WO2015030008A1

WO2015030008A1 - Eel feed, method for raising eel fry, method for producing cultivated eels, and method for increasing amino acids in eel flesh

Info

Publication number: WO2015030008A1
Application number: PCT/JP2014/072326
Authority: WO
Inventors: 美貴日野; 浩一井口; 慶一井上
Original assignee: 株式会社西日本冷食
Priority date: 2013-08-29
Filing date: 2014-08-26
Publication date: 2015-03-05
Also published as: TW201513791A; JP2015043752A; JP5485457B1

Abstract

　Provided are an eel feed, a method for raising eel fry, and a method for producing cultivated eels, capable of producing cultivated eels having an aroma, flavor, and eating feel equal to that of natural eels. An eel feed obtained by adding to a mixed feed a raw material derived from mantis shrimp, in which only the tail portion is removed from the mantis shrimp and the head portion (head shell and content) and body portion (shell and flesh) are used as raw ingredients. The eel feed is appropriate not only as a feed for adult eel but also for eel fry. By cultivating eels using the eel feed, cultivated eels can be produced that have an aroma, flavor, and eating feel equal to that of natural eels. By giving the eel feed to cultivated eels, the amount of various amino acids in the flesh of the eels is increased.

Description

Eel feed, eel growth method, cultured eel production method, and amino acid increase method of eel meat

(Priority information)
This application claims priority to Japanese Patent Application No. 2013-178275 filed on Aug. 29, 2013. The contents of the Japanese application are incorporated herein. The Japanese patent application was set and registered as Japanese Patent No. 5485457 on February 28, 2014.

The present invention relates to an eel feed that can safely produce eels having an odor, taste, and texture comparable to natural eels, a method for growing eel fry using the feed, a method for producing cultured eels, and eel body The present invention relates to a method for increasing amino acids in meat.

Eel is a fish belonging to the eel family Angullidae and is cultivated in neighboring countries in addition to Japan. In general, farmed eels are produced by placing naturally collected white eels and larvae such as crocodile larvae in cultured ponds and raising them to adult eels. Cultured eels have a peculiar smell of farmed fish, and the content of amino acids, which are umami components, is low compared to natural eels, and the texture is often poor. Moreover, it is known that the eel cultivated by the normal compound feed lacks the useful amino acid amount compared with the natural eel. Therefore, there is a need for a method for producing cultured eels that have a smell, taste and texture close to those of natural eels.

In eel aquaculture, a mixed feed based on fish meal obtained by drying blue fish such as sardines, mackerel, herring and horse mackerel is generally used as eel feed, but is included in blue fish such as sardines and horse mackerel. Unsaturated fatty acids are oxidized and converted into peroxy fatty acids by applying high heat in the process of formulating feeds, which is one of the causes of the unique smell of farmed fish.
Eel farming begins with the rearing of the larvae, the white eel, and then the crocodile on which the glass eel grew. In recent years, eel fry such as natural glass eel and crocodile has been drastically reduced, and it is required to improve productivity during aquaculture. Therefore, there is a demand for a eel feed that has good palatability with eel fry such as white eel and crocodile and is safe. As feeds for eels, for example, the feeds of Patent Document 1 and Patent Document 2 have been reported. However, the above-described conventional feeds for eels do not necessarily have good palatability for eel fry, and diseases occur in eel fry. There was a case. Furthermore, the cultured eel produced has a characteristic odor of cultured fish, and its nutritional value is less than that of the natural eel.

In the nonpatent literature 1, the present inventors have reported the example which gave the compound feed which added the giant clam surimi to the adult eel fish. However, the effect of improving the taste of eel was not always satisfactory.
In addition, in the Non-Patent Document 2, the present inventors have provided an eel feed containing raw materials derived from unused parts such as the shells of shells, heads, tails, and flakes, and tried to improve the taste of eels. An example is reported. However, it has been found that when this eel feed is given, eels are weakened, growth is suppressed, and the rate of sudden death increases. For this reason, the eel feed is not necessarily suitable as a commercial aquaculture feed.

Japanese Patent Laid-Open No. 11-253111 JP-A-2005-13116

Thus, there remains room for improvement in conventional eel feed and eel farming methods. A feed that has good palatability by eel fry such as white eel and crocodile, is easy to handle, and does not inhibit growth or cause disease is desired.
Under such circumstances, an object of the present invention is to enable an eel having an odor, taste, and texture comparable to those of a natural eel to grow safely and soundly without causing growth inhibition or disease. It is to provide a feed for use, a method for growing eel fry and a method for producing cultured eel. Another object of the present invention is to provide a method for increasing amino acids of eel meat that increases the umami component of cultured eel.

As a result of intensive research to solve the above-mentioned problems, the present inventor has a hard and sharp portion in the tail of the giant clam, which damages the internal organs of the eel (especially the esophagus), which weakens the eel and suppresses growth. And found that the rate of sudden death increases, leading to the present invention.

The present invention relates to the following inventions.
<1> For eels made by adding raw materials derived from giant clams from the head (head crust and contents) and trunk (shells and meat), with the tails of the giant clams removed. feed.
<2> When the sum of the dry weights of the raw materials for the giant clam and each of the blended feeds is 100% by weight, the raw material for the giant clam is contained in an amount of 5% by weight to 45% by weight. Eel feed.
<3> The eel feed according to <1> or <2>, wherein the blended feed is fish meal as a main component.
<4> The eel feed according to any one of <1> to <3>, further containing lactic acid bacteria.
<5> A method for growing eel fry, wherein the eel fry is fed with the eel feed according to any one of <1> to <4>.
<6> The method for growing eel fry according to <5>, wherein the eel fry is crocodile.
<7> A method for producing a cultured eel including a step of growing eel fry by the growth method according to <5> or <6>.
<8> A method for producing a cultured eel that feeds the eel feed according to any one of <1> to <4> to an adult eel.
<9> A method for increasing amino acid content of eel meat, wherein the eel feed is fed to the eel feed according to any one of <1> to <4>, and the amino acids contained in the eel meat content are increased.
<10> The amino acid increasing method for eel meat according to <9>, wherein the increasing amino acid is one or more amino acids selected from glycine, alanine, proline and arginine.

According to the present invention, there is provided an eel feed that has high palatability for eel fry and adult eels, and can grow eels well. By feeding and cultivating the eel feed, a cultured eel having an odor, taste and texture comparable to natural eels can be obtained. Moreover, the amount of amino acids of eel meat can be increased by feeding the eel feed.

It is a figure which shows the analysis result about the threonine contained in 100g of cultured eel flesh. It is a figure which shows the analysis result about the methionine contained in 100g of cultured eel flesh. It is a figure which shows the analysis result about isoleucine contained in 100g of cultured eel flesh. It is a figure which shows the analysis result about leucine contained in 100g of cultured eel flesh. It is a figure which shows the analysis result about the tyrosine contained in 100g of cultured eel flesh. It is a figure which shows the analysis result about the phenylalanine contained in 100g of cultured eel flesh.

Hereinafter, the present invention will be described in detail with reference to examples and the like, but the present invention is not limited to the following examples and the like, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[1] Eel feed The eel feed of the present invention is a raw material for eel that uses only the head (head crust and contents) and trunk (shell and meat) from which the caudal tail is removed. Is added to the mixed feed.
In addition, in this specification, "eel" is a concept including the eel fry called Shirasu eel and Croco and the adult eel which the eel fry grew. Details of eel fry and adult eel will be described later.

(Shrimp-derived materials)
In the present specification, the “raw material derived from shrimp” is a raw material derived from shrimp, and the shell, head contents, meat, tail, etc. of shrimp are kept raw or frozen, heated and dried. It is a concept that includes things. These are usually used after being chopped, crushed, pressed or grated. Specifically, the raw materials for giant clams are crushed into whole minced crusts, including shells, heads, and meat, and separated into minced shells, crustaceans, heads, and meats. , Pulverized and mixed necessary parts, and the like.

Mantis shrimp (Oratosquilla oratoria), giant shrimp (Anchisquilla fasciata), European shrimp (Squilla mantis), shrimps (Harpiosquilla harpax), shrimp clover (Bathysquilla crassispinosa) Eel octopus (Upogebia major), Okinawa octopus family Thalassina.
Among these, a giant clam (Oratosquilla oratoria) and an octopus (Upogebia major) are preferable.

One of the features of the eel feed of the present invention is that it includes the heads (head crust and contents) of giant clams. The heads of giant clams are known to contain various enzymes, and because they contain shells, some fish are not suitable for aquaculture feed. In the case of eels, these enzymes, shells It becomes an excellent feed by including the part.

One of the characteristics of the eel feed of the present invention is that it includes the trunk part (shell and meat) of the giant clam.
As will be described later in Examples, the crustacean shell has a higher amount of carbohydrate per unit weight and energy compared to the contents of the head and meat. Furthermore, the crustacean shell is usually a residue, which is excellent in terms of effective use of waste. And by including the flesh of the giant clam, the taste and texture are further improved as compared to the raw material derived from the giant clam consisting of the head and shell of the giant clam.

And in the feed for eels of the present invention, raw materials (hereinafter referred to as the shell and meat) consisting of the head (head crust and contents) and the trunk (shell and meat), with the tail of the crustacean removed only, It may be referred to as “headed mantis”). That is, the eel feed of the present invention has the greatest feature in that it does not include the tail of the giant clam.
There is a hard and sharp part in the tail of the giant clam, and when eaten by an eel, the internal organs (especially the esophagus) of the eel are damaged. As a result, there is a problem in that the proportion of eels is weakened and growth is suppressed, or the rate of sudden death increases. Suppression of growth and sudden death from the tail of the giant clam, especially eel fry (especially crocodile), which is weaker in resistance and resilience compared to adult eels, and fully grown to a weight of about 200g after growing from eel fry This is especially a problem for adult eels that are not.
The feed for eels of the present invention uses headed oysters that do not include the tails of mantis, so growth suppression and sudden death caused by feeding of the tail of the mantis does not occur, and the head of the mantis ( The taste and texture of eel derived from the head shell and contents) and the trunk (shell and meat) are further improved.

The ratio of the head (head crust and contents) and trunk (shell and flesh) in the raw materials of giant clams is within the range where the odor unique to cultured fish can be sufficiently suppressed in consideration of the type of eel and the growth condition. As appropriate.

(Mixed feed)
The blended feed used as the raw material for the eel feed of the present invention is a mixture of various raw materials in appropriate proportions so as to sufficiently provide the nutrients necessary for eel growth. Specifically, it can be used as a well-known feed for cultured fish in which fish meal and other components are mixed. Examples of other components include starch, calcium phosphate, salt, yeast, and herbal extract.

Examples of the raw material for fish meal include powder obtained by processing sardines, mackerel, herring, horse mackerel, etc., but other fish may be used. The seafood used as the raw material for the fish meal may be used alone or in combination of two or more, and is appropriately selected in consideration of the type of eel, growth state, cost, and the like.

In the eel feed of the present invention, it is preferable that the mixed feed is mainly composed of fish meal. Here, “main component” means that at least 50% by weight or more of the mixed feed is fish meal. If the proportion of fish meal in the blended feed is too small, the nutritional value of the feed may be insufficient and the growth of eels may deteriorate.

(Other ingredients)
The eel feed of the present invention may contain components other than the raw materials derived from the giant clam and the mixed feed. Suitable other ingredients include shellfish such as swordfish, clams and clams. Since the above-mentioned raw materials derived from giant clams are included, the odor peculiar to cultured fish is suppressed even when a fish meal-based mixed feed is used, but a cultured eel with less odor can be obtained by adding shellfish.

In addition, the eel feed of the present invention includes, as other ingredients, dried vegetables (particularly preferably powdered), lactic acid bacteria, active live bacteria such as butyric acid bacteria and saccharifying bacteria, and protein / lipolysis Digestive enzymes such as enzymes may be added.
The eel feed of the present invention preferably contains lactic acid bacteria. Although the detailed mechanism is not clear, when the eel feed of the present invention contains lactic acid bacteria, it prevents the growth of bad bacteria, infectious bacteria, etc. Can suppress various diseases. By adding these, eel farming with higher growth efficiency and yield can be achieved.

The eel feed of the present invention can be produced by mixing a mixed feed (and other components as required) with the giant clam-derived raw material. Moreover, you may add water, oil, etc. as needed so that it may be easy to make a bait.
The proportion of raw material derived from giant clam in the eel feed is determined within a range that does not cause growth inhibition or disease without deteriorating the smell, taste and texture of cultured eel produced. It is appropriately selected in consideration of the growth state (fry or parent fish), but when the total dry weight of each of the raw materials for the giant clam and the mixed feed is 100% by weight, the raw material for the giant clam is 5% by weight. The content is preferably 45% by weight or less, more preferably 15% by weight or more and 45% by weight or less, and still more preferably 20% by weight or more and 40% by weight or less. If less than 5% by weight of raw material derived from the giant shrimp, there is a risk that the effect of improving the growth of eels by the raw material derived from shrimp will not be observed. If it exceeds 45% by weight, the viscosity of the feed will be too low and it will be difficult to consolidate. The feed may disperse and the water may become dirty.

[2] Method for producing cultured eel The method for producing the cultured eel of the present invention will be described below.
The method for producing a cultured eel of the present invention is characterized in that the cultured eel is fed with the eel feed of the present invention described above. As described above, by feeding and cultivating the eel feed of the present invention containing the raw material from the giant clam, the odor peculiar to the cultured fish is reduced from the cultured eel, and the taste and texture are also improved.
The method for producing cultured eels of the present invention includes “a method for growing eel fry” for eel fry and “a method for producing a cultured eel for eel adult fish”. It shall be referred to as “aquaculture eel production method”.

As eels to be cultured, Japanese eels (Japonica eels, Anguilla japonica) and foreign eels (non-Japonica eels) are targeted, but Japanese eels are preferred. The production method of the cultured eel of the present invention is for eel fry to adult eel. The eel larvae to be cultured may be either artificially hatched or natural, but natural glass eel or crocodile is usually used.
The eel fry referred to in the present invention is a concept including from white eels having a body weight of less than 0.5 g and a body length of less than 6 cm to a crocodile having a body weight of 0.5 g to 100 g (body length of 6 cm or more). The eel hatching larvae that contain the crocodile and grow from the egg to the glass eel are excluded.
Moreover, an eel adult fish means the eel which grew from the said eel fry. Adult eels are usually shipped as eel parent fish grown to about 200-330g.

The growth method of the eel fry of the present invention is characterized by feeding the eel fry with the above-described eel feed of the present invention. That is, it is a method of feeding the eel feed of the present invention during the period of eel fry with high mortality (white eel, crocodile).
The eel feed of the present invention has good palatability for eel fry as well as grown eel adult fish. And since it does not include the tail of the giant clam that causes growth inhibition of eel fry and sudden death, according to the method for growing eel fry of the present invention in which the feed is fed to the eel fry, The probability of dying is reduced, and it is possible to grow up to eel adult fish with good yield.
Then, by feeding the adult eel with the eel feed of the present invention and culturing it, a cultured eel having an odor, taste and texture comparable to those of a natural eel can be obtained.

Eel fry to be grown is preferably crocodile. Suppression of growth of eel fry and improvement in mortality are likely to occur at the time of croko (weight 0.5g to 100g, body length 6cm or more) from eel fry to eel adult fish. Therefore, when the eel feed of the present invention is fed and grown at least at the time of the crocodile in the eel to be cultured, growth inhibition and mortality are reduced, and it is possible to grow up to adult eels.

As described above, in the method for producing a cultured eel of the present invention, it is preferable to give the eel feed of the present invention to the entire breeding period until the eel fry becomes a eel parent fish. That is, it is preferable to feed the eel feed of the present invention to a grown eel that includes the step of growing eel fry by the above method.
On the other hand, the odor, taste, and texture of cultured eels are particularly affected by the adult eel season, so even if the eel fry is not supplied with the eel feed of the present invention, the eels that have grown to adult eels will be affected. The cultured eel may be produced by feeding the eel feed of the invention. In particular, it may be given only for a period from 60 days before shipment (preferably 90 days before) to shipment, which particularly affects the smell, taste and texture of cultured eel.

Moreover, although a detailed reason is not clear at this stage, the amino acid of the eel meat can be increased by the method of feeding the eel with the eel feed of the present invention.
Examples of the amino acid to be increased include methionine, isoleucine, leucine, tyrosine, phenylalanine, glycine, alanine, proline, arginine and the like.
Among amino acids in eel meat, increases in glycine, alanine, proline and arginine, which are indicators of umami components, are observed, and glycine, alanine and proline are particularly increased. In order to increase the amino acid content of eel meat, it is preferable to give it at least 60 days before loading (preferably 90 days before) to shipping.

The cultured eel produced by the production method of the present invention increases the amount of amino acids related to the umami component of eel meat, and has an odor, taste and texture comparable to natural eels.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

(1) Manufacture of eel feed “eel feed of Example 1 (20% added feed)”
The eel feed of Example 1 was produced as follows.
Frozen mantis was thawed and used as a mantis-derived material. The frozen clam includes a head (crust portion and contents) and a torso (crust portion and flesh) except for the tail of the clam (hereinafter referred to as “headed clam”). As a mixed feed, a mixed feed comprising fish meal (74% by weight), pregelatinized starch (23% by weight), and the balance (3% by weight) consisting of calcium phosphate, salt, feed yeast and licorice extract was used.
First, 90 g of water was added to 80 g of frozen giant clam (dry weight 20 g), and mixed with a mixer to obtain giant mince. The total amount of the obtained minced minced meat, 80 g (dry weight) of the mixed feed and 30 g of water were sufficiently kneaded in a predetermined container until uniform, and the eel feed of Example 1 was obtained. In addition, the feed for eels of Example 1 may be hereinafter referred to as “20% added feed” on the basis of the dry weight of the giant clam-derived material.

"Eel feed of Example 2 (40% added feed)"
The raw material and compound feed which are the same as the feed for eels of Example 1 were used as a raw material. First, 160 g of water was added to 160 g (dry weight 40 g) of the frozen giant clam and mixed with a mixer to obtain a giant mince. The total amount of the obtained citrus mince and 60 g (dry weight) of the mixed feed were sufficiently kneaded in a predetermined container until uniform, and the eel feed of Example 2 was obtained. In addition, the feed for eels of Example 2 may be hereinafter referred to as “40% added feed” on the basis of the dry weight of the giant clam-derived material.

"Eel feed for Example 3 (50% added feed)"
The raw material and compound feed which are the same as the feed for eels of Example 1 were used as a raw material. First, 50 g of water was added to 200 g of frozen giant clam (dry weight 50 g), and the mixture was mixed with a mixer to obtain giant clam mince. The total amount of the obtained citrus mince and 50 g (dry weight) of the mixed feed were sufficiently kneaded in a predetermined container until uniform, and the eel feed of Example 3 was obtained. In addition, the feed for eels of Example 3 may be hereinafter referred to as “50% added feed” on a dry weight basis of the giant clam-derived material.

(2) Evaluation (2-1) Composition of raw materials derived from giant clams, blended feed, and feed for eels of the examples Table 1 shows the head contents from headed mantis (frozen mantis head and trunk) and headed mantis. Ingredient composition of “headed crustacean crust only” from which items and meat are removed. In addition, the numerical value in a table | surface is the weight (g) and energy (kcal) with respect to 100g of samples, respectively.

Tables 2 and 3 show the composition of the mixed feed and the eel feeds of Examples 1 and 2. Table 2 shows values including moisture, and Table 3 shows values on a dry weight basis.

(2-2) Shape retention of eel feed The eel feed of Examples 1 to 3 had an appropriate viscosity when kneaded, and showed sufficient moldability as an eel feed. Then, when these eel feeds were put in water and observed how the feeds were scattered, the eel feeds of Examples 1 and 2 were maintained in moldability without splitting even after 30 minutes or more. On the other hand, the eel feed of Example 3 was put into water and started to split after a while.
Accordingly, an intermediate value of 45% by weight or less (sum of dry weights of the raw materials of the giant clam-derived material and the mixed feed) of Examples 2 and 3 or less was determined as the upper limit value at which the eel feed would not break up in water.

(2-3) Aquaculture test “Aquaculture test 1”
An eel aquaculture test was conducted using Example 1 (20% added feed) and Example 2 (40% added feed), which are more excellent in formability in water, as eel feed.
In the aquaculture test, six 5 ton water tanks (water volume of about 2 tons) were used as test zones. As an eel to be evaluated, 720 cultured eels (about 200 g in size) produced in Kagoshima Prefecture were used. Each of these eels was placed in a six-sided water tank (A-1 to A-6), 120 individuals, and each was fed with a mixed feed that did not contain the raw material of the giant clam, until the feeding was stabilized. Subsequently, the control section (A-1, A-2) fed with the mixed feed (without the raw materials derived from the giant clam), and the section (A-3) fed with the eel feed of Example 1 (20% added feed) , A-4), the eel growth state was evaluated for the sections (A-5, A-6) to which the eel feed of Example 2 (40% added feed) was fed. Eels were fed once a day, and the feed amount was calculated with 1.6% by weight of eel body weight as a guide. In addition, the amount of feeding was varied in the range of 100 to 500 g depending on the situation such as the growth state of eels.

About the eel farmed by the method mentioned above, investigation of the growth condition and component analysis were performed.
The growth status was examined by measuring the total length (mm), preanal length (mm), and body weight (g) of the eel to be measured.
Evaluation was performed on 30 individuals arbitrarily selected the day after the delivered eels were placed in a 6-sided aquarium, and grown on the A-1, A-4, and A-6 sections 60 days after the start of the cultivation. The above-mentioned evaluation was performed for each 20 eels, and the growth status was compared.
In the component analysis, five eels each grown in the sections A-1, A-4, and A-6 were taken out, and component analysis was performed on the components of the meat part of the eel from which the skin was removed. In addition, the component analysis was carried out at the Fukuoka Prefectural Industrial Technology Center Biofood Research Laboratory.

Table 4 shows the eel growth status 60 days after the start of breeding.
As shown in Table 4, the eels in the sections (A-4, A-6) fed with the eel feed of Examples 1 and 2 had all the length (increased), preanal length, and body weight controlled. It was confirmed that it was larger than the section (A-1). As shown in Tables 2 and 3, since the eel feed of Examples 1 and 2 has a smaller amount of energy than the control mixed feed, the results of the growth evaluation are the results of the eel feed of Examples 1 and 2. It means that the growth of eel is promoted by the raw material derived from the giant clam.
In addition, it was confirmed that the eel growth was particularly good in the eel feed (40% added feed) of Example 2.

FIGS. 1 to 6 show the analysis results of amino acids (threonine, methionine, isoleucine, leucine, tyrosine and phenylalanine) contained in 100 g of eel meat 60 days after the start of feeding. 0% of the horizontal axis is eel (control group) cultivated only with mixed feed, 20% is eel cultivated using the eel feed of Example 1 (20% added feed), and 40% is implemented It is an eel farmed using the eel feed of Example 2 (40% added feed).

As shown in FIG. 1, threonine is 106% in eels cultured in the eel feed (added 20% feed) of Example 1 and eels cultured in the control group (mixed feed only), It was 151% among eels cultivated using eel feed (40% added feed).
As shown in FIG. 2, methionine was 111% in the eel cultured in the eel feed (added 20% feed) of Example 1 with respect to eel cultured in the control group (mixed feed only). It was 111% for eels cultured using eel feed (40% added feed).

As shown in FIG. 3, isoleucine was 111% in the eels cultured in the eel feed of Example 1 (20% added feed) versus eels cultured in the control group (mixed feed only). It was 107% for eels cultured using eel feed (40% added feed). As shown in FIG. 4, leucine was 111% in eels cultured in the eel feed (20% added feed) of Example 1 versus eels cultured in the control group (mixed feed only). It was 107% for eels cultured using eel feed (40% added feed).

As shown in FIG. 5, tyrosine is 148% in the eels cultured in the eel feed (20% added feed) of Example 1 versus eels cultivated in the control group (mixed feed only). It was 129% for eels cultured using eel feed (40% added feed).
As shown in FIG. 6, phenylalanine is 150% in eels cultured in the eel feed (20% added feed) of Example 1 versus eels cultured in the control group (mixed feed only). It was 147% among eels cultivated using eel feed (40% added feed).

Table 5 summarizes the results of amino acid evaluation of cultured eel meat in aquaculture test 1.

"Aquaculture test 2"
Using the eel feed of Example 2 (40% added feed), an eel aquaculture test was conducted, the amino acid component, which is an umami component contained in the eel meat, was evaluated, Compared to natural eel.
The aquaculture test used two 5-ton water tanks (approximately 2 tons of water) as test zones. As an eel to be evaluated, 200 cultured eels (about 200 g in size) produced in Kagoshima Prefecture were used. Each of these eels was placed in two aquariums (B-1, B-2), and each was fed with a mixed feed that did not contain a raw material from the giant shrimp, until the feeding was stabilized.
Subsequently, for the control section (B-1) fed with the mixed feed (without the raw materials derived from the giant clam), the section (B-2) fed with the eel feed of Example 2 (40% added feed), the eel The growth state of the rice was evaluated. Eels were fed once a day, and the feed amount was calculated with 1.6% by weight of eel body weight as a guide. In addition, the amount of feeding was varied in the range of 100 to 500 g depending on the situation such as the growth state of eels.
By the above method, amino acids (glycine, alanine, proline, arginine, and histidine) contained in 100 g of eel meat 90 days after the start of feeding were analyzed. Moreover, the same amino acid analysis was performed also about the natural eel (from Saga Prefecture) as a reference example. In addition, the evaluated amino acid corresponds to an amino acid that serves as an index for the umami taste of eel.

Table 6 summarizes the results of amino acid evaluation of cultured eel meat in the aquaculture test 2. In addition, a numerical value is the amount of amino acids (mg) contained in 100 g of eel meat.
As shown in Table 6, it can be seen that the eels cultured using the eel feed of Example 2 (40% added feed) have an amino acid content comparable to that of the natural eel.
The amino acid content (relative value) of eel cultured using the eel feed (40% added feed) of Example 2 when the amino acid content of the eel cultured in the control group (mixed feed only) is 100% is glycine. They were 178%, alanine 123%, proline 144%, and arginine 114%.

Eel and natural eel cultivated in aquaculture test 2 were cooked in white grill and evaluated for odor, taste and texture. Eel cultivated in the control group (mixed feed only) had a unique smell of cultured fish, The texture was inferior to natural eels. On the other hand, the eels cultured using the eel feed of Example 2 (40% added feed) did not feel the unique smell of cultured fish, and the taste and texture were inferior compared to natural eels.
From this result, it was confirmed that by giving the eel feed of the present invention from about 90 days before shipment, a cultured eel comparable to the natural eel can be produced.

(2-5) Feeding to eel fry and observation of growth Using the eel feed of Example 2, the growth of the eel fry was observed.
As eel fry, 4500 cultured crocodiles (weight approximately 25 to 50 g) were used. When 4500 eel fry reared in a 25-ton aquarium were bred by feeding eel feed once a day, 1.6 to 2.0% by weight of eel feed, 120 It was confirmed that the plant grew smoothly without any illness every day.

(2-6) Presence and absence of eel tails in eel feed and eel growth status Using the following eel feed, compare the growth status of eel feed with and without the tail of the octopus did.
(1) Feed for eel Feed for eel 1 (without tail): Mantis with the tail removed (headed mantis): 20% by weight
Formula feed: 80% by weight

Eel feed 2 (with tail): Mantis without removing tail: 20% by weight
Formula feed: 80% by weight

Eel feed 3 (control): Formula feed: 100% by weight

The eel feed 1 corresponds to the above-mentioned “eel feed of Example 1”, and the production method thereof is the same as that of Example 1. The mixed feed is the same as the mixed feed described in Example 1 above.

(2) Growth method Test area: 5 ton water tank: 3 eels to be evaluated: eels from Kagoshima prefecture (approx. 200g size)
Feeding amount: Calculated using 1.6% by weight of eel as a guide Breeding period: About 6 months About 200 eels to be evaluated are placed in each of the three aquariums, and 1 to 3 eel feeds are placed under the above conditions. Feeding once a day and growing eels. In the aquarium to which the eel feeds 1 and 2 were fed, the eel feed 3 was fed and acclimatized until the prey was stabilized (approximately several days) at the beginning of the culture.
An eel was arbitrarily taken out from each tank at a frequency of once a day, and the growth state of the eel in each tank was observed.

(Test results)
At the beginning of the test, no difference was observed with eel feeds 1 to 3, but from the first month of the test, compared to eel feed 3, eels 1 and 2 containing eel were provided. It was observed that the growth of
After that, the eels in the aquarium fed with eel feed (without tail) grew steadily, but the eels in the aquarium fed with eel feed 2 (with tail) died from about two months after the start of the test. Increased, and prey was also clearly worse.
When the dead eel was dissected in the water tank to which the feed 2 for eels was given, it was confirmed that water accumulated in the body and a thin but hard and sharp tail part was caught on the esophagus.

(2-7) Effects of lactic acid bacteria in eel feed Comparison of eel meat odor, taste, and texture with and without lactic acid bacteria in eel feed using the following eel feed did.
(1) Eel feed Eel feed A (without lactic acid bacteria): headed clam: 20% by weight
Formula feed: 80% by weight

Eel feed B (without lactic acid bacteria): Headed clam: 20% by weight
Formula feed: 80% by weight

Eel feed C (control): Formula feed: 100% by weight

The eel feed A corresponds to the above-mentioned “eel feed of Example 1”, and the production method thereof is the same as that of Example 1. The mixed feed is the same as the mixed feed described in Example 1 above.

The eel feed B was produced as follows. First, 90 g of water was added to 80 g of frozen headed oysters (dry weight: about 20 g) as in Example 1, and mixed with a mixer to obtain a minced meat. The total amount of the obtained minced minced meat, 70 g (dry weight) of the mixed feed and 30 g of water are sufficiently kneaded in a predetermined container until uniform, and further 0.1 g of dried vegetables, water-soluble tourase (registered trademark) containing lactic acid bacteria, etc. Eel feed B was obtained by adding and kneading 0.20 g of Toa Pharmaceutical Co., Ltd. and 0.05 g of vegetable oil.

(2) Growth method Test area: 5 ton water tank: 3 eels to be evaluated: eels from Kagoshima prefecture (approx. 200g size)
Feeding amount: Calculated using 1.6% by weight of eel body weight as a guide Breeding period: About 6 months About 200 eels to be evaluated are placed in each of the three aquariums, and eel feed A, B, and C are as described above. And fed once a day to grow eels. In the aquarium fed with eel feeds A and B, eel feed C was fed and acclimatized until the prey was stable (several days) at the beginning of the culture.

(Test results)
Eel feed A, B, and C were given, and fully grown cultured eels were cooked on a white grill and evaluated for odor, taste, and texture.
Eels cultivated with eel feed C (control group) smelled peculiar to farmed fish, and the taste and texture were inferior to natural eels.
On the other hand, eels cultivated with eel feed A and B did not feel the unique smell of farmed fish, and both taste and texture were good. In particular, the eel fed with the eel feed B containing lactic acid bacteria was better than the eel feed A in both taste, texture and smell.

The eel feed and the cultured eel production method of the present invention can produce cultured eels that have an odor, taste and texture comparable to natural eels. Furthermore, since residues such as heads and shells can be effectively used in addition to the clam meat that is usually discarded, it can contribute to the reduction of industrial waste.

Claims

It is characterized by adding to the compound feed the raw materials derived from the giant clam with the head (head crust and contents) and the trunk (shell and meat) as raw materials, with the tail of the giant clam removed. Eel feed.
The eel-derived material for eels according to claim 1, wherein the material of the giant clam-derived material is contained in an amount of 5 wt% or more and 45 wt% or less when the total dry weight of the crab-derived material and the blended feed is 100 wt%. feed.
The eel feed according to claim 1 or 2, wherein the blended feed is mainly composed of fish meal.
The eel feed according to any one of claims 1 to 3, further comprising lactic acid bacteria.
A method for growing eel fry, wherein the eel fry is fed with the eel feed according to any one of claims 1 to 4.
The method of growing eel fry according to claim 5, wherein the eel fry is crocodile.
A method for producing a cultured eel comprising a step of growing eel fry by the growth method according to claim 5 or 6.
A method for producing a cultured eel characterized by feeding adult eels with the eel feed according to any one of claims 1 to 4.
5. A method for increasing amino acids in eel meat, characterized in that the eel feed according to any one of claims 1 to 4 is fed to the eel and the amino acids contained in the eel meat are increased.
The method for increasing amino acids of eel meat according to claim 9, wherein the increasing amino acid is one or more amino acids selected from glycine, alanine, proline and arginine.