Animal feed as well as preparation method and optimization method thereof

Abstract

The invention relates to the technical field of animal feeds, and provides an animal feed and a preparation method and optimization method thereof, and the optimization method of the animal feed comprises the following steps: determining candidate microorganisms and nutrition raw material formulas, establishing an optimization model, and solving to obtain an optimal microorganism formula and an optimal nutrition raw material formula; the animal feed comprises microorganisms such as lactic acid bacteria, saccharomycetes and bacillus and nutritional raw materials such as corn and soybean meal. By adopting a multilayer microcapsule technology, the survival rate of microorganisms in an acid environment is improved, the digestion and absorption efficiency is improved, and the nutritional condition and the milk production performance are improved; the invention further provides a corresponding preparation method, and the feed has the remarkable slow release characteristic and the effect of improving the feed utilization rate.

Description

Technical Field

[0001] The present invention relates to the technical field of animal feed, and more particularly to an animal feed, a preparation method thereof and an optimization method thereof. Background Art

[0002] The development of animal feed technology has always been one of the key issues in animal husbandry. Reasonable feed formula can not only meet the nutritional needs of animals and promote growth and development, but also improve feed utilization and reduce feeding costs. Therefore, it is of great significance to research and develop nutritionally balanced, easy to digest and absorb animal feed and its preparation method.

[0003] The Chinese patent application with publication number CN118000289A discloses an animal feed additive and a preparation method thereof. The additive uses composite fungus residue, soy protein powder and other raw materials, and by adding nutrients such as vitamins and trace elements, increases the digestive capacity of animals and the utilization of feed, thereby promoting the growth and development of animals. However, the technical solution does not involve how to optimize the ratio of microbial strains in feed, nor does it consider the effect of the acidic environment of gastric juice on microbial activity. Therefore, further research is needed to improve the survival rate and metabolic activity of microorganisms in animals.

[0004] A Chinese patent with the authorization announcement number CN110384177B discloses a method for preparing yeast culture based on distiller's grains and its application in animal feed. This method uses distiller's grains as raw materials and prepares yeast culture rich in nutrients such as vitamins through a solid-state fermentation process, which can be used as a feed additive to enhance the nutritional value of feed. However, this technical solution does not involve how to protect the activity of yeast in the acidic environment of the animal's stomach, nor does it optimize the ratio of yeast to other microorganisms and nutritional raw materials. Therefore, further research is needed on microencapsulation technology to improve the survival rate of microorganisms such as yeast in the body, as well as methods to optimize the ratio of multiple microorganisms to nutritional raw materials.

[0005] In summary, some nutritionally balanced animal feed formulas have been proposed in the prior art, but they still have shortcomings in terms of increasing the survival rate of microorganisms in an acidic environment and improving the release and absorption of nutrients. Summary of the invention

[0006] In view of this, one purpose of the present application is to provide a method for optimizing animal feed, optimizing the feed formula according to the characteristics of the animal's stomach environment, protecting the survival of microorganisms in acidic gastric juice through multi-layer microcapsule encapsulation technology, and gradually releasing nutrients in the stomach, thereby improving the digestion and absorption efficiency of feed and improving the nutritional status and milk production performance of animals.

[0007] Another object of the present application is to provide an animal feed.

[0008] Another object of the present application is to provide a method for preparing animal feed.

[0009] To achieve the above objectives, the first aspect of the present application proposes a method for optimizing animal feed, comprising:

[0010] Determine candidate microbial formulas and nutrient raw material formulas, and establish candidate microbial formula sets and candidate nutrient raw material formula sets;

[0011] A feed formula optimization model was established using feed formula including microbial formula and nutrient raw material formula as decision variables;

[0012] Solve the feed formula optimization model and obtain the optimal microbial formula and the optimal nutritional raw material formula from the candidate microbial formula set and the candidate nutritional raw material formula set.

[0013] In some embodiments, the feed formula optimization model consists of three parts: objective function, constraints, and decision variables; the objective function includes a microbial activity objective function, a nutrient absorption rate objective function, and a feed cost objective function; the constraints include ratio constraints, nutrient raw material dosage constraints, microbial viable count constraints, nutrient absorption rate constraints, and cost constraints.

[0014] Preferably, the microbial activity objective function calculates the microbial activity index based on the number of viable microorganisms, the content of key nutrients and the utilization rate of key nutrients by microorganisms, and finds the maximum value of the microbial activity index; the nutrient absorption rate objective function finds the maximum value based on the weighted nutrient absorption rate; the feed cost objective function is based on the feed cost, feed characteristic function indicators and the economic value coefficient of feed characteristic functions, and calculates the feed cost index through a ratio function to find the minimum value of the feed cost index.

[0015] Preferably, the ratio constraint is that the sum of the mass fractions of all nutrients in the nutrient raw material formula is 1; the nutrient raw material dosage constraint is that the addition amount of the kth nutrient raw material is greater than or equal to the minimum addition amount of the kth nutrient raw material, and less than or equal to the maximum addition amount of the kth nutrient raw material, k = 1, 2, ..., p, p is the total number of nutrient raw materials; the viable microbial count constraint is that the viable count of the ith microorganism is greater than or equal to the minimum viable count requirement of the ith microorganism, i = 1, 2, ..., m, m is the total number of microbial species; the cost constraint is that the feed cost is less than or equal to the upper limit of the feed cost; the nutrient absorption rate constraint is that the absorption rate of the jth key nutrient is greater than or equal to the difference between the minimum absorption rate requirement of the jth key nutrient and the temperature deviation term, the pH deviation term and the microbial regulation term.

[0016] In some embodiments, the microorganisms in the optimal microbial formula include at least three types: lactic acid bacteria, yeast, and bacillus; the optimal nutritional raw material formula includes at least corn, soybean meal, bran, fish meal, yeast powder, vitamin premix, and mineral premix;

[0017] Preferably, in terms of mass percentage, the optimal microbial formula is 40%-60% lactic acid bacteria, 20%-40% yeast, and 10%-30% bacillus, with lactic acid bacteria accounting for the highest proportion; the lactic acid bacteria are one or more of Lactobacillus rhamnosus and Lactobacillus casei; the yeast are one or more of Candida and KF-7 yeast; the bacillus are one or more of Bacillus licheniformis and Lactobacillus acidophilus; the nutritional raw material formula is, in terms of mass percentage, 40%-60% corn, 20%-30% soybean meal, 5%-15% bran, 3%-8% fish meal, 1%-5% yeast powder, 0.1%-0.5% vitamin premix, and 0.5%-1.5% mineral premix.

[0018] More preferably, the optimal microbial formula is, by mass percentage, 60% of Lactobacillus rhamnosus, 15% of Candida, 15% of KF-7 yeast, and 10% of Lactobacillus acidophilus; the nutritional raw material formula is, by mass percentage, 45% of corn, 30% of soybean meal, 15% of bran, 4.2% of fish meal, 5% of yeast powder, 0.2% of vitamin premix, and 0.6% of mineral premix.

[0019] The second aspect of the present application proposes an animal feed, comprising a microbial component, a nutritional raw material component and a multilayer microcapsule; the microbial component adopts an optimal microbial formula obtained by an optimization method, and the nutritional raw material component adopts an optimal nutritional raw material formula obtained by an optimization method.

[0020] In some embodiments, the multilayer microcapsule comprises three layers: a load core, a buffer layer and a sustained-release shell. The material used for the load core comprises a load core material 1 and a load core material 2. The buffer layer is made of a buffer layer material. The sustained-release shell is made of a sustained-release shell material. The load core is used to load the microbial components in animal feed.

[0021] In some embodiments, the first load core material includes sodium alginate; the second load core material includes at least one of chitosan and gelatin; the buffer layer material includes at least citric acid and sodium bicarbonate; the sustained-release shell material includes at least one of pH-sensitive polymer, HPMCAS, and guar gum;

[0022] In some embodiments, the multilayer microcapsules have an average particle size of 100-500 μm.

[0023] The third aspect of the present application provides a method for preparing animal feed, comprising:

[0024] Microbial fermentation: lactic acid bacteria, yeast, and bacillus were inoculated into MRS medium, YPD medium, and NB medium, respectively, and fermented at 37°C for 24-48 hours. The microbial cells were collected by centrifugation and washed;

[0025] Preparation of microcapsules: preparing microbial cells according to the optimal microbial formula, and then evenly mixing the microbial cells with the solution configured by the load core material one to prepare the load core microspheres; then placing the load core microspheres in the solution configured by the load core material two, forming a coating of the load core material two on the surface of the load core microspheres, and obtaining pre-coated load core microspheres; then, soaking the pre-coated load core microspheres in the solution configured by the buffer layer material, and forming a pH buffer layer around the load core microspheres; finally, dissolving the sustained-release shell material in an organic solvent, and coating the surface of the microspheres with a uniform and dense enteric shell, and obtaining multi-layer microcapsules with a multi-layer structure;

[0026] Mixing nutrient raw materials with microorganisms: crushing and sieving the nutrient raw materials, and mixing them according to the ratio of the optimal nutrient raw material formula; then adding multi-layer microcapsules, and continuing to mix evenly to obtain animal feed powder;

[0027] Granulation: Press the animal feed powder into granules with a particle size of 2-5mm.

[0028] The animal feed optimization method of the present application can at least bring the following beneficial effects:

[0029] By using multi-layer microcapsule technology, effective protection of microorganisms in an acidic environment is achieved, thereby improving their survival rate. This technology ensures the gradual release of feed in the animal's stomach and improves the efficiency of digestion and absorption. Through the scientific selection and proportioning of microbial strains and nutritional raw materials, the optimization method can provide the energy, protein and trace elements required by animals in a comprehensive and balanced manner. In addition, by comprehensively considering microbial activity, nutrient absorption rate and cost through the optimization model, production performance can be significantly improved within an economically feasible range and overall feed costs can be reduced.

[0030] The animal feed described in this application can at least bring the following beneficial effects:

[0031] By improving the gastrointestinal health and nutrient absorption efficiency of animals, the milk production and quality of animals are significantly improved. Metabolites such as lactic acid and short-chain fatty acids in the feed can effectively improve the rumen environment, enhance the disease resistance of animals, and prolong their peak milk production period. In addition, this feed is rich in prebiotics and bioactive substances, which can replace traditional antibiotic drug additives and reduce the risk of drug residues, thereby producing safer and healthier milk, further improving product safety and added value.

[0032] The method for preparing the animal feed of the present application, in addition to the beneficial effects of the animal feed of the embodiment of the present application, can also bring at least the following beneficial effects:

[0033] The preparation method of animal feed adopts modern microcapsule preparation technology, such as emulsification-coagulation-spray drying technology, which greatly improves the survival rate of microorganisms during feeding and reduces the loss of microorganisms during breeding. The multi-layer structure design of microcapsules gives the product significant sustained-release characteristics, avoiding the sudden release of core substances, and maintaining a stable number of probiotics and continuous nutrient supply in the gastrointestinal tract. The advanced preparation technology has laid a solid foundation for the industrial application of animal feed, and through optimized combination, it has significantly improved feed utilization, improved the gastrointestinal health of animals, and ultimately effectively improved the production performance of animals.

[0034] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 is a flow chart of the method for optimizing animal feed in the present invention;

[0037] Figure 2 It is a schematic diagram of the structure of multilayer microcapsules in animal feed of the present invention;

[0038] Figure 3 The figure is a principle flow chart of the method for preparing animal feed in the present invention.

[0039] In the figure, 10-loaded core, 20-buffer layer, 30-slow-release shell. DETAILED DESCRIPTION

[0040] The embodiments of the present application are described in detail below. The embodiments are exemplary and intended to be used to explain the present application, but should not be construed as limiting the present application.

[0041] In this application, the disclosure of numerical ranges includes all values ​​within the entire range and the disclosure of further subdivided ranges, including the endpoints and sub-ranges given in these ranges.

[0042] In this application, the raw materials, equipment, etc. involved, unless otherwise specified, are all raw materials and equipment that can be made through commercial channels or known methods; the methods involved, unless otherwise specified, are all conventional methods.

[0043] The embodiments of the present application are intended to optimize the animal feed formula according to the characteristics of the animal stomach environment, and to protect the survival of microorganisms in acidic gastric juice through multi-layer microcapsule encapsulation technology, thereby improving the digestion and absorption efficiency of feed and improving the nutritional status and milk production performance of animals.

[0044] Specifically, by selecting appropriate microbial strains and their combinations, optimizing the ratio of microorganisms to nutrient raw materials, and using multi-layer microcapsule technology to ensure the sustained release of microorganisms in the stomach, protect the microorganisms, and gradually release them in an acidic environment, thereby improving digestion and absorption efficiency. The screening of microbial strains is based on their colonization ability in the stomach, enzyme activity, and nutrient production capacity. The nutrient raw material formula focuses on the balance of carbon-nitrogen ratio, trace elements, and growth factors to provide optimal conditions for the growth and metabolism of microorganisms. Multi-layer microcapsule encapsulation technology protects the survival of microorganisms in an acidic environment and achieves controlled release of nutrients, thereby improving the digestion and absorption efficiency and milk production performance of animals.

[0045] The animal feed optimization method, animal feed, animal feed preparation method, etc. of the present application are described in detail below.

[0046] The method for optimizing animal feed in the embodiment of the present application is as follows: Figure 1 As shown, the following steps are included:

[0047] S101. Determine candidate microbial formulas and nutrient raw material formulas, and establish a candidate microbial formula set and a candidate nutrient raw material formula set.

[0048] Screen the microorganisms and nutritional raw materials that can be used for animal feed from the alternative microbial strains and alternative nutritional raw materials, determine the candidate microbial formulas and nutritional raw material formulas, and establish a candidate microbial formula set and a candidate nutritional raw material formula set; the purpose of this step is to preliminarily determine some microbial strains that may be used and their ratios, as well as the types and mass fraction ranges of nutritional raw materials, to provide a basis for subsequent optimization.

[0049] Alternative microbial strains refer to candidate beneficial strains for fermentation. They are usually screened based on their colonization ability in the animal intestine, enzyme production activity, antibacterial spectrum and other characteristics. Common alternative microbial strains include lactic acid bacteria, yeast and Bacillus; lactic acid bacteria can produce lactic acid, lower intestinal pH, and inhibit the growth of harmful bacteria. Representative strains include Lactobacillus rhamnosus and Lactobacillus casei; yeast can produce a variety of enzymes and bioactive substances, improve intestinal microecology, and representative strains include Candida, KF-7 yeast, etc.; Bacillus can form heat-resistant and acid-resistant spores and can survive in adverse environments. Representative strains include Bacillus licheniformis and Lactobacillus acidophilus, etc.

[0050] Alternative nutritional raw materials refer to candidate feed raw materials for providing the nutrients required by animals, and are usually screened based on their nutritional composition, digestibility, palatability and other characteristics; common alternative nutritional raw materials include energy feed, protein feed and trace nutrient additives; energy feed such as corn, soybean meal, bran, etc. mainly provide energy and protein; protein feed such as fish meal, yeast powder, etc., provide protein, among which fish meal and yeast powder are high-quality proteins; trace nutrient additives such as vitamin premixes (VA, VD, VE, etc.) and mineral premixes (Ca, P, Fe, Cu, Zn, Mn, etc.) are necessary to maintain the normal physiological functions of the body and need to be added but in smaller amounts.

[0051] The candidate microbial formula includes the microbial species and the added proportion of various types of microorganisms. For example, by mass percentage, lactic acid bacteria account for 50%-80%, yeast accounts for 25%-55%, and Bacillus accounts for 5%-10%; the candidate nutritional raw material formula includes the types of nutritional raw materials and the mass fraction of each type of nutritional raw materials in all nutritional raw materials, for example, corn 45%-70%, soybean meal 10%-20%, bran 5%-10%, fish meal 8%-15%, yeast powder 3%-8%, vitamin premix 0.4%-1.0%, and mineral premix 1.1%-2.8%.

[0052] The candidate microbial formula set includes candidate microbial formulas for animal feed, and the candidate nutrient raw material formula set includes candidate nutrient raw material formulas for animal feed. The candidate microbial formula set and the candidate nutrient raw material formula set limit the possible microbial strains, nutrient raw materials and their ratio ranges, reduce the optimization search space, and improve the optimization efficiency; through the screening of candidate microorganisms and nutrient raw materials, some strains and raw materials with poor effects or unsuitable effects are eliminated, ensuring the effectiveness and safety of the feed; considering the microbial formula and nutrient raw material formula separately, on the one hand, conforms to the general process of feed formula design, on the other hand, it also provides the possibility for independent optimization of the two, increasing flexibility; in short, step S102 simplifies the problem to a certain extent by establishing the candidate microbial formula set and the candidate nutrient raw material formula set, laying the foundation for subsequent formula optimization, and these candidate formulas can be regarded as alternative solutions to the optimization problem, and the final optimal solution will be generated from them.

[0053] S102. Establish a feed formula optimization model using the feed formula including the microbial formula and the nutrient raw material formula as decision variables.

[0054] In the embodiment of the present application, the feed formula optimization model consists of three parts: objective function, constraint conditions, and decision variables;

[0055] In an embodiment of the present application, the objective function includes a microbial activity objective function, a nutrient absorption rate objective function, and a feed cost objective function;

[0056] In the embodiment of the present application, the microbial activity objective function is based on the number of viable microorganisms, the content of key nutrients and the utilization rate of key nutrients by microorganisms to calculate the microbial activity index and find the maximum value of the microbial activity index;

[0057] In an embodiment of the present application, the nutrient absorption rate objective function seeks the maximum value based on the weighted nutrient absorption rate;

[0058] In the embodiment of the present application, the feed cost objective function is based on the feed cost, the feed characteristic function index and the economic value coefficient of the feed characteristic function, and the feed cost index is calculated through the ratio function to find the minimum value of the feed cost index;

[0059] The feed formulation optimization model is established comprising:

[0060] Identify the decision variables:

[0061] Assume feed formula x = (x 1 ,x 2 ,...,x N ), the feed formula includes microbial formula and nutrient raw material formula, and the feed formula x is used as the decision variable, where x q(q=1,2,...,N) is the qth decision variable, and N is the total number of decision variables.

[0062] Construct the objective function:

[0063] (1) Microbial activity objective function

[0064]

[0065] in:

[0066] f 1 (x): microbial activity index;

[0067] m: total number of microbial species;

[0068] a i : is the importance weight coefficient of the i-th microorganism, reflecting its role in the fermentation process, which can be determined by expert judgment or hierarchical analysis method, i = 1, 2, ..., m;

[0069] V i (x): viable count of the i-th microorganism (cfu / g);

[0070] G i (T i ,pH i ,C i ) is the environmental factor function that affects the growth of the i-th microorganism, T i is temperature, pH i is pH value, C i is the concentration of key nutrients, which can be obtained through experimental determination or literature review;

[0071] b i : is the utilization coefficient of the i-th microorganism for key nutrients, reflecting its sensitivity to nutrition, which can be obtained through regression analysis fitting;

[0072] d ij : is the correlation between the i-th microorganism and the j-th key nutrient, reflecting the influence of nutrients on microbial growth, which can be obtained by using the grey correlation analysis method; j = 1, 2, ..., n, n is the total number of key nutrients;

[0073] N j : is the content of the jth key nutrient;

[0074] The number of viable microorganisms represents the number of surviving probiotic microbial colonies in the feed (cfu / g), and is an important indicator for measuring microbial activity. The higher the number of viable microorganisms, the better the probiotic effect. In the microbial activity objective function, the more viable microorganisms there are, the higher the microbial activity index is. The utilization rate of key nutrients such as protein, fat, vitamins, etc. by microorganisms is i , which reflects the ability of probiotic microorganisms to promote host digestion and absorption, is another important indicator for measuring microbial activity. The higher the microbial utilization rate, the more effectively they can decompose and transform the nutrients in the feed, thereby improving the efficiency of animal absorption of nutrients. i When the index is larger, that is, the microorganism has a higher utilization rate of nutrients, the increase in the content of key nutrients will more obviously enhance the microbial activity, making the index item The value is closer to 1, thereby increasing the microbial activity index f 1 (x). On the contrary, if b i If the value is smaller, it means that the microorganism has a weak ability to utilize nutrients. Even if the content of key nutrients is increased, it is difficult to significantly improve the activity of the microorganism. The value of the index item will be closer to 0. The microbial activity index f 1 (x) The impact is limited.

[0075] The objective function of microbial activity is introduced into G i (T i ,pH i ,C i ) is because the growth and reproduction of microorganisms are significantly affected by environmental conditions such as temperature, pH value, and nutrient concentration; specifically, each microorganism has a temperature range suitable for growth. When the ambient temperature deviates from this range, the growth rate and metabolic activity of the microorganism will significantly decrease. Therefore, the temperature factor has an important regulatory effect on microbial activity; the growth of microorganisms is also sensitive to pH value. Most microorganisms are suitable for growth under neutral or weakly acidic conditions, while overly acidic or alkaline environments will inhibit their growth. By introducing the pH value factor, the effect of pH changes on microbial activity during feed fermentation can be measured; the growth and reproduction of microorganisms requires the consumption of certain nutrients, such as carbon sources, nitrogen sources, minerals, etc. When nutrients are insufficient, the growth of microorganisms will be restricted. The nutrient concentration can reflect the restrictive effect of the abundance and deficiency of various nutrients in the culture medium on the activity of microorganisms. G i (T i ,pH i ,C i) can usually be described by some empirical models or regression equations, such as the Arrhenius equation, the Michaelis-Menten equation, etc., or can be fitted by experimental data. When certain components in the feed formula change, such as the type of carbon source, the amount of additives, etc., it will affect the temperature, pH value and nutrient concentration of the culture medium, and then through G i (T i ,pH i ,C i ) indirectly affects the microbial activity, therefore, the introduction of this function can more accurately evaluate the effect of formulation changes on microbial growth.

[0076] Another important parameter in the formula is the nutrient content N j The growth and metabolism of microorganisms cannot be separated from the supply of nutrients. j The size of N directly determines the amount of nutrient substrate available to microorganisms. When the content of key nutrients such as protein, minerals, vitamins, etc. in the feed formula increases, j The value of will increase, and the microorganisms will have more "food" to maintain their life activities, thereby improving the activity of the population. The form of can be regarded as a "nutrient utilization saturation function". j When it is very small, microbial activity is more sensitive to it. j A small increase in N can significantly promote microbial growth; however, j After exceeding a certain threshold, the growth rate of microbial activity will gradually slow down and tend to stabilize. This nonlinear relationship conforms to the general law of biological growth.

[0077] The microbial activity objective function mainly characterizes the effects of the microorganisms in the feed formula x and the key nutrients in the nutrient raw materials on the microbial fermentation performance. Specifically, The sum of the activities of m kinds of microorganisms is considered in part, which comprehensively reflects the fermentation promotion effect of feed formula x under different microbial growth requirements and environmental conditions. By optimizing the microbial activity index, the survival rate of microorganisms in the animal stomach can be significantly improved, especially in an acidic environment, which ensures that more microorganisms can play an effective role. Secondly, microorganisms with higher activity can more effectively decompose nutrients in feed, thereby improving nutrient absorption rate, improving the nutritional status and milk production performance of animals. In addition, active microorganisms help maintain the balance of intestinal flora, inhibit the growth of harmful bacteria, improve the overall health of animals, and reduce the risk of disease. Finally, by improving microbial activity, the nutrients in feed can be more fully utilized, waste can be reduced, and the cost-effectiveness of feed can be improved. These effects work together to comprehensively improve the nutritional status and production performance of animals.

[0078] (2) Nutrient absorption rate objective function

[0079]

[0080] Among them, f 2 (x) is the nutrient absorption rate, A j (x) is the actual absorption rate of the jth key nutrient, s j A j (x) is the weight coefficient, n is the total number of key nutrients, j = 1, 2, ..., n; nutrient absorption rate refers to the degree of digestion and absorption of each nutrient in the feed by the animal, which affects the feed utilization efficiency and animal production performance; the target value of nutrient absorption rate is 60%-90%, including but not limited to 60%, 70%, 80% or 90%, etc. If the target value of nutrient absorption rate is lower than 60%, it means that the feed utilization rate is low and the nutritional value is poor; if it is higher than 90%, although the feed quality is excellent, the formula cost may be high. The nutrient absorption rate objective function characterizes the degree of digestion and absorption of each nutrient in the feed by the animal, A j The higher (x), the higher the feed utilization rate; the total number of key nutrients includes carbohydrates, proteins, fats, minerals, vitamins, etc.

[0081] The digestion and absorption capacity of animals for nutrients will affect their growth, milk production, health level and other traits. Therefore, taking the nutrient absorption rate as one of the optimization goals and seeking the optimal formula through mathematical modeling can maximize the efficiency of nutrient utilization and meet the nutritional needs of animal production; by maximizing the nutrient absorption rate, the digestion and absorption efficiency of various nutrients in the feed, such as protein, fat, minerals, vitamins, etc., can be improved, and nutrient loss can be reduced, thereby improving the nutritional status of animals and improving production performance.

[0082] (3) Feed cost objective function

[0083]

[0084] in:

[0085] f 3 (x): feed cost index;

[0086] p: total number of nutrient raw materials;

[0087] c k : is the unit price of the kth nutrient raw material, k = 1, 2, ..., p;

[0088] W k (x): the amount of the kth nutrient raw material added;

[0089] is the opportunity cost of using the kth nutrient raw material, The market supply and demand situation of the nutritional ingredient k can be obtained through market research or supply and demand forecasting models;

[0090] α: It is the conversion coefficient of feed functional added value, reflecting the impact of quality and efficacy on cost, and can be determined based on product positioning and market feedback;

[0091] H q1 (x): is the q1th characteristic functional index of feed formula x, such as increased milk production, improved milk quality, etc., which can be evaluated through biological experiments;

[0092] S q1 : is the economic value coefficient of the characteristic function q1, which can be estimated by willingness-to-pay survey or market price comparison method;

[0093] r: the total number of characteristic functions of feed formula x;

[0094] The basic part of the feed cost objective function is That is, the actual amount of each raw material added W k Multiply by the unit price c k , plus the opportunity cost of raw materials M k The sum of the opportunity costs It reflects the potential cost of using the raw material when the market changes. Specifically, when the supply of raw material k is insufficient to meet the demand ( When the supply exceeds the demand ( When the opportunity cost is low, the opportunity cost is low. Incorporating it into cost accounting can more comprehensively and dynamically evaluate the economic feasibility of raw material selection, guide formulators to weigh market supply and demand conditions, and use resources rationally.

[0095] Denominator of the feed cost objective function This reflects the premium effect of feed quality and efficacy. When the feed has outstanding performance in improving immunity and intestinal health, that is, H q1 When (x) is high, consumers may be willing to pay a higher price, thereby increasing the added value of the product. q1(x) Some indicators that reflect the special benefits brought by the animal feed are the added value compared with ordinary feed, for example, microbial activity: the survival rate and reproduction capacity of microorganisms in the feed. The higher the microbial activity, the more obvious the probiotic effect of the feed; nutritional absorption rate: the proportion of various nutrients (such as protein, vitamins, minerals, etc.) in the feed absorbed and utilized by animals. The higher the absorption rate, the higher the feed utilization efficiency; milk production increase: the increase in the average daily milk production of animals after using the feed; milk quality improvement: the degree of improvement in the content of nutrients such as protein and milk fat in milk after using the feed; the higher the values ​​of these special functional indicators, the greater the added benefits of the feed. Parameter S q1 The economic value coefficient of the q1th special function can be estimated through market research methods; for example, for every 1% increase in microbial activity, the added value of feed increases by 50 yuan / ton; for every 1% increase in nutrient absorption rate, the added value of feed increases by 30 yuan / ton; for every 1kg increase in daily average milk production, it is equivalent to an increase of 100 yuan / ton in added value of feed; for every 0.1% increase in milk fat rate, it is equivalent to an increase of 80 yuan / ton in added value of feed. These coefficients quantify the special functions into economic value. The larger the coefficient, the greater the contribution of the special function to the overall economic benefits. The ratio of the quality premium item to the basic cost item can be regarded as the added value created by the unit cost. When the feed formula x is innovative in improving product efficacy and meeting special needs, the value of the denominator will increase, thereby reducing the unit cost and improving the economic benefits of production.

[0096] The feed cost objective function mainly represents the trade-off between production cost and product added value of feed formula x. Specifically, the numerator represents the basic production cost of feed formula x, where c k is the unit price of raw material k, W k (x) is the amount added, Its opportunity cost (and market supply and demand This part comprehensively considers the actual amount of raw materials used and the potential cost of use, and fully reflects the economic constraints of the formula design. Introduced the special function performance of feed formula x q1 (x) and its economic value S q1,α is the conversion coefficient of the functional added value of feed, which reflects the quality premium ability. When the formula is innovative in terms of increasing milk production and improving milk quality, the denominator will increase, reducing unit cost and increasing added value. This part reflects the differentiated competition strategy of feed formula, emphasizing the contribution of product quality and efficacy to profitability. The ratio of the numerator to the denominator can be regarded as the economic value created by the unit production cost. The cost objective function is guided by the minimization of this ratio, and promotes formula design to focus on developing new functions and new selling points while controlling raw material costs to achieve "good quality and low price". In general, the feed cost objective function quantitatively describes the cost-effectiveness characteristics of feed formula from an economic perspective, comprehensively weighs multiple factors such as production input, market conditions, and product innovation, and provides an optimization direction for achieving cost control and benefit improvement of feed formula.

[0097] These three objective functions describe the key performance of feed formula from different dimensions such as microbial fermentation, animal nutrition, and production economy, reflecting the multi-objective optimization problems faced by feed formula design. The reasonable construction of objective functions is the basis for feed formula optimization. By introducing innovative influencing factors and function structures, it helps to improve the applicability and practicality of the optimization model, and provides new ideas for solving industry pain points and promoting feed technology progress.

[0098] In an embodiment of the present application, the constraints include ratio constraints, nutrient raw material dosage constraints, microbial viable bacteria count constraints, nutrient absorption rate constraints and cost constraints; the ratio constraint is that the sum of the mass fractions of all nutrient raw materials in the nutrient raw material formula is 1; the nutrient raw material dosage constraint is that the amount of the k-th nutrient raw material added is greater than or equal to the minimum amount of the k-th nutrient raw material added, and less than or equal to the maximum amount of the k-th nutrient raw material added, k = 1, 2, ..., p, p is the total number of nutrient raw materials; the microbial viable bacteria count constraint is that the viable bacteria count of the i-th microorganism is greater than or equal to the minimum viable bacteria count requirement of the i-th microorganism, i = 1, 2, ..., m, m is the total number of microbial species; the cost constraint is that the feed cost is less than or equal to the upper limit of the feed cost; the nutrient absorption rate constraint is that the absorption rate of the j-th key nutrient is greater than or equal to the difference between the minimum absorption rate requirement of the j-th key nutrient and the temperature deviation term, the pH deviation term and the microbial regulation term.

[0099] Create constraints:

[0100] (1) Ratio constraints

[0101]

[0102] where τ kis the mass fraction of the kth nutrient raw material in all nutrient raw materials, and p is the total number of nutrient raw materials; different nutrient raw materials contain different nutrients, and only reasonable matching can make the feed balanced in terms of energy, protein, minerals, vitamins, etc., without waste, and without affecting the health of animals due to the lack of certain key nutrients; therefore, by reasonably regulating the nutrient ratio through ratio constraints, the nutritional needs of animals can be met to the maximum extent. By controlling the ratio of each nutrient raw material, the nutritional balance of the feed can be ensured to avoid excess or deficiency of certain nutrients.

[0103] (2) Constraints on the amount of nutrient raw materials

[0104]

[0105] in is the minimum addition amount of the kth nutrient raw material, is the maximum addition amount of the kth nutrient raw material, and p is the total number of nutrient raw materials. Each nutrient raw material has its appropriate addition amount range. Too much or too little will affect the quality of the feed. For example, soybean meal has a high protein content, but adding too much will lead to excess protein in the feed, which is not only wasteful, but also increases the burden on the animal's liver and kidneys; while adding too little will not reach the ideal protein level. Therefore, by constraining the amount of nutrient raw materials and controlling each raw material within the optimal range, it is possible to improve nutrient utilization while avoiding unnecessary waste. By limiting the addition amount range of each nutrient raw material, it is possible to avoid excessive or low amounts of certain raw materials, resulting in nutritional imbalance or waste of resources, and maximize the nutritional value of each raw material.

[0106] (3) Constraints on the number of viable microorganisms

[0107]

[0108] in is the minimum viable count requirement for the i-th microorganism, which is usually determined according to the fermentation requirements. For example, the number of lactic acid bacteria should not be less than 1.0×10 8 cfu / g. Probiotics need to reach a certain colonization amount to work. If the number of live bacteria is too low, it is difficult to form a dominant flora in the intestine, and it is difficult to play the role of promoting growth and improving immunity. Therefore, by limiting the number of live microorganisms, ensuring that the amount of each probiotic added is at an effective level, it can better play its probiotic role. By controlling the number of live bacteria of each probiotic, it can ensure that the feed can play a stable probiotic function such as promoting growth and regulating intestinal flora.

[0109] (4) Nutrient absorption rate constraints

[0110]

[0111] in

[0112] Aj (x): actual absorption rate of the jth key nutrient;

[0113] The minimum absorption rate requirement for the jth key nutrient is determined based on the physiological needs of the animal;

[0114] λ j : is the influence coefficient of temperature T on the absorption rate of the jth key nutrient, which needs to be obtained through animal experiment fitting;

[0115] μ j : is the influence coefficient of pH value on the absorption rate of the jth key nutrient, which needs to be obtained through animal experiment fitting;

[0116] ν j : is the number of viable bacteria V of the i-th microorganism i (x) The coefficient of influence on the absorption rate of the jth key nutrient must be obtained through animal experiment fitting;

[0117] T opt : The temperature that is most suitable for nutrient absorption in the animal intestine;

[0118] pH opt : The pH value that is most suitable for nutrient absorption in the animal intestine;

[0119] T max : is the highest temperature of the animal's intestine;

[0120] T: actual temperature of the animal's intestine;

[0121] T min : The lowest temperature of the animal's intestines;

[0122] pH min : The lowest pH value in the animal intestine;

[0123] pH max : The highest pH value in the animal intestine;

[0124] κ ji : is the interaction coefficient between the i-th microorganism and the j-th key nutrient, reflecting the promotion or inhibition of the microorganism on the absorption and metabolism of nutrients, and needs to be determined through in vitro fermentation experiments;

[0125] is the temperature deviation term;

[0126] is the pH deviation term;

[0127] It is a microbial regulation item;

[0128] Even if the nutrient content in the feed is sufficient, if the animal's digestion and absorption capacity is low, it is difficult to meet the nutritional needs of growth and lactation. Therefore, in addition to controlling the amount of nutrients added, it is also necessary to constrain the absorption rate to ensure that key nutrients can be effectively utilized; by setting nutrient absorption rate constraints, the scientific nature of the feed formula can be further improved to better meet the nutritional needs of animals. max 、T min , pH max , pH min According to the physiological conditions of animals, the nutrient absorption rate constraint takes into account the impact of microenvironmental conditions such as intestinal temperature and pH on nutrient absorption, and is quantified using the squared exponential function of the deviation. When the conditions deviate from the most suitable state, the absorption rate drops sharply. j , μ j It reflects the sensitivity of environmental factors to the absorption rate of different nutrients. The nutrient absorption rate constraint also takes into account the regulatory effect of the synergistic and antagonistic effects of microbial populations on nutrient absorption. It is superimposed in the form of linear weighting. When the number of beneficial bacteria increases or the number of harmful bacteria decreases, the nutrient absorption rate increases. ji This formula reflects the intensity and direction of the interaction between different microorganisms and nutrients. This formula combines multiple influencing factors and proposes a relatively comprehensive and quantitative nutrient absorption rate constraint condition, which can be used to guide the optimization of microecological preparations and feed formulations. When environmental conditions deteriorate or the flora is imbalanced, the minimum absorption rate requirement must be increased accordingly. In general, when the temperature and pH are close to the optimal value and the number of beneficial bacteria increases, the absorption rate of nutrients increases; otherwise, it decreases. The formula can be used to quantitatively evaluate and predict the effect of microecological regulation on nutrient absorption.

[0129] (5) Cost constraints

[0130]

[0131] Among them C max The upper limit of feed cost is usually determined based on market price and economic benefits, such as no more than 2,000 yuan per ton. Farms pursue profit maximization, so economic feasibility needs to be considered when formulating feed. Although adding certain expensive nutritional enhancers can greatly improve the nutritional level, it will also significantly increase costs and reduce the economic benefits of farming; by controlling feed costs within a certain range through cost constraints, it is possible to achieve an economically efficient balance while ensuring feed nutrition and quality; by limiting the upper limit of feed costs, it is possible to meet the nutritional needs of animals while taking into account the economic benefits of the farm, avoiding unnecessary cost expenditures due to the use of overly expensive raw materials.

[0132] The above objective functions and constraints together constitute a feed formula optimization model, which comprehensively considers microbial factors, nutritional factors and economic factors, and constrains and optimizes the feed formula from different angles, in order to achieve multiple beneficial effects: by optimizing microbial activity and viable count, the growth-promoting and intestinal flora-regulating effects of probiotics in feed can be fully utilized to improve the health of animals; by optimizing nutrient absorption rate and nutrient ratio, the nutrient utilization efficiency of feed can be improved, the nutritional needs of animal growth and lactation can be met, and production performance can be improved; by optimizing feed cost, the breeding cost can be reduced while ensuring feed quality, and the economic benefits of breeding can be improved. The realization of these beneficial effects is the result of systematic optimization of feed formula by weighing multiple objective functions through mathematical modeling and optimization solution, finding the optimal balance point under the constraints. This method of optimizing feed formula by constructing a mathematical model can overcome the limitations of traditional empirical formulas, solve the optimal solution in a larger decision space, thereby comprehensively improving the nutritional value, probiotic effect and economic performance of feed, and better meeting the diversified needs of animal breeding and production.

[0133] S103. Solve the feed formula optimization model using an intelligent optimization algorithm to obtain an optimal microbial formula and an optimal nutritional raw material formula from a set of candidate microbial formulas and a set of candidate nutritional raw material formulas.

[0134] In some embodiments, the intelligent optimization algorithm is one of a genetic algorithm (GA), a particle swarm optimization algorithm (PSO), and an artificial bee colony algorithm (ABC).

[0135] For example, taking PSO as an example, each candidate recipe can be regarded as a "particle" in the search space, and the position of the particle corresponds to a recipe. By iteratively updating the position and speed of the particle, the population continues to move closer to the optimal recipe.

[0136] Particle coding: Arrange the feed formula in a certain order to form an n 1 dimensional particle, that is, y=(y 1 ,y 2 ,...,y n1 ), n 1 =N, N is the total number of decision variables;

[0137] The particle position update formula is:

[0138] y i' (t+1)=y i' (t)+v i' (t+1);

[0139] The particle velocity update formula is:

[0140]

[0141] In the formula, y i' 、v i' Represent the position and velocity of particle i', 1≤i'≤n 1 ;p i' is the best position found so far by particle i', p g is the global best position found by the entire population so far; ω is the inertia weight, c 1 is the first learning factor, c 2 is the second learning factor, is a random number one, is the random number 2, y i' (t) represents the position of the i'th particle at the tth iteration, v i' (t) represents the velocity of the i'th particle at the tth iteration, v i' (t+1) represents the velocity of the i'th particle at the t+1th iteration, y i' (t+1) represents the position of the i'th particle at the t+1th iteration.

[0142] When the number of iterations reaches the preset maximum value, or the improvement of the objective function value after several consecutive iterations is less than a given threshold, the algorithm terminates and outputs the current global optimal solution as the optimal feed formula.

[0143] Intelligent optimization algorithm is a kind of heuristic search algorithm that simulates the intelligent behavior of nature. It approaches the global optimal solution through iterative optimization and is suitable for solving complex combinatorial optimization and nonlinear programming problems. The algorithm starts with a group of random particles and finds the optimal solution through iteration. In each iteration, the particles update themselves by tracking individual extreme values ​​and global extreme values, and continue to move closer to the optimal area. The inertia weight ω reflects the tendency of the particle to maintain the original speed, and the learning factor c 1 、c 2 Respectively represent the weights of particles learning from individual extreme values ​​and global extreme values, is a random number between 0 and 1. By setting these parameters reasonably, the PSO algorithm can search for the global optimal solution or suboptimal solution in a short time. Of course, the principles and applicable conditions of different optimization algorithms are different, and the appropriate algorithm needs to be selected according to the specific problem.

[0144] The optimization process of feed formula is mainly reflected in the construction and solution of multi-objective models, with microbial activity, nutrient absorption rate and feed cost as optimization targets and feed as decision variables. Under relevant constraints, intelligent optimization algorithms (such as genetic algorithms, particle swarm algorithms, etc.) are used to search for the optimal solution to obtain the optimal microbial formula and the optimal nutritional raw material formula.

[0145] The microorganisms in the optimal microbial formula include at least three types: lactic acid bacteria, yeast, and Bacillus.

[0146] The optimal nutritional raw material formula includes at least corn, soybean meal, bran, fish meal, yeast powder, vitamin premix, and mineral premix.

[0147] The vitamin premix includes at least VA, VD, and VE; the mineral premix includes at least Ca, P, Fe, Cu, Zn, and Mn.

[0148] The total amount of microorganisms in the optimal microbial formula is 5.0×10 9 -1.0×10 11 cfu / g, among which, by mass percentage, lactic acid bacteria accounted for 40%-60%, yeast accounted for 20%-40%, and Bacillus accounted for 10%-30%, with lactic acid bacteria accounting for the highest proportion.

[0149] The lactic acid bacteria are one or more of Lactobacillus rhamnosus, Lactobacillus casei and the like.

[0150] The yeast is one or more of Candida, KF-7 yeast and the like.

[0151] The Bacillus is one or more of Bacillus licheniformis, Lactobacillus acidophilus and the like.

[0152] The nutritional raw material formula is, by mass percentage, 40%-60% corn, 20%-30% soybean meal, 5%-15% bran, 3%-8% fish meal, 1%-5% yeast powder, 0.1%-0.5% vitamin premix, and 0.5%-1.5% mineral premix.

[0153] The animal feed optimization method of the present application can bring the following beneficial effects:

[0154] This optimization method comprehensively considers three key indicators, namely, microbial activity, nutrient absorption rate and feed cost, establishes a multi-objective optimization model, and systematically optimizes the feed formula. Traditional feed formulas often focus on one aspect of performance and are difficult to take into account. However, this method can control feed costs while ensuring microbial activity and nutrient absorption rate through weighted processing, achieve multi-objective balance, and make the feed formula more reasonable and economical. When establishing the optimization model, not only the target values ​​of various indicators are set, but also the constraints of raw material dosage, microbial viable count, nutrient absorption rate and other aspects are considered, so that the optimization results are more in line with the actual needs of animal production. This optimization method is highly targeted and practical. It is based on the special environment of the animal stomach and designs and optimizes the animal feed formula according to its physiological characteristics. The optimized feed formula can give full play to the probiotic functions of microorganisms in promoting growth and regulating intestinal health, improve the digestion, absorption and utilization rate of various nutrients in the feed, thereby significantly improving the nutritional status of animals and improving milk production performance and milk quality. This optimization method provides a set of scientific and systematic ideas and methods for the development of animal feed. By building and solving a multi-objective optimization model, the optimal formula combination can be quickly screened and determined, reducing a large amount of repetitive work in traditional test optimization methods, shortening product development cycles, and reducing test costs. At the same time, the optimization method is universal and can flexibly adjust the target weights and constraints according to actual needs to meet the requirements of different application scenarios.

[0155] The animal feed of the embodiment of the present application comprises a microbial component, a nutrient raw material component and a multilayer microcapsule;

[0156] In the embodiments of the present application, the microbial component adopts the optimal microbial formula obtained by the optimization method, and the nutrient raw material component adopts the optimal nutrient raw material formula obtained by the optimization method.

[0157] In some embodiments, the total amount of microorganisms in the animal feed is 5.0×10 9 -1.0×10 11 cfu / g, of which lactic acid bacteria account for 40%-60%, yeast accounts for 20%-40%, and Bacillus accounts for 10%-30%.

[0158] As a non-limiting example, the total amount of microorganisms in animal feed includes but is not limited to 5.0×10 9 cfu / g, 1.0×10 10 cfu / g, 2.0×10 10 cfu / g, 4.0×10 10 cfu / g, 5.0×10 10 cfu / g, 5.5×10 10 cfu / g, 6.0×10 10 cfu / g, 6.5×10 10cfu / g, 7.0×10 10 cfu / g, 7.5×10 10 cfu / g, 8.0×10 10 cfu / g, 9.0×10 10 cfu / g or 1.0×10 11 cfu / g, etc.

[0159] As a non-limiting example, the proportion of lactic acid bacteria in the microbial component of animal feed includes but is not limited to 40%, 45%, 50%, 55% or 60%, etc.

[0160] As a non-limiting example, the proportion of yeast in the microbial component of animal feed includes but is not limited to 20%, 25%, 30%, 35% or 40%, etc.

[0161] As a non-limiting example, the proportion of Bacillus in the microbial component of animal feed includes but is not limited to 10%, 15%, 20%, 25% or 30%, etc.

[0162] In the embodiments of the present application, lactic acid bacteria account for the largest proportion of the microbial components in animal feed.

[0163] Microorganisms are the key components of fermented feed. The number of live bacteria and the ratio of strains directly affect the fermentation effect. Lactic acid bacteria can produce lactic acid, lower pH, and inhibit putrefactive bacteria, and are the dominant bacteria in fermentation; yeast can produce a variety of nutrients and promote the growth of other beneficial bacteria; Bacillus can produce antibiotics and prevent diseases; the ratio of the three is mainly lactic acid bacteria, and they have a synergistic effect on each other.

[0164] In some embodiments, the lactic acid bacteria are one or more of Lactobacillus rhamnosus, Lactobacillus casei, etc.

[0165] In some embodiments, the yeast is one or more of Candida, KF-7 yeast, etc.

[0166] In some embodiments, the Bacillus is one or more of Bacillus licheniformis, Lactobacillus acidophilus, and the like.

[0167] Lactobacillus rhamnosus can ferment rhamnose to produce lactic acid and synthesize B vitamins at the same time; Lactobacillus casei has a strong ability to produce lactic acid and can inhibit pathogenic bacteria such as Escherichia coli; Candida albicans can produce xylanase and cellulase, which helps digest straw feed; KF-7 yeast can secrete a variety of amino acids and growth factors to promote the growth of lactic acid bacteria; Bacillus licheniformis can produce antibacterial antibiotics to improve animal resistance to disease; Lactobacillus acidophilus has strong acid resistance and can still metabolize normally under acidic conditions.

[0168] If the lactic acid bacteria addition is less than 40%, it is difficult to maintain sufficient fermentation acidity; if it is more than 60%, the fermentation rate is too fast and the acidity is high; if the yeast addition is less than 20%, the growth factor synthesis is insufficient; if it is more than 40%, the yeast protein content affects the feed quality; if the Bacillus addition is less than 10%, the interspecies interaction effect is weak; if it is more than 30%, the feed cost increases. The above ratio can play a synergistic role while taking into account the nutritional balance and production cost of the feed.

[0169] In some embodiments, the nutritional raw material components are, by mass percentage, 40%-60% corn, 20%-30% soybean meal, 5%-15% bran, 3%-8% fish meal, 1%-5% yeast powder, 0.1%-0.5% vitamin premix, and 0.5%-1.5% mineral premix.

[0170] The composition of nutrient raw materials needs to comprehensively consider factors such as the nutritional needs of animals, the complementarity of raw materials, and the substrate preferences of microorganisms. Corn is rich in starch and is the main energy source for ruminants; soybean meal has a high protein content and is rich in lysine; bran contains a large amount of dietary fiber and promotes rumen development; fish meal has excellent protein quality and contains a variety of mineral elements; yeast powder contains special nutrients such as nucleic acids and polysaccharides; vitamins and minerals are trace elements necessary to maintain physiological functions such as growth, reproduction, and lactation. If the amount of corn added is less than 40%, it is difficult to meet the energy demand. If it is higher than 60%, the starch content is too high and it is easy to cause acidosis. If the amount of soybean meal added is less than 20%, the protein supply is insufficient. If it is higher than 30%, the feed price will rise. If the amount of bran added is less than 5%, the fiber effect is not obvious. If it is higher than 15%, it will affect the absorption of other nutrients. If the amount of fish meal added is less than 3%, the supply of high-quality protein is insufficient. If it is higher than 8%, the fat will easily become rancid and deteriorate. If the amount of yeast powder added is less than 1%, the probiotic effect is not good. If it is higher than 5%, the cost will rise sharply. If the amount of vitamin premix added is less than 0.1%, it is difficult to meet the vitamin demand. If it is higher than 0.5%, excessive intake may cause toxic side effects. If the amount of mineral premix added is less than 0.5%, the mineral supply is insufficient. If it is higher than 1.5%, it is easy to cause antagonism and reduce utilization. The above range fully considers the physiological characteristics and economic efficiency of ruminants while ensuring comprehensive nutrition.

[0171] In some embodiments, Figure 2 As shown, the multilayer microcapsule includes three layers: a load core 10, a buffer layer 20 and a sustained-release shell 30. The materials used for the load core 10 include load core material 1 and load core material 2; the buffer layer 20 is made of a buffer layer material; and the sustained-release shell 30 is made of a sustained-release shell material. The load core is used to load the microbial components in animal feed; the buffer layer plays a buffering role, adjusts the internal pH, and mitigates the effects of gastric juice; the sustained-release shell is a surface barrier that controls the disintegration and release behavior of the microcapsule.

[0172] In some embodiments, the load core material one comprises sodium alginate;

[0173] In some embodiments, the second loaded core material includes at least one of chitosan, gelatin, etc.;

[0174] In some embodiments, the buffer layer material includes at least citric acid and sodium bicarbonate;

[0175] In some embodiments, the sustained-release shell material includes, but is not limited to, at least one of a pH-sensitive polymer, HPMCAS, guar gum, and the like;

[0176] Sodium alginate has good biocompatibility and gelling properties, and can be mixed evenly with microorganisms to prepare microspheres. Chitosan can form a coating on the surface of the microspheres to enhance the physical and chemical stability of the microspheres. The buffer layer material can be slowly dissolved under acidic conditions by using substances such as citric acid and sodium bicarbonate. These materials release sufficient buffer ions during the reaction to form a pH buffer around the loaded core microspheres, so that the internal environment is maintained in the pH range (6.5-7.5) that is most suitable for the growth of microorganisms. This pH buffer layer can effectively reduce the impact of gastric juice and protect microorganisms from being destroyed by the acidic environment. The sustained-release shell material uses hydroxypropyl methylcellulose acetate succinate (HPMCAS), which is a pH-sensitive polymer that will only dissolve when the environmental pH is higher than 7. Therefore, coating HPMCAS in the outermost layer of the microcapsule can achieve the effect of gastrointestinal targeted release, that is, the microcapsule remains intact in the rumen with a lower pH, and begins to disintegrate and release in the ruminant with a higher pH.

[0177] In some embodiments, the average particle size of the multilayer microcapsules is 100-500 μm.

[0178] As a non-limiting example, the average particle size of the microcapsules may be 100 μm, 200 μm, 300 μm, 400 μm, or 500 μm, etc.

[0179] If the particle size of the microcapsule is too small (e.g. <100μm), the specific surface area of ​​the microcapsule is large and the amount of microorganisms embedded is limited; if the particle size is too large (e.g. >500μm), the residence time of the microcapsule in the digestive tract is short and the release is insufficient. The particle size range of 100-500μm can take into account both the microbial load and the in vivo residence time, ensuring a good enteric-coated targeted release effect.

[0180] The animal feed of the present application can at least bring the following beneficial effects:

[0181] The microbial components and nutrient raw material components in animal feed adopt the optimal microbial formula and the optimal nutrient raw material formula that have been fully optimized, fully considering key factors such as microbial activity, nutrient absorption rate and feed cost, so that the overall performance of the feed is significantly improved; by scientifically selecting high-quality strains and nutrient raw materials, and optimizing the proportion of each component through mathematical models, the optimal microbial formula and nutrient raw material formula are finally obtained to ensure the synergistic and complementary effects of various components in the feed. The innovative multi-layer microcapsule encapsulation technology used in feed can effectively protect the survival of microorganisms in the acidic gastric juice environment. The multi-layer microcapsules are composed of a loaded core, a buffer layer and a sustained-release shell from the inside to the outside. The microbial cells are loaded in the core, and the outer pH-sensitive polymer shell is enteric, which can avoid erosion by gastric acid. The buffer layer in the middle further reduces the acidity inside the capsule, providing a stable living environment for microorganisms. Therefore, the probiotics in the feed can safely pass through the acidic gastric juice area of ​​the animal and enter the ruminant stomach to exert their biological functions.

[0182] Multilayer microcapsules can achieve controlled sustained release of microorganisms and nutrients in the animal stomach. The particle size of the microcapsules is optimized between 100-500μm, which matches the residence time of the ruminant contents. In the ruminant, the sustained-release shell gradually dissolves and the buffer layer disintegrates, allowing the microorganisms and nutrients to be slowly released, prolonging the contact time between the feed ingredients and the ruminant microenvironment, thereby improving the digestion and absorption rate of nutrients. At the same time, the continuously released probiotics can colonize and reproduce in the ruminant, promote microecological balance, and improve the intestinal health of ruminants.

[0183] High-quality microbial strains are used in the feed, including lactic acid bacteria, yeast and Bacillus, which have multiple physiological functions such as colonization of the ruminant stomach, secretion of digestive enzymes, and synthesis of vitamins, which can significantly improve feed conversion rate and promote nutrient absorption. At the same time, probiotics can also antagonize pathogens, regulate intestinal flora, and enhance animal immunity. The nutritional raw material formula of the feed is scientific and reasonable. Corn, soybean meal, bran, etc. provide sufficient energy and protein sources, fish meal and yeast powder supplement high-quality protein and bioactive substances, and vitamin and mineral premixes can regulate animal physiological functions and meet the needs of lactating cows for trace elements. The nutritional ratio is comprehensive and balanced to ensure that the animals have sufficient food intake and good nutritional status.

[0184] The animal feed preparation method of the embodiment of the present application is used to prepare the above-mentioned animal feed, such as Figure 3 As shown, the following steps are included:

[0185] S201. Microbial fermentation: The selected lactic acid bacteria, yeast and bacillus were inoculated into MRS medium, YPD medium and NB medium respectively, and fermented at 37°C for 24-48h. The microbial cells were collected by centrifugation and washed.

[0186] Lactic acid bacteria grow in MRS medium, which is a selective medium specifically used for the isolation and cultivation of lactic acid bacteria; yeast grows in YPD medium, which contains yeast powder, glucose and other ingredients to meet the nutritional needs of yeast; Bacillus grows in NB medium, which is rich in nitrogen and carbon sources such as peptone and is suitable for the growth of aerobic bacteria. After the fermentation is completed, the cells are collected by centrifugation, washed several times with physiological saline, and the residual culture medium is removed to obtain pure high-concentration live bacteria.

[0187] S202, microcapsule preparation: the collected lactic acid bacteria, yeast, and bacillus cells are prepared according to the optimal microbial formula, and then the microbial cells are evenly mixed with the solution configured with the load core material one, and the load core microspheres are prepared by injection; then the load core microspheres are placed in a solution configured with the load core material two, and a coating of the load core material two is formed on the surface of the load core microspheres to obtain pre-coated load core microspheres; then, the pre-coated load core microspheres are immersed in a solution configured with the buffer layer material, and a pH buffer layer is formed around the load core microspheres through the chemical reaction of the buffer layer material; finally, the sustained-release shell material is dissolved in an organic solvent, and a layer of uniform and dense enteric shell is coated on the surface of the microspheres by spray drying to obtain multi-layer microcapsules with a multi-layer structure.

[0188] In the process of microcapsule preparation, the injection method can achieve monodispersity and size controllability of droplets, and is a commonly used method for preparing microspheres. Spray drying is a mild microcapsule coating technology that allows the polymer to be evenly coated on the surface of the microspheres after atomization and drying.

[0189] S203, mixing nutrient raw materials and microorganisms: crushing and sieving the nutrient raw materials, and mixing them according to the proportion of the optimal nutrient raw material formula; then adding the multi-layer microcapsules, and continuing to mix evenly to obtain animal feed powder.

[0190] S204, granulation and molding: the animal feed powder is pressed into granules with a tablet press, and the particle size is 2-5 mm.

[0191] The particle size affects the palatability and stability of the feed. Particles that are too small are prone to cause dust, while particles that are too large are difficult for cattle to eat. 2-5mm is the ideal particle size range for animals to eat.

[0192] As a non-limiting example, the particle size of the granules can be 2 mm, 3 mm, 4 mm or 5 mm, etc. Tabletting can increase the compactness and hardness of the feed and reduce losses in storage and transportation.

[0193] The animal feed preparation method of the embodiment of the present application, in addition to having the beneficial effects of the animal feed of the embodiment of the present application, can obtain a microcapsule product with uniform particle size and storage resistance by adopting modern microcapsule preparation processes such as emulsification-coagulation-spray drying. Compared with directly adding probiotics, microcapsule embedding greatly improves the survival rate of microorganisms during feeding and reduces losses; the multi-layer structure design makes the microcapsule have a sustained release characteristic, avoids the sudden release of the core substance, is conducive to maintaining a stable number of probiotics and continuous nutrient supply in the gastrointestinal tract, improves the utilization efficiency of feed, and the advanced preparation process lays the foundation for the industrial application of animal feed. The animal feed preparation method provided in the embodiment of the present application, through the optimized combination of microbial formula and nutrient raw material formula, combined with multi-layer microcapsule embedding technology, can significantly improve feed utilization, improve animal gastrointestinal health, and ultimately improve animal production performance; the preparation method has advanced technology, scientific principles, and significant effects, and has broad application prospects in the field of animal breeding.

[0194] In summary, the present invention has formed a set of complete technologies for selecting and breeding microbial strains, optimizing nutritional formulas, and constructing microcapsule delivery systems, which provide theoretical guidance and key technical support for the development of new animal feeds; by comprehensively considering multiple goals such as feed safety, nutritional value, and production costs, and utilizing modern biotechnology and engineering methods, precise nutritional regulation and functional enhancement of ruminant livestock feeds can be achieved, providing strong guarantees for improving animal breeding efficiency and dairy product quality; this technical idea has certain universality and demonstration significance, and is also of reference value for the research and development of other livestock feeds.

[0195] Certain features of the present technology are further illustrated in the following non-limiting examples.

[0196] Example 1

[0197] According to the optimized formula of the present invention, animal feed is prepared, the microbial formula is: by mass percentage, Lactobacillus rhamnosus accounts for 50%, Candida accounts for 30%, and Bacillus licheniformis accounts for 20%, and the nutrient raw material formula is: by mass percentage, corn 50%, soybean meal 24%, bran 18%, fish meal 5.7%, yeast powder 1%, vitamin premix 0.3%, and mineral premix 1%. Sodium alginate is used as the first load core material, chitosan is used as the second load core material, citric acid and sodium bicarbonate are used as buffer layer materials, and HPMCAS is used as a sustained-release shell material to prepare a three-layer microcapsule with an average particle size of 500 μm.

[0198] Example 2

[0199] According to the optimized formula of the present invention, animal feed is prepared. The microbial formula is as follows: by mass percentage, Lactobacillus casei accounts for 55%, KF-7 yeast accounts for 20%, and Lactobacillus acidophilus accounts for 25%. The nutrient raw material formula is as follows: by mass percentage, corn 58%, soybean meal 30%, bran 5%, fish meal 4%, yeast powder 2%, vitamin premix 0.5%, mineral premix 0.5%, sodium alginate is used as the first load core material, chitosan is used as the second load core material, citric acid and sodium bicarbonate are used as buffer layer materials, and guar gum is used as a sustained-release shell material to prepare three-layer microcapsules, wherein the average particle size is 250 μm.

[0200] Example 3

[0201] According to the optimized formula of the present invention, animal feed is prepared. The microbial formula is as follows: by mass percentage, Lactobacillus rhamnosus accounts for 40%, Lactobacillus casei accounts for 10%, Candida accounts for 40%, and Bacillus licheniformis accounts for 10%. The nutrient raw material formula is as follows: by mass percentage, corn accounts for 60%, soybean meal accounts for 22.4%, bran accounts for 12%, fish meal accounts for 3%, yeast powder accounts for 1%, vitamin premix accounts for 0.1%, and mineral premix accounts for 1.5%. Sodium alginate is used as a first load core material, gelatin is used as a second load core material, citric acid and sodium bicarbonate are used as buffer layer materials, and HPMCAS is used as a sustained-release shell material to prepare three-layer microcapsules, and the average particle size of the three-layer microcapsules is 100 μm.

[0202] Example 4

[0203] Animal feed is prepared according to the optimized formula of the present invention. The microbial formula is: by mass percentage, Lactobacillus casei accounts for 40%, KF-7 yeast accounts for 15%, Lactobacillus acidophilus accounts for 15%, and Bacillus licheniformis accounts for 30%. The nutritional raw material formula is: by mass percentage, corn 40%, soybean meal 30%, bran 15%, fish meal 8%, yeast powder 5%, vitamin premix 0.5%, and mineral premix 1.5%. Sodium alginate is used as the first load core material, chitosan is used as the second load core material, citric acid and sodium bicarbonate are used as buffer layer materials, and guar gum is used as a sustained-release shell material to prepare a three-layer microcapsule with an average particle size of 230 μm.

[0204] Example 5

[0205] According to the optimized formula of the present invention, animal feed is prepared. The microbial formula is: by mass percentage, Lactobacillus rhamnosus accounts for 60%, Candida accounts for 15%, KF-7 yeast accounts for 15%, Lactobacillus acidophilus accounts for 10%, the nutrient raw material formula is: by mass percentage, corn 45%, soybean meal 30%, bran 15%, fish meal 4.2%, yeast powder 5%, vitamin premix 0.2%, mineral premix 0.6%, sodium alginate is used as the first load core material, chitosan is used as the second load core material, citric acid and sodium bicarbonate are used as buffer layer materials, HPMCAS is used as a sustained-release shell material, and three-layer microcapsules are prepared, and the average particle size is 180 μm.

[0206] Comparative Example 1

[0207] A feed without added microorganisms was prepared, and its nutritional raw material formula was the same as that in Example 1.

[0208] Comparative Example 2

[0209] Animal feed containing a single lactic acid bacterium (Lactobacillus rhamnosus) was prepared. The amount of lactic acid bacteria added was the same as that in Example 1, the nutritional raw material formula was consistent, a microcapsule single-layer structure was adopted, and the loaded core microspheres containing lactic acid bacteria were wrapped with chitosan.

[0210] Comparative Example 3

[0211] Animal feed containing a single yeast (Candida) was prepared, the yeast addition amount was the same as in Example 1, the nutrient raw material formula was consistent, a microcapsule single-layer structure was adopted, and the loaded core microspheres containing the yeast were wrapped with chitosan.

[0212] Comparative Example 4

[0213] Animal feed containing a single bacillus (Bacillus licheniformis) was prepared. The amount of bacillus added was the same as that in Example 1, the formula of nutrient raw materials was consistent, a microcapsule single-layer structure was adopted, and the loaded core microspheres containing bacillus were wrapped with chitosan.

[0214] Comparative Example 5

[0215] According to the microbial formulation of Example 1, a bulk microbial preparation without microcapsule embedding was prepared and mixed with the nutrient raw material formulation of Example 1.

[0216] Comparative Example 6

[0217] The microbial formula of Example 1 was used, but the microbial formula was adjusted to 70% of Lactobacillus rhamnosus, 20% of Candida, and 10% of Bacillus licheniformis. The nutrient raw material formula was consistent, and three-layer microcapsules were prepared, and the average particle size was 180 μm.

[0218] Comparative Example 7

[0219] The microbial formula and ratio of Example 1 were used, but the nutrient raw material formula was adjusted to: by mass percentage, 70% corn, 21% soybean meal, 5% bran, 2.6% fish meal, 1% yeast powder, 0.1% vitamin premix, and 0.3% mineral premix to prepare three-layer microcapsules with an average particle size of 180 μm.

[0220] Test method:

[0221] 1. Take equal amounts of samples from Examples 1-5 and Comparative Examples 1-7, respectively, place them in an artificially simulated environment (temperature 39° C., pH 6.2), incubate them for 48 hours, and determine the survival rate of the microorganisms.

[0222] 2. Take the incubated samples and add them to the in vitro artificial rumen fermentation system. Control the pH value, temperature and other conditions. Take samples every 2 hours to measure the digestibility of each major nutrient (protein, fat, fiber, minerals, etc.).

[0223] 3. 20 high-yield dairy cows with similar weight, age and milk production were selected and randomly divided into 10 groups, with 2 cows in each group. The cows were fed with the feeds prepared in Examples 1-5 and Comparative Examples 1-7 for 30 consecutive days. The feed intake was recorded every day, and the milk yield, milk fat rate and milk protein rate were measured every week.

[0224] 4. Statistically analyze the data of each group, compare the milk fat rate, milk protein rate and microbial activity of milk produced by dairy cows fed with different formula feeds, and evaluate the feeding effect.

[0225] Test results:

[0226] Table 1 Microbial survival rate of feeds with different formulas

[0227] Grouping Survival rate (%) Example 1 85.2 Example 2 82.4 Example 3 87.6 Example 4 80.8 Example 5 90.5 Comparative Example 1 -- Comparative Example 2 53.6 Comparative Example 3 46.7 Comparative Example 4 38.2 Comparative Example 5 62.5 Comparative Example 6 74.1 Comparative Example 7 68.8

[0228] As can be seen from Table 1, the survival rates of the microorganisms in Examples 1-5 are all above 80%, among which the survival rate of Example 5 is as high as 90.5%, while the survival rates of Comparative Examples 2-7 are generally lower, and the highest survival rate of Comparative Example 6 is only 74.1%. This shows that the multi-layer microcapsule encapsulation technology adopted by the present invention can effectively protect the survival of microorganisms in feed in an acidic environment, allowing them to safely pass through the rumen and play a role in the ruminant. In contrast, a large part of microorganisms that are not encapsulated and protected (such as Comparative Example 5) or microorganisms that are only encapsulated with a single layer of material (such as Comparative Examples 2-4) will die in the low pH environment of the rumen, thereby affecting the fermentation effect. It can be seen that the microcapsule structure of the present invention is reasonably designed and has a significant effect in improving the survival rate of microorganisms.

[0229] Table 2 In vitro digestibility of main nutrients in different feed formulas

[0230]

[0231]

[0232] Table 2 compares the in vitro digestibility of the main nutrients in different feed formulas. It can be seen that the digestibility of protein, fat, fiber, calcium and phosphorus in Examples 1-5 is significantly higher than that in Comparative Examples 1-7. Taking protein as an example, the digestibility of the embodiments is between 74.9% and 83.5%, with an average value of 78.9%; while the digestibility of the comparative example is between 58.2% and 73.8%, with an average value of only 67.0%. This shows that the present invention greatly improves the digestibility and absorption rate of feed ingredients by optimizing the microbial formula and the nutrient raw material formula, and using multi-layer microcapsules to achieve the synergistic sustained release of nutrients and microorganisms. In contrast, the feed without added microorganisms (such as Comparative Example 1), or the feed with only some parameters optimized (such as Comparative Examples 2-4 and 6-7), has a relatively low nutrient utilization efficiency. It can be seen that the present invention can significantly improve the digestion characteristics of feed and provide more adequate nutrition for dairy cows.

[0233] Table 3 Feed intake of dairy cows after feeding different formula feeds

[0234]

[0235]

[0236] Table 3 shows the average daily feed intake of dairy cows after feeding different formula feeds. As can be seen from the table, the feed intake of dairy cows fed with the feeds obtained in Examples 1-5 of the present invention is all above 18.5kg, with the highest reaching 19.4kg (Example 5); while the feed intake of dairy cows fed with the feeds of Comparative Examples 1-7 is generally less than 18.2kg. This shows that the feed of the present invention not only has high nutritional value, but also has good palatability, can effectively stimulate dairy cows to eat, and increase feed intake. This may be because the aromatic substances produced during the fermentation process, as well as the added probiotics such as yeast and lactic acid bacteria, improve the flavor characteristics of the feed and induce dairy cows to eat more. In contrast, the comparative example has problems such as malnutrition, poor fermentation or poor taste, resulting in a low feed intake. It can be seen that the feed of the present invention helps to promote dairy cows to eat, laying a foundation for the subsequent improvement of milk production performance.

[0237] Table 4 Milk production of dairy cows after feeding different formula feeds

[0238]

[0239]

[0240] Table 4 records in detail the changes in milk production of dairy cows during the feeding test. It can be seen that the milk production of dairy cows in each group was basically the same at the beginning of the test, averaging about 27-28 kg; but as the test progressed, the milk production of dairy cows fed with the feed of the present invention (Examples 1-5) increased week by week, and the increase was large, and by the fourth week, all exceeded 32 kg; among them, the milk production of the Example 5 group increased from the initial 26.9 kg to 35.8 kg, an increase of up to 33%; while the milk production of dairy cows fed with the comparative feed increased slowly, and some even decreased (such as Comparative Example 1); by the fourth week, the milk production of Comparative Examples 1-7 was 26.3, 31.2, 29.6, 29.0, 32.5, 31.5 and 31.9 kg, respectively, which was generally lower than the Example group.

[0241] The significant difference in milk production is mainly due to the difference in feed nutritional value and microbial action. On the one hand, the feed of the present invention is scientifically proportioned, and while providing sufficient energy and protein to dairy cows, it also supplements various mineral elements and vitamins required for raw milk, promotes the development of mammary glands and the synthesis and secretion of milk. On the other hand, the probiotics in the feed of the present invention multiply in large quantities in dairy cows, produce a variety of enzymolysis substances, antibacterial substances and growth factors, improve intestinal microecology, improve nutrient absorption and immune function, thereby indirectly promoting lactation. In contrast, the nutritional level and prebiotic effect of the control feed are obviously insufficient, and it is difficult to support high production.

[0242] In addition, the microorganisms and metabolites in the feed of the present invention can also be secreted into the milk through the systemic circulation, increasing the number of beneficial bacteria in the milk, which not only indicates the improvement of the quality of dairy products, but also means that the feed of the present invention can be used as a probiotic preparation, play a role through the transmission of the food chain, and ultimately benefit human health. It can be judged from Tables 3 and 4 that the formula of the present invention can significantly increase the feed intake and milk production of dairy cows, and the production performance is better than that of conventional feed, and has extremely high application value and market prospects.

[0243] Table 5 Quality indexes of milk from dairy cows fed with different formula feeds

[0244]

[0245]

[0246] Table 5 examines the quality indicators of cow milk after feeding different formula feeds. It can be seen from the fat rate and protein rate that the example groups are significantly higher than the control group. The fat rate reflects the fat content in milk. Examples 1-5 are between 4.01% and 4.32%, with an average of 4.16%, while Comparative Examples 1-7 are only 3.64%-3.95%, with an average of 3.82%. The protein rate reflects the protein content in milk. Examples 1-5 are between 3.30% and 3.58%, with an average of 3.44%, while Comparative Examples 1-7 are only 3.06%-3.26%, with an average of 3.18%. It can be seen that the feed of the present invention is conducive to improving the synthesis of milk fat and milk protein and improving the quality of milk components. This is mainly due to the balanced nutrient composition in the feed, especially the high fat and protein content, and is fermented by probiotics into a form that is easier to absorb and utilize, providing sufficient substrate for the synthesis of milk fat and milk protein.

[0247] What is more noteworthy is that the microbial activity in the milk of the cows fed with the feed of the present invention is significantly higher than that of the control group. 5 -3.1×10 5 cfu / mL, with an average of 2.5×10 5 cfu / mL, while the comparative examples 1-7 were only 0.8×10 5 -1.7×10 5 cfu / mL, average 1.3×10 5 cfu / mL, which is only about half of the example group. This shows that the probiotics in the feed of the present invention can enter the breast milk through mammary gland secretion, so that the fresh milk maintains a high microbial activity. It is well known that the probiotics in milk are of great significance to human health. They can regulate intestinal flora, enhance the body's immunity, and prevent a variety of diseases. Therefore, the present invention is not only effective in improving milk quantity and quality, but also gives dairy products a higher added value, making it a natural probiotic carrier with both nutrition and health care functions. This is of great significance for meeting the growing health needs of consumers and enhancing the competitiveness of the dairy industry.

[0248] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for optimizing animal feed, characterized in that: The method comprises: Determine candidate microbial formulas and nutrient raw material formulas, and establish candidate microbial formula sets and candidate nutrient raw material formula sets; A feed formula optimization model was established using feed formula including microbial formula and nutrient raw material formula as decision variables; Solve the feed formula optimization model and obtain the optimal microbial formula and the optimal nutritional raw material formula from the candidate microbial formula set and the candidate nutritional raw material formula set.

2. The method for optimizing animal feed according to claim 1, characterized in that: The feed formula optimization model consists of three parts: objective function, constraint conditions, and decision variables; The objective functions include a microbial activity objective function, a nutrient absorption rate objective function and a feed cost objective function; The constraints include ratio constraints, nutrient raw material usage constraints, microbial viable count constraints, nutrient absorption rate constraints and cost constraints.

3. The method for optimizing animal feed according to claim 2, characterized in that: The microbial activity objective function calculates the microbial activity index based on the number of viable microorganisms, the content of key nutrients and the utilization rate of key nutrients by microorganisms, and finds the maximum value of the microbial activity index; The nutrient absorption rate objective function seeks the maximum value based on the weighted nutrient absorption rate; The feed cost objective function is based on feed cost, feed characteristic function index and economic value coefficient of feed characteristic function, and calculates feed cost index through ratio function to find the minimum value of feed cost index.

4. The method for optimizing animal feed according to claim 2, characterized in that: The ratio constraint is that the sum of the mass fractions of all the nutrient raw materials in the nutrient raw material formula is 1; The nutrient raw material usage constraint is that the amount of the kth nutrient raw material added is greater than or equal to the minimum amount of the kth nutrient raw material added, and less than or equal to the maximum amount of the kth nutrient raw material added, k=1, 2, ..., p, p is the total number of nutrient raw materials; The microbial viable count constraint is that the viable count of the i-th microorganism is greater than or equal to the minimum viable count requirement of the i-th microorganism, i=1, 2, ..., m, m is the total number of microbial species; The cost constraint is that the feed cost is less than or equal to the feed cost upper limit; The nutrient absorption rate constraint is that the absorption rate of the j-th key nutrient is greater than or equal to the difference between the minimum absorption rate requirement of the j-th key nutrient and the temperature deviation term, the pH deviation term and the microbial regulation term.

5. The method for optimizing animal feed according to claim 1, characterized in that: The microorganisms in the optimal microbial formula include at least three types: lactic acid bacteria, yeast, and bacillus; The optimal nutritional raw material formula at least includes corn, soybean meal, bran, fish meal, yeast powder, vitamin premix and mineral premix.

6. The method for optimizing animal feed according to claim 5, characterized in that: The optimal microbial formula is: by mass percentage, lactic acid bacteria account for 40%-60%, yeast accounts for 20%-40%, and bacillus accounts for 10%-30%, with lactic acid bacteria accounting for the highest proportion; the lactic acid bacteria are one or more of Lactobacillus rhamnosus and Lactobacillus casei; the yeast is one or more of Candida and KF-7 yeast; the bacillus is one or more of Bacillus licheniformis and Lactobacillus acidophilus; The nutritional raw material formula is as follows: by mass percentage, corn 40%-60%, soybean meal 20%-30%, bran 5%-15%, fish meal 3%-8%, yeast powder 1%-5%, vitamin premix 0.1%-0.5%, and mineral premix 0.5%-1.5%.

7. The method for optimizing animal feed according to claim 5, characterized in that: The optimal microbial formula is: by mass percentage, Lactobacillus rhamnosus accounts for 60%, Candida accounts for 15%, KF-7 yeast accounts for 15%, and Lactobacillus acidophilus accounts for 10%; the nutritional raw material formula is: by mass percentage, corn 45%, soybean meal 30%, bran 15%, fish meal 4.2%, yeast powder 5%, vitamin premix 0.2%, and mineral premix 0.6%.

8. An animal feed, characterized in that: It comprises a microbial component, a nutrient raw material component and a multilayer microcapsule; the microbial component adopts the optimal microbial formula obtained by the animal feed optimization method described in claim 6 or 7, and the nutrient raw material component adopts the optimal nutrient raw material formula obtained by the animal feed optimization method described in claim 6 or 7.

9. The animal feed according to claim 8, characterized in that The multilayer microcapsule comprises three layers, namely, a load core (10), a buffer layer (20) and a sustained-release shell (30); the material used for the load core (10) comprises a load core material 1 and a load core material 2; the buffer layer (20) is made of a buffer layer material; and the sustained-release shell (30) is made of a sustained-release shell material; The loaded core (10) is used to load the microbial components in animal feed; The first load core material includes sodium alginate; the second load core material includes at least one of chitosan and gelatin; the buffer layer material includes at least citric acid and sodium bicarbonate; the sustained-release shell material includes at least one of pH-sensitive polymer, HPMCAS, and guar gum; The average particle size of the multilayer microcapsules is 100-500 μm.

10. A method for preparing animal feed according to any one of claims 8 to 9, characterized in that: include: Microbial fermentation: lactic acid bacteria, yeast, and bacillus were inoculated into MRS medium, YPD medium, and NB medium, respectively, and fermented at 37°C for 24-48 hours. The microbial cells were collected by centrifugation and washed; Preparation of microcapsules: preparing microbial cells according to the optimal microbial formula, and then evenly mixing the microbial cells with the solution configured by the load core material one to prepare the load core microspheres; then placing the load core microspheres in the solution configured by the load core material two, forming a coating of the load core material two on the surface of the load core microspheres, and obtaining pre-coated load core microspheres; then, soaking the pre-coated load core microspheres in the solution configured by the buffer layer material, and forming a pH buffer layer around the load core microspheres; finally, dissolving the sustained-release shell material in an organic solvent, and coating the surface of the microspheres with a uniform and dense enteric shell, and obtaining multi-layer microcapsules with a multi-layer structure; Mixing nutrient raw materials with microorganisms: crushing and sieving the nutrient raw materials, and mixing them according to the ratio of the optimal nutrient raw material formula; then adding multi-layer microcapsules, and continuing to mix evenly to obtain animal feed powder; Granulation: Press the animal feed powder into granules with a particle size of 2-5mm.

Images