Functional feed for largemouth bass as well as preparation method and application of functional feed

Abstract

According to the functional feed for largemouth bass as well as the preparation method and the application of the functional feed, the components and the proportion in the feed are optimized, the caragana microphylla extract rich in terpenoids and organic acid esters is added, and experiments prove that the functional feed can promote growth and liver health of largemouth bass and maintain the steady state of an organism; the accumulated survival rate of the micropterus salmoides for resisting aeromonas hydrophila infection is increased, the survival rate and yield of the micropterus salmoides are further increased, green and healthy culture of the micropterus salmoides is achieved, and industrial development is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of aquatic feed and additives, in particular to a functional feed for largemouth bass and a preparation method and application thereof. Background Art

[0002] Largemouth bass (Micropterus salmoides) is a carnivorous warm-water fish. With the improvement of aquaculture technology, it has high economic value due to its fast growth rate, strong adaptability and plump meat. It is widely farmed in warm waters in central and southern my country. The demand for largemouth bass in the market mainly comes from high-end catering, leisure fishing and ornamental fish markets. Its meat is delicious and is loved by consumers. Due to the difficulty of aquaculture and market demand, the market price of largemouth bass is relatively high.

[0003] Disease prevention and control remains an important issue during the breeding process. Effective measures need to be taken to prevent and control the occurrence of diseases. Largemouth bass have high requirements for water quality. However, under intensive breeding, the high-density breeding model promotes largemouth bass susceptibility to bacterial diseases, parasitic diseases and fungal diseases. Among them, the economic losses caused by Aeromonas hydrophila to largemouth bass breeding are particularly prominent. In the early stages of Aeromonas hydrophila infection, the fish may show decreased appetite, changes in body color and skin ulcers. In the later stages, gill ulcers and white spots on the body surface and gills may appear. In severe infections, inflammation may occur inside the fish body, especially lesions in the liver, spleen and intestines, leading to weakness and death of the fish. However, there are few functional feeds on the market that are designed to improve the infection of Aeromonas hydrophila for largemouth bass.

[0004] Patent application CN202110575565.2 discloses a method for identifying immunogenic outer membrane proteins of Aeromonas hydrophila from largemouth bass, and CN202211491869.1 discloses a subunit nanovaccine of Aeromonas hydrophila and its preparation method and application. These patented inventions do not improve the survival rate of largemouth bass against Aeromonas hydrophila infection from the perspective of feeding nutrition. CN201110412129.X Caragana granular feed, this invention patent is only applicable to the breeding of poultry such as cattle and sheep, and is not applicable to the breeding of aquatic animals. Therefore, it is necessary to develop corresponding functional feeds that improve the survival rate of largemouth bass against Aeromonas hydrophila infection in a targeted manner to promote the healthy growth of farmed animals, and improve the survival rate and economic benefits. Summary of the invention

[0005] The purpose of the present invention is to provide a functional feed for largemouth bass and a preparation method and application thereof. The functional feed can promote the liver health of largemouth bass and improve its ability to resist Aeromonas hydrophila infection.

[0006] The technical solution of the present invention is as follows:

[0007] A functional feed for largemouth bass, comprising the following raw materials by weight:

[0008] 40-50 parts of Chilean fish meal, 2-8 parts of high-gluten flour, 2-8 parts of corn starch, 2-8 parts of corn gluten meal, 2-8 parts of soybean meal, 2-8 parts of brewer's yeast, 4-10 parts of chicken meal, 2-8 parts of fermented soybean meal, 2-10 parts of fine bran, 1 part of monocalcium phosphate, 1 part of composite premix, 0.02 parts of vitamin C, 0.5 parts of choline chloride, 1 part of lecithin, 5 parts of mixed fish oil, 0.8-6 parts of Caragana extract;

[0009] Wherein, per 1kg of functional feed, the above-mentioned composite premix is ​​composed of the following raw materials: vitamin B1 10-11mg, riboflavin 8-9mg, pyridoxine hydrochloride 10-11mg, vitamin B12 0.2-0.3mg, vitamin K3 10-11mg, inositol 100-110mg, calcium pantothenate 20-22mg, niacin 50-52mg, folic acid 2-3mg, biotin 2-3mg, vitamin A (500,000 IU) 400-420mg, vitamin D 5-6mg, vitamin E (500,000 IU) 100-120mg, ethoxyquin 150-160mg, sub-powder 0.13-0.14g, potassium chloride 200 -220mg, potassium iodide 60-65mg, cobalt sulfate 100-110mg, copper sulfate 24-26mg, ferrous sulfate 400-420mg, zinc sulfate 170-175mg, manganese sulfate 75-80mg, magnesium sulfate 800-820mg, sodium selenite 5-52mg, zeolite powder 3.0-3.5g;

[0010] The above-mentioned Caragana extract is obtained by extracting Caragana branches in water. The content of terpenoid compounds in the above-mentioned Caragana extract is greater than 4%, and the content of organic acid esters is greater than 5%.

[0011] In some possible implementations, the functional feed is composed of the following raw materials by weight:

[0012] 43-48 parts of Chilean fish meal, 3-6 parts of high-gluten flour, 2-5 parts of corn starch, 3-6 parts of corn gluten meal, 3-6 parts of soybean meal, 3-6 parts of brewer's yeast, 5-9 parts of chicken meal, 5-8 parts of fermented soybean meal, 5-10 parts of fine bran, 1 part of monocalcium phosphate, 1 part of composite premix, 0.02 parts of vitamin C, 0.5 parts of choline chloride, 1 part of lecithin, 5 parts of mixed fish oil, and 0.8-4 parts of Caragana extract.

[0013] In some possible implementations, the added amount of Caragana korshinskii extract is 0.8 parts.

[0014] A method for preparing the above functional feed comprises the following steps:

[0015] (1) crushing Chilean fish meal, high-gluten flour, corn starch, corn gluten meal, soybean meal, brewer's yeast, chicken meal, fermented soybean meal, fine bran and monocalcium phosphate, and then fully mixing to obtain a mixture A;

[0016] (2) The mixed material A, the composite premix, choline chloride, vitamin C and Caragana korshinskii extract are fully mixed, and then ultrafinely ground to obtain a mixed material B;

[0017] (3) fully mixing the mixture B, lecithin and 0-8 wt % of mixed fish oil, then adding water and mixing again to obtain a mixture C;

[0018] (4) The mixture C is subjected to conditioning treatment to prepare an expanded pellet feed, which is then dried and then vacuum-sprayed with the remaining mixed fish oil at 50-70° C. The mixture is cooled and sieved to obtain a functional feed.

[0019] In some possible implementations, the method for preparing the Caragana korshinskii extract comprises the following steps:

[0020] (1) Crush the branches of Caragana korshinskii, add water, and fully homogenize with the aid of a homogenizer to obtain a mixture D;

[0021] (2) extracting the mixture D in a water bath, filtering to remove the Caragana korshinskii branches, and then subjecting the mixture to rotary evaporation and spray drying to obtain a Caragana korshinskii extract;

[0022] The solid-liquid ratio of Caragana korshinskii branches to water is 1-4:2-10, the extraction temperature is 70-90°C, and the extraction time is 1-3h.

[0023] In some possible implementations, the solid-liquid ratio of Caragana korshinskii branches to water is 1-3:2-8, the extraction temperature is 75-90° C., and the extraction time is 2-3 h.

[0024] In some possible implementations, the solid-liquid ratio of Caragana korshinskii branches to water is 1-2:4-6, the extraction temperature is 80-90° C., and the extraction time is 2.5-3 h.

[0025] Application of the functional feed in resisting Aeromonas hydrophila infection of largemouth bass.

[0026] Application of the above functional feed in improving the immunity of largemouth bass.

[0027] Application of the functional feed in improving liver health of largemouth bass.

[0028] The present invention has at least the following beneficial effects:

[0029] The present invention provides a functional feed, in which components and proportions in the feed are optimized and a Caragana korshinskii extract rich in terpenoid compounds and organic acid esters is added. Experiments have confirmed that the functional feed can promote the growth of largemouth seabass, maintain liver health, maintain body homeostasis, and increase the cumulative survival rate of largemouth seabass against Aeromonas hydrophila infection, thereby increasing the survival rate and yield of largemouth seabass, realizing green and healthy breeding of largemouth seabass, and promoting the development of the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings will be briefly introduced below. Obviously, the accompanying drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0031] Figure 1 : This is a graph showing the effect of the feed provided by the present invention on the weight gain rate of largemouth bass. Each group of data is labeled with different letters. There is a significant difference between group a and group b (P<0.05), the same below;

[0032] Figure 2 This is a graph showing the effect of the functional feed provided by the present invention on the feeding rate of largemouth bass;

[0033] Figure 3 This is a graph showing the effect of the functional feed provided by the present invention on serum ALT of largemouth bass;

[0034] Figure 4 This is a graph showing the effect of the functional feed provided by the present invention on serum AST of largemouth bass;

[0035] Figure 5 This is a graph showing the effect of the functional feed provided by the present invention on T-AOC in the liver of largemouth bass;

[0036] Figure 6 This is a graph showing the effect of the functional feed provided by the present invention on T-SOD in the liver of largemouth bass;

[0037] Figure 7 This is a graph showing the effect of the functional feed provided by the present invention on CAT in the liver of largemouth bass;

[0038] Figure 8 This is a graph showing the effect of the functional feed provided by the present invention on MDA in the liver of largemouth bass;

[0039] Fig. 9 This is a diagram showing the effect of the functional feed provided by the present invention on the liver tissue structure of largemouth bass, with the black arrow pointing to the liver vacuoles;

[0040] Fig.10 This is a graph showing the effect of the functional feed provided by the present invention on serum C3 of largemouth bass;

[0041] Fig.11 This is a graph showing the effect of the functional feed provided by the present invention on serum IgM of largemouth bass;

[0042] Fig.12 The invention discloses an effect of the functional feed provided by the invention on the survival rate of largemouth bass in resisting infection with Aeromonas hydrophila. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. In the examples, those without specifying specific techniques or conditions are carried out according to the techniques or conditions described in the literature in this area or according to the product specification. Those without specifying the manufacturer of reagents or instruments used are all conventional products that can be obtained commercially. In the following examples, if not clearly stated, "%" refers to weight percentage.

[0044] In the following comparative examples and examples 1-3, the composition of the composite premix per 1 kg of functional feed is vitamin B110 mg, riboflavin 8 mg, pyridoxine hydrochloride 10 mg, vitamin B12 0.2 mg, vitamin K3 10 mg, inositol 100 mg, calcium pantothenate 20 mg, niacin 50 mg, folic acid 2 mg, biotin 2 mg, vitamin A (500,000 IU) 400 mg, vitamin D 5 mg, vitamin E (500,000 IU) 100 mg, ethoxyquin 150 mg, secondary powder 0.1328 g, potassium chloride 200 mg, potassium iodide 60 mg, cobalt sulfate 100 mg, copper sulfate 24 mg, ferrous sulfate 400 mg, zinc sulfate 174 mg, manganese sulfate 78 mg, magnesium sulfate 800 mg, sodium selenite 50 mg, and zeolite powder 3.114 g.

[0045] Example 1 Preparation of functional feed

[0046] The preparation method of Caragana korshinskii extract comprises the following steps:

[0047] (1) After crushing the branches of Caragana korshinskii, water (solid-liquid ratio is 1:4) is added, and the mixture is fully homogenized with the aid of a homogenizer to obtain a mixture D;

[0048] (2) The mixture D was placed in a water bath and extracted at 85° C. for 3 h. The Caragana korshinskii branches were removed by filtration. The mixture was then subjected to rotary evaporation and spray drying to obtain a Caragana korshinskii extract. The yield of the Caragana korshinskii extract was calculated to be 5.5%.

[0049] The raw materials for preparing the functional feed are as follows by weight: 46 parts of Chilean fish meal, 5 parts of high-gluten flour, 4 parts of corn starch, 5 parts of corn gluten meal, 6 parts of soybean meal, 6 parts of brewer's yeast, 8 parts of chicken meal, 7 parts of fermented soybean meal, 3.68 parts of fine bran, 1 part of monocalcium phosphate, 0.4 parts of composite premix, 0.02 parts of vitamin C, 0.5 parts of choline chloride, 1 part of lecithin, 5 parts of mixed fish oil, and 0.8 parts of Caragana extract.

[0050] The functional feed preparation method comprises the following steps:

[0051] (1) crushing Chilean fish meal, high-gluten flour, corn starch, corn gluten meal, soybean meal, brewer's yeast, chicken meal, fermented soybean meal, fine bran and monocalcium phosphate, and then fully mixing to obtain a mixture A;

[0052] (2) Mixture A, composite premix, choline chloride, vitamin C and Caragana korshinskii extract are fully mixed, and then ultrafinely ground to obtain mixture B;

[0053] (3) Mixture B, lecithin and 0-8 wt % of mixed fish oil are fully mixed, and then water is added and mixed again to obtain mixture C;

[0054] (4) The mixture C is tempered to prepare an expanded pellet feed, and after drying, the remaining mixed fish oil is vacuum sprayed at 50-70° C., cooled, and sieved to obtain the functional feed. The mass fraction of crude protein in the functional feed is 52.35%, and the mass fraction of crude fat is 10.55%.

[0055] Example 2 Preparation of functional feed

[0056] The method for preparing the Caragana korshinskii extract comprises the following steps:

[0057] (1) After crushing the branches of Caragana korshinskii, water (solid-liquid ratio is 1:3) is added, and the mixture is fully homogenized with the aid of a homogenizer to obtain a mixture D;

[0058] (2) The mixture D was placed in a water bath and extracted at 80° C. for 3 h. The Caragana korshinskii branches were removed by filtration. The mixture was then subjected to rotary evaporation and spray drying to obtain a Caragana korshinskii extract. The yield of the Caragana korshinskii extract was calculated to be 5.9%.

[0059] The raw materials for preparing the functional feed are as follows by weight: 45 parts of Chilean fish meal, 4 parts of high-gluten flour, 3 parts of corn starch, 5 parts of corn gluten meal, 6 parts of soybean meal, 5 parts of brewer's yeast, 8 parts of chicken meal, 8 parts of fermented soybean meal, 5.88 parts of fine bran, 1 part of monocalcium phosphate, 1 part of composite premix, 0.02 parts of vitamin C, 0.5 parts of choline chloride, 1 part of lecithin, 5 parts of mixed fish oil, and 1.6 parts of Caragana extract.

[0060] The functional feed preparation method comprises the following steps:

[0061] (1) crushing Chilean fish meal, high-gluten flour, corn starch, corn gluten meal, soybean meal, brewer's yeast, chicken meal, fermented soybean meal, fine bran and monocalcium phosphate, and then fully mixing to obtain a mixture A;

[0062] (2) Mixture A, composite premix, choline chloride, vitamin C and Caragana korshinskii extract are fully mixed, and then ultrafinely ground to obtain mixture B;

[0063] (3) Mixture B, lecithin and 0-8 wt % of mixed fish oil are fully mixed, and then water is added and mixed again to obtain mixture C;

[0064] (4) The mixture C is tempered to prepare an expanded pellet feed, and after drying, the remaining mixed fish oil is vacuum sprayed at 50-70° C., cooled, and sieved to obtain the functional feed. The mass fraction of crude protein in the functional feed is 52.46%, and the mass fraction of crude fat is 10.19%.

[0065] Example 3 Preparation of functional feed

[0066] The method for preparing the Caragana korshinskii extract comprises the following steps:

[0067] (1) After crushing the branches of Caragana korshinskii, water (solid-liquid ratio is 1:3) is added, and the mixture is fully homogenized with the aid of a homogenizer to obtain a mixture D;

[0068] (2) The mixture D was placed in a water bath and extracted at 85° C. for 3 h. The Caragana korshinskii branches were removed by filtration. The mixture was then subjected to rotary evaporation and spray drying to obtain a Caragana korshinskii extract. The yield of the Caragana korshinskii extract was calculated to be 6.1%.

[0069] The raw materials for preparing the functional feed are as follows by weight: 45 parts of Chilean fish meal, 5 parts of high-gluten flour, 3 parts of corn starch, 5 parts of corn gluten meal, 5 parts of soybean meal, 5 parts of brewer's yeast, 8 parts of chicken meal, 7 parts of fermented soybean meal, 5.28 parts of fine bran, 1 part of monocalcium phosphate, 1 part of composite premix, 0.02 parts of vitamin C, 0.5 parts of choline chloride, 1 part of lecithin, 5 parts of mixed fish oil, and 3.2 parts of Caragana extract.

[0070] The functional feed preparation method comprises the following steps:

[0071] (1) crushing Chilean fish meal, high-gluten flour, corn starch, corn gluten meal, soybean meal, brewer's yeast, chicken meal, fermented soybean meal, fine bran and monocalcium phosphate, and then fully mixing to obtain a mixture A;

[0072] (2) Mixture A, composite premix, choline chloride, vitamin C and Caragana korshinskii extract are fully mixed, and then ultrafinely ground to obtain mixture B;

[0073] (3) Mixture B, lecithin and 0-8 wt % of mixed fish oil are fully mixed, and then water is added and mixed again to obtain mixture C;

[0074] (4) The mixture C is tempered to prepare an expanded pellet feed, and after drying, the remaining mixed fish oil is vacuum sprayed at 50-70° C., cooled, and sieved to obtain the functional feed. The mass fraction of crude protein in the functional feed is 51.47%, and the mass fraction of crude fat is 10.85%.

[0075] Example 4 Preparation of Caragana Elata Extract

[0076] The preparation method comprises the following steps:

[0077] (1) After crushing the branches of Caragana korshinskii, water (solid-liquid ratio is 2:5) is added, and the mixture is fully homogenized with the aid of a homogenizer to obtain a mixture D;

[0078] (2) The mixture D was placed in a water bath and extracted at 75° C. for 2 h. The Caragana korshinskii branches were removed by filtration. The mixture was then subjected to rotary evaporation and spray drying to obtain a Caragana korshinskii extract. The yield of the Caragana korshinskii extract was calculated to be 4.5%.

[0079] Comparative Example Comparative Feed Preparation

[0080] The raw materials for preparing the comparative feed were, by weight: 48 parts of Chilean fish meal, 6 parts of high-gluten flour, 5 parts of corn starch, 6 parts of corn gluten meal, 6 parts of soybean meal, 2 parts of brewer's yeast, 5 parts of chicken meal, 8 parts of fermented soybean meal, 5.48 parts of fine bran, 1 part of monocalcium phosphate, 0.4 parts of vitamin compound premix, 0.02 parts of vitamin C, 0.5 parts of choline chloride, 0.6 parts of mineral compound premix, 1 part of lecithin, 5 parts of mixed fish oil, and 0 parts of Caragana extract.

[0081] The preparation method comprises the following steps:

[0082] (1) crushing Chilean fish meal, high-gluten flour, corn starch, corn gluten meal, soybean meal, brewer's yeast, chicken meal, fermented soybean meal, fine bran and monocalcium phosphate, and then fully mixing to obtain a mixture A;

[0083] (2) Mixture A, composite premix, choline chloride, vitamin C and Caragana korshinskii extract are fully mixed, and then ultrafinely ground to obtain mixture B;

[0084] (3) Mixture B, lecithin and 0-8 wt % of mixed fish oil are fully mixed, and then water is added and mixed again to obtain mixture C;

[0085] (4) The mixture C is tempered to prepare an expanded pellet feed, and after drying, the remaining mixed fish oil is vacuum sprayed at 50-70° C., cooled, and sieved to obtain the functional feed. The mass fraction of crude protein in the feed is 52.01%, and the mass fraction of crude fat is 10.11%.

[0086] Performance Testing

[0087] 1. Component detection of Caragana korshinskii extract

[0088] The components of the Caragana korshinone extract obtained in Example 4 were detected by gas chromatography-mass spectrometry, and the results are shown in Table 1:

[0089] Table 1 Components of Caragana korshinskii extract

[0090]

[0091] 2. Breeding test

[0092] The functional feed prepared in Examples 1-3 and the comparative feed prepared in the comparative example were used to feed largemouth bass with an initial body weight of about 7.01 g, respectively. The feeding time was 8:00 and 17:00, and the fish were fed to satiety each time. The daily water change during the feeding process was about 30%. After 56 days, the growth rate was detected, the antioxidant capacity and tissue structure were analyzed, and the Aeromonas hydrophila was challenged.

[0093] Survival rate (%) = final number of fish / initial number of fish × 100;

[0094] Weight gain rate (%) = (final total weight of fish - initial total weight of fish) / initial total weight of fish × 100;

[0095] Feeding rate (% / d) = total amount of feed ingested / (final total weight of fish / 2+initial total weight of fish / 2) / 56×100.

[0096] ① The functional feed prepared in Examples 1-3 can promote the growth of largemouth bass

[0097] According to the breeding results of the comparative examples and the embodiments ( Figure 1 and 2 ) It can be concluded that, compared with the comparative example, the functional feeds prepared by Examples 1-3 can improve the weight gain rate and feeding rate of largemouth seabass, among which the weight gain rate and feeding rate of largemouth seabass fed with the functional feed prepared by Example 1 are significantly improved (P<0.05), indicating that the functional feeds prepared by Examples 1-3 can promote the growth of largemouth seabass.

[0098] ② The functional feed prepared in Examples 1-3 can improve the liver health and liver antioxidant capacity of largemouth bass

[0099] ALT (alanine aminotransferase) and AST (aspartate aminotransferase) are two important liver enzymes that are often used to assess liver health. ALT and AST are widely present in liver cells. When liver cells are damaged, ALT and AST are released into the blood, so their increased blood levels are usually a sign of liver damage. Figure 3 and Figure 4 The results showed that compared with the control example, the serum ALT and AST levels of the largemouth seabass fed with the functional feed prepared by Examples 1-3 were reduced, among which the ALT and AST levels of Example 1 were significantly lower than those of the control example (P<0.05), indicating that the liver health of the largemouth seabass fed with the functional feed prepared by Examples 1-3 was improved, and the effect of Example 1 was better.

[0100] T-AOC (total antioxidant capacity), T-SOD (total superoxide dismutase) and CAT (catalase) play an important role in removing free radicals from animal bodies, while MDA (malondialdehyde) has a certain toxic effect on aquatic animal cells. When fish liver is under stress, it will produce a large amount of superoxide free radicals, causing membrane lipid peroxidation. However, membrane lipid peroxidation is an important sign of cell membrane damage, and its reaction product is malondialdehyde. Figure 5-8 The results showed that compared with the control example, the T-AOC content and T-SOD activity of the liver of the largemouth bass fed with the functional feed prepared in Example 1 were significantly increased, while the malondialdehyde content was significantly reduced (P<0.05). This shows that the functional feed prepared in Example 1 can improve the antioxidant capacity of the liver of the largemouth bass, thereby promoting the liver health of the largemouth bass.

[0101] The destruction or abnormality of liver tissue structure (such as fibrosis and necrosis) is often a sign of liver disease. Chronic liver diseases, such as hepatitis and cirrhosis, can lead to structural destruction of liver tissue and affect its function. Fig. 9 As shown, with the increase of the amount of Caragana korshinskii extract added, the vacuolation degree of the liver of the largemouth bass decreased, and the vacuolation degree of the liver of the largemouth bass in Example 3 was the lowest. It shows that the functional feeds prepared in Examples 1-3 can maintain the integrity of the liver tissue structure of the largemouth bass and promote liver health, and within a certain range, the addition amount of Caragana korshinskii extract is positively correlated with the integrity of the liver tissue structure of the largemouth bass.

[0102] ③ The functional feed prepared in Example 1 can improve the immunity of largemouth bass

[0103] Fish have non-specific immunity and specific immunity. C3 (complement 3) can be used as an important indicator of fish non-specific immunity. IgM (immunoglobulin M) can play an important role in the non-specific immune system of fish. Maintaining a high level of IgM can improve the disease resistance of fish. Fig.10 As shown, compared with the control example, the contents of C3 and IgM in the serum of the largemouth seabass fed with the functional feed prepared in Example 1 increased significantly (P<0.05), indicating that adding an appropriate amount of Caragana korshinskii extract can improve the immune ability of the largemouth seabass.

[0104] ④ The functional feed prepared in Examples 1-3 can improve the ability of largemouth bass to resist Aeromonas hydrophila

[0105] Fig.12 The results showed that 24 hours after the Aeromonas hydrophila attack, the largemouth bass in the control group and Example 2 died, while there was no death in Example 1 and Example 3; 96 hours after the attack, the survival rate of each group was Example 3> Example 1> Example 2> Control Group. This shows that adding an appropriate amount of Caragana korshinskii extract to the feed can improve the ability of the largemouth bass to resist Aeromonas hydrophila and improve the survival rate of the largemouth bass.

[0106] In summary, the functional feed of the present invention, after culturing largemouth black bass for 56 days, Example 1 improves the weight gain rate and feeding rate of largemouth black bass; through the analysis of the antioxidant capacity and tissue structure of the liver of largemouth black bass, the functional feeds prepared in Examples 1-3 improve the antioxidant capacity and liver health of the liver of largemouth black bass, and Example 1 has the best effect; through the analysis of the C3 and IgM contents in the serum of largemouth black bass, Example 1 of the present invention can effectively improve the immunity of largemouth black bass; through the acute toxicity test, compared with the control example, the largemouth black bass in Examples 1 and 3 have the strongest ability to resist Aeromonas hydrophila.

[0107] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0108] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0109] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A functional feed for largemouth bass, characterized in that: By weight, it is composed of the following raw materials: 40-50 parts of Chilean fish meal, 2-8 parts of high-gluten flour, 2-8 parts of corn starch, 2-8 parts of corn gluten meal, 2-8 parts of soybean meal, 2-8 parts of brewer's yeast, 4-10 parts of chicken meal, 2-8 parts of fermented soybean meal, 2-10 parts of fine bran, 1 part of monocalcium phosphate, 1 part of composite premix, 0.02 parts of vitamin C, 0.5 parts of choline chloride, 1 part of lecithin, 5 parts of mixed fish oil, 0.8-6 parts of Caragana extract; The composite premix is ​​composed of the following raw materials per 1kg of functional feed: vitamin B1 10-11mg, riboflavin 8-9mg, pyridoxine hydrochloride 10-11mg, vitamin B12 0.2-0.3mg, vitamin K3 10-11mg, inositol 100-110mg, calcium pantothenate 20-22mg, niacin 50-52mg, folic acid 2-3mg, biotin 2-3mg, vitamin A (500,000 IU) 400-420mg, vitamin D 5-6mg, vitamin E (500,000 IU) 100-120mg, ethoxyquinoline 150-160mg, secondary powder 0.13-0.14g, potassium chloride 200-220mg, potassium iodide 60-65mg, cobalt sulfate 100-110mg, copper sulfate 24-26mg, ferrous sulfate 400-420mg; zinc sulfate 170-175mg, manganese sulfate 75-80mg, magnesium sulfate 800-820mg, sodium selenite 5-52mg, zeolite powder 3.0-3.5g; The Caragana extract is obtained by extracting Caragana branches in water. The content of terpenoid compounds in the Caragana branch extract is greater than 4wt%, and the content of organic acid esters is greater than 5wt%.

2. The functional feed according to claim 1, characterized in that By weight, it is composed of the following raw materials: 43-48 parts of Chilean fish meal, 3-6 parts of high-gluten flour, 2-5 parts of corn starch, 3-6 parts of corn gluten powder, 3-6 parts of soybean meal, 3-6 parts of brewer's yeast, 5-9 parts of chicken meal, 5-8 parts of fermented soybean meal, 5-10 parts of fine bran, 1 part of calcium dihydrogen phosphate, 1 part of composite premix, 0.02 parts of vitamin C, 0.5 parts of choline chloride, 1 part of lecithin, 5 parts of mixed fish oil and 0.8-4 parts of Caragana korshinskii extract.

3. The functional feed according to claim 1, characterized in that The added amount of the Caragana korshinskii extract is 0.8 parts.

4. A method for preparing the functional feed according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) crushing Chilean fish meal, high-gluten flour, corn starch, corn gluten meal, soybean meal, brewer's yeast, chicken meal, fermented soybean meal, fine bran and monocalcium phosphate, and then fully mixing to obtain a mixture A; (2) Mixture A, composite premix, choline chloride, vitamin C and Caragana korshinskii extract are fully mixed, and then ultrafinely ground to obtain mixture B; (3) fully mixing the mixture B, lecithin and 0-8 wt % of mixed fish oil, then adding water and mixing again to obtain a mixture C; (4) The mixture C is subjected to conditioning treatment to prepare an expanded pellet feed, and after drying, the mixture is vacuum sprayed with the remaining mixed fish oil at 50-70° C., and the functional feed is obtained after cooling and sieving.

5. The preparation method according to claim 4, characterized in that: The preparation method of the Caragana orientalis extract comprises the following steps: (1) Crush the branches of Caragana korshinskii, add water, and fully homogenize with the aid of a homogenizer to obtain a mixture D; (2) placing the mixture D in a water bath for extraction, filtering to remove the Caragana korshinskii branches, and then subjecting the mixture to rotary evaporation and spray drying to obtain the Caragana korshinskii extract; The solid-liquid ratio of the Caragana korshinskii branches to water is 1-4:2-10, the extraction temperature is 70-90° C., and the extraction time is 1-3 hours.

6. The preparation method according to claim 5, characterized in that: The solid-liquid ratio of the Caragana korshinskii branches to water is 1-3:2-8, the extraction temperature is 75-90° C., and the extraction time is 2-3 hours.

7. The preparation method according to claim 5, characterized in that: The solid-liquid ratio of the Caragana korshinskii branches to water is 1-2:4-6, the extraction temperature is 80-90° C., and the extraction time is 2.5-3 hours.

8. Use of the functional feed according to claim 1 or 2 in improving liver health of largemouth bass.

9. Use of the functional feed according to claim 1 or 2 in resisting Aeromonas hydrophila infection of largemouth bass.

10. Use of the functional feed according to claim 1 or 2 in improving the immunity of largemouth bass.

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