Anguilla japonica feed composition using fermented pig blood product

Abstract

The present invention provides an Anguilla japonica feed composition using a fermented pig blood product, the composition having the effects of promoting the growth of Anguilla japonica, enhancing health, and enhancing feed efficiency. The composition of the present invention comprises a fermented product obtained by inoculating a Lactobacillus johnsonii strain into pig blood and culturing same.

Description

Feed composition for farmed eel using fermented pig blood

[0001] The present invention relates to a feed composition for farmed eel using fermented pig blood.

[0002] Due to improved living standards and rising incomes, meat consumption is increasing, and the number of cattle and pigs slaughtered domestically is also increasing. Until the early 2000s, blood byproducts were so popular that even blood was sold through auctions. However, with changing food cultures, approximately half of this blood is now discarded, unable to be recycled.

[0003] Blood is mostly composed of protein-based organic substances and decomposes rapidly, producing a foul odor. In general, 5 tons of water are required to process 1 ton of animal blood. As of 2015, the processing cost per ton was 410,000 won, and it is reported that approximately 25 billion won is spent annually in processing costs in Korea.

[0004] Therefore, hygienically collecting, sorting, and recycling slaughter blood would be desirable, as it would reduce wastewater treatment costs and environmental pollution. This is particularly true given the ban on ocean dumping of slaughter blood, which came into effect in 2013 under the London Convention, making recycling technology even more essential.

[0005] As can be seen in Korean Patent No. 1012648760000 entitled “Method for producing liquid fertilizer using animal blood” and Korean Patent No. 1011003290000 entitled “Method for producing amino acids using livestock blood and organic fertilizer using the same,” research has been conducted recently to recycle slaughter blood as feed or fertilizer.

[0006] The present invention discloses a technology for recycling fermented pig slaughter blood as feed for farmed eels.

[0007] The purpose of the present invention is to provide a feed composition for farmed eel using fermented pig blood.

[0008] Other or specific purposes of the present invention will be presented below.

[0009] The present invention relates, in one aspect, to a feed composition for farmed eels (Anguilla japonica, Japanese Eel) containing fermented pig blood. The farmed eel feed composition of the present invention has growth promotion effects (or uses), feed efficiency enhancement effects (or uses), and health promotion effects (or uses) of farmed eels, as confirmed in the examples below. Here, feed efficiency is a concept opposite to feed conversion ratio, and a higher feed efficiency means a higher weight gain effect even when the same amount of feed is fed to farmed eels. In addition, the health promotion effects here refer to at least one of liver health promotion effects (i.e., liver function enhancement effects), immunity enhancement effects, antioxidant enhancement effects, digestive enhancement effects, intestinal function enhancement effects, and inflammation response inhibition effects of eels. These health promotion effects can reduce the mortality rate of eels (increase the survival rate), which can ultimately bring about economic benefits to farm owners.

[0010] In the present invention, the fermented pig blood refers to a fermented pig blood by Lactobacillus johnsonii, that is, a fermented pig blood obtained by inoculating Lactobacillus johnsonii into pig blood and culturing it.

[0011] In the present invention, since the main component of pig blood is protein, it may be blood to which an anticoagulant has been added to prevent blood coagulation during storage and facilitate fermentation. The anticoagulant may be any one known in the art, such as sodium citrate, acid citrate dextrose (ACD), citrate phosphate dextrose (CPD), CPDA-1 (CPD adenine-1), etc., and may be added and used in the range of 2 to 15% (v / v).

[0012] In addition, in the present invention, it is preferable that the pig blood be hydrolyzed with a proteolytic enzyme before fermentation. This hydrolysis is to prevent blood coagulation and facilitate fermentation, and can be performed for a sufficient period of time using any proteolytic enzyme under its optimal activity conditions. Proteolytic enzymes that can be used include pepsin, trypsin, papain, bromelain, Neutrase™, Protamex™, Alcalase™, Provia™, etc., and the optimal temperature conditions for the activity of the corresponding enzymes may be, for example, 37°C for pepsin, 25°C for trypsin, 45°C for Protamex™, 50°C for Neutrase and Protamex, and 50°C for Alcalase, and the hydrolysis time may be in the range of 24 to 72 hours. The hydrolytic enzyme will typically be added and used in the range of 1 to 3% (w / v) of the pig blood.

[0013] In addition, in the present invention, when pig blood or pig blood is hydrolyzed, a carbon source may be added to the hydrolyzate to facilitate fermentation by the inoculated strain. Any carbon source known in the art may be used as the carbon source, such as oligosaccharides, lactose, glucose, fructose, sucrose, molasses, dextrose, etc. Depending on the fermentation time, degree of fermentation, etc., the carbon source may be added in the range of 0.1% (w / v) to 10% (w / v) of the hydrolyzate.

[0014] In addition, in the present invention, the culture temperature may range from 15°C to 50°C. Considering the culture speed, it is preferably 30°C or higher. In particular, it may range from 30°C to 50°C.

[0015] In addition, in the invention, the incubation period, i.e., the incubation period of the fermenting strain after inoculation, is preferably at least three days. This is because, as the examples below demonstrate, a fermentation period of at least three days allows the fermenting strain to reach a stable state and maintain a constant pH of 4.0. Blood samples, primarily composed of protein, deteriorate rapidly even if left at room temperature for 1-2 days. However, a pH of 4.0 allows for long-term storage at room temperature for approximately 12 months.

[0016] The fermented pig blood product of the present invention can be used in the form of a concentrated liquid or powder obtained by lyophilizing the cultured original solution itself, or by condensing the cultured original solution through freeze-drying, decompression concentration, vacuum drying, spray drying, hot air drying, etc. When using a concentrated, desired useful component of the fermented product, the fermented product can be used in the form of an extract. The extract refers to an extract obtained by leaching the fermented product (culture solution or concentrate thereof) using water or an organic solvent (e.g., lower alcohols having 1 to 4 carbon atoms such as methanol, ethanol, butanol, methylene chloride, ethylene, acetone, hexane, ether, chloroform, ethyl acetate, butyl acetate, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), 1,3-butylene glycol, propylene glycol) or a mixed solvent thereof, an extract obtained using a supercritical extraction solvent such as carbon dioxide or pentane, or a fraction obtained by fractionating the extract, and the extraction method may be any method such as cold maceration, reflux, heating, ultrasonic radiation, or supercritical extraction, taking into account the polarity, degree of extraction, and degree of preservation of the extract material. The extract may be used in the form of a liquid or powder obtained by concentrating the crude extract itself, or by freeze-drying, vacuum concentration, vacuum drying, spray drying, hot air drying, etc.

[0017] The fermented pig blood product of the present invention may also be used in a mixed form with one or more carriers, such as fish meal or soybean powder. When used in this mixed form, the fermented blood coats the surface of the fish meal or soybean powder particles, and when added to a main feed at a low concentration of 1 to 2 wt%, it has the effect of facilitating dispersion. Here, fish meal refers to a product obtained by steaming all or part of a fish, pressing to remove the liquid, drying the solid portion, and then grinding it.

[0018] The feed composition of the present invention can be manufactured by including, in addition to the fermented pig blood, ingredients commonly used in farmed eel feed for the purposes of promoting eel growth, promoting digestion, enhancing feed efficiency, enhancing immunity, and enhancing disease resistance. Such ingredients include plant-based ingredients, animal-based ingredients, and mineral-based ingredients.

[0019] The above plant-based ingredients include grains such as oats, buckwheat, wheat, barley, sorghum, rice, corn, millet, barley, and rye; bran (grain by-products) such as millet hull, oat bran, soybean hull, wheat bran (wheat hull), barley bran, sorghum bran, rice bran, corn hull, coix seed hull, and barley bran; offal such as mustard meal, guar meal, oat meal, soybean meal, perilla seed meal, brewer's meal, cottonseed meal, wheat germ meal, palm meal, olive meal, and starch meal; food processing by-products such as potatoes, sweet potatoes, and Jerusalem artichokes, potato processing by-products, fruit processing by-products, and vegetable processing by-products; algae such as galrae gombo, galpae, kelp, laver, burdock, and kelp; microalgae such as Nannochloropsis, Dunaliella, and Spirulina; fibers such as dalis grass, ladino clover, red top, and barley sprouts; soybean oil, hemp seed oil; Examples include oils such as cottonseed oil and rice bran oil, starches such as cereal starch and paper starch, beans such as soybeans and lentils, fruits such as mangoes, bananas, pears and apples, vegetables such as eggplants, carrots, radishes, sugar beets and samchae, and mushrooms such as shiitake mushrooms, oyster mushrooms and reishi mushrooms.

[0020] These plant-based ingredients may be included in the feed composition of the present invention in appropriate amounts depending on their intended use, such as growth promotion, digestion promotion, and feed efficiency enhancement. Typically, they will be included in an amount ranging from about 3 to about 80 weight percent, depending on the type of ingredient, intended use, etc.

[0021] Animal ingredients include proteins such as dried poultry by-products, dried fish, crab meal, egg powder, whelk meal, and fish meal; inorganic ingredients such as bone meal, bone ash, fish bone meal, and shell meal; fats such as chicken fat, animal edible residue, lard, and beef tallow; insects such as mealworm larvae, dried crickets, and dried locusts; plankton such as rotifers, mysis shrimp, and daphnia; and dairy processing by-products such as lactose, whole milk powder, cheese, and skimmed milk powder. These ingredients may also be included in the feed composition of the present invention in an amount of about 3 to about 80 wt% depending on the type of ingredient, purpose of use, etc.

[0022] Mineral ingredients include limestone powder, calcium carbonate, calcium sulfate, ferric citrate, sodium molybdate, ammonium molybdate, sodium selenite, sodium selenite, chromium chloride, potassium iodate, calcium iodate, potassium iodide, manganese carbonate, copper sulfate, manganese sulfate, zinc sulfate, etc., and these mineral ingredients will be included in trace amounts (0.0001 to 5 wt %) in the feed composition of the present invention.

[0023] In addition to the plant-based ingredients, animal-based ingredients, and mineral ingredients, the feed composition of the present invention may further include a binder, a preservative, a vitamin, an enzyme, a microbial agent, a flavoring agent, etc. for the purposes of enhancing immunity, enhancing feed preservation, promoting uniform mixing of feed ingredients, and facilitating formulation, and these ingredients will be included in the feed composition of the present invention in an appropriate amount (0.0001 wt% to 10 wt%) depending on the intended use.

[0024] Examples of the above binders include natural binders such as guar gum, cellulose, and gelatin, and synthetic binders such as sodium alginate, ammonium alginate, and potassium alginate.

[0025] In addition, the above preservatives may include acidulants such as malic acid, tartaric acid, formic acid, and citric acid, anticoagulants such as calcium stearate and tin chloride, antioxidants such as resveratrol, gallic acid, and vitamin E, and antifungal agents such as propionic acid and sodium propionate.

[0026] Also, examples of the above vitamins include L-carnitine, niacin, nicotinamide, biotin (vitamin H), vitamin A, thiamine naphthalene-1,5-disulfonate, and thiamine lauryl sulfate.

[0027] In addition, examples of the above enzymes include scrapiecoamylase, lactase, cellulase, rapamycin, phytase, and protease.

[0028] In addition, examples of the above-mentioned microorganisms include lactic acid bacteria such as Lactobacillus lactis, Lactobacillus rhamnosus, Lactobacillus bulgaricus, and Lactobacillus brevis, fungi such as Aspergillus oryzae, and yeasts such as Saccharomyces cerviciae.

[0029] In addition, examples of the above flavoring agents include natural flavoring substances, synthetic flavoring substances, sweeteners such as licorice and fructose.

[0030] The feed composition of the present invention can be formulated in the form of a liquid (particularly in the form of a pig blood culture solution or concentrate thereof), powder, granule, pill or pellet.

[0031] In the feed composition of the present invention, the fermented pig blood product, which is an effective ingredient, may be included in an amount ranging from 0.1 wt% to 10 wt% based on the total weight of the feed composition in order to exhibit the intended growth promotion effect or health promotion effect.

[0032] In another aspect, the present invention relates to a method for promoting growth or improving health of farmed eels, comprising the step of feeding the fermented pig blood product described above to farmed eels.

[0033] In the method of the present invention, feeding of fermented pig blood can be accomplished by adding the fermented pig blood to feed or mixing it into a breeding tank.

[0034] In another aspect, the present invention relates to an antibacterial composition comprising the fermented pig blood described above as an active ingredient.

[0035] The examples below demonstrate that fermented porcine blood has antibacterial activity against E. coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella typhimurium.

[0036] The antibacterial composition of the present invention may contain the fermented product, which is an effective ingredient, in an amount of 0.0001 wt% to 20 wt%, preferably 0.1 wt% to 10 wt%, based on the total weight of the composition, depending on the product form in which the antibacterial composition of the present invention is embodied.

[0037] In a specific embodiment, the antibacterial composition of the present invention can be considered as a non-medical composition.

[0038] When the composition of the present invention is manufactured as a pharmaceutical composition, the composition of the present invention may be manufactured by including a dispersing agent and a carrier in addition to the active ingredient.

[0039] As such dispersants, water, alcohols (e.g., methyl alcohol, ethyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, glycerin, etc.), ketones (e.g., acetone, methyl ethyl ketone, etc.), ethers (e.g., dioxane, tetrahydrofuran, cellosolve, diethylene glycol dimethyl ether, etc.), aliphatic hydrocarbons (e.g., hexane, kerosene, etc.), aromatic hydrocarbons (e.g., benzene, toluene, xylene, naphthalene, methyl naphthalene, etc.), halogenated hydrocarbons (e.g., chloroform, carbon tetrachloride, etc.), acid amides (e.g., dimethyl formamide, etc.), esters (e.g., methyl acetate ester, ethyl acetate ester, butyl acetate ester, fatty acid glycerin ester, etc.), nitroles (e.g., acetonitrile, etc.), surfactants (higher alcohol sulfate esters, alkyl Examples thereof include sulfonic acid, alkyl allyl sulfonic acid, quaternary ammonium salt, oxyalkyl amine, fatty acid ester, polyalkylene oxide compound, anhydrosorbitol compound, etc., and the dispersant may be included in the antibacterial composition of the present invention alone or as a mixture of two or more thereof.

[0040] Examples of carriers include clay (e.g., kaolin, bentonite, acid clay, etc.), talc (e.g., talc powder, pyrophyllite powder, etc.), silica (e.g., diatomaceous earth, silicic anhydride, mica powder, etc.), alumina, sulfur powder, activated carbon, etc., and these carriers may be included in the antibacterial composition of the present invention alone or as a mixture of two or more thereof.

[0041] When the composition of the present invention is manufactured as an over-the-counter drug composition, it may be classified into any product category as long as it complies with the applicable laws and regulations at the time of manufacturing and distribution in terms of legal and functional classification. Specifically, it may be manufactured by absorbing or applying it to sanitary napkins, masks, mouthwashes, toothpaste, pads, wet tissues, sterile cotton swabs, sterile gloves, etc., or when manufactured as an over-the-counter drug for animals, it may be manufactured as a disinfectant, sterilizer, detergent, etc.

[0042] As described above, the present invention can provide a feed composition for farmed eels using fermented pig blood. When fed to farmed eels, the feed composition of the present invention has growth promotion effects (or uses), feed efficiency enhancement effects (or uses), and health promotion effects (or uses) in the farmed eels.

[0043] Figure 1 shows the results of the evaluation of growth and feed conversion rate in the eel feeding test.

[0044] Figure 2 shows the evaluation results for AST and ALT, which are hematological indicators of liver health, in an eel feeding test.

[0045] Figure 3 shows the results of an evaluation of the blood concentrations of total antibodies and lysozyme, which are blood indicators of non-specific innate immunity, in an eel feeding test.

[0046] Figure 4 shows the results of an evaluation of the concentration or activity of SOD, GPx, and CAT, which are blood indicators of antioxidant power, in an eel feeding test.

[0047] Figure 5 shows the results of the evaluation of trypsin, chymotrypsin, and lipase activities, which are indicators of digestive power, in an eel feeding test.

[0048] Figure 6 shows the evaluation results for villi length and goblet cells, which are intestinal health indicators, in an eel feeding test.

[0049] Figure 7 shows the inflammatory cytokines TNF-α, IL-1β, and transcription factor NF-κB, which are liver inflammation indicators in an eel feeding test. These are the evaluation results for STAT1.

[0050] The present invention will be described below with reference to examples. However, the scope of the present invention is not limited to these examples.

[0051] <Example 1> Production of fermented pig blood

[0052] 1. Production of fermented pig blood

[0053] Pig blood was purchased from a slaughterhouse in Jeju Island, and the blood samples were stored frozen with 3% (v / v) of 4% sodium citrate solution, an anticoagulant.

[0054] Frozen blood samples were thawed at room temperature, and 1.5% (w / v) of the protein hydrolase (Provia™, Novozyme, Co.) was added thereto, and hydrolysis was performed for 3 hours with stirring (100 rpm) at 40°C.

[0055] To the blood sample treated with the above proteolytic enzyme, 8% (w / v) of sugar was added as a carbon source and mixed, and then 6% (v / v) of Lactobacillus johnsonii JERA01 (Accession No.: KCTC14420BP, Deposit Date: December 28, 2020) was added as a carbon source and inoculated, stirred at 50 rpm, and cultured at 30°C to produce a fermented pig blood product.

[0056] The Lactobacillus johnsonii JERA01 culture solution above was prepared by culturing in MRS Broth medium at 30℃ for 4 days (number of bacteria: 3 × 10 8 cells / ml).

[0057] 2. Characteristics of fermented pig products

[0058] The pH of the fermented product was pH 5.5 on the first day of fermentation, pH 4.5 on the second day, and pH 4.2 on the third day. Also, on the first day of fermentation, the organic acid odor was weak and the blood odor was relatively strong, but from the second day of fermentation, the organic acid odor began to be strong, and on the third day, various fermentation odors including the organic acid odor were strong and the blood odor was almost absent. The color turned dark brown from the third day of fermentation.

[0059] The fermented product (20 Brix) was concentrated under reduced pressure to increase stability and nutritional value, and 30 Brix and 40 Brix concentrates were produced.

[0060] The general component analysis results of the above 30 Brix, 40 Brix concentrates are shown in Table 1 below, the amino acid analysis results are shown in Table 2, and the harmful microorganism analysis results are shown in Table 3. Referring to Tables 1 to 3, heavy metals such as cadmium, arsenic, and lead were not detected, and mercury was detected at 0.26 mg / kg, which is below the hazardous heavy metal standards of lead (20 ppm), arsenic (25 ppm), mercury (1 ppm), and cadmium (50 ppm) stipulated in Appendix 16 of the Ministry of Agriculture, Food and Rural Affairs' Notice on "Standards and Specifications for Feed, etc.", and no harmful microorganisms were detected.

[0061] The concentrate was aged for one month and used in the experiment (pH 4.0).

[0062]

[0063]

[0064]

[0065] <Example 2> Antibacterial activity experiment

[0066] 1. Experimental method

[0067] Antibacterial testing is performed according to the ASTM E149 test method, specifically as follows:

[0068] First, take 1 ml of each sample and mix it in phosphate buffer (pH 7.0), then add each test bacterial culture to it and 2.5 × 10 5 The concentration was adjusted to 100 cfu / ml. The total volume of the phosphate buffer solution containing each sample and test bacteria was adjusted to 50 ml, and the concentration of the injected sample was adjusted to 2% (v / v). 1 ml of each dilution was applied to a film medium for bacterial culture and cultured for 24 hours. Finally, the number of test bacteria in the cultured film medium was measured.

[0069] 2. Experimental Results

[0070] The results of the antibacterial test are shown in Table 4 below.

[0071] Antibacterial test results Classification BLANK Concentrated fermented sample (30 Bx) Concentrated fermented sample (40 Bx) E. coli (Escherichia coli) Initial bacterial count 1.8 x 10 5 1.8x10 5 1.8x10 5 24 hours later 3.1x10 5 <30<30Bacterial reduction rate -99.999.9S.aureus (Staphylococcus aureus)Initial bacterial count 1.8x10 5 1.8x10 5 2.3x10 5 24 hours later 3.0x10 5 4.1x10 2 <30 Bacterial reduction rate - 99.999.9K.pneumoniae (pneumoniae) initial bacterial count 2.1x10 5 2.1x10 5 2.1x10 5 24 hours later 3.2x10 5 <30<30 Bacterial reduction rate -99.999.9 S. typhimurium (Salmonella) initial bacterial count 2.0x10 5 2.0x10 5 2.0x10 5 24 hours later 3.1x10 5 <30<30 Bacterial reduction rate -99.999.9P. aeruginosa (Pseudomonas aeruginosa) Initial bacterial count 2.7x10 5 2.7x10 5 2.7 x 10 5 24 hours later 3.0x10 5 <30<30 Bacterial reduction rate -99.999.9

[0072] * Sample concentration: 2% (v / v) Bacterial reduction rate unit: %

[0073] Bacterial count unit: cell / mL

[0074] Buffer solution: PHOSPHATE BUFFER 50 mL (pH 7.2)

[0075] The results in Table 3 above demonstrate that the fermented blood sample exhibited very high antibacterial activity against all tested bacteria. For reference, the non-fermented blood sample (obtained by hydrolysis with protease after sodium citrate treatment) exhibited no antibacterial activity at all. In fact, it promoted the growth of all of the above-mentioned bacteria and was also visually significantly decomposed (data not shown).

[0076] <Example 3> Eel feeding test

[0077] 1. Experimental method

[0078] 1.1 Test fish breeding method

[0079] The test was conducted by requesting the Jeju National University Marine Science Research Institute.

[0080] Test fish were purchased from Yangmanjang in Sinan County, Jeollanam-do, and transported to the Jeju National University Marine Science Research Institute. To acclimate the eels to the test environment, they were fed commercially available eel paste feed (Chiman, Kopax, a fermented herbal feed) and conditioned.

[0081] During the 12-week feeding test, water temperature, dissolved oxygen, and pH in the test tank were measured daily, and the water temperature was maintained at 30.0 ± 0.2℃, dissolved oxygen at 6.15 ± 0.20 mg / L, and pH at 6.25 ± 0.21. The concentrations of ammonia, nitrite, and nitrate in the test tank were measured once every three weeks, and ammonia was maintained at 0.10 ± 0.03 mg / L, nitrite at 0.41 ± 0.36 mg / L, and nitrate at 31.0 ± 0.89 mg / L.

[0082] Eels (14.00 ± 0.02 g) were randomly distributed into 12 ABS (acrylonitrile butadiene styrene) circular tanks (300 L), 35 per tank, with three replicates.

[0083] Test feed was kneaded with distilled water at 85% of the feed weight before feeding and was fed twice daily (07:00 and 19:00). To determine feed intake, the remaining feed was dried and weighed 1 hour after feeding.

[0084] 1.2 Preparation of test feed

[0085] The main protein source of the control feed (F0) was anchovy fishmeal (content 67%, Fish meal (Anchovy)), and the protein content was set to 53%. As shown in Table 5 below, the three test feeds were set to have 1, 2, and 4% (F1, F2, F4) of the feed contents by replacing anchovy fishmeal with fermented pig blood meal.

[0086] The 40 Brix fermented pig blood product (20 Brix) was concentrated and vacuum-dried to produce a powder, and the powder thus produced was mixed with commercially available feed fish meal and soybeans in a 1:1 weight ratio, and the powder produced by mixing them in a 1:1 weight ratio was used as an experimental additive feed.

[0087]

[0088] 1.3 Measurement of test fish growth, health, etc.

[0089] After the feeding test, feed was stopped for 24 hours prior to measuring the final weight and number of fish. After weight measurement, weight gain (WG), specific growth rate (SGR), survival, feed conversion ratio (FCR), and protein efficiency ratio (PER) were calculated.

[0090] After the final weight measurement, three test fish per tank (nine fish per test group) were randomly selected and anesthetized with a 200 ppm 2-phenoxyethanol (Sigma, St. Louis, USA) solution, and blood was collected from the caudal vein using a syringe. The collected blood was placed in a 1.5 mL eppendorf tube treated with 20 μL of heparin and used. Plasma was separated by centrifugation (4°C, 5,000 rpm, 10 min) in a centrifuge (Micro 17TR, Hanil Science, Gimpo, Korea) and stored frozen (-80°C) until used for analysis of basal health, non-specific immunity, and antioxidant capacity.

[0091] After final weight measurement, three test fish per tank (nine fish per test group) were randomly selected, and their livers and intestines were removed. The livers and intestines were stored frozen (-80°C) until used for digestive enzyme activity measurements and gene expression analysis.

[0092] For whole-body general composition analysis, 3 test fish per tank (9 fish per test group) were randomly selected and stored frozen (-20℃) until analysis.

[0093] To evaluate the health of the test fish, hematological liver health indices, non-specific immune indices, antioxidant indices, digestive enzyme activities of the liver and intestine, and inflammatory cytokine gene expression levels of the liver were analyzed as follows.

[0094] (1) Liver health indicators: Blood concentrations of AST (aspartate aminotransferase) and ALT (alanine aminotransferase) were measured using a blood biochemistry analyzer (CH 100plus; RADIM Company, Firenze, Italy) according to the manufacturer's protocol.

[0095] (2) Non-specific immune indicators: Blood concentrations of lysozyme and total immunoglobulin were measured based on the methods of Quade and Roth (1997), Anderson and Siwicki (1995), and Hultmark et al. (1980).

[0096] (3) Antioxidant activity index: Blood concentrations or activities of MDA (malondialdehyde), SOD (superoxide dismutase), GPx (glutathione peroxidase), and CAT (catalase) were measured using kits such as GPx, DG-SOD400 (DoGenBio, Seoul, Korea) for SOD, DG-CAT400 (DoGenBio) for CAT, and K379-100 (Biovision, Inc., Milpitas, CA, USA) for MDA, according to the protocols of each manufacturer.

[0097] (4) Digestive enzyme activity: The activities of trypsin, chymotrypsin, and lipase extracted from the intestinal tissue pulverized product were measured based on the method of Natalia et al. (2004).

[0098] (5) Inflammatory markers of the liver: Inflammatory cytokines TNF-α, IL-1β and transcription factor NF-κB were measured by ELISA (Endogen, Cambridge, MA). STAT1 was measured using qPCR (quantitative PCR) according to the manufacturer's protocol.

[0099] 2. Experimental Results

[0100] 2.1 Growth, feed demand

[0101] In the experimental group fed with feed containing fermented pig blood (F1 to F4), weight gain increased and feed conversion rate decreased compared to the control group (FO) (Fig. 1).

[0102] 2. Liver health

[0103] AST and ALT, hematological indicators of liver health, decreased in the experimental group compared to the control group (Fig. 2). AST and ALT are enzymes known as indicators of liver function because they are released into the blood when the liver is damaged (Korean J. Food & Nutr. Vol. 25. No. 3, 546–553 (2012)).

[0104] 3. Nonspecific immunity

[0105] Total immunoglobulin and lysozyme, blood markers of nonspecific innate immunity, were elevated in the experimental group compared to the control group (Fig. 3). Lysozyme is known as a representative marker of innate immunity because it hydrolyzes bacterial cell membranes (PLoS Pathog. 2017 Sep; 13(9): e1006512).

[0106] 4. Antioxidant power

[0107] The concentrations and activities of SOD, GPx, and CAT, which are blood indicators of antioxidant power, increased in the experimental group compared to the control group, while the blood concentration of MDA decreased (Fig. 4). SOD, GPx, and CAT are enzymes that remove reactive oxygen species, and MDA is an enzyme that increases due to oxidative stress (J. Food Hyg. Saf. Vol. 30, No. 4, pp. 383-389 (2015)).

[0108] 5. Digestive power

[0109] Trypsin, chymotrypsin, and lipase activities, which are indicators of digestive power, increased in the experimental group compared to the control group (Fig. 5).

[0110] 6. Gut health

[0111] Villi length and the number of goblet cells, indicators of intestinal health, increased in the experimental group compared to the control group (Fig. 6). Goblet cells secrete MUC2 mucin, which plays a crucial role in protecting the intestinal epithelium and maintaining intestinal homeostasis, as well as CLCA1, FCGBP, AGR2, and ZG16, which are components of the intestinal mucosa (Immunol Rev. 2014 Jul; 260(1): 8-20).

[0112] 7. Inhibits inflammation

[0113] TNF-α, IL-1β, NF-κB, which are inflammatory markers of liver tissue STAT1 was reduced in all experimental groups compared to the control group (Figure 7).

[0114] TNF-α and IL-1β are inflammatory cytokines, NF-κB is a transcription factor that regulates the expression of iNOS and COX-2, which induce excessive production of NO and PGs, and STAT1 is an important transcription factor of the inflammatory signal transduction pathway activated by inflammatory cytokines and inflammatory factors (Cytokine 2006, 36(5-6):218-228; J Biol Chem 2004, 279(29):30175-30181).

[0115] The present invention can be used in a feed composition for eels or in eel breeding.

Claims

1. A feed composition for promoting the growth of farmed eels, comprising a fermented product obtained by inoculating and culturing a Lactobacillus johnsonii strain into pig blood.

2. In paragraph 1, The fermented product is a composition characterized in that the fermented product is in the form of a culture solution itself, a concentrated liquid form of the culture solution, a concentrated powder form of the culture solution, an extract form of the culture solution or the concentrate using water or an organic solvent, or a form mixed with at least one carrier selected from fish meal and soybean powder.

3. In paragraph 1, A feed composition for farmed eel, characterized in that the above-mentioned pig blood has an anticoagulant and a proteolytic enzyme added thereto, and the above-mentioned strain is inoculated into the pig blood having the anticoagulant and the proteolytic enzyme added thereto.

4. In paragraph 3, The carbon source is added to the pig blood to which the above protein hydrolyzing enzyme is added at 5 to 7 wt%. A composition characterized in that the above culturing is performed at a temperature range of 30°C to 50°C.

5. A method for promoting the growth of farmed eels, comprising the step of feeding a composition according to any one of claims 1 to 4 to farmed eels.

6. A feed composition for promoting the health of farmed eels, comprising a fermented product obtained by inoculating and culturing a Lactobacillus johnsonii strain into pig blood. A composition characterized in that the above health promotion is one of promotion of liver function, promotion of immunity, promotion of antioxidant power, promotion of digestive power, promotion of intestinal function, and suppression of inflammatory response.

7. A feed composition for increasing the feed efficiency of farmed eel, comprising a fermented product obtained by inoculating and culturing a Lactobacillus johnsonii strain into pig blood.

8. An antibacterial composition comprising a fermented product obtained by inoculating and culturing a Lactobacillus johnsonii strain into pig blood. The composition is characterized in that the above antibacterial agent has antibacterial activity against E. coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella typhimurium.

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