A growth promoting feed for finishing pigs and a method of preparing the same

Abstract

The present application relates to the technical field of feed, especially to a growth-promoting feed for fattening pigs and a preparation method thereof, which comprises the following raw materials in parts by weight: corn, wheat bran, soybean meal, rapeseed meal, fish meal, modified hydrotalcite, compound enzyme preparation, probiotic preparation, calcium hydrogen phosphate, stone powder, salt, zinc oxide, copper sulfate pentahydrate, soybean oil, choline chloride, mildew inhibitor and antioxidant. The modified hydrotalcite, compound enzyme preparation and probiotic preparation are used in combination, which can significantly improve the growth performance of fattening pigs, reduce the diarrhea rate, improve the nutrient digestibility and improve the serum metabolic indicators.

Description

Technical Field

[0001] This invention relates to the field of feed technology, and in particular to a growth-promoting feed for fattening pigs and its preparation method. Background Technology

[0002] Fattening pig farming is a core link in the pig industry, and its efficiency directly determines the economic benefits of the farmers. Feed, as the nutritional source for the growth and development of fattening pigs, is a key factor affecting daily weight gain, feed conversion ratio (FCR), and farming costs. Currently, the pig farming industry is generally facing deep losses, and both large-scale enterprises and small-scale farmers are focusing on cost reduction and efficiency improvement. Optimizing fattening pig feed formulations and improving feed utilization efficiency are important paths to achieving this. Currently, most growth-promoting feeds for fattening pigs on the market are based on a corn-soybean meal formula. While the raw materials are readily available and the cost is relatively controllable, there are many technical challenges in practical application, making it difficult to meet the needs of modern high-efficiency fattening pig farming. On the one hand, traditional formulas have an imbalance in the energy-protein ratio. The high starch content in corn will increase the gluconeogenesis burden on the liver of fattening pigs in the later stages. The amino acid composition of soybean meal protein does not match the muscle deposition pattern of fattening pigs, resulting in a large amount of nitrogen being converted into urea and excreted, and a surge in metabolic energy consumption. At the same time, anti-nutritional factors such as non-starch polysaccharides in corn and trypsin inhibitors in soybean meal will cause chronic intestinal inflammation, reduce the nutrient absorption area and absorption efficiency, and ultimately lead to a high feed conversion ratio and difficulty in controlling breeding costs.

[0003] The invention patent with publication number CN1826944A discloses a loaded elemental sulfur feed additive and its preparation method. It loads elemental sulfur onto hydrotalcite and utilizes the nanoporous structure of hydrotalcite as a "microreactor". It has the advantages of high bactericidal and disinfection efficacy, improves the absorption and utilization rate of sulfur, and protects the intestinal mucosa from the invasion of pathogens.

[0004] However, while elemental sulfur has some bactericidal effects, there is a strict threshold for sulfur metabolism in the body, and excessive intake can cause physiological burden. On the one hand, excessive sulfur can be converted into sulfides in the intestines, altering the intestinal environment, inhibiting the activity of beneficial bacteria such as lactic acid bacteria and bifidobacteria, and disrupting the balance of the gut microbiota. On the other hand, sulfur is mainly metabolized and converted by the liver and excreted by the kidneys; excessive addition will far exceed the liver's metabolic capacity, leading to sulfur accumulation in the body. This accumulation directly stimulates the digestive tract, causing stress responses such as diarrhea and vomiting in growing pigs, and increases intestinal mucosal permeability, facilitating the invasion of pathogens. At the same time, the increased cortisol secretion caused by stress will further suppress appetite and digestive function, ultimately resulting in a significant decline in growth performance. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides a growth-promoting feed for fattening pigs and a method for preparing the same.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A growth-promoting feed for fattening pigs, characterized in that, by weight, it comprises the following raw materials: 600-650 parts corn, 40-60 parts wheat bran, 200-240 parts soybean meal, 20-40 parts rapeseed meal, 10-20 parts fish meal, 0.5-2.0 parts modified hydrotalcite, 0.05-0.2 parts compound enzyme preparation, 0.05-0.2 parts probiotic preparation, 10-15 parts dicalcium phosphate, 5-10 parts limestone powder, 3-4 parts salt, 0.1-0.2 parts zinc oxide, 0.01-0.03 parts copper sulfate pentahydrate, 15-25 parts soybean oil, 0.5-1.5 parts choline chloride, 0.2-0.8 parts antifungal agent, and 0.01-0.05 parts antioxidant; Among them, the modified hydrotalcite is a functionalized hydrotalcite obtained by modifying magnesium aluminum hydrotalcite with a silane coupling agent and then grafting it with methacrylamide and 2-vinylpyridine. The particle size of the magnesium aluminum hydrotalcite is 50-200nm.

[0007] Furthermore, the modified hydrotalcite is prepared by the following steps: S1. After drying the magnesium aluminum hydrotalcite, disperse it in N,N-dimethylformamide, add vinyltriethoxysilane and reflux to obtain vinyl-functionalized magnesium aluminum hydrotalcite; S2. The vinyl-functionalized magnesium aluminum hydrotalcite obtained in step S1 is dispersed in N,N-dimethylformamide, methacrylamide, 2-vinylpyridine and an initiator are added, and a graft copolymerization reaction is carried out under a protective gas atmosphere to obtain modified hydrotalcite.

[0008] Furthermore, the compound enzyme preparation is selected from one or more of xylanase, β-glucanase, cellulase, and phytase, and is in powder form with a moisture content ≤8%; the probiotic preparation is selected from one or more of lactic acid bacteria, Bacillus subtilis, and yeast, and is in powder form with a moisture content ≤6%.

[0009] Furthermore, the antifungal agent is selected from one or more of calcium propionate, sodium diacetate, and potassium sorbate; the antioxidant is selected from one or more of ethoxyquinoline, butylated hydroxyanisole, and butylated hydroxytoluene.

[0010] Further, in step S1, the mass-to-volume ratio of magnesium aluminum hydrotalcite to vinyltriethoxysilane is 1 g: (0.5-0.8) mL, the dropping rate of vinyltriethoxysilane is 1-2 mL / min, and after the dropping is completed, stirring is continued for 30-60 min, and then the temperature is raised to the reflux temperature.

[0011] Further, in step S1, the reflux reaction temperature is 100-120℃ and the time is 20-28h; the drying temperature is 80-100℃ and the drying time is 4-6h; the dispersion concentration of magnesium aluminum hydrotalcite in N,N-dimethylformamide is 50-100g / L, the dispersion method is ultrasonic dispersion, the ultrasonic power is 200-300W, and the ultrasonic time is 30-60min; the reflux reaction is carried out in an oil bath with a stirring rate of 150-200r / min.

[0012] Further, in step S2, the mass ratio of vinyl-functionalized magnesium aluminum hydrotalcite, methacrylamide, and 2-vinylpyridine is 1:(1.5-2.5):(2.5-3.5); the initiator is azobisisobutyronitrile, and its amount is 0.5-1.5% of the total mass of methacrylamide and 2-vinylpyridine. Azobisisobutyronitrile is first dissolved in a small amount of N,N-dimethylformamide, and then slowly added dropwise to the reaction system at a dropping rate of 0.5-1 mL / min. After the addition is complete, the temperature is raised to the reaction temperature.

[0013] Further, in step S2, the graft copolymerization reaction is carried out at a temperature of 65-80℃ for 10-15 hours; the concentration of vinyl-functionalized magnesium aluminum hydrotalcite in N,N-dimethylformamide is 30-50 g / L, and the dispersion method is mechanical stirring at a stirring rate of 120-180 r / min; after the reaction, the modified hydrotalcite is obtained by centrifugation, washing, and drying. The centrifugation speed is 3000-5000 r / min, the centrifugation time is 10-15 min, the washing is performed with anhydrous ethanol 3-5 times, the drying temperature is 70-90℃, and the drying time is 6-8 hours.

[0014] According to another aspect of the present invention, a method for preparing the above-mentioned growth-promoting feed for fattening pigs is provided, comprising the following steps: Weigh each ingredient according to the specified weight proportions, mix them evenly, pulverize them, pass them through a 2.0-3.0mm sieve, and granulate them to a diameter of 3.0-5.0mm and a length of 6-15mm. This yields the growth-promoting feed for fattening pigs. The mixing speed is 180-220r / min, and the mixing time is 15-20min; the pulverizing speed is 2800-3200r / min; the granulation temperature is 70-85℃, and the granulation pressure is 2.5-3.5MPa. After granulation, cool the feed to room temperature (20-25℃) for 30-40min. After cooling, the feed moisture content should be ≤12%. Then, sieve the feed to remove unqualified particles (particles with a diameter deviation of 3.0-5.0mm and a length deviation of 6-15mm). The unqualified particles are returned to the pulverizing step for reprocessing.

[0015] The beneficial effects of this invention are: 1. Modified hydrotalcite uses a silane coupling agent to anchor vinyl groups to the surface of the hydrotalcite layers, and further grafts methacrylamide and 2-vinylpyridine copolymers to form a dense polymer brush shell layer. This creates a physical barrier in space, embedding heat-sensitive ingredients such as complex enzymes and probiotics within its molecular sieve network. In the high-temperature and high-humidity environment of feed pelleting, this structure effectively blocks the direct impact of heat and moisture on enzyme proteins and bacteria, significantly reducing activity loss during processing. Simultaneously, the steric hindrance effect generated by the polymer brush prevents the aggregation of nano-sized hydrotalcite particles, ensuring uniform dispersion of functional ingredients in the feed matrix.

[0016] 2. The grafted 2-vinylpyridine undergoes protonation under gastric pH conditions, imbuing the entire polymer brush with a high-density positive charge. This counteracts the strong adsorption of nutrients and harmful substances. Negatively charged mycotoxins, phytic acid, and bacterial endotoxins in corn-soybean meal diets are efficiently captured and fixed on the surface of the hydrotalcite through electrostatic attraction, and excreted with feces. This reduces the damage of these substances to intestinal epithelial cells and the overactivation of the immune system. Simultaneously, the extended polymer brush segments spatially form a dense protective layer, physically isolating the complex enzyme preparation and probiotics from gastric acid and pepsin, preventing premature inactivation and ensuring that sufficient active ingredients reach their sites of action.

[0017] 3. As the pH of the chyme gradually increases, the pyridine ring deprotonates, and the conformation of the polymer brush changes from an extended state to a contracted or coiled state. The complex enzyme preparation, originally embedded inside the brush layer, is precisely released into the anterior end of the small intestine, maximizing the enzymatic hydrolysis efficiency. The hydrotalcite layer exposed after the polymer brush contracts regains its anion exchange capacity and can continue to adsorb residual anti-nutritional factors in the small intestine.

[0018] 4. The abundant amide groups in the copolymer layer of modified hydrotalcite can form hydrogen bond networks with the glycan chains of mucin in the intestinal mucus layer, helping to prolong the retention time of modified hydrotalcite particles and their carried enzymes and probiotics on the intestinal wall. This mucosal anchoring effect creates a more favorable microenvironment for the competitive colonization of probiotics and also prolongs the hydrolytic reaction window of enzymes in their action area. Simultaneously, the large specific surface area and amphiphilic polymer chains of modified hydrotalcite can participate in the emulsification and dispersion process of soybean oil, and together with choline chloride, participate in the formation of chylomicrons, helping to improve the absorption efficiency of long-chain fatty acids and fat-soluble vitamins. These effects can, to some extent, compensate for the insufficient energy utilization efficiency in traditional corn-soybean meal diets and have a positive significance for improving the energy-protein ratio imbalance. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Unless otherwise specified, all raw materials used in this invention are commercially available products. Specifically, magnesium aluminum hydrotalcite (MgAl) was analytical grade and purchased from Shandong Wanhua Chemical Group Co., Ltd.; N,N-dimethylformamide (DMF) was analytical grade and purchased from Sinopharm Chemical Reagent Co., Ltd.; vinyltriethoxysilane (VTH) with a purity ≥98% was purchased from Nanjing Chenggong Organosilicon Materials Co., Ltd.; methacrylamide (MDMA) with a purity ≥99% was purchased from Aladdin Reagent (Shanghai) Co., Ltd.; 2-vinylpyridine (VTH) with a purity ≥97% was purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; and azobisisobutyronitrile (AI) was also purchased from the manufacturer. BN (analytical grade), purchased from Tianjin Guangfu Fine Chemical Research Institute; corn, wheat bran, soybean meal, rapeseed meal, and fishmeal, feed grade, purchased from COFCO Feed Co., Ltd.; compound enzyme preparation (xylanase, phytase, β-glucanase, cellulase), purchased from Novozymes (China) Biotechnology Co., Ltd.; probiotic preparation (lactic acid bacteria, Bacillus subtilis, yeast), purchased from Angel Yeast Co., Ltd.; dicalcium phosphate, limestone powder, salt, zinc oxide, and copper sulfate pentahydrate, purchased from Guangzhou Tianke Biotechnology Co., Ltd.

[0021] Preparation Example 1 Modified hydrotalcite is prepared by the following steps: S1. Take 100g of magnesium aluminum hydrotalcite with a particle size of 50nm, dry it at 80℃ for 4h, and disperse it in 1000mL of N,N-dimethylformamide (dispersion concentration 50g / L). Use 200W ultrasonic power to ultrasonically disperse it for 30min. Take 50mL of vinyltriethoxysilane and add it to the dispersion at a dropping rate of 1mL / min. After the addition is complete, continue stirring for 30min. Then raise the temperature to 100℃ and use oil bath reflux and stirring rate of 150r / min to reflux for 20h to obtain vinyl functionalized magnesium aluminum hydrotalcite. S2. Take 50g of the vinyl-functionalized magnesium aluminum hydrotalcite obtained in step S1 and disperse it in 1667mL of N,N-dimethylformamide (dispersion concentration 30g / L). Stir and disperse at a stirring rate of 120r / min. Take 75g of methacrylamide and 125g of 2-vinylpyridine and add them to the dispersion. Azobisisobutyronitrile is selected as the initiator. Take 1g of azobisisobutyronitrile, dissolve it in 10mL of N,N-dimethylformamide, and then slowly add it to the reaction system at a dropping rate of 0.5mL / min. After the addition is complete, raise the temperature to 65℃ and react for 10h under a protective gas atmosphere. After the reaction is completed, centrifuge at 3000r / min for 10min, wash three times with anhydrous ethanol (50mL each time), and then dry at 70℃ for 6h to obtain the modified hydrotalcite.

[0022] Preparation Example 2 Modified hydrotalcite is prepared by the following steps: S1. Take 100g of magnesium aluminum hydrotalcite with a particle size of 125nm, dry it at 90℃ for 5h, and disperse it in 1333mL of N,N-dimethylformamide (dispersion concentration 75g / L). Use 250W ultrasonic power to ultrasonically disperse it for 45min. Take 65mL of vinyltriethoxysilane and add it to the dispersion at a dropping rate of 1.5mL / min. After the addition is complete, continue stirring for 45min. Then raise the temperature to 110℃ and use oil bath reflux and stirring rate of 175r / min to reflux for 24h to obtain vinyl functionalized magnesium aluminum hydrotalcite. S2. Take 50g of the vinyl-functionalized magnesium aluminum hydrotalcite obtained in step S1 and disperse it in 1250mL of N,N-dimethylformamide (dispersion concentration 40g / L). Stir and disperse at a stirring rate of 150r / min. Take 100g of methacrylamide and 150g of 2-vinylpyridine and add them to the dispersion. Azobisisobutyronitrile is selected as the initiator. Take 2.5g of azobisisobutyronitrile, dissolve it in 15mL of N,N-dimethylformamide, and then slowly add it to the reaction system at a dropping rate of 0.75mL / min. After the addition is complete, raise the temperature to 72℃ and react for 12.5h under a protective gas atmosphere. After the reaction is completed, centrifuge at 4000r / min for 12.5min, wash with anhydrous ethanol 4 times (50mL each time), and then dry at 80℃ for 7h to obtain the modified hydrotalcite.

[0023] Preparation Example 3 Modified hydrotalcite is prepared by the following steps: S1. Take 100g of magnesium aluminum hydrotalcite with a particle size of 200nm, dry it at 100℃ for 6h, and disperse it in 1000mL of N,N-dimethylformamide (dispersion concentration 100g / L). Use 300W ultrasonic power to ultrasonically disperse it for 60min. Take 80mL of vinyltriethoxysilane and add it to the dispersion at a dropping rate of 2mL / min. After the addition is complete, continue stirring for 60min. Then raise the temperature to 120℃ and use oil bath reflux and stirring rate of 200r / min to reflux for 28h to obtain vinyl functionalized magnesium aluminum hydrotalcite. S2. Take 50g of the vinyl-functionalized magnesium aluminum hydrotalcite obtained in step S1 and disperse it in 1000mL of N,N-dimethylformamide (dispersion concentration 50g / L). Stir and disperse at a stirring rate of 180r / min. Take 125g of methacrylamide and 175g of 2-vinylpyridine and add them to the dispersion. Azobisisobutyronitrile is selected as the initiator. Take 4.5g of azobisisobutyronitrile, dissolve it in 20mL of N,N-dimethylformamide, and then slowly add it to the reaction system at a dropping rate of 1mL / min. After the addition is complete, raise the temperature to 80℃ and react for 15h under a protective gas atmosphere. After the reaction is completed, centrifuge at 5000r / min for 15min, wash with anhydrous ethanol 5 times (50mL each time), and then dry at 90℃ for 8h to obtain the modified hydrotalcite.

[0024] Example 1

[0025] A method for preparing a growth-promoting feed for fattening pigs includes the following steps: Weigh the following raw materials by weight: 600 parts corn, 40 parts wheat bran, 200 parts soybean meal, 20 parts rapeseed meal, 10 parts fish meal, 0.5 parts modified hydrotalcite prepared in Example 1, 0.05 parts compound enzyme preparation, 0.05 parts probiotic preparation, 10 parts dicalcium phosphate, 5 parts limestone powder, 3 parts salt, 0.1 parts zinc oxide, 0.01 parts copper sulfate pentahydrate, 15 parts soybean oil, 0.5 parts choline chloride, 0.2 parts antifungal agent, and 0.01 parts antioxidant. Among them, the compound enzyme preparation uses xylanase (powder, moisture content ≤8%); the probiotic preparation uses lactic acid bacteria (powder, moisture content ≤6%); the antifungal agent uses calcium propionate; and the antioxidant uses ethoxyquinoline. The above raw materials are placed in a mixing device and mixed at 180 r / min for 15 min. After being mixed evenly, the mixture is pulverized at 2800 r / min and passed through a 2.0 mm sieve. The pulverized material is then fed into a pelleting device and pelleted at 70℃ and 2.5 MPa to obtain pellets with a diameter of 3.0 mm and a length of 6 mm. After pelleting, the pellets are cooled to 20℃ for 30 min. The moisture content of the cooled feed is ≤12%, which is the growth-promoting feed for fattening pigs.

[0026] Example 2

[0027] A method for preparing a growth-promoting feed for fattening pigs includes the following steps: Weigh the following raw materials by weight: 625 parts corn, 50 parts wheat bran, 220 parts soybean meal, 30 parts rapeseed meal, 15 parts fish meal, 1.25 parts modified hydrotalcite obtained in Preparation Example 2, 0.125 parts compound enzyme preparation, 0.125 parts probiotic preparation, 12.5 parts dicalcium phosphate, 7.5 parts limestone powder, 3.5 parts salt, 0.15 parts zinc oxide, 0.02 parts copper sulfate pentahydrate, 20 parts soybean oil, 1.0 part choline chloride, 0.5 parts antifungal agent, and 0.03 parts antioxidant. Among them, the compound enzyme preparation uses xylanase and phytase (powder, moisture content ≤8%); the probiotic preparation uses Bacillus subtilis and yeast (powder, moisture content ≤6%); the antifungal agent uses sodium diacetate and potassium sorbate; and the antioxidant uses butylated hydroxyanisole. The above raw materials are placed in a mixing device and mixed at 200 r / min for 17.5 min. After being mixed evenly, the mixture is pulverized at 3000 r / min and passed through a 2.5 mm sieve. The pulverized material is then fed into a pelleting device and pelleted at 77℃ and 3.0 MPa to obtain pellets with a diameter of 4.0 mm and a length of 10.5 mm. After pelleting, the pellets are cooled to 22℃ for 35 min. The moisture content of the cooled feed is ≤12%, which is the growth-promoting feed for fattening pigs.

[0028] Example 3

[0029] A method for preparing a growth-promoting feed for fattening pigs includes the following steps: Weigh the following raw materials by weight: 650 parts corn, 60 parts wheat bran, 240 parts soybean meal, 40 parts rapeseed meal, 20 parts fish meal, 2.0 parts modified hydrotalcite obtained in Preparation Example 3, 0.2 parts compound enzyme preparation, 0.2 parts probiotic preparation, 15 parts dicalcium phosphate, 10 parts limestone powder, 4 parts salt, 0.2 parts zinc oxide, 0.03 parts copper sulfate pentahydrate, 25 parts soybean oil, 1.5 parts choline chloride, 0.8 parts antifungal agent, and 0.05 parts antioxidant. Among them, the compound enzyme preparation uses β-glucanase, cellulase and phytase (powder, moisture content ≤8%); the probiotic preparation uses lactic acid bacteria, Bacillus subtilis and yeast (powder, moisture content ≤6%); the antifungal agent uses calcium propionate, sodium diacetate and potassium sorbate; and the antioxidant uses butylated hydroxytoluene. The above raw materials are placed in a mixing device and mixed at 220 r / min for 20 min. After being mixed evenly, the mixture is pulverized at 3200 r / min and passed through a 3.0 mm sieve. The pulverized material is then fed into a pelleting device and pelleted at 85℃ and 3.5 MPa to obtain pellets with a diameter of 5.0 mm and a length of 15 mm. After pelleting, the pellets are cooled to 25℃ for 40 min. The moisture content of the cooled feed is ≤12%, which is the growth-promoting feed for fattening pigs.

[0030] Example 4

[0031] A method for preparing a growth-promoting feed for fattening pigs includes the following steps: Weigh the following raw materials by weight: 610 parts corn, 45 parts wheat bran, 210 parts soybean meal, 25 parts rapeseed meal, 12 parts fish meal, 0.8 parts modified hydrotalcite prepared in Example 1, 0.08 parts compound enzyme preparation, 0.08 parts probiotic preparation, 11 parts dicalcium phosphate, 6 parts limestone powder, 3.2 parts salt, 0.12 parts zinc oxide, 0.015 parts copper sulfate pentahydrate, 18 parts soybean oil, 0.7 parts choline chloride, 0.3 parts antifungal agent, and 0.02 parts antioxidant. Among them, the compound enzyme preparation uses cellulase and phytase (powder, moisture content ≤8%); the probiotic preparation uses lactic acid bacteria and Bacillus subtilis (powder, moisture content ≤6%); the antifungal agent uses calcium propionate and sodium diacetate; and the antioxidant uses ethoxyquinoline and butylated hydroxyanisole. The above raw materials are placed in a mixing device and mixed at 190 r / min for 16 min. After being mixed evenly, the mixture is pulverized at 2900 r / min and passed through a 2.2 mm sieve. The pulverized material is then fed into a pelleting device and pelleted at 75℃ and 2.8 MPa to obtain pellets with a diameter of 3.5 mm and a length of 8 mm. After pelleting, the pellets are cooled to 21℃ for 32 min. The moisture content of the cooled feed is ≤12%, which is the growth-promoting feed for fattening pigs.

[0032] Example 5

[0033] A method for preparing a growth-promoting feed for fattening pigs includes the following steps: Weigh the following raw materials by weight: 615 parts corn, 48 parts wheat bran, 215 parts soybean meal, 28 parts rapeseed meal, 14 parts fish meal, 1.0 part modified hydrotalcite prepared in Example 2, 0.1 part compound enzyme preparation, 0.1 part probiotic preparation, 12 parts dicalcium phosphate, 7 parts limestone powder, 3.3 parts salt, 0.14 parts zinc oxide, 0.018 parts copper sulfate pentahydrate, 19 parts soybean oil, 0.8 parts choline chloride, 0.4 parts antifungal agent, and 0.025 parts antioxidant. Among them, the compound enzyme preparation uses xylanase and β-glucanase (powder, moisture content ≤8%); the probiotic preparation uses Bacillus subtilis and yeast (powder, moisture content ≤6%); the antifungal agent uses sodium diacetate and potassium sorbate; and the antioxidant uses butylated hydroxyanisole and butylated hydroxytoluene. The above raw materials are placed in a mixing device and mixed at 195 r / min for 17 min. After being mixed evenly, the mixture is pulverized at 2950 r / min and passed through a 2.4 mm sieve. The pulverized material is then fed into a pelleting device and pelleted at 75℃ and 2.9 MPa to obtain pellets with a diameter of 3.8 mm and a length of 9 mm. After pelleting, the pellets are cooled to 21.5℃ for 34 min. The moisture content of the cooled feed is ≤12%. Unqualified pellets are returned to the pulverizing step for reprocessing to obtain growth-promoting feed for fattening pigs.

[0034] Example 6

[0035] A method for preparing a growth-promoting feed for fattening pigs includes the following steps: Weigh the following raw materials by weight: 635 parts corn, 55 parts wheat bran, 230 parts soybean meal, 35 parts rapeseed meal, 18 parts fish meal, 1.8 parts modified hydrotalcite obtained in Preparation Example 3, 0.18 parts compound enzyme preparation, 0.18 parts probiotic preparation, 14 parts dicalcium phosphate, 9 parts limestone powder, 3.8 parts salt, 0.18 parts zinc oxide, 0.028 parts copper sulfate pentahydrate, 23 parts soybean oil, 1.3 parts choline chloride, 0.7 parts antifungal agent, and 0.045 parts antioxidant. Among them, the compound enzyme preparation uses xylanase, cellulase and phytase (powder, moisture content ≤8%); the probiotic preparation uses lactic acid bacteria, Bacillus subtilis and yeast (powder, moisture content ≤6%); the antifungal agent uses calcium propionate, sodium diacetate and potassium sorbate; and the antioxidant uses ethoxyquinoline and butylated hydroxytoluene. The above raw materials are placed in a mixing device and mixed at 210 r / min for 19 min. After being mixed evenly, the mixture is pulverized at 3100 r / min and passed through a 2.8 mm sieve. The pulverized material is then fed into a pelleting device and pelleted at 82℃ and 3.3 MPa to obtain pellets with a diameter of 4.5 mm and a length of 13 mm. After pelleting, the pellets are cooled to 24℃ for 38 min. The moisture content of the cooled feed is ≤12%. Unqualified pellets are returned to the pulverizing step for reprocessing to obtain growth-promoting feed for fattening pigs.

[0036] Comparative Example 1 The difference between this comparative example and Example 1 is that modified hydrotalcite is not added, while the other raw material ratios and preparation steps are the same as in Example 1.

[0037] Comparative Example 2 The difference between this comparative example and Example 1 is that the modified hydrotalcite is replaced with unmodified magnesium aluminum hydrotalcite (particle size 50nm), and the amount is still 0.5 parts. The other raw material ratios and preparation steps are the same as in Example 1.

[0038] Comparative Example 3 The difference between this comparative example and Example 2 is that no compound enzyme preparation is added, while the other raw material ratios and preparation steps are the same as in Example 2.

[0039] Comparative Example 4 The difference between this comparative example and Example 3 is that no probiotic preparation is added, while the other raw material ratios and preparation steps are the same as in Example 3.

[0040] 110 healthy, uniform boar fattening pigs with an initial weight of 30±2 kg were selected. The pigs were required to be in good spirits, have smooth skin and coat, no disease symptoms, normal appetite, and be from the same source and raised under the same background.

[0041] All selected fattening pigs were uniformly numbered (using ear tags, with each pig corresponding to a unique number), and then routine deworming treatment was carried out (using albendazole ivermectin premix, mixed with feed according to the recommended dosage in the instructions, and fed continuously for 3 days); after deworming, according to the routine immunization program for fattening pigs, they were vaccinated against swine fever, porcine reproductive and respiratory syndrome (PRRS), foot-and-mouth disease, etc., and observed for 3 days after vaccination to confirm that there were no adverse reactions to the vaccines.

[0042] All pigs were transferred to experimental pig pens and housed in individual pens (10 pigs per pen, with uniform pen specifications, area, ventilation, and lighting conditions) for a 7-day pre-feeding period. During this period, all pigs were fed a basal diet (without any experimental additives) with free access to feed and water. Pen manure was cleaned daily to keep the pens clean and dry, allowing the pigs to adapt to the experimental environment, feeding management, and feeding method. After the pre-feeding period, pigs exhibiting lethargy, abnormal appetite, or significant weight fluctuations (deviating from initial weight ±2 kg) were culled. If any culled pigs were found, they were replaced from the reserve pigs to ensure the number of pigs in each group remained constant.

[0043] After the pre-feeding period, all pigs were weighed on an empty stomach (in the morning, after fasting for 12 hours and water restriction for 2 hours), and the initial weight of each pig was recorded. The pigs were randomly divided into 11 treatment groups, with 10 pigs in each group, housed in individual pens. There were no significant differences in the initial average weight among the groups (P>0.05), ensuring the rationality of the grouping. The 11 treatment groups were: Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Control Group (corn and soybean meal only). Sufficient experimental feed was prepared in advance according to the formulations and preparation processes of Examples 1-6 and Comparative Examples 1-4.

[0044] The trial period lasted for 60 days, during which all pigs in the treatment group were allowed free access to feed and water. Feed was added at 8:00 a.m. every day, with the amount added ensuring that there was always a small amount of feed left in the trough (about the amount of feed a pig could consume in one hour) to avoid insufficient feed or waste. The troughs were cleaned at 6:00 p.m. every day, the leftover feed was removed, and the weight of the leftover feed was recorded to ensure accurate feed intake statistics.

[0045] Clean the manure in the pens regularly every day (once at 7:30 am and once at 5:30 pm) to keep the pens clean and dry; control the environmental conditions of the pigsty, keep the temperature between 18-25℃, control the relative humidity between 60%-70%, ventilate twice a day for 30-60 minutes each time to ensure fresh air in the pens; use natural light combined with artificial lighting, with a daily light duration of 12-14 hours, avoiding direct sunlight or insufficient light.

[0046] Observe the pigs' mental state, coat condition, feed intake, and fecal form daily. If any abnormalities such as lethargy, loss of appetite, diarrhea, or fever are found, record the abnormal symptoms, the time of occurrence, and the pig's number in a timely manner. Isolate the pig for observation and treat it using routine veterinary methods. Record the medication used during treatment. If a pig's condition is too severe to continue the experiment, remove the pig and do not replace it with a replacement. Note the removal details when compiling statistical data.

[0047] (a) Measurement of growth performance indicators On the first day of the trial period and the 60th day after it ends, each pig was weighed on an empty stomach (12 hours of fasting and 2 hours of water fasting) for two consecutive mornings. The average of the two weighings was taken as the pig's initial weight and final weight. During the trial period, each pig was weighed on an empty stomach once a week at a fixed time (every Monday morning), and the weight data of each pig was recorded to calculate the average daily weight gain.

[0048] Accurately record the amount of feed added (weight of feed added in the morning) and the amount of leftover feed (weight of leftover feed cleaned up in the afternoon) for each pen every day, and calculate the actual feed intake of each pen the previous day (actual feed intake = amount of feed added - amount of leftover feed); summarize the actual feed intake of each pen once a week, and calculate the average daily feed intake of each group based on the number of pigs in each pen.

[0049] Based on body weight and feed intake data, calculate the average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (F / G) for each group of pigs. The calculation formulas are as follows: Average daily weight gain (ADG) = (final weight - initial weight) / number of days in the trial period (60 days); Average daily feed intake (ADFI) = Total feed intake / (Number of pigs × Number of days in the trial period); Feed conversion ratio (F / G) = Average daily feed intake (ADFI) / Average daily gain (ADG).

[0050] The results are shown in Table 1: Table 1. Effects of different treatment groups on growth performance of finishing pigs

[0051] (II) Diarrhea Rate Statistics Observe and record the number of pigs with diarrhea in each pen twice a day, at 9:00 AM and 4:00 PM (diarrhea criteria: watery or loose stools, unformed, passed twice or more consecutively). Count the total number of pigs with diarrhea in each pen daily, and summarize the results weekly to calculate the diarrhea rate for each group. The calculation formula is as follows: Diarrhea rate (%) = (Total number of diarrheal episodes / (Number of pigs × Number of days in the trial period)) × 100%; The total number of diarrheal heads = the sum of the number of diarrheal heads per pen per day (if the same pig has diarrhea multiple times on the same day, it is counted as 1 head).

[0052] The results are shown in Table 2: Table 2. Effects of different treatment groups on diarrhea rate in fattening pigs

[0053] (III) Determination of apparent digestibility of nutrients Starting on day 50 of the trial period, three pigs were randomly selected from each group (each pig was raised separately and marked). Chromium trioxide (Cr2O3) was added evenly to their basal diet at a ratio of 0.3% as an exogenous indicator. After adding the indicator, the pigs were pre-fed for 5 days to ensure that their gastrointestinal tract adapted to the indicator and that the indicator was evenly distributed in their feces.

[0054] After the pre-feeding period, fresh feces were collected from each experimental pig for five consecutive days (collected at fixed times daily to avoid fecal contamination). The collected feces were mixed thoroughly, and approximately 200g was taken as a fecal sample. Immediately, 5mL of 10% hydrochloric acid solution was added for nitrogen fixation treatment, and the sample was frozen for later analysis. Simultaneously, 500g of experimental feed samples were collected from each group, dried, pulverized through a 40-mesh sieve, and sealed for storage. These samples were used to determine the dry matter, crude protein, crude fat, and energy content of the feed.

[0055] Frozen fecal samples were thawed, dried (65℃, dried to constant weight), and pulverized through a 40-mesh sieve. Dry matter (GB / T 6435-2014), crude protein (GB / T 6432-2018), and crude fat (GB / T 6433-2006) in the feces and feed were determined using conventional testing methods. The chromium trioxide content in the feces and feed was also determined using a colorimetric method. Based on the results, the apparent digestibility of each nutrient was calculated using the following formula: Apparent digestibility of nutrients (%) = 1 - (nutrient content in feces / nutrient content in feed) × (Cr2O3 content in feed / Cr2O3 content in feces) × 100%.

[0056] The results are shown in Table 3: Table 3. Effects of different treatment groups on the apparent digestibility of nutrients in finishing pigs.

[0057] (iv) Serum biochemical index determination After weighing at the end of the experiment (day 60), 5 pigs were randomly selected from each group, and 10 mL of blood was collected using the anterior vena cava blood collection method. The blood was injected into centrifuge tubes without anticoagulant and left to stand at room temperature for 2 hours. After the blood coagulated, the blood was centrifuged at 3000 r / min for 15 min to separate the serum. The serum was aliquoted into 2 mL centrifuge tubes, labeled with the group and pig number, and frozen for storage to avoid repeated freeze-thaw cycles.

[0058] The levels of total protein (TP), albumin (ALB), blood urea nitrogen (BUN), glucose (GLU), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) in serum were measured using a fully automated biochemical analyzer, following the instructions of the corresponding reagent kits. Each sample was measured three times, and the average value was taken as the final result. The results are shown in Table 4. Table 4. Effects of different treatment groups on serum biochemical parameters of fattening pigs

[0059] As shown in Table 1, the average daily gain (ADG) of groups 1-6 was significantly higher than that of the comparative and control groups, and the average daily feed intake (ADFI) was also relatively higher, while the feed conversion ratio (F / G) was significantly lower than that of the comparative and control groups. This indicates that the feed formulation using modified hydrotalcite and a reasonable combination of compound enzyme preparations and probiotic preparations can effectively promote the growth of finishing pigs and improve feed conversion efficiency.

[0060] Comparative Examples 1-4 showed better growth performance in all indicators than the control group, but worse than the Example Group. This indicates that the modified hydrotalcite, compound enzyme preparation, and probiotic preparation each have a certain promoting effect on the growth of fattening pigs, but the synergistic effect of the three is better.

[0061] The dense polymer brush shell formed by modified hydrotalcite blocks the direct impact of heat and moisture on enzymes, proteins, and bacteria in the high-temperature and high-humidity environment of feed pelleting, reducing processing activity loss. It also prevents the aggregation of nano-sized hydrotalcite particles, ensuring uniform dispersion of functional components and facilitating nutrient absorption and utilization by pigs. Grafted 2-vinylpyridine is protonated under gastric pH conditions, adsorbing anti-nutritional factors and harmful substances, reducing damage to intestinal epithelial cells and excessive activation of the immune system. The extended polymer brush segments isolate gastric acid and pepsin, preventing premature inactivation of the complex enzyme preparation and probiotics. As the pH of the digesta increases, the polymer brush conformation changes, precisely releasing the complex enzyme preparation to the anterior end of the small intestine, improving enzymatic hydrolysis efficiency and restoring the anion exchange capacity of the hydrotalcite layer to continue adsorbing residual anti-nutritional factors. The copolymer layer on the modified hydrotalcite surface forms a hydrogen bond network with the intestinal mucus layer, prolonging the retention time of enzyme preparations and probiotics in the intestinal wall, creating a favorable microenvironment for competitive colonization of probiotics, extending the enzyme's action window, and improving the efficiency of nutrient digestion and absorption.

[0062] As shown in Table 2, the diarrhea rate in groups 1-6 of Examples 1-6 was significantly lower than that in the comparative and control groups. This indicates that the feed formulation using modified hydrotalcite, compound enzyme preparations, and probiotic preparations can effectively reduce the incidence of diarrhea in fattening pigs.

[0063] Comparison between the comparative and control groups: The diarrhea rate in the comparative group was lower than that in the control group, but higher than that in the example group. This indicates that modified hydrotalcite, compound enzyme preparations, and probiotic preparations all have a certain effect on reducing the diarrhea rate, but the combined use of the three has a more significant effect.

[0064] Modified hydrotalcite adsorbs negatively charged anti-nutritional factors and harmful substances such as mycotoxins, phytic acid, and bacterial endotoxins in gastric juice, reducing damage to intestinal epithelial cells and overactivation of the immune system, thereby reducing the risk of diarrhea; probiotic preparations regulate the balance of intestinal flora, inhibit the growth of harmful bacteria, and enhance intestinal barrier function, which also helps to reduce the diarrhea rate.

[0065] As shown in Table 3, the dry matter digestibility, crude protein digestibility, and crude fat digestibility of groups 1-6 were significantly higher than those of the comparative and control groups. This indicates that the feed formulation can improve the digestibility and absorption of nutrients in fattening pigs.

[0066] The nutrient digestibility of the comparative group was higher than that of the control group, but lower than that of the example group. This indicates that modified hydrotalcite, compound enzyme preparation, and probiotic preparation all contribute to improving nutrient digestibility, and the synergistic effect of the three is better.

[0067] Modified hydrotalcite precisely releases the complex enzyme preparation into the proximal small intestine, maximizing enzymatic hydrolysis efficiency and helping to improve the digestion of nutrients. The copolymer layer on the surface of the modified hydrotalcite prolongs the hydrolysis reaction window of the enzyme preparation in the action area, further promoting the digestion of nutrients. The probiotic preparation improves the intestinal microecological environment, enhances intestinal digestive function, and is also conducive to the absorption and utilization of nutrients.

[0068] Table 4 shows that the serum total protein (TP) and albumin (ALB) levels were higher in groups 1-6, while the blood urea nitrogen (BUN) level was lower, the glucose (GLU) level was stable, and the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were lower. This indicates that the fattening pigs using this feed formula have strong protein synthesis capabilities, good metabolic status, and normal liver function.

[0069] The serum biochemical indicators in the comparative group were better than those in the control group, but worse than those in the example group. This indicates that modified hydrotalcite, compound enzyme preparations, and probiotic preparations all have a certain effect on improving the serum biochemical indicators of fattening pigs, and the combined use of the three has a more prominent effect.

[0070] The synergistic effect of modified hydrotalcite, compound enzyme preparations, and probiotic preparations improves the efficiency of nutrient digestion and absorption, provides sufficient raw materials for protein synthesis, thereby increasing the content of serum total protein and albumin; reduces the damage of anti-nutritional factors and harmful substances to the body, reduces the metabolic burden on the liver, maintains normal liver function, and keeps the activities of alanine aminotransferase and aspartate aminotransferase at a low level; stable energy supply and good metabolic status keep glucose content stable and reduce urea nitrogen content.

[0071] In summary, this invention, through the synergistic use of modified hydrotalcite, compound enzyme preparations, and probiotic preparations, can significantly improve the growth performance of fattening pigs, reduce diarrhea rate, increase nutrient digestibility, and improve serum metabolic indicators.

[0072] In the description of this specification, the terms "preparation example," "example," "various examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that example or preparation example, which are included in at least one example or preparation example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same example or preparation example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more examples or preparation examples.

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A growth-promoting feed for fattening pigs, characterized in that, By weight, it includes the following raw materials: 600-650 parts corn, 40-60 parts wheat bran, 200-240 parts soybean meal, 20-40 parts rapeseed meal, 10-20 parts fish meal, 0.5-2.0 parts modified hydrotalcite, 0.05-0.2 parts compound enzyme preparation, 0.05-0.2 parts probiotic preparation, 10-15 parts dicalcium phosphate, 5-10 parts limestone powder, 3-4 parts salt, 0.1-0.2 parts zinc oxide, 0.01-0.03 parts copper sulfate pentahydrate, 15-25 parts soybean oil, 0.5-1.5 parts choline chloride, 0.2-0.8 parts antifungal agent, and 0.01-0.05 parts antioxidant. Among them, the modified hydrotalcite is a functionalized hydrotalcite obtained by modifying magnesium aluminum hydrotalcite with a silane coupling agent and then grafting it with methacrylamide and 2-vinylpyridine.

2. The growth-promoting feed for fattening pigs according to claim 1, characterized in that, Modified hydrotalcite is prepared by the following steps: S1. After drying the magnesium aluminum hydrotalcite, disperse it in N,N-dimethylformamide, add vinyltriethoxysilane and reflux to obtain vinyl-functionalized magnesium aluminum hydrotalcite; S2. The vinyl-functionalized magnesium aluminum hydrotalcite obtained in step S2 is dispersed in N,N-dimethylformamide, methacrylamide, 2-vinylpyridine and an initiator are added, and a graft copolymerization reaction is carried out under a protective gas atmosphere to obtain modified hydrotalcite.

3. The growth-promoting feed for fattening pigs according to claim 1, characterized in that, The compound enzyme preparation is selected from one or more of xylanase, β-glucanase, cellulase, and phytase; the probiotic preparation is selected from one or more of lactic acid bacteria, Bacillus subtilis, and yeast.

4. The growth-promoting feed for fattening pigs according to claim 1, characterized in that, The antifungal agent is selected from one or more of calcium propionate, sodium diacetate, and potassium sorbate; the antioxidant is selected from one or more of ethoxyquinoline, butylated hydroxyanisole, and butylated hydroxytoluene.

5. The growth-promoting feed for fattening pigs according to claim 2, characterized in that, In step S1, the mass-to-volume ratio of magnesium aluminum hydrotalcite to vinyltriethoxysilane is 1 g: (0.5-0.8) mL.

6. The growth-promoting feed for fattening pigs according to claim 2, characterized in that, In step S1, the reflux reaction temperature is 100-120℃ and the time is 20-28h.

7. The growth-promoting feed for fattening pigs according to claim 2, characterized in that, In step S2, the mass ratio of vinyl-functionalized magnesium aluminum hydrotalcite, methacrylamide, and 2-vinylpyridine is 1:(1.5-2.5):(2.5-3.5); the initiator is azobisisobutyronitrile, and its amount is 0.5-1.5% of the total mass of methacrylamide and 2-vinylpyridine.

8. The growth-promoting feed for fattening pigs according to claim 2, characterized in that, The graft copolymerization reaction in step S2 is carried out at a temperature of 65-80℃ for 10-15 hours.

9. A method for preparing a growth-promoting feed for fattening pigs as described in any one of claims 1-8, characterized in that, It is prepared by the following steps: Weigh each ingredient according to the specified weight proportions, mix them evenly, crush them, pass them through a 2.0-3.0mm sieve, and granulate them to a diameter of 3.0-5.0mm and a length of 6-15mm, thus obtaining the growth-promoting feed for fattening pigs.

Images