Application of radix scrophulariae extract in prevention and control of food-borne enteritis of carnivorous fishes

Abstract

The invention relates to the field of utilization of Chinese herbal medicine radix scrophulariae, and discloses a preparation method of a radix scrophulariae extract, which comprises the following steps: S1, taking dried radix scrophulariae as a raw material, crushing and sieving; s2, adding 85-95% ethanol solution according to the proportion of 3 times of the mass of the radix scrophulariae; s3, extracting for 3 times under a reflux condition, and extracting for 4 hours each time; s4, combining the extracting solutions, and recovering the solvent to obtain a radix scrophulariae extract; the dried radix scrophulariae roots in the step S1 are fine powder passing through a 100-mesh sieve; the temperature of reflux extraction in the step S3 is 75-90 DEG C; the extracting solution subjected to reflux extraction in the step S3 is subjected to vacuum concentration. It is found through tests that 2-4 [mu] g / mL of the radix scrophulariae extract can significantly inhibit LPS-induced Caco2 cell inflammation and is non-toxic to cells, and soybean saponin-induced zebra fish food-borne enteritis is reduced, including the transcriptional level of proinflammatory factors I < L1beta > and I < L8 > in intestinal tracts.

Description

Technical Field

[0001] The invention relates to the technical field of utilization of Chinese herbal medicine Scrophularia ningpoensis, and specifically to application of Scrophularia ningpoensis extract in preventing and controlling foodborne enteritis in carnivorous fish. Background Art

[0002] The intestine is a key organ for digestion and absorption of nutrients in animals, and it also plays a vital role as an immune organ. At present, fish enteritis is mainly divided into bacterial enteritis, viral enteritis and food-borne enteritis. Among them, food-borne enteritis is mainly caused by the presence of various anti-nutritional factors (soybean saponins, trypsin inhibitors, antigenic proteins, etc.) in plant protein sources such as soybean meal, cottonseed meal, and rapeseed meal.

[0003] With the rapid development of the global aquaculture industry, fish meal is in short supply. The application of plant protein sources in aquatic feed has increased year by year due to its stable output and low price. This has also led to frequent foodborne enteritis in fish, especially carnivorous fish (pearl grouper, turbot, largemouth bass, rainbow trout, Atlantic sea bream, black sea bream and spotted sea bass, etc.). This is because the anti-nutritional factors in plant-based proteins have potential effects on the metabolism of carnivorous fish, including increasing intestinal permeability, interfering with lipid and protein digestion, and changing the digestion and metabolism of cholesterol and bile salts.

[0004] Foodborne enteritis is a common disease in carnivorous fish, with shortened mucosal folds, increased goblet cells, swelling of the lamina propria and subepithelial mucosa, and strong infiltration of inflammatory cells as its main symptoms. It not only causes intestinal damage in fish and seriously affects the digestion and absorption of nutrients, but also reduces feed utilization and increases nitrogen and phosphorus emissions in water bodies, seriously affecting the green and sustainable development of aquaculture.

[0005] At present, the prevention and treatment methods for enteritis in carnivorous fish focus on the use of antibiotics. However, this is inconsistent with the national policy of green and healthy aquaculture. Chinese herbal medicine, as a feed additive that is both medicinal and edible, has the characteristics of being green, efficient, and environmentally friendly. It has a strong effect of inhibiting inflammation and has been proven to be effective in treating enteritis in pearl grouper.

[0006] Scrophularia is one of the commonly used traditional Chinese medicinal materials in my country. It is the dried root of Scrophularia ningpoens is Hems l., a plant of the Scrophulariaceae family. It was first recorded in Shennong's Herbal Classic and was listed as a medium-grade product. There are more than 200 species of Scrophularia plants in the world. It is a large genus of the Scrophulariaceae family. It is distributed in the temperate zones of Europe and Asia. There are many species in the Mediterranean region, only a few species in the Americas, and about 40 species in my country. The main active ingredients of Scrophularia are iridoid glycosides, phenylpropanoids, polysaccharides, flavonoids and organic acids. Modern pharmacological studies have shown that Scrophularia has cardiovascular and cerebrovascular protection, anti-inflammatory, antioxidant, anti-tumor, liver protection and hypoglycemic effects. For example, studies have found that Scrophularia extracts affect the expression of inflammatory factors such as IL-6, IL-5, IL-13, IL-17, IL-1β and TNF-α, and may be related to the regulation of NF-kB signal transduction pathway activation. However, it is still unknown whether Scrophularia ningpoensis extract or Scrophularia ningpoensis ultrafine powder as feed additives are effective in treating foodborne enteritis in carnivorous fish. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides an application of Scrophularia ningpoensis extract in preventing and controlling foodborne enteritis in carnivorous fish, solving the problem of whether Scrophularia ningpoensis is effective as a feed additive in treating foodborne enteritis in carnivorous fish.

[0008] To achieve the above objectives, the present invention is implemented by the following technical scheme: a method for preparing a Scrophularia ningpoensis extract, comprising the following steps:

[0009] S1. Using dried root of Scrophularia ningpoensis as raw material, crushing and sieving it;

[0010] S2, add 85%-95% ethanol solution at a ratio of 3 times the mass of Scrophularia;

[0011] S3, extraction under reflux conditions 3 times, 4 hours each time;

[0012] S4, combining the extracts, recovering the solvent, and obtaining the Scrophularia ningpoensis extract.

[0013] Preferably, in step S1, the particle size of the dried root of Scrophularia ningpoensis is fine powder that passes through a 100-mesh sieve.

[0014] Preferably, the temperature of the reflux extraction in step S3 is 75°C-90°C.

[0015] Preferably, the extract after reflux extraction in step S3 is vacuum concentrated at a concentration temperature of 50°C-60°C.

[0016] Disclosed is an application of a Scrophularia ningpoensis extract in the preparation of a feed additive for preventing and controlling foodborne enteritis in carnivorous fish. The feed additive contains the Scrophularia ningpoensis extract, and the Scrophularia ningpoensis extract is prepared by a method for preparing the Scrophularia ningpoensis extract.

[0017] Preferably, the added amount of the Scrophularia ningpoensis extract in the feed additive is 0.1%-0.4% of the total weight of the feed.

[0018] Preferably, the feed additive is suitable for fish of the order Perciformes, Salmoniformes or Flatfish, including but not limited to largemouth bass, large yellow croaker, small yellow croaker, grouper, rainbow trout, Atlantic salmon, turbot and oval flounder.

[0019] Preferably, the feed additive is suitable for preventing and controlling non-bacterial enteritis caused by plant protein anti-nutritional factors, and the plant protein anti-nutritional factors include soybean meal, soybean saponin and soybean anti-nutritional factors.

[0020] A use of a Scrophularia ningpoensis extract in the preparation of a drug for preventing and controlling foodborne enteritis in carnivorous fish. The Scrophularia ningpoensis extract is prepared by a method for preparing the Scrophularia ningpoensis extract.

[0021] Preferably, the drug is an oral preparation, and the dosage of the Scrophularia ningpoensis extract is 2‰-4‰.

[0022] The present invention provides the use of Scrophularia ningpoensis extract in preventing and controlling food-borne enteritis in carnivorous fish. It has the following beneficial effects:

[0023] The present invention has found through experiments that 2-4 μg / mL of Scrophularia extract can significantly inhibit LPS-induced inflammation of Caco2 cells and is non-toxic to cells. 2-4 μg / mL of Scrophularia extract can significantly reduce soybean saponin-induced food-borne enteritis in zebrafish, including reducing the transcription levels of pro-inflammatory factors I L1β and I L8 in the intestine, while upregulating the transcription level of anti-inflammatory factor I L10. Under the condition of 5‰ soybean saponin induction, adding Scrophularia extract can effectively improve the symptoms of enteritis of largemouth seabass, increase the weight gain rate of largemouth seabass, improve the antioxidant capacity of largemouth seabass intestines, and improve the intestinal tissue structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the method steps of the present invention;

[0025] Figure 2 Schematic diagram of the contents of inflammatory cytokines and polarization markers in the cell supernatant;

[0026] Figure 3 Schematic diagram of the cell activity of Caco2 after pretreatment with different concentrations of Scrophularia ningpoensis extracts;

[0027] Figure 4Schematic diagram of the mRNA levels of inflammatory cytokines in the intestine of zebrafish induced by saponin;

[0028] Figure 5 This is the appearance morphology of largemouth bass;

[0029] Figure 6 This is a section of the intestinal tissue of largemouth bass. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. 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.

[0031] Example 1: Preparation of in vitro active experimental drugs

[0032] Please refer to the attached Figure 1 , Scrophulariaceae extract: weigh an appropriate amount of Scrophulariaceae, crush it, and pass it through a 100-mesh sieve; add 95v / v% ethanol equivalent to 3 times its weight, reflux extraction 3 times, each time for 4 hours, combine the extracts, and recover the solvent by rotary evaporation to obtain Scrophulariaceae extract. When used, dilute it with dimethyl sulfoxide to the use concentration.

[0033] Soybean saponin: The puffed soybean meal was extracted with 80 v / v% ethanol by hot reflux. The solvent was recovered after filtration until there was no alcohol taste. After dilution with water, it was adsorbed using D101 macroporous resin and eluted with water and alcohol respectively. After the solvent was recovered, it was freeze-dried and the content of soybean saponin was determined.

[0034] Example 2: Establishment of Caco2 cell inflammation model and drug activity experiment

[0035] 1. Cell Culture

[0036] Caco2 cells were cultured in a 37°C and 5% CO2 incubator with DMEM medium plus 10% fetal bovine serum and 100U / mL penicillin-streptomycin. Cell passage was performed at a ratio of 1:3. Caco2 cells were made into a cell suspension and inoculated in a 6-well plate and cultured in an incubator. After growing to full fusion, they were divided into 5 groups, namely the control group (ZC), the inflammatory model group (MX), the drug group 1 (XS1), the drug group 2 (XS2), and the drug group 4 (XS3). The control group was added with blank DMEM complete medium, the inflammatory model group was added with DMEM complete medium containing 2μg / mL LPS, and the drug groups 1, 2, and 4 were added with DMEM complete medium containing 1‰, 2‰, and 4‰ Scrophularia extract, respectively.

[0037] 2.ELISA to detect inflammatory cytokine concentrations

[0038] The cells in the ZC group, MX group, XS1 group, XS2 group, and XS3 group were cultured for 48 hours and the supernatants were obtained. According to the instructions of the ELISA kit, the A450 of each group was detected immediately after the color development was stopped, and the standard curves were drawn respectively. According to the obtained regression equations and the dilution multiples, the concentrations of IL17, Arg-1, and MCP-1 were calculated.

[0039] The results are as follows Figure 2 As shown, the levels of IL17, Arg-1 and MCP-1 showed the order of MX group > XS1 group > XS2 group > XS3 group > ZC group.

[0040] 3. Cell Viability Detection

[0041] Caco2 cells in the logarithmic growth phase were inoculated into 96-well plates, and a calibration group, a blank control group (D′, 0 μg / mL), and groups with different concentrations of Scrophularia ningpoensis extracts (XS1, XS2, XS3, i.e., 1, 2, and 4 μg / mL) were set up.

[0042] The correction group contained only an equal volume of DMEM without FBS, the blank control group contained cells and DMEM without FBS, and the Scrophulariaceae extract group contained cells and different concentrations of Scrophulariaceae extracts. There were 3 samples in each group, and 3 replicate wells were set for each sample. The samples were cultured in a constant temperature incubator (37°C, 5% CO2) for 24 hours.

[0043] 10% CCK-8 solution was added to each well 2h before detection, incubated in dark for 2h, and the absorbance at 450nm was detected by microplate reader. The experimental results were expressed as cell activity, cell activity (%) = (A450 of Scrophularia extract group-A450 of calibration group) / (A450 of blank control group-A450 of calibration group) × 100%.

[0044] The results are as follows Figure 3 There was no significant difference in cell activity among the blank control group, XS1 group, XS2 group and XS3 group, indicating that 1-4 μg / mL of Scrophularia ningpoensis extract had no toxicity to cells.

[0045] Example 3: Evaluation of the anti-inflammatory activity of Scrophularia ningpoensis extract in zebrafish

[0046] 1. Zebrafish husbandry

[0047] Soybean saponin was added to the diet of wild zebrafish (AB type, National Zebrafish Resource Center) at a mass ratio of 5‰ to induce enteritis in zebrafish to obtain a non-bacterial inflammation model group; the positive drug dexamethasone (DEX) group added DEX to the feed of the inflammation model group; the drug group added the Scrophularia extract obtained in Example 1 to the feed of the model group according to the concentration in Table 1 to prepare the experimental feed. Before the experiment, the zebrafish were temporarily raised for 3 days, and then randomly divided into 8 groups, each with 3 replicates, each with 10 fish, and fed twice a day (8:00, 17:00) to the apparent full state. The experiment was carried out in a zebrafish breeding system, and the breeding experiment period was 4 weeks.

[0048] Table 1 Feed and drug ratios for evaluation of anti-inflammatory activity in zebrafish

[0049]

[0050] Fish meal group (FM): zebrafish whole fish meal diet ( Small fish feed).

[0051] Foodborne gastroenteritis model group (SBM): zebrafish whole fish meal diet was used, and 5‰ soybean saponin was added according to the feed mass ratio.

[0052] Positive drug group: zebrafish whole fish meal diet was used, and 5‰ soybean saponin and 0.2‰ DEX (90μg / ml) were added according to the mass ratio.

[0053] Drug group: zebrafish whole fish meal diet was used, and 5‰ soybean saponin was added according to the mass ratio and the corresponding amount of Scrophularia ningpoensis extract was added according to Table 1.

[0054] 2. Sample Collection

[0055] After the breeding experiment, three fish were randomly selected from each group and dissected using sterile dissection tools. The terminal third of the intestinal tissue was cut and rinsed with pre-cooled PBS. After cleaning the mesentery and contents, they were immediately placed in an RNase-free EP tube and immersed in liquid nitrogen, and then placed in a -80°C refrigerator for use.

[0056] 3. Analysis of the mRNA expression levels of pro-inflammatory factors I L1β and IL8 and anti-inflammatory factor I L10 in intestinal tissue;

[0057] Real-time fluorescence quantitative PCR: The total RNA of intestinal tissues of each group was extracted with RNA extraction reagent TRIZOL, and reverse transcribed into cDNA using a kit. Using β-actin gene as an internal reference, the expression levels of IL1β, IL8 and IL10 in mRNA in intestinal tissues of each group were detected by real-time fluorescence quantitative PCR.

[0058] The 2-△△Ct method was used to calculate the transcription levels of IL1β, IL8 and IL10 in the intestine of each group of zebrafish. The calculation results were analyzed by one-way analysis of variance using IBM SPSS Statistics 26.0 software to analyze the significance level (p<0.05 indicated a significant difference).

[0059] 4. Test results

[0060] Real-time fluorescence quantitative PCR results Figure 4 As shown. The results showed that compared with the SBM group, among the three groups of different addition amounts of Scrophularia extract, the XS1 group, XS2 group and XS3 group could significantly reduce the transcription levels of pro-inflammatory factors I L1β and IL8 in the zebrafish intestine, among which the XS2 group was the most obvious; the Scrophularia extract added at 2‰ and 4‰ could significantly increase the expression level of anti-inflammatory factor I L10 in the zebrafish intestine, among which the XS2 group was particularly obvious. The experiment found that the Scrophularia extract added at 2-4‰ could not only significantly downregulate the expression level of pro-inflammatory factors, but also upregulate the expression of anti-inflammatory factors, indicating that this addition range has the most significant anti-inflammatory activity, and its application effect can be further explored.

[0061] Example 4 Comparison of growth performance of largemouth bass after using Scrophularia ningpoensis extract as feed additive

[0062] Preparation of Scrophularia ningpoensis extract: Same as Example 1.

[0063] Trial Groups:

[0064] The experiment set up a fish meal group (FM, using commercial feed for largemouth bass), an inflammation model group (SBM, 5‰ soybean saponin was added to the FM group), and a drug group (XS, 2‰ Scrophularia ningpoensis extract was added to SBM). The specific preparations are shown in Table 2.

[0065] Table 2 Evaluation of feed and drug ratios for largemouth bass

[0066]

[0067] Fish meal group (FM): largemouth bass = all fish meal diet.

[0068] Foodborne gastroenteritis model group (SBM): Largemouth bass were fed a whole fish meal diet and 5‰ soybean saponin was added according to the feed mass ratio.

[0069] Drug group: The largemouth bass whole fish meal diet was used, and 5‰ soybean saponin was added according to the mass ratio and the corresponding amount of Scrophularia ningpoensis extract was added according to Table 2.

[0070] Breeding experiment:

[0071] 270 largemouth bass with an average weight of about 21g were selected and kept for one week. Before the experiment, they were anesthetized with MS-222 (ethyl m-aminobenzoate methanesulfonate, Sigma-Aldrich imported and packaged) and then randomly divided into 3 groups, namely FM group, SBM group and XS group, with three replicates in each group and 30 fish in each replicate. The initial weight and initial body length were measured. After the experiment started, the corresponding feeds were fed twice a day (8:00 and 17:00) to the apparent fullness level. Air stones were used for continuous aeration to maintain sufficient dissolved oxygen concentration. The average temperature was 31℃.

[0072] Fresh seawater was replaced every day, with 30% of the water replaced in the early stage of the experiment and 100% replaced in the later stage of the experiment. The breeding experiment lasted for 8 weeks. After the experiment, feeding was stopped. After 24 hours, the fish were anesthetized with MS-222, and their final body weight and length were measured. The weight gain rate (WGR), specific growth rate (SGR) and survival rate (SR) of grouper were calculated based on the measured data.

[0073] The calculation formula is as follows:

[0074] Survival rate = final number / initial number × 100%

[0075] Weight gain rate = (final weight - initial weight) / initial weight × 100%

[0076] Specific growth rate = (ln end weight - ln initial weight) / number of feeding days × 100%

[0077] The growth performance results are shown in Table 3. Figure 5 As shown, from top to bottom are (A), (B), and (C), wherein (A) is a group fed with a whole fish meal feed; (B) is a group fed with a whole fish meal feed + 5‰ soybean saponin feed; (C) is a group fed with a whole fish meal feed + 5‰ soybean saponin + 0.2% Scrophularia ningpoensis extract feed.

[0078] Table 3 Growth performance of largemouth bass in FM group, SBM group and XS group

[0079]

[0080]

[0081] Different superscript letters in the same row indicate significant differences (p<0.05).

[0082] As shown in the results of Table 3, there was no death in the largemouth bass in the fish meal group, soybean meal group and Scrophularia group, and the survival rate was 100%. The average weight gain rate and specific growth rate of the soybean meal group were significantly lower than those of the fish meal group and Scrophularia group. The applicant found through experiments that the addition of 5‰ soybean saponin to the whole fish meal feed significantly affected the growth performance of largemouth bass, and the addition of Scrophularia at the same time as 5‰ soybean saponin significantly improved the growth performance of largemouth bass, and the results were close to those of the fish meal group. It can be seen that Scrophularia has a significant effect on improving food-borne enteritis in largemouth bass, and the effect is long-lasting and there is no recurrence.

[0083] Example 5 Comparison of intestinal antioxidant capacity of various groups of largemouth bass

[0084] Preparation of Scrophularia ningpoensis extract: Same as Example 1.

[0085] Experimental grouping and breeding experiment: Same as Example 4.

[0086] Sample collection and test: After the 8-week experiment, 3 fish were randomly selected from each group, anesthetized with MS-222, and the intestines were collected aseptically. The intestinal superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) were determined using kits, including superoxide dismutase (SOD) (A001-2-2), catalase (CAT) (A007-2-1) and malondialdehyde (MDA) (A003-1-2) levels. The detection procedures were strictly carried out in accordance with the operating manual of each kit, and the results are shown in Table 4.

[0087] Table 4 Intestinal enzyme activities in FM group, SBM group and XS group

[0088]

[0089] Different superscript letters in the same row indicate significant differences (p<0.05).

[0090] As shown in the results of Table 5, the superoxide dismutase and catalase activities in the intestine of the SBM group were significantly lower than those in the FM group and the XS group, while the malondialdehyde activity was significantly higher than those in the FM group and the XS group, and there was no significant difference in superoxide dismutase activity and malondialdehyde activity between the FM group and the XS group. The applicant found through experiments that soybean saponin-induced largemouth bass food-borne enteritis can reduce the antioxidant capacity of its intestine, and the Scrophularia extract can significantly improve the problem of reduced antioxidant capacity of the largemouth bass intestine caused by food-borne enteritis, thereby preventing and treating food-borne enteritis.

[0091] Example 6 Observation of intestinal tissue structure of each group of largemouth bass

[0092] The preparation method, use method and breeding experiment of Scrophularia ningpoensis extract are the same as those in Example 4. After the experiment, 3 fish were randomly selected from each group, and the intestines were collected aseptically and placed in 4% paraformaldehyde universal tissue fixative to prepare intestinal tissue sections. The fixed intestinal tissue was dehydrated with graded ethanol (concentration 70-100%) and transparentized with xylene. After embedding, slicing, baking, and dewaxing, it was stained with hematoxylin and eosin in turn. Finally, after dehydration, transparency, sealing and drying, it was observed under a microscope. The results are as follows Figure 6 As shown, Figure 6 (A) is the group fed with whole fish meal feed; (B) is the group fed with whole fish meal feed + 5‰ soybean saponin feed; (C) is the group fed with whole fish meal feed + 5‰ soybean saponin + 0.2% Scrophularia ningpoensis extract feed; a: intestinal villi. Scale bar: 100 μm.

[0093] like Figure 6 The results showed that the intestinal villi of the SBM group were significantly shorter than those of the FM group, the infiltration of inflammatory cells increased significantly, the lamina propria became wider, and the number of goblet cells increased significantly. Compared with the SBM group, the infiltration of inflammatory cells in the XS group was significantly reduced, the lamina propria was significantly narrower, and the number of goblet cells was significantly reduced. The applicant further determined through experiments that soybean saponins can induce food-borne enteritis in largemouth bass, and Scrophularia extract can effectively improve and repair intestinal structural damage caused by food-borne enteritis.

[0094] 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 method for preparing a Scrophularia ningpoensis extract, characterized in that: The following steps are involved: S1. Using dried root of Scrophularia ningpoensis as raw material, crushing and sieving it; S2, add 85%-95% ethanol solution at a ratio of 3 times the mass of Scrophularia; S3, extraction under reflux conditions 3 times, 4 hours each time; S4, combining the extracts, recovering the solvent, and obtaining the Scrophularia ningpoensis extract.

2. The method for preparing a Scrophularia ningpoensis extract according to claim 1, characterized in that: In the step S1, the particle size of the dried root of Scrophularia ningpoensis is fine powder that can pass through a 100-mesh sieve.

3. The method for preparing a Scrophularia ningpoensis extract according to claim 1, characterized in that: The temperature of the reflux extraction in the step S3 is 75°C-90°C.

4. The method for preparing a Scrophularia ningpoensis extract according to claim 1, characterized in that: The extract after reflux extraction in step S3 is vacuum concentrated at a concentration temperature of 50°C-60°C.

5. Use of a Scrophularia ningpoensis extract in the preparation of a feed additive for preventing and controlling foodborne enteritis in carnivorous fish, characterized in that: The feed additive contains a Scrophulariaceae extract, which is prepared by the method for preparing a Scrophulariaceae extract according to any one of claims 1 to 4.

6. Use of a Scrophularia ningpoensis extract according to claim 5 in the preparation of a feed additive for preventing and controlling foodborne enteritis in carnivorous fish, characterized in that: The added amount of the Scrophularia ningpoensis extract in the feed additive is 0.1%-0.4% of the total weight of the feed.

7. Use of a Scrophularia ningpoensis extract according to claim 5 in the preparation of a feed additive for preventing and controlling foodborne enteritis in carnivorous fish, characterized in that: The feed additive is suitable for fish of the order Perciformes, Salmoniformes or Plaiceae, including but not limited to largemouth bass, large yellow croaker, small yellow croaker, grouper, rainbow trout, Atlantic salmon, turbot and oval flounder.

8. The use of a Scrophularia ningpoensis extract according to claim 5 in the preparation of a feed additive for preventing and controlling foodborne enteritis in carnivorous fish, characterized in that: The feed additive is suitable for preventing and controlling non-bacterial enteritis caused by plant protein anti-nutritional factors, and the plant protein anti-nutritional factors include soybean meal, soybean saponin and soybean anti-nutritional factors.

9. Use of a Scrophularia ningpoensis extract in the preparation of a drug for preventing and controlling foodborne enteritis in carnivorous fish, characterized in that: The Scrophulariaceae extract is prepared by the method for preparing a Scrophulariaceae extract according to any one of claims 1 to 4.

10. Use of a Scrophularia ningpoensis extract according to claim 9 in the preparation of a drug for preventing and treating foodborne enteritis in carnivorous fish, characterized in that: The medicine is an oral preparation, and the dosage of the Scrophularia ningpoensis extract is 2‰-4‰.

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