Sea urchin gonad hypertrophy promoter, sea urchin compound feed, sea urchin production method, and use in sea urchin cultivation

Abstract

There was a need for feed that would have an even greater effect on gonad enlargement than conventional technology, as well as feed that would shorten the period required to produce sea urchins and reduce the amount of feed needed. [Solution] A sea urchin gonad enlargement promoter containing sterol and / or its ester as an active ingredient, a sea urchin compound feed containing the sea urchin gonad enlargement promoter, a method for producing sea urchins which includes a step of feeding the sea urchin compound feed to sea urchins, and the use of sterol and / or its ester in raising sea urchins.

Description

[Technical Field]

[0001] The present invention relates to a sea urchin gonad hypertrophy promoter, a formulated feed for sea urchins, a method for producing sea urchins, and uses in raising sea urchins. [Background technology]

[0002] The edible part of sea urchins is the gonad, and feed for enlarging the gonad of sea urchins and aquaculture methods for enlarging the gonad of sea urchins are known. For example, there is a sea urchin aquaculture feed that does not contain animal protein but contains proteins derived from seaweed and wheat flour (see Patent Document 1), a sea urchin feed consisting of dried gelatinized rice with powdered seaweed dispersed therein (Patent Document 2), a method for raising or cultivating sea urchins by feeding them legumes (Patent Document 3), Examples include sea urchin livestock feed containing seaweed and sea urchin internal organs or crushed materials thereof (Patent Document 4), and sea urchin feed characterized by adding carotenoids to a basic feed containing at least animal and plant protein-containing materials and seaweed (Patent Document 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-101401 [Patent Document 2] Japanese Patent Application Publication No. 2022-149294 [Patent Document 3] Patent No. 7249026 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-187337 [Patent Document 5] Japanese Patent Application Publication No. 06-098691 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present invention have discovered that sea urchins with gonads that have a strong umami and sweet taste and little bitterness can be produced in a short period of time by feeding sea urchins a feed that does not contain animal protein but contains proteins derived from seaweed and wheat flour (see Patent Document 1). On the other hand, there has been a demand for a feed that has a stronger effect on gonad enlargement than conventional techniques, as well as a feed that can shorten the period required for sea urchin production and reduce the amount of feed that can be fed.

[0005] It was known that feeding sea urchins a diet with a high protein content would result in gonad enlargement in a short period of time. However, the gonads of sea urchins raised on a diet with a high protein content had a strong bitter taste, reducing their commercial value. The present invention was achieved by identifying a nutritional component, different from protein, that has the effect of promoting gonad enlargement in sea urchins. [Means for solving the problem]

[0006] That is, the present invention provides a sea urchin gonad hypertrophy promoter containing a sterol and / or an ester thereof as an active ingredient. The sea urchin gonad hypertrophy promoter may be a sea urchin gonad hypertrophy promoter containing avian eggs as a source of the sterol and / or an ester thereof. Furthermore, the sea urchin gonad hypertrophy promoter may be a sea urchin gonad hypertrophy promoter containing vegetable oil as a source of the sterol and / or an ester thereof.

[0007] Another aspect of the present invention provides a sea urchin formula feed containing sterols and / or esters thereof. The sterol and / or ester content may be 1 mg / g or more. The sea urchin formula feed may contain vegetable oil as a source of the sterols and / or esters thereof. Another sea urchin formula feed may contain avian eggs as a source of the sterols and / or esters thereof.

[0008] Another sea urchin formula feed may be a sea urchin formula feed containing avian eggs. In such a case, the avian eggs may contain egg yolk. The avian eggs contained in the sea urchin formula feed may be one or more selected from dried whole eggs, dried egg yolks, dried whole egg and / or dried egg yolk powder, egg oil, egg yolk oil, and powder containing egg oil and / or egg yolk oil. The mixing ratio of the avian eggs may be 1% to 50% by weight.

[0009] Another sea urchin formula feed is a cholesterol-containing formula feed for sea urchins, in which the cholesterol content of the total sterol content may be 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50% by weight or more and less than 100% by weight.

[0010] Another present invention provides a method for producing sea urchins, comprising the step of feeding sea urchins a sea urchin formula feed. Another present invention provides a use of sterols and / or esters thereof in raising sea urchins. Here, the use may be the use of avian eggs as a source of sterols and / or esters thereof in raising sea urchins. Alternatively, the use may be the use of vegetable oil as a source of sterols and / or esters thereof in raising sea urchins. [Effects of the Invention]

[0011] By using the sea urchin gonad hypertrophy promoter of the present invention, a higher effect of hypertrophying the sea urchin gonads than conventional methods can be achieved. By using the gonad hypertrophy promoter and sea urchin compound feed of the present invention, effects such as improved yield of edible parts of sea urchins, shortened culture period, and / or reduced feed amount can be obtained compared to conventional techniques. Furthermore, the gonads produced by the present invention have a strong umami and sweet taste and little bitterness. Furthermore, the present invention contributes to improving the profitability of sea urchin culture. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a graph showing the correlation between the total sterol content in the diet and the average gonad-body index of sea urchins. The error bars in the figure indicate the standard error. [Figure 2] 1 is a graph showing the average values of the gonad somatic index of sea urchins before feeding and after feeding with the Examples and Comparative Examples. Error bars indicate standard deviation, and different letters indicate that a significant difference was found in the GSI after feeding by one-way ANOVA followed by Turkey's test (p<0.05). [Figure 3]1 is a graph showing the average values of the gonad somatic index of sea urchins before feeding and after feeding with the Examples and Comparative Examples. Error bars indicate standard deviation, and different letters indicate that a significant difference was found in the GSI after feeding by one-way ANOVA followed by Turkey's test (p<0.05). [Figure 4] 1 is a graph showing the average values of the gonad somatic index of sea urchins before feeding and after feeding with the Examples and Comparative Examples. Error bars indicate standard deviation, and different letters indicate that a significant difference was found in the GSI after feeding by one-way ANOVA followed by Turkey's test (p<0.05). DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below based on the embodiments for carrying out the present invention, but the present invention is not limited to these embodiments.

[0014] The present invention provides a sea urchin gonad hypertrophy promoter containing a sterol as an active ingredient. The sea urchin gonad hypertrophy promoter contains a sterol as an active ingredient. Sterol is a general term for compounds having a cyclopentanohydrophenanthrene ring. The sterol contained in animals is mainly cholesterol, which is known as an zoosterol. Plant sterols contained in plants are also called phytosterols, and representative plant sterols include brassicasterol, 7-ergostenol, campesterol, isofucosterol, stigmasterol, 7-stigmasterol, β-sitosterol, and avenasterol. Ergosterol is known as a sterol contained in fungi. Triterpene alcohols contained in rice bran oil are also a type of sterol.

[0015] Furthermore, the sterol that is the active ingredient of the sea urchin gonad hypertrophy promoter may be a sterol derivative. Examples of the sterol derivative include sterol esters. Examples of the sterol esters include esters of sterol and fatty acids, and esters of sterol and ferulic acid. Also, sterol glycosides in which sterol is bound to sugar are exemplified as sterol derivatives.

[0016] A sea urchin gonad hypertrophy promoter containing a sterol and / or a derivative thereof, when administered to a sea urchin, has the effect of promoting gonad hypertrophy in the body of the sea urchin. Examples of routes of administration to sea urchins include intracoelomic administration, transdermal administration, and oral administration. In the case of oral administration, the sea urchin gonad hypertrophy promoter of the present invention can be given as is, or a compound feed containing the sea urchin gonad hypertrophy promoter, and the sea urchin ingests the sea urchin gonad hypertrophy promoter or the compound feed, thereby orally administering the sea urchin gonad hypertrophy promoter to the sea urchin.

[0017] In one embodiment, the gonadal hypertrophy promoter may contain avian eggs as a sterol source. The avian eggs are preferably avian eggs for food and / or feed, and examples thereof include eggs of chickens, quails, ducks, geese, turkeys, pigeons, pheasants, ostriches, emus, etc. In this embodiment, among avian eggs, chicken eggs are preferably used.

[0018] Since avian eggs are used as a sterol source, more specifically, a cholesterol source, it is preferable that the avian eggs contain at least egg yolk. The avian eggs contained in the gonad enlargement promoter may be, for example, dried whole eggs, dried egg yolks, or powders thereof. Furthermore, the avian eggs contained in the gonad enlargement promoter may be egg oil or egg yolk oil extracted from whole eggs or egg yolks, or powders containing them.

[0019] In one embodiment, the gonadal hypertrophy promoter may contain a plant as a sterol source. The plant as a plant sterol source is an edible and / or feed plant, specifically, rice, brown rice, wheat, beans, vegetables, fruits, powders thereof, vegetable oils extracted therefrom, or powders containing vegetable oils extracted therefrom.

[0020] Specific examples of vegetable oils that can be used as sterol sources include rice bran oil, rapeseed oil, soybean oil, corn oil, sunflower seed oil, and peanut oil. Another example of vegetable oil is a plant sterol concentrate produced from vegetable oil. One example of a plant sterol concentrate is obtained by deacidifying and distilling vegetable oil.

[0021] The present invention provides a compound feed for sea urchins. The compound feed is made by molding multiple raw materials into pellets, and is called dry pellets (DP), extruded pellets (EP), etc. depending on the molding method. The compound feed for sea urchins has properties suited to the feeding behavior of sea urchins, specifically, the properties of sinking in seawater and maintaining the shape for a certain period of time in seawater.

[0022] The present invention provides a sterol-containing compound feed for sea urchins. Sterol is a general term for compounds containing a cyclopentanohydrophenanthrene ring. The sterol contained in animals is mainly cholesterol, which is known as an zoosterol. Plant sterols contained in plants are also called phytosterols, and representative plant sterols include brassicasterol, 7-ergostenol, campesterol, isofucosterol, stigmasterol, 7-stigmasterol, β-sitosterol, and avenasterol. Ergosterol is known as a sterol contained in fungi. Triterpene alcohols contained in rice bran oil are also a type of sterol.

[0023] Total sterols is defined as the sum of the contents of representative sterols, including cholesterol, brassicasterol, 7-ergostenol, campesterol, isofucosterol, stigmasterol, 7-stigmasterol, β-sitosterol, and avenasterol.

[0024] The sterol content of the compound feed of the present invention may be defined as the content of individual sterols such as cholesterol, β-sitosterol, campesterol, isofucosterol, etc., or may be defined as the total sterol amount.

[0025] The sterol-containing sea urchin compound feed of the present invention may be produced by blending highly pure sterols with other raw materials, but it can also be produced by blending raw materials that serve as sterol sources with other raw materials.

[0026] In one embodiment, the sea urchin formulated feed may contain a plant-derived raw material as a sterol source. Examples of the plant-derived raw material as a plant sterol source include rice, brown rice, wheat, beans, vegetables, fruits, powders thereof, vegetable oils extracted therefrom, and powders containing vegetable oils.

[0027] Specific examples of vegetable oils that can be used as sterol sources include rice bran oil, rapeseed oil, soybean oil, corn oil, sunflower seed oil, and peanut oil. Another example of vegetable oil is a plant sterol concentrate produced from vegetable oil. One example of a plant sterol concentrate is obtained by deacidifying and distilling vegetable oil.

[0028] Another aspect of the present invention provides a sea urchin formula feed containing avian eggs. The avian eggs to be added to the formula feed are preferably avian eggs for food and / or feed, and examples thereof include eggs from chickens, quails, ducks, geese, turkeys, pigeons, pheasants, ostriches, emus, etc. In this embodiment, among avian eggs, chicken eggs are preferably used.

[0029] In sea urchin formulated feed containing avian eggs, the avian eggs are used as a sterol source, more specifically a cholesterol source, and therefore it is preferable that the avian eggs contain at least egg yolk. The avian eggs contained in the sea urchin formulated feed may be, for example, dried whole eggs, dried egg yolks, or powders thereof. Furthermore, the avian eggs contained in the sea urchin formulated feed may be egg oil or egg yolk oil extracted from whole eggs or egg yolks, or powders containing them.

[0030] In one embodiment, the blending ratio of avian eggs in the sea urchin formulated feed is 1 to 50% by weight, 2 to 30% by weight, or 5 to 10% by weight. Since the formulated feed is mainly produced from dry powder, the blending ratio is expressed as a numerical value per dry weight. That is, the blending ratio of avian eggs in the sea urchin formulated feed of one embodiment is 1 to 50% by weight (per dry weight), 2 to 30% by weight (per dry weight), or 5 to 10% by weight (per dry weight).

[0031] In one embodiment, the sea urchin formulated feed contains no or almost no animal protein other than avian eggs. Animal protein refers to protein contained in raw materials derived from animals (animal raw materials). General formulated feed contains protein-rich animal raw materials for the purpose of increasing the protein content in the feed. Examples of protein-rich animal raw materials include fish meal, fish meat, casein, chicken meal, feather meal, insect meal, collagen, etc., but one embodiment of the sea urchin formulated feed of the present invention contains no or almost no animal raw materials.

[0032] Formula feed that contains no or almost no animal protein other than avian eggs means a formula feed that does not contain any animal ingredients used for the purpose of ingesting animal protein. Therefore, it is acceptable for the formula feed to contain animal ingredients for purposes other than ingesting animal protein, such as feed ingredients in which animal ingredients are used as excipients and / or stabilizers, or feed additives (e.g., pigments, vitamins, minerals, amino acids, etc.). Specific examples of animal ingredients used as excipients and / or stabilizers include gelatin, lactose hydrate, and animal glycerin.

[0033] When compound feed contains animal ingredients for a purpose other than the purpose of ingesting animal protein, the blending ratio of the animal ingredients may be, for example, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.5% by weight or less, or 0.1% by weight or less.

[0034] Even if the raw material is animal-derived, it is permissible for the sea urchin formulated feed of the present invention to incorporate raw materials that are substantially free of protein, such as animal fats and oils such as fish oil, beef tallow, lard, etc. Fish oil is rich in omega-3 fatty acids, which are important nutritional components for sea urchins, so its incorporation into the sea urchin formulated feed is permissible.

[0035] Furthermore, in one embodiment of the sea urchin compound feed, apart from seaweed and wheat flour, no vegetable feed ingredients with a high protein content are blended. Specific examples of vegetable feed ingredients with a high protein content include corn gluten meal and defatted soybeans (soybean meal). That is, in one embodiment of the compound feed of the present invention, no ingredients derived from corn or soybeans and with a high protein content, such as corn gluten meal or defatted soybeans, are blended. Specific examples of ingredients with a high protein content include ingredients containing 30% or more by weight of protein per dry weight, ingredients containing 40% or more by weight of protein per dry weight, and ingredients containing 50% or more by weight of protein per dry weight.

[0036] In one embodiment of the sea urchin formula feed containing avian eggs, the sea urchin formula feed contains substantially no protein other than the seaweed, wheat flour, and avian eggs. In this formula feed, other than the seaweed, wheat flour, and avian eggs, ingredients that do not contain protein and / or ingredients with low protein content are mainly blended, with protein-containing ingredients being blended in at very low ratios. Specific examples of ingredients that do not contain protein or have low protein content include fats and oils, carbohydrates such as starch, cellulose, and carboxymethylcellulose (CMC), and inorganic substances such as salt (sodium chloride), calcium chloride, magnesium chloride, and phosphorus. Other examples include minerals, vitamins, pigments, etc.

[0037] In one embodiment, the protein content of the sea urchin formula feed may be 3% to 20% by weight, 5% to 15% by weight, or 7% to 10% by weight (all by dry weight). If the protein content is lower than the above-mentioned range, there is a risk that a sufficient effect of gonad enlargement will not be obtained, while if the protein content is high, the gonads obtained from the fed sea urchins will taste bitter.

[0038] In one embodiment of the sea urchin formula feed containing avian eggs, seaweed, wheat flour, and avian eggs are the main protein sources, and the protein in the entire feed is mainly composed of proteins derived from seaweed, wheat flour, and avian eggs. Whole egg powder and egg yolk powder, for example, have a protein content of 40 to 50% by weight (dry weight), which is higher than that of seaweed or wheat flour. Therefore, in the sea urchin formula feed containing whole egg powder and / or egg yolk powder as avian eggs, the protein derived from avian eggs accounts for a certain proportion of the protein in the entire feed.

[0039] In this embodiment, ingredients with a higher protein content than whole egg powder or egg yolk powder are not blended, and as a result, the proportion of proteins derived from whole egg powder or egg yolk powder in the overall protein of the feed becomes large. For example, in a sea urchin formula feed, proteins derived from avian eggs may account for 20 to 60 wt % or 25 to 50 wt % of the total protein of the feed. Here, the proteins derived from avian eggs may be proteins derived from whole egg powder and / or egg yolk powder.

[0040] On the other hand, sea urchin formula feed containing egg oil and / or egg yolk oil as avian eggs contains little or no protein derived from avian eggs, because egg oil and / or egg yolk oil contains little or no protein.

[0041] In one embodiment, the sea urchin formula feed contains sterols. The total sterol content in the feed may be 1, 1.5, or 2 mg / g or more. The sterol may be an animal sterol or a plant sterol. By incorporating the above-mentioned sterol source into the formula feed, the formula feed can contain sterols. From the examples, it was confirmed that a formula feed containing 1 mg / g, preferably 1.5 mg / g, of total sterols has a high effect of promoting gonadal hypertrophy.

[0042] In one embodiment, the sea urchin formula feed contains cholesterol. The cholesterol content in the feed can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2 mg / g or more. By adding the above-mentioned cholesterol source to the formula feed, the formula feed contains cholesterol.

[0043] When the sea urchin formula feed contains cholesterol, the proportion of cholesterol in the total sterols in the feed is 20, 30, 40, 50, 60, 70, 80, or 90% by weight or more and less than 100% by weight. From the examples, it is considered that cholesterol has a stronger effect of promoting gonad enlargement than other sterols, and it was confirmed that when cholesterol accounts for 50% by weight or more of the total sterols in the feed, a particularly strong effect of promoting gonad enlargement was observed.

[0044] The present invention also provides a method for producing sea urchins. The method for producing sea urchins includes feeding the above-described compound feed to sea urchins. In one embodiment of the method for producing sea urchins, sea urchins with a low edible part yield are used. Preferably, the edible part yield of the sea urchins before feeding is 10% by weight or less on average, and can be 9, 8, 7, 6, 5, 4, or 3% by weight or less. The period required for production is 1 to 6 months, preferably 1 to 3 months. By feeding 1 to 3 times a week, preferably at least once a week, and 3 to 24 times a week, preferably 4 to 6 times a week during the cultivation period, sea urchins with an edible part yield of 10% by weight or more on average, preferably 15% by weight or more can be produced.

[0045] Furthermore, the present invention relates to the use of sterols and / or esters thereof in the cultivation of sea urchins. The sterols and / or esters thereof are used in the cultivation of sea urchins for the purpose of increasing the gonadal enlargement of the sea urchins. The sterols and / or esters thereof are administered to the sea urchins by intracoelomal, transdermal, and / or oral administration.

[0046] When the sterol and / or ester thereof is orally administered to the sea urchin, in one embodiment, the sterol and / or ester thereof is fed to the sea urchin as is. The sea urchin ingests the sterol and / or ester thereof, thereby orally administering the sterol and / or ester thereof to the sea urchin.

[0047] In one embodiment, when the sterol and / or ester thereof is orally administered to the sea urchin, the sterol and / or ester thereof is fed to the sea urchin as a compound feed containing the sterol and / or ester thereof. The sterol and / or ester thereof is orally administered to the sea urchin by the sea urchin eating the compound feed.

[0048] Furthermore, the present invention relates to the use of a source of sterols and / or esters thereof in the cultivation of sea urchins. The source of sterols and / or esters thereof is a plant or animal that is rich in sterols and / or esters thereof. The source is used to administer sterols and / or esters thereof to sea urchins.

[0049] When the supply source is a plant, rice, brown rice, wheat, beans, vegetables, fruits, powders thereof, vegetable oils extracted therefrom, powders containing vegetable oils, and / or concentrates of plant sterols produced from vegetable oils are used.

[0050] When the source is an animal, it may be an avian egg. Among avian eggs, chicken eggs are preferably used. Since avian eggs are used as a sterol source, more specifically a cholesterol source, it is preferable that they contain at least egg yolk, and for example, they may be dried whole eggs, dried egg yolks, powders thereof, egg oil or egg yolk oil obtained by extraction from whole eggs or egg yolks, and / or powders containing them.

[0051] These supply sources are used by feeding them to sea urchins as they are or as a compound feed containing the supply sources. When the sea urchins eat the supply sources as they are or as a compound feed containing the supply sources, the sterols and / or their esters are orally administered to the sea urchins.

[0052] The moisture, protein, lipid, and ash values of the compound feed of the present invention and the feed ingredients blended therein are obtained by the analytical methods specified in the Feed Analysis Standards (Director-General of the Food Safety and Consumer Affairs Bureau, Ministry of Agriculture, Forestry and Fisheries, Japan). For example, the moisture content of the aquaculture feed of the present invention is 3% to 25% by weight per total weight, the protein content is 3% to 15% by weight per dry weight, the lipid content is 1% to 5% by weight per dry weight, and the ash content is 10% to 30% by weight per dry weight. [Example]

[0053] The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0054] Preparation of sea urchin feed and rearing test using the feed (1)

[0055] Examples and comparative examples of compound feed for sea urchins were prepared. Table 1 shows the compositions and measured protein values of the examples and comparative examples. Cholesterol (manufactured by Nacalai Tesque, Inc., Nacalai standard special grade) was added to Examples 1 and 2. Rice sterol ester (manufactured by Tsuno Foods Industry Co., Ltd.) was used as the source of plant sterol in Examples 3 and 4. Rice sterol ester is a powder whose main components are esters of plant sterols and triterpene alcohols with fatty acids, and which also contains free fatty acids and silicic anhydride.

[0056] The sterol contents of the Examples and Comparative Examples, calculated from the sterol contents of the raw materials used in the Examples and Comparative Examples, are shown in Table 2. Here, the total sterol amount was defined as the sum of the contents of cholesterol, brassicasterol, campesterol, β-sitosterol, isofucosterol, stigmasterol, avenasterol, 7-stigmasterol, and 7-ergostenol, which are known as major sterols (the same applies hereinafter).

[0057] The lower limit of quantitation for each sterol was 1 mg / 100 g, but due to the presence of inhibitors, the lower limit of quantitation for brassicasterol in rice sterol esters was 10 mg / 100 g, and 7-stigmastenol, 7-ergostenol, and avenasterol in rice sterols could not be analyzed. Sterol contents below the lower limit of quantitation and those that could not be analyzed were considered to be zero, and the amount of sterols in the feed was calculated.

[0058] The feed ingredients listed in the table were mixed with an appropriate amount of water, formed into cylinders approximately 2 cm in diameter, steamed in a steamer for 10 minutes, cut into disks approximately 1 cm thick, and dried overnight or longer at 70°C in a hot air dryer to obtain a compound feed. The protein content of the compound feed was measured using the Kjeldahl method. The protein conversion factor was set to 6.25.

[0059] As shown in the table below, the protein content of all the feeds was almost the same. Furthermore, the cholesterol content of the total sterols in the feeds of Examples 1 and 2 was high, at over 60% by weight. Because the feeds of Examples 3 and 4 contained 5-10% by weight of rice sterols, the cholesterol content of the total sterols in these feeds was relatively low.

[0060] [Table 1]

[0061] [Table 2]

[0062] A rearing experiment was conducted using northern purple sea urchins (average shell diameter 56.9 mm, average weight 78.0 g) caught in Setana Town, Hokkaido. The sea urchins were housed in 60 L square tanks and fed 5-6 times a week at a rate of approximately 12% of their body weight per week, with the amount of food fed adjusted based on the amount of remaining food. Feeding was terminated 10 weeks after initiation. Seawater temperatures during the rearing period ranged from 10.9 to 14.6°C. Four individuals from each group were dissected to obtain the gonadal somatic index (GSI).

[0063] The correlation between the mean GSI at the end of each group and the total sterol content of the formula feed fed is shown in Figure 1. As shown in Figure 1, the coefficient of determination (R 2 The correlation coefficient (value) was 0.8156, and an extremely strong correlation was confirmed between the two. Therefore, it was demonstrated that sterols can be used as an active ingredient in a sea urchin gonad hypertrophy promoter.

[0064] Preparation of sea urchin feed and rearing test using the feed (2)

[0065] Chicken eggs were boiled in boiling water, the eggshells removed, and then dried and powdered to obtain whole egg powder. Diethyl ether was used to extract the oil that dissolves in diethyl ether from the whole egg powder. Four times the weight of diethyl ether was added to the whole egg powder and stirred for 9 hours, and the solids were removed using filter paper to obtain a liquid fraction. Diethyl ether was removed from the liquid fraction using an evaporator to obtain egg oil. The obtained egg oil accounted for 15.1% by weight of the whole egg powder.

[0066] Using whole egg oil and other ingredients, examples and comparative examples of sea urchin formula feed were prepared using the same method as in (1). Table 3 shows the compositions and protein measurements for the examples and comparative examples. In Examples 7 and 8, rice sterol ester (manufactured by Tsuno Foods Co., Ltd.) was added as a plant sterol source. Table 4 shows the results of measuring the amount of sterols contained in the feed using gas chromatography. The lower limit of quantitation is 1 mg / 100 g, but due to the presence of measurement inhibitors, the lower limits of quantitation for 7-stigmastenol and 7-ergostenol were 10 mg / 100 g in Example 7 and 5 mg / 100 g in Example 8. Furthermore, avenasterol could not be analyzed in Examples 7 and 8. In the table, other "-"s indicate values below the lower limit of quantitation.

[0067] [Table 3]

[0068] [Table 4]

[0069] A rearing experiment was conducted using northern purple sea urchins (average shell diameter 50.5 mm, average weight 49.4 g) caught in Setana Town, Hokkaido. The sea urchins were housed in 60 L square tanks and fed 5-6 times a week at a rate of approximately 12% of their body weight per week, with the amount of food fed adjusted based on the amount of remaining food. Feeding was terminated 5 weeks after initiation. Seawater temperature during the rearing period ranged from 12.7 to 17.2°C. After the end of feeding, the animals were stopped from feeding for one week, and 14 individuals from each group were dissected to determine the gonadal somatic index (GSI).

[0070] The sea urchins used in this test were a mixture of healthy and unhealthy ones, and it was suggested that the unhealthy ones were not feeding, so the top nine individuals in each group with the highest GSI were extracted. Figure 2 shows the average GSI of the top nine individuals in each group. Although the feeding period in (1) was 10 weeks, the feeding period in this test was only 5 weeks, and many individuals in the examples were found to have a GSI of over 10% by weight.

[0071] Furthermore, the GSI tended to be higher in the groups fed a diet with a high sterol content. In particular, in Examples 5 and 6, which were fed a diet containing egg oil, a significant increase in GSI was observed compared to the comparative example, indicating that cholesterol is highly effective among sterols.

[0072] Preparation of sea urchin feed and rearing test using the feed (3)

[0073] Using whole egg powder (Kewpie Egg Corporation) as a cholesterol source, examples and comparative examples of sea urchin formula feed were prepared in the same manner as in (1). Table 5 shows the compositions and measured protein amounts of the examples and comparative examples. The protein content of the whole egg powder was 46% by weight, and the protein content of the wheat flour and seaweed powder was 12% by weight, so the protein content derived from the whole egg powder in the examples was calculated to be 32% to 50% by weight.

[0074] The sterol contents of the examples and comparative examples, calculated from the sterol contents of the raw materials used in the examples and comparative examples, are shown in Table 6. The lower limit of quantification for each sterol was 1 mg / 100 g, and the sterol content in the feed was calculated by regarding sterol contents below the lower limit of quantification as zero. The proportion of cholesterol content in the total sterol content in the examples was calculated to be 76% to 91% by weight.

[0075] [Table 5]

[0076] [Table 6]

[0077] A rearing experiment was conducted using northern purple sea urchins (average shell diameter 53.9 mm, average weight 71.5 g) caught in Setana Town, Hokkaido. The sea urchins were housed in 60 L square tanks and fed 5-6 times a week at a rate of approximately 12% of their body weight per week, with the amount of food fed adjusted based on the amount of remaining food. Feeding was terminated 5 weeks after initiation. Seawater temperature during the rearing period ranged from 12.5 to 16.1°C. After the end of feeding, the animals were stopped from feeding for one week, and 14 individuals from each group were dissected to determine the gonadal somatic index (GSI).

[0078] Figure 3 shows the average GSI for each group. The groups fed Examples 9 and 10, which contained whole egg powder, showed a significant increase in GSI compared to the comparative example. Despite the feeding period of 5 weeks, many individuals in Examples 9 and 10 exhibited a GSI of 15% by weight or more, which is the benchmark for high-quality sea urchin. Furthermore, the gonads obtained in Examples 9 and 10 had a strong umami and sweet taste, with almost no bitterness, indicating that high-quality sea urchin gonads were obtained in these examples.

[0079] Preparation of sea urchin feed and rearing test using the feed (4)

[0080] Using egg yolk powder (provided by Kewpie Corporation) as a cholesterol source, examples and comparative examples of sea urchin formula feed were prepared in the same manner as in (1). Table 7 shows the compositions and measured protein values of the examples and comparative examples. The protein content of the egg yolk powder was 35% by weight, and the protein content of the wheat flour and seaweed powder was 12% by weight, so the protein content derived from the egg yolk powder in the protein content of the examples was calculated to be 26% to 44% by weight.

[0081] The sterol contents of the examples and comparative examples, calculated from the sterol contents of the raw materials used in the examples and comparative examples, are shown in Table 6. The lower limit of quantification for each sterol was 1 mg / 100 g, and the sterol content in the feed was calculated by regarding sterol contents below the lower limit of quantification as zero. The proportion of cholesterol content in the total sterol content in the examples was calculated to be 80% by weight to 93% by weight.

[0082] [Table 7]

[0083] [Table 8]

[0084] A rearing experiment was conducted using northern purple sea urchins (average shell diameter 52.1 mm, average weight 54.9 g) caught in Setana Town, Hokkaido. The sea urchins were housed in 60 L square tanks and fed 5-6 times a week at a rate of approximately 12% of their body weight per week, with the amount of food fed adjusted based on the amount of remaining food. Feeding was terminated 5 weeks after the start of the experiment. Seawater temperature during the rearing period ranged from 13.6 to 21.4°C. After the end of feeding, the animals were stopped from feeding for one week, and 15 individuals from each group (7 individuals in Comparative Example 3) were dissected to obtain the gonadal somatic index (GSI).

[0085] Figure 4 shows the average GSI for each group. The groups fed Examples 11 and 12, which contained egg yolk powder, showed a significant increase in GSI compared to the comparative example. Despite the feeding period of 5 weeks, many individuals in Examples 11 and 12 exhibited a GSI of 15% by weight or more, which is the benchmark for high-quality sea urchin. Furthermore, the gonads obtained in Examples 11 and 12 had a strong umami and sweet taste, with almost no bitterness, indicating that high-quality sea urchin gonads were obtained in these examples.

Claims

1. A sea urchin gonad hypertrophy promoter comprising a sterol and / or its ester as an active ingredient.

2. A sea urchin gonad hypertrophy promoter containing bird eggs.

3. A sea urchin gonad enlargement promoter containing vegetable oil.

4. A sea urchin compound feed containing the sea urchin gonad hypertrophy promoter according to any one of claims 1 to 3.

5. A method for producing sea urchins, comprising the step of feeding sea urchins the compound feed for sea urchins described in claim 4.

6. This is a compound feed for sea urchins containing avian eggs, wherein the avian eggs are one or more selected from dried whole eggs, dried egg yolks, dried whole egg and / or dried egg yolk powder, egg oil, egg yolk oil, and powder containing egg oil and / or egg yolk oil.

7. The sea urchin formulated feed according to claim 6, wherein the blending ratio of the avian eggs is 1% by weight to 50% by weight.

8. 7. The sea urchin compound feed according to claim 6, which contains sterol and / or its ester.

9. The sea urchin compound feed according to claim 8, wherein the sterol is cholesterol.

10. 10. The sea urchin compound feed according to claim 9, wherein the cholesterol content in total sterols is 50% by weight or more and less than 100% by weight.

11. The sea urchin compound feed according to claim 8, wherein the content of the sterol and / or its ester is 1 mg / g or more.

12. A compound feed for sea urchins as described in claim 6, further containing vegetable oil.

13. A method for producing sea urchins, comprising a step of feeding sea urchins the sea urchin formulated feed according to any one of claims 6 to 12.

14. Use of sterols and / or esters thereof in inducing gonadal hypertrophy in sea urchins.

15. Use of avian eggs in the enlargement of the gonads of sea urchins.

16. Use of vegetable oil in the enlargement of the gonads of sea urchins.

Images