Tilapia mossambica feed additive as well as preparation method and application thereof

Abstract

The invention relates to the technical field of aquaculture, and discloses a tilapia mossambica feed additive as well as a preparation method and application thereof. The tilapia mossambica feed additive comprises the following raw materials in parts by mass: 20-30 parts of puffed rice bran, 10-20 parts of a traditional Chinese medicine extract, 15-25 parts of an anti-freezing active component, 5-15 parts of a supplementary component and 30-50 parts of water. The tilapia mossambica feed additive provided by the invention can significantly improve the survival rate of tilapia mossambica in a low-temperature environment; the tilapia mossambica feed additive provided by the invention can reduce the stress level of tilapia mossambica, improve the oxidation resistance of tilapia mossambica, reduce the lipid peroxidation degree of tilapia mossambica and reduce cell damage of tilapia mossambica.

Description

Technical Field

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

[0002] Tilapia has the advantages of fast growth, high yield, strong adaptability, etc., and is widely cultured globally. However, tilapia belongs to tropical and subtropical fish, and has poor cold tolerance. When the water temperature drops to a certain extent, its growth, physiological functions, and survival rate will be severely affected.

[0003] In order to improve the cold tolerance of tilapia, those skilled in the art have taken various methods. For example, improving the cold tolerance of tilapia by breeding cold-tolerant varieties, but this method has a long cycle, high cost, and limited effect. In addition, improving the aquaculture environment is also a common method, but this method will increase the aquaculture cost and is difficult to be widely applied in large-scale aquaculture.

[0004] As a convenient and effective means, feed additives have great potential in improving the stress resistance of aquatic animals. Therefore, developing a feed additive that can effectively enhance the cold tolerance of tilapia has important practical significance and market value. Summary of the Invention

[0005] The purpose of the present invention is to provide a tilapia feed additive, a preparation method thereof, and an application thereof. The tilapia feed additive can effectively improve the cold tolerance of tilapia.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A tilapia feed additive, comprising the following raw materials in parts by mass:

[0009] 20 - 30 parts of expanded rice bran, 10 - 20 parts of Chinese herbal medicine extract, 15 - 25 parts of antifreeze active ingredient, 5 - 15 parts of supplementary ingredient, and 30 - 50 parts of water.

[0010] Further, the preparation method of the expanded rice bran comprises the following steps:

[0011] 1) Mix rice bran, a mixed enzyme preparation, and water, and perform enzymatic hydrolysis to obtain enzymatically hydrolyzed rice bran;

[0012] 2) Perform microwave treatment on the enzymatically hydrolyzed rice bran obtained in step 1) to obtain microwave-pretreated rice bran;

[0013] 3) Perform gradient expansion on the microwave-pretreated rice bran obtained in step 2) to obtain the expanded rice bran.

[0014] Furthermore, in step 1), the mixed enzyme preparation is composed of β-glucanase, xylanase and cellulase mixed in a mass ratio of 2:3:1.

[0015] Furthermore, in step 1), the mass ratio of the rice bran, the mixed enzyme preparation and water is 10:1:4.

[0016] Furthermore, in step 1), the enzymatic hydrolysis is specifically: enzymatic hydrolysis at 45 °C for 2-3 h.

[0017] Furthermore, in step 2), the power of the microwave treatment is 300 W and the time is 2 min.

[0018] Furthermore, in step 3), the parameters of the gradient puffing are: 110 °C, 1.0 MPa, 2 min; 170 °C, 1.4 MPa, 1 min.

[0019] Further, the preparation method of the traditional Chinese medicine extract includes the following steps:

[0020] 1) Mix astragalus membranaceus, codonopsis pilosula, angelica sinensis and poria cocos, grind, and sieve to obtain a mixed traditional Chinese medicine powder;

[0021] 2) Place the mixed traditional Chinese medicine powder obtained in step 1) in water, decoct, concentrate, and dry to obtain the traditional Chinese medicine extract.

[0022] Furthermore, in step 1), the mass ratio of astragalus membranaceus, codonopsis pilosula, angelica sinensis and poria cocos is (2-4):(1-3):(1-3):(0.5-1.5).

[0023] Furthermore, in step 2), the mass-to-volume ratio of the mixed traditional Chinese medicine powder and water is 1 g:10 mL.

[0024] Furthermore, in step 2), the decocting is specifically: decocting at 80-100 °C for 3-5 h.

[0025] Further, the antifreeze active ingredient is composed of Antarctic krill powder, holly leaf extract and betaine mixed in a mass ratio of (8-12):(4-6):(0.5-1.5).

[0026] Further, the preparation method of the supplementary ingredient includes the following steps:

[0027] 1) Mix curcumin, astaxanthin, chitosan oligosaccharide, L-carnitine and adenosine monophosphate to obtain a supplementary ingredient precursor;

[0028] 2) Place gelatin and arabic gum in deionized water at 60 °C, adjust the pH = 4 to obtain a wall material solution;

[0029] 3) Place the precursor of the supplementary component obtained in step 1) into the wall material solution obtained in step 2), and perform ultrasonic treatment to obtain a supplementary component emulsion;

[0030] 4) Control the liquid layer thickness ≤ 1 cm, pour the supplementary component emulsion obtained in step 3) into a mold, and perform ultra-low temperature freezing to obtain a frozen supplementary component;

[0031] 5) Perform freeze-drying on the frozen supplementary component obtained in step 4) to obtain the supplementary component.

[0032] Furthermore, in step 1), the mass ratio of curcumin, astaxanthin, chitosan oligosaccharide, L-carnitine and adenosine monophosphate is (4 - 6)∶(2 - 4)∶(8 - 12)∶(1 - 3)∶(0.5 - 1.5).

[0033] Furthermore, in step 2), the mass ratio of gelatin and gum arabic is 1∶1.

[0034] Furthermore, in step 2), the concentration of the wall material solution is 10% (w / v).

[0035] Furthermore, in step 3), the power of the ultrasonic treatment is 200 W, the time is 2 min, and the temperature is 25 °C.

[0036] Furthermore, in step 4), the ultra-low temperature freezing specifically is: perform ultra-low temperature freezing at -80 °C for 2 h.

[0037] Furthermore, in step 5), the parameters of the freeze-drying are: -20 °C, 0.1 mbar, 24 h; 25 °C, 0.01 mbar, 6 h.

[0038] The second technical solution of the present invention:

[0039] The preparation method of the above-mentioned tilapia feed additive includes the following steps:

[0040] 1) Place the traditional Chinese medicine extract, antifreeze active ingredient and supplementary component into water, and perform ultrasonic dispersion to obtain an active ingredient dispersion liquid;

[0041] 2) Add expanded rice bran to the active ingredient dispersion liquid obtained in step 1), let it stand, perform ultrasonic treatment, and spray-dry to obtain the tilapia feed additive.

[0042] Further, in step 2), the standing time is 10 - 20 min.

[0043] Further, in step 2), the parameters of the ultrasonic treatment are: power density 2 W / cm 2 , pulse ratio 1∶2, duration 10 - 20 min.

[0044] Further, in step 2), the parameters of the spray drying are as follows: inlet air temperature 160°C, outlet air temperature 70°C, feed rate 5 mL / min, and rotation speed 15,000 rpm.

[0045] Further, in step 2), before the spray drying, maltodextrin with a mass fraction of 2% needs to be added.

[0046] The third technical solution of the present invention:

[0047] The application of the above-mentioned tilapia feed additive in enhancing the feed for tilapia's low-temperature tolerance.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] A tilapia feed additive provided by the present invention can significantly improve the survival rate of tilapia in a low-temperature environment, and the low-temperature survival rate can reach 92.1%.

[0050] A tilapia feed additive provided by the present invention can reduce the stress level of tilapia, improve the antioxidant capacity of tilapia, reduce the degree of lipid peroxidation of tilapia, and reduce cell damage of tilapia. Specific embodiments

[0051] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0052] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0053] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0054] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the specification of the present invention, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0055] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0056] In the following examples, the raw materials used are all commercially available. To ensure the comparability of the technical effects of the following examples and comparative examples, the raw materials used in the present invention are all from the same manufacturer and the same batch.

[0057] In the following examples, a preparation method of a tilapia feed additive includes the following steps:

[0058] 1. Preparation of expanded rice bran

[0059] 1) Mix β-glucanase, xylanase and cellulase according to the mass ratio of 2:3:1 to obtain a mixed enzyme preparation;

[0060] 2) Mix rice bran, the mixed enzyme preparation obtained in step 1) and water according to the mass ratio of 10:1:4, enzymatically hydrolyze at 45°C for 2 - 3 h to obtain enzymatically hydrolyzed rice bran;

[0061] 3) Carry out microwave treatment on the enzymatically hydrolyzed rice bran obtained in step 2) with a power of 300 W and a time of 2 min to obtain microwave-pretreated rice bran;

[0062] 4) Carry out gradient expansion on the microwave-pretreated rice bran obtained in step 3) to obtain the expanded rice bran;

[0063] Among them, the parameters of gradient expansion are: 110°C, 1.0 MPa, 2 min; 170°C, 1.4 MPa, 1 min;

[0064] 2. Preparation of traditional Chinese medicine extract

[0065] 1) Mix astragalus membranaceus, codonopsis pilosula, angelica sinensis and poria cocos according to the mass ratio of (2 - 4):(1 - 3):(1 - 3):(0.5 - 1.5), grind, and pass through an 80-mesh sieve to obtain a mixed traditional Chinese medicine powder;

[0066] 2) Place the mixed traditional Chinese medicine powder obtained in step 1) in water according to the mass-volume ratio of 1 g:10 mL, decoct at 80 - 100°C for 3 - 5 h, concentrate, and dry to obtain the traditional Chinese medicine extract;

[0067] 3. Preparation of Antifreeze Active Ingredient

[0068] Mix Antarctic krill powder, holly leaf extract and betaine according to the mass ratio of (8 - 12)∶(4 - 6)∶(0.5 - 1.5) to obtain the antifreeze active ingredient;

[0069] 4. Preparation of Supplementary Ingredient

[0070] 1) Mix curcumin, astaxanthin, chitosan oligosaccharide, L - carnitine and adenosine monophosphate according to the mass ratio of (4 - 6)∶(2 - 4)∶(8 - 12)∶(1 - 3)∶(0.5 - 1.5) to obtain a supplementary ingredient precursor;

[0071] 2) Place gelatin and gum arabic in deionized water at 60°C according to the mass ratio of 1∶1, and adjust the pH to 4 to obtain a wall material solution with a concentration of 10% (w / v);

[0072] 3) Place the supplementary ingredient precursor obtained in step 1) into the wall material solution obtained in step 2), control the power at 200W, the time at 2min, and the temperature at 25°C, and perform ultrasonic treatment on the mixed solution to obtain a supplementary ingredient emulsion;

[0073] 4) Control the liquid layer thickness ≤ 1cm, pour the supplementary ingredient emulsion obtained in step 3) into a mold, and then super - cool at - 80°C for 2h to obtain a frozen supplementary ingredient;

[0074] 5) Perform freeze - drying on the frozen supplementary ingredient obtained in step 4) to obtain the supplementary ingredient;

[0075] Among them, the parameters of freeze - drying are: - 20°C, 0.1mbar, 24h; 25°C, 0.01mbar, 6h;

[0076] 5. Preparation of Tilapia Feed Additive

[0077] 1) Weigh each raw material according to the following parts by mass:

[0078] Extruded rice bran 20 - 30 parts, traditional Chinese medicine extract 10 - 20 parts, antifreeze active ingredient 15 - 25 parts, supplementary ingredient 5 - 15 parts, water 30 - 50 parts;

[0079] 2) Place the traditional Chinese medicine extract, antifreeze active ingredient and supplementary ingredient weighed in step 1) into water and disperse them ultrasonically to obtain an active ingredient dispersion;

[0080] 3) Add the expanded rice bran weighed in step 1) to the active ingredient dispersion obtained in step 2). After standing for 10 - 20 min, control the power density to be 2 W / cm 2 , the pulse ratio is 1:2, and ultrasonically treat for 10 - 20 min. Then add maltodextrin with a mass fraction of 2% to the active ingredient dispersion. Control the inlet air temperature to be 160 °C, the outlet air temperature to be 70 °C, the feeding rate to be 5 mL / min, and the rotation speed to be 15000 rpm. Spray-dry the active ingredient dispersion to obtain the tilapia feed additive.

[0081] Example 1

[0082] A tilapia feed additive

[0083] 1. Preparation of expanded rice bran

[0084] 1) Mix β-glucanase, xylanase and cellulase according to the mass ratio of 2:3:1 to obtain a mixed enzyme preparation;

[0085] 2) Mix rice bran, the mixed enzyme preparation obtained in step 1) and water according to the mass ratio of 10:1:4, and enzymatically hydrolyze at 45 °C for 2 h to obtain enzymatically hydrolyzed rice bran;

[0086] 3) Control the power to be 300 W and the time to be 2 min, and perform microwave treatment on the enzymatically hydrolyzed rice bran obtained in step 2) to obtain microwave-pretreated rice bran;

[0087] 4) Perform gradient expansion on the microwave-pretreated rice bran obtained in step 3) to obtain the expanded rice bran;

[0088] Among them, the parameters of gradient expansion are: 110 °C, 1.0 MPa, 2 min; 170 °C, 1.4 MPa, 1 min;

[0089] 2. Preparation of traditional Chinese medicine extract

[0090] 1) Mix astragalus membranaceus, codonopsis pilosula, angelica sinensis and poria cocos according to the mass ratio of 2:1:1:0.5, grind, and pass through an 80-mesh sieve to obtain a mixed traditional Chinese medicine powder;

[0091] 2) Place the mixed traditional Chinese medicine powder obtained in step 1) in water according to the mass-volume ratio of 1 g:10 mL, decoct at 80 °C for 3 h, concentrate, and dry to obtain the traditional Chinese medicine extract;

[0092] 3. Preparation of antifreeze active ingredient

[0093] Mix Antarctic krill powder, holly leaf extract and betaine in a mass ratio of 8:4:0.5 to obtain the antifreeze active ingredient;

[0094] 4. Preparation of supplementary ingredient

[0095] 1) Mix curcumin, astaxanthin, chitosan oligosaccharide, L-carnitine and adenosine monophosphate in a mass ratio of 4:2:8:1:0.5 to obtain a supplementary ingredient precursor;

[0096] 2) Place gelatin and arabic gum in deionized water at 60 °C in a mass ratio of 1:1, and adjust the pH to 4 to obtain a wall material solution with a concentration of 10% (w / v);

[0097] 3) Place the supplementary ingredient precursor obtained in step 1) in the wall material solution obtained in step 2), control the power at 200 W, the time at 2 min, and the temperature at 25 °C, and perform ultrasonic treatment on the mixed solution to obtain a supplementary ingredient emulsion;

[0098] 4) Control the liquid layer thickness at 1 cm, pour the supplementary ingredient emulsion obtained in step 3) into a mold, and then supercool at -80 °C for 2 h to obtain a frozen supplementary ingredient;

[0099] 5) Freeze-dry the frozen supplementary ingredient obtained in step 4) to obtain the supplementary ingredient;

[0100] Among them, the parameters of freeze-drying are: -20 °C, 0.1 mbar, 24 h; 25 °C, 0.01 mbar, 6 h;

[0101] 5. Preparation of tilapia feed additive

[0102] 1) Weigh each raw material according to the following parts by mass:

[0103] 20 parts of expanded rice bran, 10 parts of traditional Chinese medicine extract, 15 parts of antifreeze active ingredient, 5 parts of supplementary ingredient, 30 parts of water;

[0104] 2) Place the traditional Chinese medicine extract, antifreeze active ingredient and supplementary ingredient weighed in step 1) in water and disperse them ultrasonically to obtain an active ingredient dispersion;

[0105] 3) Add the expanded rice bran weighed in step 1) to the active ingredient dispersion obtained in step 2), let it stand for 10 min, and then control the power density at 2 W / cm 2, with a pulse ratio of 1:2, ultrasonic treatment for 10 min, then adding maltodextrin with a mass fraction of 2% to the active ingredient dispersion, controlling the inlet air temperature at 160 °C, the outlet air temperature at 70 °C, the feeding rate at 5 mL / min, and the rotation speed at 15,000 rpm, and performing spray drying on the active ingredient dispersion to obtain the tilapia feed additive.

[0106] Example 2

[0107] A tilapia feed additive

[0108] 1. Preparation of expanded rice bran

[0109] 1) Mix β-glucanase, xylanase and cellulase according to the mass ratio of 2:3:1 to obtain a mixed enzyme preparation.

[0110] 2) Mix rice bran, the mixed enzyme preparation obtained in step 1) and water according to the mass ratio of 10:1:4, and enzymatically hydrolyze at 45 °C for 2.5 h to obtain enzymatically hydrolyzed rice bran.

[0111] 3) Control the power at 300 W and the time at 2 min, and perform microwave treatment on the enzymatically hydrolyzed rice bran obtained in step 2) to obtain microwave-pretreated rice bran.

[0112] 4) Perform gradient expansion on the microwave-pretreated rice bran obtained in step 3) to obtain the expanded rice bran.

[0113] Among them, the parameters of gradient expansion are: 110 °C, 1.0 MPa, 2 min; 170 °C, 1.4 MPa, 1 min.

[0114] 2. Preparation of traditional Chinese medicine extract

[0115] 1) Mix astragalus root, codonopsis pilosula, angelica sinensis and poria cocos according to the mass ratio of 3:2:2:1, grind, and pass through an 80-mesh sieve to obtain a mixed traditional Chinese medicine powder.

[0116] 2) Place the mixed traditional Chinese medicine powder obtained in step 1) in water according to the mass-volume ratio of 1 g:10 mL, decoct at 90 °C for 4 h, concentrate, and dry to obtain the traditional Chinese medicine extract.

[0117] 3. Preparation of antifreeze active ingredient

[0118] Mix Antarctic krill powder, holly leaf extract and betaine according to the mass ratio of 10:5:1 to obtain the antifreeze active ingredient.

[0119] 4. Preparation of supplementary ingredient

[0120] 1) Mix curcumin, astaxanthin, chitosan oligosaccharide, L-carnitine and adenosine monophosphate in a mass ratio of 5:3:10:2:1 to obtain a precursor of supplementary components.

[0121] 2) Place gelatin and gum arabic in deionized water at 60 °C according to a mass ratio of 1:1, and adjust the pH to 4 to obtain a wall material solution with a concentration of 10% (w / v).

[0122] 3) Place the precursor of supplementary components obtained in step 1) into the wall material solution obtained in step 2), control the power at 200 W, the time at 2 min, and the temperature at 25 °C, and perform ultrasonic treatment on the mixed solution to obtain a supplementary component emulsion.

[0123] 4) Control the liquid layer thickness at 1 cm, pour the supplementary component emulsion obtained in step 3) into a mold, and then ultra-low temperature freeze it at -80 °C for 2 h to obtain a frozen supplementary component.

[0124] 5) Perform freeze-drying on the frozen supplementary component obtained in step 4) to obtain the said supplementary component.

[0125] Among them, the parameters of freeze-drying are: -20 °C, 0.1 mbar, 24 h; 25 °C, 0.01 mbar, 6 h.

[0126] 5. Preparation of Tilapia Feed Additive

[0127] 1) Weigh each raw material according to the following parts by mass:

[0128] 25 parts of expanded rice bran, 15 parts of traditional Chinese medicine extract, 20 parts of antifreeze active ingredient, 10 parts of supplementary component, 40 parts of water;

[0129] 2) Place the traditional Chinese medicine extract, antifreeze active ingredient and supplementary component weighed in step 1) into water and disperse them ultrasonically to obtain an active ingredient dispersion.

[0130] 3) Add the expanded rice bran weighed in step 1) to the active ingredient dispersion obtained in step 2), let it stand for 15 min, then control the power density at 2 W / cm 2 , the pulse ratio at 1:2, ultrasonically treat for 15 min, then add maltodextrin with a mass fraction of 2% to the active ingredient dispersion, control the inlet air temperature at 160 °C, the outlet air temperature at 70 °C, the feeding rate at 5 mL / min, and the rotation speed at 15000 rpm, and perform spray drying on the active ingredient dispersion to obtain the said tilapia feed additive.

[0131] Example 3

[0132] A Tilapia Feed Additive

[0133] 1. Preparation of Expanded Rice Bran

[0134] 1) Mix β-glucanase, xylanase and cellulase according to the mass ratio of 2:3:1 to obtain a mixed enzyme preparation;

[0135] 2) Mix rice bran, the mixed enzyme preparation obtained in step 1) and water according to the mass ratio of 10:1:4, and enzymatically hydrolyze at 45 °C for 3 h to obtain enzymatically hydrolyzed rice bran;

[0136] 3) Perform microwave treatment on the enzymatically hydrolyzed rice bran obtained in step 2) with a power of 300 W for 2 min to obtain microwave-pretreated rice bran;

[0137] 4) Perform gradient expansion on the microwave-pretreated rice bran obtained in step 3) to obtain the expanded rice bran;

[0138] Among them, the parameters of gradient expansion are: 110 °C, 1.0 MPa, 2 min; 170 °C, 1.4 MPa, 1 min;

[0139] 2. Preparation of Traditional Chinese Medicine Extract

[0140] 1) Mix astragalus root, codonopsis pilosula, angelica sinensis and poria cocos according to the mass ratio of 4:3:3:1.5, grind, and pass through an 80-mesh sieve to obtain a mixed traditional Chinese medicine powder;

[0141] 2) Place the mixed traditional Chinese medicine powder obtained in step 1) in water according to the mass-volume ratio of 1 g:10 mL, decoct at 100 °C for 5 h, concentrate, and dry to obtain the traditional Chinese medicine extract;

[0142] 3. Preparation of Antifreeze Active Ingredient

[0143] Mix Antarctic krill powder, holly leaf extract and betaine according to the mass ratio of 12:6:1.5 to obtain the antifreeze active ingredient;

[0144] 4. Preparation of Supplementary Ingredient

[0145] 1) Mix curcumin, astaxanthin, chitosan oligosaccharide, L-carnitine and adenosine monophosphate according to the mass ratio of 6:4:12:3:1.5 to obtain a supplementary ingredient precursor;

[0146] 2) Place gelatin and arabic gum in deionized water at 60 °C according to the mass ratio of 1:1, and adjust the pH = 4 to obtain a wall material solution with a concentration of 10% (w / v);

[0147] 3) Place the precursor of the supplementary component obtained in step 1) into the wall material solution obtained in step 2), control the power at 200 W, the time at 2 min, and the temperature at 25 °C, and perform ultrasonic treatment on the mixed solution to obtain the supplementary component emulsion;

[0148] 4) Control the liquid layer thickness at 1 cm, pour the supplementary component emulsion obtained in step 3) into a mold, and then freeze it at -80 °C for 2 h to obtain the frozen supplementary component;

[0149] 5) Perform freeze-drying on the frozen supplementary component obtained in step 4) to obtain the said supplementary component;

[0150] Among them, the parameters of freeze-drying are: -20 °C, 0.1 mbar, 24 h; 25 °C, 0.01 mbar, 6 h;

[0151] 5. Preparation of tilapia feed additive

[0152] 1) Weigh each raw material according to the following parts by mass:

[0153] 30 parts of expanded rice bran, 20 parts of traditional Chinese medicine extract, 25 parts of antifreeze active ingredient, 15 parts of supplementary component, 50 parts of water;

[0154] 2) Place the traditional Chinese medicine extract, antifreeze active ingredient and supplementary component weighed in step 1) into water and disperse them ultrasonically to obtain the active ingredient dispersion;

[0155] 3) Add the expanded rice bran weighed in step 1) to the active ingredient dispersion obtained in step 2), let it stand for 20 min, then control the power density at 2 W / cm 2 , the pulse ratio at 1:2, perform ultrasonic treatment for 20 min, then add maltodextrin with a mass fraction of 2% to the active ingredient dispersion, control the inlet air temperature at 160 °C, the outlet air temperature at 70 °C, the feeding rate at 5 mL / min, and the rotation speed at 15000 rpm, and perform spray drying on the active ingredient dispersion to obtain the said tilapia feed additive.

[0156] Comparative Example 1

[0157] A tilapia feed additive

[0158] Same as Example 2, the difference is only that the preparation of expanded rice bran in step 1) is as follows:

[0159] 1) Control the power at 300 W and the time at 2 min, perform microwave treatment on rice bran to obtain microwave-pretreated rice bran;

[0160] 2) Perform gradient expansion on the microwave-pretreated rice bran obtained in step 1) to obtain the said expanded rice bran;

[0161] Among them, the parameters of gradient puffing are: 110 °C, 1.0 MPa, 2 min; 170 °C, 1.4 MPa, 1 min.

[0162] Comparative Example 2

[0163] A tilapia feed additive

[0164] Same as Example 2, the only difference is that the preparation of expanded rice bran in step 1 is as follows:

[0165] 1) Mix β-glucanase, xylanase and cellulase according to the mass ratio of 2:3:1 to obtain a mixed enzyme preparation;

[0166] 2) Mix rice bran, the mixed enzyme preparation obtained in step 1) and water according to the mass ratio of 10:1:4, and enzymatically hydrolyze at 45 °C for 2.5 h to obtain enzymatically hydrolyzed rice bran;

[0167] 3) Perform gradient puffing on the enzymatically hydrolyzed rice bran obtained in step 2) to obtain the expanded rice bran;

[0168] Among them, the parameters of gradient puffing are: 110 °C, 1.0 MPa, 2 min; 170 °C, 1.4 MPa, 1 min.

[0169] Comparative Example 3

[0170] A tilapia feed additive

[0171] Same as Example 2, the only difference is that the preparation of the antifreeze active ingredient in step 3 is as follows:

[0172] Mix holly leaf extract and betaine according to the mass ratio of 5:1 to obtain the antifreeze active ingredient.

[0173] Comparative Example 4

[0174] A tilapia feed additive

[0175] Same as Example 2, the only difference is that the preparation of the antifreeze active ingredient in step 3 is as follows:

[0176] Mix Antarctic krill meal and betaine according to the mass ratio of 10:1 to obtain the antifreeze active ingredient.

[0177] Comparative Example 5

[0178] A tilapia feed additive

[0179] Same as Example 2, the only difference is that the preparation of the antifreeze active ingredient in step 3 is as follows:

[0180] Mix Antarctic krill powder and Ilex leaf extract at a mass ratio of 10:5 to obtain the anti-freezing active ingredient.

[0181] Comparative Example 6

[0182] A tilapia feed additive

[0183] Same as Example 2, except that in the preparation of the supplementary component in step 4, step 1) is:

[0184] Mix astaxanthin, chitosan oligosaccharide, L-carnitine and adenosine monophosphate at a mass ratio of 3:10:2:1 to obtain a precursor of the supplementary component.

[0185] Comparative Example 7

[0186] A tilapia feed additive

[0187] Same as Example 2, except that in the preparation of the supplementary component in step 4, step 1) is:

[0188] Mix curcumin, chitosan oligosaccharide, L-carnitine and adenosine monophosphate at a mass ratio of 5:10:2:1 to obtain a precursor of the supplementary component.

[0189] Comparative Example 8

[0190] A tilapia feed additive

[0191] Same as Example 2, except that in the preparation of the supplementary component in step 4, step 1) is:

[0192] Mix curcumin, astaxanthin, L-carnitine and adenosine monophosphate at a mass ratio of 5:3:2:1 to obtain a precursor of the supplementary component.

[0193] Comparative Example 9

[0194] A tilapia feed additive

[0195] Same as Example 2, except that in the preparation of the supplementary component in step 4, step 1) is:

[0196] Mix curcumin, astaxanthin, chitosan oligosaccharide and adenosine monophosphate at a mass ratio of 5:3:10:1 to obtain a precursor of the supplementary component.

[0197] Comparative Example 10

[0198] A tilapia feed additive

[0199] Same as Example 2, the only difference is that in the preparation of the supplementary component in step 4, step 1) is as follows:

[0200] Mix curcumin, astaxanthin, chitosan oligosaccharide and L-carnitine according to the mass ratio of 5:3:10:2 to obtain a supplementary component precursor.

[0201] Comparative Example 11

[0202] A tilapia feed additive

[0203] Same as Example 2, the only difference is that the preparation of the supplementary component in step 4 is as follows:

[0204] Mix curcumin, astaxanthin, chitosan oligosaccharide, L-carnitine and adenosine monophosphate according to the mass ratio of 5:3:10:2:1 to obtain the said supplementary component.

[0205] Comparative Example 12

[0206] A tilapia feed additive

[0207] Same as Example 2, the only difference is that the preparation of the tilapia feed additive in step 5 is as follows:

[0208] 1) Weigh each raw material according to the following parts by mass:

[0209] 25 parts of expanded rice bran, 15 parts of Chinese medicine extract, 20 parts of antifreeze active ingredient, 10 parts of supplementary component, 40 parts of water;

[0210] 2) Mix the raw materials weighed in step 1) to obtain the said tilapia feed additive.

[0211] Effect verification:

[0212] Performance verification of the tilapia feed additive in enhancing low-temperature tolerance

[0213] 1. Experimental grouping

[0214] Select 800 tilapia with the same body weight (50±5g) and good health, and randomly divide them into 16 groups, with 50 tails in each group, namely the control group (fed with basal diet) and the experimental groups (fed with basal diet + tilapia feed additives prepared in Examples 1-3 or Comparative Examples 1-12)

[0215] 2. Feeding environment

[0216] The experiment was carried out in a temperature-controlled aquaculture system. The initial water temperature was maintained at 28±1°C, with an adaptation period of 7 days. Then, the temperature was gradually decreased at a rate of 2°C per day to 10°C and maintained at this temperature for the experiment. The experimental period was 4 weeks;

[0217] 3. Feed Feeding

[0218] Feed twice at fixed times every day (08:00 and 17:00), and the feeding amount is 5% of the fish body weight;

[0219] 4. Survival Rate Test

[0220] During the experiment, record the death situation of tilapia in each group every day, and calculate the survival rate;

[0221] Survival rate (%) = (initial number of fish - number of dead fish) / initial number of fish × 100%.

[0222] The calculation results of the survival rate are shown in Table 1:

[0223] Table 1 Calculation Results of Survival Rate

[0224]

[0225] It can be seen from the data in Table 1 that a tilapia feed additive provided by the present invention can significantly improve the survival rate of tilapia in a low-temperature environment, and the low-temperature survival rate can reach 92.1%.

[0226] 5. Serum Physiological Index Test

[0227] After the experiment, randomly select 10 fish from each group, collect blood from the caudal vein, centrifuge at 3000 rpm for 10 min to separate the serum; use a kit to detect the contents of cortisol (COR), superoxide dismutase (SOD), malondialdehyde (MDA) and lactate dehydrogenase (LDH) in the serum;

[0228] Among them, the COR content reflects the stress level of the fish body, the SOD activity reflects the antioxidant capacity, the MDA content can measure the degree of lipid peroxidation, and the LDH activity is related to the degree of cell damage;

[0229] The test results of the serum physiological indexes are shown in Table 2;

[0230] Table 2 Test Results of Serum Physiological Indexes

[0231]

[0232] It can be seen from the data in Table 2 that a tilapia feed additive provided by the present invention can reduce the stress level (COR content) of tilapia, improve the antioxidant capacity (SOD activity) of tilapia, reduce the degree of lipid peroxidation (MDA content) of tilapia, and reduce the cell damage (LDH activity) of tilapia.

[0233] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A tilapia feed additive, characterized in that, It comprises the following raw materials in parts by mass: 20 - 30 parts of expanded rice bran, 10 - 20 parts of traditional Chinese medicine extract, 15 - 25 parts of antifreeze active ingredient, 5 - 15 parts of supplementary ingredient, and 30 - 50 parts of water.

2. The tilapia feed additive according to claim 1, characterized in that, The preparation method of the expanded rice bran comprises the following steps: 1) Mix rice bran, mixed enzyme preparation and water, and carry out enzymatic hydrolysis to obtain enzymatically hydrolyzed rice bran; 2) Carry out microwave treatment on the enzymatically hydrolyzed rice bran obtained in step 1) to obtain microwave pretreated rice bran; 3) Carry out gradient expansion on the microwave pretreated rice bran obtained in step 2) to obtain the expanded rice bran.

3. According to claim 2, a tilapia feed additive, characterized in that In step 1), the mixed enzyme preparation is composed of β - glucanase, xylanase and cellulase mixed in a mass ratio of 2∶3∶1; In step 1), the mass ratio of the rice bran, mixed enzyme preparation and water is 10∶1∶4; In step 1), the enzymatic hydrolysis is specifically: carry out enzymatic hydrolysis at 45°C for 2 - 3 h; In step 2), the power of the microwave treatment is 300 W and the time is 2 min; In step 3), the parameters of the gradient expansion are: 110°C, 1.0 MPa, 2 min; 170°C, 1.4 MPa, 1 min.

4. The tilapia feed additive according to claim 1, characterized in that, The preparation method of the traditional Chinese medicine extract comprises the following steps: 1) Mix astragalus membranaceus, codonopsis pilosula, angelica sinensis and poria cocos, grind, and sieve to obtain mixed traditional Chinese medicine powder; 2) Place the mixed traditional Chinese medicine powder obtained in step 1) in water, decoct, concentrate, and dry to obtain the traditional Chinese medicine extract.

5. According to claim 4, a tilapia feed additive, characterized in that In step 1), the mass ratio of astragalus membranaceus, codonopsis pilosula, angelica sinensis and poria cocos is (2 - 4)∶(1 - 3)∶(1 - 3)∶(0.5 - 1.5); In step 2), the mass - to - volume ratio of the mixed traditional Chinese medicine powder and water is 1 g∶10 mL; In step 2), the decoction is specifically: decoct at 80 - 100°C for 3 - 5 h.

6. The tilapia feed additive according to claim 1, characterized in that, The antifreeze active ingredient is composed of Antarctic krill powder, Ilex purpurea extract and betaine mixed in a mass ratio of (8 - 12)∶(4 - 6)∶(0.5 - 1.5).

7. The tilapia feed additive according to claim 1, characterized in that, The preparation method of the supplementary ingredient comprises the following steps: 1) Mix curcumin, astaxanthin, chitosan oligosaccharide, L - carnitine and adenosine monophosphate to obtain a supplementary ingredient precursor; 2) Place gelatin and arabic gum in deionized water at 60°C, and adjust the pH = 4 to obtain a wall material solution; 3) Place the supplementary ingredient precursor obtained in step 1) in the wall material solution obtained in step 2), and carry out ultrasonic treatment to obtain a supplementary ingredient emulsion; 4) Control the liquid layer thickness ≤ 1 cm, pour the supplementary ingredient emulsion obtained in step 3) into a mold, and carry out ultra - low temperature freezing to obtain a frozen supplementary ingredient; 5) Carry out freeze - drying on the frozen supplementary ingredient obtained in step 4) to obtain the supplementary ingredient.

8. According to claim 7, a tilapia feed additive, characterized in that In step 1), the mass ratio of curcumin, astaxanthin, chitosan oligosaccharide, L - carnitine and adenosine monophosphate is (4 - 6)∶(2 - 4)∶(8 - 12)∶(1 - 3)∶(0.5 - 1.5); In step 2), the mass ratio of the gelatin to the gum arabic is 1:1; In step 2), the concentration of the wall material solution is 10% (w / v); In step 3), the power of the ultrasonic treatment is 200 W, the time is 2 min, and the temperature is 25 °C; In step 4), the ultra-low temperature freezing is specifically: ultra-low temperature freezing at -80 °C for 2 h; In step 5), the parameters of the freeze-drying are: -20 °C, 0.1 mbar, 24 h; 25 °C, 0.01 mbar, 6 h.

9. A preparation method of the tilapia feed additive according to any one of claims 1 to 8, characterized in that, It includes the following steps: 1) Place the traditional Chinese medicine extract, the antifreeze active ingredient and the supplementary ingredient in water, and ultrasonically disperse to obtain an active ingredient dispersion; 2) Add the expanded rice bran to the active ingredient dispersion obtained in step 1), let it stand, perform ultrasonic treatment, and spray dry to obtain the tilapia feed additive.

10. Use of a tilapia feed additive according to any one of claims 1 to 8 in a feed for enhancing the low-temperature tolerance of tilapia.

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