JPS5944020B2 - How to raise marine fish using oleaginous yeast - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a feed (hereinafter referred to as microfeeding organisms) used for cultivating microorganisms that serve as feed for young larval fish and juvenile crustaceans (hereinafter referred to as larval fish, etc.). The present invention relates to a method of cultivating microorganisms using microorganisms, and a method of cultivating fish, crustaceans, shellfish, etc. (hereinafter abbreviated as fish and shellfish), especially young fish, etc., using these organisms.

Conventionally, in the cultivation of fish and shellfish, supplying young fish, etc. has been accompanied by various problems, and a stable supply method has been required.

In other words, for many artificially acetylated fish species, the first food is given to them as a rotifer, an oyster larva, a fertilized sea urchin egg, etc., and then a water flea, a water flea, a water flea, a brine shrimp, etc. etc. are given.

These zooplankton are living organisms, and in order to farm young fish, etc., it is first necessary to farm these zooplankton.

Regarding these micro-prey organisms, there are reports on the relationship between the nutritional value of micro-prey organisms and that of wild adult fish.

Aquatic feed biology (written by Akihiko Shirota, published by Kouseisha Koukaku).

However, no study has been found that examines the relationship between essential nutrients for young fish and other microorganisms.

The present inventors have discovered that the nutritional value of microscopic food organisms given when cultivating young fish, etc. is reflected in the young fish, etc., and that the nutritional value of microscopic food organisms is We found that it was influenced by nutritional value.

In other words, when rotifers, which are used as microfeeding organisms, are fed marine chlorella or baker's yeast, their body composition changes depending on the nutritional value of the marine chlorella or baker's yeast, and the change is particularly obvious in fatty acids, which are important nutritional values for fish. .

That is, marine chlorella contains the omega-3 highly unsaturated fatty acids eicosapencitric acid (20:5), eicosatrienoic acid (20:3), eicosatetraenoic acid (20:4),
Baker's yeast contains docosahexaenoic acid (22:6), docosapene citric acid (22:5), etc., whereas baker's yeast has a low content of these ω-3 polyunsaturated fatty acids, and rotifers cultured using it The content of these ω-3 highly unsaturated fatty acids does not meet the requirements of young fish, etc.

The present inventors cultivated rotifers containing sufficient amounts of higher fatty acids, especially omega-3 highly unsaturated fatty acids, required by fry, etc., and when culturing fry, etc. using these rotifers, the superiority of fry, etc. The present invention was completed based on the discovery that a higher survival rate and growth rate could be obtained.

According to the present invention, ω-3 highly unsaturated fatty acids or their esters (hereinafter referred to as ω-3 HUFA) are added to yeast from 2.0 to
Good results can be obtained by feeding a feed supplemented with 5.0% to microscopic feed organisms such as rotifers and cultivating them, and then cultivating young fish and the like using the feed organisms.

As the yeast used, yeast of the genus Satucharomyces, such as baker's yeast and brewer's yeast, is used.

As the ω-3 highly unsaturated fatty acid, an unsaturated fatty acid having 20 or more carbon atoms and an unsaturated bond in the ω-3 position can be used.

In this specification, C20: 5 ω3 indicates the number of carbon atoms (20), the number of unsaturated bonds (5), and the position of the unsaturated bonds (ω-3).

Specific examples of these include eicosahexaenoic acid CH3
CH2(CH=CHCH2)4(CH2)5COOHC
20:4 ω-3 eicosaben citric acid CH3CH
2(CH=CHCH2)5(CH2)2COOHC20
:5 ω-3 docosapene citric acid CH3CH2 (
CH=CHCH2) 5 (CH2)4 COOHC2
2: 5 ω-3 docosahexaenoic acid CH3CH2
(CH=CHCH2)6CH2COOHC22,6ω-
3, and examples of the ester include alkyl esters.

These ω-3 HUFAs are contained in large amounts in the oils of fish and shellfish, and can be separated from these by known techniques such as molecular distillation and column chromatography.

These ω-3HUFAs can be used alone or in combination.

However, mixtures containing these without separation, such as the above-mentioned fish and shellfish, can be advantageously used.

Fish and shellfish used include cod, roe, sardines, sea bream, clams,
Mussels, scallops, etc. are used.

Yeast feed containing ω-3HUFA will induce ω-3HUFA in yeast.
Although it is sufficient to mix FA or its contents, by adding 3-3HUFA or its contents to the medium during yeast cultivation, a product in which 3-3HUFA or its contents are taken into the bacterial cells or adsorbed to the bacterial cells can be obtained.

When cultivating microfeed organisms using the ω-3HUFA-containing yeast feed, normal aquaculture methods are applied.

Examples illustrating aspects of the present invention are shown below.

Example 1: Baker's yeast (Saccharomyces cer
Squid liver oil molecular distillation residue oil was added to the culture at the final stage of the culture of S. evis 1ae) in an amount of 15% of the amount of bacterial cells (wet weight), and after 10 hours, the bacterial cells were collected by centrifugation.

When this bacterial cell was examined under a microscope, it was found that the bacterial cell membrane contained a large amount of oil and fat, and analysis showed that it had a lipid content 1.5 times that of baker's yeast.

Also, its constituent fatty acids include C, which is an ω-3 highly unsaturated fatty acid.
20:5tC22:5 and C22:6 were included at 15% or more of the total fatty acid amount, and these ω-3 polyunsaturated fatty acids were hardly observed in baker's yeast itself.

This oil-containing yeast was used for rearing Shiomizu rotifers.

That is, 1 m3 of seawater temperature 22°C (ratio] i1.022)
When we cultured 100 rotifers per 11 rL in an aquarium under aeration and suspended oil-containing yeast at a rate of 1 g/106 rotifers/day, the rotifers ingested this and grew steadily every day. We were able to collect 20% continuously.

That is, 2 rotifer individuals/day could be collected over 10 days or more.

When the constituent fatty acids of this rotifer were compared with those of rotifers fed baker's yeast in the same manner, differences in the constituent fatty acids were observed as shown in the table below.

These rotifers were fed to young red sea bream, rock bream, and black sea bream starting on the 5th day after breeding, and the growth, survival rate, etc. were compared, and the following results were obtained.

The strength of the construction is reduced by taking up the reins and exposing it for 5 seconds (after 24 hours)
were counted and measured.

Example 2 In Example 1, cod liver oil was used instead of squid liver oil, and after culturing the yeast, it was added to the bacterial cells at the time of bacterial collection to produce oil-containing yeast.

When this product was given at the same concentration to rotifers previously raised with baker's yeast in a 1 m3 water tank similar to that used in Example 1, and analyzed 12 hours later, changes in lipid-constituting fatty acids were observed as shown in the table below.

When these rotifers were fed to young sweetfish larvae from 3 days after emergence, the survival rate and growth of the fish were compared, and as shown in the table below, it was clear that the rotifers that had ingested the oil-containing yeast rotifers were superior.

Claims (1)

[Scope of Claims] 1. A feed for microfeeding organisms comprising yeast containing an omega-3 (omega-3) highly unsaturated fatty acid or its ester. 2. A method for growing and culturing microfeed organisms using a feed for microfeed organisms consisting of yeast containing omega-3 (omega-3) highly unsaturated fatty acids or esters thereof. 3. A method for cultivating fish and shellfish using microfeed organisms cultured using microfeed organisms feed consisting of yeast containing omega-3 (omega-3) highly unsaturated fatty acids or esters thereof.