Application of mannose polysaccharide with specific molecular weight in preparation of feed and preparation method of feed additive

Abstract

The invention belongs to the technical field of feed additives, and discloses application of specific molecular weight mannose polysaccharide in feed preparation and a preparation method of the feed additive, and the new application is that the specific molecular weight mannose polysaccharide with the weight-average molecular weight of 19-170 kDa is used as an additive and is added into poultry feed according to the addition amount which is 0.5-2% of the total weight of the poultry feed. The mannopolysaccharide with specific molecular weight improves the growth performance of the broiler chickens by reducing the feed-weight ratio of the broiler chickens, improves physiological and biochemical indexes by reducing the levels of glutamic-pyruvic transaminase and glutamic oxalacetic transaminase and the like, and improves the immunocompetence by improving the levels of IgG and IgA, so that the broiler chickens grow healthily, and the mannopolysaccharide feed additive is simple in preparation method, low in cost and suitable for industrial production. The preparation method comprises the following steps: performing autolysis and high-temperature extraction on yeast to obtain crude mannose polysaccharide, and performing deproteinization, decoloration, alcohol precipitation and chromatographic purification to obtain the mannose polysaccharide. The method is suitable for preparing the poultry feed additive.

Description

Technical Field

[0001] The invention belongs to the technical field of feed additives, in particular to the application of mannopolysaccharide with a specific molecular weight in preparing feed and a method for preparing the feed additive. Background Art

[0002] Excessive use of antibiotics in poultry farming may, on the one hand, cause pathogenic microorganisms to develop drug resistance, increasing the risk of super pathogens and viruses; on the other hand, improper addition of antibiotics may also cause an imbalance in the intestinal flora of poultry, causing intestinal damage, which is not conducive to intestinal nutrient absorption and feed digestion in poultry, affecting production and even endangering food safety. Therefore, finding alternatives to antibiotics or developing feed additives that enhance poultry immunity has become a hot research direction.

[0003] Among many feed additives, mannosan plays an outstanding role in promoting intestinal health and enhancing immunity. Among them, low molecular weight mannosan is often used as a feed immunopotentiator. For example, the Chinese invention patent application with publication number CN118901908A discloses a shrimp feed synergist containing low molecular weight mannosan. However, the differences in molecular structure of mannosans with different molecular weights make their effects not exactly the same. The direct application of low molecular weight mannosans used in shrimp feed to poultry farming cannot achieve similar effects due to the differences in feeding environment, physiological structure and nutritional requirements of different feeding objects. In addition, some low molecular weight mannosans are prepared by enzymatic hydrolysis of mannosans, and there is a problem that the preparation cost is higher than that of mannosans. Summary of the invention

[0004] In order to solve the above deficiencies in the prior art, the present invention aims to provide a feed additive of mannosan with a specific molecular weight. The inventor unexpectedly found that mannosan with a weight average molecular weight of 19 to 170 kDa, but not other molecular weights, can be used in poultry feed to promote poultry growth performance and improve immunity, especially to significantly improve broiler feed conversion rate and immune index IgG;

[0005] Another object of the present invention is to provide a preparation method and application of the above-mentioned specific molecular weight mannan polysaccharide feed additive, so as to improve the preparation efficiency, reduce the production cost, and be suitable for adding to poultry feed.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] The invention discloses an application of mannoses with a specific molecular weight in preparing feeds, wherein the mannoses with a specific molecular weight having a weight average molecular weight of 19 to 170 kDa are added to poultry feeds as an additive.

[0008] As a limitation of the present invention, the addition amount of the specific molecular weight mannosan is 0.5% to 2% of the total weight of the poultry feed.

[0009] As a further limitation of the present invention, the poultry feed is broiler feed.

[0010] The invention also provides a mannosan feed additive with a specific molecular weight, which is a mannosan with a weight average molecular weight of 19 to 170 kDa.

[0011] The present invention also provides a method for preparing a mannosan feed additive with a specific molecular weight, which comprises taking yeast and subjecting it to autolysis and high-temperature extraction to obtain crude mannosan, and then subjecting it to protein removal, decolorization, alcohol precipitation and chromatography purification to obtain the mannosan feed additive with a specific molecular weight.

[0012] As another limitation of the present invention, the temperature of high temperature extraction is 110° C. to 125° C.; and the protein is removed by using trichloroacetic acid accounting for 4% to 6% of the weight of the crude mannopolysaccharide.

[0013] Among them, the protein removal methods using Sevage method and trichloroacetic acid method were compared, and it was unexpectedly found that the protein removal effect of trichloroacetic acid method exceeded expectations.

[0014] As a further limitation of the present invention, the decolorization is carried out by using activated carbon, and the decolorization is followed by spray drying to make the solid for easy storage.

[0015] The mannan polysaccharide from which the protein has been removed is decolorized by a hydrogen peroxide method or an activated carbon method, wherein the activated carbon method has a better decolorization effect.

[0016] The present invention also provides the use of the above-mentioned specific molecular weight mannan polysaccharide feed additive, which is used for adding to feed to reduce the feed-to-weight ratio of poultry and improve biochemical indicators and immune indicators.

[0017] As a further limitation of the present invention, the biochemical indexes include the content of aspartate aminotransferase (AST), triglyceride (TG) and alanine aminotransferase (ALT) in poultry serum; the immune indexes include the content of immunoglobulin G (IgG). Specifically, the above biochemical indexes are reduced and the above immune indexes are increased.

[0018] As a further limitation of the present invention, the compound is used for adding to feed to reduce the feed-to-weight ratio of poultry to ≤6.4, so that the content of aspartate aminotransferase in poultry serum is ≤232.52U / G, the content of triglyceride is ≤0.43mmol / L, the content of alanine aminotransferase is ≤23.22U / G, and the content of immunoglobulin G is ≥3.03mg / ml.

[0019] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0020] The present invention is the first to discover a new use of a specific molecular weight mannan polysaccharide with a weight average molecular weight of 19 to 170 kDa. Adding it to poultry feed as an additive can significantly reduce the feed-to-weight ratio of poultry, reduce biochemical indicators such as aspartate aminotransferase (AST), triglycerides (TG) and alanine aminotransferase (ALT) in serum, and significantly increase the content of immune indicator IgG.

[0021] The preparation method of the specific molecular weight mannosan polysaccharide feed additive of the present invention is simple and efficient, low in price, and has low application toxicity. The prepared specific molecular weight mannosan polysaccharide feed additive is added to the basic diet of broilers for use, and the growth performance of broilers is improved by reducing the feed-to-weight ratio of broilers, the AST and ALT levels are reduced to improve physiological and biochemical indicators, and the IgG and IgA levels are increased to improve the immune capacity, thereby making the broilers grow healthier.

[0022] The specific molecular weight mannosan feed additive of the present invention has significantly improved economic benefits compared with additives such as low molecular weight mannosan that need to be further enzymatically hydrolyzed from mannosan.

[0023] The invention is suitable for industrial production of poultry feed additives. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a graph showing the results of AST content detection in the application effect detection of Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0025] Figure 2 This is a graph showing the results of TG content detection in the application effect detection of Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0026] Figure 3 This is a graph showing the results of ALT content detection in the application effect detection of Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0027] Figure 4 This is a graph showing the results of GLU content detection in the application effect detection of Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0028] Figure 5 This is a graph showing the results of IgG content detection in the application effect detection of Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0029] Figure 6 This is a graph showing the results of IgA content detection in the application effect detection of Examples 1-3 and Comparative Examples 1-2 of the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below through the accompanying drawings and specific embodiments. It should be understood that the described embodiments are only used to explain the present invention, but not to limit the present invention.

[0031] Example 1 Specific molecular weight mannopolysaccharide feed additive MOS-1 and its preparation method

[0032] The specific molecular weight mannan polysaccharide feed additive MOS-1 is a mannan polysaccharide with a weight average molecular weight of 170 kDa. The specific preparation method thereof is as follows:

[0033] (1) Commercially available yeast powder is added to deionized water to form a bacterial suspension with a mass fraction of 30%, and the suspension is placed in a 37°C incubator for 50 hours to allow the suspension to autolyze. After the autolysis is completed, the precipitate is collected by centrifugation, washed with deionized water three times, and then deionized water is added to form a bacterial suspension, which is subjected to high-temperature extraction at 121°C for 8 hours. After the high-temperature extraction is completed, the supernatant is collected by centrifugation to obtain crude mannopolysaccharide, i.e., a crude mannopolysaccharide extract;

[0034] (2) Protein removal: add trichloroacetic acid (6% by weight of crude mannan polysaccharide) to the crude extract of mannan polysaccharide and stir at 60°C for 40 min to remove protein;

[0035] (3) Decolorization: Add 1% activated carbon to the crude extract of mannan polysaccharide and stir at 40°C for 50 min for decolorization;

[0036] (4) spray drying: spray drying the treated mannosan solution to obtain mannosan solid powder;

[0037] (5) Alcohol precipitation: take the mannosan solid powder and add deionized water to obtain a mannosan aqueous solution with a mass volume ratio of 20% (i.e., mannosan solid mass / deionized water volume = 20%), add anhydrous ethanol to it so that the volume fraction of ethanol in the solution is 50% (i.e., ethanol volume / (ethanol volume + mannosan aqueous solution volume) = 50%), and let it stand overnight at 4°C;

[0038] (6) Chromatographic purification: Collect the precipitate by centrifugation, add deionized water and stir evenly, add it to a gel column filled with polysaccharide gel G-150 for chromatography purification to obtain mannan with a weight average molecular weight of 170 kDa, which is the specific molecular weight mannan feed additive MOS-1.

[0039] Example 2 Specific molecular weight mannopolysaccharide feed additive MOS-2 and its preparation method

[0040] The specific molecular weight mannan polysaccharide feed additive MOS-2 is a mannan polysaccharide with a weight average molecular weight of 96 kDa. The preparation method thereof is substantially the same as that of Example 1, except that in step (2), the amount of trichloroacetic acid used is 5% of the weight of the crude mannan polysaccharide; and in step (5), anhydrous ethanol is added to make the volume fraction in the solution 60%.

[0041] Example 3 Specific molecular weight mannopolysaccharide feed additive MOS-3 and its preparation method

[0042] The specific molecular weight mannan polysaccharide feed additive MOS-3 is a mannan polysaccharide with a weight average molecular weight of 19 kDa. The preparation method thereof is substantially the same as that of Example 1, except that in step (2), the amount of trichloroacetic acid used is 4% of the weight of the crude mannan polysaccharide; and in step (5), anhydrous ethanol is added so that the volume fraction of ethanol in the solution is 70%.

[0043] Comparative Example 1 Mannopolysaccharide feed additive MOS-4 and its preparation method

[0044] Mannosan feed additive MOS-4 is a mannosan with a weight average molecular weight of 291 kDa. Its preparation method is basically the same as that of Example 1, except that in step (5), anhydrous ethanol is added to make the volume fraction of ethanol in the solution 30%.

[0045] Comparative Example 2 Mannopolysaccharide feed additive MOS-5 and its preparation method

[0046] Mannosan feed additive MOS-5 is a mannosan with a weight average molecular weight of 7.7 kDa. Its preparation method is basically the same as that of Example 1, except that in step (5), anhydrous ethanol is added to make the volume fraction of ethanol in the solution 90%.

[0047] Example 4 Application of specific molecular weight mannopolysaccharide feed additive

[0048] Specific molecular weight mannopolysaccharide feed additives MOS-1 to MOS-3 with weight average molecular weights of 19 kDa, 96 kDa and 170 kDa were respectively used as additives and added to the basic daily diet feed of broilers at 0.5% of the total weight of poultry feed.

[0049] Among them, the basic diet composition is: 63.45% corn, 28% soybean meal, 0.5% bran, 1.83% corn gluten meal, 1.55% calcium hydrogen phosphate, 1.4% shell powder, 2.2% soybean oil, 0.2% salt, 0.17% methionine and 0.7% premix.

[0050] Comparative Example 3 Application of Mannosan Feed Additive

[0051] Mannosan feed additives MOS-4 and MOS-5 with weight average molecular weights of 291 kDa and 7.7 kDa were used as additives, respectively, and added to the basal diet feed of broiler chickens at 0.5% of the total weight of poultry feed.

[0052] Application effect detection experiment:

[0053] The feed additives prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to broiler model tests to analyze their effects on the growth performance and biochemical immune indicators of broilers. The details are as follows:

[0054] Three-week-old SPF+ broilers with similar body weight and good health were selected and divided into 6 groups according to the principle of equal distribution of male and female broilers with similar body weight, namely CK group (no mannan polysaccharide added to the basic diet), MOS-1 group (basic diet + 0.5% MOS-1), MOS-2 group (basic diet + 0.5% MOS-2), MOS-3 group (basic diet + 0.5% MOS-3), MOS-4 group (basic diet + 0.5% MOS-4), MOS-5 group (basic diet + 0.5% MOS-5), with five replicates in each group. The room was well ventilated, the room temperature was maintained at 22℃-25℃, and food and water were freely available. The body weight and feed intake of broilers were recorded daily, and the feed-to-weight ratio was calculated. After feeding, the biochemical and immune indicators of broiler serum were measured.

[0055] The results are as follows:

[0056] (1) Material-to-weight ratio test results

[0057] Table 1 Feed-to-weight ratio of broiler chickens

[0058] Group Material weight ratio CK 6.89±0.13 MOS-1 6.3±0.1 MOS-2 6.22±0.08 MOS-3 6.26±0.03 MOS-4 7.06±0.11 MOS-5 6.43±0.15

[0059] As shown in Table 1, by comparing MOS-1, MOS-2, and MOS-3 groups with other groups, it can be seen that adding specific molecular weight mannan (molecular weight of 19-170 kDa) to feed can reduce the feed-to-weight ratio of broilers, making the feed-to-weight ratio ≤6.4, promote the growth and development of broilers, and improve feed conversion rate.

[0060] (2) Results of biochemical and immune index measurements

[0061] Table 2 Results of biochemical and immune indexes

[0062]

[0063] The results of the determination of serum biochemical and immune indicators of broiler chickens are shown in Table 1 and Figure 1-Figure 6 As shown, Figure 1 This is the result of AST content detection. Figure 2 This is the result of TG content detection. Figure 3This is the ALT content test result chart. Figure 4 This is the GLU content detection result diagram. Figure 5 This is the result of IgG content detection. Figure 6 This is the result of IgA content detection. In the figure, * represents P≤0.05; ** represents P≤0.01.

[0064] Depend on Figures 1 to 6 It can be seen that compared with the control group and the comparative example, the specific molecular weight mannan polysaccharide feed additives MOS-1, MOS-2, and MOS-3 prepared in Examples 1 to 3 of the present invention can significantly reduce the levels of biochemical indicators AST and TG, significantly reduce the level of ALT, and significantly increase the level of immune indicator IgG; MOS-1, MOS-2, and MOS-3 groups can increase the level of GLU and IgA compared with the control group. The application of Examples 1 to 3 of the present invention makes the content of aspartate aminotransferase in broiler serum ≤232.52U / G, the content of triglyceride ≤0.43mmol / L, the content of alanine aminotransferase ≤23.22U / G, and the content of immunoglobulin G ≥3.03mg / ml.

[0065] The above results show that adding a certain amount of mannoses with a specific molecular weight rather than other molecular weights to feed can promote the growth performance and immunity of broilers, and play a positive role in the growth and development of broilers. Therefore, the present invention selects a specific molecular weight mannoses with a significant effect on the growth of broilers and combines it with the basic feed to replace antibiotics to a certain extent and promote the development of healthy breeding.

[0066] In other embodiments, the specific molecular weight mannan polysaccharide feed additive is a mannan polysaccharide with a weight average molecular weight of 23kDa, 76kDa, 168kDa, 165kDa or 169kDa; obtained by high temperature extraction at a temperature of 110°C, 115°C, 118°C, 120°C or 125°C; and added to poultry feed as an additive in an amount of 0.6%, 0.8%, 0.75%, 1% or 2% of the total weight of poultry feed. It has been verified that the application effects similar to those of Example 1 are achieved.

[0067] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. An application of mannosan with a specific molecular weight in preparing feed, characterized in that: Mannopolysaccharides with a specific molecular weight of 19-170 kDa were added to poultry feed as an additive.

2. The use of the specific molecular weight mannan polysaccharide according to claim 1 in preparing feed, characterized in that: The addition amount of the specific molecular weight mannopolysaccharide is 0.5% to 2% of the total weight of the poultry feed.

3. The use of the specific molecular weight mannan polysaccharide according to claim 1 or 2 in preparing feed, characterized in that: The poultry feed is broiler feed.

4. A specific molecular weight mannopolysaccharide feed additive, characterized in that: It is a mannopolysaccharide with a weight average molecular weight of 19~170 kDa.

5. A method for preparing the specific molecular weight mannosan feed additive according to claim 4, characterized in that: The yeast is autolyzed and extracted at high temperature to obtain crude mannopolysaccharide, and then the mannopolysaccharide feed additive with specific molecular weight is obtained through protein removal, decolorization, alcohol precipitation and chromatography purification.

6. The method for preparing a specific molecular weight mannosan feed additive according to claim 5, characterized in that: The temperature of high temperature extraction is 110°C~125°C; trichloroacetic acid accounting for 4%~6% of the weight of crude mannopolysaccharide is used to remove protein.

7. The method for preparing a specific molecular weight mannosan feed additive according to claim 5 or 6, characterized in that: The decolorization is carried out by using activated carbon, and spray drying is performed after decolorization.

8. An application of a specific molecular weight mannosan feed additive prepared according to any one of claims 5 to 7, characterized in that: Used to add to feed to reduce the feed-to-weight ratio of poultry and improve biochemical and immune indicators.

9. The use of the specific molecular weight mannosan feed additive according to claim 8, characterized in that: The biochemical index includes the content of aspartate aminotransferase, triglyceride and alanine aminotransferase in poultry serum; the immune index includes the content of immunoglobulin G.

10. The use of the specific molecular weight mannosan feed additive according to claim 9, characterized in that: It is used to add to feed to reduce the feed-to-weight ratio of poultry to ≤6.4, so that the content of aspartate aminotransferase in poultry serum is ≤232.52U / G, the content of triglyceride is ≤0.43mmol / L, the content of alanine aminotransferase is ≤23.22U / G, and the content of immunoglobulin G is ≥3.03mg / ml.

Images