JPH0330637A - Method for improving body color of cultured fish - Google Patents

Abstract

PURPOSE:To improve the body color of a cultured fish to a desirable color by breeding a fish with a feed containing kojic acid. CONSTITUTION:Body color of a cultured fish such as sea bream, eel or fancy fish can be improved by breeding the fish with a feed containing kojic acid and preferably astaxanthin. The amount of kojic acid to be applied to the cultured fish is preferably 10-100mg daily per 1kg of the fish.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for improving the body color of farmed fish, and more specifically, the present invention relates to a method for improving the body color of farmed fish, and more particularly, the present invention relates to a method for improving the body color of farmed fish by administering to the fish a feed containing kojic acid or kojic acid and astaxanthin. Regarding improvement methods.

[Conventional technology]

Currently, methods for improving the body color of farmed fish are available for farmed red sea bream, farmed eel,
It is desired as an ornamental fish.

In the case of farmed red sea bream, the bright red color fades and takes on a blackish tinge compared to wild red sea bream. Conventionally, as a remedy for this problem, body color has been improved by blocking sunlight with a shade net or the like. Additionally, astaxanthin is added to feed for coloring purposes.

In the case of farmed eels, greenish eels are preferred by restaurants and the like as a luxury item and are therefore more expensive, but their body color is darker than that of wild eels, and no particular measures have been taken to address this problem.

In the case of ornamental fish such as goldfish and colored carp, in order to bring out the bright colors on the white background, a lot of effort is taken to manage the quality of the breeding water in order to cultivate phytoplankton in the pond water.

[Problem to be solved by the invention]

For farmed red sea bream and farmed eel, it is desired to improve the body color to be more similar to natural color, and for ornamental fish such as goldfish and colored carp, it is desired to save the effort of management and to make the color of the white background more vivid.

[Means for Solving the Problems] The present inventors have investigated various effective methods for improving the body color of farmed fish, and as a result, the addition of kojic acid to feed exhibits a remarkable body color improvement effect. In addition, in the case of farmed red sea bream, we found that adding kojic acid and astaxanthin in combination to the feed can further improve body color.

When carrying out the present invention, the dosage of kojic acid to cultured fish is 1 mg to 100 kojic acid per day per 1 kg of cultured fish.
It is desirable to administer 0 mg, preferably 10 mg to 100 mg. The dosage of astaxanthin used in combination is preferably 0.05 mg or more, preferably 0.3 mg or more per day per cultured red sea bream weighing 1 kg. As a source of astaxanthin, krill, rockfish, etc. may be directly fed, or their extracted oils may also be used.

If the amount of kojic acid is too large, it may cause a bitter or astringent taste, which may reduce appetite, and if it is too small, the body color improving effect may not be sufficiently exerted.

In addition, it is desirable that the administration be continued for 5 days or more, preferably 20 days or more, before shipping. Although there is no problem with administration for longer than that, a sufficient body color improvement effect cannot be expected if the administration period is less than 5 days.

〔effect〕

According to the method of the present invention, by feeding cultured fish with kojic acid or feed containing kojic acid and astaxanthin, it is possible to improve the body color to a desirable level.

Example 1 Cultured red sea bream was raised under the following conditions and changes in body color were observed.

Feed 70% fishmeal, 25% wheat flour, 2% vitamins and minerals, 1% sodium alginate, C, M, C, 2%
One part of raw feed (minced sardine) was mixed with one part of the mixed feed consisting of the following, to prepare a feed supplemented with tudic acid.

Test fish: Cultured red sea bream, weight 500g ± 50g Test area A
, B, C, control groups. Feeding 2 fish by weight each. Control group administered 20g once a day under the following conditions. Kojic acid-free compound feed test group A. 0.01% kojic acid-containing compound feed test group B.
O05% Kojic Acid Containing Compound Feed Test Group C10% Kojic Acid Containing Compound Feed Rearing Period 50 Days Example 2 Cultured red sea bream were reared under the following conditions and changes in body color were observed.

Feed 70% fishmeal, 25% wheat flour, 2% vitamins and minerals, 1% sodium alginate, C, M, C, 2%
A feed for adding kojic acid and astaxanthin was prepared by mixing 1 part raw feed (minced sardine) to 1 part mixed feed.

Krill extract oil was used as astaxanthin.

Test fish: Cultured red sea bream, weight 500g ± 50g Test area A
, B, C, D, 3 each, 12 fish in total, fed 20 g once a day per fish Test area ABCD Kojic acid 0.5χ 0.5χ 0.5χ7
Star material tintin -1.5mgχ 0.5mgχ
3mgχ Breeding period: 50 days Pung 23%, vitamins and minerals 2%, beer yeast 5%
1.0% kojic acid is added to the compound feed consisting of the following, and 130 parts of water is added to 100 parts of the compound feed to make a kneaded feed.

Test fish: 10 farmed eels in test and control areas, average body length 15 cm. Feeding: Place the above-mentioned kneaded food in a feeding box so that it can be weighed at all times.

Breeding period: 50 days Example 3 Cultured eels were raised under the following conditions and changes in body color were observed.

Feed White Fitzschmeal 70%, Alpha Den Breeding 5
A slight change in body color was observed after 20 days, and a clear change was observed after 20 days.

Example 4 Nishikigoi were raised under the following conditions and changes in body color were observed.

Feed A mixed feed consisting of 63% fishmeal, 35% wheat flour, and 2% vitamins and minerals was used.

0.02% kojic acid was added to the test plot to form dry pellets.

Test fish: Nishikigoi 3 fish each in test area and control area Weight: 200g±50g Feeding once a day The dosage is 10g per day for one Nishikigoi. Breeding period: 50 days

Claims (1)

[Claims] (1) A method for improving the body color of farmed fish, which is characterized by raising farmed fish with feed containing kojic acid. (2) A method for cultivating cultured fish, which is characterized by raising farmed fish with feed containing kojic acid and astaxanthin. How to improve body color of red sea bream