Disease-preventing nutritional compound Chinese herbal medicine river crab feed additive and preparation method thereof

Abstract

The invention belongs to the technical field of aquaculture, and particularly relates to a disease-preventing nutritional compound Chinese herbal medicine river crab feed additive and a preparation method thereof. The Chinese herbal medicine components of the additive comprise astragalus membranaceus, hawthorn, pericarpium citri reticulatae, radix isatidis, oriental wormwood, coptis chinensis and allicin. The feed additive is high in stability in water, simple in component and stable in property, can enhance the disease resistance and immunity of the river crabs, reduces the generation of drug resistance of pathogenic bacteria, realizes the dual effects of disease prevention and growth promotion, and effectively improves the meat quality of the river crabs at the same time. In addition, the preparation method provided by the invention is simple in process, convenient to operate and easy to realize industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aquaculture, and particularly relates to a disease-preventing and nutrition-combining Chinese herbal medicine river crab feed additive and a preparation method thereof. BACKGROUND

[0002] As an important freshwater crustacean in China, river crab has a growing market demand due to its delicious and nutritious meat, and the cultivation scale is expanding year by year. With the popularization of the cultivation scale, the river crab cultivation process not only faces the problems of slow growth, weak disease prevention ability, and nutritional deficiency, but also has the problems of the abuse of antibiotics and heavy metal drugs, which causes the pathogenic bacteria to have enhanced drug resistance, thereby leading to the decline of the immunity of river crab and limiting the rapid, healthy and green development of the river crab cultivation industry. River crab is an omnivorous organism, and its food sources are diverse, mainly including traditional bait and artificial compound feed. The traditional bait includes natural bait such as plankton and various aquatic plants in the water environment, and animal bait such as artificially fed snails, small shrimps, and small fish. The long-term dependence of river crab cultivation on traditional bait leads to uneven nutrition and water pollution, affecting the quality. In comparison, the full-time feeding of compound feed not only has balanced nutrition, stable source and convenient operation, but also meets the growth needs of river crab, improves the quality and reduces the cost.

[0003] The artificial compound feed can provide an important material basis for the growth of river crab, and the nutritional composition and additives of the feed directly affect the growth, disease prevention ability and nutritional quality of the meat of river crab. How to develop efficient and environmentally friendly functional feed and additives for river crab to replace traditional bait cultivation has become the core direction of the field of aquatic research.

[0004] CN201510048130.7 discloses a puffed biological feed for improving the immunity of river crab, and the raw materials include the following components: fish slurry, earthworm slurry, soybean meal, rapeseed meal, cottonseed meal, flour, rice bran, fish oil, soybean oil, river crab premix, and sea beach mallow root powder, which are used to enhance the resistance of river crab. However, the stability of the feed in water is not good, and it is easy to become paste, polluting the water source.

[0005] CN201610831605.4 discloses a feed additive for improving the immunity and antioxidant capacity of river crab, which includes the following components: tea polysaccharide, tea red pigment, tea amino acid, lycopene, and immunopolysaccharide. The feed additive has low raw material cost and is easy to obtain, which meets the requirements of low-cost feed of breeders, but has the defects of weak disease resistance and instability in water.

[0006] CN201710918529.5 discloses a kind of river crab fattening period feed and preparation method thereof, raw materials include: fish meal, shellfish meal, pork meal, insect powder, corn flour, black rice powder, fermented rapeseed meal, fermented soybean meal, sunflower seed powder, yam powder, lotus root powder, seaweed powder, matcha powder, fish, liquorice, complex enzyme preparation, rare earth, chitosan, mineral salt, provide feed and nutrient for river crab fattening period.This feed component is complex, cost is higher, and only improves fattening effect.

[0007] CN201710917954.2 discloses a kind of river crab immunity improves digestion feed, feed contains pork, insect powder, shrimp powder, fermented blood powder, corn flour, fermented soybean meal, black rice powder, bran, cottonseed meal, cucumber seed powder, waxgourd powder, feather meal, seaweed powder, green tea powder and a variety of nutrient substances, also contains probiotics, complex enzyme preparation and Chinese herbal medicine extract, feed component is relatively complex, needs to strictly control the proportion of each component.

[0008] CN201811002652.3 discloses a kind of river crab feed containing compound probiotics and Chinese herbal medicine, feed is added with compound probiotic preparation, for example, bacillus licheniformis, bacillus pumilus, bifidobacterium bifidum, enterococcus lactis, enterococcus lactis, lactobacillus bulgaricus, etc., also adds radix codonopsis, atractylodes, poria cocos, liquorice, atractylodes lancea, cardamom, dried tangerine or orange peel, etc.Chinese herbal medicine, through the cooperation of probiotics and Chinese herbal medicine, aims to improve the disease resistance of river crab and improve yield, the additive is mainly for the main functions of tonifying qi and spleen, regulating qi and reducing swelling, mild tonifying, and the disease resistance function is lack.

[0009] In the existing river crab feed additive technology, there are generally problems such as poor water stability of additives, complex components, unstable quality, etc.Some chemical synthetic additives have potential drug residue hidden dangers, which are not consistent with the trend of green breeding.Under the complex environmental stress brought by intensive breeding, conventional additives often have single function, and it is difficult to consider the multiple functions of promoting growth, resisting disease and improving meat quality.Therefore, how to develop a new type of feed additive with high disease resistance, low drug resistance and can significantly improve the immunity and comprehensive quality of river crab is a key technical problem to be solved in current river crab breeding industry. SUMMARY

[0010] In view of the problems of poor disease resistance, pathogenic bacteria prone to drug resistance and insufficient stability of feed additives in the prior art, the present application provides a kind of disease prevention and nutrition compound Chinese herbal medicine river crab feed additive and preparation method.The feed additive has high water stability, simple components and stable properties, can enhance the disease resistance and immunity of river crab, reduce the generation of pathogenic bacteria drug resistance, realize the dual functions of disease prevention and growth promotion, and effectively improve the meat quality of river crab.In addition, the preparation method provided by the present application is simple, easy to operate and easy to realize industrial production.

[0011] The technical scheme of the present application is: a disease-preventing and nutrition-boosting compound Chinese herbal medicine river crab feed additive, wherein the Chinese herbal medicine component of the additive comprises Astragalus membranaceus, hawthorn, dried tangerine or orange peel, Isatidis radix, Capillari, Coptis chinensis, and garlicin.

[0012] Preferably, in the additive, the weight proportions of the Chinese herbal medicine component are as follows: 10-40 parts of Astragalus membranaceus, 5-35 parts of hawthorn, 5-45 parts of dried tangerine or orange peel, 8-55 parts of Isatidis radix, 5-45 parts of Capillari, 1-8 parts of Coptis chinensis, and 8-50 parts of garlicin.

[0013] Further preferably, in the additive, the weight proportions of the Chinese herbal medicine component are as follows: 20 parts of Astragalus membranaceus, 15 parts of hawthorn, 15 parts of dried tangerine or orange peel, 15 parts of Isatidis radix, 15 parts of Capillari, 5 parts of Coptis chinensis, and 15 parts of garlicin.

[0014] Preferably, the additive further comprises probiotics, sodium alginate, and malt dextrin.

[0015] Preferably, in the additive, the addition amount of probiotics is 0.5-0.8% of the weight of the Chinese herbal medicine component.

[0016] Further preferably, the probiotics are Bacillus subtilis or Bacillus licheniformis.

[0017] Preferably, in the additive, the addition amount of sodium alginate is 1-3% of the weight of the Chinese herbal medicine component.

[0018] Preferably, in the additive, the addition amount of malt dextrin is 2-5% of the weight of the Chinese herbal medicine component.

[0019] As a second aspect of the present application, a preparation method of the river crab feed additive is provided, comprising the following steps: grinding Astragalus membranaceus, hawthorn, dried tangerine or orange peel, Isatidis radix, Capillari, and Coptis chinensis to 40-80 mesh respectively, mixing uniformly, using ultrasonic-assisted extraction, centrifugal separation after the extraction is completed, collecting the supernatant, and reducing pressure to obtain extract; then adding the obtained extract, garlicin, sodium alginate, and malt dextrin into isopropanol with a volume fraction of 20-30%, stirring, sterilizing, filtering, and freeze-drying to obtain additive powder; finally, adding probiotic freeze-dried powder and mixing uniformly to obtain the additive.

[0020] Preferably, in the method, the frequency of ultrasonic-assisted extraction is 40-55 kHz, and the time is 40-60 min.

[0021] Preferably, in the method, the volume fraction of ethanol used as the extraction solvent is 15-25% during ultrasonic-assisted extraction.

[0022] Preferably, in the method, the freeze-drying step is performed at -40 to -45 ℃ for 8-10 h.

[0023] As a third aspect of the present application, there is provided a disease-preventing and nutrition-aiding compound Chinese herbal feed for river crab, which comprises cottonseed meal, peanut meal, meat and bone meal, soybean oil, betaine, vitamin E, calcium hydrogen phosphate, potassium chloride, zinc methionine, lysine, tryptophan, magnesium sulfate, potassium iodide and the above-mentioned feed additive.

[0024] Preferably, the weight proportions of the components in the feed are as follows: cottonseed meal 20-35 parts, peanut meal 10-20 parts, meat and bone meal 20-40 parts, soybean oil 5-8 parts, betaine 0.4-0.7 parts, vitamin E 0.3-0.6 parts, calcium hydrogen phosphate 2-3 parts, potassium chloride 0.2-0.5 parts, zinc methionine 0.1-0.3 parts, lysine 0.3-0.5 parts, tryptophan 0.3-0.5 parts, magnesium sulfate 0.5-0.8 parts, potassium iodide 0.1-0.3 parts and the above-mentioned feed additive 10-18 parts.

[0025] As a fourth aspect of the present application, there is provided a preparation method of the disease-preventing and nutrition-aiding compound Chinese herbal feed for river crab, which comprises the following steps: mixing the components except for soybean oil, vitamin E and the additive uniformly in a blender, conditioning by microwave radiation and heating in reverse, then granulating, and after cooling to room temperature, adding soybean oil, vitamin E and the prepared feed additive, and stirring uniformly to obtain the river crab feed.

[0026] Preferably, in the method, when heated by microwave radiation, the power is set to 500-800 W, the radiation time is 30-50 min, and a pulse mode of 40 s on / 20 s off is adopted to avoid local overheating.

[0027] Compared with the prior art, the present application has the following outstanding advantages: 1. The feed additive obtained by the present application has the following advantages: through the synergistic effect of sodium alginate and malt dextrin, the malt dextrin is adsorbed on the sodium alginate to form a strong gel system when meeting water, thereby improving the stability of the additive in water, effectively activating the immune system of the river crab, improving its disease resistance, and reducing the generation of pathogen resistance from the source.

[0028] 2. The feed additive obtained by the present application also has the comprehensive effects of promoting the growth of river crab and improving meat quality, and has high application value.

[0029] 2. In terms of preparation process, the present application adopts a simplified production process route, has low requirements for equipment, is simple and easy to operate and easy to control quality, is very suitable for industrialized continuous production, can effectively reduce production cost and improve production efficiency. DETAILED DESCRIPTION

[0030] The following detailed description of the embodiments is provided for further explanation of the present application, but does not limit the scope of the present application in any way. Those skilled in the art can make various modifications or improvements to the present application according to the basic idea of the present application, but as long as they do not deviate from the basic idea of the present application, they are within the scope of the present application.

[0031] In Example 1, 100 g of Huangqi, 50 g of Shanzha, 50 g of Chenpi, 80 g of Banlangen, 450 g of Yincheng, and 80 g of Huanglian were respectively crushed to 40-80 meshes, mixed uniformly, and then subjected to ultrasonic-assisted extraction at a frequency of 40 kHz for 40 min using 15% ethanol as the extraction solvent. After the extraction, centrifugal separation was performed, the supernatant was collected, and the extraction was repeated once. The supernatants were collected and concentrated under reduced pressure to obtain an extract. Then, 500 g of allicin, 13 g of sodium alginate, and 26 g of maltodextrin were added to 20% isopropanol, stirred, sterilized, filtered, and freeze-dried at -40 to -45°C for 8-10 h to obtain an additive powder. Finally, 10 g of Bacillus subtilis freeze-dried powder was added at 10-20°C, and the mixture was uniformly mixed to obtain the additive.

[0032] In Example 1, 100 g of Huangqi, 50 g of Shanzha, 50 g of Chenpi, 80 g of Banlangen, 450 g of Yincheng, and 80 g of Huanglian were respectively crushed to 40-80 meshes, mixed uniformly, and then subjected to ultrasonic-assisted extraction at a frequency of 40 kHz for 40 min using 15% ethanol as the extraction solvent. After the extraction, centrifugal separation was performed, the supernatant was collected, and the extraction was repeated once. The supernatants were collected and concentrated under reduced pressure to obtain an extract. Then, 500 g of allicin, 13 g of sodium alginate, and 26 g of maltodextrin were added to 20% isopropanol, stirred, sterilized, filtered, and freeze-dried at -40 to -45°C for 8-10 h to obtain an additive powder. Finally, 10 g of Bacillus subtilis freeze-dried powder was added at 10-20°C, and the mixture was uniformly mixed to obtain the additive.

[0033] In Example 2, 200 g of Huangqi, 150 g of Shanzha, 150 g of Chenpi, 150 g of Banlangen, 150 g of Yincheng, and 50 g of Huanglian were respectively crushed to 40-80 meshes, mixed uniformly, and then subjected to ultrasonic-assisted extraction at a frequency of 50 kHz for 45 min using 20% ethanol as the extraction solvent. After the extraction, centrifugal separation was performed, the supernatant was collected, and the extraction was repeated once. The supernatants were collected and concentrated under reduced pressure to obtain an extract. Then, 150 g of allicin, 20 g of sodium alginate, and 40 g of maltodextrin were added to 25% isopropanol, stirred, sterilized, filtered, and freeze-dried at -40 to -45°C for 8-10 h to obtain an additive powder. Finally, 6 g of Bacillus subtilis freeze-dried powder was added at 10-20°C, and the mixture was uniformly mixed to obtain the additive.

[0034] Mix 2.7 kg of cottonseed meal, 1.5 kg of peanut meal, 3 kg of meat and bone meal, 0.06 kg of betaine, 0.25 kg of dicalcium phosphate, 0.04 kg of potassium chloride, 0.02 kg of zinc methionine, 0.04 kg of lysine, 0.04 kg of tryptophan, 0.06 kg of magnesium sulfate, and 0.02 kg of potassium iodide in a mixer until homogeneous. Then, heat and condition the mixture using microwave radiation at 700W for 40 minutes with a pulse mode of 40 seconds on and 20 seconds off. After granulation, cool the granules to room temperature and then add 0.65 kg of soybean oil, 0.05 kg of vitamin E, and 1.0 kg of the prepared feed additive. Mix well to obtain the crab feed.

[0035] In Example 3, 400g of Astragalus membranaceus, 350g of Crataegus pinnatifida, 450g of Citrus reticulata peel, 550g of Isatis indigotica root, 50g of Artemisia capillaris, and 10g of Coptis chinensis were pulverized to 40-80 mesh, mixed evenly, and then extracted using ultrasound-assisted extraction at a frequency of 55kHz for 60 minutes. The extraction solvent was 25% ethanol (v / v). After extraction, the mixture was centrifuged, and the supernatant was collected. The extraction was repeated once, and the supernatants were collected and combined. The extract was then concentrated under reduced pressure to obtain an extract. The obtained extract was then added to 30% isopropanol (v / v) along with 80g of allicin, 57g of sodium alginate, and 95g of maltodextrin. The mixture was stirred, sterilized, filtered, and freeze-dried at -40 to -45℃ for 8-10 hours to obtain an additive powder. Finally, 9g of Bacillus licheniformis freeze-dried powder was added at 10-20℃ and mixed evenly to obtain the additive.

[0036] Mix 3.5 kg of cottonseed meal, 2 kg of peanut meal, 4 kg of meat and bone meal, 0.07 kg of betaine, 0.3 kg of dicalcium phosphate, 0.05 kg of potassium chloride, 0.03 kg of zinc methionine, 0.05 kg of lysine, 0.05 kg of tryptophan, 0.08 kg of magnesium sulfate, and 0.03 kg of potassium iodide in a mixer until homogeneous. Then, heat and condition the mixture using microwave radiation at 800W for 30 minutes with a pulse mode of 40s on / 20s off. After granulation, cool the granules to room temperature and then add 0.8 kg of soybean oil, 0.06 kg of vitamin E, and 1.8 kg of the prepared feed additive. Mix well to obtain the river crab feed.

[0037] In Comparative Example 1, 2.7 kg of cottonseed meal, 1.5 kg of peanut meal, 3 kg of meat and bone meal, 0.06 kg of betaine, 0.25 kg of dicalcium phosphate, 0.04 kg of potassium chloride, 0.02 kg of zinc methionine, 0.04 kg of lysine, 0.04 kg of tryptophan, 0.06 kg of magnesium sulfate, and 0.02 kg of potassium iodide were mixed evenly in a mixer. The mixture was then conditioned using microwave radiation with a tumbling heating setting at 700 W for 40 min, using a pulse mode of 40 s on / 20 s off. After granulation, the granules were cooled to room temperature, and then 0.65 kg of soybean oil and 0.05 kg of vitamin E were added and mixed evenly to obtain the crab feed.

[0038] In Comparative Example 2, 200g of Astragalus membranaceus, 150g of Crataegus pinnatifida, 150g of Citrus reticulata peel, 150g of Isatis indigotica root, 150g of Artemisia capillaris, and 50g of Coptis chinensis were pulverized to 40-80 mesh, mixed evenly, and then extracted using ultrasound-assisted extraction at a frequency of 50kHz for 45 minutes. The extraction solvent was 20% ethanol (v / v). After extraction, the mixture was centrifuged, and the supernatant was collected. The extraction was repeated once, and the supernatants were collected and combined. The extract was then concentrated under reduced pressure to obtain an extract. The obtained extract was then added to 150g of allicin in 25% isopropanol (v / v), stirred, sterilized, filtered, and freeze-dried at -40 to -45℃ for 8-10 hours to obtain an additive powder. Finally, 6g of Bacillus subtilis freeze-dried powder was added at 10-20℃ and mixed evenly to obtain the additive.

[0039] Mix 2.7 kg of cottonseed meal, 1.5 kg of peanut meal, 3 kg of meat and bone meal, 0.06 kg of betaine, 0.25 kg of dicalcium phosphate, 0.04 kg of potassium chloride, 0.02 kg of zinc methionine, 0.04 kg of lysine, 0.04 kg of tryptophan, 0.06 kg of magnesium sulfate, and 0.02 kg of potassium iodide in a mixer until homogeneous. Then, heat and condition the mixture using microwave radiation at 700W for 40 minutes with a pulse mode of 40 seconds on and 20 seconds off. After granulation, cool the granules to room temperature and then add 0.65 kg of soybean oil, 0.05 kg of vitamin E, and 1.0 kg of the prepared feed additive. Mix well to obtain the crab feed.

[0040] In Comparative Example 3, 200g of Astragalus membranaceus, 150g of Crataegus pinnatifida, 150g of Citrus reticulata peel, 150g of Isatis indigotica root, 150g of Artemisia capillaris, and 50g of Coptis chinensis were pulverized to 40-80 mesh, mixed evenly, and then extracted using ultrasound-assisted extraction at a frequency of 50kHz for 45 minutes. The extraction solvent was 20% ethanol (v / v). After extraction, the mixture was centrifuged, and the supernatant was collected. The extraction was repeated once, and the supernatants were collected and combined. The extract was then concentrated under reduced pressure to obtain an extract. The obtained extract was then added to 25% isopropanol (v / v) along with 150g of allicin, 20g of sodium alginate, and 40g of maltodextrin. The mixture was stirred, sterilized, filtered, and freeze-dried at -40 to -45℃ for 8-10 hours to obtain an additive.

[0041] Mix 2.7 kg of cottonseed meal, 1.5 kg of peanut meal, 3 kg of meat and bone meal, 0.06 kg of betaine, 0.25 kg of dicalcium phosphate, 0.04 kg of potassium chloride, 0.02 kg of zinc methionine, 0.04 kg of lysine, 0.04 kg of tryptophan, 0.06 kg of magnesium sulfate, and 0.02 kg of potassium iodide in a mixer until homogeneous. Then, heat and condition the mixture using microwave radiation at 700W for 40 minutes with a pulse mode of 40 seconds on and 20 seconds off. After granulation, cool the granules to room temperature and then add 0.65 kg of soybean oil, 0.05 kg of vitamin E, and 1.0 kg of the prepared feed additive. Mix well to obtain the crab feed.

[0042] In Comparative Example 4, 200g of Astragalus membranaceus, 150g of Crataegus pinnatifida, 150g of Citrus reticulata peel, 150g of Isatis indigotica root, 150g of Artemisia capillaris, and 50g of Coptis chinensis were pulverized to 40-80 mesh, mixed evenly, and then extracted using ultrasound-assisted extraction at a frequency of 50kHz for 45 minutes. The extraction solvent was 20% ethanol (v / v). After extraction, the mixture was centrifuged, and the supernatant was collected. The extraction was repeated once, and the supernatants were collected and combined. The extract was then concentrated under reduced pressure to obtain an extract. The obtained extract was then added to 25% isopropanol (v / v) along with 150g of allicin, 20g of sodium alginate, and 40g of maltodextrin. The mixture was stirred, sterilized, filtered, and freeze-dried at -40 to -45℃ for 8-10 hours to obtain an additive powder. Finally, 6g of Bacillus subtilis freeze-dried powder was added at 10-20℃ and mixed evenly to obtain the additive.

[0043] Mix 2.7 kg of cottonseed meal, 1.5 kg of peanut meal, 3 kg of meat and bone meal, 0.06 kg of betaine, 0.25 kg of dicalcium phosphate, 0.04 kg of potassium chloride, 0.02 kg of zinc methionine, 0.04 kg of lysine, 0.04 kg of tryptophan, 0.06 kg of magnesium sulfate, and 0.02 kg of potassium iodide in a mixer until homogeneous. Then, heat the mixture with hot air to 100-110°C, granulate it, and after the granules have cooled to room temperature, add 0.65 kg of soybean oil, 0.05 kg of vitamin E, and 1.0 kg of the prepared feed additive. Mix well to obtain the river crab feed.

[0044] Verification of the implementation examples, 1. Toxicity test In accordance with the requirements of the "Technical Guidelines for Single-Dose Toxicity Studies of Drugs," single-dose toxicity tests were conducted on the crab feed additives prepared in Examples 1-3 of this invention. The tests were conducted via gavage, with three experimental groups of 50 mice in each group. The specific experimental results are as follows: Under maximum dosage and concentration conditions, mice administered the feed additives obtained in Examples 1-3 via gavage exhibited transient decreased activity after doses of 323 g / kg, 318 g / kg, and 310 g / kg, respectively, which gradually returned to normal. No deaths occurred in any of the 50 mice in each group during the experiment. Approximately one hour after administration, the mice's behavior and activity essentially returned to normal. During the 6-month observation period, the mice showed normal weight gain and no obvious abnormal symptoms, indicating that the crab feed additives obtained in this invention have good safety.

[0045] 2. (1) Investigation on the growth of river crabs The river crabs used in the experiment were purchased from Dongying Huize Agricultural Technology Co., Ltd. The breeding experiment was conducted at the Aquatic Teaching and Research Base of Dongying Vocational College. 350 river crabs (initial weight approximately 50g) were selected. Inclusion criteria included good health, intact appendages, and uniform body shape. They were randomly divided into 7 groups of 50 crabs each. Under identical rearing conditions and feeding methods, the groups were isolated and raised separately. Groups 1-7 were fed the feeds provided in Examples 1-3 and Comparative Examples 1-4, respectively. Feeding was conducted twice daily at 9:00 AM and 4:00 PM, with the feed amount controlled at 5% of the crab's wet weight. The breeding experiment lasted 60 days. After the experiment, the weight gain and survival rate of the crabs were recorded. Specific results are shown in the table below.

[0046]

[0047] The results showed that the crab feed and additives prepared according to the embodiments of the present invention significantly improved the disease resistance and growth of crabs. This confirms that the feed provided by the present invention is nutritionally balanced, energy-rich, and possesses excellent disease resistance, effectively enhancing the crab's resistance and promoting its healthy growth. In experimental group 4, the absence of the additives described in the present invention in the feed resulted in poor disease resistance, poor growth, and a significantly reduced survival rate in the crabs. In experimental group 5, the absence of sodium alginate and maltodextrin in the feed additives led to decreased stability of the additives in water, preventing the crabs from effectively feeding, thus resulting in poor disease resistance and growth. In experimental group 6, the absence of beneficial bacteria in the feed additives negatively impacted the disease resistance and growth of the crabs to some extent. In experimental group 7, the different preparation method of the feed compared to the embodiments slightly affected the disease resistance and growth of the crabs.

[0048] (2) Examination of the muscle quality of river crabs The contents of inosinic acid and guanylic acid in the muscle of the above-mentioned river crabs were detected by high performance liquid chromatography. Simultaneously, a sensory evaluation panel was established to comprehensively score the crabs based on their appearance, activity level, taste, aroma (including fragrance and earthy smell), and muscle toughness. The scoring system used a scale of 1 to 5 points, where 'good' was scored as 5 points, 'fairly good' as 4 points, 'average' as 3 points, 'poor' as 2 points, and 'very poor' as 1 point.

[0049]

[0050] The results show that this invention can significantly improve the quality and flavor of river crabs. Experimental data show that, compared to the feed and additives used in the comparative examples, river crabs fed the product of this invention have higher levels of inosinic acid and guanylic acid (key flavor compounds) in their muscle. Simultaneously, the appearance, physiological activity, taste, and aroma of the river crabs are significantly improved, thus significantly increasing their commercial value.

Claims

1. A disease-preventing and nutritional compound herbal feed additive for river crabs, characterized in that, The herbal ingredients in the additive include astragalus, hawthorn, tangerine peel, isatis root, artemisia capillaris, coptis, and allicin.

2. The additive as described in claim 1, characterized in that, The additive contains the following components by weight: Astragalus membranaceus 10-40 parts, Crataegus pinnatifida 5-35 parts, Citrus reticulata 5-45 parts, Isatis indigotica 8-55 parts, Artemisia capillaris 5-45 parts, Coptis chinensis 1-8 parts, and Allicin 8-50 parts.

3. The additive as described in claim 1, characterized in that, The additives also include probiotics, sodium alginate, and maltodextrin.

4. The additive as described in claim 3, characterized in that, In the additive, the amount of probiotics added is 0.5 to 0.8% of the weight of the herbal medicine components.

5. The additive as described in claim 3, characterized in that, In the additive, the amount of sodium alginate added is 1-3% of the weight of the herbal medicine components.

6. The additive as described in claim 3, characterized in that, In the additive, the amount of maltodextrin added is 2-5% of the weight of the herbal medicine components.

7. A method for preparing the additive as described in claim 3, characterized in that, The preparation method includes the following steps: Astragalus membranaceus, hawthorn, tangerine peel, isatis root, artemisia capillaris, and coptis chinensis are pulverized to 40-80 mesh, mixed evenly, and extracted using ultrasound-assisted extraction. After extraction, the extract is centrifuged, the supernatant is collected, and concentrated under reduced pressure to obtain an extract. Then, the obtained extract is added to isopropanol at a volume fraction of 20-30% along with allicin, sodium alginate, and maltodextrin. The mixture is stirred, sterilized, filtered, and freeze-dried to obtain an additive powder. Finally, freeze-dried probiotic powder is added and mixed evenly to obtain the additive.

8. The preparation method according to claim 7, characterized in that, In the method described, during ultrasound-assisted extraction, ethanol with a volume fraction of 15-25% is used as the extraction solvent.

9. A disease-preventing and nutritional compound herbal feed for river crabs containing any one of the additives claimed in claims 1 to 6, characterized in that, The feed includes: cottonseed meal, peanut meal, meat and bone meal, soybean oil, betaine, vitamin E, dicalcium phosphate, potassium chloride, zinc methionine, lysine, tryptophan, magnesium sulfate, potassium iodide, and the above-mentioned feed additives.

10. The feed as described in claim 9, characterized in that, The weight proportions of each component in the feed are as follows: 20-35 parts cottonseed meal, 10-20 parts peanut meal, 20-40 parts meat and bone meal, 5-8 parts soybean oil, 0.4-0.7 parts betaine, 0.3-0.6 parts vitamin E, 2-3 parts dicalcium phosphate, 0.2-0.5 parts potassium chloride, 0.1-0.3 parts zinc methionine, 0.3-0.5 parts lysine, 0.3-0.5 parts tryptophan, 0.5-0.8 parts magnesium sulfate, 0.1-0.3 parts potassium iodide, and 10-18 parts of the above feed additives.

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