methods in the following embodiments that do not specify specific conditions are generally implemented under conventional conditions or according to the methods recommended in the manufacturer's operation manual.

[0018] Materials: Chitosan oligosaccharide is feed grade, obtained through targeted degradation by a complex enzyme; number average molecular weight is 500-3000 Da. All microorganisms are commercially available products; the microbial powder content is 10%. 8 -10 12 CFU / g. The compound premix is ​​a commercially available product, primarily used to supplement trace elements. Its components include feed-grade inorganic salts or organic chelates containing iron, copper, manganese, zinc, iodine, and selenium, as well as vitamins A, D3, E, K3, B vitamins, nicotinamide, calcium pantothenate, folic acid, biotin, choline chloride, DL-methionine, and L-lysine hydrochloride. The commercial duck feed was purchased from Shanghai Nonghao Feed Co., Ltd., and its components are corn, soybean meal, wheat bran, rapeseed meal, fish meal, dicalcium phosphate, limestone powder, salt, and compound premix.

[0019] This invention provides a fermented feed, mainly used to improve the natural antibacterial and antioxidant properties of duck egg whites. It is obtained by adding microbial agents to a substrate for fermentation. The fermentation substrate consists of the following components: 35-60 parts corn, 15-30 parts soybean meal, 5-15 parts wheat bran, 4-10 parts rice bran, 5-9 parts puffed flaxseed, 2-6 parts grape seed meal, 1-4 parts moringa flavonoid powder, 0.5-2.5 parts dicalcium phosphate, 0.5-3 parts limestone powder, 0.1-0.5 parts salt, and 0.1-0.8 parts compound premix.

[0020] Corn and soybean meal form the main energy-protein framework of the feed, ensuring the basic nutrition required for egg production in laying ducks. Meanwhile, the fermentable sugars provided by corn and the protein matrix provided by soybean meal together provide ample carbon and nitrogen sources for the metabolic activities of microorganisms during fermentation. Wheat bran and rice bran provide dietary fiber and trace elements, while also improving the physical properties of the fermentation substrate. The polyphenols / flavonoids in moringa flavonoid powder and grape seed meal, synergistically with the ω-3 fatty acids in extruded flaxseed, influence the physiological state of laying ducks through both antioxidant and anti-inflammatory pathways, providing endogenous support for enhancing egg white functionality. Calcium dicalcium phosphate and limestone powder supplement calcium and phosphorus, which are crucial for eggshell formation.

[0021] Fermentation is carried out in two stages. The first stage involves aerobic fermentation by inoculating with Bacillus; the second stage involves anaerobic fermentation by inoculating with lactic acid bacteria and adding chitosan oligosaccharides. After fermentation, the product is dried to obtain the finished feed. The Bacillus includes one or more of Bacillus amyloliquefaciens, Bacillus licheniformis, and Bacillus subtilis; the lactic acid bacteria include one or more of Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus casei, Pediococcus pentosaceus, and Bifidobacterium.

[0022] This invention employs a two-stage sequential fermentation process: In the first stage, Bacillus secretes enzymes to pre-digest the feed substrate, degrading macromolecular proteins into small peptides and amino acids, providing a high-quality nitrogen source for ducks to synthesize functional proteins, and creating a suitable foundation for subsequent lactic acid bacteria fermentation; In the second stage, lactic acid bacteria are inoculated, which, together with chitosan oligosaccharides, produce acid, bacteriocins, and short-chain fatty acids, improving the intestinal microecology and reducing oxidative stress, thereby promoting the deposition of antibacterial and antioxidant active ingredients in egg white.

[0023] Chitosan oligosaccharide plays a dual role in this invention: firstly, as a prebiotic, it is selectively utilized by lactic acid bacteria in the second stage to promote the production of short-chain fatty acids and bacteriocins, thereby optimizing the intestinal microecology; secondly, as an active signaling molecule, it regulates the intestinal immune and redox states of ducks, reduces inflammation and oxidative stress, thereby indirectly promoting the synthesis and secretion of active substances, and ultimately enhancing the natural antibacterial and antioxidant properties of egg white.

[0024] Example 1 Mix 38 kg of corn, 25 kg of soybean meal, 12 kg of wheat bran, 6 kg of rice bran, 8 kg of puffed flaxseed, 5 kg of grape seed meal, 3 kg of moringa flavonoid powder, 1 kg of dicalcium phosphate, 0.7 kg of limestone powder, 0.5 kg of salt, and 0.8 kg of compound premix to prepare the fermentation substrate.

[0025] In the first stage, 0.3 kg of Bacillus amyloliquefaciens and 0.1 kg of Bacillus subtilis (0.4%) were inoculated, and the moisture content was adjusted to 30-40%. Intermittent ventilation was carried out, and fermentation was carried out at 35-40℃ for 12 h. In the second stage, 0.1 kg each of Lactobacillus plantarum, Lactobacillus acidophilus, and Lactobacillus casei (0.3%) were inoculated, and 0.12 kg of chitosan oligosaccharide was added. Fermentation was carried out in a sealed environment at 30-35℃ for 30 h. After fermentation, the product was dried to a moisture content of 10-12% to obtain the finished feed.

[0026] Example 2 Mix 55 kg of corn, 15 kg of soybean meal, 8 kg of wheat bran, 8 kg of rice bran, 5 kg of puffed flaxseed, 2 kg of grape seed meal, 2 kg of moringa flavonoid powder, 2 kg of dicalcium phosphate, 2 kg of limestone powder, 0.5 kg of salt, and 0.5 kg of compound premix to prepare the fermentation substrate.

[0027] In the first stage, 0.1 kg of Bacillus subtilis and 0.05 kg of Bacillus licheniformis (0.15%) were inoculated, and the moisture content was adjusted to 30-40%. Intermittent ventilation was carried out, and fermentation was carried out at 35-40℃ for 12 hours. In the second stage, 0.3 kg of Bifidobacterium and 0.2 kg of Lactobacillus acidophilus (0.5%) were inoculated, and 0.04 kg of chitosan oligosaccharide was added. Fermentation was carried out in a sealed environment at 30-35℃ for 30 hours. After fermentation, the product was dried to a moisture content of 10-12% to obtain the finished feed.

[0028] Example 3 Mix 46 kg of corn, 20 kg of soybean meal, 10 kg of wheat bran, 8 kg of rice bran, 7 kg of puffed flaxseed, 4 kg of grape seed meal, 2 kg of moringa flavonoid powder, 1.2 kg of dicalcium phosphate, 1 kg of limestone powder, 0.3 kg of salt, and 0.5 kg of compound premix to prepare the fermentation substrate.

[0029] In the first stage, 0.15 kg of Bacillus amyloliquefaciens and 0.1 kg of Bacillus licheniformis (0.25%) were inoculated, and the moisture content was adjusted to 30-40%. Intermittent ventilation was carried out, and fermentation was carried out at 35-40℃ for 12 h. In the second stage, 0.2 kg of Lactobacillus plantarum and 0.1 kg of Pediococcus pentosaceus (0.3%) were inoculated, and 0.08 kg of chitosan oligosaccharide was added. Fermentation was carried out in a sealed environment at 30-35℃ for 30 h. After fermentation, the product was dried to a moisture content of 10-12% to obtain the finished feed.

[0030] Example 4 Mix 40 kg of corn, 30 kg of soybean meal, 6 kg of wheat bran, 5 kg of rice bran, 9 kg of puffed flaxseed, 3 kg of grape seed meal, 4 kg of moringa flavonoid powder, 1.5 kg of dicalcium phosphate, 1 kg of limestone powder, 0.3 kg of salt, and 0.2 kg of compound premix to prepare the fermentation substrate.

[0031] In the first stage, 0.2 kg of Bacillus amyloliquefaciens and 0.1 kg of Bacillus licheniformis (0.3%) were inoculated, and the moisture content was adjusted to 30-40%. Intermittent ventilation was carried out, and fermentation was carried out at 35-40℃ for 12 hours. In the second stage, 0.2 kg of Pediococcus pentosaceus and 0.1 kg of Bifidobacterium were inoculated, and 0.18 kg of chitosan oligosaccharide was added. Fermentation was carried out in a sealed environment at 30-35℃ for 30 hours. After fermentation, the product was dried to a moisture content of 10-12% to obtain the finished feed.

[0032] Comparative Example 1 The feed is prepared by directly and uniformly mixing 46 kg of corn, 20 kg of soybean meal, 10 kg of wheat bran, 8 kg of rice bran, 7 kg of extruded flaxseed, 4 kg of grape seed meal, 2 kg of moringa flavonoid powder, 1.2 kg of dicalcium phosphate, 1 kg of limestone powder, 0.3 kg of salt, 0.5 kg of compound premix, 0.15 kg of Bacillus amyloliquefaciens, 0.1 kg of Bacillus licheniformis, 0.2 kg of Lactobacillus plantarum, 0.1 kg of Pediococcus pentosaceus, and 0.08 kg of chitosan oligosaccharide without fermentation.

[0033] Comparative Example 2 The following ingredients were mixed: 46 kg corn, 20 kg soybean meal, 10 kg wheat bran, 8 kg rice bran, 7 kg extruded flaxseed, 4 kg grape seed meal, 2 kg moringa flavonoid powder, 1.2 kg dicalcium phosphate, 1 kg limestone powder, 0.3 kg salt, 0.5 kg compound premix, 0.15 kg Bacillus amyloliquefaciens, 0.1 kg Bacillus licheniformis, 0.2 kg Lactobacillus plantarum, 0.1 kg Pediococcus pentosaceus, and 0.08 kg chitosan oligosaccharide. All ingredients were then fermented to a moisture content of 30-40% in a sealed container at 30-35℃ for 30 hours. After fermentation, the mixture was dried to a moisture content of 10-12% to obtain the finished feed.

[0034] Test case 1. Animal grouping and feeding The experimental animals were healthy 180-day-old Shaoxing ducks. Before enrollment, they were uniformly quarantined and numbered, and randomly grouped into groups of 50 ducks each, based on similar physical condition. The ducks were housed separately in the same duck house, with identical management conditions except for the composition of their diet. They had free access to feed and water, were fed regularly, and maintained a well-ventilated, hygienic, disinfected, and stable lighting environment. All ducks underwent a 14-day acclimatization period, followed by a 56-day formal experiment. During the acclimatization period, they gradually adapted to the experimental diet and environment, while during the formal experiment, they were continuously fed the corresponding fermented feed. On the last day of the experiment, six fresh duck eggs were randomly collected from each group, numbered, and the egg whites were separated for the determination of lysozyme, ovalferrin, antibacterial activity, and antioxidant activity. Each indicator was measured in triplicate, and the average value was taken. Finally, the average value of the six duck eggs was taken. One-way ANOVA was performed using SPSS software, and Tukey's HSD test was used for multiple comparisons between groups. The significance level was set at P < 0.05.

[0035] 2. Indicator Measurement (1) Lysozyme content determination: The lysozyme content in duck egg white was determined using a commercial sandwich ELISA kit. 1.0 mL of duck egg white sample was taken, mixed thoroughly, diluted appropriately with sample diluent according to the kit requirements, centrifuged, and the supernatant was added to the ELISA plate according to the kit instructions. The absorbance was measured at 450 nm, and the lysozyme content was calculated based on the standard curve.

[0036] (2) Determination of ovotransferrin content: The ovotransferrin content in duck egg white was determined using a commercial double-antibody sandwich ELISA kit. 1.0 mL of duck egg white sample was taken, thoroughly mixed, and diluted with sample diluent according to the specified ratio. If necessary, the supernatant was collected by centrifugation. The standard and sample were added to a pre-coated antibody-impregnated ELISA plate for reaction. After washing, color development, and termination, the absorbance was measured at 450 nm. The ovotransferrin content in duck egg white was calculated based on the standard curve.

[0037] (3) Antibacterial rate determination: Take 1.0 mL of fresh egg white, mix thoroughly, and centrifuge at 4 ℃ and 8000 r / min for 10 min. Take the supernatant as the sample to be tested. Antibacterial rate determination against Escherichia coli and Staphylococcus aureus: Inoculate the activated bacterial suspension into liquid culture medium, and set up sample group and blank control group respectively. Add 100 μL of bacterial suspension and 4.8 mL of liquid culture medium to each group; add 100 μL of egg white supernatant to the sample group and add 100 μL of sterile water to the control group. After shaking culture at 37 ℃ for 18-24 h, measure the absorbance (OD value) at 600 nm and calculate the antibacterial rate according to the following formula:

[0038] In the formula, The absorbance of the blank control group is shown. The absorbance of the sample group is given.

[0039] (4) Determination of total antioxidant capacity: Take 100 μL of egg white sample solution and react according to the instructions of the total antioxidant kit. Usually, the sample solution is mixed with the working solution and reacted at 37 ℃ for a certain time. The absorbance is measured at the specified wavelength. The total antioxidant capacity is calculated based on the standard or standard curve. If the kit is used, the calculation is as follows:

[0040] In the formula, The absorbance of the sample. This represents the absorbance of the blank sample. Standard absorbance, The absorbance is the standard blank absorbance. This refers to the enzyme activity units corresponding to the concentration of the standard solution. This refers to the sample dilution factor.

[0041] 3. Test Results As shown in Table 1, the fermented feed prepared by this invention significantly promotes the enrichment of natural antibacterial and antioxidant active proteins in duck egg white. Its effect is not only superior to commercial duck feed but also to the comparative feed that is unfermented or undergoes a single fermentation. This invention improves the digestibility and utilization efficiency of functional nutrients in laying ducks and promotes the accumulation of active proteins in egg white by optimizing the feed formulation and controlling the dominant microbial flora and its metabolic direction in stages. In the first stage, Bacillus is selected, utilizing its strong enzyme secretion capacity to preferentially decompose proteins and antinutritional factors in the fermentation substrate, releasing small molecule peptides, oligosaccharides, and available nutrient substrates. Simultaneously, Bacillus can improve substrate structure and increase feed digestibility during fermentation, which is beneficial for the absorption and transport of nutrients and functional components in the duck's intestines. In the second stage, lactic acid bacteria are inoculated to rapidly produce acid, inhibit other bacteria, stabilize the fermentation system, and further generate organic acids, small molecule metabolites, and functional factors beneficial to improving the intestinal microecology, thereby enhancing the biological value of the feed. This combination of Bacillus first and Lactobacillus later allows the two types of bacteria to function in their respective suitable environments, avoiding competition and interference between different species on substrates, pH, and growth space during one-step mixing, thus facilitating the formation and utilization of functional components.

[0042] Table 1. Lysozyme and ovotransferrin content in duck egg whites from different groups

[0043] Note: Different lowercase letters indicate significant differences between groups (P<0.05); the same letter indicates no significant difference.

[0044] As shown in Table 2, the fermented feed prepared by this invention significantly promotes the antibacterial and antioxidant capabilities of duck egg white. The fermented feed technology of this invention not only improves the composition of egg white but also achieves a synergistic enhancement of the natural antibacterial and antioxidant properties of egg white.

[0045] Table 2. Evaluation of antibacterial and antioxidant capacity of duck egg whites from different groups

[0046] Note: Different lowercase letters indicate significant differences between groups (P<0.05); the same letter indicates no significant difference.

Claims

1. A fermented feed for laying ducks, characterized in that, The fermented feed is prepared by a method comprising the following steps: (1) Preparation of fermentation substrate The fermentation substrate comprises the following components in parts by weight: 35-60 parts corn, 15-30 parts soybean meal, 5-15 parts wheat bran, 4-10 parts rice bran, 5-9 parts puffed flaxseed, 2-6 parts grape seed meal, 1-4 parts moringa flavonoid powder, 0.5-2.5 parts dicalcium phosphate, 0.5-3 parts limestone powder, 0.1-0.5 parts salt, and 0.1-0.8 parts compound premix. (2) Two-stage fermentation of the fermentation substrate. First stage: Inoculate the fermentation substrate with Bacillus bacteria for aerobic fermentation; Second stage: Inoculate lactic acid bacteria into the material after the first stage of fermentation and add chitosan oligosaccharide for anaerobic fermentation.

2. The fermented feed according to claim 1, characterized in that, The Bacillus is selected from one or more of Bacillus amyloliquefaciens, Bacillus licheniformis, and Bacillus subtilis; the lactic acid bacteria is selected from one or more of Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus casei, Pediococcus pentosaceus, and Bifidobacterium.

3. The fermented feed according to claim 2, characterized in that, The Bacillus species is a combination of Bacillus amyloliquefaciens and Bacillus licheniformis; the lactic acid bacteria is a combination of Lactobacillus plantarum and Pediococcus pentosaceus.

4. The fermented feed according to claim 1, characterized in that, The inoculation amount of Bacillus is 0.1-0.5% of the weight of the fermentation substrate; the inoculation amount of Lactic Acid Bacteria is 0.1-0.5% of the weight of the fermentation substrate; and the amount of Chitosan oligosaccharide is 0.03-0.2% of the weight of the fermentation substrate.

5. The fermented feed according to claim 1, characterized in that, The fermentation conditions for the first stage are: moisture content 30-40%, temperature 35-40℃, fermentation time 12-24 h, and intermittent ventilation. The fermentation conditions for the second stage are: temperature 30-35℃, and closed fermentation for 24-48 h.

6. The fermented feed according to claim 1, characterized in that, The fermentation substrate comprises the following components in parts by weight: 42-50 parts corn, 18-25 parts soybean meal, 6-12 parts wheat bran, 6-10 parts rice bran, 6-8 parts puffed flaxseed, 3-5 parts grape seed meal, 2-3 parts moringa flavonoid powder, 1-2 parts dicalcium phosphate, 0.7-1.5 parts limestone powder, 0.3-0.5 parts salt, and 0.2-0.6 parts compound premix.

7. The use of the fermented feed according to any one of claims 1-6 in improving the natural antibacterial and antioxidant properties of duck eggs.

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