Mucus production promoter, compound feed, and method for producing cultured fish

Abstract

To provide a method capable of easily increasing the production of body surface mucus of cultured fish in order to maintain the health of the cultured fish in a good state or to improve the health of the cultured fish from a bad state to a good state.SOLUTION: To provide a mucus production promoter containing mealworm beetle as an active ingredient, to provide a formula feed containing the mucus production promoter, and to provide a method for producing cultured fish including a step of feeding the formula feed to the cultured fish.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mucus production promoter containing mealworms as an active ingredient, a compound feed containing the mucus production promoter, and a method for producing farmed fish using the compound feed containing the mucus production promoter. [Background technology]

[0002] Insects have attracted attention as a raw material for compound feed for aquaculture. Insects are not only a nutrient source rich in proteins, lipids, and the like, but are also known to improve the health of farmed fish and other animals that consume them. Specific examples include powdered Tenebrionidae beetles used to prevent or reduce stress in captive fish (see Patent Document 1), beetle powder used to treat vibriosis in mollusks and crustaceans (see Patent Document 2), and a stress reliever containing silkworm pupae (see Patent Document 3). Other known insect-derived functional substances include polysaccharides derived from Diptera and Lepidoptera that have immunostimulatory effects (see Patent Documents 4 and 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7293200 [Patent Document 2] Patent No. 7163312 [Patent Document 3] Japanese Patent Application Publication No. 2022-159199 [Patent Document 4] Patent No. 6019505 [Patent Document 5] Patent No. 6240993 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to maintain the health of farmed fish in good condition or to improve their health from poor to good, it is effective to promote the production of mucus on the body surface of farmed fish and enhance their defenses against pathogens and other bacteria that invade from the outside. Therefore, a method for easily increasing the production of mucus on the body surface of farmed fish has been desired.

[0005] As mentioned above, insects are known to have various functions beyond simply being a source of nutrition, but the relationship between insects and the mucus on the surface of farmed fish such as red sea bream and yellowtail was unclear. [Means for solving the problem]

[0006] The present invention was completed by the inventors after they discovered a new use for insects, particularly mealworms. That is, the present invention is a mucus production promoter that contains mealworms as an active ingredient. The mealworms may be defatted mealworms, which may be defatted using a supercritical fluid. The mucus production promoter of the present invention may be a mucus production promoter for fish.

[0007] Another aspect of the present invention is a compound feed containing a mucus production promoter. The compound feed of the present invention may be a compound feed containing 3 to 10% by weight of the mucus production promoter based on the total weight. Still another aspect of the present invention may be a method for producing farmed fish, including a feeding step of feeding farmed fish with a compound feed containing the mucus production promoter. The feeding step may be a feeding step of feeding the compound feed for 1 to 7 months. [Effects of the Invention]

[0008] The mucus production promoter of the present invention can be used to promote the production of mucus on the body surface of fish. The mucus production promoter of the present invention can be orally administered to farmed fish by being contained in a compound feed, and can easily promote the production of mucus in farmed fish. [Brief explanation of the drawings]

[0009] [Figure 1]The average amount of protein recovered from the body surface of red sea bream with an initial body weight of 1,500 g after feeding the formulated feed of the Example or Comparative Example for two months (n=9). Error bars indicate standard error, and an asterisk indicates that the p-value obtained by the t-test was less than 0.05. [Figure 2] Average amount of protein recovered from the body surface of red sea bream (n=15) with an initial fish weight of 1,780 g after feeding the formulated feed of the Example or Comparative Example for 7 months. Error bars indicate standard error. [Figure 3] Average amount of protein recovered from the body surface of yellowtail fry (Mojako) after feeding them the formulated feed of the Examples or Comparative Examples for one month (n=5). Error bars indicate standard error. [Figure 4] Average amount of protein recovered from the body surface of striped jack after feeding them the formulated feed of the Examples or Comparative Examples for 5 months (n=10). Error bars indicate standard error. [Figure 5] The average amount of protein recovered from the body surface of amberjack fish after they were fed the formulated feed of the Example or Comparative Example for four months (n=10). Error bars indicate standard error, and double asterisks indicate that the p-value obtained by t-test was less than 0.01. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention relates to a mucus production promoter containing mealworms as an active ingredient, a compound feed containing the mucus production promoter, and a method for producing farmed fish using the compound feed. The present invention will be described in detail below based on embodiments of the invention, but the present invention is not limited to the embodiments shown below.

[0011] The mucus production promoter of the present invention promotes the production of body surface mucus in aquatic animals. In one embodiment, the aquatic animal is a fish. Preferred examples of fish include fish belonging to the orders Perciformes, Salmoniformes, Pleuronectiformes, Tetraodontiformes, Anguilliformes, Osmeriformes, Cypriniformes, and Siluriformes. More specific examples include farmed fish such as yellowtail, amberjack, yellowtail amberjack, red sea bream, striped jack, horse mackerel, bluefin tuna, tiger puffer, filefish, flounder, Japanese sea bass, grouper, red spotted grouper, yellow spotted grouper, grouper, coho salmon, rainbow trout, Atlantic salmon, amago (Japanese jack masu), yamame (cherry salmon), char, eel, conger eel, spotted amberjack, cobia, sweetfish, carp, koi carp, tilapia, catfish, and pangasius. In the present invention, the species of farmed fish is not limited as long as the mucus production promoter can exert its mucus production effect.

[0012] Generally, the mucus on the surface of fish contains physiologically active substances such as complement proteins, lectins, lysozyme, proteases, immunoglobulins, and antimicrobial peptides, and functions to protect the living body from the external environment. When a fish produces a large amount of mucus on the surface of its body, it is believed that the defense against pathogens invading from the outside works effectively, and the health of the fish is maintained in good condition. The present invention has the effect of maintaining the health of the fish in good condition or improving the health of the fish by promoting the production of mucus on the surface of the fish.

[0013] The amount of mucus produced on the surface of a fish is measured by the amount of protein that can be recovered from the surface of the fish per unit area. In one embodiment, the amount of mucus produced on the surface of the fish can be measured by the Bradford method. In the Bradford method, a certain area (e.g., 10 cm) of the surface of the fish is measured. 2 The mucus in the range of 1000 to 15000 is scraped off with a scraper, suspended in an isotonic solution, centrifuged, and the resulting supernatant is filtered to prepare the sample for measurement. The amount of protein present in the sample is then measured by absorbance at 595 nm using Coomassie blue dye, which turns blue when it binds to proteins.

[0014] The mucus production-promoting agent of the present invention can be orally administered to aquatic animals such as fish by preparing a compound feed containing the mucus production-promoting agent and feeding the compound feed to the aquatic animals such as fish. The compound feed may be in the form of extruded pellets, moist pellets, dry pellets, etc., and is not limited as long as it can contain the mucus production-promoting agent.

[0015] The content of the mucus production promoter in the compound feed is not limited as long as it can exert a mucus production promoting effect, but specifically, it can be 0.1% by weight to 50% by weight per total weight, 1% by weight to 20% by weight per total weight, or 3% by weight to 10% by weight per total weight.

[0016] In addition to the mucus production promoter, the compound feed contains feed ingredients that supply nutrients necessary for the growth of farmed fish. Specific examples of the feed ingredients include fish meal, fish oil, chicken meal, soybean meal, corn gluten meal, vegetable oils and fats, defatted rice bran, minerals, vitamins, etc. The compound feed of the present invention is produced by appropriately combining the mucus production promoter and these ingredients based on the type and growth stage of the farmed fish.

[0017] The mucus production-promoting agent of the present invention is orally administered to aquatic animals by being contained in or added externally to compound feed. The period of oral administration is not limited as long as the mucus production-promoting effect is achieved, but specifically may be from one day to one year, one week to nine months, or one month to seven months. Oral administration may be performed daily, one to six times a week, or once every two or three days during the aforementioned period.

[0018] The present invention also provides a method for producing farmed fish, comprising a feeding step of feeding a formula feed to farmed fish. The feeding step is a step of feeding a formula feed containing or to which a mucus production-promoting agent is externally added. In one embodiment of the production method, the feeding period of the formula feed containing or to which a mucus production-promoting agent is externally added may be one day to one year, one week to nine months, or one month to seven months. The formula feed may be fed daily during the aforementioned period, or at a frequency of one, two, three, four, five, or six times a week, or once every two or three days. In another embodiment, the formula feed containing or to which a mucus production-promoting agent is externally added may be fed continuously, or may be fed alternately with formula feed not containing or to which a mucus production-promoting agent is externally added.

[0019] As will be apparent from the examples described below, the mucus production promoting effect was confirmed in the cultured fish fed the feed, from fry to adult fish. Therefore, the weight of the cultured fish to be fed is not limited as long as they can consume the compound feed, and can be, for example, 1 g to 100 kg.

[0020] The mucus production promoter of the present invention has an insect as an active ingredient. The insect is preferably a beetle, more preferably an insect belonging to the family Tenebrionidae. In such a case, the insect may be the mealworm (Tenebrio obscurus), the brown mealworm (Tenebrio molitor), the red flour beetle (Tribolium castaneum), the rice mealworm (Alphitobius diaperinus), or the brown mealworm (Zophobos Morio), more preferably their larvae. In one embodiment, the insect may be a mealworm. Mealworm is generally the name given to the larvae of the brown mealworm (T. molitor).

[0021] The mucus production promoter may be the insect itself, but is preferably powdered. This is because powdered mucus production promoters can easily produce compound feed containing the mucus production promoter. In another embodiment, the mucus production promoter may be a liquid preparation obtained by extracting a fraction having a mucus production-promoting effect from an insect.

[0022] In one embodiment, the mealworms are defatted mealworms defatted using a supercritical fluid, more preferably defatted mealworm powder. A supercritical fluid refers to a fluid in a physical state above its critical temperature and critical pressure. Carbon dioxide is preferably used as the supercritical fluid for defatting, but other fluids can also be used. The critical temperature of carbon dioxide is 31.1°C, and the critical pressure of carbon dioxide is 7.38 MPa. Carbon dioxide in a supercritical state can be obtained by heating and / or pressurizing carbon dioxide so that the temperature exceeds these critical temperatures and pressures.

[0023] The present invention provides a method for producing a mucus production promoter, which includes a defatting step of defatting mealworms with a supercritical fluid. The defatting step may include a mixing step of mixing mealworms with a supercritical fluid to obtain a mixture, and a separation step of separating the defatted mealworms from the mixture. Since the lipids contained in the mealworms are dissolved in the supercritical fluid, the separation step separates the lipid-containing supercritical fluid to obtain defatted mealworms.

[0024] Generally, dried mealworms contain about 30% by weight of lipids per total weight, but mealworms obtained by defatting dried mealworms with supercritical carbon dioxide contain about 3.0 to 4.5% by weight of lipids per total weight. In other words, one embodiment of the manufacturing method of the present invention includes a defatting step in which dried mealworms are defatted with supercritical carbon dioxide, and this defatting step can be a step of removing about 85 to 90% by weight of the lipids contained in the dried mealworms. [Example]

[0025] The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0026] Defatted mealworms were used as a mucus production promoter. Dried larvae of the yellow mealworm (T. molitor) were defatted using supercritical carbon dioxide. The dried larvae before defatting contained approximately 30% lipid by weight, but by defatting using supercritical carbon dioxide, defatted mealworms containing approximately 4% lipid by weight were produced. Powdered defatted mealworms were used as a mucus production promoter.

[0027] Formula feeds containing 10% by weight of a mucus production promoter made from defatted mealworms (Example 1) and 3% by weight of a mucus production promoter (Example 2) were produced. Comparative feeds were also produced, which had the same composition as each example except that they did not contain the mucus production promoter. The feed compositions of the examples and comparative examples, other than the mucus production promoter, varied depending on the fish species.

[0028] The compound feed of Example 1 was fed to red sea bream, mojako (young yellowtail) and striped jack, and the compound feed of Example 2 was fed to amberjack for 1 to 7 months. The compound feed was fed to the farmed fish 2 to 5 times per week, and the feeding frequency varied depending on the fish species. The fish weight at the start and the feeding period for each fish species are shown in the table below. After the feeding period, the test fish were immediately killed and cut into 10cm pieces. 2 The mucus was suspended in phosphate-buffered saline. The suspension was centrifuged, and the resulting supernatant was filtered to prepare a measurement sample. The protein content of the sample was measured using the Bradford method.

[0029] [Table 1]

[0030] The amount of protein recovered per unit area from the body surface of each fish species fed the formulated feed of the Examples or Comparative Examples is shown in Figures 1 to 6. For all fish species, the amount of protein recovered from farmed fish fed the formulated feed of the Examples was higher than that of the Comparative Examples, and a significant difference in protein amount was confirmed in red sea bream and amberjack. Therefore, the mucus production-promoting effect of the mucus production promoter of this Example on farmed fish was confirmed.

Claims

1. A mucus production promoter containing mealworms as an active ingredient.

2. The mucus production promoter of claim 1, wherein the mealworms are defatted mealworms.

3. The mucus production promoter according to claim 2, wherein the defatted mealworms are defatted using a supercritical fluid.

4. The mucus production promoter according to any one of claims 1 to 3, which is for use in fish.

5. A compound feed containing the mucus production promoter according to claim 4 in an amount of 3 to 10% by weight based on the total weight of the feed.

6. A method for producing farmed fish, comprising a feeding step of feeding the compound feed according to claim 5 to farmed fish.

7. The method for producing farmed fish according to claim 6, wherein the feeding step comprises feeding the compound feed for 1 month to 7 months.

Images