JP2005013116A - Feed for eel fingerling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide feed for eel fingerling for growing/metamorphosing eel fingerling to elver. <P>SOLUTION: The feed for eel fingerling contains a krill decomposition product and/or a soy peptide subjected to phytic acid decreasing treatment. The krill decomposition product is such one as to use krill intrinsic enzymes for decomposition treatment and be further heated and degenerated. The soy peptide subjected to phytic acid decreasing treatment is obtained by making protease and phytase act on soy proteins, and contains not more than 1 wt.% of phytic acid. The feed can grow eel fingerling to elver and is formulated with the egg component of a living thing. The egg component is derived from fish egg or hen's egg. The feed contains highly unsaturated fatty acid-containing oil and fat. Eel seeds and saplings are raised using the feed for eel fingerling. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a eel larvae feed that is indispensable for the production of eel seedlings containing soybean peptides treated with krill and / or phytic acid reduction. More specifically, the present invention relates to a eel larvae feed that contains soybean peptides treated with krill and / or phytic acid reduction and can grow eel larvae to glass eels. The present invention also relates to an eel seedling grown using these eel larvae feeds.
[0002]
[Prior art]
Eels are important aquaculture species with high production, but all seedlings depend on natural white eels. Therefore, the trading price of glass eels fluctuates greatly depending on the amount of catch, contributing to the destabilization of sericulture management. Eel seedling production, that is, if glass eels can be stably mass-produced in captivity, will contribute not only to stabilization of sericulture management but also to the protection of eel resources that have been rapidly decreasing in recent years. Now that eels can be artificially hatched, it is necessary to develop feed that grows and transforms larvae into glass eels.
[0003]
Natural eels are often enveloped in mysteries such as maturation, spawning grounds, hatching and larval growth. After hatching, eels grow from preleptocephalus to leptocephalus and then dramatically transform into glass eels. A large number of natural leptocephalus has been collected so far, and studies on gastrointestinal retention have been carried out, but the diet of leptocephalus is still unclear.
[0004]
More than 20 years have passed since the eel artificial hatching became possible, and so far there are a lot of biological foods such as rotifers, commercial early feeds, commercial fortified feeds, seafood gonads and chicken eggs, etc. The substance has been tried. However, for the initial feed of eel larvae, other than the knowledge (Patent Document 1) that the shark egg powder found by the research group of the National Fisheries Research Center In spite of many attempts so far, no feed has been found that has feeding incentive and growth potential for eel larvae. Moreover, even with the shark eggs described above, it has been impossible to grow and transform Leptocephalus to shirasu.
[0005]
Subsequently, eel larvae were successfully grown to leptocephalus with a sedimentary feed containing soy peptide, vitamin mix, mineral mix, and krill water extract in shark egg powder (Non-patent Document 1). Even the glass eel did not grow or metamorphose.
[0006]
By the way, it is known that Antarctic krill ( Euphausia superba ) is excellent in growth and feeding as a food for seafood. Antarctic krill as a raw material for fish feed is used as feed for breeding, and its utilization is raw or meal. As described above, the effectiveness of the krill water extract as a feed raw material for eel larvae has been shown, but it cannot be said that the functionality of krill has been fully utilized. However, in the form of use such as raw or meal, the functionality of krill could not be utilized to the maximum for eel larvae with weak digestive absorption ability.
[0007]
Moreover, although the effectiveness to the feed raw material of a soybean peptide has already been confirmed (nonpatent literature 1), it has not reached the feed which can grow an eel larva to a glass eel.
In addition, as a method for removing phytic acid from soybean, a method for removing phytic acid in a water extraction process of soybean protein using a salt (Patent Document 2, Patent Document 3), a method of decomposing phytic acid with phytase or the like And a method of removing it by adsorbing it to a resin or the like (Patent Document 4).
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-253111 [Patent Document 2]
Japanese Patent Laid-Open No. 8-173052 [Patent Document 3]
JP-A-9-121780 [Patent Document 4]
JP 2001-163800 A [Non-Patent Document 1]
Tanaka et al., Production of Leptocefari of Japanese eel (Anguilla Japonica) in Capability (Production of leptocephali of Japan) (Anguilla japonica) Culture in the Netherlands ELSEVIER SCIENCE BV, September 14, 2001, 201, 1-2, p. 51-60
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a feed for eel larvae that can grow and transform eel larvae to white eels.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have conducted intensive research. As a result, a feed containing a krill degradation product and / or a soy peptide reduced in phytic acid has a feeding-inducing property and growth potential for eel larvae. I found out that I had this and completed this research.
[0011]
The present invention relates to a krill decomposition product, preferably a krill decomposition product using a krill endogenous enzyme in the decomposition treatment, a krill decomposition product that is denatured by an endogenous enzyme and then heat-denatured, and / or soybeans reduced in phytic acid. Eels containing peptides, preferably those obtained by allowing protease and phytase to act on soy protein, more specifically, phytic acid-reduced soy peptide having a phytic acid content of 1% or less of the soy peptide The main point is the feed for larvae.
The present invention is a feed that can grow eel larvae to glass eels.
[0012]
In addition, the present invention contains a biological egg component, preferably an egg component derived from a fish egg or a chicken egg, and, if necessary, a highly unsaturated fatty acid-containing fat in addition to a krill degradation product and / or a phytic acid-reduced soybean peptide. The essence is feed for eel larvae.
In addition, the present invention provides a krill decomposition product, preferably a krill decomposition product using a krill endogenous enzyme for the decomposition treatment, a krill decomposition product that is heat-denatured after being decomposed by the endogenous enzyme, and / or a phytic acid reduction treatment. Soy peptide, preferably obtained by allowing protease and phytase to act on soy protein, more specifically, soy peptide reduced in phytic acid content is 1% or less of the soy peptide as phytic acid content Eel seed seedlings grown using eel larvae feed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the eel larvae to be the subject of the present invention include eel larvae to be cultured such as Japanese eel ( Anguilla japonica ) and European eel ( Anguilla anguilla ). The eel larvae referred to in the present invention refers to eel larvae at a stage prior to transformation into a glass eel such as pre-leptokephales and leptokephales.
Examples of the krill used in the present invention include industrially useful krill ( Euphausiacea ), and it is preferable to use Antarctic krill ( Euphausia superba ). As for this krill, a degradation product obtained by endogenous enzymes (autolyzed product) or a degradation product obtained by externally adding a commercially available enzyme and enhancing degradation by endogenous enzymes may be used. The krill decomposition product can be obtained, for example, by maintaining the heating at 50 ° C. for 1 hour with minced krill. Further, a krill decomposition product heat-denatured by a conventional method may be used.
[0014]
The phytic acid-reduced soybean peptide (hereinafter referred to as “low phytic soybean peptide”) used in the present invention is described below.
First, methods for removing phytic acid from soybean include (1) removing phytic acid in the process of aqueous extraction of soybean protein using a salt (Patent Documents 2 and 3 above), (2) phytate with phytase, etc. There is a method of decomposing, (3) a method of removing it by adsorbing it to a resin or the like (Patent Document 4), and the method of (2) is less complicated than the methods of (1) and (3). Is advantageous. A low phytin soy peptide can be produced by proteolysis by causing a protease to act on a raw material reduced in phytin by such a method. It should be noted that hypophytization and protease degradation can be performed first or simultaneously. Although it is desirable to completely remove the remaining phytic acid, the amount of the remaining phytic acid is usually 1.0% or less as determined by vanadomolybutenoic acid spectrophotometry (detection limit 5 mg / 100 g), and is preferably 0.8. 5% or less.
[0015]
The proteolytic enzyme (protease) used in the present invention can be exoprotease or endoprotease alone or in combination, regardless of animal origin, plant origin or microbial origin. Specifically, serine protease (animal-derived trypsin, chymotrypsin, microbial-derived subtilisin, carboxypeptidase, etc.), “Protin FN” (produced by Daiwa Kasei Co., Ltd.) derived from Aspergillus oryzae, “Protease S” (Amano Pharmaceutical) And Protin AC-10 (manufactured by Daiwa Kasei Co., Ltd.).
[0016]
The hydrolysis conditions of the present invention vary somewhat depending on the type of proteolytic enzyme to be used. In general, an amount sufficient to hydrolyze soy protein that has been reduced in the phytase in the working pH range and temperature range. It is good to use. The degree of hydrolysis is about 5 to 98%, more usually about 50 to 90% of soybean protein degradation rate in terms of 15% trichloroacetic acid solubility of protein components. The time for which the protease is allowed to act is usually about 5 minutes to 12 hours, preferably about 30 minutes to 5 hours, although it depends on the activity and amount of the protease used. If the enzymatic degradation time is too long, it tends to cause spoilage.
[0017]
Examples of egg components used in the present invention include those derived from fish eggs or chicken eggs. Examples of fish eggs include shark eggs, sukeko, madarako, red sea bream eggs, and shark eggs are particularly preferred. These may be either liquid eggs or powders, but it is particularly preferable to use liquid eggs.
The highly unsaturated fatty acid-containing fat used in the present invention may be of animal origin, plant origin or microbial origin. Specific examples include sardine feed oil, cod liver oil, and refined fish oil containing ω-3 and ω-6 highly unsaturated fatty acids at high concentrations.
[0018]
The feed for eel larvae of this invention is manufactured by mixing the above-mentioned component suitably. At this time, the krill degradation product and the low phytic soybean peptide may be used alone or in combination. In any case, the blending amount is not limited, but the krill decomposition product is 3 to 50% and the low phytic soy peptide is 3 to 50% and can be used in combination as appropriate. For example, a combination such as 20% egg component, 3% krill degradation product, 3% low phytic acid soybean peptide, 4% DHA-rich oil, and 70% distilled water can be used.
[0019]
[Action]
The present invention is a feed for eel larvae characterized by comprising a krill degradation product, preferably a krill degradation product using a krill endogenous enzyme for degradation treatment and / or a low phytic soybean peptide. By using Antarctic krill and / or low phytin soy peptide as feed or feed material, it is possible to grow and transform eel artificially hatched larvae to white eel.
[0020]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited by these examples.
[0021]
Example 1
Tests to confirm the growth of eel larvae by various components <br/> Eating eel larvae 8 days after hatching, which hatched from fertilized eggs obtained by artificial ripening and formed eyes and mouth organs and became ready for feeding It was fish. Twelve 5 L acrylic bowl-shaped aquariums were used, each containing approximately 200 eel larvae. The breeding water temperature was 21.5 ° C. Since the number of days without feeding was around 15 days after hatching, the feeding period was set to 10 days.
The test plots were shark egg feeding zone (feed 1), shark egg + low phytic soy peptide zone (feed 2), shark egg + krill degradation product zone (feed 3), and shark egg + low phytic soybean peptide + krill degradation zone. (Feed 4). Table 1 shows the feed composition. The shark egg liquid egg has a water content of 50%.
[0022]
[Table 1]
[0023]
The feed feeding method is disclosed in JP-A-11-253111 (Patent Document 1) and Tanaka et al. [Non-Patent Document 1 (H. Tanaka, H. Kagawa, H. Ohta, Accuculture 201 (2001) 51-60). ]. That is, about 5 ml was injected with a Komagome pipette into the bottom of a water tank prepared on the day before or on the day of feeding and stored at 0 to 1 ° C., and the water injection was stopped immediately before feeding. Temperature-controlled filtered seawater was injected at 0.4 L / min 30 minutes after feeding, and the inside of the aquarium was kept clean by pouring the breeding seawater. The number of feeding was 5 times a day, every 2 hours, and the larvae were moved to a clean water tank using a siphon at night every day. For statistical processing of breeding results, Tukey multiple comparison was performed for items that were significant by analysis of variance. The results are shown in FIG. 1 (survival rate of eel larvae in each test section), FIG. 2 (effect of krill degradation product and low phytic acid soybean peptide on the total length of eel larvae), and FIG. 3 (krill degradation product and low phytic acid soybean peptide). (Effects of eel larvae on body height), FIG. 4 (effects of krill degradation products and low phytic acid soy peptide on body height / full length of eel larvae), and Table 2 (feeding results on growth).
[0024]
As a result, the larvae showed good food intake and grew well with any feed. The average survival rate after 10 days of feeding was 33.1% for feed 1, 38.2% for feed 2, 37.7% for feed 3, and 54.7% for feed 4. Survival rates were higher when shark eggs and krill degradation products or diets containing shark eggs and low phytin soy peptide were fed than shark eggs alone. Furthermore, the highest survival rate was obtained when shark eggs, krill degradation products and low phytin soy peptide were added.
[0025]
The average total length of the larvae at the start of feeding was 6.65 ± 0.26 mm. The average total length of each test group 10 days after feeding was 8.25 ± 0.56 mm for feed 1, 8.53 ± 0.66 mm for feed 2, 8.88 ± 0.64 mm for feed 3, and 8. It was 97 ± 0.55 mm. The feeding effect was recognized for all feeds, and the overall length was significantly (p <0.01) longer than that at the start of feeding. The feed blended with shark egg and krill degradation product and the feed blended with shark egg and low phytin soy peptide significantly increased in total length compared to shark egg alone (p <0.01). Furthermore, when the shark egg, krill decomposition product and low phytin soy peptide were blended, the full-length elongation was shown.
[0026]
Body height was measured to evaluate the body shape of eel larvae. Typical leptocephalus has a high body height and a large body height / body length ratio. The average height of the larvae at the start of feeding was 0.65 ± 0.05 mm. The average height of each test group 10 days after feeding was 0.82 ± 0.08 mm for feed 1, 0.85 ± 0.10 mm for feed 2, 0.95 ± 0.11 mm for feed 3, and 0. It was 97 ± 0.11 mm. The feeding effect was recognized for all the feeds, and the body height was significantly higher (p <0.01) than when feeding was started. When the feed containing the shark egg and krill degradation product was fed, the body height was significantly higher than when the shark egg alone or the shark egg and soybean peptide was added (p <0.01). Furthermore, when the shark egg, soybean peptide, and krill degradation product were blended, the body height was the highest.
[0027]
The body height / length (%) of each test group was 9.79 ± 0.48% at the start of the test, 9.91 ± 0.68% for feed 1, 9.91 ± 0.67% for feed 2 and feed 3 was 10.75 ± 0.83% and feed 4 was 10.78 ± 0.92%. It was shown that the feeding of the feed containing the krill degradation product was significantly increased with respect to the height / length ratio (p <0.01).
From the above results, it was confirmed that the eel larvae were significantly grown by the combination of the fish egg component and the krill degradation product, the low phytin soy peptide, or a combination thereof.
[0028]
[Table 2]
[0029]
Example 2
Test for confirming growth by the difference in egg components Larvae hatched from fertilized eggs obtained by artificial ripening and formed eyes and mouth organs and became feedable were used 8 days after hatching. Eel larvae were housed in a 20 L acrylic water tank. The breeding water temperature was 21.5 ° C.
The test plots were feed 5 fed with shark egg powder, low phytic soy peptide and krill degradation product, chicken egg powder, low phytic soy peptide, krill degradation product, and ω-3 high-purified fish oil (DHA content) 46%), feed 6 was obtained. Table 3 shows the feed composition. The feed feeding method was the same as in Example 1.
[0030]
[Table 3]
[0031]
So far, eel larvae have not been observed to grow except for feed containing shark eggs. However, the larvae showed good food intake even with the feed 6 containing no shark egg powder and grew smoothly. When the average total length on the 28th day after hatching was compared, the feed 5 was 9.85 ± 0.70 mm and the feed 6 was 9.43 ± 0.89 mm (FIG. 5). The total length of the longest individual 28 days after hatching was 10.9 mm for feed 5 and 11.0 mm for feed 6.
[0032]
According to Tanaka et al. Using shark egg powder-based feed [Non-Patent Document 1 (H. Tanaka, H. Kagawa, H. Ohta, Accuculture 201 (2001) 51-60)], larvae obtained by artificial insemination are It has grown to 10.6 mm 25 days after hatching. From the results of this test, the feed 6 containing chicken egg powder, krill degradation product, low phytin soy peptide and fish oil also showed growth comparable to the growth of feed 5 which is a feed containing shark eggs.
[0033]
In the feed of the present invention, many individuals exceeding 10 mm are observed 28 days after hatching, and the feed containing chicken egg powder, krill degradation product, low phytic soy peptide and fish oil can be sufficiently comparable to shark egg powder-based feed Was confirmed.
[0034]
Example 3
Test for confirming metamorphosis to glass eel The larvae 8 days after hatching, which hatched from fertilized eggs obtained by artificial ripening and formed eyes and mouth organs, were made available. Eel larvae were housed in a 20 L acrylic water tank. The breeding water temperature was 21.5 ° C. Table 4 shows the feed composition. The shark egg liquid egg has a water content of 50%. Feed 7 was fed until 18 days after hatching, and feed 8 was fed from 19 days after hatching.
[0035]
[Table 4]
[0036]
As a result, the larvae grow smoothly, reach a total length of 50 to 60 mm about 7 to 9 months after hatching, start transformation from Leptocephalus to glass eel, and about 2 to 2 except for individuals whose bodies are curved during transformation. It was confirmed that the whole length was shortened by 2 to 8% in 3 weeks and transformed into glass eel (FIGS. 6 and 7).
[0037]
【The invention's effect】
According to the present invention, it has become possible to provide an excellent eel larvae feed that can grow eel larvae to white eels.
[Brief description of the drawings]
FIG. 1 shows a shark egg feeding group (feed 1), a shark egg + low phytin soybean peptide group (feed 2), a shark egg + krill degradation product group (feed 3), and a shark egg + low phytin soybean peptide in Example 1. + Survival rate comparison of krill degradation product section (feed 4).
FIG. 2 shows a shark egg feeding group (feed 1), a shark egg + low phytin soy peptide group (feed 2), a shark egg + krill degradation product group (feed 3), and a shark egg + low phytin soybean peptide in Example 1. + Comparison of the total length (mm) of the krill decomposition product (feed 4).
FIG. 3 shows a shark egg feeding group (feed 1), a shark egg + low phytin soy peptide group (feed 2), a shark egg + krill degradation product group (feed 3), and a shark egg + low phytin soybean peptide in Example 1. + Body height (mm) comparison of krill decomposition product group (feed 4).
4 shows a shark egg feeding group (feed 1), a shark egg + low phytin soy peptide group (feed 2), a shark egg + krill degradation product group (feed 3), and a shark egg + low phytin soybean peptide in Example 1. FIG. + Comparison of body height / full length (%) of the krill decomposition product group (feed 4).
FIG. 5 shows the total length (mm) of shark egg powder + low phytic soy peptide + krill degradation product (feed 5) and chicken egg powder + low phytic soy peptide + krill degradation product + fish oil division (feed 6) in Example 2. ) Transition comparison.
FIG. 6 shows growth and transformation of larvae in Example 3.
7 shows an example of metamorphosis of larvae in Example 3. FIG. Same individuals from 248, 254, 262 days after hatching from above.

Claims (10)

A feed for eel larvae containing a krill degradation product and / or a soybean peptide reduced in phytic acid. The feed for eel larvae of Claim 1 whose krill decomposition product is a krill decomposition product which used the krill endogenous enzyme for a decomposition | disassembly process. The feed for eel larvae of Claim 1 or 2 whose krill decomposition product is further heat-denatured. The eel larvae feed according to claim 1, 2 or 3, wherein the soybean peptide subjected to the phytic acid reduction treatment is obtained by allowing protease and phytase to act on soybean protein. The feed for eel larvae according to any one of claims 1 to 4, wherein the phytic acid-reduced soybean peptide has a phytic acid content of 1% or less of the soybean peptide. The feed for eel larvae according to any one of claims 1 to 5, wherein the eel larvae are feeds that can be grown to glass eels. Furthermore, the feed for eel larvae in any one of Claim 1 thru | or 6 which mix | blended the egg component of the organism. The feed for eel larvae according to claim 7, wherein the egg component is derived from fish eggs or chicken eggs. Furthermore, the feed for eel larvae in any one of Claim 1 thru | or 8 containing highly unsaturated fatty acid containing fats and oils. An eel seedling grown using the feed for eel larvae according to claim 1.