Magnesium glycinate-containing feed capable of improving chitin of crustacean aquatic animals and resisting stress

Abstract

The invention relates to the technical field of feed additives, and provides a magnesium glycinate-containing feed capable of improving chitin of crustacean aquatic animals and resisting stress, and the magnesium glycinate-containing feed comprises the following raw materials by weight: 25-30% of fish meal; 18%-22% of soybean meal; 15%-20% of wheat flour; 0.15% to 0.45% of a magnesium glycinate chelate; 3%-5% of phospholipid oil; 1.2%-1.8% of a mineral premix; 0.6%-1.0% of a vitamin premix; the molecular formula of the magnesium glycinate chelate is Mg (C2H4NO2) 2. NH2O, n is equal to 0-4, an X-ray diffraction pattern of the magnesium glycinate chelate has characteristic peaks when 2theta is equal to 17.5 degrees + / -0.5 degrees, 24.3 degrees + / -0.5 degrees and 29.8 degrees + / -0.5 degrees, the chelation rate is larger than or equal to 95%, and the total molar ratio of calcium to magnesium is controlled to be 1: 0.8-1: 1.2. According to the technical scheme, the problems that in the anti-stress aspect of existing aquatic feed, an existing breeding mode is lagged in effect, poor in synergism and the like are solved; especially under stress conditions of salinity mutation, sudden drop of dissolved oxygen and the like, an existing feed is difficult to quickly adjust ion balance of crustacean, abnormal molting is easily caused, or the utilization rate of mineral substances is low, and eutrophication of a water body is aggravated.

Description

Technical Field

[0001] The present invention relates to the technical field of feed additives, and specifically, to a magnesium glycinate-containing feed for improving chitin and anti-stress of crustacean aquatic animals. Background Art

[0002] The chitin development and anti-stress ability of crustacean aquatic animals are key factors affecting aquaculture benefits; chitin, as the main component of the exoskeleton, requires a large amount of magnesium ions to participate in its synthesis process, and inorganic magnesium salts are generally used as a supplementary source in traditional feeds; however, the absorption and utilization rate of inorganic magnesium in animals is relatively low, usually <30%, and it is easy to combine with components such as phytic acid and cellulose in the feed to form insoluble complexes, resulting in low actual biological potency; research shows that the fluctuation of magnesium ion concentration in the aquaculture water directly affects the molting cycle of crustaceans. When the calcium-magnesium molar ratio is imbalanced, that is, Ca²⁺ / Mg²⁺ > 2.5, the soft-shell rate of crustacean aquatic animals will increase by 12% - 15%, and the survival rate will decrease by 8% - 10%; according to "Fisheries Science", in 2020, volume 39, the absorption rate of magnesium sulfate in Litopenaeus vannamei is only 28% - 32%, and the utilization rate decreases by 50% after binding with phytic acid; After retrieval, a natural feed additive for crustaceans and its preparation method with the authorized announcement number of CN102132776B. The additive described in this invention enhances the appetite of crustaceans, promotes their intestinal health and digestive function through the synergistic effect of each component in the pollution-free formulated feed; enables crustaceans to molt in time, while enhancing the immunity of crustaceans themselves, improving the survival rate, and accelerating their growth rate; However, in terms of anti-stress of existing aquatic feeds, in aquaculture practice, electrolytes or immune enhancers are often added temporarily, but there are problems such as lagging effects and poor synergy; especially under stress conditions such as sudden salinity changes and sudden drops in dissolved oxygen, existing feeds are difficult to quickly adjust the ion balance of crustaceans, often causing large-scale abnormal molting, or there is a lack of a linkage mechanism between feed feeding and the dynamic regulation of water ion concentration, resulting in low mineral utilization rate and aggravating water eutrophication. Therefore, we propose a magnesium glycinate-containing feed for improving chitin and anti-stress of crustacean aquatic animals. Summary of the Invention

[0003] The present invention provides a magnesium glycinate-containing feed for improving chitin and stress resistance of crustacean aquatic animals, which solves the problems in the prior art mentioned in the background art. In terms of stress resistance in existing aquatic feeds, in aquaculture practice, temporary addition of electrolytes or immune enhancers is often used, but there are problems such as lagging effects and poor synergy. Especially under stress conditions such as sudden changes in salinity and sudden drops in dissolved oxygen, existing feeds are difficult to quickly adjust the ion balance of crustaceans, often causing large-scale abnormal molting, or there is a lack of a linkage mechanism between feed feeding and dynamic regulation of water body ion concentration, resulting in low utilization rate of minerals and exacerbating water eutrophication.

[0004] The technical solution of the present invention is as follows: A magnesium glycinate-containing feed for improving chitin and stress resistance of crustacean aquatic animals, the raw material composition is by weight percentage: Fish meal 25% - 30%; Soybean meal 18% - 22%; Wheat flour 15% - 20%; Magnesium glycinate chelate 0.15% - 0.45%; Phospholipid oil 3% - 5%; Mineral premix 1.2% - 1.8%, the mineral premix includes calcium source, phosphorus source and zinc source; Vitamin premix 0.6% - 1.0%. The vitamin premix contains vitamin C, vitamin D 3 and vitamin E, and the content of vitamin C accounts for 30% - 50% of the premix; The magnesium glycinate chelate has the molecular formula Mg(C 2 H 4 NO 2 ) 2 ·nH 2 O, n = 0 - 4, its X-ray diffraction pattern has characteristic peaks at 2θ = 17.5° ± 0.5°, 24.3° ± 0.5°, 29.8° ± 0.5°, the chelation rate ≥ 95%, and the total molar ratio of calcium to magnesium is controlled at 1:0.8 - 1:1.2.

[0005] A preparation method of a magnesium glycinate-containing feed for improving chitin and stress resistance of crustacean aquatic animals includes the following steps: S1. Raw material pretreatment: Ultrafinely crush fish meal and soybean meal to a particle size ≤ 150 μm, and sieve wheat flour through 80 mesh for later use; S2. Premixing: Put fish meal, soybean meal, and wheat flour into a twin-shaft mixer according to the formula ratio, and mix at a speed of 200 r / min - 300 r / min for 15 min - 20 min; S3. Liquid addition: Heat phospholipid oil to 45°C - 50°C and then spray it into the mixing system, and at the same time add magnesium glycinate chelate; S4, Tempering treatment: Add water equivalent to 12% - 15% of the total weight of the mixed materials, introduce steam at 0.3MPa - 0.5MPa into the conditioner, control the material temperature at 75°C - 85°C, and the moisture content at 18% - 22%; S5, Extrusion granulation: Use a twin-screw extruder, with the die head temperature at 120°C - 135°C, the screw speed at 400r / min - 500r / min, and the die hole diameter at 2.0mm - 2.5mm for granulation; S6, Drying treatment: Three-stage gradient drying, drying at 90°C - 100°C for 15min - 20min in the first stage, drying at 70°C - 80°C for 30min - 40min in the second stage, and drying at 50°C - 60°C until the moisture content ≤ 10%; S7, Cooling and screening: Cool to room temperature with a countercurrent cooling tower, and remove particles with a particle size deviation > 0.2mm using a vibrating screen; S8, Post-spraying: Mix the vitamin premix and the mineral premix at a weight ratio of 1:1.8 - 1:2, coat with fat and then spray it onto the surface of the particles; S9, Packaging and storage: Nitrogen-filled packaging, control the oxygen content in the packaging bag ≤ 3%.

[0006] As a further technical solution of the present invention, in S1, the ultrafine grinding uses a jet mill, with the compressed air pressure at 0.7MPa - 0.9MPa and the classification wheel speed at 2500r / min - 3000r / min.

[0007] As a further technical solution of the present invention, in S4, the conditioner adopts a multi-layer disk structure, with the residence time of each layer controlled at 45s - 60s and the material stacking thickness at 7cm - 8cm.

[0008] As a further technical solution of the present invention, in S5, the screw compression ratio of the extruder is configured as 1:5 - 1:7, and the die head opening rate is 14% - 17%.

[0009] As a further technical solution of the present invention, in S6, the three-stage drying uses a through-flow dryer, with the hot air velocity at 1.2m / s - 1.5m / s and the relative humidity gradient set at 30%, 45%, and 60%.

[0010] As a further technical solution of the present invention, in S8, the fat coating uses a coating agent prepared by compounding palm oil and lecithin at a ratio of 5:1, with the spraying temperature at 55°C - 60°C and the atomization pressure at 0.15MPa - 0.2MPa.

[0011] As a further technical solution of the present invention, in S9, the nitrogen-filled packaging uses a double-chamber vacuum packaging machine, first evacuating to -0.08MPa and then filling with nitrogen to a positive pressure of 0.02MPa.

[0012] As a further technical solution of the present invention, the preparation method further includes a quality monitoring step: 1) After S4, sample and detect the mixing uniformity, and the coefficient of variation is required to be ≤5%; 2) After S7, detect the particle durability, and the pulverization rate is required to be ≤8%; 3) Detect the stability in water for the finished product, and the dissolution rate within 2h is required to be ≤12%.

[0013] As a further technical solution of the present invention, the parameters of the preparation system are automatically controlled by PLC. An on-line moisture detector and an infrared temperature sensor are set at key process points. Among them, the accuracy of the moisture detector is ±0.5%, and the accuracy of the infrared temperature sensor is ±1%, which is used to realize real-time data feedback adjustment.

[0014] The working principle and beneficial effects of the present invention are as follows: In the present invention, the magnesium absorption rate is improved: the absorption rate of magnesium glycinate chelate in the intestine of crustaceans is 2.3 times higher than that of traditional magnesium sulfate; the coating material can reduce the release rate of vitamin C in gastric juice to 15% / h, effectively maintaining the antioxidant capacity for up to 8h; the deposition rate of magnesium glycinate is increased from 45% of traditional feed to 78%, reducing the nitrogen and phosphorus load in water by 30% - 40%; magnesium glycinate activates the gene expression of chitin synthase, increasing the chitin content by 25%; the three-stage gradient drying technology enables the retention rate of vitamin premix to be ≥90%, and the pulverization rate of the shell is ≤8%, and the dissolution rate in water is ≤12%. Description of the Drawings

[0015] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0016] Figure 1 It is the preparation flow chart of the magnesium glycinate-containing feed for improving the chitin and anti-stress of crustacean aquaculture animals of the present invention. Specific Embodiments

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work fall within the scope of the present invention.

[0018] The preparation method of magnesium glycinate chelate is as follows: Mix glycine and magnesium oxide in a molar ratio of 2:1, react at pH 7.5 - 8.5 and a temperature of 60°C - 70°C for 2h, and obtain a product with a chelation rate ≥95% after spray drying; The chelation rate refers to the molar binding ratio of glycine to magnesium, which is determined by atomic absorption spectrometry. The calculation formula is: the actual amount of chelated magnesium / the theoretical amount of magnesium × 100%. Example 1

[0019] Please refer to Figure 1 , and the formula is as follows: fish meal 28%, soybean meal 20%, wheat flour 18%, magnesium glycine chelate 0.3%, where n = 2, phospholipid oil 4%, mineral premix 1.5%, vitamin premix 0.8%; The preparation parameters are as follows: The pressure of ultrafine grinding is 0.8 MPa, and the rotational speed of the classification wheel is 2800 r / min; The pressure of tempering steam is 0.4 MPa, and the material temperature is 80 °C; The temperature of the extrusion die head is 125 °C, and the screw compression ratio is 1:6; The humidity gradient of three-stage drying is 30% → 45% → 60%; The spraying temperature of the coating agent is 58 °C, and the atomization pressure is 0.18 MPa; In this example, the absorption rate of magnesium glycine is 78%, which is 2.4 times higher than that of Comparative Example 1 (magnesium sulfate) later; and in the salinity mutation experiment, the abnormal molting rate decreased from 18% to 5%; Under the condition that the dissolved oxygen drops suddenly from 4.2 mg / L to 2.5 mg / L, after feeding this feed for 2 hours, the concentration of magnesium ions in hemolymph rises from 0.8 mmol / L to 1.5 mmol / L, which is 3 times faster than that of the comparative example. Example 2

[0020] Please refer to Figure 1 , and the formula is as follows: fish meal 25%, soybean meal 22%, wheat flour 16%, magnesium glycine chelate 0.45%, where n = 0, phospholipid oil 3%, mineral premix 1.8%, vitamin premix 1.0%; The preparation parameters are as follows: The pressure of ultrafine grinding is 0.9 MPa, and the rotational speed of the classification wheel is 3000 r / min; The pressure of tempering steam is 0.5 MPa, and the material temperature is 85 °C; The temperature of the extrusion die head is 135 °C, and the screw compression ratio is 1:7; The humidity gradient of three-stage drying is 25% → 40% → 55%; The spraying temperature of the coating agent is 60 °C, and the atomization pressure is 0.2 MPa; Example 3

[0021] The formula is as follows: fish meal 30%, soybean meal 18%, wheat flour 20%, magnesium glycine chelate 0.15%, where n = 4, phospholipid oil 5%, mineral premix 1.2%, vitamin premix 0.6%; The preparation parameters are as follows: The pressure of ultrafine grinding is 0.7 MPa, and the rotational speed of the classification wheel is 2500 r / min; The pressure of tempering steam is 0.3 MPa, and the material temperature is 75 °C; The temperature of the extrusion die head is 120 °C, and the screw compression ratio is 1:5; The humidity gradient of three-stage drying is 35% → 50% → 65%; The spraying temperature of the coating agent is 55 °C, and the atomization pressure is 0.15 MPa. Example 4

[0022] Please refer to Figure 1 , and the formula is as follows: fish meal 27%, soybean meal 21%, wheat flour 17%, magnesium glycine chelate 0.25%, where n = 1, phospholipid oil 4.5%, mineral premix 1.6%, vitamin premix 0.9%; The preparation parameters are as follows: The pressure of ultrafine grinding is 0.75 MPa, and the rotational speed of the classification wheel is 2600 r / min; The pressure of tempering steam is 0.35 MPa, and the material temperature is 78 °C; The temperature of the extrusion die head is 130 °C, and the screw compression ratio is 1:6.5; The humidity gradient of three-stage drying is 28% → 42% → 58%; The spraying temperature of the coating agent is 57 °C, and the atomization pressure is 0.17 MPa. Example 5

[0023] The formula is as follows: fish meal 26%, soybean meal 19%, wheat flour 19%, magnesium glycine chelate 0.35%, where n = 3, phospholipid oil 3.5%, mineral premix 1.4%, vitamin premix 0.7%; The preparation parameters are as follows: The pressure of ultrafine grinding is 0.85 MPa, and the rotational speed of the classification wheel is 2900 r / min; The pressure of tempering steam is 0.45 MPa, and the material temperature is 82 °C; The temperature of the extrusion die head is 128 °C, and the screw compression ratio is 1:6.2; The humidity gradient of three-stage drying is 32% → 47% → 62%; The spraying temperature of the coating agent is 59 °C, and the atomization pressure is 0.19 MPa.

[0024] It should be noted that the formulas in Examples 1-5 are all by weight. On the basis of obtaining the corresponding data, the data obtained in each example are compared with the prior art and made into a table, as shown in the following table: Comparison item Defects of the prior art After improvement of the present invention Magnesium absorption efficiency Magnesium sulfate absorption rate: 32% Magnesium glycinate absorption rate: 78% Anti-stress response speed Takes effect 1 - 8 h after adding electrolyte The blood lymph magnesium concentration reaches the peak at 1.2 h Mineral deposition rate ≤45% 78% Abnormal molting rate (salinity mutation) 20% 5% Vitamin heat loss rate 40%～60% ≤10% Water ammonia nitrogen accumulation 0.5 mg / L - 0.8 mg / L 0.2 mg / L - 0.3 mg / L Comparative Example 1 The formula uses traditional inorganic magnesium feed, including 28% fish meal, 20% soybean meal, 18% wheat flour, 0.3% magnesium sulfate (converted to equimolar magnesium content), 4% phospholipid oil, 1.5% mineral premix, and 0.8% vitamin premix; The preparation method is as follows: Raw material pretreatment: Fish meal and soybean meal are commonly crushed to a particle size of ≤500 μm; Mixing: Mix in a single-shaft mixer at 150 r / min for 10 min; Conditioning: Directly add 10% cold water, steam pressure of 0.2 MPa, and temperature of 60 °C; Pelleting: Use a single-screw extruder, die head temperature of 150 °C, and screw speed of 300 r / min; Drying: Single-stage drying at 80 °C for 60 min; Packaging: Packed in ordinary woven bags without nitrogen filling.

[0025] On the basis of the above operations, the data of Comparative Example 1 and Example 1 will be compared and presented in a table as shown below: Comparison item Comparative example 1 Example 1 Magnesium absorption efficiency 32% 78% Time to peak of blood lymph magnesium 4.2h 1.2h Abnormal molting rate (salinity mutation) 18% 5% Retention rate of vitamin C 62% 92% Dissolution loss rate in water (2 h) 28% 10% Water ammonia nitrogen accumulation 0.7 mg / L 0.25 mg / L Through comparison, it can be found that Comparative Example 1 has the following defects: 1) Part of the magnesium sulfate decomposes into magnesium oxide during high-temperature extrusion at 150 °C, resulting in a decrease in biological utilization rate; 2) The unchelated magnesium ions combine with phytic acid in soybean meal to form insoluble precipitates, and the Mg 3 (PO 4 ) 2 characteristic peak is detected by XRD; 3) Single-stage drying leads to a heat loss rate of vitamin C as high as 38%.

[0026] Comparative Example 2 This comparative example uses a conventional coated anti-stress feed, with the weight formula percentage being: 28% fish meal, 20% soybean meal, 18% wheat flour, 0.3% glycine magnesium chelate, 4% phospholipid oil, 1.5% mineral premix, and 0.8% ordinary lipid-coated vitamin C The preparation method is as follows: Vitamin C coating: Single-layer hydrogenated palm oil coating, embedding rate of 65%; The specific mixing process is the same as that of Comparative Example 1, without PLC automatic control; The coated vitamin C is directly added after extrusion, without post-spraying and coating.

[0027] On the basis of the above operations, the data of Comparative Example 2 and Example 1 will be compared and presented in a table as shown below: Comparison item Comparative example 2 Example 1 Gastric juice sustained release rate of vitamin C 35% / h 15% / h Anti-stress response time (dissolved oxygen ≤ 4.2 mg / L) 6.5h 1.8h Increase amplitude of SOD enzyme activity 20% 55% Heat loss rate of coated vitamin C 48% 8% Granule pulverization rate 17% 6% Through comparison, it can be found that Comparative Example 2 has the following defects: 1) The ordinary lipid envelope disintegrates rapidly in gastric juice, and the release rate reaches 80% in 1 h when pH < 3; 2) Vitamin C is directly contacted with high-temperature expansion, resulting in a sharp increase in the loss rate due to the rupture of the envelope; 3) Without a linked calcium and magnesium regulation mechanism, the fluctuation of the Ca²⁺ / Mg²⁺ ratio in hemolymph reaches ±40% when the salinity mutates.

[0028] It should be noted that the feeding objects in the examples and comparative examples are the same batch of shrimps.

[0029] It should be noted that in the above examples or comparative examples, the coefficient of variation is detected according to GB / T 5918-2008 Determination Method for Feed Mixing Uniformity; the powdering rate is detected by the rotary box method, the rotation speed is 25 r / min, and the test time is 10 min.

[0030] In summary, the present invention has the following advantages over the prior art in application: 1. Ion balance rapid regulation mechanism: The magnesium absorption rate is improved. The absorption rate of magnesium glycine chelate with a chelation rate ≥ 95% in the intestine of crustaceans is 2.3 times higher than that of traditional magnesium sulfate; the optimized design of the calcium-magnesium molar ratio of 1:1 in the feed improves the blood lymph ion balance regulation speed by 40%.

[0031] 2. Anti-stress synergistic effect: Through the vitamin C sustained-release technology, the envelope material reduces the release rate of vitamin C in gastric juice to 15% / h, effectively maintaining the antioxidant capacity for up to 8 h; when the dissolved oxygen ≤ 4.2 mg / L, the addition amount of magnesium glycine is automatically increased to 0.6%, and the SOD enzyme activity in hemolymph is increased by 55%.

[0032] 3. High-efficiency utilization of minerals: By controlling water eutrophication, the deposition rate of magnesium glycine is increased from 45% of traditional feed to 78%, reducing the water body nitrogen and phosphorus load by 30% - 40%; at the same time, the Ca²⁺ / Mg²⁺ ratio (1.5 - 2.0) of the water body can be monitored in real time by PLC, and the feed feeding rate (0.8 - 1.2 g / kg·h) is automatically adjusted to avoid mineral waste.

[0033] 4. Promoting effect on chitin development: By accelerating chitin synthesis, magnesium glycine activates the expression of chitin synthase (CHS) gene, increasing the chitin content by 25%; the thickness of the dorsal carapace of the 4th abdominal segment increases by 12%, and the intermolt period is shortened from the conventional 18 days to 13 days.

[0034] 5. Process stability advantage: Through the protection of heat-sensitive components, the retention rate of vitamin premix is ≥ 90% by the three-stage gradient drying technology; and the powdering rate ≤ 8%, and the water loss rate ≤ 12%.

[0035] Through the combination of the core formula of magnesium glycinate chelate and the intelligent preparation process, this application systematically solves the problems of low mineral utilization efficiency, lagging stress response and water pollution in crustacean farming, and is significantly superior to the existing technology in terms of biological utilization efficiency, process stability and ecological benefits.

[0036] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans, characterized in that: The raw material composition is calculated by weight percentage: Fish meal 25%-30%; Soybean meal 18% to 22%; Wheat flour 15% to 20%; Magnesium glycinate chelate 0.15% to 0.45%; Lecithin oil 3% to 5%; Mineral premix 1.2% to 1.8%, the mineral premix includes calcium source, phosphorus source and zinc source; Vitamin premix 0.6%~1.0%. Vitamin premix contains vitamin C, vitamin D3 and vitamin E, and the vitamin C content accounts for 30%~50% of the premix; The molecular formula of the magnesium glycinate chelate is Mg(C2H4NO2)2·nH2O, n=0-4, and its X-ray diffraction spectrum has characteristic peaks at 2θ=17.5°±0.5°, 24.3°±0.5°, and 29.8°±0.5°, the chelation rate is ≥95%, and the total molar ratio of calcium to magnesium is controlled to be 1:0.8-1:1.

2.

2. A method for preparing a feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans, using the feed containing magnesium glycinate according to claim 1, characterized in that: The steps include: S1. Raw material pretreatment: ultrafinely grind fish meal and soybean meal to a particle size of ≤150μm, and sieve wheat flour through an 80-mesh sieve for later use; S2. Premixing: put fish meal, soybean meal and wheat flour into a double-shaft mixer according to the formula ratio, and mix at a speed of 200r / min-300r / min for 15min-20min; S3, liquid addition: heat the phospholipid oil to 45°C-50°C and spray it into the mixed system, and add magnesium glycinate chelate at the same time; S4, conditioning treatment: add water equivalent to 12% to 15% of the total weight of the mixed material, pass 0.3MPa-0.5MPa steam into the conditioner, control the material temperature at 75℃-85℃, and the moisture content at 18% to 22%; S5. Puffing and granulation: using a twin-screw extruder, die head temperature 120℃-135℃, screw speed 400r / min-500r / min, die hole diameter 2.0mm-2.5mm, granulation molding; S6. Drying treatment: three-stage gradient drying, the first stage is drying at 90℃-100℃ for 15min-20min, the second stage is drying at 70℃-80℃ for 30min-40min, and the third stage is drying at 50℃-60℃ until the moisture content is ≤10%; S7, cooling and screening: Use a countercurrent cooling tower to cool to room temperature, and use a vibrating screen to remove particles with a particle size deviation of >0.2mm; S8, post-spraying: the vitamin premix and the mineral premix are coated with fat in a weight ratio of 1:1.8-1:2 and then sprayed onto the particle surface; S9. Packaging and storage: Nitrogen-filled packaging, control the oxygen content in the packaging bag to ≤3%.

3. The method for preparing a feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans according to claim 2, characterized in that: The ultrafine grinding in S1 adopts a jet mill, the compressed air pressure is 0.7MPa-0.9MPa, and the rotating speed of the classifying wheel is 2500r / min-3000r / min.

4. The method for preparing a feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans according to claim 2, characterized in that: The conditioner in S4 adopts a multi-layer disc structure, the residence time of each layer is controlled to be 45s-60s, and the material stacking thickness is 7cm-8cm.

5. The method for preparing a feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans according to claim 2, characterized in that: The compression ratio of the screw of the extruder in the S5 is configured to be 1:5-1:7, and the die opening rate is 14% to 17%.

6. The method for preparing feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans according to claim 2, characterized in that: The three-stage drying in S6 adopts a through-flow dryer, the hot air speed is 1.2m / s-1.5m / s, and the relative humidity gradient is set to 30%, 45% and 60%.

7. The method for preparing feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans according to claim 2, characterized in that: The fat coating in S8 adopts a coating agent of palm oil and lecithin in a ratio of 5:1, the spraying temperature is 55°C-60°C, and the atomization pressure is 0.15MPa-0.2MPa.

8. The method for preparing feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans according to claim 2, characterized in that: The nitrogen-filled packaging in S9 adopts a double-chamber vacuum packaging machine, which is first evacuated to -0.08MPa and then filled with nitrogen to a positive pressure of 0.02MPa.

9. The method for preparing feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans according to claim 2, characterized in that: The preparation method also includes a quality monitoring step: 1) Take samples after S4 to test the mixing uniformity, and the coefficient of variation is required to be ≤5%; 2) After S7, the durability of the particles is tested, and the powdering rate is required to be ≤8%; 3) The finished product is tested for stability in water, and the 2h dissolution rate is required to be ≤12%.

10. The method for preparing feed containing magnesium glycinate for improving the chitin and stress resistance of crustaceans according to claim 2, characterized in that: The preparation system parameters are automatically controlled by PLC, and online moisture detectors and infrared temperature sensors are set at key process points. The accuracy of the moisture detector is ±0.5%, and the accuracy of the infrared temperature sensor is ±1%, which are used to achieve real-time data feedback adjustment.

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