Rumen microbial preparation, preparation method and application thereof

Abstract

The application relates to a microbial preparation passing through the rumen, a preparation method and application thereof. The microbial preparation passing through the rumen comprises microbial powder and a coating material coated on the surface of the microbial powder. The coating material comprises protective fat. The total weight of fatty acids in the microbial preparation passing through the rumen is 100%, the fatty acids comprise 70wt%-80wt% of palmitic acid and stearic acid, <=9wt% of oleic acid, 5wt%-15wt% of polyunsaturated fatty acids and a residual amount of non-target fatty acids, the mass ratio of the palmitic acid to the stearic acid is 1:1-2:1, the polyunsaturated fatty acids are selected from at least one of docosahexaenoic acid, eicosatetraenoic acid and eicosapentaenoic acid, and the mass ratio of the microbial powder to the protective fat is 2:3-3:2. The microbial preparation passing through the rumen described in the application is used as a feed additive for feeding ruminants such as cows, and can realize the dual improvement of the production performance of the cows and the nutrition strengthening of the milk.

Description

Technical Field

[0001] This application relates to the field of animal feed additive technology, and in particular to a rumen-exposed microbial preparation, its preparation method, and its application. Background Technology

[0002] Docosahexaenoic acid (DHA), eicosapentaenoic acid (ARA), and eicosapentaenoic acid (EPA) are long-chain polyunsaturated fatty acids with important physiological functions in the human body. DHA is a structural component of the brain, retina, and nerve tissue, and is crucial for the neurological development and learning and memory formation in infants and young children. DHA deficiency is associated with attention deficit, learning disabilities, and delayed visual development. ARA is an important n-6 polyunsaturated fatty acid required for the development of brain tissue and the immune system in infants and young children, playing a key role in neuronal signaling and immune cell maturation. EPA mainly functions in anti-inflammatory and immunomodulatory aspects, reducing the synthesis of inflammatory mediators (such as prostaglandin E2 and leukotriene B4), and has significant benefits for cardiovascular health. Since the human body's ability to synthesize these fatty acids is limited, they are mainly obtained through dietary intake. Therefore, appropriate supplementation of DHA, ARA, and EPA is an important strategy for improving the nutritional status of pregnant and postpartum women, infant development, and cognitive function in the elderly.

[0003] Milk is one of the most stable sources of animal nutrition in the daily diet of the general public. Enriching milk with DHA, ARA, and EPA can significantly enhance the functionality and added value of dairy products, offering the following advantages: Dairy products have a broad consumer base; dairy products rich in PUFAs (DHA / EPA / ARA) can meet the differentiated nutritional needs of infants, pregnant women, and the elderly at different physiological stages for DHA, ARA, and EPA; both liquid milk and infant formula have a strong demand for enriched polyunsaturated fatty acids, especially in "breast milk equivalence" formulas, where DHA and ARA are essential ingredients; they are more readily accepted than fish oil / algae oil softgels, and dairy products, as food carriers, provide a gentler intake method; and they hold significant commercial potential in the context of the dairy industry's efforts to enhance the differentiated competitiveness of functional products. However, natural milk contains extremely low levels of DHA (<5mg / 100mL), and ARA and EPA are almost undetectable, making it difficult to meet the development needs of functional dairy products. Therefore, it is necessary to increase the level of polyunsaturated fatty acids in milk fat through nutritional regulation.

[0004] Certain microorganisms (such as Schizochytrium and Morphozoa alpineensis) are important sources of functional fatty acids such as DHA, ARA, and EPA, and have been widely studied for improving the reproductive performance of dairy cows, enhancing immunity, and optimizing milk fatty acid composition. However, these polyunsaturated fatty acids are easily hydrogenated by microorganisms in the rumen, resulting in a low proportion of them crossing the rumen and low bioavailability. Based on this, CN112544799B discloses a microalgae whole-cell powder and its preparation method for producing high DHA milk in mammals. Low-melting-point oils (stearic acid or hydrogenated palm oil) are added to antioxidants, phospholipids, crude DHA oil, and bacterial residue under nitrogen protection. The mixture is sheared, mixed, melt-sprayed, cooled, and granulated to prepare rumen-protected Schizochytrium powder, focusing on improving antioxidant protection and rumen-protected stability. CN101912034B discloses a rumen-protected fat, prepared using specific fatty acids (myristic acid C14:0, palmitic acid C16:0, stearic acid C18:0, and oleic acid C18:1), used for nutrient protection. US20210022370A1 discloses a high-oleic acid feedstock for ruminant animals, using a method of adding palmitic acid and / or stearic acid to hydrolyzed high-oleic soybean oil-derived calcium oleate for rumen-protected oleic acid.

[0005] While existing technologies have improved the rumen-passing rate of microalgae fatty acids through optimized encapsulation processes, their solutions have significant drawbacks. Due to the extremely high dietary intake of the required microalgae preparation (typically 300-500 grams per head per day), there is a problem with the effective enrichment of long-chain polyunsaturated fatty acids such as DHA, ARA, and EPA in actual milk. When such a large amount of rumen-passed microalgae preparation is added to the diet as a fat source, focusing solely on the protection efficiency of the target active ingredients (DHA, ARA, EPA) while ignoring the fatty acid composition of the microbial powder or oil used and the protective fat will lead to serious nutritional and metabolic problems in dairy cows. A high proportion of stearic acid (C18:0) in the microalgae oil or protective fat can interfere with normal rumen fermentation, increasing the production of risky intermediate metabolites (such as trans-10 and cis-12 CLA) that inhibit milk fat synthesis (MFD), thereby directly suppressing the fat synthesis function of the mammary glands. This not only leads to a decrease in milk fat percentage and impaired production efficiency, but may also cause energy to be diverted to body fat deposition, thereby affecting the body condition and long-term reproductive performance of dairy cows. Summary of the Invention

[0006] Based on this, it is necessary to provide a rumen-protected algae powder, its preparation method, and its application to address the above-mentioned problems. The rumen-protected algae powder described in this application, when used as a feed additive for feeding dairy cows and other ruminants, can achieve a dual improvement in dairy cow production performance and milk nutritional fortification.

[0007] A rumen-protected microbial preparation includes microbial powder and a coating material covering the surface of the microbial powder, the coating material including protective fat;

[0008] Based on the total weight of fatty acids in the rumen-protected microbial preparation as 100%, the fatty acids include palmitic acid and stearic acid with a total content of 70wt% to 80wt%, oleic acid ≤9wt%, polyunsaturated fatty acids 5wt% to 15wt%, and the balance being non-target fatty acids, wherein the mass ratio of palmitic acid to stearic acid is 1:1 to 2:1, and the polyunsaturated fatty acids are selected from at least one of docosahexaenoic acid, eicosapentaenoic acid, and eicosapentaenoic acid;

[0009] The mass ratio of the microbial powder to the protective fat is 2:3 to 3:2.

[0010] In one embodiment, the microbial powder includes at least one of the following: Schizochytrium powder, Micrococcus pseudocarpa powder, Cryptodinium kurine powder, Diplodocus bisporus powder, and Morphyra alpinea powder.

[0011] In one embodiment, the coating material further includes an antioxidant, the antioxidant having a mass fraction of 0.03% to 0.1% in the rumen-passing microbial preparation.

[0012] In one embodiment, the antioxidant includes at least one of α-tocopherol, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, propyl gallate, tea polyphenols, and rosemary extract.

[0013] In one embodiment, the particle size of the rumen-protected microbial preparation is 100 μm to 1000 μm.

[0014] A method for preparing the rumen-protected microbial preparation as described above includes the following steps:

[0015] Microbial powder is added to the melted protective fat to make an oil suspension;

[0016] The oil suspension is spray-granulated to obtain the rumen-protected microbial preparation.

[0017] In one embodiment, the preparation method satisfies at least one of the following conditions:

[0018] (1) Melting methods include: heating in a water bath at 70℃~80℃;

[0019] (2) Before adding the microbial powder, mix the melted protective fat with the antioxidant;

[0020] (3) When preparing the oil suspension, shearing is performed continuously for 25 min to 35 min under the condition of shear linear velocity of 8.64 m / s to 9.42 m / s.

[0021] In one embodiment, during spray granulation, the granulation blower frequency is 20Hz~40Hz, the granulation induced draft frequency is 30Hz~50Hz, the fluidization blower frequency is 30Hz~50Hz, the fluidization induced draft frequency is 40Hz~50Hz, the spray ring speed is 20rpm~25rpm, the feed speed is 20rpm~100rpm, and the spray ring orifice diameter is 0.7mm~1.0mm.

[0022] A feed comprising a rumen-protected microbial preparation as described above.

[0023] A feed as described above is used to feed ruminants.

[0024] The rumen-protected microbial preparation granules described in this application use microbial powder as the core raw material, with a protective fat coating on the natural cell wall to achieve a double-layer protection of "microbial cell wall + fat encapsulation". At the same time, the overall fatty acid composition of the rumen-protected microalgae preparation is synergistically and precisely optimized. When used as a feed additive for dairy cows and other ruminants, it can be perfectly compatible with animal diets while meeting functional requirements, avoiding side effects such as milk fat synthesis inhibition and reproductive disorders. This achieves a dual improvement in dairy cow production performance and milk nutritional fortification, actively avoiding milk fat synthesis inhibition (MFD) caused by improper stearic acid (C18:0) ratio, which helps maintain the balance between the functionality and safety of feed additives and has strong practical application value. Detailed Implementation

[0025] To facilitate understanding of this application, it will be described in more detail below. However, it should be understood that this application can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments or implementations only and is not intended to be limiting of the application. In this application, when numerical ranges are mentioned, unless otherwise specified, such ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Furthermore, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0027] Through long-term and in-depth research, the applicant has found that the improvement of feed additives for ruminants in the existing technology mainly focuses on protecting DHA so that it can be absorbed smoothly after passing through the rumen to the small intestine. It focuses on optimizing the encapsulation method and generally ignores the influence of the fatty acid composition of the microbial powder itself and the fatty acid composition of the added oil coating material on milk fat synthesis, fat deposition (mammary gland vs. body fat), etc., which leads to an imbalance between the functionality and safety of microbial powder as a feed additive.

[0028] Based on this, this application provides a rumen-protected microbial preparation, including microbial powder and a coating material covering the surface of the microbial powder, wherein the coating material includes protective fat.

[0029] Based on the total weight of fatty acids in the rumen-protected microbial preparation as 100%, the fatty acids include 70wt%~80wt% palmitic acid and stearic acid, ≤9wt% oleic acid, 5wt%~15wt% polyunsaturated fatty acids, and the balance non-target fatty acids, wherein the mass ratio of palmitic acid to stearic acid is 1:1~2:1, and the polyunsaturated fatty acids are selected from at least one of docosahexaenoic acid (DHA), eicosapentaenoic acid (ARA), and eicosapentaenoic acid (EPA); the mass ratio of the microbial powder to the protective fat is 2:3~3:2.

[0030] The rumen-protected microbial preparation granules described in this application use microbial powder as the core raw material, with a protective fat coating on top of the natural cell wall, achieving a double-layer protection of "microbial cell wall + fat encapsulation". By controlling the total content of palmitic acid and stearic acid at 70wt%~80wt% and synergistically regulating their mass ratio at 1:1~2:1, it can efficiently promote milk fat synthesis and increase milk fat percentage while providing excellent product structural stability, avoiding milk fat inhibition, and reducing the risk of abnormal body fat accumulation; oleic acid content ≤9wt% is beneficial to improving fat absorption and membrane fluidity; 5wt%~15wt% of polyunsaturated fatty acids effectively retain and deliver target physiologically active ingredients. In addition, controlling the mass ratio of microbial powder to protective fat at 2:3~3:2 can further optimize milk fat synthesis capacity while achieving the "fat encapsulation" protection of microbial powder functionality, thereby achieving multiple effects such as improved milk production performance and milk quality, stable body condition, and improved breeding efficiency.

[0031] The rumen-protected microbial preparation provided in this application can be used as a feed additive for dairy cows and other ruminants. This allows it to meet functional requirements while being perfectly compatible with animal diets, avoiding side effects such as inhibition of milk fat synthesis and reproductive disorders. This achieves a dual improvement in dairy cow production performance and milk nutritional fortification. It also actively avoids milk fat synthesis inhibition (MFD) caused by improper stearic acid (C18:0) ratio, which helps maintain the balance between the functionality and safety of feed additives and has strong practical application value.

[0032] It should be noted that palmitic acid, stearic acid, oleic acid, and polyunsaturated fatty acids are the target fatty acids in the rumen-protected microbial preparation described in this application; non-target fatty acids refer to other fatty acids in the rumen-protected microbial preparation besides palmitic acid, stearic acid, oleic acid, and polyunsaturated fatty acids, including but not limited to a small amount of other fatty acids generated during microbial fermentation, which are present in low concentrations (usually negligible), and this application does not impose any restrictions on them.

[0033] It is understood that the total content of palmitic acid and stearic acid in the rumen-protected microbial preparation includes, but is not limited to, any one of 70wt%, 72wt%, 75wt%, 78wt%, 80wt%, or any range between the two.

[0034] By synergistically regulating and protecting the ratio of palmitic acid to stearic acid in fat, it is beneficial to further optimize the fatty acid composition of milk fat and avoid problems such as body fat deposition and decreased reproductive performance caused by excessive stearic acid. It has a dual effect of improving nutrition and production performance.

[0035] It is understood that the mass ratio of palmitic acid to stearic acid in the protective fat includes, but is not limited to, any one of the following values ​​or any range between 1:1, 1.2:1, 1.5:1, 1.8:1, and 2:1.

[0036] By synergistically regulating the mass ratio of microbial powder to protective fat, it is beneficial to further optimize and enhance the milk fat synthesis capacity while achieving the functionality of "fat encapsulation" to protect microbial powder, thereby achieving multiple effects such as improved milk production performance and milk quality, stable body condition, and increased breeding efficiency.

[0037] It is understood that the mass ratio of the microbial powder to the protective fat includes, but is not limited to, any one of the following values: 2:3, 5:6, 1:1, 6:5, 3:2, or any range between the two: 2:3, 5:6, 1:1, 6:5, 3:2, or any value ...

[0038] In one embodiment of this application, the microbial powder includes, but is not limited to, at least one of the following: Schizochytrium powder, Micrococcus pseudocarpa powder, Cryptodinium kurine powder, Diplodocus quinquefolius powder, and Morphyra alpineis powder, and may provide at least one of the following components: DNA, ARA, and EPA.

[0039] It should be noted that the protective fats include, but are not limited to, commercially available feed-grade palm fat powder, stearic acid, and oleic acid. Specifically, the palm fat powder contains ≥70wt% palmitic acid (C16:0); the stearic acid contains ≥60wt% stearic acid (C18:0); and the oleic acid contains ≥90wt% oleic acid (C18:1). It is understood that when the palmitic acid content in the palm fat powder is less than 70wt%, the amount of palm fat powder can be increased to ensure that the mass ratio of palmitic acid to stearic acid in the prepared rumen-protected microbial preparation is 1:1 to 2:1. Therefore, this application does not limit the amount or purity of palm fat powder, stearic acid, and oleic acid.

[0040] In one embodiment of this application, the coating material further includes an antioxidant, the antioxidant having a mass fraction of 0.03% to 0.1% in the rumen-passing microbial preparation, which helps to delay the oxidative deterioration of the microbial powder in the rumen-passing microbial preparation, thereby extending the storage time of the rumen-passing microbial preparation.

[0041] It is understood that the mass fraction of the antioxidant in the rumen-passing microbial preparation includes, but is not limited to, any one of 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.1%, or any range between two, preferably 0.05% to 0.07%.

[0042] In one embodiment of this application, the antioxidant includes, but is not limited to, at least one of α-tocopherol, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, propyl gallate, and natural antioxidants, wherein the natural antioxidants include, but are not limited to, tea polyphenols and rosemary extract.

[0043] In one embodiment of this application, the particle size of the rumen-protected microbial preparation is preferably 100μm to 1000μm, including but not limited to at least one of 100μm, 200μm, 500μm, 800μm, and 1000μm, and more preferably 300μm to 1000μm.

[0044] This application provides a method for preparing the rumen-protected microbial preparation as described above, comprising the following steps:

[0045] Microbial powder is added to the melted protective fat to make an oil suspension;

[0046] The oil suspension is spray-granulated to obtain the rumen-protected microbial preparation.

[0047] In one embodiment of this application, the melting method preferably adopts water bath heating. More preferably, the water bath heating temperature is 70°C to 80°C, including but not limited to any one of 70°C, 72°C, 75°C, 78°C, and 80°C, or any range between two of them.

[0048] In one embodiment of this application, the melted protective fat is mixed with an antioxidant before adding the microbial powder.

[0049] In one embodiment of this application, when preparing the oil suspension, the microbial powder is added to the oil phase in small amounts multiple times according to the formula, while stirring. Under the condition of continuous shearing at a shear linear velocity of 8.64m / s to 9.42m / s for 25min to 35min, it is more conducive to the uniform dispersion of microbial powder in fat, forming a stable oil suspension, and promoting the initial infiltration of fat into the cell wall. This avoids problems such as uneven dispersion caused by insufficient shearing, and can also prevent mechanical damage to microbial cells that may be caused by excessive shearing or excessive time.

[0050] In one embodiment of this application, during spray granulation, the granulation blower frequency is 20Hz~40Hz, the granulation induced draft frequency is 30Hz~50Hz, the fluidization blower frequency is 30Hz~50Hz, and the fluidization induced draft frequency is 40Hz~50Hz. This helps to ensure that the material is in a suitable fluidized state in the granulation chamber and also ensures that the material is not pulled away by the induced draft. The spray ring speed is 20rpm~25rpm, the feed speed is 20rpm~100rpm, and the spray ring orifice diameter is 0.7mm~1.0mm.

[0051] This application provides a feed comprising the rumen-protected microbial preparation described above, which can also be used to feed ruminants.

[0052] The rumen-protected microbial powder described in this application, when used as a feed additive for feeding dairy cows and other ruminants, can increase the content of DHA, EPA and / or ARA in milk, while also improving milk fat deposition and fatty acid composition, providing high-quality raw materials for infant formula, maternal dairy products and high-end dairy products.

[0053] It is understood that rumen-protected microbial powder can be mixed with concentrate and then with total mixed ration (TMR) before use, and this application does not impose any restrictions on this.

[0054] The following specific embodiments will further illustrate the rumen-protected microbial preparation, its preparation method, and its application. However, those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0055] Example 1

[0056] 255 kg of palmitic acid, 145 kg of stearic acid, and 50 kg of oleic acid were melt-mixed at 75°C. 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added and completely dissolved. Then, 400 kg of Schizochytrium powder (22% DHA and 38% total fatty acids) was slowly added and sheared continuously for 30 minutes at a shear velocity of 9.0 m / s to form an oil suspension.

[0057] The oil suspension was spray-granulated with the following settings: granulation blower frequency of 32Hz, granulation induced draft frequency of 42Hz, fluidizing blower frequency of 42Hz, fluidizing induced draft frequency of 46Hz, spray ring speed of 22rpm, feed speed of 70rpm, and spray ring orifice diameter of 0.85mm. Particles with a diameter of 100μm~1000μm were collected to obtain a rumen-protected microbial preparation (denoted as sample S1).

[0058] Example 2

[0059] 265 kg of palmitic acid, 144 kg of stearic acid, and 41 kg of oleic acid were melt-mixed at 75°C. 0.8 kg of α-tocopherol was added and completely dissolved. Then, 400 kg of *Micrococcus pluvialis* powder (EPA content 16%, total fatty acid content 27%) was slowly added. The mixture was continuously sheared for 30 min at a shear velocity of 9.0 m / s to form an oil suspension. Spray granulation was performed using the same parameters as in Example 1 to obtain a rumen-protected microbial preparation (denoted as sample S2).

[0060] Example 3

[0061] 231 kg of palmitic acid, 127 kg of stearic acid, and 42 kg of oleic acid were melt-mixed at 75°C. 0.2 kg of α-tocopherol and 0.3 kg of rosemary extract were added and completely dissolved. Then, 400 kg of *Morchella alpina* powder (ARA content 15%, total fatty acid content 24%) was slowly added. The mixture was continuously sheared for 32 min at a shear rate of 9.2 m / s to form an oil suspension.

[0062] The oil suspension was spray-granulated with the following settings: granulation blower frequency 35Hz, granulation induced draft frequency 45Hz, fluidizing blower frequency 45Hz, fluidizing induced draft frequency 48Hz, spray ring speed 23rpm, feed speed 65rpm, and spray ring orifice diameter 0.9mm. Particles with a diameter of 100μm~1000μm were collected to obtain a rumen-protected microbial preparation (denoted as sample S3).

[0063] Example 4

[0064] 294 kg of palmitic acid, 160 kg of stearic acid, and 46 kg of oleic acid were melt-mixed at 75°C. 0.2 kg of α-tocopherol and 0.3 kg of rosemary extract were added and completely dissolved. Then, 150 kg of Schizochytrium powder, 150 kg of Micrococcus pseudocarpa powder, and 100 kg of Morphyra alpineis powder were slowly added. The mixture was continuously sheared for 28 minutes at a shear linear velocity of 8.8 m / s to form an oil suspension.

[0065] The oil suspension was spray-granulated with the following settings: granulation blower frequency 30Hz, granulation induced draft frequency 40Hz, fluidizing blower frequency 40Hz, fluidizing induced draft frequency 45Hz, spray ring speed 22rpm, feed speed 80rpm, and spray ring orifice diameter 0.8mm. Particles with a diameter of 100μm~1000μm were collected to obtain a rumen-protected microbial preparation (denoted as sample S4).

[0066] Example 5

[0067] 281 kg of palmitic acid, 158 kg of stearic acid, and 10 kg of oleic acid were melt-mixed at 70°C. 0.5 kg of α-tocopherol was added and, after complete dissolution, 400 kg of *Schizochytrium* powder was slowly added. The mixture was continuously sheared for 30 minutes at a shear velocity of 9.0 m / s to form an oil suspension. Spray granulation was performed using the same parameters as in Example 1 to obtain a rumen-protected microbial preparation (denoted as sample S5).

[0068] Comparative Example 1

[0069] 450 kg of stearic acid was melt-mixed at 75°C, and 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added. After complete dissolution, 400 kg of Schizochytrium powder (22% DHA content, 38.69% total fatty acids) was slowly added. The mixture was continuously sheared at a shear rate of 9.0 m / s for 30 min to form an oil suspension. Spray granulation was performed using the same parameters as in Example 1 to obtain sample D1.

[0070] Comparative Example 2

[0071] 450 kg of palmitic acid was melt-mixed at 75 °C, and 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added. After complete dissolution, 400 kg of Schizochytrium powder was slowly added. Sample D2 was prepared using the same parameters as Comparative Example 1.

[0072] Comparative Example 3

[0073] 400 kg of palmitic acid and 50 kg of oleic acid were melt-mixed at 75°C. 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added and completely dissolved. Then, 400 kg of Schizochytrium powder was slowly added. Sample D3 was prepared using the same parameters as Comparative Example 1.

[0074] Comparative Example 4

[0075] 400 kg of stearic acid and 50 kg of oleic acid were melt-mixed at 75°C, and 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added. After complete dissolution, 400 kg of Schizochytrium powder was slowly added. Sample D4 was prepared using the same parameters as Comparative Example 1.

[0076] Comparative Example 5

[0077] 200 kg of palmitic acid, 220 kg of stearic acid, and 50 kg of oleic acid were melt-mixed at 75°C. 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added and completely dissolved. Then, 400 kg of Schizochytrium powder was slowly added. Sample D5 was prepared using the same parameters as Comparative Example 1.

[0078] Comparative Example 6

[0079] 255 kg of palmitic acid, 145 kg of stearic acid, and 50 kg of linseed oil were melt-mixed at 75°C. 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added and completely dissolved. Then, 400 kg of Schizochytrium powder was slowly added. Sample D6 was prepared using the same parameters as Comparative Example 1.

[0080] Comparative Example 7

[0081] 235 kg of palmitic acid, 145 kg of stearic acid, 50 kg of oleic acid, and 20 kg of myristic acid were melt-mixed at 75°C. 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added and completely dissolved. Then, 400 kg of Schizochytrium powder was slowly added. Sample D7 was prepared using the same parameters as Comparative Example 1.

[0082] Comparative Example 8

[0083] 260 kg of palmitic acid, 120 kg of stearic acid, and 50 kg of oleic acid were melt-mixed at 75°C. 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added and completely dissolved. Then, 400 kg of Schizochytrium powder was slowly added. Sample D8 was prepared using the same parameters as Comparative Example 1.

[0084] Comparative Example 9

[0085] 110 kg of palmitic acid, 70 kg of stearic acid, and 20 kg of oleic acid were melt-mixed at 75°C. Then, 0.4 kg of α-tocopherol and 0.4 kg of butylated hydroxytoluene were added and completely dissolved. Finally, 400 kg of *Cryptodinium clarithii* powder was slowly added. Due to the further increase in solid content, the mixture was continuously sheared at a shear velocity of 9.4 m / s for 35 minutes to form an oil suspension.

[0086] The oil suspension was spray-granulated with the following settings: granulation blower frequency 38Hz, granulation induced draft frequency 48Hz, fluidization blower frequency 48Hz, fluidization induced draft frequency 50Hz, spray ring speed 24rpm, feed speed 40rpm, and spray ring orifice diameter 0.95mm. Particles with a diameter of 100μm~1000μm were collected to obtain sample D9.

[0087] Comparative Example 10

[0088] 360 kg of palmitic acid, 226 kg of stearic acid, and 64 kg of oleic acid were melt-mixed at 75°C. Then, 0.4 kg of α-tocopherol and 0.4 kg of rosemary extract were added and completely dissolved. Finally, 400 kg of Schizochytrium powder was slowly added. Due to the reduced solid content and high oil phase ratio, a shear rate of 8.6 m / s (the lower limit of the standard) was applied for 26 minutes to form an oil suspension.

[0089] The oil suspension was spray-granulated with the following settings: granulation blower frequency 25Hz, granulation induced draft frequency 35Hz, fluidization blower frequency 35Hz, fluidization induced draft frequency 42Hz, spray ring speed 20rpm, feed speed 90rpm, and spray ring orifice diameter 0.75mm. Particles with a diameter of 100μm~1000μm were collected to obtain sample D10.

[0090] The fatty acid composition of all rumen-protected microbial preparations prepared in the examples and comparative examples was determined, with the total weight of non-target fatty acids and target fatty acids listed in Table 1 being 100%. The results are shown in Table 1.

[0091] Table 1

[0092]

[0093] Application examples

[0094] Three hundred and fifty-seven healthy dairy cows of similar age, parity, and lactation days were randomly divided into 17 groups of 21 cows each (control group, Example 1-8 groups, and Comparative Examples 1-8 groups). The pre-feeding period was 15 days, and the formal feeding period was 60 days. Each cow was fed 300g of rumen-exposed microbial powder daily, three times a day with pasture feed, 100g each time. At the end of the formal feeding period, milk samples from each group were collected daily for testing milk fat, DHA, EPA, ARA, and oleic acid content. After discontinuing rumen-exposed microbial supplementation, the cows' body condition scores at 150 days of lactation and their conception rate after their first mating were recorded. The results are shown in Tables 2, 3, and 4.

[0095] Table 2

[0096]

[0097] Table 3

[0098]

[0099] Table 4

[0100]

[0101] As shown in Tables 1 to 4, different sources of fatty acids and the composition of carrier fatty acids have a significant impact on the deposition effect of polyunsaturated fatty acids in dairy cow milk fat, dairy product quality, and reproductive performance.

[0102] As shown in Table 2, the positive example groups (S1-S5) exhibited balanced and excellent performance in four aspects: synergistic enhancement of palmitic acid / stearic acid in milk fat, moderate reduction of oleic acid, efficient deposition of target PUFAs, and optimization of the n-6 / n-3 ratio. This confirms that the fatty acid composition and ratio specified in this application have a complete physiological synergistic effect. Comparative examples D8-D10 show that if the ratio of palmitic acid to stearic acid exceeds 2:1 or the ratio of microbial powder to protective fat exceeds 2:3-3:2, even if other indicators are qualified, it will still lead to a significant decrease in milk fat synthesis efficiency or PUFA deposition rate. Comparative examples D1-D7 further reveal that palmitic acid and stearic acid must coexist, their total amount must be dominant, oleic acid must be strictly controlled, and PUFAs must be precisely measured. The absence or deviation of any element will induce an imbalance in milk fat metabolism.

[0103] As shown in Table 3, the positive example groups (S1~S5) were significantly better than the blank group and all comparative groups in terms of the three core milk quality indicators: milk fat percentage, milk protein percentage, and total milk solids. This reflects the synergistic effect of the complete combination of technical characteristics on the production performance of ruminants: total palmitic acid and stearic acid of 70%~80%, their ratio of 1:1~2:1, oleic acid ≤9%, PUFA 5%~15%, and the ratio of microbial powder to protective fat of 2:3~3:2. Any deviation from any single characteristic will lead to a significant weakening or loss of the milk quality improvement effect.

[0104] As shown in Table 4, the positive example groups (S1~S5) were significantly superior to the blank group and all comparative groups in all dimensions of reproductive indicators, including body condition maintenance, postpartum estrus recovery, conception rate, and cumulative pregnancy rate. This fully demonstrates that the complete combination of technical features specified in this application—70-80% total palmitic acid and stearic acid, a ratio of 1:1 to 2:1, oleic acid ≤9%, PUFA 5-15%, and a ratio of microbial powder to protective fat of 2:3 to 3:2—can: effectively alleviate the negative energy balance in early lactation (BCS increase of 0.25-0.35); accelerate postpartum reproductive function recovery (first insemination 12-15 days earlier); significantly improve conception efficiency (total conception rate increased by 10.8-14.4 percentage points, and the number of inseminations reduced by 0.7-0.9 times); and achieve a shortened reproductive cycle (conception rate increased by 15.0-19.9 percentage points within 150 days).

[0105] Comparative Examples D8-D10 show that when the ratio of palmitic acid to stearic acid exceeds 2:1 or the ratio of microbial powder to protective fat exceeds 2:3-3:2, the improvement in reproductive performance is significantly weakened even if other indicators meet the requirements, proving that these two ratio limits are irreplaceable. Comparative Examples D1-D7 further reveal that palmitic acid and stearic acid must coexist and constitute the majority in total, oleic acid must be strictly controlled, and PUFA must be precisely measured. The absence or deviation of any of these elements will lead to varying degrees of loss in reproductive performance.

[0106] In summary, the rumen-protected microbial preparation described in this application achieves a synergistic improvement in four dimensions: lactation performance, milk quality, body condition maintenance, and reproductive efficiency through systematic optimization of fatty acid composition and ratio. It is a typical example of a comprehensive solution in the field of ruminant nutrition.

[0107] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A rumen-exposed microbial preparation, characterized in that, It includes microbial powder and a coating material covering the surface of the microbial powder, the coating material including protective fat; Based on the total weight of fatty acids in the rumen-protected microbial preparation as 100%, the fatty acids include palmitic acid and stearic acid with a total content of 70wt% to 80wt%, oleic acid ≤9wt%, polyunsaturated fatty acids 5wt% to 15wt%, and the balance being non-target fatty acids, wherein the mass ratio of palmitic acid to stearic acid is 1:1 to 2:1, and the polyunsaturated fatty acids are selected from at least one of docosahexaenoic acid, eicosapentaenoic acid, and eicosapentaenoic acid; The mass ratio of the microbial powder to the protective fat is 2:3 to 3:

2.

2. The rumen-protected microbial preparation according to claim 1, characterized in that, The microbial powder includes at least one of the following: Schizochytrium powder, Micrococcus pseudocarpa powder, Cryptodinium kurine powder, Diplodocus bisporus powder, and Morphyra alpineis powder.

3. The rumen-protected microbial preparation according to claim 1, characterized in that, The coating material also includes an antioxidant, the antioxidant having a mass fraction of 0.03% to 0.1% in the rumen-passing microbial preparation.

4. The rumen-protected microbial preparation according to claim 3, characterized in that, The antioxidants include at least one of α-tocopherol, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, propyl gallate, tea polyphenols, and rosemary extract.

5. The rumen-protected microbial preparation according to claim 1, characterized in that, The particle size of the rumen-protected microbial preparation is 100μm~1000μm.

6. A method for preparing a rumen-crossed microbial preparation as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Microbial powder is added to the melted protective fat to make an oil suspension; The oil suspension is spray-granulated to obtain the rumen-protected microbial preparation.

7. The method for preparing the rumen-exposed microbial preparation according to claim 6, characterized in that, At least one of the following conditions must be met: (1) Melting methods include: heating in a water bath at 70℃~80℃; (2) Before adding the microbial powder, mix the melted protective fat with the antioxidant; (3) When preparing the oil suspension, shearing is performed continuously for 25 min to 35 min under the condition of shear linear velocity of 8.64 m / s to 9.42 m / s.

8. The method for preparing the rumen-passing microbial preparation according to claim 6, characterized in that, During spray granulation, the granulation blower frequency is 20Hz~40Hz, the granulation induced draft frequency is 30Hz~50Hz, the fluidization blower frequency is 30Hz~50Hz, the fluidization induced draft frequency is 40Hz~50Hz, the spray ring speed is 20rpm~25rpm, the feed speed is 20rpm~100rpm, and the spray ring orifice diameter is 0.7mm~1.0mm.

9. A feed, characterized in that, Including the rumen-protected microbial preparations as described in any one of claims 1 to 5.

10. A feed as described in claim 9 for feeding ruminants.

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