Intestinal tract health-care probiotic pig feed and preparation method thereof

Abstract

The invention belongs to the field of feed chemistry and bioengineering, and discloses an intestinal tract health-care probiotic pig feed and a preparation method thereof. The feed is prepared by taking chitosan which is condensed and modified by food-grade lactic acid oligomers and sodium 2, 3-dihydroxybutyrate as main components, and matching bacillus licheniformis, pediococcus acidilactici, bifidobacterium and beer yeast. The modified chitosan forms a compact carrier membrane through molecular condensation, so that the damage of gastric acid and cholate can be effectively resisted, and the survival rate of probiotics in intestinal tracts is increased; the 2, 3-sodium dihydroxybutyrate is metabolized in intestinal tracts to generate butyrate, so that the synthesis of short-chain fatty acid is promoted, the energy metabolism of epithelial cells is enhanced, and the intestinal mucosal barrier is repaired. The feed provided by the invention has high stability and good biological activity, and can effectively improve intestinal flora balance and nutrient absorption function of pigs.

Description

Technical Field

[0001] This invention belongs to the field of feed chemistry and bioengineering technology, specifically relating to a gut health-promoting probiotic pig feed and its preparation method. Background Technology

[0002] With the rapid development of intensive pig farming, intestinal health problems in pigs have become increasingly prominent, manifesting as digestive and absorptive dysfunction, damage to the intestinal mucosal barrier, and proliferation of harmful bacteria. Traditional feeds often rely on antibiotics, chemical growth promoters, or single probiotic preparations to maintain intestinal balance, but these methods have significant shortcomings. On the one hand, long-term use of antibiotics can easily lead to the development of drug-resistant strains, disrupting the animal's gut microbiota balance and posing a risk of drug residues. On the other hand, single probiotics have poor stability under high temperature and humidity conditions and are easily inactivated by gastric acid and bile salts after entering the intestines, resulting in a significant reduction in biological activity and limited health benefits.

[0003] In recent years, researchers have attempted to utilize natural polysaccharide materials as probiotic carriers to improve their stability and survival rate. Chitosan has attracted widespread attention due to its good biocompatibility and biodegradability; however, its poor solubility in acidic environments and limited binding affinity to probiotics make it difficult to achieve effective protection and sustained release of the bacteria. Existing chitosan modification methods mostly employ chemical cross-linking or synthetic monomer grafting, and the reaction systems often contain organic solvents or toxic condensing agents, limiting its application in the feed and food industries.

[0004] Meanwhile, numerous studies have shown that the gut health of pigs depends not only on the number of probiotics but also on the synthesis and balance of short-chain fatty acids. In particular, butyrate formation plays a crucial role in maintaining energy supply to intestinal epithelial cells, promoting intestinal mucosal repair, and enhancing barrier function. However, existing feed systems lack natural metabolic regulators that can safely and effectively promote butyrate synthesis.

[0005] Therefore, developing a safe, non-toxic probiotic pig feed that can stably carry probiotics and promote the synthesis of short-chain fatty acids is of great significance for improving the intestinal health of pigs, increasing feed utilization, and promoting green farming. Summary of the Invention

[0006] To overcome the problems of low probiotic activity, poor carrier protection, and insufficient intestinal repair capacity in existing feed systems, the present invention aims to provide an intestinal health-promoting probiotic pig feed and its preparation method. This invention uses chitosan modified with food-grade lactic acid oligomers as the probiotic carrier matrix, synergistically introduces sodium 2,3-dihydroxybutyrate as a metabolism promoter, and combines it with various functional probiotics, edible carbon sources, and trace minerals. A compound feed with high stability and bioactivity is obtained through low-temperature granulation or spray drying. This invention forms a safe and efficient intestinal health system that combines probiotic protection, short-chain fatty acid promotion, and intestinal barrier repair functions.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A probiotic pig feed for gut health comprises the following ingredients in parts by weight: 30-60 parts of chitosan modified by food-grade lactic acid oligomer condensation; 5-15 parts of sodium 2,3-dihydroxybutyrate; 3-8 parts of Bacillus licheniformis powder; 2-6 parts of Pediococcus lactis powder; 1-5 parts of Bifidobacterium powder; 1-4 parts of brewer's yeast powder; 10-20 parts of D-glucose; 5-15 parts of trehalose; 0.3-0.8 parts of ferrous sulfate; 0.2-0.5 parts of zinc sulfate; 0.1-0.4 parts of manganese sulfate; 0.03-0.1 parts of copper sulfate; 10-30 parts of corn cob powder; and deionized... 10-30 parts water; wherein the chitosan modified by food-grade lactic acid oligomer condensation is prepared by reacting chitosan and food-grade lactic acid oligomer in a water-soluble dehydration condensation system composed of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide at 45-50°C for 3-5 hours, and then drying after washing with deionized water to remove residual condensing agent; the sodium 2,3-dihydroxybutyrate is an edible organic acid sodium salt, used as a probiotic metabolism promoter, which can promote butyrate synthesis, improve the ratio of short-chain fatty acids in the intestine and enhance the intestinal barrier repair function.

[0009] Optionally, the chitosan modified by food-grade lactic acid oligomer condensation comprises the following raw materials in parts by weight: 80-120 parts chitosan; 20-40 parts food-grade lactic acid oligomer; 2-6 parts citric acid; 1-3 parts glycerol; and 200-300 parts deionized water.

[0010] Optionally, the preparation method of chitosan modified by food-grade lactic acid oligomer condensation includes the following steps:

[0011] (1) Dissolve chitosan in deionized water and stir until a homogeneous and transparent solution is formed;

[0012] (2) Add food-grade lactic acid oligomer, citric acid and glycerol to a homogeneous and transparent solution, so that the carboxyl group of the lactic acid oligomer undergoes a dehydration condensation reaction with the amino group of chitosan under the action of citric acid to generate a chitosan structure grafted with lactic acid oligomer.

[0013] (3) After the reaction is completed, the mixture is naturally cooled to room temperature, washed multiple times with deionized water to remove unreacted components and byproducts, and then dried under vacuum and ground and sieved to obtain chitosan modified by food-grade lactic acid oligomer condensation.

[0014] Optionally, the conditions for step (1) are to stir at 40-50°C until the chitosan is completely dissolved.

[0015] Optionally, the dehydration condensation reaction in step (2) is carried out under stirring conditions at 60-70°C for 3-5 hours.

[0016] Optionally, the conditions for step (3) are vacuum drying at 50-60°C for 8-12 hours and the pH of the washing solution is 6.5-7.0.

[0017] Optionally, a method for preparing a probiotic-based pig feed for gut health includes the following steps:

[0018] S1. Chitosan modified by food-grade lactic acid oligomer condensation is mixed evenly with sodium 2,3-dihydroxybutyrate, D-glucose and trehalose to prepare a probiotic carrier matrix.

[0019] S2, add Bacillus licheniformis powder, Pediococcus lactis powder, Bifidobacterium powder and brewer's yeast powder to the probiotic carrier matrix, mix and adsorb under stirring conditions to obtain a mixture, so that the probiotics are uniformly loaded on the carrier surface;

[0020] S3. Add ferrous sulfate, zinc sulfate, manganese sulfate, copper sulfate and corn cob powder to the mixture, and after stirring the wet mixture evenly, adjust the water content of the system to 25% to 35%.

[0021] S4. The wet mixture is subjected to low-temperature granulation and spray drying. After drying, it is sieved to obtain the finished product of intestinal health-promoting probiotic pig feed.

[0022] Optionally, the mixing conditions in step S1 are stirring at 25-35°C for 10-20 minutes until a uniform carrier matrix is ​​formed; the mixing and adsorption conditions in step S2 are stirring at 20-30°C for 15-30 minutes and maintaining a relative humidity of 50%-60% to prevent the probiotics from becoming inactive.

[0023] Optionally, the stirring conditions in step S3 are: stirring at 25–40°C for 20–40 min, and the water content of the system is controlled at 25%–35%.

[0024] Optionally, the processing conditions for step S4 are: granulation temperature of 40-50°C, spray drying inlet air temperature of 50-60°C, and outlet air temperature of 35-45°C.

[0025] The beneficial effects of this invention are:

[0026] This invention utilizes chitosan modified by food-grade lactic acid oligomer condensation, which significantly improves the water solubility of chitosan and its binding ability to the cell wall of probiotics, forming a stable carrier membrane layer and effectively preventing the inactivation of probiotics in the gastric acid and bile salt environment. Sodium 2,3-dihydroxybutyrate, as an innovative metabolism-promoting component, can be converted into butyrate in the intestine, increasing the proportion of short-chain fatty acids, promoting energy metabolism and mucosal repair of epithelial cells, thereby achieving highly active delivery of probiotics and deep regulation of intestinal function. Attached Figure Description

[0027] The invention will now be further described with reference to the accompanying drawings.

[0028] Figure 1 Infrared spectra of chitosan and chitosan modified by condensation with food-grade lactic acid oligomers;

[0029] Figure 2 A comparison chart showing the survival rate test results of probiotics in samples with different ratios;

[0030] Figure 3 A comparison chart of test results for the production of short-chain fatty acids in samples with different ratios;

[0031] Figure 4 Comparison of acid and alkali resistance test results for samples with different ratios of carriers;

[0032] Figure 5 A comparison chart showing the results of intestinal simulated adsorption and retention performance tests for samples with different ratios. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments. However, the present invention is not limited to the following embodiments. Equivalent adjustments made without departing from the spirit and essence of the present invention should also be considered to fall within the protection scope of the present invention.

[0034] Example 1

[0035] The purpose of this embodiment is to verify the enhancing effect of high-content modified chitosan and sodium 2,3-dihydroxybutyrate on the protective effect of probiotics and the intestinal repair ability.

[0036] S1. 120 parts of chitosan were added to 300 parts of deionized water and stirred at 45°C to dissolve, resulting in a homogeneous and transparent solution. 40 parts of food-grade lactic acid oligomers, 6 parts of citric acid, and 3 parts of glycerol were added, and the mixture was stirred at 65°C for 5 hours to allow the carboxyl groups of the lactic acid oligomers to undergo a dehydration condensation reaction with the amino groups of chitosan under the action of citric acid. After the reaction was completed, the mixture was cooled to room temperature, washed four times with deionized water until the solution pH reached 6.8, vacuum dried at 55°C for 10 hours, and ground through a 100-mesh sieve to obtain chitosan modified by the condensation of food-grade lactic acid oligomers.

[0037] S2, take 60 parts of modified chitosan, 15 parts of sodium 2,3-dihydroxybutyrate, 20 parts of D-glucose and 15 parts of trehalose, stir at 30℃ for 15 minutes to obtain the carrier matrix; add 8 parts of Bacillus licheniformis powder, 6 parts of Pediococcus lactis powder, 5 parts of Bifidobacterium powder and 4 parts of brewer's yeast powder, stir at 25℃ and 55% humidity for 25 minutes to make the probiotics uniformly adsorbed on the carrier surface;

[0038] S3. Add 0.8 parts ferrous sulfate, 0.5 parts zinc sulfate, 0.4 parts manganese sulfate, 0.1 parts copper sulfate, and 30 parts corn cob powder to the mixture, stir for 30 minutes, and control the moisture content of the system to 35%. Perform low-temperature granulation at 45℃, spray drying with an inlet air temperature of 60℃ and an outlet air temperature of 40℃, and pass through a 100-mesh sieve after drying to obtain intestinal health-promoting probiotic pig feed.

[0039] Example 2

[0040] The purpose of this embodiment is to verify the comprehensive balance between the retention rate of probiotic activity and the ability to generate short-chain fatty acids in a feed system with a medium component ratio.

[0041] S1. Add 100 parts of chitosan to 250 parts of deionized water and stir to dissolve at 45°C. Add 30 parts of food-grade lactic acid oligomer, 4 parts of citric acid and 2 parts of glycerol, and stir to react at 65°C for 4 hours. After the reaction is completed, cool to room temperature, wash with deionized water 4 times until the pH is 6.7, vacuum dry at 55°C for 9 hours, grind and pass through a 100-mesh sieve to obtain chitosan modified by condensation of food-grade lactic acid oligomer. Figure 1Infrared spectral comparison results show that the chitosan sample modified by condensation with food-grade lactic acid oligomers exhibits a significant C=O stretching vibration peak at 1735 cm⁻¹, indicating that the carboxyl groups in the lactic acid oligomers have undergone esterification or amidation reactions with the amino groups in chitosan. New C–O–C stretching absorption peaks at 1260 cm⁻¹ and 1215 cm⁻¹ further confirm the formation of lactic ester bonds. The enhanced amide I band at 1650 cm⁻¹ indicates a successful grafting reaction. The weakened intensity of the broad peak at 3420 cm⁻¹ reflects the participation of some hydroxyl and amino groups in the condensation, resulting in a reduction in the number of hydrogen bonds. The overall spectrum shows the introduction of new carboxyl esters and amide bonds into the modified structure, confirming that the lactic acid oligomers have been successfully grafted onto the chitosan molecular chain.

[0042] S2, mix 45 parts of modified chitosan, 10 parts of sodium 2,3-dihydroxybutyrate, 15 parts of D-glucose and 10 parts of trehalose evenly, and stir at 30°C for 15 minutes to form a carrier matrix; add 5 parts of Bacillus licheniformis powder, 4 parts of Pediococcus lactis powder, 3 parts of Bifidobacterium powder and 2.5 parts of brewer's yeast powder, and stir at 25°C and 55% humidity for 20 minutes to fully load the probiotics onto the carrier surface;

[0043] S3. Add 0.5 parts ferrous sulfate, 0.35 parts zinc sulfate, 0.25 parts manganese sulfate, 0.05 parts copper sulfate, and 20 parts corn cob powder to the mixture, stir for 25 minutes, and control the moisture content of the system to 30%; perform low-temperature granulation at 45℃, spray drying with an inlet air temperature of 55℃ and an outlet air temperature of 40℃, and sieve after drying to obtain intestinal health-promoting probiotic pig feed.

[0044] Example 3

[0045] The purpose of this embodiment is to verify the minimum effective level of the feed system in maintaining probiotic activity and intestinal barrier repair under conditions of low content of modified chitosan and metabolism promoter.

[0046] S1. Add 80 parts of chitosan to 200 parts of deionized water and stir to dissolve at 40°C. Add 20 parts of food-grade lactic acid oligomer, 2 parts of citric acid and 1 part of glycerol, and stir to react at 60°C for 3 hours. After the reaction is completed, cool to room temperature, wash 3 times with deionized water until the pH is 6.5, vacuum dry at 50°C for 8 hours, grind and pass through a 100-mesh sieve to obtain chitosan modified by condensation of food-grade lactic acid oligomer.

[0047] S2, mix 30 parts of modified chitosan, 5 parts of sodium 2,3-dihydroxybutyrate, 10 parts of D-glucose and 5 parts of trehalose, and stir at 25°C for 10 minutes to form a carrier matrix; add 3 parts of Bacillus licheniformis powder, 2 parts of Pediococcus lactis powder, 1 part of Bifidobacterium powder and 1 part of brewer's yeast powder, and stir at 20°C and 50% humidity for 15 minutes to obtain a probiotic mixture;

[0048] S3. Add 0.3 parts ferrous sulfate, 0.2 parts zinc sulfate, 0.1 parts manganese sulfate, 0.03 parts copper sulfate, and 10 parts corn cob powder to the mixture, stir for 20 minutes, and control the moisture content of the system to 25%; perform low-temperature granulation at 40℃, spray drying with an inlet air temperature of 50℃ and an outlet air temperature of 35℃, and sieve after drying to obtain intestinal health-promoting probiotic pig feed.

[0049] Comparative Example 1

[0050] The purpose of this comparative study is to verify the changes in the retention rate of probiotic activity and intestinal regulation performance in the feed system when only chitosan is used for single modification.

[0051] S1. Add 100 parts of chitosan to 250 parts of deionized water and stir to dissolve at 45°C. Add 4 parts of citric acid and 2 parts of glycerol and stir to react at 65°C for 4 hours. After the reaction is completed, cool to room temperature, wash 4 times with deionized water until the pH is 6.7, vacuum dry at 55°C for 9 hours, grind through a 100-mesh sieve to obtain chitosan modified by citric acid condensation.

[0052] S2, mix 45 parts of modified chitosan, 10 parts of sodium 2,3-dihydroxybutyrate, 15 parts of D-glucose and 10 parts of trehalose evenly, and stir at 30°C for 15 minutes to form a carrier matrix; add 5 parts of Bacillus licheniformis powder, 4 parts of Pediococcus lactis powder, 3 parts of Bifidobacterium powder and 2.5 parts of brewer's yeast powder, and stir at 25°C and 55% humidity for 20 minutes to allow probiotics to adsorb onto the carrier surface;

[0053] S3. Add 0.5 parts ferrous sulfate, 0.35 parts zinc sulfate, 0.25 parts manganese sulfate, 0.05 parts copper sulfate, and 20 parts corn cob powder to the mixture, stir for 25 minutes, and control the moisture content of the system to 30%; perform low-temperature granulation at 45℃, spray drying with an inlet air temperature of 55℃ and an outlet air temperature of 40℃, and sieve after drying to obtain probiotic pig feed.

[0054] Comparative Example 2

[0055] The purpose of this comparative study is to verify the changes in the protective performance of modified chitosan against probiotics when only food-grade lactic acid oligomers are used for modification without the use of synergistic condensing agents.

[0056] S1. Add 100 parts of chitosan to 250 parts of deionized water and stir to dissolve at 45°C; add 30 parts of food-grade lactic acid oligomer and stir to react for 4 hours at 65°C without adding citric acid or glycerol; after the reaction is completed, cool and wash with deionized water 4 times until the pH is 6.7; vacuum dry at 55°C for 9 hours; grind and pass through a 100-mesh sieve to obtain lactic acid oligomer physically adsorbed chitosan.

[0057] S2, mix 45 parts of chitosan, 10 parts of sodium 2,3-dihydroxybutyrate, 15 parts of D-glucose and 10 parts of trehalose evenly, and stir at 30°C for 15 minutes to form a carrier matrix; add 5 parts of Bacillus licheniformis powder, 4 parts of Pediococcus lactis powder, 3 parts of Bifidobacterium powder and 2.5 parts of brewer's yeast powder, and stir at 25°C and 55% humidity for 20 minutes to allow probiotics to adsorb onto the carrier surface;

[0058] S3. Add 0.5 parts ferrous sulfate, 0.35 parts zinc sulfate, 0.25 parts manganese sulfate, 0.05 parts copper sulfate, and 20 parts corn cob powder to the mixture, stir for 25 minutes, and control the moisture content of the system to 30%; perform low-temperature granulation at 45℃, spray drying with an inlet air temperature of 55℃ and an outlet air temperature of 40℃, and sieve after drying to obtain probiotic pig feed.

[0059] Comparative Example 3

[0060] The purpose of this comparative study is to verify the effect of removing sodium 2,3-dihydroxybutyrate from the feed formulation on the production of short-chain fatty acids and the repair of the intestinal barrier.

[0061] S1. Add 100 parts of chitosan to 250 parts of deionized water and stir to dissolve at 45°C. Add 30 parts of food-grade lactic acid oligomer, 4 parts of citric acid and 2 parts of glycerol, and stir to react at 65°C for 4 hours. After the reaction is completed, cool to room temperature, wash with deionized water 4 times until the pH is 6.7, vacuum dry at 55°C for 9 hours, grind and pass through a 100-mesh sieve to obtain chitosan modified by condensation of food-grade lactic acid oligomer.

[0062] S2, mix 45 parts of modified chitosan, 15 parts of D-glucose and 10 parts of trehalose evenly, and stir at 30°C for 15 minutes to form a carrier matrix; add 5 parts of Bacillus licheniformis powder, 4 parts of Pediococcus lactis powder, 3 parts of Bifidobacterium powder and 2.5 parts of brewer's yeast powder, and stir at 25°C and 55% humidity for 20 minutes to allow probiotics to be adsorbed onto the carrier surface;

[0063] S3. Add 0.5 parts ferrous sulfate, 0.35 parts zinc sulfate, 0.25 parts manganese sulfate, 0.05 parts copper sulfate, and 20 parts corn cob powder to the mixture, stir for 25 minutes, and control the moisture content of the system to 30%; perform low-temperature granulation at 45℃, spray drying with an inlet air temperature of 55℃ and an outlet air temperature of 40℃, and sieve after drying to obtain probiotic pig feed.

[0064] Performance testing

[0065] 1. Probiotic survival rate test

[0066] This test was used to evaluate the ability of different samples to maintain probiotic activity in a simulated gastrointestinal environment. 10 grams each of the samples prepared in Examples 1-3 and Comparative Examples 1-3 were added to 0.1 mol / L hydrochloric acid solution (pH 2.0) and incubated at 37°C with shaking for 1 hour to simulate the gastric fluid environment. The supernatant was then discarded by centrifugation, and the precipitate was transferred to simulated intestinal fluid at pH 7.4. The mixture was then incubated at 37°C with shaking for another 2 hours to simulate the intestinal fluid environment. After dilution, the samples were inoculated onto MRS or LB solid medium plates and incubated at 37°C for 48 hours. The number of colonies was then counted. The survival ability of probiotics in the simulated gastrointestinal environment can be directly assessed based on changes in colony count.

[0067] 2. Short-chain fatty acid production test

[0068] This test was used to detect the metabolic activity of probiotics under simulated intestinal fermentation conditions. One gram of each sample was added to 100 ml of simulated colonic fermentation broth, which consisted of trypsin, yeast extract, glucose, and sodium bicarbonate. The mixture was incubated anaerobically at 37°C for 24 hours. After incubation, the supernatant was collected, filtered to remove impurities, and the concentrations of acetic acid, propionic acid, and butyric acid were determined using gas chromatography. Comparing the short-chain fatty acid content generated by different samples reflects their ability to promote probiotic metabolism and improve the intestinal environment.

[0069] 3. Acid and alkali resistance stability test of the carrier

[0070] This test was used to investigate the structural stability of the modified chitosan-2,3-dihydroxybutyrate sodium composite carrier under different pH conditions. One gram of sample was weighed and added to buffer solutions at pH 2.0, pH 7.0, and pH 8.5, respectively, and shaken at 37°C for 2 hours. The sample was then removed, blotted dry with filter paper, weighed wet, and dried at 60°C to constant weight. The swelling and structural integrity in acidic and alkaline environments were evaluated by observing the volume changes and appearance differences of the samples, thereby determining the protective performance of the carrier against probiotics.

[0071] 4. Intestinal Simulation Adsorption and Retention Performance Test

[0072] This test was used to evaluate the adhesion and retention properties of samples on the intestinal mucosa. Porcine small intestine tissue samples approximately 10 cm in length were selected and kept viable in phosphate-buffered saline (PBSS) at 37°C. A sample suspension containing probiotics (10 g / L solids) was added to the system, and the mixture was gently incubated for 30 minutes. After incubation, the tissue was washed three times with PBSS to remove unattached bacteria, then the tissue homogenate was diluted and inoculated onto plates for culture. By comparing the number of probiotics attached to the tissue surface for each sample, the effectiveness of different systems in promoting probiotic colonization and prolonging intestinal retention time could be evaluated.

[0073] Table 1. Performance test results of probiotic-based pig feed for gut health.

[0074] Sample number Probiotic survival rate (%) Short-chain fatty acid production (mmol / L) Carrier residual rate (%) Probiotic adhesion rate (%) Example 1 86.4 14.2 93.5 72.1 Example 2 92.8 17.6 96.8 79.3 Example 3 88.7 15.9 95.1 75.6 Comparative Example 1 68.2 9.4 84.7 51.3 Comparative Example 2 71.5 10.8 86.2 55.8 Comparative Example 3 73.0 11.3 87.5 57.4

[0075] This invention, through performance testing and comparison of Examples 1 to 3 and Comparative Examples 1 to 3, systematically verified the comprehensive performance of the synergistic system of chitosan modified by food-grade lactic acid oligomer condensation and sodium 2,3-dihydroxybutyrate in terms of probiotic protection, metabolism promotion, structural stability, and intestinal colonization. Test results show that the system of this invention exhibits significant advantages in maintaining probiotic activity, generating short-chain fatty acids, and ensuring carrier stability. Example 2 demonstrated the best overall performance, reflecting the synergistic innovation effect of the structural design.

[0076] According to the data in Table 1, the survival rate of probiotics was significantly improved. Figure 2 Examples 1 to 3 were all superior to the comparative sample, indicating that the modified chitosan matrix can effectively improve the survival ability of probiotics in the gastric acid and bile salt environment. The survival rate of Example 2 reached 92.8%, which was significantly higher than the 68.2% of Comparative Example 1. This indicates that the chitosan after lactic acid oligomer condensation forms a dense molecular protective layer, which can block hydrogen ion penetration, reduce the damage of gastric acid to the bacteria, and thus effectively improve the activity retention rate of probiotics after passing through the gastrointestinal tract.

[0077] The ability to generate short-chain fatty acids is significantly enhanced. Figure 3 The total short-chain fatty acid production in Example 2 was 17.6 mmol / L, representing an increase of approximately 24% and 11% compared to Examples 1 and 3, respectively, and an average increase of nearly 80% compared to the comparative example. This result indicates that sodium 2,3-dihydroxybutyrate can act as a metabolic substrate during fermentation, participating in the butyrate synthesis pathway, promoting the metabolic activity of beneficial intestinal bacteria, increasing the ratio of acetic acid, propionic acid, and butyrate, and thus improving intestinal energy metabolism and gut microbiota homeostasis.

[0078] The structural stability of the carrier is significantly improved. Figure 4 The carrier residual rates of the samples in the examples were all above 93%, with Example 2 showing the highest at 96.8%, significantly better than Comparative Example 1's 84.7%. This result indicates that the chemical condensation between the lactic acid oligomer and chitosan enables the carrier structure to form a cross-linked network, improving the system's acid and alkali resistance and mechanical strength. This structure maintains morphological stability in the variable pH environment of the gut, providing continuous protection and sustained-release support for probiotics.

[0079] Intestinal adhesion performance is significantly optimized. Figure 5The probiotic adhesion rate in Example 2 reached 79.3%, higher than 72.1% in Example 1 and 75.6% in Example 3, and far superior to the comparative range of 51.3% to 57.4%. This indicates that the amino and carboxyl groups on the surface of modified chitosan can form multi-point hydrogen bonds with glycoproteins in the intestinal mucosa, improving the binding strength between probiotics and the intestinal wall; at the same time, butyric acid, generated by the metabolism of sodium 2,3-dihydroxybutyrate in the intestine, can promote epithelial repair and mucus secretion, thereby enhancing the retention stability of probiotics on the intestinal mucosal surface.

[0080] In summary, Example 2 demonstrated the best performance in all four indicators: probiotic activity retention rate, short-chain fatty acid production, carrier stability, and adhesion performance. These results fully demonstrate that the "lactic acid oligomer condensation modified chitosan-2,3-dihydroxybutyrate sodium" synergistic system constructed in this invention not only enhances the survival stability of probiotics but also promotes metabolism and mucosal colonization, achieving a synergistic and innovative effect of intestinal function regulation and microecological optimization.

Claims

1. A probiotic pig feed for gut health, characterized in that, The product contains the following ingredients in parts by weight: 30-60 parts of chitosan modified with food-grade lactic acid oligomers; 5-15 parts of sodium 2,3-dihydroxybutyrate; 3-8 parts of Bacillus licheniformis powder; 2-6 parts of Pediococcus lactis powder; 1-5 parts of Bifidobacterium powder; 1-4 parts of brewer's yeast powder; 10-20 parts of D-glucose; 5-15 parts of trehalose; 0.3-0.8 parts of ferrous sulfate; 0.2-0.5 parts of zinc sulfate; 0.1-0.4 parts of manganese sulfate; 0.03-0.1 parts of copper sulfate; 10-30 parts of corn cob powder; and 10-30 parts of deionized water. The chitosan modified by food-grade lactic acid oligomer condensation is prepared by reacting chitosan and food-grade lactic acid oligomer in a water-soluble dehydration condensation system composed of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide at 45-50°C for 3-5 hours, and then drying after washing with deionized water to remove residual condensing agent; the sodium 2,3-dihydroxybutyrate is an edible organic acid sodium salt, used as a probiotic metabolism promoter, which can promote butyrate synthesis, improve the ratio of short-chain fatty acids in the intestine, and enhance the intestinal barrier repair function.

2. The intestinal health-promoting probiotic pig feed according to claim 1, characterized in that, The chitosan modified by condensation of food-grade lactic acid oligomers comprises the following raw materials in parts by weight: 80-120 parts chitosan; 20-40 parts food-grade lactic acid oligomers; 2-6 parts citric acid; 1-3 parts glycerol; and 200-300 parts deionized water.

3. A probiotic pig feed for intestinal health as described in claim 1 or 2, characterized in that, The preparation method of the chitosan modified by food-grade lactic acid oligomer condensation includes the following steps: (1) Dissolve chitosan in deionized water and stir until a homogeneous and transparent solution is formed; (2) Food-grade lactic acid oligomer, citric acid and glycerol are added to a homogeneous and transparent solution, and a dehydration condensation reaction occurs to generate a chitosan structure grafted with lactic acid oligomer. (3) After the reaction is completed, the mixture is naturally cooled to room temperature, washed multiple times with deionized water, dried under vacuum, ground and sieved to obtain chitosan modified by food-grade lactic acid oligomer condensation.

4. The intestinal health-promoting probiotic pig feed according to claim 3, characterized in that, The condition for step (1) is to stir at 40-50°C until the chitosan is completely dissolved.

5. The intestinal health-promoting probiotic pig feed according to claim 3, characterized in that, The dehydration condensation reaction conditions in step (2) are to stir the reaction at 60-70°C for 3-5 hours.

6. The intestinal health-promoting probiotic pig feed according to claim 3, characterized in that, The conditions for step (3) are vacuum drying at 50-60°C for 8-12 hours and the pH value of the washing solution is 6.5-7.

0.

7. A method for preparing a probiotic-based pig feed for gut health, the probiotic-based pig feed for gut health as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Chitosan modified by food-grade lactic acid oligomer condensation is mixed evenly with sodium 2,3-dihydroxybutyrate, D-glucose and trehalose to prepare a probiotic carrier matrix. S2, Bacillus licheniformis powder, Pediococcus lactis powder, Bifidobacterium powder and brewer's yeast powder are added to the probiotic carrier matrix and mixed and adsorbed under stirring conditions to obtain a mixture; S3, ferrous sulfate, zinc sulfate, manganese sulfate, copper sulfate and corn cob powder are added to the mixture to obtain a wet mixture; S4. The wet mixture is subjected to low-temperature granulation and spray drying. After drying, it is sieved to obtain the finished product of intestinal health-promoting probiotic pig feed.

8. The method for preparing a probiotic pig feed for intestinal health as described in claim 7, characterized in that, The mixing conditions for step S1 are stirring at 25–35°C for 10–20 min until a uniform carrier matrix is ​​formed; the mixing and adsorption conditions for step S2 are stirring at 20–30°C for 15–30 min while maintaining a relative humidity of 50%–60%.

9. The method for preparing a probiotic pig feed for intestinal health according to claim 7, characterized in that, The stirring conditions for step S3 are: stirring at 25-40°C for 20-40 minutes, and controlling the water content of the system at 25%-35%.

10. The method for preparing a probiotic pig feed for intestinal health according to claim 7, characterized in that, The processing conditions for step S4 are: granulation temperature of 40-50℃, spray drying inlet air temperature of 50-60℃, and outlet air temperature of 35-45℃.

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