Feed for promoting gonad development of sturgeons and preparation method thereof

Abstract

The invention discloses a feed for promoting gonad development of sturgeons and a preparation method of the feed. Comprising the following raw materials: 35-40 parts of fish meal, 13-17 parts of fermented soybean meal, 5-10 parts of chicken meal, 3-5 parts of corn protein powder, 7-12 parts of a compound additive, 4-8 parts of a plant extract, 5-8 parts of cuttlefish meal, 3-6 parts of euphausia superba meal, 3-5 parts of shell powder, 5-10 parts of fish oil, 3-5 parts of spirulina, 3-4 parts of microcrystalline cellulose, 1.5-2.5 parts of fumaric acid, 2-3 parts of soybean lecithin and 1.5-2 parts of monocalcium phosphate. And 0.8 to 1.1 parts of a compound premix. According to the feed, the sturgeons can obtain the most sufficient nutrition in the gonad development stage, so that gonad development is better promoted, the egg laying amount of the sturgeons can be increased, and the nutritional value and quality of eggs can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and particularly relates to a feed for promoting the development of sturgeon gonads and a preparation method thereof. Background Art

[0002] Sturgeons belong to the class Osteichthyes, the subclass Actinopterygii, the order Chondrocyma, and the order Acipenseriformes. They are the most primitive ray-finned bony fish in the world and are known as "living fossils". Sturgeons are large and have delicious meat. Their eggs can be made into precious caviar. Sturgeons not only have high academic research value, but also high economic value, and the breeding benefits are very considerable.

[0003] The greatest economic value of sturgeon lies in its caviar, which is known as "black soft gold". How to ensure that sturgeon gets the most adequate nutrition during the gonadal development stage, better promote the development of gonads, increase the egg yield and the content of rare golden fish eggs are issues that companies that use caviar as a terminal product urgently need to solve.

[0004] In recent years, with the gradual expansion of breeding scale, the reproductive performance of sturgeon broodstock has declined and the germplasm resources have degraded. The main manifestations are the reduced maturity of broodstock, the decreased induced spawning rate, fertilization rate, and hatching rate, the high deformity rate of fry, the large number of deaths before opening, and the low survival rate of seedlings. The reasons for this result are due to inbreeding on the one hand and the confusion of varieties caused by random hybridization on the other hand. Another very important reason is the long-term nutritional imbalance of sturgeon broodstock, so the breeding of sturgeon broodstock is particularly important and urgent. The broodstock stage is a special physiological stage of fish physiology, and its nutritional requirements are different from those of adult fish and fry. The nutrition of broodstock plays an important role in increasing the spawning amount, the quality of eggs and fry, and the growth and survival of fry. The quality of broodstock breeding and the breeding effect mainly depend on the broodstock breeding environment and the quality of compound feed, so optimizing broodstock feed helps to improve its reproductive performance.

[0005] The existing sturgeon feed has gradually developed from salmonid fish feed used in the early stage of breeding to sturgeon puffed granular feed and powdered feed. However, practice has shown that the existing sturgeon feed has too high fat composition, which easily leads to excessive fat content in the body of female sturgeon broodstock and the prominent phenomenon of "oil-encapsulated eggs", which seriously affects the reproductive performance of sturgeons such as spawning amount and egg quality, thereby affecting the quality of caviar of reserve sturgeons.

[0006] Chinese patent application CN109221644A discloses a high-fat content sturgeon compound feed and its preparation method, which includes the following components: 20-25 parts of fish meal, 14-18 parts of flour, 20-24 parts of soybean meal, 8-10 parts of soybean oil, 4-8 parts of pork meal, 2-4 parts of pig hemoglobin powder, 2-4 parts of fish oil, 1-3 parts of cuttlefish paste, 1-3 parts of calcium dihydrogen phosphate, 2-4 parts of bentonite, 0.2-0.5 parts of complex vitamins, 0.5-1 parts of complex minerals, 0.1-0.3 parts of lysine, 0.1-0.3 parts of methionine, 0.1-0.3 parts of choline chloride, 0.1-0.3 parts of betaine, and 0.2-0.4 parts of sodium chloride. The raw materials are crushed and ground, and the mixed raw materials are modulated in a feed modulator at 98°C for 3 minutes, and then granulated by a twin-screw extruder at 120°C, dried at 80°C, and cooled to prepare the sturgeon compound feed. The present invention reduces breeding costs and improves breeding benefits, and is a nutritious, healthy and environmentally friendly fish feed. However, the main purpose of the patent application is to use other raw material components with high nutritional value to replace fish meal, thereby reducing costs, and to meet the needs of sturgeon for feeding and rapid growth by adding high levels of fat. It is still unknown whether it has a promoting effect on the gonadal development and spawning of sturgeons.

[0007] Therefore, it is of great significance to develop a special feed for sturgeons that can help promote the development of sturgeon gonads and increase the amount of spawning in the art. Summary of the invention

[0008] In view of the deficiencies in the prior art, the object of the present invention is to provide a feed for promoting the gonadal development of sturgeons and a preparation method thereof, wherein the feed can provide the sturgeons with the most adequate nutrition during the gonadal development stage, thereby better promoting the development of the gonads, and can also increase the spawning amount of sturgeons, and improve the nutritional value and quality of eggs.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A nutritious feed for promoting the gonadal development of sturgeons, comprising the following raw materials by weight:

[0011] 35-40 parts of fish meal, 13-17 parts of fermented soybean meal, 5-10 parts of chicken meal, 3-5 parts of corn gluten meal, 7-12 parts of compound additives, 4-8 parts of plant extracts, 5-8 parts of squid meal, 3-6 parts of Antarctic krill meal, 3-5 parts of shell meal, 5-10 parts of fish oil, 3-5 parts of spirulina, 3-4 parts of microcrystalline cellulose, 1.5-2.5 parts of fumaric acid, 2-3 parts of soy lecithin, 1.5-2 parts of monocalcium phosphate, and 0.8-1.1 parts of compound premix.

[0012] In the present invention, fish meal is used as the main protein source, and fermented soybean meal, chicken meal, etc. are combined to provide comprehensive amino acid nutrition; special nutrition is provided by adding functional raw materials such as squid meal, Antarctic krill meal, spirulina, etc.; and functional components such as plant extracts and composite additives are added, which can effectively promote the development of sturgeon gonads and have good application value.

[0013] Preferably, a nutritious feed for promoting the gonadal development of sturgeons comprises the following raw materials by weight:

[0014] 36-38 parts of fish meal, 15-17 parts of fermented soybean meal, 7-9 parts of chicken meal, 4-5 parts of corn gluten meal, 9-11 parts of compound additives, 5-7 parts of plant extracts, 6-7 parts of squid meal, 4-5 parts of Antarctic krill meal, 4-5 parts of shell meal, 7-9 parts of fish oil, 4-5 parts of spirulina, 3-.5 parts of microcrystalline cellulose, 2-2.5 parts of fumaric acid, 2.5-3 parts of soy lecithin, 1.5-1.8 parts of monocalcium phosphate, and 0.9-1.1 parts of compound premix.

[0015] Preferably, the preparation method of the fermented soybean meal is as follows:

[0016] The soybean meal is crushed and sterilized at 115° C. for 30 minutes. After cooling, the composite bacterial powder is inoculated at a rate of 3-5%. Neutral protease, sterile water and molasses are added and stirred evenly, and then static culture and fermentation are carried out. After the fermentation is completed, the fermented soybean meal is dried, crushed and sieved to obtain the fermented soybean meal.

[0017] Fermented soybean meal is made from high-quality soybean meal using modern bioengineering bacteria fermentation technology and traditional Chinese solid fermentation technology. Microbial fermentation can eliminate anti-nutritional factors in soybean meal to the greatest extent possible, degrade macromolecular proteins in soybeans into high-quality small peptides, and produce active substances such as probiotics, amino acids, organic acids, vitamins and UGF (unknown growth factor).

[0018] In the present invention, a composite bacteria and enzyme synergistic fermentation method is adopted to prepare fermented soybean meal, and the composite bacteria composed of Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder is adopted, and neutral protease is added at the same time, so that the nutrition of soybean meal can be better improved and the growth inhibitory factor can be reduced. The bioactive small peptides contained in the fermented soybean meal not only do not compete with the amino acid absorption in the laying hen body, but also can promote the transport of free amino acids, improve protein utilization, and thus improve the quality of fish eggs.

[0019] Preferably, the composite bacterial powder is composed of Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:3-5:2-3, the added amount of the neutral protease is 3-5% of the mass of the soybean meal, the added amount of the sterile water is 40-50% of the mass of the soybean meal, the added amount of the molasses is 4-6% of the mass of the soybean meal, the fermentation temperature is 28-34°C, and the time is 60-72h.

[0020] Preferably, the preparation method of the plant extract is as follows:

[0021] The steps of mixing Leonurus japonicus, Fructus Ligustri Lucidi, Radix Rehmanniae Preparata, Folium Eucommiae and Codonopsis pilosula uniformly are freeze-ground to 20 meshes to obtain a mixed powder; then the mixed powder is added to an ethanol aqueous solution for leaching, filtered after the leaching is completed to obtain an extract, the extract is subjected to reduced pressure rotary evaporation to obtain a primary extract, and the filter residue is dried for later use; the filter residue is added to cyclohexane for ultrasonic-assisted extraction, filtered after the extraction is completed, and the filtrate is evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract are uniformly mixed to obtain the plant extract.

[0022] In the present invention, the chemical components in Leonurus japonicus are rich in variety, including alkaloids, flavonoids, diterpenes, triterpenes and other compounds. These chemical substances have the effects of anti-inflammatory, anti-oxidation, maintaining the reproductive function of the body, etc., and have high medicinal value.

[0023] Fructus Ligustri Lucidi contains numerous active ingredients, including triterpenes, flavonoids, cyclopentane ether terpenes, phenylethanol glycosides, polysaccharides, volatile oils, fatty acids, amino acids and various trace elements, etc. It has anti-inflammatory, antibacterial, anti-tumor, anti-osteoporosis, immunomodulatory, anti-aging, liver protection, blood sugar lowering, blood lipid lowering and antiviral effects.

[0024] Eucommia ulmoides contains rich chemical components, including terpenes, lignans, flavonoids, phenylpropanoids, polysaccharides, etc., which have significant effects in lowering blood sugar, blood pressure, blood lipids, anti-osteoporosis, anti-oxidation, immunomodulation, anti-inflammation, and antibacterial.

[0025] The chemical components contained in Codonopsis pilosula are very rich and complex. Its chemical components mainly include flavonoids, alkaloids, sugars, saponins, steroids, amino acids, etc. It has main pharmacological effects such as enhancing immune function, improving gastrointestinal function, anti-inflammatory, anti-tumor, improving learning and memory abilities, regulating the cardiovascular and cerebrovascular systems, and delaying aging.

[0026] The plant extract of the present invention is combined with a two-step method of ethanol aqueous solution extraction and cyclohexane ultrasonic extraction to achieve full extraction of effective components of different polarities; the ethanol aqueous solution mainly extracts water-soluble and alcohol-soluble active substances such as alkaloids and flavonoids in Leonurus japonicus, polysaccharides in Rehmannia glutinosa, and saponins in Ligustrum lucidum, while cyclohexane ultrasonic extraction can obtain fatty acids, sterols and fat-soluble active components in Chinese herbal medicine. These components work synergistically and have the effects of nourishing the kidney and blood, regulating endocrine, and promoting gonadal development. Among them, Leonurus japonicus can promote blood circulation and regulate menstruation, Ligustrum lucidum has the effect of nourishing the liver and kidney, Rehmannia glutinosa nourishes blood and yin, Eucommia ulmoides nourishes the liver and kidney, strengthens tendons and bones, and Codonopsis pilosula nourishes qi and strengthens the spleen, and together play the role of promoting the gonadal development of sturgeons. The extract obtained by the two-step extraction method retains the effective ingredients of various medicinal materials, improves bioavailability, and provides comprehensive nutritional support for the gonadal development of sturgeons.

[0027] Preferably, the mass ratio of the herb Leonurus japonicus, the fruit of Ligustrum lucidum, the root of Rehmannia glutinosa, the leaf of Eucommia ulmoides and the root of Codonopsis pilosula is 25-30:30-40:20-25:15-21:5-9, the volume fraction of ethanol in the ethanol aqueous solution is 50-60%, the solid-liquid ratio of the mixed powder to the ethanol aqueous solution is 1:15-20, the extraction temperature is 60-70°C, and the time is 0.5-1h; the solid-liquid ratio of the filter residue to cyclohexane is 1:10-15, the power of the ultrasound is 200-300W, the temperature of the ultrasonic-assisted extraction is 50-60°C, and the time is 60-90min.

[0028] Preferably, the preparation method of the composite additive is as follows:

[0029] The sepiolite is added into a sodium hydroxide solution for immersion treatment, and after the treatment is completed, it is filtered, washed, and dried to obtain a pretreated sepiolite; subsequently, the pretreated sepiolite is added into deionized water, and then magnesium nitrate, aluminum nitrate, hydroxypropyl-β-cyclodextrin, and urea are added, and after stirring evenly, a hydrothermal reaction is carried out, and after the reaction is completed, it is washed and dried to obtain a composite sepiolite; the composite sepiolite is added into a curcumin ethanol solution, immersed and adsorbed, and then filtered and dried to obtain the composite additive.

[0030] In the present invention, the added composite additive uses sepiolite as a base material, and its good porous structure enables it to have good adsorption capacity, and can effectively adsorb the fish oil in the formula. At the same time, magnesium-aluminum hydrotalcite is generated in situ on the sepiolite by a hydrothermal method to make its interior and surface complicated, and hydroxypropyl-β-cyclodextrin is added during the hydrothermal reaction to make it have an embedding function, thereby improving the adsorption and inclusion of fish oil. Finally, curcumin is loaded on the composite sepiolite. Curcumin has the function of preventing lipid oxidation in fish oil, and can also increase food intake, improve digestion and absorption of sturgeons, promote growth hormone secretion, regulate sex hormone levels, promote gonadal development of sturgeons, and increase spawning.

[0031] Preferably, the mass concentration of the sodium hydroxide solution is 4-7%, the temperature of the immersion treatment is 40-50°C, and the time is 1-2h; the mass ratio of the pretreated sepiolite, deionized water, magnesium nitrate, aluminum nitrate, hydroxypropyl-β-cyclodextrin, and urea is 70-80:1000:45-66:20-30:10-15:50-70, the temperature of the hydrothermal reaction is 110-115°C, and the time is 6-9h; the mass ratio of the composite sepiolite and the curcumin ethanol solution is 70-80:700-800, the concentration of curcumin in the curcumin ethanol solution is 5-8%, and the temperature of the immersion adsorption is 40-50°C, and the time is 1-2h.

[0032] Preferably, the composition of each kg of composite premix is:

[0033] Copper sulfate 2-3g, ferrous sulfate 10-15g, zinc sulfate 4-5g, manganese sulfate 50-100mg, magnesium sulfate 4-5g, potassium sulfate 5-8g, sodium chloride 6-8g, calcium iodate 1-2g, cobalt chloride 0.5-1.5g, sodium selenite 60-100mg, vitamin A 11000-14000IU, vitamin D 3000-4000IU, vitamin E 40-50mg, vitamin K32-3mg, vitamin B13-4mg, vitamin B210-12mg, niacin 30-40mg, riboflavin 50-70mg, pyridoxine 30-50mg, thiamine 25-35mg, calcium pantothenate 40-50mg, biotin 0.1-0.3mg, folic acid 20-30mg, vitamin B 12 50-60mg, ascorbic acid 0.5-1g, inositol 30-40mg, and the rest is zeolite powder.

[0034] The present invention also protects a method for preparing a nutritious feed for promoting the gonadal development of sturgeons as described above, comprising the following steps:

[0035] The raw materials are weighed according to the formula, the composite additives are mixed evenly with the shell powder, and then fish oil is added and stirred evenly, followed by the addition of fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix, and the mixture is mixed evenly to obtain a mixture, which is tempered at 110-120° C. for 4-6 minutes with water vapor, and then added to a granulator and granulated at 90-100° C. to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, followed by drying at 90° C., cooling, and sieving to obtain the nutritious feed.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The feed for promoting the gonadal development of sturgeon provided by the present invention uses fish meal as the main protein source, and is combined with fermented soybean meal, chicken meal, etc. to provide comprehensive amino acid nutrition. The added fish oil mainly provides fatty acids and energy, and plays an attractant role. The addition of lecithin can promote the normal development of gonads, thereby improving the gonadal development and improving the reproductive performance of sturgeons; the addition of spirulina can enhance the flavor of sturgeon and caviar, the addition of squid powder, Antarctic krill powder, spirulina and other functional raw materials provides special nutrition, and the addition of functional components such as plant extracts and composite additives can effectively promote the gonadal development of sturgeons, and has good application value.

[0038] (2) The feed for promoting the gonadal development of sturgeons provided by the present invention contains plant extracts, which are extracted from specific Chinese herbal medicines and proportions through a two-step method to extract the active ingredients therein. These ingredients work synergistically to have the effects of nourishing the kidney and blood, regulating endocrine, and promoting gonadal development. Among them, Leonurus japonicus can promote blood circulation and regulate menstruation, Ligustrum lucidum has the effect of nourishing the liver and kidneys, Rehmannia glutinosa can nourish blood and yin, Eucommia ulmoides can nourish the liver and kidneys and strengthen the tendons and bones, and Codonopsis pilosula can nourish qi and strengthen the spleen, and together they play the role of promoting the gonadal development of sturgeons.

[0039] (3) The feed for promoting gonadal development of sturgeons provided by the present invention can adsorb and encapsulate fish oil, thereby avoiding oxidation of fish oil during subsequent processing and storage, thereby causing the products of fat oxidation in the fish oil to damage sturgeon DNA and change the fluidity of cell membranes, thereby inducing diseases or even death; at the same time, the added curcumin also has anti-inflammatory, anti-fibrosis, antioxidant, neuroprotective and other effects, which can improve the growth performance and immunity of sturgeons. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In the present invention, the composition of each kg of composite premix is:

[0042] Copper sulfate 2.5g, ferrous sulfate 13g, zinc sulfate 4.5g, manganese sulfate 80mg, magnesium sulfate 4.5g, potassium sulfate 7g, sodium chloride 7g, calcium iodate 1.5g, cobalt chloride 1g, sodium selenite 80mg, vitamin A 13000IU, vitamin D 3500IU, vitamin E45mg, vitamin K32.5mg, vitamin B13.5mg, vitamin B211mg, niacin 35mg, riboflavin 60mg, pyridoxine 40mg, thiamine 30mg, calcium pantothenate 45mg, biotin 0.2mg, folic acid 25mg, vitamin B 12 55mg, ascorbic acid 0.8g, inositol 35mg, and the rest is zeolite powder.

[0043] The Bacillus licheniformis powder was purchased from Weifang Yihao Biotechnology Co., Ltd., with a live bacteria count of 10 billion cfu / g; the Lactobacillus reuteri powder was purchased from Guangdong Mingtong Biotechnology Co., Ltd., with a live bacteria count of 10 billion cfu / g; the Candida utilis powder was purchased from Shaanxi Angxu Biotechnology Co., Ltd., with a live bacteria count of 10 billion cfu / g; the neutral protease was purchased from Sichuan Huanxu Biotechnology Co., Ltd., with an enzyme activity of 50,000 U / g.

[0044] Example 1

[0045] A nutritious feed for promoting the gonadal development of sturgeons, comprising the following raw materials by weight:

[0046] 38 parts of fish meal, 15 parts of fermented soybean meal, 8 parts of chicken meal, 4 parts of corn gluten meal, 10 parts of compound additives, 6 parts of plant extracts, 7 parts of squid meal, 5 parts of Antarctic krill meal, 4 parts of shell meal, 8 parts of fish oil, 4 parts of spirulina, 3.5 parts of microcrystalline cellulose, 2 parts of fumaric acid, 2.5 parts of soybean lecithin, 1.8 parts of monocalcium phosphate, and 1 part of compound premix.

[0047] Wherein, the preparation method of the fermented soybean meal is as follows:

[0048] The soybean meal is crushed and sterilized at 115°C for 30 minutes. After cooling, composite bacterial powder (Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:4:3) is inoculated at 4% of the mass of the soybean meal, and neutral protease (4% of the mass of the soybean meal), sterile water (45% of the mass of the soybean meal) and molasses (5% of the mass of the soybean meal) are added and stirred evenly. The mixture is then placed at 32°C for fermentation for 66 hours. After fermentation is completed, the mixture is dried, crushed and sieved to obtain the fermented soybean meal.

[0049] The preparation method of the plant extract is as follows:

[0050] 28g of Leonurus japonicus, 35g of Ligustrum lucidum, 22g of Rehmannia glutinosa, 18g of Eucommia ulmoides leaves and 7g of Codonopsis pilosula were mixed evenly, and then crushed to 20 mesh at -40°C by freeze-crushing to obtain a mixed powder; the mixed powder was then added to an ethanol aqueous solution (the volume fraction of ethanol was 55%) at a solid-liquid ratio of 1:18, and extracted at 65°C for 1h. After the extraction was completed, the mixture was filtered to obtain an extract, and the extract was evaporated under reduced pressure to obtain a primary extract. The filter residue was dried and set aside; the filter residue was added to cyclohexane at a solid-liquid ratio of 1:13, and ultrasonic-assisted extraction was performed at a power of 250W and a temperature of 55°C for 80min. After the extraction was completed, the mixture was filtered, and the filtrate was evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract were mixed evenly to obtain the plant extract.

[0051] The preparation method of the composite additive is as follows:

[0052] The sepiolite is added into a sodium hydroxide solution with a mass concentration of 6%, and immersed at 45°C for 1.5 hours. After the treatment, it is filtered, washed and dried to obtain the pretreated sepiolite; then 75g of the pretreated sepiolite is added into 1000g of deionized water, followed by 60g of magnesium nitrate, 27g of aluminum nitrate, 13g of hydroxypropyl-β-cyclodextrin and 60g of urea, stirred evenly, and then hydrothermally reacted at 113°C for 7h. After the reaction is completed, it is washed and dried to obtain the composite sepiolite; 75g of the composite sepiolite is added into 750g of curcumin ethanol solution (the concentration of curcumin is 7%), immersed and adsorbed at 45°C for 1.5h, and then filtered and dried to obtain the composite additive.

[0053] A method for preparing a nutritious feed for promoting gonadal development of sturgeons comprises the following steps:

[0054] Weigh the raw materials according to the formula, mix the composite additive and shell powder evenly, add fish oil, stir evenly, then add fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix, mix evenly to obtain a mixture, condition it with water vapor at 115°C for 5 minutes, then add it to a granulator and granulate it at 95°C to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, then dry it at 90°C, cool it and sieve it to obtain the nutritious feed.

[0055] Example 2

[0056] A nutritious feed for promoting the gonadal development of sturgeons, comprising the following raw materials by weight:

[0057] 37 parts of fish meal, 16 parts of fermented soybean meal, 7 parts of chicken meal, 4 parts of corn gluten meal, 9 parts of composite additives, 6 parts of plant extract, 6 parts of squid meal, 5 parts of Antarctic krill meal, 4 parts of shell meal, 7 parts of fish oil, 4 parts of spirulina, 3.5 parts of microcrystalline cellulose, 2 parts of fumaric acid, 2.5 parts of soybean lecithin, 1.7 parts of monocalcium phosphate and 0.9 parts of composite premix.

[0058] Wherein, the preparation method of the fermented soybean meal is as follows:

[0059] The soybean meal is crushed and sterilized at 115°C for 30 minutes. After cooling, composite bacterial powder (Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:4:2) is inoculated at 4% of the mass of the soybean meal, and neutral protease (4% of the mass of the soybean meal), sterile water (45% of the mass of the soybean meal) and molasses (5% of the mass of the soybean meal) are added and stirred evenly. The mixture is then allowed to stand and ferment at 30°C for 70 hours. After the fermentation is completed, the mixture is dried, crushed and sieved to obtain the fermented soybean meal.

[0060] The preparation method of the plant extract is as follows:

[0061] 27g of Leonurus japonicus, 35g of Fructus Ligustri Lucidi, 23g of Radix Rehmanniae Preparata, 17g of Folium Eucommiae and 8g of Codonopsis pilosula were mixed evenly, and then the mixture was frozen and crushed to 20 mesh at -40°C to obtain a mixed powder; the mixed powder was then added to an ethanol aqueous solution (the volume fraction of ethanol was 55%) at a solid-liquid ratio of 1:17, and extracted at 65°C for 0.5h. After the extraction was completed, the mixture was filtered to obtain an extract, and the extract was evaporated under reduced pressure to obtain a primary extract. The filter residue was dried and set aside; the filter residue was added to cyclohexane at a solid-liquid ratio of 1:12, and ultrasonic-assisted extraction was performed at a power of 250W and a temperature of 55°C for 70min. After the extraction was completed, the mixture was filtered, and the filtrate was evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract were mixed evenly to obtain the plant extract.

[0062] The preparation method of the composite additive is as follows:

[0063] The sepiolite is added to a sodium hydroxide solution with a mass concentration of 5%, and immersed at 45°C for 1.5 hours. After the treatment, it is filtered, washed and dried to obtain a pretreated sepiolite; then 75g of the pretreated sepiolite is added to 1000g of deionized water, followed by 55g of magnesium nitrate, 23g of aluminum nitrate, 12g of hydroxypropyl-β-cyclodextrin, and 60g of urea. After stirring evenly, the mixture is hydrothermally reacted at 112°C for 8h. After the reaction is completed, it is washed and dried to obtain a composite sepiolite; 75g of the composite sepiolite is added to 750g of a curcumin ethanol solution (the concentration of curcumin is 6%), immersed and adsorbed at 45°C for 1.5h, and then filtered and dried to obtain the composite additive.

[0064] A method for preparing a nutritious feed for promoting gonadal development of sturgeons comprises the following steps:

[0065] Weigh the raw materials according to the formula, mix the composite additive and shell powder evenly, add fish oil, stir evenly, then add fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix, mix evenly to obtain a mixture, condition it with water vapor at 115°C for 5 minutes, then add it to a granulator and granulate it at 95°C to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, then dry it at 90°C, cool it and sieve it to obtain the nutritious feed.

[0066] Example 3

[0067] A nutritious feed for promoting the gonadal development of sturgeons, comprising the following raw materials by weight:

[0068] 35 parts of fish meal, 13 parts of fermented soybean meal, 5 parts of chicken meal, 3 parts of corn gluten meal, 7 parts of compound additives, 4 parts of plant extract, 5 parts of squid meal, 3 parts of Antarctic krill meal, 3 parts of shell meal, 5 parts of fish oil, 3 parts of spirulina, 3 parts of microcrystalline cellulose, 1.5 parts of fumaric acid, 2 parts of soybean lecithin, 1.5 parts of monocalcium phosphate, and 0.8 parts of compound premix.

[0069] Wherein, the preparation method of the fermented soybean meal is as follows:

[0070] The soybean meal is crushed and sterilized at 115°C for 30 minutes. After cooling, composite bacterial powder (Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:3:2) is added at an inoculation amount of 3-5% of the mass of the soybean meal, and neutral protease (3% of the mass of the soybean meal), sterile water (40% of the mass of the soybean meal) and molasses (4% of the mass of the soybean meal) are added and stirred evenly. The mixture is then allowed to stand and ferment at 28°C for 72 hours. After the fermentation is completed, the mixture is dried, crushed and sieved to obtain the fermented soybean meal.

[0071] The preparation method of the plant extract is as follows:

[0072] 25g of Leonurus japonicus, 30g of Fructus Ligustri Lucidi, 20g of Radix Rehmanniae Preparata, 15g of Folium Eucommiae and 5g of Codonopsis pilosula were mixed evenly, and then the mixture was frozen and crushed to 20 mesh at -30°C to obtain a mixed powder; the mixed powder was then added to an ethanol aqueous solution (the volume fraction of ethanol was 50%) at a solid-liquid ratio of 1:15, and extracted at 60°C for 1h. After the extraction was completed, the mixture was filtered to obtain an extract, and the extract was evaporated under reduced pressure to obtain a primary extract. The filter residue was dried and set aside; the filter residue was added to cyclohexane at a solid-liquid ratio of 1:10, and ultrasonic-assisted extraction was performed at a power of 200W and a temperature of 50°C for 90min. After the extraction was completed, the mixture was filtered, and the filtrate was evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract were mixed evenly to obtain the plant extract.

[0073] The preparation method of the composite additive is as follows:

[0074] The sepiolite is added into a sodium hydroxide solution with a mass concentration of 4%, and immersed at 40°C for 2 hours. After the treatment, it is filtered, washed and dried to obtain a pretreated sepiolite; then 70g of the pretreated sepiolite is added into 1000g of deionized water, followed by 45g of magnesium nitrate, 20g of aluminum nitrate, 10g of hydroxypropyl-β-cyclodextrin and 50g of urea, stirred evenly, and then hydrothermally reacted at 110°C for 9h. After the reaction is completed, it is washed and dried to obtain a composite sepiolite; 70g of the composite sepiolite is added into 700g of a curcumin ethanol solution (the concentration of curcumin is 8%), immersed and adsorbed at 40°C for 2h, and then filtered and dried to obtain the composite additive.

[0075] A method for preparing a nutritious feed for promoting gonadal development of sturgeons comprises the following steps:

[0076] Weigh the raw materials according to the formula, mix the composite additive and shell powder evenly, add fish oil, stir evenly, then add fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix, mix evenly to obtain a mixture, condition it with water vapor at 110°C for 6 minutes, then add it to a granulator and granulate it at 90°C to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, then dry it at 90°C, cool it and sieve it to obtain the nutritious feed.

[0077] Example 4

[0078] A nutritious feed for promoting the gonadal development of sturgeons, comprising the following raw materials by weight:

[0079] 40 parts of fish meal, 17 parts of fermented soybean meal, 10 parts of chicken meal, 5 parts of corn gluten meal, 12 parts of composite additives, 8 parts of plant extract, 8 parts of squid meal, 6 parts of Antarctic krill meal, 5 parts of shell meal, 10 parts of fish oil, 5 parts of spirulina, 4 parts of microcrystalline cellulose, 2.5 parts of fumaric acid, 3 parts of soybean lecithin, 2 parts of monocalcium phosphate, and 1.1 parts of composite premix.

[0080] Wherein, the preparation method of the fermented soybean meal is as follows:

[0081] The soybean meal is crushed and sterilized at 115°C for 30 minutes. After cooling, composite bacterial powder (Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:5:3) is inoculated at 5% of the mass of the soybean meal, and neutral protease (5% of the mass of the soybean meal), sterile water (50% of the mass of the soybean meal) and molasses (6% of the mass of the soybean meal) are added and stirred evenly. The mixture is then cultured and fermented at 34°C for 60 hours. After the fermentation is completed, the mixture is dried, crushed and sieved to obtain the fermented soybean meal.

[0082] The preparation method of the plant extract is as follows:

[0083] 30g of Leonurus japonicus, 40g of Fructus Ligustri Lucidi, 25g of Radix Rehmanniae Preparata, 21g of Folium Eucommiae and 9g of Codonopsis pilosula were mixed evenly, and then the mixture was frozen and crushed to 20 mesh at -50°C to obtain a mixed powder; the mixed powder was then added to an ethanol aqueous solution (the volume fraction of ethanol was 60%) at a solid-liquid ratio of 1:20, and extracted at 70°C for 0.5h. After the extraction was completed, the mixture was filtered to obtain an extract, and the extract was evaporated under reduced pressure to obtain a primary extract. The filter residue was dried and set aside; the filter residue was added to cyclohexane at a solid-liquid ratio of 1:15, and ultrasonic-assisted extraction was performed at a power of 300W and a temperature of 60°C for 60min. After the extraction was completed, the mixture was filtered, and the filtrate was evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract were mixed evenly to obtain the plant extract.

[0084] The preparation method of the composite additive is as follows:

[0085] The sepiolite is added into a sodium hydroxide solution with a mass concentration of 7%, and immersed at 50°C for 1 hour. After the treatment, it is filtered, washed and dried to obtain a pretreated sepiolite; then 80g of the pretreated sepiolite is added into 1000g of deionized water, followed by 66g of magnesium nitrate, 30g of aluminum nitrate, 15g of hydroxypropyl-β-cyclodextrin and 70g of urea, stirred evenly, and then hydrothermally reacted at 115°C for 6h. After the reaction is completed, it is washed and dried to obtain a composite sepiolite; 80g of the composite sepiolite is added into 800g of a curcumin ethanol solution (the concentration of curcumin is 5%), immersed and adsorbed at 50°C for 1h, and then filtered and dried to obtain the composite additive.

[0086] A method for preparing a nutritious feed for promoting gonadal development of sturgeons comprises the following steps:

[0087] The raw materials are weighed according to the formula, the composite additive and shell powder are mixed evenly, and then fish oil is added and stirred evenly, followed by the addition of fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix, and the mixture is mixed evenly to obtain a mixture, which is tempered at 120° C. for 4 min with water vapor, and then added to a granulator and granulated at 100° C. to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, followed by drying at 90° C., cooling, and sieving to obtain the nutritious feed.

[0088] Comparative Example 1

[0089] A nutritious feed for promoting the gonadal development of sturgeons, comprising the following raw materials by weight:

[0090] 38 parts of fish meal, 15 parts of fermented soybean meal, 8 parts of chicken meal, 4 parts of corn gluten meal, 10 parts of compound additives, 6 parts of plant extracts, 7 parts of squid meal, 5 parts of Antarctic krill meal, 4 parts of shell meal, 8 parts of fish oil, 4 parts of spirulina, 3.5 parts of microcrystalline cellulose, 2 parts of fumaric acid, 2.5 parts of soybean lecithin, 1.8 parts of monocalcium phosphate, and 1 part of compound premix.

[0091] Wherein, the preparation method of the fermented soybean meal is as follows:

[0092] The soybean meal is crushed and sterilized at 115°C for 30 minutes. After cooling, composite bacterial powder (Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:4:3) is inoculated at 4% of the mass of the soybean meal, and neutral protease (4% of the mass of the soybean meal), sterile water (45% of the mass of the soybean meal) and molasses (5% of the mass of the soybean meal) are added and stirred evenly. The mixture is then placed at 32°C for fermentation for 66 hours. After fermentation is completed, the mixture is dried, crushed and sieved to obtain the fermented soybean meal.

[0093] The preparation method of the plant extract is as follows:

[0094] 28g of Leonurus japonicus, 18g of Eucommia ulmoides leaves and 7g of Codonopsis pilosula were mixed evenly, and then the mixture was frozen and crushed to 20 mesh at -40°C to obtain a mixed powder; the mixed powder was then added to an ethanol aqueous solution (the volume fraction of ethanol was 55%) at a solid-liquid ratio of 1:18, and extracted at 65°C for 1h. After the extraction was completed, the mixture was filtered to obtain an extract, and the extract was evaporated under reduced pressure to obtain a primary extract. The filter residue was dried and set aside; the filter residue was added to cyclohexane at a solid-liquid ratio of 1:13, and ultrasonic-assisted extraction was performed at a power of 250W and a temperature of 55°C for 80min. After the extraction was completed, the mixture was filtered, and the filtrate was evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract were mixed evenly to obtain the plant extract.

[0095] The preparation method of the composite additive is as follows:

[0096] The sepiolite is added into a sodium hydroxide solution with a mass concentration of 6%, and immersed at 45°C for 1.5 hours. After the treatment, it is filtered, washed and dried to obtain the pretreated sepiolite; then 75g of the pretreated sepiolite is added into 1000g of deionized water, followed by 60g of magnesium nitrate, 27g of aluminum nitrate, 13g of hydroxypropyl-β-cyclodextrin and 60g of urea, stirred evenly, and then hydrothermally reacted at 113°C for 7h. After the reaction is completed, it is washed and dried to obtain the composite sepiolite; 75g of the composite sepiolite is added into 750g of curcumin ethanol solution (the concentration of curcumin is 7%), immersed and adsorbed at 45°C for 1.5h, and then filtered and dried to obtain the composite additive.

[0097] A method for preparing a nutritious feed for promoting gonadal development of sturgeons comprises the following steps:

[0098] Weigh the raw materials according to the formula, mix the composite additive and shell powder evenly, add fish oil, stir evenly, then add fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix, mix evenly to obtain a mixture, condition it with water vapor at 115°C for 5 minutes, then add it to a granulator and granulate it at 95°C to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, then dry it at 90°C, cool it and sieve it to obtain the nutritious feed.

[0099] Compared with Example 1, the plant extract of this comparative example does not contain Fructus Ligustri Lucidi and Radix Rehmanniae Preparata.

[0100] Comparative Example 2

[0101] A nutritious feed for promoting the gonadal development of sturgeons, comprising the following raw materials by weight:

[0102] 38 parts of fish meal, 15 parts of fermented soybean meal, 8 parts of chicken meal, 4 parts of corn gluten meal, 10 parts of compound additives, 6 parts of plant extracts, 7 parts of squid meal, 5 parts of Antarctic krill meal, 4 parts of shell meal, 8 parts of fish oil, 4 parts of spirulina, 3.5 parts of microcrystalline cellulose, 2 parts of fumaric acid, 2.5 parts of soybean lecithin, 1.8 parts of monocalcium phosphate, and 1 part of compound premix.

[0103] Wherein, the preparation method of the fermented soybean meal is as follows:

[0104] The soybean meal is crushed and sterilized at 115°C for 30 minutes. After cooling, composite bacterial powder (Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:4:3) is inoculated at 4% of the mass of the soybean meal, and neutral protease (4% of the mass of the soybean meal), sterile water (45% of the mass of the soybean meal) and molasses (5% of the mass of the soybean meal) are added and stirred evenly. The mixture is then placed at 32°C for fermentation for 66 hours. After fermentation is completed, the mixture is dried, crushed and sieved to obtain the fermented soybean meal.

[0105] The preparation method of the plant extract is as follows:

[0106] 28g of Leonurus japonicus, 35g of Ligustrum lucidum and 7g of Codonopsis pilosula were mixed evenly, and then the mixture was frozen and crushed to 20 mesh at -40°C to obtain a mixed powder; the mixed powder was then added to an ethanol aqueous solution (the volume fraction of ethanol was 55%) at a solid-liquid ratio of 1:18, and extracted at 65°C for 1h. After the extraction was completed, the mixture was filtered to obtain an extract, and the extract was evaporated under reduced pressure to obtain a primary extract. The filter residue was dried and set aside; the filter residue was added to cyclohexane at a solid-liquid ratio of 1:13, and ultrasonic-assisted extraction was performed at a power of 250W and a temperature of 55°C for 80min. After the extraction was completed, the mixture was filtered, and the filtrate was evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract were mixed evenly to obtain the plant extract.

[0107] The preparation method of the composite additive is as follows:

[0108] The sepiolite is added into a sodium hydroxide solution with a mass concentration of 6%, and immersed at 45°C for 1.5 hours. After the treatment, it is filtered, washed and dried to obtain the pretreated sepiolite; then 75g of the pretreated sepiolite is added into 1000g of deionized water, followed by 60g of magnesium nitrate, 27g of aluminum nitrate, 13g of hydroxypropyl-β-cyclodextrin and 60g of urea, stirred evenly, and then hydrothermally reacted at 113°C for 7h. After the reaction is completed, it is washed and dried to obtain the composite sepiolite; 75g of the composite sepiolite is added into 750g of curcumin ethanol solution (the concentration of curcumin is 7%), immersed and adsorbed at 45°C for 1.5h, and then filtered and dried to obtain the composite additive.

[0109] A method for preparing a nutritious feed for promoting gonadal development of sturgeons comprises the following steps:

[0110] Weigh the raw materials according to the formula, mix the composite additive and shell powder evenly, add fish oil, stir evenly, then add fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix, mix evenly to obtain a mixture, condition it with water vapor at 115°C for 5 minutes, then add it to a granulator and granulate it at 95°C to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, then dry it at 90°C, cool it and sieve it to obtain the nutritious feed.

[0111] Compared with Example 1, the plant extract of this comparative example does not contain Rehmannia glutinosa and Eucommia ulmoides leaves.

[0112] Comparative Example 3

[0113] A nutritious feed for promoting the gonadal development of sturgeons, comprising the following raw materials by weight:

[0114] 38 parts of fish meal, 15 parts of fermented soybean meal, 8 parts of chicken meal, 4 parts of corn gluten meal, 10 parts of pretreated sepiolite, 6 parts of plant extract, 7 parts of squid meal, 5 parts of Antarctic krill meal, 4 parts of shell meal, 8 parts of fish oil, 4 parts of spirulina, 3.5 parts of microcrystalline cellulose, 2 parts of fumaric acid, 2.5 parts of soybean lecithin, 1.8 parts of monocalcium phosphate and 1 part of composite premix.

[0115] Wherein, the preparation method of the fermented soybean meal is as follows:

[0116] The soybean meal is crushed and sterilized at 115°C for 30 minutes. After cooling, composite bacterial powder (Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:4:3) is inoculated at 4% of the mass of the soybean meal, and neutral protease (4% of the mass of the soybean meal), sterile water (45% of the mass of the soybean meal) and molasses (5% of the mass of the soybean meal) are added and stirred evenly. The mixture is then placed at 32°C for fermentation for 66 hours. After fermentation is completed, the mixture is dried, crushed and sieved to obtain the fermented soybean meal.

[0117] The preparation method of the plant extract is as follows:

[0118] 28g of Leonurus japonicus, 35g of Ligustrum lucidum, 22g of Rehmannia glutinosa, 18g of Eucommia ulmoides leaves and 7g of Codonopsis pilosula were mixed evenly, and then crushed to 20 mesh at -40°C by freeze-crushing to obtain a mixed powder; the mixed powder was then added to an ethanol aqueous solution (the volume fraction of ethanol was 55%) at a solid-liquid ratio of 1:18, and extracted at 65°C for 1h. After the extraction was completed, the mixture was filtered to obtain an extract, and the extract was evaporated under reduced pressure to obtain a primary extract. The filter residue was dried and set aside; the filter residue was added to cyclohexane at a solid-liquid ratio of 1:13, and ultrasonic-assisted extraction was performed at a power of 250W and a temperature of 55°C for 80min. After the extraction was completed, the mixture was filtered, and the filtrate was evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract were mixed evenly to obtain the plant extract.

[0119] The preparation method of the pretreated sepiolite is as follows:

[0120] The sepiolite was added into a sodium hydroxide solution with a mass concentration of 6%, and immersed at 45° C. for 1.5 hours. After the treatment, the solution was filtered, washed and dried to obtain the pretreated sepiolite.

[0121] A method for preparing a nutritious feed for promoting gonadal development of sturgeons comprises the following steps:

[0122] The raw materials are weighed according to the formula, the pretreated sepiolite and shell powder are mixed evenly, and then fish oil is added and stirred evenly, followed by fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix. The mixture is mixed evenly to obtain a mixture, which is tempered with water vapor at 115° C. for 5 min, then added to a granulator and granulated at 95° C. to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, followed by drying at 90° C., cooling and sieving to obtain the nutritious feed.

[0123] Compared with Example 1, the composite additive is replaced by pretreated sepiolite in this comparative example.

[0124] The female sturgeons of the same batch were raised, and the broodstock of Acipenser schrenckii from the same batch were selected, and the individuals with the same size, health and sexual maturity were selected as much as possible, and divided into 7 groups, each with 20 fish, and fed with the nutritious feeds of Examples 1-4 and Comparative Examples 1-3 respectively. The female sturgeons were first domesticated with commercial feed for 1 week, and after the feeding was normal, the 1-4 groups were fed with the nutritious feed prepared in Examples 1-4, and the 5-7 groups were fed with the nutritious feed prepared in Comparative Examples 1-3, for 12 months, and the feeding amount was 0.6% of the body weight every other day. The broodstock of Acipenser schrenckii were tested before and after feeding, and the results of the gonadal development level are shown in Table 1; after entering the breeding period, all eggs in the ovaries were taken out, and the number of eggs in the gonads of the sturgeons was counted with an automatic fish egg counter, and caviar was further processed to obtain 50g per portion, and 20cell fish eggs were weighed per portion to calculate the average single egg weight. The test data are shown in Table 1.

[0125] Table 1

[0126]

[0127]

[0128] As can be seen from Table 1 above, the nutritious feeds prepared in Examples 1-4 of the present invention can increase the egg-bearing capacity and egg quality of sturgeon gonads, promote the development of sturgeon gonads, and have good application prospects.

[0129] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A nutritious feed for promoting gonadal development of sturgeons, characterized in that: By weight, it includes the following raw materials: 35-40 parts of fish meal, 13-17 parts of fermented soybean meal, 5-10 parts of chicken meal, 3-5 parts of corn gluten meal, 7-12 parts of compound additives, 4-8 parts of plant extracts, 5-8 parts of squid meal, 3-6 parts of Antarctic krill meal, 3-5 parts of shell meal, 5-10 parts of fish oil, 3-5 parts of spirulina, 3-4 parts of microcrystalline cellulose, 1.5-2.5 parts of fumaric acid, 2-3 parts of soy lecithin, 1.5-2 parts of monocalcium phosphate, and 0.8-1.1 parts of compound premix.

2. The nutritious feed for promoting gonadal development of sturgeons according to claim 1, characterized in that: By weight, it includes the following raw materials: 36-38 parts of fish meal, 15-17 parts of fermented soybean meal, 7-9 parts of chicken meal, 4-5 parts of corn gluten meal, 9-11 parts of compound additives, 5-7 parts of plant extracts, 6-7 parts of squid meal, 4-5 parts of Antarctic krill meal, 4-5 parts of shell meal, 7-9 parts of fish oil, 4-5 parts of spirulina, 3-.5 parts of microcrystalline cellulose, 2-2.5 parts of fumaric acid, 2.5-3 parts of soy lecithin, 1.5-1.8 parts of monocalcium phosphate, and 0.9-1.1 parts of compound premix.

3. The nutritious feed for promoting gonadal development of sturgeons according to claim 1, characterized in that: The preparation method of the fermented soybean meal is as follows: The soybean meal is crushed and sterilized at 115° C. for 30 minutes. After cooling, the composite bacterial powder is inoculated at a rate of 3-5%. Neutral protease, sterile water and molasses are added and stirred evenly, and then static culture and fermentation are carried out. After the fermentation is completed, the fermented soybean meal is dried, crushed and sieved to obtain the fermented soybean meal.

4. The nutritious feed for promoting gonadal development of sturgeons according to claim 3, characterized in that: The composite bacterial powder is composed of Bacillus licheniformis powder, Lactobacillus reuteri powder and Candida utilis powder in a mass ratio of 10:3-5:2-3, the added amount of the neutral protease is 3-5% of the mass of the soybean meal, the added amount of the sterile water is 40-50% of the mass of the soybean meal, the added amount of the molasses is 4-6% of the mass of the soybean meal, the fermentation temperature is 28-34°C, and the time is 60-72h.

5. The nutritious feed for promoting gonadal development of sturgeons according to claim 1, characterized in that: The preparation method of the plant extract is as follows: The steps of mixing Leonurus japonicus, Fructus Ligustri Lucidi, Radix Rehmanniae Preparata, Folium Eucommiae and Codonopsis pilosula uniformly are freeze-ground to 20 meshes to obtain a mixed powder; then the mixed powder is added to an ethanol aqueous solution for leaching, filtered after the leaching is completed to obtain an extract, the extract is subjected to reduced pressure rotary evaporation to obtain a primary extract, and the filter residue is dried for later use; the filter residue is added to cyclohexane for ultrasonic-assisted extraction, filtered after the extraction is completed, and the filtrate is evaporated to remove cyclohexane to obtain a secondary extract; the primary extract and the secondary extract are uniformly mixed to obtain the plant extract.

6. The nutritious feed for promoting gonadal development of sturgeons according to claim 5, characterized in that: The mass ratio of the herb Leonurus japonicus, the fruit of Ligustrum lucidum, the root of Rehmannia glutinosa, the leaf of Eucommia ulmoides and the root of Codonopsis pilosula is 25-30:30-40:20-25:15-21:5-9, the volume fraction of ethanol in the ethanol aqueous solution is 50-60%, the solid-liquid ratio of the mixed powder to the ethanol aqueous solution is 1:15-20, the extraction temperature is 60-70°C, and the time is 0.5-1h; the solid-liquid ratio of the filter residue to cyclohexane is 1:10-15, the power of the ultrasound is 200-300W, the temperature of the ultrasound-assisted extraction is 50-60°C, and the time is 60-90min.

7. The nutritious feed for promoting gonadal development of sturgeons according to claim 1, characterized in that: The preparation method of the composite additive is as follows: The sepiolite is added into a sodium hydroxide solution for immersion treatment, and after the treatment is completed, it is filtered, washed, and dried to obtain a pretreated sepiolite; subsequently, the pretreated sepiolite is added into deionized water, and then magnesium nitrate, aluminum nitrate, hydroxypropyl-β-cyclodextrin, and urea are added, and after stirring evenly, a hydrothermal reaction is carried out, and after the reaction is completed, it is washed and dried to obtain a composite sepiolite; the composite sepiolite is added into a curcumin ethanol solution, immersed and adsorbed, and then filtered and dried to obtain the composite additive.

8. The nutritious feed for promoting gonadal development of sturgeons according to claim 7, characterized in that: The mass concentration of the sodium hydroxide solution is 4-7%, the temperature of the immersion treatment is 40-50°C, and the time is 1-2h; the mass ratio of the pretreated sepiolite, deionized water, magnesium nitrate, aluminum nitrate, hydroxypropyl-β-cyclodextrin, and urea is 70-80:1000:45-66:20-30:10-15:50-70, the temperature of the hydrothermal reaction is 110-115°C, and the time is 6-9h; the mass ratio of the composite sepiolite and the curcumin ethanol solution is 70-80:700-800, the concentration of curcumin in the curcumin ethanol solution is 5-8%, the temperature of the immersion adsorption is 40-50°C, and the time is 1-2h.

9. The nutritious feed for promoting gonadal development of sturgeons according to claim 1, characterized in that: The composition of each kg of composite premix is: Copper sulfate 2-3g, ferrous sulfate 10-15g, zinc sulfate 4-5g, manganese sulfate 50-100mg, magnesium sulfate 4-5g, potassium sulfate 5-8g, sodium chloride 6-8g, calcium iodate 1-2g, cobalt chloride 0.5-1.5g, sodium selenite 60-100mg, vitamin A 11000-14000IU, vitamin D 3000-4000IU, vitamin E 40-50mg, vitamin K32-3mg, vitamin B13-4mg, vitamin B210-12mg, niacin 30-40mg, riboflavin 50-70mg, pyridoxine 30-50mg, thiamine 25-35mg, calcium pantothenate 40-50mg, biotin 0.1-0.3mg, folic acid 20-30mg, vitamin B 12 50-60mg, ascorbic acid 0.5-1g, inositol 30-40mg, and the rest is zeolite powder.

10. A method for preparing a nutritious feed for promoting gonadal development of sturgeons as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: The raw materials are weighed according to the formula, the composite additives are mixed evenly with the shell powder, and then fish oil is added and stirred evenly, followed by the addition of fish meal, fermented soybean meal, chicken meal, corn protein meal, plant extract, squid meal, Antarctic krill meal, spirulina, microcrystalline cellulose, fumaric acid, soybean lecithin, calcium dihydrogen phosphate, and composite premix, and the mixture is mixed evenly to obtain a mixture, which is tempered at 110-120° C. for 4-6 minutes with water vapor, and then added to a granulator and granulated at 90-100° C. to obtain a granular feed with a diameter of 12 mm and a length of 15 mm, followed by drying at 90° C., cooling, and sieving to obtain the nutritious feed.

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