JP7650247B2 - Method for raising vitamin E enriched farmed fish - Google Patents

Description

The present invention relates to a method for raising farmed fish enriched with vitamin E.

In fish farming, a shift from live bait to compound feed is being promoted from the viewpoints of nutrition, stable supply, environmental pollution prevention, sustainable farming, etc., and various compound feeds have been developed. In particular, compound feeds tailored to the preferences of fish species have been proposed so that a shift to compound feed can be promoted for highly piscivorous fish species as well.
For example, Patent Document 1 and Patent Document 2 disclose fish feed having an outer layer and an inner layer. Patent Document 1 and Patent Document 2 disclose that these fish feeds are used for cultured fish such as tuna, which have high palatability, and that they have good feeding properties and feed efficiency. Patent Document 3 discloses a feed with a double structure consisting of an outer skin and an inner layer containing a protein raw material and liquid oil, and discloses that this feed has high feeding properties and suppresses oil leakage.

International Publication No. 2010/110326 JP 2012-65565 A JP 2014-45750 A

On the other hand, vitamin E is known to have antioxidant effects, and in living organisms, vitamin E exerts specific functions in different tissues. For this reason, it is required that the physiological effects of vitamin E in each tissue are high in farmed fish as well.
Therefore, an object of the present invention is to provide farmed tuna fish enriched in vitamin E, uses thereof, and a method for raising the same.

The present invention is as follows.
[1] A farmed tuna fish, in which at least one selected from the group consisting of muscle, liver, and eyeballs contains 2 mg or more of vitamin E per 100 g.
[2] The farmed tuna fish described in [1] above, obtained by raising and managing the fish with a feed containing a compound feed.
[3] The farmed tuna fish according to [1] or [2], having a relative pyloric caeca weight of 2% or more.
[4] A farmed tuna fish according to any one of [1] to [3], having a pyloric caeca containing 2 mg or more of vitamin E per 100 g.
[5] A farmed tuna fish according to any one of [1] to [4], having a total fish weight of 20 kg or more.
[6] A farmed tuna fish according to any one of [1] to [5], having a fork length of 90 cm or more.
[7] The farmed tuna fish according to any one of [1] to [6], having a fatness index of 20 or more.
[8] A farmed tuna fish according to any one of [1] to [7], which is a tuna of the genus Thunnus, the genus Bonito, the genus Scombrella, or the genus Skipjack.
[9] The farmed tuna fish according to any one of [1] to [8], which is albacore, bluefin tuna, southern bluefin tuna, Atlantic bluefin tuna, Atlantic bluefin tuna, yellowfin tuna, bigeye tuna, longfin tuna, bonito or spotted tuna.
[10] A farmed tuna fish according to any one of [1] to [8], which is a tuna fish that mainly feeds on fish native to the Northern Hemisphere.
[11] The farmed tuna fish according to [10], which is albacore, bluefin tuna, Atlantic bluefin tuna, yellowfin tuna, bigeye tuna, longfin tuna, bonito or spotted tuna.
[12] A farmed tuna fish according to any one of [1] to [11], from which at least one part selected from the group consisting of the gills, internal organs, tail and head has been removed.
[13] A farmed tuna fish according to any one of [1] to [12], in which the gills and internal organs have been removed.
[14] The farmed tuna fish according to [13], having a total weight of 17 kg or more.
[15] An edible portion of a farmed tuna fish containing 2 mg or more of vitamin E per 100 g.
[16] An edible portion of the farmed tuna fish described in [15], which is at least a part of fish meat, internal organs, eyeballs, skin or brain.
[17] The edible portion of the farmed tuna fish described in [15], which is lean meat or fatty meat.
[18] An edible part of the farmed tuna fish described in [15], which is at least one selected from the group consisting of liver, pyloric caeca, stomach, esophagus, intestines, testes, ovaries, spleen, heart and swim bladder.
[19] An unheated food product made from farmed tuna fish, comprising an unheated edible part of farmed tuna fish containing 2 mg or more of vitamin E per 100 g, and a container for storing the unheated edible part.
[20] A heated food product made from farmed tuna fish, comprising a heated edible part of farmed tuna fish containing 2 mg or more of vitamin E per 100 g, and a container for containing the heated edible part.
[21] A method for raising farmed tuna fish, comprising continuously feeding, for at least 60 days, a compound feed comprising an inclusion containing fish meal and fats and an exoskeleton which encases the inclusion and is at least one heat-gel selected from the group consisting of proteins and polysaccharides, the compound feed having a vitamin E content of 500 ppm or more relative to the total feed.

The present invention provides farmed tuna fish enriched in vitamin E, uses thereof, and a method for raising the same.

FIG. 1 is a schematic diagram of a cross section of a fish body showing the location where fish meat was harvested in the embodiment.

In this specification, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. In this specification, a numerical range indicated using "~" indicates a range that includes the numerical values before and after the range as the minimum and maximum values, respectively.
In this specification, the terms "less than" or "less than" in relation to percentages mean a range including 0% i.e. "not contained" or a value that is undetectable by current means, unless a lower limit is specifically stated. In this specification, the amount of each component in a composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified.
The present invention will now be described.

<Farmed tuna fish>
In one embodiment of the present invention, at least one selected from the group consisting of muscle, liver, and eyeballs of a farmed tuna fish contains 2 mg or more of vitamin E per 100 g. In this specification, this farmed tuna fish may be referred to as a "vitamin E-enriched farmed fish."
Generally, the vitamin E content of farmed piscivorous fish is known to be about 1-2 mg per 100 g of edible portion in yellowtail, about 4 mg per 100 g of yellowtail (farmed), and about 3 mg per 100 g of swordfish, according to the Standard Tables of Food Composition in Japan, 2010. On the other hand, the vitamin E content of tuna (fatty meat) is lower than these fish species, with a content of 1.5 mg per 100 g.

In contrast, the present farmed tuna fish contains 2 mg or more of vitamin E per 100 g in at least one selected from the group consisting of muscle, liver, and eyeballs. Farmed tuna fish with tissues containing such a high amount of vitamin E have not been identified until now.

Therefore, the farmed tuna fish of the present invention contain vitamin E at a much higher concentration than conventional tuna fish, and each tissue can exhibit the high physiological action of vitamin E specific to that tissue. In addition, the farmed tuna fish of the present invention accumulate vitamin E at a much higher concentration in each tissue than conventional farmed tuna fish, so that in a rearing environment, due to the immune-activating effect of vitamin E or the inhibition of lipid peroxide production due to its antioxidant effect, it is expected that the fish will be resistant to feeding restrictions, have a high survival rate, be resistant to stress, and be less susceptible to disease. When the edible parts of such farmed tuna fish are used as food, it can be assumed that the antioxidant power of vitamin E will make the meat less likely to become burnt, and furthermore, since a larger amount of vitamin E can be ingested with a smaller amount, the efficacy of vitamin E can be expected to be efficiently exerted.

Tuna, a farmed fish enriched with vitamin E, is generally known to contain relatively large amounts of functional unsaturated fatty acids such as docosahexaenoic acid (DHA). Since farmed fish enriched with vitamin E contain a large amount of vitamin E, oxidation of the functional unsaturated fatty acids can be suppressed.
Examples of tunas include the Thunnus family and the Bonito family. Examples of the Thunnus family include the genus Thunnus, the genus Bonito, the genus Scutellaria, and the genus Bonito, and examples of the Bonito family include the genus Dogtooth tuna and the genus Bonito. Examples of tunas include albacore, bluefin tuna, southern bluefin tuna, Atlantic bluefin tuna, yellowfin tuna, bigeye tuna, and longfin tuna of the genus Thunnus, skipjack tuna of the genus Bonito, flathead tuna and roundhead tuna of the genus Scutellaria, and shortfin tuna of the genus Scutellaria, and skipjack tuna of the genus Bonito, or albacore, bluefin tuna, southern bluefin tuna, Atlantic bluefin tuna, yellowfin tuna, bigeye tuna, longfin tuna, bonito, or shortfin tuna.

The vitamin E-enriched farmed fish is preferably a tuna species that can feed primarily on fish native to the Northern Hemisphere. Such tuna species that can feed primarily on fish native to the Northern Hemisphere include albacore, bluefin tuna, Atlantic bluefin tuna, yellowfin tuna, bigeye tuna, longfin tuna, bonito, and spotted tuna.

The vitamin E-enriched farmed fish may be obtained by any method, and it is preferable that the fish be obtained by raising and managing them with a feed containing a compound feed.
"Formulated feed" means feed made up of a combination of ingredients that meets the protein, vitamins, minerals, and other nutrients required for the growth of fish. "Raising and managing" means that fish are raised using feed selected to achieve a specific purpose.

In the vitamin E-enriched farmed fish, at least one selected from the group consisting of muscle, liver, and eyeballs contains 2 mg or more of vitamin E per 100 g, and preferably contains 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, 20 mg or more, 30 mg or more, 50 mg or more, 80 mg or more, 100 mg or more, or 150 mg or more of vitamin E. The vitamin E-enriched farmed fish may be at least one selected from the group consisting of muscle, liver, and eyeballs, and may contain 2 mg or more of vitamin E per 100 g in a part thereof. There is no particular limit to the upper limit of the vitamin E content in at least one tissue selected from the group consisting of muscle, liver, and eyeballs of the vitamin E-enriched farmed fish, and it may be, for example, 1000 mg or less.

Examples of muscles include dorsal muscles, ventral muscles, dorsal keel muscles, ventral keel muscles, and dark muscles. The dorsal muscles, ventral muscles, dorsal keel muscles, and ventral keel muscles are located relatively deep in the body of the fish and can be divided into red meat, which has a higher myoglobin content and a reddish color, and fat meat, which is located relatively shallow in the body of the fish and has a lower myoglobin content and a lighter red color. Fatty meat is sometimes also known as "fatty tuna," and is called "otoro" (fatty tuna) or "chutoro" (fatty tuna) depending on the amount of fat. Dark muscles are the reddish-brown muscles near the junction of the dorsal and ventral muscles.

The vitamin E content is measured as follows. In the case of muscle, a part of the muscle is cut into a size of, for example, about 5 cm square, and used as a test piece. In the case of liver, a part of the liver, for example, the central part is cut into a size of 5 cm x 5 cm, and used as a test piece. In the case of eyeball, the eyeball and optic nerve are removed, finely chopped, and used as a test piece.
The amount of vitamin E in the test piece is quantified by high performance liquid chromatography (HPLC) (fluorescence spectrophotometer) using unsaponifiable matter extracted by alkaline saponification as a sample. That is, alkaline saponification is performed using a sodium chloride solution, a pyrogallol-ethanol solution, and a potassium hydroxide solution, followed by shaking extraction using a mixture of sodium chloride solution, hexane, and ethyl acetate, and the upper layer is separated, the solvent is distilled off, and then added to hexane to prepare a measurement sample, which is quantified based on the peak ratio in HPLC.

Examples of vitamin E include tocopherols and tocotrienols, specifically α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol, δ-tocotrienol, etc. Vitamin E-enriched farmed fish can contain these vitamins E alone or in combination of two or more types.

Preferably, the vitamin E-enriched farmed fish contains vitamin E in any two of the muscle, liver and eyeballs, i.e., the muscle and eyeballs, the muscle and liver, or the liver and eyeballs, more preferably in any of the muscle, liver and eyeballs, at a concentration of 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, or 15 mg or more per 100 g. It can be assumed that such vitamin E-enriched farmed fish has a high vitamin E content in multiple tissues. There is no particular limit to the upper limit of the vitamin E content of the vitamin E-enriched farmed fish, and it can be, for example, 1000 mg or less, 300 mg or less.

Vitamin E-enriched farmed fish can contain 2 mg or more, 5 mg or more, 8 mg or more, or 10 mg or more of vitamin E per 100 g of muscle. There is no particular limit to the upper limit of the vitamin E content in the muscle of vitamin E-enriched farmed fish, and it can be, for example, 1000 mg or less, 300 mg or less, 100 mg or less, or 50 mg or less. Such vitamin E-enriched farmed fish with muscles that have a high vitamin E content can, for example, exercise for long periods of time without getting tired easily, and can suppress the occurrence of so-called burnt meat.

Vitamin E-enriched farmed fish can contain 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, 20 mg or more, 30 mg or more, 50 mg or more, 80 mg or more, 100 mg or more, or 150 mg or more of vitamin E per 100 g of liver. There is no particular limit to the upper limit of the vitamin E content in the liver of vitamin E-enriched farmed fish, and it can be, for example, 1000 mg or less, or 300 mg or less. Such vitamin E-enriched farmed fish with livers with a high vitamin E content can maintain the digestive ability of farmed tuna fish for a longer period of time, and can maintain their health for a longer period of time through more sustained nutrient absorption.

The vitamin E enriched farmed fish can contain 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, or 20 mg or more of vitamin E per 100 g of eyeball. There is no particular limit to the upper limit of the vitamin E content in the eyeball of the vitamin E enriched farmed fish, and it can be, for example, 1000 mg or less, 300 mg or less, 100 mg or less, or 50 mg or less. The vitamin E enriched farmed fish having such eyeballs with a high vitamin E content can, for example, improve peripheral circulatory disorders, prevent an increase in lipid peroxides, improve retinal metabolic abnormalities, etc., and therefore, are less likely to suffer from eye fatigue and can have improved feeding ability, or can easily avoid collisions with obstacles due to improved vision of the farmed fish.

Preferably, the vitamin E-enriched farmed fish contains α-tocopherol in any two of the muscle, liver and eyeballs, i.e., the muscle and eyeballs, the muscle and liver, or the liver and eyeballs, more preferably in any of the muscle, liver and eyeballs, at a concentration of 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, or 15 mg or more per 100 g. It can be assumed that such vitamin E-enriched farmed fish has a high vitamin E content in the entire fish body. There is no particular limit to the upper limit of the α-tocopherol content in vitamin E-enriched farmed fish, and it can be, for example, 1000 mg or less, or 300 mg or less.

Vitamin E-enriched cultured fish can contain α-tocopherol in an amount of 2 mg or more, 5 mg or more, 8 mg or more, or 10 mg or more per 100 g of muscle. There is no particular upper limit to the amount of α-tocopherol contained in the muscle of vitamin E-enriched cultured fish, and the upper limit can be, for example, 1000 mg or less, 300 mg or less, 100 mg or less, or 50 mg or less. Such vitamin E-enriched cultured fish having muscles with a high α-tocopherol content can, for example, exercise for a long period of time without getting tired easily, and can suppress the occurrence of so-called burnt meat.
The vitamin E-enriched farmed fish may contain α-tocopherol in an amount of 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, 20 mg or more, 30 mg or more, 50 mg or more, 80 mg or more, 100 mg or more, or 150 mg or more per 100 g of liver. There is no particular limit to the upper limit of the α-tocopherol content in the liver of the vitamin E-enriched farmed fish, and it may be, for example, 1000 mg or less, or 300 mg or less. The vitamin E-enriched farmed fish having such a liver with a high α-tocopherol content can maintain the digestive ability of, for example, farmed tuna fish for a longer period of time, and can maintain their health for a longer period of time due to more sustained nutrient absorption.

The vitamin E-enriched farmed fish can contain α-tocopherol in an amount of 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, or 20 mg or more per 100 g of eyeball. There is no particular limit to the upper limit of the α-tocopherol content in the eyeball of the vitamin E-enriched farmed fish, and it can be, for example, 1000 mg or less, 300 mg or less, 100 mg or less, or 50 mg or less. The vitamin E-enriched farmed fish having such eyeballs with a high α-tocopherol content can, for example, improve peripheral circulatory disorders, prevent an increase in lipid peroxides, improve retinal metabolic abnormalities, etc., and therefore are less susceptible to eye fatigue and can have improved feeding ability, or can improve the eyesight of the farmed fish, making it easier to avoid collisions with obstacles.

The vitamin E-enriched cultured fish can have a fatness index of preferably 20 or more, more preferably 21 or more, and even more preferably 22 or more. Compared with wild fish, vitamin E-enriched cultured fish with a fatness index of 20 or more can be said to be fatty, and can provide a larger amount of edible parts enriched in vitamin E.
The degree of obesity can generally be evaluated based on the following formula [1]:
Obesity level =
Weight (g)/[Fork length (cm) x Fork length (cm) x Fork length (cm)] x 1000
...[1]

The vitamin E enriched farmed fish can have a fork length of 90 cm or more, 100 cm or more, 120 cm or more, 150 cm or more, or 200 cm or more. The vitamin E enriched farmed fish with a fork length of 90 cm or more are larger than wild fish and can provide more edible parts enriched in vitamin E. The fork length refers to the distance from the tip of the fish's head to the end of the center of the fin, and is an indicator of external morphology well known to those skilled in the art. The fork length is measured by measuring the linear distance in a plan view from the tip of the fish's head to the end of the center of the fin. There is no particular limit to the upper limit of the fork length of vitamin E enriched farmed fish, and it can be, for example, 2000 cm or less.

In the case of vitamin E-enriched farmed fish of individual fish, the weight of the whole fish, i.e., the total fish body weight, of the vitamin E-enriched farmed fish is preferably 20 kg or more, more preferably 25 kg or more, even more preferably 30 kg or more, even more preferably 35 kg or more, and particularly preferably 40 kg or more. Vitamin E-enriched farmed fish with a heavier total fish weight have the advantages of being able to obtain more edible parts enriched in vitamin E, and because more fat is included, the difference between the fat and the lean parts is more pronounced, and therefore more fat that is less oxidized due to the antioxidant power of vitamin E can be obtained.
There is no particular upper limit on the total weight of vitamin E-enriched farmed fish, and it can be, for example, 500 kg or less.

Farmed fish enriched in vitamin E can have parts with a higher vitamin E content than farmed fish that are not enriched in vitamin E. In farmed fish enriched in vitamin E, the parts with a higher vitamin E content can exhibit good function because the production of lipid peroxides and the like is suppressed by the enriched vitamin E.

A vitamin E-enriched cultured fish can have a larger pyloric caeca than fish that are not enriched with vitamin E. For example, the relative pyloric caeca weight of the vitamin E-enriched cultured fish can be 2% or more. In fish, the pyloric caeca is a nutrient absorption organ, so when the size of the pyloric caeca is large, it is expected that the nutrient absorption is relatively large. When the vitamin E-enriched cultured fish is raised using a compound feed, the relative pyloric caeca weight tends to be larger than that of cultured fish other than the vitamin E-enriched cultured fish. The ratio of the weight of the pyloric caeca to the total fish weight in the vitamin E-enriched cultured fish, i.e., the relative pyloric caeca weight, may be 2% or more, 2.5% or more, 3% or more, or 3.5% or more. There is no particular limit to the upper limit of the relative pyloric caeca weight of the vitamin E-enriched cultured fish, and it can be, for example, 10% or less.
Since vitamin E-enriched farmed fish with a high relative pyloric caeca weight have relatively good nutrient absorption, when one or more other nutrients that can accumulate in the edible parts are contained in the compound feed, it is expected that these other nutrients will accumulate to a high degree. The weight of the pyloric caeca can be measured by obtaining the pyloric caeca by separating it from the internal organs removed from the fish body.

The pyloric caeca of vitamin E-enriched farmed fish can contain 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, 20 mg or more, 30 mg or more, 50 mg or more, or 80 mg or more of vitamin E per 100 g. When the vitamin E content in the pyloric caeca is high, it is expected that the function of the pyloric caeca will be effectively exerted based on the antioxidant power of vitamin E. There is no particular limit to the upper limit of the vitamin E content in the pyloric caeca of vitamin E-enriched farmed fish, and it can be, for example, 500 mg or less.

In addition to the above, vitamin E-enriched farmed fish may have tissues or organs with a vitamin E content of 2 mg or more. Examples of tissues or organs with high vitamin E content that may be found in vitamin E-enriched farmed fish include the stomach, esophagus, intestines, testes, ovaries, spleen, heart, and blood.

The forms of vitamin E-enriched farmed fish include a form that includes all parts from the head to the tail, i.e., an "individual fish," and a "processed form" in which parts of the individual fish body have been removed.
Examples of processed vitamin E-enriched farmed fish include those from which at least one part selected from the group consisting of gills, internal organs, tail, and head has been removed. Examples of internal organs include the esophagus, stomach, intestines, liver, pyloric caeca, testes, ovaries, pancreas, heart, swim bladder, etc. The processed form is appropriately selected depending on the convenience of distribution, and examples include a form from which the gills and internal organs have been removed. Tuna from which the gills and internal organs have been removed is generally called GG tuna. In other words, "GG tuna" refers to a form from which the gills and internal organs, specifically the esophagus, stomach, intestines, liver, pyloric caeca, gonads (testes or ovaries), spleen, heart, and swim bladder have been removed.

It is known that the weight of GG tuna is equivalent to about 85-89% of the total fish body weight. In one embodiment of the present invention, the weight of GG tuna is preferably 17 kg or more, more preferably 21 kg or more, even more preferably 26 kg or more, and even more preferably 34 kg or more. The heavier the weight, the more advantageous it is that a greater amount of edible parts enriched in vitamin E can be obtained, and because more fat is added, the difference between the fat and the lean parts becomes more pronounced, and the antioxidant power of vitamin E makes it possible to obtain more fat that is less likely to be oxidized. The length of GG tuna is almost the same as the fork length of the above-mentioned vitamin E-enriched farmed fish, that is, GG tuna can have a length of 90 cm or more, 100 cm or more, or 120 cm or more. GG tuna with a length of 90 cm or more is larger than wild fish, and can provide more edible parts enriched in vitamin E.

Other processed forms include, for example, the so-called headless form, in which the head and tail are further removed from GG tuna, and the so-called loin form, in which the headless form is divided into left and right and dorsal and ventral sides and cut into four pieces.

A processed form of vitamin E-enriched farmed fish from which at least one part selected from the group consisting of gills, internal organs, and head has been removed can have muscle, eyeballs, or both muscle and eyeballs. The muscle of a processed form of vitamin E-enriched farmed fish can contain 2 mg or more, 5 mg or more, 8 mg or more, or 10 mg or more of vitamin E per 100 g, as in the case of individual fish. The eyeball of a processed form of vitamin E-enriched farmed fish can contain 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, or 20 mg or more of vitamin E per 100 g, as in the case of individual fish.

Examples of vitamin E enriched farmed fish according to one embodiment of the present invention include the following:
(1) A vitamin E-enriched farmed fish containing 5 mg, 8 mg, or 10 mg or more of vitamin E per 100 g of muscle, with a fatness index of 21 or more, a total fish weight of 25 kg or more, and a fork length of 90 cm or more; (2) A vitamin E-enriched farmed fish containing 5 mg, 8 mg, or 10 mg or more of vitamin E per 100 g of muscle, with a fatness index of 20 or more, a total fish weight of 20 kg or more, and a fork length of 100 cm or more;
(3) Vitamin E-enriched farmed fish that is a GG tuna containing 5 mg, 8 mg, or 10 mg or more of vitamin E per 100 g of muscle, with an obesity index of 21 or more, a total fish weight of 21 kg or more, and a fork length of 90 cm or more; and
(4) Vitamin E-enriched farmed fish that is a GG tuna containing 5 mg, 8 mg, or 10 mg or more of vitamin E per 100 g of muscle, with a fatness index of 20 or more, a total fish weight of 17 kg or more, and a fork length of 100 cm or more:

(5) Vitamin E-enriched farmed fish containing 50 mg, 80 mg, or 100 mg or more of vitamin E per 100 g of liver, having a fatness index of 21 or more, a total fish weight of 25 kg or more, and a fork length of 90 cm or more;
(6) Vitamin E-enriched farmed fish containing 50 mg, 80 mg, or 100 mg or more of vitamin E per 100 g of liver, having a fatness index of 20 or more, a total fish weight of 20 kg or more, and a fork length of 100 cm or more;
(7) Vitamin E-enriched farmed fish that is a GG tuna containing 50 mg, 80 mg, or 100 mg or more of vitamin E per 100 g of liver, with an obesity index of 21 or more, a total fish weight of 21 kg or more, and a fork length of 90 cm or more; and
(8) Vitamin E-enriched farmed fish that is a GG tuna containing 50 mg, 80 mg, or 100 mg or more of vitamin E per 100 g of liver, with a fatness index of 20 or more, a total fish weight of 17 kg or more, and a fork length of 100 cm or more:

(9) Vitamin E-enriched farmed fish containing 10 mg, 15 mg, or 20 mg or more of vitamin E per 100 g of eyeball, having a fatness index of 21 or more, a total fish weight of 25 kg or more, and a fork length of 90 cm or more;
(10) Vitamin E-enriched farmed fish containing 10 mg, 15 mg, or 20 mg or more of vitamin E per 100 g of eyeball, having a fatness index of 20 or more, a total fish weight of 20 kg or more, and a fork length of 100 cm or more;
(11) Vitamin E-enriched farmed fish that is a GG tuna containing 10 mg, 15 mg, or 20 mg or more of vitamin E per 100 g of eyeball, with an obesity index of 21 or more, a total fish weight of 21 kg or more, and a fork length of 90 cm or more; and
(12) A vitamin E-enriched farmed fish that is a GG tuna containing 10 mg, 15 mg or 20 mg or more of vitamin E per 100 g of eyeball, with an obesity index of 20 or more, a total fish weight of 17 kg or more, and a fork length of 100 cm or more.

The vitamin E-enriched farmed fish of (1) to (12) are less susceptible to disease, and even when used as food, they are enriched in vitamin E and can exhibit better properties.
The muscle-related forms (1) to (4), the liver-related forms (5) to (8), and the eyeball-related forms (9) to (12) may be independently combined with each other to the extent possible.

In the vitamin E-enriched farmed fish of (1), (2), (5), (6), (9), and (10), the relative pyloric caeca weight may be 2% or more, 2.5% or more, 3% or more, or 3.5% or more. In the vitamin E-enriched farmed fish of (1), (2), (5), (6), (9), and (10), the pyloric caeca may be 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, 20 mg or more, 30 mg or more, 50 mg or more, or 80 mg or more per 100 g. Furthermore, in the vitamin E-enriched farmed fish of (1), (2), (5), (6), (9), and (10), the relative pyloric caeca weight and vitamin E content described above may be combined.

<Edible parts and food>
One embodiment of the present invention includes an edible portion of a farmed tuna fish, which is an edible portion of a tuna fish containing 2 mg or more of vitamin E per 100 g. In other words, the edible portion of the farmed tuna fish may be the edible portion of the vitamin E-enriched farmed fish described above. The edible portion of the vitamin E-enriched farmed fish contains vitamin E at a much higher concentration than the edible portions of tuna fish known in the art, and is therefore expected to have high economic value and exhibit the efficacy of vitamin E when provided as food.

"Edible parts" refers to any part of a fish that can be consumed, such as fish meat, internal organs, eyeballs, skin, brain, blood, etc. In the case of tissues or organs, it may be the entire tissue or organ or even a part of it. For example, in the case of the liver, it may be the entire liver or a part of it.

The edible part may be fish meat, internal organs or eyeballs.
The edible part of fish meat is muscle, and is generally eaten either uncooked (raw) or cooked. Examples of fish meat include the above-mentioned lean meat, fatty meat, dark muscle, etc., and lean meat or fatty meat is preferred.

Edible internal organs include the liver, pyloric caeca, stomach, esophagus, intestines, gonads (testes or ovaries), spleen, heart, swim bladder, etc. These internal organs can generally be cooked and eaten. The eyeballs as edible parts may have the surrounding muscles attached.

As described above, the edible parts of the farmed tuna fish in one embodiment of the present invention are edible parts of vitamin E-enriched farmed fish, so the matters already described for vitamin E-enriched farmed fish apply as is to the vitamin E content in the edible parts of the fish meat, liver, pyloric caeca, and eyeballs. The matters already described for vitamin E-enriched farmed fish apply as is to the extent possible to other parts as edible parts. For example, the vitamin E content in other edible parts can be 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, 20 mg or more, 30 mg or more, 50 mg or more, 80 mg or more, 100 mg or more, or 150 mg or more per 100 g.

The edible parts of farmed tuna fish may include fish meat, internal organs, or parts around the eyes. For example, the "edible parts" of the present invention also include "crude" (aru). Crude generally means the head, bones, gills, fins, or a combination of two or more of these that remain after the fish is filleted and the flesh removed, along with the meat and skin attached to these. In the case of crude, the part remaining after removing the bones contained in the crude should contain 2 mg or more, 5 mg or more, 8 mg or more, 10 mg or more, 15 mg or more, or 20 mg or more of vitamin E per 100 g.

The edible parts of farmed tuna fish are preferably used as food, for example, the following heated and non-heated foods, and can also be used as animal feed. The food and animal feed according to one embodiment can include the edible parts of farmed tuna fish. According to the present invention, it is possible to provide food and animal feed that are resistant to denaturation and have a reduced oxidized odor due to the antioxidant power of vitamin E. The food and animal feed according to one embodiment contain vitamin E at a concentration far higher than that of the edible parts of tuna fish known in the art, so that when provided as food, it is expected to have high economic value and to exert the efficacy of vitamin E. Examples of animal feed include cat food, dog food, and farmed fish feed. The animal feed may be contained in a container described below. Examples of food include non-heated food and heated food.

One embodiment of the present invention includes an unheated food product comprising edible parts of vitamin E-enriched farmed fish and a container for housing the edible parts. Unheated products refer to edible parts that have not been cooked with heat, and examples of such products include minced fish, sashimi, fillets, blocks, and fillets, as well as frozen, chilled, freeze-dried, dried, and pickled products. The fact that the product has not been cooked with heat can be determined by the color tone of the surface of the edible parts. In this specification, "heating" means that heat is applied to a state in which actomyosin is denatured to a degree that is visible. When edible parts of farmed fish are subjected to heat treatment, the edible parts discolor due to the denaturation of actomyosin, so it can be determined based on the discoloration of the edible parts.

One embodiment of the present invention includes a heated food product that includes a heated product of edible parts of vitamin E-enriched farmed fish and a container that contains the heated product. The heated product means the edible parts that have been subjected to cooking, and examples of the heated product include simmered foods, baked foods, steamed foods, fried foods, and paste products.

The shapes of the heated and non-heated products are not particularly limited, and may have a shape specific to the edible part, may be irregularly shaped by shredding, or may be molded into a specific shape.
The heated food and the non-heated food may contain at least one selected from the group consisting of other foods, food ingredients, and accessories, as necessary. Examples of other foods include rice, tsuma (Japanese radish, seaweed, etc.), ginger, etc. Examples of food ingredients include green onions for negitoro. Examples of accessories include, for example, balancers, labels, ice packs, cooling agents, ice, dry ice, sherbet ice, etc. The accessories may be contained in the container together with the edible part, or may be disposed outside the container, or may be integrally and inseparably attached to the container, or may be detachably attached. Each of the other foods, food ingredients, and accessories may be one or a combination of two or more.

The container may be any material that can be used to contain the edible portion, such as polystyrene foam, paper, vinyl, soft plastic, hard plastic, metal, or glass. The shape of the container may be any material that can contain the edible portion, such as a packaging sheet, a tray with or without a lid, a bag, or a can.

The above-mentioned vitamin E-enriched farmed fish, the edible parts of the above-mentioned vitamin E-enriched farmed fish, and the vitamin E-enriched farmed fish for the non-heated product and heated product of the edible parts may be obtained by any method. The vitamin E-enriched farmed fish is preferably a vitamin E-enriched farmed fish produced by the following breeding method.

<Breeding method>
The rearing method in one embodiment of the present invention includes continuously feeding tuna as a farmed fish for at least 60 days a compound feed comprising an inclusion containing fish meal and fats and an outer skin which encases the inclusion and is at least one heat gel selected from the group consisting of proteins and polysaccharides, the inclusion having a vitamin E content of 500 ppm or more relative to the entire feed, and may include other steps as necessary.
In this rearing method, a double-structure compound feed having a specific inclusion containing vitamin E and a specific outer skin is continuously fed to tunas for at least 60 days, making it possible to efficiently obtain vitamin E-enriched cultured fish according to an embodiment of the present invention that are enriched in vitamin E. From this perspective, in this specification, the term "method for rearing vitamin E-enriched cultured fish" is synonymous with the term "method for producing vitamin E-enriched cultured fish", and they can be read interchangeably.

The compound feed used in the breeding method of this embodiment has a double structure including an outer shell and an inner shell containing vitamin E. In this specification, this compound feed used in the breeding method of this embodiment may be referred to as vitamin E-enriched farmed fish feed.
The vitamin E enriched farmed fish feed contains fish meal and oil as main ingredients, a predetermined amount of vitamin E, and may further contain other nutritional components other than vitamin E that are known as nutritional components for farmed fish. Examples of other nutritional components include minerals and vitamins such as vitamin C.

Examples of vitamin E contained in the capsule include tocopherol and tocotrienol, as well as derivatives thereof. Examples of tocopherol and its derivatives include α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, and carboxylic acid esters thereof, such as α-tocopherol acetate, α-tocopherol nicotinate, α-tocopherol linoleate, and α-tocopherol succinate. As the tocopherol, a mixture of these, i.e., mixed tocopherol, can be used. Examples of tocotrienol and its derivatives include α-tocotrienol, β-tocotrienol, γ-tocotrienol, δ-tocotrienol, and acetate esters thereof.

The vitamin E content is preferably 500 ppm or more of the total weight of the compound feed, more preferably 550 ppm or more, and even more preferably 600 ppm or more. There is no particular upper limit to the vitamin E content, but it can be, for example, 20% by weight or less of the total weight of the compound feed.

The encapsulation can be stabilized by blending polysaccharides, hardened oils, etc., and emulsifying them. This can prevent the leakage of fish meal or liquid oils and fats. When compound feed is produced by machine, it is preferable that the physical properties of the encapsulation are fluid or physical properties that are suitable for machinery. Examples of oil and fat adsorbents include Oil Q (manufactured by Nippon Starch Chemical Co., Ltd.), hardened oils include Unishort K (manufactured by Fuji Oil Co., Ltd.), and emulsifiers include New Fujipro SEH (manufactured by Fuji Oil Co., Ltd.).

Raw materials used in conventional compound feed for farmed fish can be added to the encapsulation. Examples include proteins such as raw fish, squid meal, krill meal, soybean oil meal, and corn gluten meal, oils and fats such as krill oil, whale oil, soybean oil, corn oil, rapeseed oil, and hardened oil, starches such as starch, wheat flour, rice flour, tapioca flour, and corn flour, polysaccharides such as alginic acid and its salts, sodium carboxymethylcellulose (CMC), guar gum, dextrin, chitosan, curdlan, pectin, carrageenan, mannan, gellan gum, gum arabic, and edible water-soluble cellulose, vitamins, and minerals.

The inclusions can be formulated so that the oil content is 20-70% by weight of the total weight of the inclusions, and particularly when feeding large farmed fish, the oil content is preferably 30% by weight or more, more preferably 35% by weight or more, and most preferably 45% by weight or more. A large amount of oil content can have an excellent effect on the growth and growth efficiency of farmed fish, and if it is 70% by weight or less, it becomes easy to select and incorporate other preferred ingredients. Fish oil and other vegetable oils can be used as they are, or preferably, Vitacel (registered trademark, the same applies below) WF200, Vitacel WF600 or Vitacel WF600/30 (manufactured by Rettenmeyer), Oil Q No. The fluidity can be reduced by using oil-absorbing polysaccharides such as dextran, such as Oil Q-S (manufactured by Nippon Starch Chemical Co., Ltd.), Pine Flow (manufactured by Matsutani Chemical Co., Ltd.), oil-absorbing proteins such as fermented soybeans and isoflavones, or hardened oils obtained by hydrogenating fats and oils such as soybean oil, rapeseed oil, or palm oil. Fish oil can also be used by reducing its fluidity through emulsification. From the viewpoint of fish digestibility, it is desirable that these components that reduce fluidity be 10% by weight or less, more preferably 5% by weight or less, of the total weight of the encapsulation. Fish oil is the most preferable fat and oil. Fish oil can also be partially replaced with other vegetable fats and oils.

As the fish meal, which is an essential component of the encapsulation, various fish meals commonly used as raw materials for fish feed, powder of crustaceans such as krill, etc. can be used. The fish meal content can be 30 to 70% by weight of the total weight of the encapsulation, preferably 30% by weight or more, more preferably 35% by weight or more, and most preferably 45% by weight or more. From the viewpoint of maintaining the shape, it is preferable to add excipients such as polysaccharides with binding properties, hardened oils, and emulsifiers to the encapsulation.

The outer shell of the vitamin E-enriched farmed fish feed is a heat-induced gel obtained from at least one raw material selected from the group consisting of proteins and polysaccharides. A raw material containing a protein raw material and/or a polysaccharide raw material that forms a gel when heated (hereinafter referred to as the outer shell composition) is used. The outer shell composition gels when heated and exhibits a certain degree of elasticity, extensibility, and adhesion. By using such a heat-induced gel, the inclusions are reliably enveloped.
A gel produced by heating means a gel produced by heating at least one raw material selected from the group consisting of proteins and polysaccharides to 60°C or higher, or by heating to 60°C or higher and then cooling, and a gel produced by gelatinizing polysaccharides such as starch by adding moisture and heating to 60°C or higher.

The outer shell is not particularly limited as long as it can encase the inclusion. The protein applied to the outer shell is preferably a protein having gel-forming ability, such as a single protein such as fish meat, minced fish, krill, gluten, collagen, soy protein, enzymatically decomposed soy protein, gelatin, egg white, or a mixture of two or more of these proteins. The protein also includes alginic acid and its salts. Examples of polysaccharides include starch, alginic acid and its salts, sodium carboxymethylcellulose (CMC), guar gum, dextrin, chitosan, curdlan, pectin, carrageenan, mannan, gellan gum, gum arabic, edible water-soluble cellulose, etc.
Preferred starches for use in the outer shell include tapioca starch, wheat starch, potato starch, corn starch, soybean starch, waxy corn starch, and modified starches thereof. Food materials containing a large amount of these proteins and/or starches can also be used. The outer shells containing these proteins and/or polysaccharides have a gel that is fixed by heating, are flexible, and have a certain strength because they retain the inner layer composition. Among these, gels formed by heating proteins or gels formed by heating starch are preferred in terms of physical properties such as flexibility and extensibility.

For example, when using fish paste as the raw material, it can be produced using the general method for producing kamaboko and other paste products. Specifically, 2% by weight or more of salt is added, and the mixture is left at 10°C or higher, preferably 30°C to 40°C, for 10 minutes or more, and then heated at 80°C to 90°C for 10 minutes or more. When using egg white, for example, a composition with the desired physical properties can be obtained by mixing egg white:starch:fish meal:water in a weight ratio of 1:1:2:6 and heating.

Various auxiliary materials can be added to the composition for skin application as long as they do not affect the formation of the gel.
Fish meal or oils and fats may also be added to the composition for skins to the extent that the gelation of the skins is not affected. In the case of fish meal, the skins can contain up to about 60% by weight of fish meal, and in the case of oils and fats, the skins can contain up to 30% by weight of oils and fats based on the total weight of the composition for skins, depending on the type of gel used. When both fish meal and oils and fats are included, the skins preferably contain about 20 to 30% by weight of fish meal and about 5 to 10% by weight of oils and fats based on the total weight of the composition for skins.

To improve the quality of the gel in the outer skin, additives used as quality improvers in fish paste products and the like can be added to the outer skin composition. Examples of additives include starch, thickening polysaccharides, isolated soy protein, sodium bicarbonate, polymerized phosphate, egg white, transglutaminase, and various protease inhibitors. In particular, the outer skin can contain thickeners such as agar, gellan gum, pullulan, starch, mannan, carrageenan, xanthan gum, locust bean gum, curdlan, pectin, alginic acid and its salts, gum arabic, chitosan, dextrin, and edible water-soluble cellulose to enhance the gel strength.

Another preferred embodiment of the outer shell is a heated gel mainly composed of starch, which is excellent in terms of elasticity and flexibility. A gel obtained by adding water to starch, kneading the mixture, and heating it can exhibit good elasticity, flexibility, and extensibility. In particular, various types of processed starch each have their own characteristics, and by combining two or more types, an outer shell having better properties such as elasticity, flexibility, and extensibility can be obtained. For example, it is preferable to combine different types of processed starch, such as a combination of etherified starch and phosphate cross-linked starch.
A stronger gel can be obtained by adding proteins such as gluten and soy protein to starch. Instead of gluten, wheat flour containing gluten can be used. Other auxiliary ingredients include cereal flour such as wheat flour; proteins such as soy protein, gluten, and egg white; sugars or sugar alcohols such as sugar and starch syrup; thickeners such as carrageenan, agar, gellan gum, pullulan, mannan, xanthan gum, locust bean gum, curdlan, pectin, alginic acid and its salts, gum arabic, chitosan, dextrin, and edible water-soluble cellulose; and salts such as phosphates. For example, adding wheat flour to starch can give strength to the outer skin. Also, adding a certain amount of protein can suppress the stickiness of the surface after heating.

The starch in the outer skin is not particularly limited, but tapioca starch, wheat starch, potato starch, corn starch, soybean starch, etc. can be used, and processed starches such as etherified, acetylated, acetyl-crosslinked, ether-crosslinked, phosphate-crosslinked, and alpha-hydroxypropyl phosphate-crosslinked starches are particularly preferred. In particular, the outer skin of the vitamin E-enriched farmed fish feed contains a combination of tapioca starch acetate and etherified tapioca starch. In the case of such vitamin E-enriched farmed fish feed, this is preferred from the viewpoints of suppressing stickiness of the surface and making the feed easy to eat. The combination of tapioca starch acetate and etherified tapioca starch can be, for example, 1:1 to 1:20 by weight, preferably 1:2 to 1:15, and more preferably 1:8 to 1:12.

Vitamin E enriched farmed fish feed can be produced by adding water to a composition for the outer skin, which is made by adding starch, the raw material for the outer skin, to other auxiliary ingredients such as protein, mixing and kneading the mixture, wrapping the contents in a wrapping machine, and then heating the mixture.

Preferably, the composition for the outer shell and the inclusion are separately supplied to a double nozzle extruder, and the composition for the outer shell is mixed and heat-treated while being extruded in such a way that the inclusion is wrapped in the outer shell, and the method may include other steps as necessary.
For example, an extruder equipped with a double nozzle can be used to heat the composition for the outer shell by extrusion cooking and to coat the inner encapsulation with the outer shell at the same time; for example, a cylindrical extruded product can be cut to a certain length by a shutter mechanism that moves up and down in accordance with the speed of extrusion, and the cut surfaces can be covered with the outer shell to obtain a double-structured compound feed.

The device suitable for obtaining such a double-structure compound feed with a double nozzle may be either single-shaft or twin-shaft, as long as it has an extrusion mechanism and a heating mechanism. The device suitable for obtaining a double-structure compound feed is preferably a co-rotating intermeshing twin-shaft type device. When such a device is used, it is possible to obtain advantages such as sufficient mixing in a short time. An example of such a device is one manufactured by Buhler, and is disclosed, for example, in WO 2013/061892.

This device is equipped with an extruder with a heating function connected to a composition supplying device for outer skin, and a nozzle that sends the encapsulation to the center of the composition for outer skin is arranged near the discharge port of the extruder. An encapsulation supplying device is connected to this nozzle. A conveyor is adjacent to the extruder, and a shutter mechanism is arranged at the end of the conveyor's transport path. The composition supplying device for outer skin mixes the composition for outer skin and sends it to the extruder with a pump. The encapsulation supplying device pumps the encapsulation that has been mixed and produced separately from the nozzle to the discharge port of the extruder. The composition for outer skin is kneaded in the extruder and then heated to become a heated gel. At the discharge port, the outer skin is extruded into a cylindrical shape, its inside is filled with the encapsulation inserted from the nozzle, and it is discharged in the form of a double-structured column. The discharged double-structured columnar object is transported by a conveyor and inserted vertically downward into the shutter mechanism. The shutter mechanism cuts the envelope at a certain length, and a double-structured molded product is completed.

Mixing in the extruder can be performed at a screw rotation speed of 300 to 800 rpm, preferably 350 to 700 rpm. The heating temperature may be at or above the temperature at which starch, added proteins, etc. gel, and the product temperature may be about 60 to 110°C, preferably 70 to 100°C, and more preferably 80 to 95°C. The discharge temperature may be 80 to 110°C, preferably 85 to 105°C. The outlet pressure may be 2 MPa to 10 MPa, preferably 4 MPaa to 8 MPa.

The combination ratio of the encapsulation and the composition for the outer shell can be 4:6 to 9:1 by weight, and is preferably 5:5 to 8:2. Combining them at such a weight ratio is preferable from the viewpoint of the elasticity of the resulting vitamin E-enriched farmed fish feed, the strength of the outer shell, etc.

The water activity may be adjusted taking into consideration the shelf life of the compound feed. This adjustment of water activity can be made by adjusting the composition of the encapsulation and/or the shell. For example, the water activity of the encapsulation can be lowered by adjusting the amount of water added. The water activity of the composition may be adjusted by adding water activity regulators such as salts (table salt, sodium malate, sodium lactate, etc.), sugars (sugar, lactose, maltose, sorbitol, etc.), sugar alcohols, amino acids, nucleic acid-related substances, organic acids, alcohols, propylene glucose, glycerin, starches, and proteins.

The amount of water added to the composition for the outer skin may be an amount that can be used with a filling machine or an extruder, and is preferably about 30 to 50% by weight. For example, the moisture content of the outer skin, which is created by wrapping the inclusions in a heated starch gel, can be about 25 to 50% by weight. The vitamin E-enriched farmed fish feed can be stored for a long time by storing it in a refrigerator or freezer. The feed can be further dried to a moisture content of 10 to 20% by weight. In this case, the shelf life can be further improved. By combining drying the outer skin with adding an additive to the composition for the outer skin to reduce the water activity, a feed that can be stored for a long time at room temperature can be produced. From the viewpoint of long-term storage, the outer skin of the compound feed preferably has a moisture content of 10 to 20% by weight and a water activity of 0.8 or less, particularly 0.75% or less, or 0.7% or less. In the present invention, the moisture content is measured using a value measured by a room temperature heating and drying method, and the water activity is measured using a water activity measuring device.

In the vitamin E enriched farmed fish feed, for example, various patterns can be considered for the blending of the composition for the outer skin containing starch. In the case of feed, the nutrients and calories required for the feed vary depending on the fish species or the growth stage of the fish. The more fish meal and fish oil are added, the more strictly the blending of the outer skin needs to be adjusted, but when the amount of fish meal and fish oil is less, there is considerable freedom in the blending of the outer skin. It is preferable that starch is contained at least 20 to 80% by weight of the total weight of the outer skin in dry matter terms. When the outer skin contains 25 to 50% by weight (dry matter terms), it is preferable to add 20 to 65% by weight of starch, 5 to 20% by weight of wheat flour, and 5 to 15% by weight of protein, oils and fats, thickeners, salts, etc. in dry matter terms. When the outer skin contains fish oil, it is preferable to add 1 to 5% by weight of fish oil, 1 to 2% by weight of phosphate, 1 to 5% by weight of protein, and 1 to 5% by weight of thickener.
When used as a secondary ingredient, wheat flour is preferably strong flour with a high gluten content, but weak flour may also be used. To improve the quality of the outer skin, additives used as quality improvers for starch foods can be added.

The method for producing a compound feed can include drying the double-layered compound feed obtained by cutting with the shutter mechanism, that is, a drying step.
There are no particular limitations on the drying means as long as it can dry the mixed feed. Drying conditions should be set so that the moisture content of the outer skin of the feed reaches the above-mentioned moisture content.

The drying conditions are preferably gentle, and can achieve a moisture content of 10 to 20% by weight in the skin. When gentle drying conditions are used, the moisture content of the skin decreases during the drying process, while the moisture content of the inclusions tends to be higher than the moisture content immediately after the cutting process due to the transfer of moisture from the skin. This makes it possible to obtain a vitamin E-enriched cultured fish feed with good physical properties that match the taste of cultured fish. The gentle drying conditions can be set appropriately based on the relative humidity, for example, at a temperature of 20°C to 45°C for 6 to 48 hours and within a relative humidity range of 20% to 50%. Any drying means can be used as long as it can achieve such gentle drying conditions, and examples include drying by placing the food on a mesh conveyor, mesh container, or sheet.

The method for raising farmed tuna fish according to one embodiment of the present invention includes feeding the tuna fish with the vitamin E-enriched farmed fish growth feed for at least 60 days. By continuing to raise the tuna fish with the vitamin E-enriched farmed fish growth feed for at least 60 days, vitamin E can be well accumulated in the bodies of the tuna fish being raised, and the accumulated vitamin E helps the fish to maintain a healthy state throughout the rearing period. Whether the farmed fish have been reared and managed can be confirmed by checking for characteristic components, such as vegetable oils, that are not contained in live feed and can remain in the fish bodies among the components of the vitamin E-enriched farmed fish growth feed that was fed to the tuna fish during the rearing period.

The rearing period using vitamin E-enriched farmed fish feed can be longer, for example, 3 months or more, 6 months or more, or 1 year or more. In this case, vitamin E can be stably accumulated, and vitamin E-enriched farmed fish with good physical characteristics can be reliably produced. Furthermore, by rearing the fish for a longer period using vitamin E-enriched farmed fish feed, good health can be maintained for a longer period.

The breeding conditions can be the same as those normally used for breeding tuna. For example, the water temperature during the breeding period can be 10°C to 32°C, and feeding can be once a day at full capacity during normal times and once every two days in winter.

During the rearing period, as long as the fish are fed vitamin E-enriched farmed fish feed for at least 60 consecutive days, there may be periods during which other feed is fed. Examples of other feed include live feed (horse mackerel, mackerel, etc.), moist pellets, etc.

Rearing can be started, for example, with individual fish weighing 200 g in total, or with individual fish weighing 500 g, 1 kg, or 10 kg in total. By starting rearing at such a time, it is possible to maintain the fish in a healthy state as they grow until the desired time, and rearing for such a period of time can provide the fish with vitamin E that meets their requirements.

The rearing period may be any time from the start of rearing to the final desired period, such as shipping or spawning. For example, the rearing period may be the period immediately prior to shipping. In this case, it is possible to supply vitamin E-enriched farmed fish with a stable accumulation of vitamin E, and edible parts thereof.

As long as the vitamin E-enriched farmed fish has the characteristics described in this specification, it may be produced by a method other than the breeding method described above, for example, by feeding the fish with food containing vitamin E.

<Method of manufacturing edible part>
The method for producing edible parts according to one embodiment of the present invention includes preparing farmed tuna fish that have been reared by the rearing method according to the embodiment described above, and harvesting edible parts from the prepared farmed tuna fish, and may include other steps as necessary.
In this method for producing edible parts, edible parts are harvested from farmed tuna fish raised by the rearing method in one embodiment described above, so that edible parts containing more vitamin E than conventional edible tuna parts can be efficiently obtained.

The farmed tuna fish may be individual fish or may be fish in the processed form described above. There are no particular limitations on the method for harvesting the edible parts, and a person skilled in the art can harvest them by a conventional method using tools normally used to cut out the desired edible parts from individual fish or parts thereof.

<Applications>
Vitamin E-enriched farmed fish and edible parts thereof are preferred as foods enriched in vitamin E, since they have a high concentration of vitamin E. Heated and unheated foods containing edible parts of vitamin E-enriched farmed fish include heated or unheated edible parts of tuna fish enriched in vitamin E, and are therefore preferred as foods enriched in vitamin E, and are presumed to be high-quality foods with less burnt meat due to the antioxidant power of vitamin E.
Because vitamin E-enriched farmed fish and their edible parts are enriched in vitamin E, they can be used as feed for livestock such as cows, pigs, and chickens, other farmed fish, and as animal feed such as pet food.

Since vitamin E-enriched farmed fish are raised for a certain period of time using vitamin E-enriched farmed fish feed that contains vitamin E, it is presumed that the antioxidant effects of vitamin E will enable the fish to maintain good health throughout the raising period, such as being resistant to stress and less susceptible to disease. As a result, vitamin E-enriched farmed fish are expected to be farmed fish that exhibit good growth potential.

The present invention will be described in detail below with reference to examples. However, the present invention is not limited to these examples.

[Example 1]
(1) Preparation of Vitamin E Enriched Cultured Fish Feed 35-40% by weight of fish meal, 17-23% by weight of starch (etherified tapioca starch: hydroxypropyl starch, Nippon Starch Chemical Co., Ltd., G-800), 7% by weight of wheat flour, 2% by weight of starch (acetate tapioca starch: Nippon Starch Chemical Co., Ltd., Z-300), 2% by weight of fish oil, 3% by weight of salt, 2.5% by weight of sugar, 1% by weight of gluten, and the remainder of water were mixed using an extruder under conditions of a screw rotation speed of 450 rpm, a discharge temperature of 90° C., and an outlet pressure of 50 bar (5 MPa) to prepare a composition for extruder skins.
59% by weight of fish meal, 36% by weight of fish oil, 1.965% by weight of hardened oil, 2% by weight of vitamins, 1% by weight of minerals, and 0.035% by weight of α-tocopherol were mixed using an extruder at 60°C and encapsulated. The vitamins used contained 3.03% by weight of vitamin E in terms of α-tocopherol.

In order to combine the outer shell composition and the encapsulation to produce vitamin E-enriched farmed fish feed, a co-rotating, fully intermeshing, twin-screw extruder (Buhler) with a double nozzle at the tip and an extrusion capacity of 1 t/h was used.
Both the composition for the outer shell and the inclusions were granulated from the double nozzle at the tip of the extruder, and a vitamin E-enriched cultured fish feed in which the inclusions were covered with the outer shells was obtained by a shutter device. The weight ratio of inclusions to inclusions was 65:35. The α-tocopherol content in the vitamin E-enriched cultured fish feed was 621 ppm.
The mixed feed immediately after molding was then placed on a transport conveyor and dried naturally for 24 hours in an environment of 30°C to 40°C and a relative humidity of 20% to 50%. This treatment resulted in good mixed feed with almost no cracks or other defects.
The moisture content of the outer skin of the obtained vitamin E-enriched farmed fish feed was 12-17%, and the water activity was less than 0.8. The moisture content of the inclusion was estimated to be about 4.7% immediately after molding. The moisture content was measured using a Drying Oven DX300 (manufactured by Yamato Scientific Co., Ltd.), and the water activity was measured using an Aqua Love CX-3 (manufactured by Milestone General Co., Ltd.).

(2) Rearing The prepared vitamin E enriched farmed fish feed was used to rear bluefin tuna.
About 3,000 tuna weighing about 16 kg and about 50 cm in length were housed in an elliptical fish cage with a diameter of 70 m, and rearing was started. The water temperature during the rearing period was 13°C to 29°C. The prepared vitamin E enriched farmed fish rearing feed was used as the feed, and the fish were fed satiety once a day in normal times and once every two days in winter. The feed intake was 30 to 50% by weight of the live feed throughout the test period. Rearing was started in March and continued for more than one year, and after a specified period, the α-tocopherol amount, weight, relative pyloric caeca weight, and obesity degree of each part were measured or calculated. The vitamin E amount in the liver was measured after 15 and 17 months, and the vitamin E amount in other tissues was measured in the fish body at 15 months of rearing. The results are shown in Tables 1 and 2.

The amount of α-tocopherol and the amount of total tocopherol were measured by HPLC after alkaline saponification treatment. The amount of total tocopherol means the total amount of α-tocopherol, β-tocopherol, γ-tocopherol and δ-tocopherol.
The test pieces for tuna were the central dorsal deep part (red meat), the central dorsal shallow part (medium fatty tuna), the central dorsal keel muscle, the dark muscle, the eyeball, the liver and the pyloric caeca.

Figure 1 shows the collection sites for the central dorsal deep part (Figure 1, part A), the central dorsal superficial part (Figure 1, part B), the central dorsal keel muscle (Figure 1, part C), and the dark muscle (Figure 1, part D). In Figure 1, E indicates the abdominal cavity.
The surface area of the dorsal muscle, called the "skin gishi," was taken, and the dorsal loin was cut perpendicularly from the rear end of the first dorsal fin toward the backbone. When the loin was separated into the head and tail sides, sample pieces of the central dorsal deep part (lean meat), central dorsal shallow part (chutoro), central dorsal keel muscle, and dark muscle were taken from the cut surface on the head side.

Regarding the eyeballs, the left and right eyeballs (vitreous bodies) and optic nerves were removed and finely chopped to prepare test specimens.
Regarding the liver, the liver that was removed as an internal organ at the time of harvest was entirely cut into small pieces to prepare test pieces.
Regarding the pyloric caeca, only the pyloric caeca was removed from the internal organs extracted during collection, and the entire body was finely chopped up to prepare the test pieces.

As shown in Table 1, it was confirmed that the total fish weight of the tuna raised on vitamin E-enriched farmed fish feed increased from about 16 kg at the start of the test to about 60 kg after about 15 months. The fish weight and fatness were almost the same as those of tuna raised using live feed. The relative pyloric caeca weight of wild tuna is generally about 1.4%, but the relative pyloric caeca weight of the tuna raised on vitamin E-enriched farmed fish feed was significantly higher than that of wild tuna. This indicates that tuna raised on vitamin E-enriched farmed fish feed is also advantageous for nutrient absorption.

On the other hand, as shown in Table 2, in tuna raised using vitamin E-enriched farmed fish feed, the vitamin E content exceeded 2 mg per 100 g in all tissues, including the flesh, eyeballs, liver, and pyloric caeca, indicating that vitamin E had accumulated at high concentrations. Thus, it was unexpected that raising tuna using vitamin E enriched in the feed resulted in high accumulation of 2 mg or more per 100 g in each tissue, and this was not observed with other fat-soluble vitamins, such as retinol.

As shown in Table 2, the amount of vitamin E accumulated in tuna raised using vitamin E-enriched farmed fish feed, i.e., vitamin E-enriched farmed fish, varied from tissue to tissue. In fish meat, vitamin E was found to accumulate in large amounts in the medium fatty tuna, dark muscle, and central ventral keel muscle, and in the eyeball, liver, and pyloric caeca, compared to fish meat. The tendency of vitamin E accumulation did not necessarily correlate with the amount of lipids. Thus, it was unexpected that the amount of vitamin E accumulated in each tissue in vitamin E-enriched farmed fish differed, and that the eyeball, liver, and pyloric caeca accumulated more than the muscle. Vitamin E has the effect of preventing the increase of lipid peroxides, improving metabolic abnormalities in the retina, and promoting blood circulation in peripheral blood vessels, so high accumulation of vitamin E in the eyeball reduces eye fatigue, improves feeding ability, and is expected to prevent collision deaths of tuna in a breeding environment.

The vitamin E content in muscle (medium fatty tuna) was 19.8 mg/100 g at 14 months after the start of rearing, but after switching to live feed for 30 days, it dropped to 2.2 mg/100 g, but did not fall below 2.0 mg/100 g. When live feed was given for only 30 days during the rearing period, no high accumulation of α-tocopherol was observed, indicating that rearing with vitamin E-enriched farmed fish feed for a certain period of time is necessary for the accumulation of vitamin E.
The lean meat and fatty meat (chutoro) used in the measurements were eaten as sashimi and were delicious.

These results suggest that the use of vitamin E-enriched farmed fish feed will enable growth comparable to that achieved with live feed, with higher relative pyloric caeca weight and greater nutrient absorption. Furthermore, this tuna has high concentrations of vitamin E accumulated in each tissue, and accumulation in the eyeball in particular has been confirmed, which is expected to result in high immune activity and good eyesight.
From such vitamin E-enriched farmed fish, edible parts such as fish meat, internal organs such as liver, and eyeballs, which have a high vitamin E content, can be harvested and provided as cooked or unheated products. The edible parts of vitamin E-enriched farmed fish have good preservability due to the action of vitamin E, and are of high economic value as a delicious food with high nutritional value.

[Example 2]
(1) Preparation of Vitamin E-Enriched Cultured Fish Feed 24% by weight of fish meal, 16% by weight of starch (etherified tapioca starch: hydroxypropyl starch, Nippon Starch Chemical Co., Ltd., G-800), 2% by weight of wheat flour, 2% by weight of starch (waxy corn starch: Nippon Starch Chemical Co., Ltd., Delica SE), 2% by weight of starch (tapioca acid cross-linked pregelatinized starch: Matsutani Chemical Co., Ltd., Pine Gold VE), 2% by weight of carboxymethyl cellulose, 3% by weight of protein (powdered soy protein: Fuji Oil Co., Ltd., New Fujipro SEH), 2% by weight of fish oil, 3% by weight of salt, 3% by weight of starch syrup, 2% by weight of gluten, 0.5% by weight of phosphate, and the remainder of the water were mixed under the same conditions as in Example 1 to prepare a composition for skin.
For the encapsulation, the following components were mixed under the same conditions as in Example 1 to obtain encapsulation 2-1 and encapsulation 2-2. The vitamins used contained 3.03% by weight of vitamin E calculated as α-tocopherol.

Connotation 2-1:
Fish meal 56.211% by weight, fish oil 38% by weight, vitamins 2.7% by weight, hardened oil 1% by weight, minerals 2% by weight, α-tocopherol 0.05% by weight, CoQ10 0.015% by weight, anhydrous calcium iodate 0.024% by weight.
Connotation 2-2:
Fish meal 56.25% by weight, fish oil 38% by weight, vitamins 2.7% by weight, hardened oil 1% by weight, minerals 2% by weight, α-tocopherol 0.05% by weight.

The above-mentioned composition for outer skin was combined with inclusion 2-1 or inclusion 2-2 under the same conditions as in Example 1 to obtain vitamin E-enriched farmed fish feed 2-1 or 2-2, in which the inclusion was surrounded by the outer skin. The weight ratio of inclusion to inclusion was 65:35. The α-tocopherol content in the vitamin E-enriched farmed fish feed was 830 ppm for vitamin E-enriched farmed fish feed 2-1 and 920 ppm for vitamin E-enriched farmed fish feed 2-2.

Thereafter, the mixed feed immediately after molding was placed on a transport conveyor and dried by natural drying for 24 hours under the same conditions as in Example 1, i.e., in an environment of 30°C to 40°C and a relative humidity of 20% to 50%. As a result of this treatment, a good mixed feed with almost no cracks or the like was obtained.
The moisture content of the outer skin of the obtained vitamin E-enriched farmed fish feed was 12-17%, and the water activity was less than 0.8. The moisture content of the inclusion was estimated to be about 4.7% immediately after molding. The moisture content was measured using a Drying Oven DX300 (manufactured by Yamato Scientific Co., Ltd.), and the water activity was measured using an Aqua Love CX-3 (manufactured by Milestone General Co., Ltd.).

(2) Rearing The prepared vitamin E enriched farmed fish feeds 2-1 and 2-2 were used to rear bluefin tuna.
About 200 tuna weighing about 15 kg and with a fork length of about 90 cm were housed in an elliptical fish cage with a diameter of 15 m, and rearing was started. The water temperature during the rearing period was 13°C to 29°C. The prepared vitamin E enriched farmed fish rearing feeds 2-1 and 2-2 were used as feed, and the tuna were fed satiety once a day in normal times and satiety once every two days in winter. Throughout the test period, the feed intake was 30 to 50% by weight of the live feed. Rearing began in May and continued for more than one year. After a predetermined period, the α-tocopherol content, weight, and fatness of the central dorsal ordinary muscle shallow part (medium fatty tuna) were measured or calculated. The α-tocopherol content was measured by the same method as in Example 1. The test pieces were collected and prepared by the same method as in Example 1.
The protein content in the superficial part of the central dorsal ordinary muscle (chutoro) was measured by the Kjeldahl method, and the lipid content was measured by the Soxhlet extraction method.
The results are shown in Tables 3 and 4.

As shown in Tables 3 and 4, the amount of vitamin E accumulated in the shallow dorsal ordinary muscle (medium fatty tuna) of other vitamin E-enriched farmed fish raised using vitamin E-enriched farmed fish growth feeds 2-1 and 2-2 exceeded 2 mg per 100 g for both 6 and 8 months of growth.
In this example, feeding was restricted (once every 3-4 days) due to the occurrence of typhoons and red tides during the first 6 months of rearing, and low water temperatures of 18°C or less during the period from the 6th to 8th months, but tuna with high accumulation of vitamin E were obtained. The survival rate of this tuna was over 95%.

Claims (3)

A method for raising farmed fish enriched in vitamin E, comprising continuously feeding farmed tuna fish a compound feed containing 500 ppm or more of vitamin E based on the total feed for at least 60 days, the method comprising: feeding the farmed tuna fish a compound feed containing 500 ppm or more of vitamin E based on the total feed; and producing farmed fish enriched in vitamin E, the fish containing at least one selected from the group consisting of muscle containing 30 mg or more of vitamin E per 100 g, liver containing 30 mg or more of vitamin E per 100 g, and eyeballs containing 27.1 mg or more of vitamin E per 100 g. The method for raising vitamin E-enriched farmed fish according to claim 1, wherein the compound feed comprises an inclusion containing fish meal and fats and oils, and an outer shell that encases the inclusions and is at least one heat-induced gel selected from the group consisting of proteins and polysaccharides. The method for raising vitamin E-enriched farmed fish according to claim 2, wherein the vitamin E content in the inclusions is 500 ppm or more relative to the total feed.