阅读说明：本技术 一种粘土/氨基酸复合物添加剂及其制备方法和应用 (Clay/amino acid compound additive and preparation method and application thereof ) 是由 孔晶 王宁 于 2020-12-04 设计创作，主要内容包括：本发明公开了一种粘土/氨基酸复合物添加剂及其制备方法和应用,该复合物添加剂的制备包括如下步骤：将氨基酸溶于缓冲液中,再加入粘土,室温下,将混合液搅拌振荡反应,离心,取上清液,加入水合茚三酮溶液和抗坏血酸溶液,水浴,得到粘土/氨基酸复合物添加剂。本发明制备的粘土/氨基酸复合物添加剂温度耐受性、pH耐受性较自由氨基酸明显升高,有效避免饲料生产加工过程中由于高温等因素引起的氨基酸活性的降低,更有利于饲料生产及储存,适用于温度、pH影响较大的饲料生产加工过程。(The invention discloses a clay/amino acid compound additive and a preparation method and application thereof, wherein the preparation of the compound additive comprises the following steps: dissolving amino acid in buffer solution, adding clay, stirring and oscillating the mixed solution at room temperature for reaction, centrifuging, taking supernatant, adding ninhydrin solution and ascorbic acid solution, and performing water bath to obtain the clay/amino acid composite additive. The temperature tolerance and the pH tolerance of the clay/amino acid compound additive prepared by the invention are obviously higher than those of free amino acid, the reduction of the activity of the amino acid caused by factors such as high temperature and the like in the feed production and processing process is effectively avoided, the production and the storage of the feed are more facilitated, and the clay/amino acid compound additive is suitable for the feed production and processing process with larger influences on temperature and pH.)

1. A method for preparing a clay/amino acid composite additive is characterized by comprising the following steps: dissolving amino acid in buffer solution, adding clay, stirring and oscillating the mixed solution at room temperature for reaction, centrifuging, taking supernatant, adding ninhydrin solution and ascorbic acid solution, and performing water bath to obtain the clay/amino acid composite additive.

2. The method for preparing a clay/amino acid complex additive according to claim 1, wherein the clay is attapulgite, montmorillonite or zeolite powder having a relative density of 2.05 to 2.3.

3. The method for preparing a clay/amino acid complex additive as claimed in claim 1, wherein the amino acid is serine or threonine, and a feeding amino acid or a pure amino acid is used.

4. The method for preparing a clay/amino acid complex additive as claimed in claim 1, wherein the buffer is disodium hydrogen phosphate-citric acid buffer.

5. The method for preparing a clay/amino acid complex additive according to claim 1, wherein 4-6 g of amino acid is added to 100mL of the buffer solution.

6. The method for preparing a clay/amino acid complex additive according to claim 1, wherein the amount of the clay is 0.1 to 0.5 g.

7. The method for preparing a clay/amino acid complex additive as claimed in claim 1, wherein the shaking speed of the stirring and shaking reaction of the mixed solution is 250 to 350r/min, and the time is 25 to 35 min.

8. The method for preparing a clay/amino acid complex additive according to claim 1, wherein the concentrations of ninhydrin and ascorbic acid after the addition of the ninhydrin solution and the ascorbic acid solution to the supernatant solution are preferably 0.1-0.2g/mL and 0.3-0.4g/mL, respectively.

9. A clay/amino acid complex additive prepared by the method of claim 1.

10. Use of the clay/amino acid complex additive prepared by the method of claim 1 in the preparation of a feed additive product.

Technical Field

The invention belongs to the technical field of feed additive application, and particularly relates to a clay/amino acid compound additive and a preparation method and application thereof.

Background

The feed additive is a small amount or trace substance added in the production, processing and using processes of feed, and the feed additive is small in dosage but remarkable in effect. The feed additive is a raw material inevitably used in modern feed industry, and has obvious effects on strengthening the nutritive value of basic feed, improving the production performance of animals, ensuring the health of the animals, saving the feed cost, improving the quality of animal products and the like. The feed additive mainly comprises mineral elements, enzyme preparations, vitamins, amino acids, antibiotics, antioxidants, microorganisms and the like.

The addition of amino acid in the feed is widely applied, and the addition of amino acid can greatly save the protein consumption. Feed formulations have slowly shifted from the traditional energy protein model to the available amino acid model. Practice proves that the feed formula can be designed more scientifically and reasonably by utilizing an amino acid mode. In order to balance and reasonable the proportion of amino acid in the feed formula, the amino acid additive is more convenient and necessary to use. At present, the amino acid feed additive is industrially produced by fermentation, chemical synthesis, enzyme, chemical enzyme and other methods. However, the biological effectiveness and chemical stability of amino acids in feed are influenced by various factors such as antinutritional factors and storage processing conditions in the feed.

Threonine is usually the second or third limiting amino acid in pig feed, is the third or fourth limiting amino acid in poultry feed, and gradually becomes the main limiting factor influencing the production performance of livestock and poultry with the wide application of lysine and methionine synthetic products in compound feed, especially after lysine is added into low-protein daily ration, threonine becomes the first limiting amino acid for breeding pigs. L-threonine is the only amino acid among all amino acids that does not undergo transamination and deoxidation processes in livestock.

Serine is a non-essential amino acid that plays a role in the metabolism of fats and fatty acids and in muscle growth because it contributes to the production of immunocytokines and antibodies, and is also required to maintain a healthy immune system. Serine plays a role in the production and processing of cell membranes, and in the synthesis of muscle tissues and sheaths surrounding nerve cells.

Attapulgite clay is a needle-like nanometer-level natural clay, which is hydrated magnesium silicate composed of double chains Si-O, and is further connected by a layer of octahedral magnesium atoms in a hexa-coordination manner to form a strip network which is only connected together along the edge. ATP has a discontinuous octahedral structure, comprising alternating 2: 1 aluminosilicate modules and hydration channels, which exhibit a hierarchical chain structure, contain many hydroxyl groups on the surface, and can also be easily dispersed in aqueous solutions to form stable colloidal suspensions. Compared with other clay minerals, the clay mineral has excellent performances such as abundant sediments, is widely applied to various fields such as pharmaceutical industry and the like, and also plays an irreplaceable important role as a basic material in the fields of chemical industry, catalysis, environmental protection, new materials and the like.

Montmorillonite is a mineral clay with high economic value, has strong interlayer ion exchange and positioning adsorption capacity, can directionally adsorb pathogenic bacteria with granular coded protein (CS31A) and toxins thereof such as harmful fungi such as vibrio cholerae, campylobacter jejuni, escherichia coli, aflatoxin, gibberellin ketone, mycotic pathogens and the like, loses pathogenicity, promotes the adsorption capacity of gastrointestinal mucosa, and recovers the normal frequency of gastrointestinal peristalsis. Can adsorb heavy metal substances in the feed, and reduce the damage of heavy metal to animal organism.

Zeolites contain almost no water, molecular sieves have high specificity, and are advantageous for adsorptive separation of amino acids. Hydrophobic zeolites such as silicalite and ZSM-5 find use in the separation of carbohydrates and amino acids. The advantages of size selectivity and resistance to swelling of molecular sieves are often used in zeolite powders, pellets and zeolite membranes. In recent years, the development of macroporous zeolite membrane synthesis technology has made it increasingly attractive for steady-state separation of amino acids. Zeolite powder has been used in many industries, such as water purification, catalyst carriers, drug delivery systems, etc., due to its hydrophobic nature and good thermal stability.

At present, more researches are carried out on clay and amino acid as feed additives respectively, the clay and the amino acid are common feed additives, and the clay/amino acid compound additive as the feed additive is not reported for a long time. In the prior art, clay and amino acid are directly mixed and added into feed, amino acid cannot be well protected in the production and processing process of the feed, and the loss of amino acid enzyme activity in different degrees can be caused due to the influence of temperature, humidity, pH and the like in the production and processing process of the feed, so that the exertion of the efficacy of the amino acid is influenced. In addition, new safety problems are easily caused by adding other feed additive types.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problem that the activity of amino acid is reduced because the amino acid is easily damaged in the feed processing production and storage processes, the invention provides a clay/amino acid compound additive and a preparation method thereof.

The invention also provides application of the prepared attapulgite/phytase compound additive.

The technical scheme is as follows: in order to achieve the above object, a method for preparing a clay/amino acid complex additive according to the present invention comprises the steps of: dissolving amino acid in buffer solution, adding clay, stirring and oscillating the mixed solution at room temperature for reaction, centrifuging, taking supernatant, adding ninhydrin solution and ascorbic acid solution, and performing water bath to obtain the clay/amino acid composite additive.

Wherein the clay is attapulgite, montmorillonite or zeolite powder with relative density of 2.05-2.3. Preferably, the attapulgite, montmorillonite or zeolite powder has a relative density of 2.1.

Wherein the amino acid is serine or threonine, and can adopt feeding amino acid or pure amino acid. The feed amino acid or the pure amino acid can be used in the invention, and the feed amino acid is low in price, but the effect is not obvious, so that the pure amino acid is usually selected for application and production. The pure amino acids are serine standard substance and threonine standard substance.

Wherein the buffer solution is disodium hydrogen phosphate-citric acid buffer solution (pH 6.0).

Wherein 4-6 g of amino acid is added into each 100mL of buffer solution. Wherein the amount of the clay is 0.1-0.5 g.

Wherein the oscillation speed of the stirring oscillation reaction of the mixed solution is 250-350 r/min, and the time is 25-35 min. Most preferably at an oscillation rate of 300r/min for a period of 30 min.

Wherein, after the ninhydrin solution and the ascorbic acid solution are added into the supernatant, the concentrations of the ninhydrin and the ascorbic acid are 0.1-0.2g/mL and 0.3-0.4g/mL respectively.

Preferably, the concentrations of ninhydrin and ascorbic acid in the supernatant are 0.1g/mL and 0.3g/mL, respectively. Wherein the water bath is carried out for more than 15min at 100 ℃.

The clay/amino acid compound additive prepared by the preparation method of the clay/amino acid compound additive is provided by the invention.

The clay/amino acid compound additive prepared by the preparation method of the clay/amino acid compound additive is applied to preparing feed additive products.

The invention relates to a clay/amino acid compound biological feed additive prepared by a preparation method of the clay/amino acid compound biological feed additive with clay as a carrier.

The clay/amino acid compound biological feed additive prepared by the preparation method of the clay/amino acid compound biological feed additive taking clay as a carrier is applied to a feed additive product. Is especially suitable for the production and processing process of feed with great influence on temperature and pH.

The clay with the relative density of 2.05-2.3 is prepared by the following specific steps:

(1) and (3) attapulgite purification: grinding the raw materials for 20 minutes, and adding 1g of sample into 100mL of deionized water to disperse the sample; then, ultrasonic treatment is performed to remove sand and large stones, the suspension after ultrasonic treatment is filtered and thoroughly washed with deionized water, the supernatant is removed by centrifugation, and the precipitate is dried for later use. Heavy liquid centrifugal separation: pouring the heavy liquid into a separating funnel, soaking the attapulgite obtained in the step (1) with methanol, slowly pouring the soaked attapulgite, stirring, placing the mixture in a centrifugal separator, taking the attapulgite with the relative density of 2.05-2.3, and drying for later use.

(2) Purifying montmorillonite: soaking crushed montmorillonite raw ore which is sieved by a 150-mesh sieve in water to prepare a suspension with the mass fraction of 20%, dispersing and pulping at a high speed (pulping once every 10 min) for 30min, taking out the slurry, standing and settling for 3h, 10000r/min, centrifuging for 15min, removing supernatant, and drying for later use.

Heavy liquid centrifugal separation: pouring the heavy liquid of the Dudu into a separating funnel, then soaking the montmorillonite obtained in the step (1) with methanol, slowly pouring the mixture into the separating funnel, stirring, placing the mixture in a centrifugal separator, taking the montmorillonite with the relative density of 2.05-2.3, and drying for later use.

(3) Zeolite powder purification: soaking crushed zeolite powder raw ore which is sieved by a 150-mesh sieve in water to prepare a suspension with the mass fraction of 20%, dispersing and pulping at a high speed (pulping once every 10 min) for 30min, taking out the slurry, standing and settling for 3h, 10000r/min, centrifuging for 15min, removing supernatant, and drying for later use.

Heavy liquid centrifugal separation: pouring the heavy liquid into a separating funnel, soaking the zeolite powder obtained in the step (1) with methanol, slowly pouring the soaked zeolite powder, stirring, placing the mixture in a centrifugal separator, taking the zeolite powder with the relative density of 2.05-2.3, and drying for later use.

The method for detecting the adsorption quantity of the amino acid uses an indetrione method to detect the serine content, and the analysis cost is overhigh because the flow required by the high performance liquid chromatography is higher than the requirement of a reagent. The formaldehyde method is only suitable for the structure that the side chain R group of the amino group is a hydroxyl group, and has great limitation. However, all alpha-amino acids can react with ninhydrin, and after the free amino group of the alpha-amino acid reacts with ninhydrin, bluish purple substances such as substituted salts of diketoninhydrin indenamine can be generated. The reaction can make serine with the same concentration have different color shades under different pH conditions, and the total amount of serine in an unknown sample can be calculated according to a standard curve by measuring the light absorption value at 570nm by using a spectrophotometer. The method has short required time, simple operation, economy and feasibility, and is beneficial to large-batch operation treatment.

The clay and the amino acid used in the invention are common feed additives, the clay has a certain adsorption effect, and the adsorption effect of the clay on the amino acid by adopting the method of the invention can ensure the activity of the amino acid to a certain extent, so that the efficacy of the amino acid can be normally exerted, and the loss of the amino acid to different extents caused by the influence of temperature, pH and the like in the production and processing process of the feed is avoided.

The invention selects amino acid and clay as raw materials to prepare the compound feed additive, and avoids the problem of new safety because other new feed additive types are not required to be additionally introduced.

In addition, other factors in the feed processing pelletization process, such as the pelletization time and the water content of the feed, can affect the activity of the amino acid. The amino acid and the clay are fully contacted through the oscillation adsorption effect, the clay has strong adsorbability, and the amino acid is adsorbed to the surface of the clay through the synergistic effect of ion exchange and physical adsorption, so that the clay/amino acid compound is obtained.

The invention aims to apply the clay and the amino acid to the feed together, simultaneously exert the advantages of the clay and the amino acid and reduce the loss of the amino acid, and the clay and the amino acid are not applied to feed processing together through adsorption in other reports.

The raw materials of the invention are all available on the market, wherein, the attapulgite, the montmorillonite and the zeolite powder are purchased from Jiangsu Huazheng mineral products, Inc.; serine standard (pure product) and threonine standard (pure product) were purchased from chemical reagents of national drug group, ltd; serine and threonine for feed were purchased from Zhengxing food additives, Inc. in Henan; dulien heavy liquids (mercuric iodide-potassium iodide solutions) having relative densities of 2.05, 2.1, 2.2, 2.3, etc. were purchased from Shandong Haojie heavy industries, Inc., respectively, and clays having the corresponding relative densities were separated from the heavy liquids.

Has the advantages that: compared with the prior art, the invention has the following advantages:

(1) the main raw materials of the invention are clay and amino acid, which can replace the amino acid directly added in the feed mixing process, and the addition amount is reduced.

(2) The preparation method provided by the invention adopts magnetic stirring and constant-temperature oscillation, the preparation conditions are mild, the process is simple, and the large-scale production is easy to realize.

(3) The clay/amino acid compound biological feed additive with the clay as the carrier prepared by the invention can also provide minerals required by organisms.

(4) The clay/amino acid compound biological feed additive with the clay as the carrier prepared by the invention has obviously higher temperature tolerance and pH tolerance than free amino acid, effectively avoids the reduction of amino acid activity caused by factors such as high temperature and the like in the feed production and processing process, is more beneficial to feed production and storage, and is suitable for the feed production and processing process with larger temperature and pH influences.

(5) The optimum pH medium range of the clay/amino acid compound biological feed additive taking the clay as the carrier prepared by the invention is about 6.0, and is consistent with the optimum active medium pH of amino acid of 5.0-6.5.

(6) The invention takes the clay as a compound adsorption carrier, does not introduce other additional additives and has low price; meanwhile, the clay with the relative density of 2.05-2.3 is selected for treatment, large-particle impurities are removed, the clay under the relative density has good dispersibility and better adsorption effect on the amino acid, and in addition, the pH value of the buffer solution selected by the invention is 6, so that the amino acid can keep better activity under the environment.

(7) The amino acid activity of the clay/amino acid compound biological feed additive which is prepared by the invention and takes the clay as the carrier and is added into the feed is obviously improved compared with the temperature tolerance and the pH tolerance of the clay and the amino acid which are directly added into the feed after simple physical mixing.

(8) The clay/amino acid compound biological feed additive with clay as a carrier prepared by the invention is used as a new formulation of the feed additive, can prepare a safe and effective feed additive product, and simultaneously provides a new idea for the development of the compound feed additive.

Detailed Description

The invention is further illustrated by the following examples.

Example 1

(1) And (3) attapulgite purification: grinding an original attapulgite material for 20 minutes, and adding 1g of a sample into 100mL of deionized water to disperse the sample; then ultrasonic filtration treatment is carried out to remove sand and large stones, the suspension after ultrasonic filtration is thoroughly washed with deionized water, the supernatant is removed by centrifugation, and the precipitate is dried for later use.

(2) Heavy liquid centrifugal separation: pouring 5mL of Du-column heavy liquid (mercuric iodide-potassium iodide solution) with a relative density of 2.1 into a separating funnel, soaking the attapulgite precipitate in methanol for 30min, slowly pouring into the separating funnel, stirring with a glass rod, centrifuging at 1000r/min for 10h, taking attapulgite with a relative density of 2.1, and drying for later use.

(3) Clay/amino acid complex additive: putting 0.1g of attapulgite with the relative density of 2.1 into a beaker at room temperature, adding 100mL of buffer solution of disodium hydrogen phosphate-citric acid with the pH value of 6.0, adding 20mL of aqueous solution containing 5g of serine standard substance, stirring and adsorbing at the rotating speed of 300rpm for 30min, centrifuging, taking supernatant, adding ninhydrin solution and ascorbic acid solution into the supernatant to obtain final concentrations of 0.1g/mL and 0.3g/mL respectively, carrying out water bath at 100 ℃ for 15min, freeze-drying for 12h, crushing, and sieving with a 200-mesh sieve to obtain the compound, namely the attapulgite/serine compound additive.

Example 2

(1) And (3) attapulgite purification: grinding the raw materials for 20 minutes, and adding 1g of sample into 100mL of deionized water to disperse the sample; then ultrasonic filtration treatment is carried out to remove sand and large stones, the suspension after ultrasonic filtration is thoroughly washed with deionized water, the supernatant is removed by centrifugation, and the precipitate is dried for later use.

(2) Heavy liquid centrifugal separation: pouring 5mL of dolichos de-densis heavy liquid (mercuric iodide-potassium iodide solution) with a relative density of 2.05 into a separating funnel, soaking the attapulgite precipitate with methanol for 30min, slowly pouring into the separating funnel, stirring with a glass rod, centrifuging at 1000r/min for 10h, taking attapulgite with a relative density of 2.05, and drying for later use.

(3) Respectively placing 0.1g of attapulgite with the relative density of 2.05 in a beaker at room temperature, adding 100mL of buffer solution of disodium hydrogen phosphate-citric acid with the pH value of 6.0, adding 20mL of aqueous solution containing 5g of serine standard substance, stirring and adsorbing at the rotating speed of 300rpm for 30min, centrifuging, taking supernatant, adding ninhydrin solution and ascorbic acid solution with the final concentrations of 0.1g/mL and 0.3g/mL respectively, carrying out water bath at 100 ℃ for 15min, freeze-drying for 12h, crushing and sieving with a 200-mesh sieve to obtain a compound, namely the attapulgite/serine compound additive.

Example 3

(1) Purifying montmorillonite: taking 1g of montmorillonite raw ore crushed and sieved by a 150-mesh sieve, soaking in water to prepare a suspension with the mass fraction of 20%, dispersing and pulping at a high speed (pulping once every 10 min) for 30min, taking out the slurry, standing and settling for 3h, 10000r/min, centrifuging for 15min, removing supernatant, and drying for later use;

(2) heavy liquid centrifugal separation: pouring 5mL of Dulian heavy liquid (mercuric iodide-potassium iodide solution) with the relative density of 2.1 into a separating funnel, soaking the montmorillonite in methanol for 10min, slowly pouring into the separating funnel, stirring with a glass rod, centrifuging at 1000r/min for 10h, taking the montmorillonite with the relative density of 2.1, and drying for later use;

(3) clay/amino acid complex additive: respectively placing 0.1g of montmorillonite with the relative density of 2.1 in a beaker at room temperature, adding 100mL of buffer solution (disodium hydrogen phosphate-citric acid buffer solution) with the pH value of 6.0, then adding 20mL of serine standard substance containing 5g, stirring and adsorbing, rotating speed of 300rpm, time of 30min, taking supernatant, adding ninhydrin solution and ascorbic acid solution with the final concentrations of 0.1g/mL and 0.3g/mL respectively, carrying out water bath at 100 ℃ for 15min, freeze-drying for 12h, crushing and sieving by 200 meshes to obtain a compound, namely the montmorillonite/serine mesh compound additive.

Example 4

(1) Zeolite powder purification: taking 1g of zeolite powder raw ore crushed and sieved by a 150-mesh sieve, soaking in water to prepare a suspension with the mass fraction of 20%, dispersing and pulping at a high speed (pulping once every 10 min) for 30min, taking out the slurry, standing and settling for 3h, 10000r/min, centrifuging for 15min, removing supernatant, and drying for later use;

(2) heavy liquid centrifugal separation: pouring 5mL of Du-column heavy liquid (mercuric iodide-potassium iodide solution) with the relative density of 2.1 into a separating funnel, soaking the zeolite powder in methanol for 10min, slowly pouring into the separating funnel, stirring with a glass rod, centrifuging at 1000r/min for 10h, taking the zeolite powder with the relative density of 2.1, and drying for later use;

(3) clay/amino acid complex additive: respectively placing 0.1g of zeolite powder with the relative density of 2.1 in a beaker at room temperature, adding 100mL of buffer solution (disodium hydrogen phosphate-citric acid buffer solution) with the pH value of 6.0, then adding 20mL of standard substance containing 5g of serine, stirring and adsorbing, rotating speed of 300rpm, time of 30min, taking supernatant, adding ninhydrin solution and ascorbic acid solution with the final concentrations of 0.1g/mL and 0.3g/mL respectively, carrying out water bath at 100 ℃ for 15min, freeze-drying for 12h, crushing and sieving by a 200-mesh sieve to obtain a compound, namely the zeolite powder/serine compound additive.

Example 5

Example 5 is the same as example 1 except that the serine standard vial was replaced with a threonine standard.

Example 6

Example 6 is the same as example 1, except that the serine standard was replaced with a feeding amino acid.

Example 7

Example 7 was the same as example 3 except that montmorillonite was replaced with montmorillonite having a relative density of 2.3.

Example 8

Example 8 is the same as example 3 except that montmorillonite is replaced with zeolite powder.

Example 9

Example 9 is the same as example 3 except that the serine standard was replaced with the threonine standard.

Example 10

Example 10 is the same as example 4 except that the serine standard vial was replaced with a threonine standard.

Example 11

Example 11 is the same as example 1 except that: 0.5g of attapulgite is used, 6g of serine is added into 100mL of buffer solution, and the concentrations of ninhydrin and ascorbic acid in the supernatant are respectively 0.2g/mL and 0.4 g/mL; the mixed solution is stirred and subjected to oscillation reaction, the oscillation speed is 350r/min, and the time is 25 min.

Example 12

Example 12 is the same as example 1 except that: adding 4g of serine into 100mL of the buffer solution; the mixed solution is stirred and the oscillation speed of the oscillation reaction is 250r/min, and the time is 25 min.

Control group 1

Control 1 was the same as example 1 except that attapulgite having a relative density of 2.0 was replaced with attapulgite having a relative density of 2.0.

Control group 2

Control 2 was the same as example 1 except that attapulgite having a relative density of 2.0 was replaced with attapulgite having a relative density of 2.35.

Control group 3

Control group 3 was the same as example 1 except that the standard serine solution was directly physically mixed with attapulgite to finally obtain a mixed amino acid biological feed additive using attapulgite as a matrix.

Test example 1

Using the method of example 1, the attapulgite was placed in beakers at room temperature, and 100mL of the same volume of disodium hydrogenphosphate-citric acid buffer at different pH values (3.0, 4.0, 5.0, 6.0, 7.0, 8.0) was added to prepare a complex, and the absorbance of the supernatant was measured at 570 nm. And drawing a standard curve of the serine content and the absorbance value. Aims to find out the serine content in the supernatant after the attapulgite adsorbs the serine according to the standard curve. The results are shown in Table 1.

The adsorption amount and the adsorption rate were calculated according to the following formulas.

Adsorption amount q (mg) ═ C₀-C)×V

C₀-initial concentration of serine in the sample solution, mg/mL;

c, measuring the concentration of serine corresponding to the light absorption value in the standard curve in the sample solution in mg/mL;

v-volume of sample solution, mL

Adsorption rate (%) ═ q/m

m-mass of serine, mg;

q-amount of serine adsorbed by Attapulgite mg Table 1 different pH serine adsorption Effect

As is clear from table 1, the adsorption amount of serine by attapulgite changes with the pH, and the optimum pH for the activity of amino acids was 5.0 to 6.5, considering that the adsorption rate of amino acids by attapulgite at pH6 was 83.80% and the adsorption rate of amino acids by attapulgite at pH7 was 64.60%, the optimum pH was selected to be 6.0.

Test example 2

After the complex was prepared by stirring and adsorbing at different rotation speeds (200, 300, 500rpm) by the method of example 1, the absorbance value of the 570nm supernatant was measured, and the adsorption amount and adsorption rate were calculated. The results are shown in Table 2.

TABLE 2 results of the adsorption experiment of the stirring speed to serine

As is clear from Table 2, when the oscillation speed is 300 to 500r/min, the adsorption rate of attapulgite to serine is close, the adsorption rate does not change with the change of the oscillation speed, and the adsorption rate of attapulgite to serine is almost maintained at about 83.80%, so that the oscillation speed is selected to be the most suitable one at 300 r/min.

Test example 3

Using the method of example 1, attapulgite was placed in beakers and stirred at different temperatures (25 ℃, 40 ℃, 60 ℃, 85 ℃) to adsorb, to prepare compounds, and after cooling, absorbance was measured at 570 nm.

TABLE 3 influence of temperature on serine adsorption

From the results in Table 3, it was revealed that the adsorption amount of serine by attapulgite increased with the increase in temperature, but the tendency of the adsorption amount of zeolite powder increased gently when the temperature was > 40 ℃. And when the temperature is 25 ℃, the adsorption rate of the attapulgite on the serine is more than 85 percent, and the experiment can be carried out at room temperature for the consideration of cost saving and operation safety and the consideration of the control of the adsorption temperature condition.

Test example 4

The most suitable temperature of the serine feed is concentrated between 15 ℃ and 80 ℃, and the test mainly determines the desorption rate of the biological feed additive taking attapulgite as a matrix and free pure serine exposed at 80 ℃. 1.0g of the attapulgite/serine complex additive based on attapulgite prepared in example 1 was taken out and exposed to 80 ℃ to measure the desorption rate after 0.50, 2.00 and 4.00 hours, respectively. And (3) pouring 50ml of 4% potassium nitrate solution into the reserved solid sample, uniformly mixing, carrying out adsorption oscillation, centrifuging, taking the supernatant, detecting, and substituting the data into a standard curve equation to calculate the concentration of the serine, thereby obtaining the desorption rate. The temperature tolerance of the free pure serine group, the control group 1, the control group 2 and the control group 3 with equal mass was measured under the same conditions. The results are shown in Table 4. The desorption rate was calculated according to the following formula.

Initial amount of adsorption q₀(mg)＝(C₀-C)×V

C₀-initial concentration of serine in the sample solution, mg/mL;

c, measuring the concentration of serine corresponding to the light absorption value in the standard curve in the sample solution in mg/mL;

v-volume of sample solution, mL

Desorption amount q₁(mg)＝(C-C₁)×V

C, measuring the concentration of serine corresponding to the light absorption value in the standard curve in the sample solution in mg/mL;

C₁-the concentration of serine corresponding to the measured absorbance of the sample solution in the standard curve after exposure,

mg/mL；

v-volume of sample solution, mL

Degree of desorption (%) ═ q₁/q₀

q₁-desorption amount, mg;

q₀initial adsorption quantity, mg

TABLE 4 temperature resistance

Note: the experimental group is the composite additive taking the attapulgite prepared in the example 1 as the matrix, the free pure amino acid group is the pure amino acid, and the comparison group 1 is the composite additive taking the attapulgite prepared in the example 1 as the matrix, except that the attapulgite with the relative density of 2.0 is selected as the raw material; the control group 2 was a composite additive containing attapulgite as a matrix, which was prepared in example 1, except that attapulgite having a relative density of 2.35 was used as a raw material; the control group 3 was a mixture of attapulgite and pure serine directly mixed physically.

The control 1 and the control 2 were higher in desorption rate, mainly because the attapulgite in the relative density contained many large-particle impurities, and the dispersibility of the attapulgite in the relative density was poor, and the adsorption amount of serine under the conditions was relatively small, which was not the same as that in the experimental group of example 1 of the present invention.

As can be seen from table 4, the desorption rates of the control group 3 at these three time points are all higher than that of the attapulgite-based composite additive under the high temperature condition of 80 ℃, because the attapulgite and the serine are directly and physically mixed without environment that the attapulgite adsorbs the serine, and the adsorption cannot be effectively performed, and simultaneously, the direct physical mixing is easy to destroy the structure of the amino acid, so that the desorption rate is higher than that of the free pure amino acid, if the attapulgite and the serine are directly added into the feed, the serine cannot be well protected in the feed production and processing process, and the serine is lost to different degrees due to the temperature influence in the feed production and processing process.

Test example 5

1.0g of the attapulgite/serine complex additive based on attapulgite prepared in example 1 was taken out and treated for 0.5h at pH4, 5, 6 and 7 of the buffer respectively, and the desorption rate was measured. And pouring the potassium nitrate solution into the reserved solid sample, uniformly mixing, carrying out adsorption oscillation, centrifuging, taking the supernatant for detection, and substituting the data into a standard curve equation to calculate the concentration of the serine, thereby obtaining the desorption rate. The pH tolerance of the free pure serine group, the control group 1 and the control group 2 was measured under the same conditions. The results are shown in Table 5.

TABLE 5PH tolerance

Note: the experimental group was the attapulgite/serine composite additive with the attapulgite as the matrix prepared in example 1, the free pure serine group was pure serine, and the control group 1 was the composite additive with the attapulgite as the matrix prepared in example 1, except that the attapulgite with the relative density of 2.0 was used as the raw material; the control group 2 was a composite additive in which the attapulgite prepared in example 1 was used as a matrix, except that the attapulgite having a relative density of 2.35 was used as a raw material,

as shown in Table 5, the optimum pH of the medium for the attapulgite/serine complex additive having attapulgite as a matrix was about 6.0 under the same conditions. The pH value of the gastrointestinal tract of livestock and poultry is generally 3.5-7.0, and the results prove that the attapulgite-based biological feed additive can play an active role in the gastrointestinal tract environment, and the desorption rate of the experimental results of a control group is higher than that of the attapulgite-based biological feed additive of the experimental group of the embodiment 1, because the attapulgite has higher or lower relative density and contains a lot of large-particle impurities, and the attapulgite has poor dispersibility under the relative density, so that the adsorption capacity to serine is relatively small under the condition. Since the optimum medium pH is mainly an evaluation index for each complex, the test example does not relate to a control experiment using a mixture of attapulgite and a pure serine product which are physically mixed.

From the results of table 5, it is understood that serine is hardly completely desorbed from the adsorbed attapulgite at various pH values as a whole. And when the pH value is 6.0, the desorption rate is lower than that of other pH values, which shows that the attapulgite can adsorb serine into the attapulgite to a greater extent and can protect the serine from being damaged by the pH environment.

In addition, in the preparation of the composites of serine and montmorillonite/zeolite powder, threonine and attapulgite/montmorillonite/zeolite powder, the same method as in the above experimental examples was employed, and it was concluded that they were similar to serine/attapulgite.