A complex enzyme preparation and a method for preparing the same

Abstract

The application discloses a kind of composite enzyme preparation and preparation method thereof, it is related to enzyme preparation technical field.The composite enzyme preparation of the application at least includes the following weight parts of component: xylanase 10-30 parts, modified cellulase 15-35 parts, glucanase 8-20 parts, protease 5-15 parts, amylase 5-18 parts, pectinase 3-12 parts, phytase 5-25 parts, modified superoxide dismutase composite microsphere 15-40 parts.The composite enzyme preparation provided in the application is added in the daily ration of ruminant, can improve the apparent digestibility of ruminant to nutrient and growth performance, while more safe quality better meat quality can be obtained, improve meat taste, obtain higher economic value.

Description

Technical Field

[0001] This invention relates to the field of enzyme preparation technology, specifically to a compound enzyme preparation and its preparation method. Background Technology

[0002] The shrinking arable land area has led to a shortage of feed resources, thus affecting the development of livestock production. Improving feed utilization has become a major issue in livestock farming. Since the ban on antibiotics, the addition of compound enzymes to livestock diets to improve production performance has been widely used. Enzyme preparations, as a green and efficient new type of feed additive, can improve livestock production performance, increase feed utilization efficiency, and reduce pollution. They have played a crucial role in fundamentally improving beef cattle production efficiency and have also provided a wider range of feed ingredient selection options. Enzyme preparations are now widely used in poultry farming as feed additives. Different types of enzyme preparations play their unique roles in feed, improving nutrient utilization and poultry growth performance: cellulase and pectinase can effectively break down plant cell walls, releasing nutrients from inside the cells, thereby increasing nutrient utilization; β-glucanase and xylanase focus on breaking down anti-nutritional factors in feed, reducing the anti-nutritional effects of non-starch polysaccharides on poultry, and improving feed digestibility and absorption efficiency; protease and amylase can compensate for the deficiency of endogenous enzymes in poultry, helping poultry to digest and utilize proteins and starches more effectively, promoting growth and development.

[0003] Different enzyme preparations have synergistic effects. Compound enzyme preparations are made by mixing different types of enzymes in appropriate proportions, allowing each component to function better. Currently, adding compound enzyme preparations in different proportions has become a common practice in modern poultry farming. The complex structure of roughage cell walls, with cellulose and lignin creating a "cage" effect, hinders the digestion and absorption of feed by ruminants. Therefore, breaking the "cage" effect of cellulose and lignin in production and improving the utilization rate of roughage in ruminants is crucial. Research on the application of fiber compound enzymes has focused on monogastric animals such as pigs and chickens, and many studies have confirmed that fiber compound enzymes have significant and positive effects on improving feed efficiency and production performance, enhancing digestive and absorptive functions, improving feed nutritional value, regulating metabolism, and improving disease resistance. However, research on the application of fiber compound enzymes in ruminant farming started relatively late. Because fibrous decomposition activity in the rumen is very active, simply adding exogenous enzyme preparations will not increase fibrous decomposition activity. Therefore, existing compound enzyme preparations suffer from defects such as easy decomposition and inactivation, and poor digestive effects, which greatly limits the use of this technology. Summary of the Invention

[0004] The purpose of this invention is to provide a compound enzyme preparation and its preparation method, thereby solving the following technical problems:

[0005] Existing compound enzyme preparations used in ruminant feed suffer from problems such as easy decomposition and inactivation, and poor digestive effects.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A complex enzyme preparation comprising at least the following components in parts by weight:

[0008] Xylanase 10-30 parts, modified cellulase 15-35 parts, dextranase 8-20 parts, protease 5-15 parts, amylase 5-18 parts, pectinase 3-12 parts, phytase 5-25 parts, modified superoxide dismutase composite microspheres 15-40 parts.

[0009] As a further aspect of the present invention: the modified cellulase is a polyethylene glycol-modified cellulase, and the superoxide dismutase is a polydopamine-chitosan-polylactic acid-hydroxyglycolic acid-superoxide dismutase composite microsphere.

[0010] As a further aspect of the present invention, the preparation method of the modified superoxide dismutase composite microspheres includes the following steps:

[0011] A sodium alginate solution of superoxide dismutase was added to isooctane, followed by an emulsifier. After homogenization, calcium chloride solution and isoacetone were added to obtain the superoxide dismutase core layer.

[0012] The superoxide dismutase core layer was added to an acetonitrile solution of polylactic acid-hydroxyglycolic acid, and then added to peanut oil to obtain polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules.

[0013] The polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules were added to a chitosan solution and incubated to obtain chitosan-polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules.

[0014] The chitosan-polylactic acid hydroxyglycolic acid-superoxide dismutase microcapsules were added to tris(hydroxymethyl)aminomethane hydrochloride buffer, and then dopamine hydrochloride was added to obtain modified superoxide dismutase composite microspheres.

[0015] As a further aspect of the present invention: the mass ratio of the superoxide dismutase core layer to the polylactic acid hydroxyglycolic acid is 1:5-7.

[0016] As a further aspect of the present invention: the mass ratio of the polylactic acid hydroxyglycolic acid-superoxide dismutase microcapsules to the chitosan is 1:0.3-1.2.

[0017] As a further aspect of the present invention: the mass ratio of the chitosan-polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules to the dopamine hydrochloride is 1:0.01-0.05.

[0018] As a further aspect of the present invention: the method for preparing the modified cellulase includes at least the following steps:

[0019] A polyethylene glycol solution was added to a cellulase solution and dried to obtain modified cellulase.

[0020] As a further aspect of the present invention: the degree of polymerization of the polyethylene glycol is 2000-8000, and the mass ratio of the polyethylene glycol to the cellulase is 1-20:100.

[0021] A method for preparing a complex enzyme preparation includes at least the following preparation steps:

[0022] Xylanase, modified cellulase, glucanase, protease, amylase, pectinase, phytase and modified superoxide dismutase composite microspheres are added to a mixer, mixed evenly and then pressed into shape to obtain a composite enzyme preparation.

[0023] The beneficial effects of this invention are:

[0024] The compound enzyme preparation of this invention comprises at least xylanase, modified cellulase, glucanase, protease, amylase, pectinase, phytase, and modified superoxide dismutase composite microspheres. Through the synergistic effect of multiple enzymes, the addition of cellulase, pectinase, xylanase, and β-glucanase to the diet can disrupt the cell wall structure of plant-based raw materials, increase the contact area between rumen microorganisms and feed, enhance rumen fiber digestibility, improve the digestibility of various substances in the diet, thereby improving feed conversion rate, promoting the degradation and absorption of non-starch polysaccharides such as cellulose, xylan, and pectin, and improving the nutritional value of feed during rumen fermentation, thus improving the overall digestibility and absorption of feed by animals. Simultaneously, the exogenous enzyme preparation can also cooperate with endogenous enzymes to enhance the adhesion of microorganisms to feed particles. The compound enzyme preparation prepared in this invention, when added to the diet of ruminants, can effectively improve the activity of endogenous enzymes in the rumen, thereby improving the apparent digestibility of nutrients and growth performance of ruminants.

[0025] This invention modifies cellulase by physically coating it with polyethylene glycol (PEG). The PEG-coated cellulase exhibits enhanced enzyme activity and stability. PEG coating prolongs the enzyme's action time. PEG remains stable in the acidic environment of the rumen and gradually dissolves in the intestine, increasing the release rate and thus enhancing cellulose breakdown and feed digestibility. The hydrogen bonds and hydrophobic interactions between PEG and cellulase buffer thermal shock, protect the enzyme's spatial structure, and reduce thermal inactivation during feed processing. Furthermore, the PEG-coated cellulase poses no risk of toxic residues, does not disrupt the rumen microbial community balance, and the preparation method is simple, low-cost, and suitable for large-scale production.

[0026] This invention also incorporates superoxide dismutase (SOD) into its compound enzyme preparation. The SOD is prepared as modified SOD composite microspheres, forming a four-layer encapsulation structure of polydopamine, chitosan, polylactic-hydroxyglycolic acid (PLGA), calcium alginate, and SOD. This structure protects the activity of SOD while allowing it to be slowly released as the polymer degrades, exhibiting high stability and heat resistance. In the rumen stage, the calcium alginate and PLAG layers provide SOD with resistance to acidic environments and slow-release capabilities, preventing rapid inactivation and loss of antioxidant function due to direct exposure in the rumen. In the intestinal stage, the calcium alginate and PLAG layers degrade, while the chitosan and polydopamine layers provide adhesion, improving SOD absorption. This enhances feed conversion ratio, strengthens immunity, eliminates harmful free radicals, prevents disease, and is safe with no side effects. This invention involves preparing a composite enzyme preparation from modified superoxide dismutase (SOD) microspheres and adding it to the diets of ruminants. This increases SOD levels in poultry through both exogenous supplementation and endogenous stimulation, reducing antibiotic use, enhancing stress resistance, improving nutrient absorption, and increasing disease resistance and survival rates in ruminants, thus reducing the likelihood of illness. Simultaneously, it yields safer and higher-quality poultry meat, improves meat texture and taste, and achieves higher economic value. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1: The preparation method of modified superoxide dismutase composite microspheres includes the following steps:

[0029] 80 mg of superoxide dismutase with an enzyme activity of 30,000 U / g was dissolved in phosphate buffer containing 1 wt% sodium alginate. The solution was then added to isooctane containing 6 wt% Span 80 at a volume ratio of 1:2. After high-speed homogenization for 3 min, Tween 80 was added dropwise and homogenized for another 3 min. Then, 8 wt% calcium chloride solution was added dropwise and homogenized for another 3 min. Finally, isopropanol was added and homogenized for another 3 min at the same speed. The solution was then centrifuged, washed, and freeze-dried to obtain the superoxide dismutase core layer.

[0030] 400 mg of polylactic acid glycolic acid was dissolved in 10 mL of acetonitrile, and the superoxide dismutase core layer prepared above was added. After sonication at 100 W for 20 s, the mixture was added dropwise to peanut oil containing 6 wt% Span 80 while stirring at 600 r / min. The stirring speed was then increased to 1000 r / min and stirred for 2 min. Acetonitrile was removed by rotary evaporation under reduced pressure. The mixture was washed with petroleum ether and evaporated at 37 °C to obtain polylactic acid glycolic acid-superoxide dismutase microcapsules.

[0031] The polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules were added to 0.5 wt% chitosan solution and incubated for 30 min. After centrifugation, the microcapsules were collected, washed once with the chitosan solution and then twice with water. They were then freeze-dried. The mass ratio of polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules to chitosan was 1:0.8 to obtain chitosan-polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules.

[0032] The chitosan-poly(lactic-co-hydroxyglycolic acid)-superoxide dismutase microcapsules were added to a tris(hydroxymethyl)aminomethane hydrochloride buffer solution with a pH of 8.5, and then a dopamine hydrochloride solution with a concentration of 2 mg / mL was added. The mixture was magnetically stirred at 300 r / min for 24 h, and then 0.1 mol / L hydrochloric acid solution was added to adjust the pH to 6. The mixture was washed and freeze-dried. The mass ratio of chitosan-poly(lactic-co-hydroxyglycolic acid)-superoxide dismutase microcapsules to dopamine hydrochloride was 1:0.03, thus obtaining modified superoxide dismutase composite microspheres.

[0033] Example 2: The preparation method of modified superoxide dismutase composite microspheres includes the following steps:

[0034] 80 mg of superoxide dismutase with an enzyme activity of 30,000 U / g was dissolved in phosphate buffer containing 1 wt% sodium alginate. The solution was then added to isooctane containing 6 wt% Span 80 at a volume ratio of 1:2. After high-speed homogenization for 3 min, Tween 80 was added dropwise and homogenized for another 3 min. Then, 8 wt% calcium chloride solution was added dropwise and homogenized for another 3 min. Finally, isopropanol was added and homogenized for another 3 min at the same speed. The solution was then centrifuged, washed, and freeze-dried to obtain the superoxide dismutase core layer.

[0035] 500 mg of polylactic acid glycolic acid was dissolved in 12 mL of acetonitrile, and the superoxide dismutase core layer prepared above was added. After sonication at 100 W for 20 s, the mixture was added dropwise to peanut oil containing 6 wt% Span 80 while stirring at 600 r / min. The stirring speed was then increased to 1000 r / min and stirred for 2 min. The mixture was then subjected to rotary evaporation under reduced pressure to remove acetonitrile, washed with petroleum ether, and evaporated at 37 °C to obtain polylactic acid glycolic acid-superoxide dismutase microcapsules.

[0036] The polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules were added to 0.8 wt% chitosan solution and incubated for 30 min. After centrifugation, the microcapsules were collected, washed once with the chitosan solution and then twice with water. They were then freeze-dried. The mass ratio of polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules to chitosan was 1:1 to obtain chitosan-polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules.

[0037] The chitosan-poly(lactic-co-hydroxyglycolic acid)-superoxide dismutase microcapsules were added to a tris(hydroxymethyl)aminomethane hydrochloride buffer solution with a pH of 8.5, and then a dopamine hydrochloride solution with a concentration of 2 mg / mL was added. The mixture was magnetically stirred at 300 r / min for 24 h, and then 0.1 mol / L hydrochloric acid solution was added to adjust the pH to 6. The mixture was washed and freeze-dried. The mass ratio of chitosan-poly(lactic-co-hydroxyglycolic acid)-superoxide dismutase microcapsules to dopamine hydrochloride was 1:0.03, thus obtaining modified superoxide dismutase composite microspheres.

[0038] Example 3: The preparation method of modified cellulase includes the following steps:

[0039] Polyethylene glycol with a molecular weight of 6000 was dissolved in a citric acid-sodium citrate buffer solution with a pH of 4.8 to prepare a polyethylene glycol solution with a concentration of 10 g / L. The polyethylene glycol solution was then added to a cellulase solution with a mass ratio of polyethylene glycol to cellulase of 1:10. The enzyme activity of the cellulase solution was 10 U / mL (specific enzyme activity of 2000 U / g). The mixture was stirred for 0.5 h and then freeze-dried to obtain the modified cellulase.

[0040] Example 4 A compound enzyme preparation, prepared by the following method:

[0041] 20 parts by weight of xylanase with an enzyme activity of 25,000 U / g, 25 parts by weight of the modified cellulase prepared in Example 3, 15 parts by weight of glucanase with an enzyme activity of 4,500 U / g, 10 parts by weight of protease with an enzyme activity of 5,000 U / g, 12 parts by weight of amylase with an enzyme activity of 35,000 U / g, 8 parts by weight of pectinase with an enzyme activity of 4,200 U / g, 15 parts by weight of phytase with an enzyme activity of 20,000 U / g, and 25 parts by weight of the modified superoxide dismutase composite microspheres prepared in Example 1 were added to a mixer, mixed evenly, and then pressed to obtain a composite enzyme preparation.

[0042] Example 5 A complex enzyme preparation, prepared by the following method:

[0043] 20 parts by weight of xylanase with an enzyme activity of 25,000 U / g, 25 parts by weight of the modified cellulase prepared in Example 3, 15 parts by weight of glucanase with an enzyme activity of 4,500 U / g, 10 parts by weight of protease with an enzyme activity of 5,000 U / g, 12 parts by weight of amylase with an enzyme activity of 35,000 U / g, 8 parts by weight of pectinase with an enzyme activity of 4,200 U / g, 15 parts by weight of phytase with an enzyme activity of 20,000 U / g, and 25 parts by weight of the modified superoxide dismutase microspheres prepared in Example 2 were added to a mixer, mixed evenly, and then pressed to obtain a composite enzyme preparation.

[0044] Example 6 A complex enzyme preparation, prepared by the following method:

[0045] 25 parts by weight of xylanase with an enzyme activity of 25000 U / g, 20 parts by weight of modified cellulase prepared in Example 3, 15 parts by weight of dextranase with an enzyme activity of 4500 U / g, 10 parts by weight of protease with an enzyme activity of 5000 U / g, 12 parts by weight of amylase with an enzyme activity of 35000 U / g, 8 parts by weight of pectinase with an enzyme activity of 4200 U / g, 15 parts by weight of phytase with an enzyme activity of 20000 U / g, and 30 parts by weight of modified superoxide dismutase composite microspheres prepared in Example 1 were added to a mixer, mixed evenly, and then pressed to obtain a composite enzyme preparation.

[0046] Example 7 A complex enzyme preparation, prepared by the following method:

[0047] 25 parts by weight of xylanase with an enzyme activity of 25000 U / g, 20 parts by weight of modified cellulase prepared in Example 3, 15 parts by weight of dextranase with an enzyme activity of 4500 U / g, 10 parts by weight of protease with an enzyme activity of 5000 U / g, 12 parts by weight of amylase with an enzyme activity of 35000 U / g, 8 parts by weight of pectinase with an enzyme activity of 4200 U / g, 15 parts by weight of phytase with an enzyme activity of 20000 U / g, and 30 parts by weight of modified superoxide dismutase composite microspheres prepared in Example 2 were added to a mixer, mixed evenly, and then pressed to obtain a composite enzyme preparation.

[0048] Comparative Example 1: The preparation method of modified superoxide dismutase composite microspheres includes the following steps:

[0049] 80 mg of superoxide dismutase with an enzyme activity of 30,000 U / g was dissolved in phosphate buffer containing 1 wt% sodium alginate. The solution was then added to isooctane containing 6 wt% Span 80 at a volume ratio of 1:2. After high-speed homogenization for 3 min, Tween 80 was added dropwise and homogenized for another 3 min. Then, 8 wt% calcium chloride solution was added dropwise and homogenized for another 3 min. Finally, isopropanol was added and homogenized for another 3 min at the same speed. The solution was then centrifuged, washed, and freeze-dried to obtain the superoxide dismutase core layer.

[0050] The superoxide dismutase core layer was added to 0.5 wt% chitosan solution and incubated for 30 min. After centrifugation, the microcapsules were collected, washed once with the chitosan solution and then washed twice with water. After freeze-drying, chitosan-superoxide dismutase microcapsules were obtained.

[0051] The chitosan-superoxide dismutase microcapsules were added to a tris(hydroxymethyl)aminomethane hydrochloride buffer solution with a pH of 8.5, followed by the addition of a dopamine hydrochloride solution with a concentration of 2 mg / mL. The mixture was magnetically stirred at 300 r / min for 24 h, and then 0.1 mol / L hydrochloric acid solution was added to adjust the pH to 6. The mixture was washed and freeze-dried to obtain modified superoxide dismutase composite microspheres.

[0052] Comparative Example 2: The preparation method of modified superoxide dismutase composite microspheres includes the following steps:

[0053] 80 mg of superoxide dismutase with an enzyme activity of 30,000 U / g was dissolved in phosphate buffer containing 1 wt% sodium alginate. The solution was then added to isooctane containing 6 wt% Span 80 at a volume ratio of 1:2. After high-speed homogenization for 3 min, Tween 80 was added dropwise and homogenized for another 3 min. Then, 8 wt% calcium chloride solution was added dropwise and homogenized for another 3 min. Finally, isopropanol was added and homogenized for another 3 min at the same speed. The solution was then centrifuged, washed, and freeze-dried to obtain the superoxide dismutase core layer.

[0054] 400 mg of polylactic acid glycolic acid was dissolved in 10 mL of acetonitrile, and the superoxide dismutase core layer prepared above was added. After sonication at 100 W for 20 s, the mixture was added dropwise to peanut oil containing 6 wt% Span 80 while stirring at 600 r / min. The stirring speed was then increased to 1000 r / min and stirred for 2 min. Acetonitrile was removed by rotary evaporation under reduced pressure. The mixture was washed with petroleum ether and evaporated at 37 °C to obtain polylactic acid glycolic acid-superoxide dismutase microcapsules.

[0055] The polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules were added to 0.5 wt% chitosan solution and incubated for 30 min. After centrifugation, the microcapsules were collected, washed once with the chitosan solution and then twice with water. After freeze-drying, modified superoxide dismutase composite microspheres were obtained.

[0056] Compared with Example 4, Comparative Example 3 only replaced the modified superoxide dismutase composite microspheres prepared in Example 1 with the modified superoxide dismutase composite microspheres prepared in Comparative Example 1 by the same mass. The remaining components and preparation methods were completely the same as those in Example 4.

[0057] Compared with Example 4, Comparative Example 4 only replaced the modified superoxide dismutase composite microspheres prepared in Example 3 with the modified superoxide dismutase composite microspheres prepared in Comparative Example 2 by the same mass. The remaining components and preparation methods were completely the same as those in Example 4.

[0058] Compared with Example 4, Comparative Example 5 replaced the modified cellulase prepared in Example 3 with unmodified cellulase, while the remaining components and preparation methods were completely consistent with Example 4.

[0059] Compared with Example 4, Comparative Example 6 did not add the modified superoxide dismutase composite microspheres prepared in Example 1, but the remaining components and preparation methods were completely the same as in Example 4.

[0060] Performance testing

[0061] The Qingshan goats were provided by Henan Yuanmu Co., Ltd. A total of 200 healthy Qingshan goats were selected for the experiment, with an average weight of (16.18±0.13) kg. The feed for the Qingshan goats conformed to standard NY / T 816-2004, and the feed composition was 42% corn, 15% wheat bran, 12% soybean meal, 15% peanut cake, 13% alfalfa, 2% salt, and 1% of the compound enzyme preparations prepared in Examples 4-7 and Comparative Examples 3-6. A control group was set up without the compound enzyme preparation. The 200 Qingshan goats were randomly divided into 4 groups, with 5 replicates per group and 10 goats per replicate. The experiment lasted for 40 days. During the experiment, the Qingshan goats had free access to water and feed and were immunized according to the routine immunization program.

[0062] Growth performance test: On the day of the start and end of the experiment, the experimental sheep were fasted for 12 hours and their initial weight and final weight were measured on an empty stomach. The feed intake of each group of sheep during the experiment was recorded, and the average daily feed intake, average daily weight gain and feed conversion ratio of each group of sheep were calculated.

[0063] Average daily weight gain = (weight of sheep at the end of the experiment - weight of sheep at the beginning of the experiment) / number of days in the experiment

[0064] Average daily feed intake = Total feed intake / Number of days in the experiment

[0065] Feed conversion ratio = average daily feed intake / average daily weight gain; test results are shown in Table 1;

[0066] Apparent digestibility test of nutrients: For 3 days prior to the end of the experiment, fresh feces from sheep were collected daily, 100g each time, and 10mL of 10% nitrogen-fixing sulfate was added. The feces samples from the 3 days were mixed thoroughly, dried at 65℃, pulverized, and passed through a 40-mesh sieve for later use. 200g of each experimental diet was taken, pulverized, and passed through a 40-mesh sieve for later use. The apparent digestibility of crude protein, crude fat, dry matter, acid detergent fiber, and neutral detergent fiber in the diet and feces was determined and calculated using the hydrochloric acid insoluble ash content method.

[0067] Apparent digestibility of a certain nutrient = 100% - (nutrient content in feces × hydrochloric acid insoluble ash content in the diet) / (nutrient content in the diet × hydrochloric acid insoluble ash content in the feces) × 100%; the test results are shown in Table 1;

[0068] Table 1: Growth and digestibility data in Examples 4-7, Comparative Examples 3-6, and the control group

[0069]

[0070] Immunological marker testing: After the experiment, two sheep were randomly selected for each replicate. Blood was aseptically collected from the jugular vein and placed in a clean centrifuge tube. After standing for 15 minutes, the tube was centrifuged at 2000 rpm for 20 minutes. The supernatant serum was collected and stored at -20°C for later use. The levels of immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) were determined using an immunoglobulin ELISA kit (Shanghai Enzyme-Linked Biotechnology Co., Ltd.). After slaughter, the spleen of the sheep was removed, weighed, and used to calculate the spleen index.

[0071] Spleen index = Fresh spleen weight (g) / Sheep body weight (kg); Test results are shown in Table 2;

[0072] Meat quality testing: After the experiment, two sheep were randomly selected from each replicate for slaughter, and the longissimus dorsi muscle of the right side was harvested. Meat quality indicators were determined according to the experimental methods in the literature. The main parameters measured were the sheep's body weight, eye muscle area, shear force, cooking loss rate, drip loss rate, and meat color; the test results are shown in Table 2.

[0073] Table 2: Data on immune performance and meat quality in Examples 4-7, Comparative Examples 3-6, and the control group.

[0074]

[0075] As shown in Tables 1 and 2, the compound enzyme preparation prepared in this invention, when added to the diets of ruminants such as sheep, improves the apparent digestibility of various nutrients, thereby significantly enhancing their growth performance. Furthermore, the addition of modified superoxide dismutase (SOD) composite microspheres can improve the immunity and meat quality of Qingshan goats to a certain extent. In Comparative Example 3, the addition of modified SOD composite microspheres did not form a polylactic acid-hydroxyglycolic acid (PLGA) layer; in Comparative Example 4, the addition of modified SOD composite microspheres did not form a polydopamine layer. When the obtained compound enzyme preparations were used in the diets, the experimental sheep's ability to digest nutrients, growth performance, immunity indicators, and meat quality decreased. In Comparative Example 5, the added cellulase was not coated with polyvinyl alcohol, resulting in a significant decrease in the experimental sheep's ability to digest nutrients and growth performance. In Comparative Example 6, no modified SOD composite microspheres were added; when the obtained compound enzyme preparations were used in the diets, the immunity indicators and meat quality of the mutton decreased significantly.

[0076] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A compound enzyme preparation, characterized in that, It consists of the following components in parts by weight: Xylanase 10-30 parts, modified cellulase 15-35 parts, dextranase 8-20 parts, protease 5-15 parts, amylase 5-18 parts, pectinase 3-12 parts, phytase 5-25 parts, modified superoxide dismutase composite microspheres 15-40 parts. The modified cellulase is a polyethylene glycol-modified cellulase, and the modified superoxide dismutase composite microspheres are polydopamine-chitosan-polylactic acid-hydroxyglycolic acid-superoxide dismutase composite microspheres. The preparation method of the modified superoxide dismutase composite microspheres includes the following steps: A sodium alginate solution of superoxide dismutase was added to isooctane, followed by an emulsifier. After homogenization, calcium chloride solution and isoacetone were added to obtain the superoxide dismutase core layer. The superoxide dismutase core layer was added to an acetonitrile solution of polylactic acid-hydroxyglycolic acid, and then added to peanut oil to obtain polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules. The polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules were added to a chitosan solution and incubated to obtain chitosan-polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules. The chitosan-polylactic acid hydroxyglycolic acid-superoxide dismutase microcapsules were added to tris(hydroxymethyl)aminomethane hydrochloride buffer, and then dopamine hydrochloride was added to obtain modified superoxide dismutase composite microspheres. The mass ratio of the superoxide dismutase core layer to the polylactic acid-hydroxyglycolic acid is 1:5-7; The mass ratio of the polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules to the chitosan is 1:0.3-1.2; The mass ratio of the chitosan-polylactic acid-hydroxyglycolic acid-superoxide dismutase microcapsules to the dopamine hydrochloride is 1:0.01-0.05; The method for preparing the modified cellulase includes at least the following steps: A polyethylene glycol solution was added to a cellulase solution and dried to obtain modified cellulase. The degree of polymerization of the polyethylene glycol is 2000-8000, and the mass ratio of the polyethylene glycol to the cellulase is 1-20:

100.

2. A method for preparing the complex enzyme preparation as described in claim 1, characterized in that, The preparation steps include the following: Xylanase, modified cellulase, glucanase, protease, amylase, pectinase, phytase and modified superoxide dismutase composite microspheres are added to a mixer, mixed evenly and then pressed into shape to obtain a composite enzyme preparation.

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