JP2593765B2 - Feed for cultured fish and shellfish - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed for cultured fish and shellfish, and more particularly to a feed for cultured fish and shellfish which improves coloration.

[0002]

2. Description of the Related Art Astaxanthin is a type of carotenoid red pigment, and is known as Phaffia rhodozyma.
ia rhodozyma), a yeast belonging to Haematococcus (Haema
tococcus), Chlamydomonas and the like, starfish, crustaceans such as shrimp, krill and crab, and fish.

[0003] However, not all of them biosynthesize astaxanthin, and it is said that some of them (marine red fish such as red sea bream, salmon and trout) do not have astaxanthin biosynthesis ability.

[0004] Therefore, when farming such fish,
A low astaxanthin content in the feed will result in a different appearance than the natural fish. For example, in the case of cultured red sea bream, if the content of astaxanthin in the feed is low, the color of the epidermis becomes blackish and does not become the red color unique to natural red sea bream.
This has led to a decline in the commercial value of the farmed fish due to customs used to celebrate red and consumers' preference for red. Astaxanthin also has pharmacological effects such as antioxidation, and is considered to affect not only the appearance but also the quality of fish (eg, egg quality and meat quality of red sea bream).

Conventionally, when cultivating these fish, a raw material containing a high concentration of astaxanthin is added to the feed or as a feed, and the cultured fish is colored.

[0006] In recent years, astaxanthin has been used not only as a food for deep-coloring and coloring fish, but also for improving egg quality of quail, duck, chicken and the like.

[0007] Feed ingredients used for deep-friing fish include krill, shrimp, shrimp shells and crab shells, crushed oils, oily products extracted with oils and solvents, etc., decomposed cells of Phaffia rhodozyma or bacterial cells. Decomposed products or crushed products of green algae such as crushed products and Haematococcus are known.

[0008] Of these, krill and shrimp contain a large amount of water, so they must be stored frozen at the time of preservation, and must be dried when used as a compounded feed. Astaxanthin has a disadvantage that it is easily changed, and the deepening and coloring effects are significantly reduced.

[0009]

When a cell producing astaxanthin, such as Phaffia rhodozyma, is used as a feed, even if the cell is given to fish as it is, poor absorption of astaxanthin results in various methods. The method of decomposing or crushing the cells is adopted. Examples of the method include an acid hydrolysis method and a method of autolyzing cells (Biotechnology Letters V
ol. 6, No. 4, p. 247-250 (1984)
)], A method of lysing yeast cell walls using a lytic enzyme derived from a microorganism [Applied and Environmental Microbiology (Applied and Environmental Microbiology)]
Microbiology) Vol. 35, No. 6, p. 1155-
1159 (1978)], a mechanical treatment method of crushing bacterial cells using ultrasonic treatment, a French press, a homogenizer, and the like is known [Japanese Patent Laid-Open No. 57-206342].

[0010] Of these, in the acid hydrolysis method, the autolysis method and the cell lysis method using a lytic enzyme, astaxanthin itself is decomposed, and if mild treatment conditions are used to suppress the decomposition of astaxanthin, the cells may be degraded. It has the disadvantage of insufficient decomposition.

[0011] In addition, the method of disrupting cells by mechanical treatment has the disadvantage that the viscosity of the cell disruption treatment liquid itself becomes high and it is difficult to handle it in a subsequent step of feeding, such as drying. Moreover, the astaxanthin thus obtained is more easily oxidized and denatured than the untreated one, so that it is necessary to add an antioxidant or the like. It also requires special equipment,
In addition, processing costs are high, and there is an economical problem.

[0012]

Means for Solving the Problems Accordingly, the present inventors have used a process for producing astaxanthin-producing fungi such as Phaffia rhodozyma and making it suitable as a yeast for feed for improving the coloration of cultured fish. As a result of intensive research on the method, from the conventional tests, astaxanthin itself was considered unfavorable by an alkaline solution, the yeast cells were appropriately changed by selecting the treatment conditions, and astaxanthin in fish etc. It has been found that the absorbability can be significantly improved, and the present invention has been completed.

[0013] That is, the present invention relates to a food for seafood comprising a yeast having an improved ascending effect and usability of astaxanthin in yeast cells producing astaxanthin such as Phaffia rhodozyma.

The yeast for producing astaxanthin used in the present invention includes Phaffia rhodozyma.
In addition to bacteria belonging to Rhodozyma), any bacteria that produce astaxanthin can be used. Specifically, Phaffia Rodzima IFO 10129 strain,
IFO 10130 strain, ATCC 24201 strain and the like.

These bacteria are weakly acidic (pH 4 to 6) containing a carbon source of glucose, maltose, sucrose, molasses, organic and inorganic nitrogen sources such as yeast extract, malt extract, peptone, ammonium sulfate and other trace nutrients. 15 to 25 ° C. using a medium
It can be cultured under aerobic conditions (preferably 20 to 22 ° C).

After culturing the yeast, the yeast is treated with an alkaline solution. The cells to be treated are either the culture solution as it is or a concentrate thereof. Alternatively, a product obtained by separating and precipitating cells in a culture solution by centrifugation may be used.

In the present invention, a compound containing an alkali metal such as sodium or potassium, a compound containing an alkaline earth metal such as calcium or magnesium, or an organic base compound such as ammonia, methylamine or ethanolamine can be used as an alkaline solution having a pH of 10 or more. Alternatively, a buffer containing these can be used.

Examples of the compound containing an alkali metal include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate and the like. Examples of the compound containing an alkaline earth metal include calcium hydroxide and magnesium hydroxide.

As the buffer, any buffer having a pH of 10 or more can be used. Specifically, boric acid-sodium carbonate, ammonium chloride-ammonia, glycine-sodium hydroxide, bicarbonate, etc. Buffers such as sodium-sodium carbonate, borax-sodium hydroxide, borax-sodium carbonate, hydrochloric acid-sodium carbonate, disodium hydrogen phosphate-sodium hydroxide can be mentioned.

The method of treating the yeast cells with the alkaline solution may be any method as long as the alkaline solution and the yeast cells come into contact with each other. For example, the cells may be immersed in the alkaline solution. Alternatively, an alkaline solution may be sprayed on the cells.

FIG. 1 shows the relationship between the pH of the alkaline solution and the extraction rate of astaxanthin by alcohol from the treated cells when treated at room temperature for 1 hour. This is data to show that astaxanthin is easily released from the cells by the alkali solution treatment. In FIG. 1, a 0.1 M ginsine-sodium hydroxide buffer (●) was used for a pH of 12 or less, and an aqueous sodium hydroxide solution (〇) was used for a pH of 12 or more. The amount of astaxanthin extracted when the cells were mechanically crushed was defined as 100%.

As shown in FIG. 1, the pH of the alkaline solution
Is effective at pH 10 or more. If the pH of the alkali solution is too low, the treatment effect is not sufficient, and if the pH is too high, astaxanthin denaturation / decomposition easily proceeds. Therefore, the pH of the alkali solution is preferably 11 to 13.
The treatment can be carried out at a temperature of 0 to 130 ° C. However, if the temperature is high, the denaturation / decomposition of astaxanthin proceeds, and if the temperature is low, the treatment time needs to be extended. It is preferable to process at a temperature of The processing time may be 1 minute to 1 day, but is preferably 1 hour to 5 hours.

By performing the alkaline solution treatment, the yeast cells change, and the carbohydrate component in the cells decreases. This is considered to be due to the solubilization and decomposition of the contaminant polysaccharides and the like particularly on the cell surface by the alkali treatment. As a result, astaxanthin in the bacterial cells is easily absorbed by fish or the like that has consumed the food containing the bacterial cells, and as a result, the color deepening effect is enhanced.

After the treatment with the alkaline solution, the cells are separated from the alkaline solution by ordinary centrifugation or membrane separation, and if necessary, washing with water and the operation of separating the cells are repeated to obtain yeast for feed. Is preferred. Alternatively, instead of removing the alkaline solution, it is also possible to neutralize the alkaline solution with an acid to obtain feed yeast. in this case,
As the acid to be used, any acid can be used as long as a salt produced by a neutralization reaction with an alkaline solution is suitable as a feed. Specific examples include organic acids such as acetic acid, formic acid, and citric acid, and inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid.

The yeast for feed obtained as described above may be used as feed for cultured fish or the like as it is, but may be mixed with the composition of the compound feed as wet cells or as dry cells. And can be used as a compound feed.

Mixtures of commonly used feeds for cultured fish, such as fish meal, meat-and-bone meal, soybean oil cake, corn gluten meal, torula yeast, wheat flour, rice bran oil cake, minerals, vitamins, etc., form pellets or mashes. It can be formed into a compound feed.

In this case, the amount of yeast used in the present invention may be about 0.5 to 30% by weight, and is adjusted according to the astaxanthin content and the purpose of deep-coloring. In the case of preparing a compounded feed, the yeast for a feed prepared by the method of the present invention also has an advantage that the miscibility with the compound is better than the yeast cells prepared by a conventional method.

Next, a production example of the yeast used in the present invention will be described. Production Example A liquid medium containing 0.3% of yeast extract, 0.5% of polypeptone and 2.0% of sucrose was dispensed in four 50 ml portions into a 500 ml Erlenmeyer flask, and sterilized by heating in an autoclave at 120 ° C. for 20 minutes. One platinum loop of Phaffia rhodozyma (IFO10129 strain) was inoculated into this,
For 3 days to prepare a preculture.

Next, 20 liters of a liquid medium containing 0.3% of yeast extract, 0.5% of polypeptone, and 2.0% of sucrose was placed in a 30 liter jar fermenter and sterilized by heating at 120 ° C. for 20 minutes. This was inoculated with 200 ml of the preculture solution, and cultured at 25 ° C. for 5 days.

About 200 ml of 10N sodium mercury was added to the obtained culture solution (pH 4.5) to adjust the pH to 12.5, left at room temperature for 1 hour, neutralized with hydrochloric acid, and centrifuged to separate cells. Is separated and dried with a spray drier for about 1
30 g of alkali-treated Phaffia yeast was obtained.

On the other hand, after completion of the culture, the yeast cells were centrifuged without alkali treatment, and the yeast cells were dried with a spray drier to obtain about 160 g (untreated Phaffia yeast).

[0032]

Next, the present invention will be described in more detail with reference to examples, but the examples do not limit the present invention in any way.

Example 1 Using each of the Phaffia yeasts produced according to the Production Examples, the compounded feed shown in Table 1 was prepared, and a test for deep-sea red sea bream was performed.

[0034]

[Table 1]

Test period April 16 to June 18, 1990 Test fish Red sea bream with an average body weight of about 40 g and a uniform body weight were used in 10 fish per experimental plot. Breeding conditions Breeding water: seawater (20-25 ° C) Feeding: daily twice in the morning and evening

Method for judging coloration effect Measurement of astaxanthin content on body surface After the rearing test, the skin of red sea bream was peeled off. The peeled epidermis was cut finely, and the crude carotenoid was extracted with acetone. The crude carotenoid extract was concentrated under reduced pressure, and petroleum ether was added to dissolve the carotenoid. This petroleum ether solution was washed with water, dehydrated with anhydrous sodium sulfate, and then concentrated under reduced pressure. The concentrate is passed through a celite silicate column, the carotene fraction is removed by leaching with ether / petroleum ether (5:95), and ethyl acetate / petroleum ether (4: 6).
To elute the astaxanthin fraction. The eluted astaxanthin fraction was concentrated and made up to constant volume with petroleum ether.
The absorbance at 70 nm was measured, and the specific extinction coefficient was E ^{1 *} = 2400
Was used to determine the amount of astaxanthin.

Table 2 shows the results of the test.

[0038]

[Table 2]

The red sea bream reared on the blended feed (feed category 3) using the alkali-treated Phaffia yeast cells according to the present invention has a markedly red body surface compared to the untreated Phaffia yeast added feed (feed category 2) red sea bream. Is increasing. In addition, it has the same level of color deepening effect as red sea bream bred with a feed (feed category 4) containing krill meal as a control plot.

[0040]

According to the present invention, it is possible to provide a food excellent in the effect of deepening fish and shellfish.

[Brief description of the drawings]

FIG. 1 shows the pH of an alkaline solution and the extraction ratio of astaxanthin with alcohol from treated cells.

Claims (1)

(57) [Claims] 1. A feed for cultured fish and shellfish, comprising a yeast cell producing astaxanthin treated with an alkaline solution having a pH of 10 or more.