Intestine-protecting and digestible pig feed and preparation method thereof

Abstract

The present application relates to the technical field of feed, in particular to a kind of intestine-protecting easily-digestible pig feed and preparation method, comprising basic feed component and composite additive;Basic feed component is composed of the following raw materials: corn, puffed rice, puffed soybean, fermented soybean meal, fish meal, sugar beet meal, soybean oil, stone powder, calcium hydrogen phosphate, salt, lysine sulfate, methionine, and vitamin and trace element premix;Composite additive includes the complex of zinc element formed by the extract of Sargassum siliquastrum, laminaria polysaccharide extract;The complex exists in the form of solid powder, it is convenient to realize uniform mixing with corn, soybean meal and other basic feed raw materials, it is helpful to improve the problems such as feed caking, uneven mixing and poor flow caused by the possible addition of oily extract, avoid the risk of affecting palatability by local concentration being too high or being ineffective by concentration being too low.

Description

Technical Field

[0001] This invention relates to the field of feed technology, and in particular to a gut-protecting and easily digestible pig feed and its preparation method. Background Technology

[0002] As the material basis for pig growth, the nutritional composition of feed directly affects intestinal health and digestive function. For a long time, traditional pig feed formulation has focused on high protein and energy inputs to achieve rapid weight gain, often using large amounts of plant-based protein ingredients such as soybean meal. However, naturally occurring antigenic proteins (such as glycinin and β-conglycinin) and anti-nutritional factors like non-starch polysaccharides in these ingredients can easily induce intestinal allergic reactions during critical physiological stages such as weaning, leading to atrophy of intestinal villi and deepening of crypts, thereby damaging the intestinal mechanical barrier and absorption function. Simultaneously, undigested nutrients entering the hindgut provide a substrate for the proliferation of potential pathogens such as E. coli, disrupting the intestinal microecological balance and ultimately causing a series of problems such as diarrhea, growth retardation, and even increased mortality. Therefore, the development of gut-protecting, easily digestible pig feed is based on a deep understanding of pig digestive physiology and intestinal health, emphasizing the maintenance of the integrity of intestinal structure and function through nutritional regulation.

[0003] For example, patent publication number CN105831449A discloses a concentrated feed for weaned piglets containing chitosan oligosaccharides and its preparation method, comprising the following components: dicalcium phosphate, limestone powder, salt, lysine, choline chloride, organic iron, organic selenium, biogenic chromium, organic manganese, organic zinc, trace elements, vitamins, chitosan oligosaccharide powder, rice bran meal, and bentonite, etc. This invention, by adding chitosan oligosaccharides to the feed, can scavenge oxygen free radicals in the body, reduce cell damage caused by oxidation, protect the animal's intestines, and reduce the occurrence of diseases such as diarrhea.

[0004] However, while intestinal mucosal repair agents, such as zinc oxide, are significantly effective in treating diarrhea in weaned piglets, long-term use of high doses of zinc oxide can lead to the accumulation and pollution of heavy metal zinc in soil and water environments, and may induce co-drug resistance in bacteria. Plant extracts and antimicrobial peptides, as antibiotic alternatives, suffer from low extraction rates and poor stability, are easily inactivated during the high-temperature process of feed pelleting, and exhibit significant differences in active ingredients among plant materials from different origins and harvesting periods. Furthermore, probiotic preparations have low survival rates during storage and in acidic gastric environments, limited colonization capacity, and significantly different effects on pigs with different health conditions and feeding environments. While prebiotics can selectively promote the proliferation of beneficial bacteria, excessive addition may induce osmotic diarrhea and disrupt normal intestinal digestive rhythms. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides an intestinal-protecting and easily digestible pig feed and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A gut-protecting and easily digestible pig feed, comprising basic feed components and compound additives; The basic feed components consist of the following raw materials: corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, beet meal, soybean oil, limestone powder, dicalcium phosphate, salt, lysine sulfate, methionine, and vitamin and trace element premix. The compound additive contains extracts of *Euphorbia milii*, polysaccharide extracts of *Euphorbia milii*, and complexes formed by zinc.

[0007] Further, by weight, it comprises the following raw materials: 40-60 parts corn, 10-20 parts puffed rice, 5-10 parts puffed soybeans, 8-15 parts fermented soybean meal, 2-5 parts fish meal, 2-4 parts beet meal, 1-2 parts soybean oil, 1.2-2.5 parts limestone powder, 0.8-1.2 parts dicalcium phosphate, 0.3-0.5 parts salt, 0.1-0.4 parts lysine sulfate, 0.01-0.1 parts methionine, 0.01-0.2 parts vitamin and trace element premix, and 1-3 parts of the compound additive as described in claim 1.

[0008] Furthermore, the preparation method of the composite additive includes the following steps: S1. Take dried whole plant of *Gnaphalium affine* and pulverize it. Add ethanol solution for ultrasonic-assisted extraction. After filtration, concentration and drying, obtain *Gnaphalium affine* extract. The moisture content of dried whole plant of *Gnaphalium affine* is ≤8%. The particle size after pulverization is 40-60 mesh. The ratio of ethanol solution to whole plant of *Gnaphalium affine* is (10-20):1 (mL / g). Filtration is carried out using a 0.22-0.45μm filter membrane. The concentration temperature is 50-60℃ and the vacuum degree is 0.06-0.08MPa. The drying temperature is 60-70℃ and the drying time is 12-24h. S2. Take dried Euphorbia milii, crush it, add water for hot extraction, centrifuge the extract, take the supernatant, add ethanol for precipitation, collect the precipitate and dry it to obtain Euphorbia milii polysaccharide extract. The moisture content of dried Euphorbia milii is ≤10%, the particle size after crushing is 40-60 mesh, the ratio of water to Euphorbia milii is (15-25):1 (mL / g), the centrifugation speed is 3000-5000 rpm, the centrifugation time is 15-25 min, the precipitation standing time is 12-24 h, the drying temperature is 60-70℃, and the drying time is 8-12 h. S3. Dissolve the extracts of *Euphorbia milii* and *Euphorbia milii* polysaccharide extract in water, adjust the pH to acidic, add a solution containing zinc ions to react, separate, wash and dry the reaction product after the reaction is complete to obtain a composite additive. The total concentration of the extracts of *Euphorbia milii* and *Euphorbia milii* polysaccharide extract is 5-10 g / L. The pH is adjusted using a 0.1-0.5 mol / L hydrochloric acid solution, and the concentration of the zinc ion solution is 0.5-1.0 mol / L. During the reaction, the mixture is continuously stirred at a speed of 100-200 rpm. Separation is performed by centrifugation at a speed of 4000-6000 rpm. Washing is performed 3-5 times with deionized water. The mass ratio of washing solution to reaction product is (5-10):1 (mL / g) each time.

[0009] Furthermore, the vitamin and trace element premix contains one or more of the following: vitamin A, vitamin D3, vitamin E, vitamin K3, vitamin B1, vitamin B2, vitamin B6, vitamin B12, niacin, calcium pantothenate, folic acid, biotin, choline chloride, copper sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, calcium iodate, and sodium selenite. By weight, the content range of each component in the vitamin and trace element premix is ​​as follows: vitamin A 5000-10000 IU, vitamin D3 1000-2000 IU, vitamin E 20-50 IU, vitamin K3 1-3 mg, vitamin B1 1-2 mg, vitamin B2 2-4 mg, vitamin B6 1-3 mg, and vitamin B12... 0.01-0.02mg, niacin 10-20mg, calcium pantothenate 5-10mg, folic acid 0.5-1mg, biotin 0.05-0.1mg, choline chloride 500-1000mg, copper sulfate 50-100mg, ferrous sulfate 100-200mg, manganese sulfate 50-100mg, zinc sulfate 100-200mg, calcium iodate 1-2mg, sodium selenite 0.1-0.3mg.

[0010] Furthermore, in step S1, the volume concentration of the ethanol solution is 50-70%; the power of the ultrasonic-assisted extraction is 300-500W, the temperature is 40-50℃, and the time is 60-120min.

[0011] Furthermore, in step S2, the temperature of hot extraction is 85-95℃ and the time is 3-5h; the volume ratio of ethanol used for precipitation to supernatant is (2-4):1.

[0012] Further, in step S3, the mass ratio of *Euphorbia milii* extract to *Euphorbia milii* polysaccharide is 1:(2-5); the pH is adjusted to 4.5-5.5; the zinc-containing solution is an aqueous solution of zinc sulfate, zinc chloride, or zinc acetate; the reaction temperature is 40-50℃, and the reaction time is 4-6 h; when the zinc-containing solution is an aqueous solution of zinc sulfate, its concentration is 0.6-0.8 mol / L; when it is an aqueous solution of zinc chloride, its concentration is 0.5-0.7 mol / L; when it is an aqueous solution of zinc acetate, its concentration is 0.7-0.9 mol / L.

[0013] Furthermore, in step S3, the mass ratio of zinc ions to the total mass of *Gynostemma pentaphyllum* extract and *Euphorbia milii* polysaccharide extract is (8.2-21.8):1.

[0014] According to another aspect of the present invention, a method for preparing the above-mentioned intestinal-protecting and easily digestible pig feed is provided, comprising the following steps: Weigh out the raw materials according to the formula, and separately grind the corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, and beet meal. Then mix them with soybean oil, limestone powder, dicalcium phosphate, salt, lysine sulfate, methionine, vitamin and trace element premix, and compound additives to obtain a mixture. Granulate the mixture to obtain an intestinal-protecting and easily digestible pig feed. The particle size of the ground raw materials is 60-80 mesh. Mixing is done using a twin-shaft mixer at a speed of 200-300 rpm for 15-25 minutes. Granulation is done using a ring die pellet mill at a temperature of 80-90℃ and a die diameter of 2-4 mm. After granulation, cool to room temperature (20-25℃) for 30-60 minutes.

[0015] The beneficial effects of this invention are: 1. In the technical solution of this invention, the extract of *Euphorbia tirucalli* is rich in polyphenols with ortho- and olfactory hydroxyl groups and carboxyl groups, while the extract of *Euphorbia tirucalli* polysaccharide contains a large number of linear macromolecules with sulfate and hydroxyl groups. Zinc ions, acting as coordination centers, simultaneously form coordination bonds with the oxygen atoms of *Euphorbia tirucalli* polyphenols and the oxygen or sulfate groups on the polysaccharide chains, anchoring the small-molecule polyphenols onto the polysaccharide backbone and constructing an organic-inorganic hybrid three-dimensional network structure. The formation of coordination bonds and the steric hindrance effect of the three-dimensional network in this structure enable the active ingredients to remain relatively stable during the high-temperature process of feed pelleting and in the acidic environment of the stomach, providing better protection than physical adsorption methods. This allows more active ingredients to reach the intestines, where the complexes gradually dissociate in the intestinal environment, realizing the release of *Euphorbia tirucalli* polyphenols, *Euphorbia tirucalli* polysaccharides, and zinc ions into the intestinal region.

[0016] 2. In terms of antioxidant effects, the intramolecular electron cloud distribution of *Euphorbia tirucalli* polyphenols changes after coordination with zinc ions, correspondingly increasing the reactivity of the phenolic hydroxyl groups and enhancing their ability to scavenge free radicals, thus helping to alleviate oxidative stress damage that intestinal epithelial cells may face. In terms of antibacterial effects, the formed complexes carry a positively charged surface, easily adsorbing negatively charged pathogens and influencing bacterial cell membrane structure. Simultaneously, the released polyphenols and zinc ions can act on bacterial metabolic processes and enzyme systems, respectively, thereby inhibiting pathogens. In terms of intestinal barrier maintenance, the zinc ions released after the complexes dissociate participate in the synthesis of tight junction proteins and cell proliferation. *Euphorbia tirucalli* polyphenols have a certain regulatory effect on local inflammatory responses, while *Euphorbia tirucalli* polysaccharides can affect the expression of intestinal immune-related factors, contributing to the maintenance of intestinal health.

[0017] 3. This invention integrates zinc ions into a three-dimensional network structure, achieving the slow release of zinc. This avoids the resource waste and environmental emissions that may result from the rapid dissociation of high doses of zinc ions in the stomach. Even with relatively low addition amounts, it still achieves a sustained intestinal mucosal repair effect, which is significant for reducing the accumulation of heavy metal zinc in the environment. Simultaneously, the complex exists in solid powder form, facilitating uniform mixing with basic feed ingredients such as corn and soybean meal. This helps improve problems such as feed clumping, uneven mixing, and poor flowability that may occur with the direct addition of oil extracts, resulting in a more uniform distribution of active ingredients in the feed and avoiding the risks of excessively high local concentrations affecting palatability or excessively low concentrations causing ineffectiveness. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the preparation process of the present invention. 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] In the following preparation examples and embodiments, the whole herb of *Melastoma dodecandrum* Lour. was pulverized before use, and the moisture content was controlled between 7-8%. *Eucheuma* spp. was pulverized before use, and the moisture content was controlled between 9-10%. Zinc sulfate (ZnSO4·7H2O, analytical grade) with zinc ion content conforming to GB / T 666-2011 was used. The feed ingredients, including corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, beet meal, soybean oil, limestone powder, dicalcium phosphate, salt, lysine sulfate, methionine, vitamins, and trace elements premix, were all provided by Jiangxi Zhengbang Technology Co., Ltd. The vitamins and trace elements premix met the NRC (2012) standards for swine nutritional requirements.

[0021] Preparation Example 1 The compound additive includes the following steps: S1. Take 1g of dried whole herb of *Gnaphalium affine* with a moisture content of 7%, pulverize it to 40 mesh, add 10mL of 50% ethanol solution, and extract with ultrasonic assistance at 300W and 40℃ for 60min. Filter the extract through a 0.22μm filter membrane, concentrate it at 50℃ and 0.06MPa, and dry it for 12h to obtain *Gnaphalium affine* extract. S2. Take 1g of dried Euphorbia milii with a moisture content of 9%, grind it to 40 mesh, add 15mL of water, and hot extract at 85℃ for 3h, stirring for 5min every 30min during the process. Centrifuge the extract at 3000rpm for 15min, take the supernatant, add 24mL of 95% ethanol, let it stand at 4℃ for 12h to precipitate, collect the precipitate, and dry it at 60℃ for 8h to obtain Euphorbia milii polysaccharide extract. S3. Take 0.1g of *Euphorbia hirta* extract and 0.2g of *Euphorbia hirta* polysaccharide extract, dissolve them in 60mL of water, adjust the pH to 4.5 with 0.1mol / L hydrochloric acid solution, add 0.5mol / L zinc sulfate aqueous solution containing 0.82g of zinc ions, stir continuously at 40℃ and 100r / min for 4h. After the reaction is completed, centrifuge at 4000rpm, wash three times with deionized water, and dry to obtain the composite additive.

[0022] Preparation Example 2 The compound additive includes the following steps: S1. Take 1g of dried whole herb of *Gnaphalium affine* with a moisture content of 8%, pulverize it to 50 mesh, add 15mL of 60% ethanol solution, and extract with ultrasonic assistance at 400W and 45℃ for 90min. Filter the extract through a 0.3μm filter membrane, concentrate it at 55℃ and 0.07MPa, and dry it for 18h to obtain *Gnaphalium affine* extract. S2. Take 1g of dried Euphorbia milii with a moisture content of 10%, grind it to 50 mesh, add 20mL of water, and hot extract at 90℃ for 4h, stirring for 5min every 30min during the process. Centrifuge the extract at 4000rpm for 20min, take the supernatant, add 48mL of 96% ethanol, let it stand at 6℃ for 18h to precipitate, collect the precipitate, and dry it at 65℃ for 10h to obtain Euphorbia milii polysaccharide extract. S3. Take 0.1g of *Euphorbia hirta* extract and 0.35g of *Euphorbia hirta* polysaccharide extract, dissolve them in 90mL of water, adjust the pH to 5.0 with 0.3mol / L hydrochloric acid solution, add 0.7mol / L zinc chloride aqueous solution containing 6.75g of zinc ions at a rate of 0.75mL / min, stir continuously at 45℃ and 150r / min for 5h, centrifuge at 5000rpm after the reaction is completed, wash 4 times with deionized water, and dry to obtain the composite additive.

[0023] Preparation Example 3 The compound additive includes the following steps: S1. Take 1g of dried whole herb of *Gnaphalium affine* with a moisture content of 7.5%, pulverize it to 60 mesh, add 20mL of 70% ethanol solution, and extract with ultrasonic assistance at 500W and 50℃ for 120min. Filter the extract through a 0.45μm filter membrane, concentrate it at 60℃ and 0.08MPa, and dry it for 24h to obtain *Gnaphalium affine* extract. S2. Take 1g of dried Euphorbia lactea with a moisture content of 9.5%, grind it to 60 mesh, add 25mL of water, and hot extract at 95℃ for 5h, stirring for 5min every 30min during the process. Centrifuge the extract at 5000rpm for 25min, take the supernatant, add 80mL of 98% ethanol, let it stand at 8℃ for 24h to precipitate, collect the precipitate, and dry it at 70℃ for 12h to obtain Euphorbia lactea polysaccharide extract. S3. Take 0.1g of *Euphorbia hirta* extract and 0.5g of *Euphorbia hirta* polysaccharide extract, dissolve them in 120mL of water, adjust the pH to 5.5 with 0.5mol / L hydrochloric acid solution, add 0.9mol / L zinc acetate aqueous solution containing 13.08g of zinc ions, and stir continuously at 50℃ and 200r / min for 6h. After the reaction is completed, centrifuge at 6000rpm, wash 5 times with deionized water, and dry to obtain the composite additive.

[0024] Example 1

[0025] A gut-protecting and easily digestible pig feed is prepared by the following steps: Weigh the following ingredients by weight: 40 parts corn, 10 parts puffed rice, 5 parts puffed soybeans, 8 parts fermented soybean meal, 2 parts fish meal, 2 parts beet meal, 1 part soybean oil, 1.2 parts limestone powder, 0.8 parts dicalcium phosphate, 0.3 parts salt, 0.1 parts lysine sulfate, 0.01 parts methionine, and 0.01 parts vitamin and trace element premix (containing 5000 IU of vitamin A, 1000 IU of vitamin D3, and vitamin E). 20 IU, 50 mg copper sulfate, 100 mg ferrous sulfate, 100 mg zinc sulfate), and one part of the compound additive prepared in Example 1 were used. Corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, and beet meal were weighed according to the weight proportions and crushed to 60 mesh. They were then added together with the remaining raw materials to a twin-shaft mixer and mixed at 200 rpm for 15 min to obtain a mixture. The mixture was then fed into a ring die pellet mill and pelleted at 80°C with a ring die aperture of 2 mm. After pelleting, the mixture was cooled to 20°C to obtain an intestinal-protecting and easily digestible pig feed.

[0026] Example 2

[0027] A gut-protecting and easily digestible pig feed is prepared by the following steps: Weigh the following ingredients by weight: 50 parts corn, 15 parts puffed rice, 7.5 parts puffed soybeans, 11.5 parts fermented soybean meal, 3.5 parts fish meal, 3 parts beet meal, 1.5 parts soybean oil, 1.85 parts limestone powder, 1.0 part dicalcium phosphate, 0.4 parts salt, 0.25 parts lysine sulfate, 0.055 parts methionine, and 0.105 parts vitamin and trace element premix (containing 7500 IU vitamin A, 1500 IU vitamin D3, 35 IU vitamin E, 2 mg vitamin K3, and vitamin B1). 1.5 mg of copper sulfate, 75 mg of copper sulfate, 150 mg of ferrous sulfate, 150 mg of zinc sulfate, 75 mg of manganese sulfate, and 1.5 mg of calcium iodate were added to two portions of the compound additive prepared in Example 2. The corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, and beet meal were weighed according to the weight proportions and pulverized to 70 mesh. They were then added together with the remaining raw materials to a twin-shaft mixer and mixed at 250 rpm for 20 minutes to obtain a mixture. The mixture was then fed into a ring die pellet mill and pelleted at 85°C with a ring die aperture of 3 mm. After pelleting, the mixture was cooled to 22.5°C to obtain an intestinal-protecting and easily digestible pig feed.

[0028] Example 3

[0029] A gut-protecting and easily digestible pig feed is prepared by the following steps: Weigh the following ingredients by weight: 60 parts corn, 20 parts puffed rice, 10 parts puffed soybeans, 15 parts fermented soybean meal, 5 parts fish meal, 4 parts beet meal, 2 parts soybean oil, 2.5 parts limestone powder, 1.2 parts dicalcium phosphate, 0.5 parts salt, 0.4 parts lysine sulfate, 0.1 parts methionine, and 0.2 parts vitamin and trace element premix (containing 10000 IU vitamin A, 2000 IU vitamin D3, 50 IU vitamin E, 3 mg vitamin B2, 2 mg vitamin B6, and 2 mg vitamin B12). Three portions of the compound additive prepared in Example 3 (0.015 mg, copper sulfate 100 mg, ferrous sulfate 200 mg, zinc sulfate 200 mg, manganese sulfate 100 mg, sodium selenite 0.2 mg) were prepared. Corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, and beet meal were weighed according to the weight proportions and pulverized to 80 mesh. They were then added together with the remaining raw materials into a twin-shaft mixer and mixed at 300 rpm for 25 min to obtain a mixture. The mixture was then fed into a ring die pellet mill and pelleted at 90°C with a ring die aperture of 4 mm. After pelleting, the mixture was cooled to 25°C to obtain an intestinal-protecting and easily digestible pig feed.

[0030] Example 4

[0031] A gut-protecting and easily digestible pig feed is prepared by the following steps: Weigh the following ingredients by weight: 45 parts corn, 12 parts puffed rice, 6 parts puffed soybeans, 10 parts fermented soybean meal, 3 parts fish meal, 2.5 parts beet meal, 1.2 parts soybean oil, 1.5 parts limestone powder, 0.9 parts dicalcium phosphate, 0.35 parts salt, 0.15 parts lysine sulfate, 0.03 parts methionine, and 0.05 parts vitamin and trace element premix (containing 6000 IU of vitamin A, 1200 IU of vitamin D3, and vitamin E). 25 IU, nicotinic acid 12 mg, calcium pantothenate 6 mg, copper sulfate 60 mg, ferrous sulfate 120 mg, zinc sulfate 120 mg, manganese sulfate 60 mg, calcium iodate 1.2 mg), and 1.5 parts of the compound additive prepared in Example 1 were used. Corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, and beet meal were weighed according to the weight proportions and crushed to 65 mesh. They were then added together with the remaining raw materials into a twin-shaft mixer and mixed at 220 rpm for 18 min to obtain a mixture. The mixture was then fed into a ring die pellet mill and pelleted at 82°C with a ring die aperture of 2.5 mm. After pelleting, the pellets were cooled to 21°C to obtain an intestinal-protecting and easily digestible pig feed.

[0032] Example 5

[0033] A gut-protecting and easily digestible pig feed is prepared by the following steps: Weigh the following ingredients by weight: 55 parts corn, 18 parts puffed rice, 8 parts puffed soybeans, 13 parts fermented soybean meal, 4 parts fish meal, 3.5 parts beet meal, 1.8 parts soybean oil, 2.2 parts limestone powder, 1.1 parts dicalcium phosphate, 0.45 parts salt, 0.3 parts lysine sulfate, 0.07 parts methionine, and 0.15 parts vitamin and trace element premix (containing 8500 IU of vitamin A, 1800 IU of vitamin D3, and vitamin E). 40 IU, folic acid 0.7 mg, biotin 0.07 mg, choline chloride 700 mg, copper sulfate 85 mg, ferrous sulfate 180 mg, zinc sulfate 180 mg, manganese sulfate 85 mg, sodium selenite 0.25 mg), and 2.5 parts of the compound additive prepared in Example 2 were mixed together with corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, and beet meal weighed according to the weight proportions and pulverized to 75 mesh. The mixture was then added to a twin-shaft mixer and mixed at 280 rpm for 22 min to obtain a mixture. The mixture was then fed into a ring die pellet mill and pelleted at 88°C with a ring die aperture of 3.5 mm. After pelleting, the pellets were cooled to 24°C to obtain an intestinal-protecting and easily digestible pig feed.

[0034] Example 6

[0035] A gut-protecting and easily digestible pig feed is prepared by the following steps: Weigh the following ingredients by weight: 48 parts corn, 16 parts puffed rice, 7 parts puffed soybeans, 12 parts fermented soybean meal, 3.8 parts fish meal, 3.2 parts beet meal, 1.6 parts soybean oil, 2.0 parts limestone powder, 1.05 parts dicalcium phosphate, 0.42 parts salt, 0.28 parts lysine sulfate, 0.06 parts methionine, and 0.12 parts vitamin and trace element premix (containing 7000 IU vitamin A, 1600 IU vitamin D3, 32 IU vitamin E, 1.8 mg vitamin B6, and 1.8 mg vitamin B12). 0.012 mg of nicotinic acid, 16 mg of copper sulfate, 70 mg of ferrous sulfate, 160 mg of zinc sulfate, 160 mg of manganese sulfate, 70 mg of calcium iodate, and 1.6 mg of calcium iodate were added to a 2.2-part compound additive prepared in Example 3. Corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, and beet meal, weighed according to their weight proportions, were pulverized to 72 mesh and added together with the remaining raw materials to a twin-shaft mixer. The mixture was mixed at 260 rpm for 21 minutes to obtain a mixture. This mixture was then fed into a ring die pellet mill and pelleted at 86°C with a ring die aperture of 3.2 mm. After pelleting, the pellets were cooled to 23°C to obtain an intestinal-protecting and easily digestible pig feed.

[0036] Comparative Example 1 The difference between this comparative example and Preparation Example 1 is that step S1 is omitted, that is, the extract of *Gynostemma pentaphyllum* is not added in step S3, while the remaining steps are the same as those in Preparation Example 1.

[0037] Comparative Example 2 The difference between this comparative example and preparation example 2 is that step S2 is not performed, that is, the extract of Euphorbia lactea polysaccharide is not added in step S3, and the remaining steps are the same as those in preparation example 2.

[0038] Comparative Example 3 The difference between this comparative example and preparation example 3 is that steps S1 and S2 are omitted, that is, the extracts of *Euphorbia milii* and *Euphorbia milii* polysaccharide extract are not added in step S3. The remaining steps are the same as those in preparation example 3.

[0039] Comparative Example 4 The difference between this comparative example and Preparation Example 1 is that zinc sulfate aqueous solution is not added in step S3, while the remaining steps are the same as in Preparation Example 1.

[0040] Comparative Example 5 The difference between this comparative example and Example 1 is that the additive obtained in Comparative Example 1 is used, while the remaining steps are the same as in Example 1.

[0041] Comparative Example 6 The difference between this comparative example and Example 2 is that the additive obtained in Comparative Example 2 is used, while the remaining steps are the same as in Example 2.

[0042] Comparative Example 7 The difference between this comparative example and Example 3 is that the additive obtained in Comparative Example 3 is used, while the remaining steps are the same as in Example 3.

[0043] Comparative Example 8 The difference between this comparative example and Example 4 is that the additive obtained in Comparative Example 4 is used, while the remaining steps are the same as in Example 4.

[0044] Comparative Example 9 The difference between this comparative example and Example 5 is that no additives are added, while the remaining steps are the same as in Example 5.

[0045] Comparative Example 10 The difference between this comparative example and Example 6 is that puffed rice is not added; the remaining steps are the same as in Example 6.

[0046] Comparative Example 11 The difference between this comparative example and Example 1 is that puffed soybeans are not added; the remaining steps are the same as in Example 1.

[0047] Comparative Example 12 The difference between this comparative example and Example 2 is that fermented soybean meal is not added; the remaining steps are the same as in Example 2.

[0048] Healthy weaned piglets of similar weight (9.5-10.5 kg) were placed in the nursery for a 7-day pre-feeding period. During this period, all piglets were fed a uniform basal diet without experimental additives. Their health was observed daily, and unhealthy individuals were removed. After the pre-feeding period, all piglets were weighed on an empty stomach and randomly divided into 14 treatment groups (fed the experimental diets corresponding to Examples 1-6 and Comparative Examples 5-12, respectively), and housed in individual pens. Feed intake in each pen was measured and recorded at a fixed time each morning, and uneaten feed was measured and recorded at the same time the following morning to calculate the precise feed intake for that pen the previous day. Fresh feed and clean, sufficient drinking water were ensured.

[0049] On the first day (initial weight) and the morning of the 35th day (final weight), all experimental pigs were weighed on an empty stomach. The average daily feed intake (ADFI) was calculated based on the total feed intake records for each pen over 35 days. The average daily gain (ADG) was calculated based on the initial and final weights of each pig. The feed conversion ratio (F / G) was calculated based on the pen's ADFI and the pen's average ADG. The formula is as follows:

[0050]

[0051]

[0052] The results are shown in Table 1: Table 1. Effects of different feeds on the growth performance of weaned piglets

[0053]

[0054] Digestion tests were conducted from day 28 to day 32 of the experiment. Each morning, 0.3% chromium trioxide indicator (by weight of feed) was premixed with a small amount of feed, then gradually added to all feed in each pen that day. During the collection period, fresh feces from each pen were collected at 8:00 AM and 4:00 PM daily, after removing feathers, dander, and other foreign matter, and immediately mixed. Approximately 200 grams of the mixed feces from each pen each day was taken as a representative sample and placed in a labeled sample tray. Representative feces samples collected from the same pen over five consecutive days were mixed thoroughly and dried in a 65°C forced-air drying oven to constant weight. The dried feces samples were then pulverized, passed through a 40-mesh sieve, and placed in sealed bags for analysis. Feed samples for each treatment group were also prepared (similarly pulverized and passed through a 40-mesh sieve). The dry matter (DM) and crude protein (CP) content in the feed and corresponding feces samples were determined using chemical analysis. The chromium (Cr) content was determined using atomic absorption spectrometry or spectrophotometry. Calculate the apparent digestibility of dry matter and crude protein. The formula is as follows:

[0055] The nutrient content in feed and feces refers to the dry matter (DM) or crude protein (CP) content (%). When calculating dry matter digestibility, the nutrient content is simply the dry matter itself; therefore, the dry matter content in feed is 100%, and the dry matter content in feces is the measured value (%). When calculating crude protein digestibility, the nutrient content is the crude protein content (%). The results are shown in Table 2. Table 2. Effects of different feeds on apparent nutrient digestibility in weaned piglets

[0056]

[0057] On the morning of day 35 of the experiment, after weighing, three healthy piglets whose weight was closest to the average weight of each group were selected as sampling pigs. Blood was collected from each selected pig via anterior vena cava puncture, approximately 10 mL per pig. The blood was injected into sterile coagulation tubes and incubated at room temperature at an angle for 30-60 minutes until coagulation. The blood was then centrifuged at 3000 rpm for 15 minutes. The supernatant serum was carefully aspirated using a pipette and aliquoted into 2 mL centrifuge tubes. These tubes were immediately stored in a refrigerator for the determination of serum total antioxidant capacity (T-AOC) and diamine oxidase (DAO) activity. The results are shown in Table 3. Table 3. Effects of different diets on serum antioxidant and intestinal barrier parameters in weaned piglets

[0058]

[0059] Table 1 shows that the average daily feed intake of Examples 1-6 ranged from 882.4 to 918.6 g, the average daily weight gain ranged from 541.5 to 557.3 g, and the feed conversion ratio ranged from 1.630 to 1.650. This indicates that using feed containing compound additives resulted in better growth performance in weaned piglets, with relatively high feed intake and daily weight gain, and relatively low feed conversion ratios, suggesting high feed conversion efficiency. Comparative Examples 5-8 lacked certain components of the compound additives, while Comparative Example 9 did not add any compound additives. The average daily feed intake and average daily weight gain of these comparative examples were lower than those of the Example group, while their feed conversion ratios were higher. This indicates that the compound additives and their components have a significant impact on the growth performance of weaned piglets, and the lack of any component will lead to a decline in growth performance. Comparative Example 10 did not add extruded rice, Comparative Example 11 did not add extruded soybeans, and Comparative Example 12 did not add fermented soybean meal. Their average daily feed intake and average daily weight gain were also lower than those of the Example group, while their feed conversion ratios were higher. This indicates that raw materials such as puffed rice, puffed soybeans, and fermented soybean meal also have a positive effect on the growth performance of weaned piglets, possibly because these raw materials provide nutrients that are more easily digested and absorbed, thus promoting the growth of piglets.

[0060] Table 2 shows that the apparent digestibility of dry matter in Examples 1-6 ranged from 84.26% to 85.34%, and the apparent digestibility of crude protein ranged from 83.48% to 84.67%. This indicates that weaned piglets using feed containing compound additives have a stronger ability to digest dry matter and crude protein. The apparent digestibility of dry matter and crude protein in Comparative Examples 5-9 was lower than that in the Example groups. This indicates that the compound additives and their components help improve the digestibility of nutrients in weaned piglets, possibly because the components in the compound additives can regulate the intestinal environment of piglets, promote the secretion of digestive enzymes, and enhance the absorption of nutrients in the intestines. The apparent digestibility of dry matter and crude protein in Comparative Examples 10-12 was also lower than that in the Example groups. This indicates that raw materials such as extruded rice, extruded soybeans, and fermented soybean meal can improve the digestibility of feed, possibly because the extrusion or fermentation process destroys anti-nutritional factors in these raw materials, thereby improving the utilization rate of nutrients.

[0061] Table 3 shows that the serum total antioxidant capacity of Examples 1-6 ranged from 4.23 to 4.62 U / mL, and the serum diamine oxidase activity ranged from 7.93 to 8.67 U / L. The higher serum total antioxidant capacity indicates a stronger antioxidant system in piglets, enabling them to better scavenge free radicals and reduce oxidative stress damage to cells. The lower serum diamine oxidase activity indicates better intestinal barrier function and higher intestinal mucosal integrity, reducing the entry of intestinal endotoxins and other substances into the bloodstream. Comparative Examples 5-9 showed lower serum total antioxidant capacity and higher serum diamine oxidase activity than the Example groups. This indicates that the compound additive and its components can improve the antioxidant capacity and enhance the intestinal barrier function of weaned piglets. This is likely due to the combined effects of the components in the compound additive, the antioxidants in the *Euphorbia milii* extract, the protective effect of *Euphorbia milii* polysaccharide extract on the intestinal mucosa, and the regulatory effect of zinc ions on the immune system and intestinal function. Comparative Examples 10-12 also showed differences in serum total antioxidant capacity and serum diamine oxidase activity compared to the Example groups, but these differences were not as significant as those in the additive-related comparative examples. This indicates that raw materials such as puffed rice, puffed soybeans, and fermented soybean meal also have some impact on the antioxidant capacity and intestinal barrier function of piglets, but the role of compound additives is more critical.

[0062] In summary, the *Euphorbia hirta* extract in the compound additive may contain various bioactive components, such as flavonoids and polyphenols, which have antioxidant and anti-inflammatory effects, enhancing the antioxidant capacity of piglets and reducing oxidative stress damage to the intestines. *Euphorbia hirta* polysaccharide extract can regulate the balance of intestinal flora, promote the growth of beneficial bacteria, enhance the barrier function of the intestinal mucosa, and reduce the absorption of intestinal toxins. Zinc ions are cofactors for many enzymes, participating in immune regulation and intestinal development, and can enhance the immunity and intestinal function of piglets. Extruded rice, extruded soybeans, and fermented soybean meal, after special processing, improve the digestibility and utilization of nutrients, providing sufficient nutritional support for piglet growth. Therefore, feed containing compound additives and a reasonable ratio of raw materials can significantly improve the growth performance, nutrient digestibility, antioxidant capacity, and intestinal barrier function of weaned piglets.

[0063] In the description of this specification, the reference to terms such as "embodiment," "various embodiments," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or preparation example is included in at least one embodiment of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0064] 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 type of easily digestible, gut-protecting pig feed, characterized in that, It contains basic feed components and compound additives; The basic feed components consist of the following raw materials: corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, beet meal, soybean oil, limestone powder, dicalcium phosphate, salt, lysine sulfate, methionine, and vitamin and trace element premix. The compound additive contains extracts of *Euphorbia milii*, polysaccharide extracts of *Euphorbia milii*, and complexes formed by zinc.

2. The easily digestible, gut-protecting pig feed according to claim 1, characterized in that, By weight, it comprises the following raw materials: 40-60 parts corn, 10-20 parts puffed rice, 5-10 parts puffed soybeans, 8-15 parts fermented soybean meal, 2-5 parts fish meal, 2-4 parts beet meal, 1-2 parts soybean oil, 1.2-2.5 parts limestone powder, 0.8-1.2 parts dicalcium phosphate, 0.3-0.5 parts salt, 0.1-0.4 parts lysine sulfate, 0.01-0.1 parts methionine, 0.01-0.2 parts vitamin and trace element premix, and 1-3 parts of the compound additive as described in claim 1.

3. The easily digestible, gut-protecting pig feed according to claim 1 or 2, characterized in that, The preparation method of the composite additive includes the following steps: S1. Take dried whole plant of *Gnaphalium affine* and crush it. Add ethanol solution and perform ultrasonic-assisted extraction. After filtration, concentration and drying, obtain *Gnaphalium affine* extract. S2. Take dried Euphorbia milii, crush it, add water for hot extraction, centrifuge the extract, take the supernatant, add ethanol for precipitation, collect the precipitate and dry it to obtain Euphorbia milii polysaccharide extract. S3. Dissolve the extracts of *Euphorbia hirta* and *Euphorbia milii* polysaccharide extract in water, adjust the pH to acidic, add a solution containing zinc ions to react, and after the reaction is completed, separate, wash and dry the reaction product to obtain the composite additive.

4. The easily digestible, gut-protecting pig feed according to claim 2, characterized in that, The vitamin and trace element premix contains one or more of the following: vitamin A, vitamin D3, vitamin E, vitamin K3, vitamin B1, vitamin B2, vitamin B6, vitamin B12, niacin, calcium pantothenate, folic acid, biotin, choline chloride, copper sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, calcium iodate, and sodium selenite.

5. The easily digestible, gut-protecting pig feed according to claim 3, characterized in that, In step S1, the volume concentration of the ethanol solution is 50-70%; the power of the ultrasonic-assisted extraction is 300-500W, the temperature is 40-50℃, and the time is 60-120min.

6. The easily digestible, gut-protecting pig feed according to claim 3, characterized in that, In step S2, the temperature for hot extraction is 85-95℃ and the time is 3-5h; the volume ratio of ethanol used for precipitation to supernatant is (2-4):

1.

7. The easily digestible, gut-protecting pig feed according to claim 3, characterized in that, In step S3, the mass ratio of *Euphorbia milii* extract to *Euphorbia milii* polysaccharide is 1:(2-5); the pH is adjusted to 4.5-5.5; the zinc-containing solution is an aqueous solution of zinc sulfate, zinc chloride, or zinc acetate; the reaction temperature is 40-50℃, and the reaction time is 4-6 h.

8. The easily digestible, gut-protecting pig feed according to claim 3, characterized in that, In step S3, the mass ratio of zinc ions to the total mass of *Gynostemma pentaphyllum* extract and *Euphorbia milii* polysaccharide extract is (8.2-21.8):

1.

9. A method for preparing an intestinal-protecting and easily digestible pig feed as described in any one of claims 1-8, characterized in that, Includes the following steps: Weigh out each ingredient according to the formula, crush corn, puffed rice, puffed soybeans, fermented soybean meal, fish meal, and beet meal separately, and then mix them with soybean oil, limestone powder, dicalcium phosphate, salt, lysine sulfate, methionine, vitamin and trace element premix, and compound additives to obtain a mixture. Granulate the mixture to obtain an intestinal-protecting and easily digestible pig feed.

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