JP6618109B2 - Feed for larvae containing raw shirasu and method for producing the same - Google Patents

Description

  The present invention relates to a feed for larvae prepared by degrading a fish protein degradation product with raw shirasu and a method for producing the same.

  Fishery resources are decreasing year by year due to overfishing and weather fluctuations. For this reason, the production of marine products by aquaculture has increased dramatically since the latter half of the 20th century.

However, in order to cultivate, it is necessary to know the ecology of the target organisms. Although fully managed aquaculture is carried out, the bluefin tuna and eel, which are in high demand in Japan, have many unclear ecology from hatching to fry, and in recent years, some fully-cultured tuna have begun to circulate. The current situation is that most of them catch natural fry and use them as seedlings.
Bluefin tuna and eel are both endangered species, and complete aquaculture is desired from the viewpoint of resource conservation.

  In eel aquaculture in which natural white eels are used as seedlings, in order to establish artificial seedling production technology, it is necessary to develop an efficient breeding method for growing the hatched larvae to glass eels, which are conventional seedlings for aquaculture.

Development of mass production technology for artificial glass eels is indispensable for the sustainable development of the Japanese eel aquaculture industry. However, for the mass production of artificial glass eels, the development of stable feed larvae is an important issue. is there.
Shark egg powder (Patent Document 1) has been proposed as an initial feed for eel larvae, and it has been confirmed that a krill decomposition product is first transformed into a white eel (Patent Document 2). As described above, the blackfish shark egg is the main ingredient of the feed for eel larvae. However, in the case of feed using natural resources as a raw material, it is difficult to provide a large amount and a stable supply. In particular, there is anxiety about the stable supply in the future for the black shark egg due to the depletion of the amount of resources.

  In the breeding experiment of the eel larva containing the krill degradation product described in Patent Document 2, the feed using whole egg powder, which is easily available instead of the shark egg powder, Inferior growth has been observed up to 28 days of age.

  The present inventors have developed a feed in which a specific ratio of chicken eggs and skim milk powder that do not use natural resources such as a horseshoe shark egg, and have confirmed that eel larvae can be raised up to 100 days of age (Patent Document 3). .

  The present inventors further searched for a low-cost feed that can be stably supplied in the future, including natural resources, and decomposed fish-derived protein (hereinafter also referred to as “FPH”) and frozen small crust. A feed containing potatoes was developed and it was confirmed that eel larvae could be raised up to 60 days of age (Non-Patent Document 1), but the growth rate and survival rate did not reach that of shark egg feed.

JP-A-11-253111 JP-A-2005-13116 Japanese Patent Application No. 2015-22456

Fish Sci (2013) 79 p.681-688

  The present invention solves the conventional problems, can be prepared from materials considered to be stable supply, without depending on materials that are becoming difficult to obtain such as shark eggs, and moreover, the larvae after hatching can be efficiently produced It aims at providing the feed which can be grown, and its manufacturing method.

  The present inventors made a prototype of a new feed mainly composed of animal protein such as FPH and raw shirasu, and conducted a breeding test of eel larvae. As a result, it was confirmed that the animal protein in the feed was further absorbed by degrading enzymes contained in the raw shirasu and the protein was more easily absorbed, and it was confirmed that artificially hatched eel larvae could be reared up to the shirasu eel. It came.

That is, the embodiment of the present invention is as follows.
[1] A feed for larvae containing a fish protein degradation product and raw shirasu
[2] A part of the raw shirasu is replaced with small crustaceans. [1] Feed for larvae.
[3] The larvae feed according to [1] or [2], wherein the larvae are eel larvae.
[4] A method for producing a feed for larvae, comprising mixing a raw shirasu with a proteolytic product of fish meat and decomposing the proteolytic product of fish meat with an enzyme of the raw shirasu.
[5] The method for producing a feed for larvae according to [4], wherein a part of the raw shirasu is replaced with a small crustacean.
[6] The method for producing a feed for larvae according to [4] or [5], wherein the larvae are eel larvae.

  The “fish meat protein degradation product” used in the present invention is a degradation product treated with a degrading enzyme using an inedible portion (internal organs, bones, etc.) generated in a fish simple substance and a food processing process as a raw material, and FPH (Fish What is marketed as protein hydrolysate) can be used.

  The “raw shirasu” used in the present invention is mainly anchovy larvae and is a natural resource, but it is landed about 60,000 tons per year only on the coast of Japan, and a sufficient amount can be secured for raising eel larvae. It is.

  “Small crustaceans” that replace part of the raw shirasu are mysids such as horned krill, and those that are frozen raw are widely used as feed for aquaculture of fish. Is also marketed under the name "Ami shrimp".

Digestion does not proceed with the fish protein degradation product as it is, but digestion proceeds when a self-digestible material such as raw shirasu or small crustaceans is added.
In addition, since the rate of digestion depends on temperature, in order to efficiently proceed with digestion, it is preferable to add raw shirasu or the like to fish meat protein and then hold at about 50 ° C. for about 3 hours.

  The feed for eel larvae of the present invention can be produced with a stable quality material without using natural resources such as shark eggs, which are uneasy for stable availability, and trial production of a feed with easily available materials is also performed. It has the advantage that it is easy to do.

For the purpose of improving the performance of FPH-based feed for eel larvae, a feed containing raw shirasu and small crustaceans was prepared and the feed performance was compared.
The composition (weight ratio) of each feed is as shown in Table 1.

注１）CPSP specialG（フランス Soprepeche社製）
注２）三陸産「アミエビ」
注３）エマリードP（栄研商事社製）
注４）フィッシュエードＣ（インターベット社製）
注５）ケルプ1（(株)キミカ社製）

Note 1) CPSP specialG (manufactured by Soprepeche, France)
Note 2) Sanriku “Ami shrimp”
Note 3) Emerald P (manufactured by Eiken Shoji Co., Ltd.)
Note 4) Fishade C (manufactured by Interbed)
Note 5) Kelp 1 (Kimika Co., Ltd.)

<Experiment 1>
For FPH, feed 1 containing small crustaceans and feed 2 containing small crustaceans and fresh shirasu were prepared, and a peristaltic 6.5 L peanut-type aquarium (see Japanese Patent Application Laid-Open No. 2014-177332) was used for each feed. Three tanks were used for each, and 250 fishes of 5-day-old eels were accommodated per aquarium, and feeding was performed 5 times a day for 2 to 3.5 mL for 15 minutes. In addition, the water injection to each water tank was 0.6 L / min. Other rearing conditions are as described in JP 2014-177332 A.

  When the eel larvae were housed in each aquarium and at the age of 20 days, 20 fish were randomly extracted from each aquarium and anesthetized with phenoxyethanol, and then the total length and height of the eel larvae were measured. The results are shown in Table 2.

  From the results in Table 2, it is clear that the eel larvae fed with feed 2 containing small crustaceans and raw shirasu are fuller and longer than the eel larvae fed only small crustaceans without raw shirasu. Body height was significantly higher.

<Experiment 2>
For FPH, feed 4 containing raw shirasu and feed 3 containing small crustaceans and raw shirasu were prepared, and eel larvae were reared in the same manner as in Experiment 1.
In addition, for confirmation of the feed amount and residual amount of the feed of Experiment 1, squid powder was added as a colorant, but in fact, the feed of the present invention could be confirmed visually without being colored, In this experiment, seaweed powder conventionally used in eel larvae feed was used as a raw material for vitamin preparations instead of squid powder, and a small amount of soybean lecithin was also added.
As shown in Table 2, there was no significant difference between the two at 20 days of age. This result suggests that raw shirasu influences eel larvae growth more strongly than small crustaceans.

In Experiment 1, the growth of eel larvae was excellent, and an experiment was conducted in which eel larvae were reared to glass eels using a feed containing raw shirasu and small crustaceans.
Table 3 shows the composition (weight ratio) of the feed used in the experiment. The feed 5 is the same as the feed 3 used in Experiment 2 of Example 1, and the feed 6 is obtained by adding a small amount of soybean peptide conventionally used for eel larvae feed. The experimental method is the same as in Example 1.

注１）CPSP specialG（フランス Soprepeche社製）
注２）三陸産「アミエビ」
注３）エマリードP（栄研商事社製）
注４）フィッシュエードＣ（インターベット社製）
注５）ケルプ1（(株)キミカ社製）
注６）ハイニュートＨＫ（不二製油社製）

Note 1) CPSP specialG (manufactured by Soprepeche, France)
Note 2) Sanriku “Ami shrimp”
Note 3) Emerald P (manufactured by Eiken Shoji Co., Ltd.)
Note 4) Fishade C (manufactured by Interbed)
Note 5) Kelp 1 (Kimika Co., Ltd.)
Note 6) High New HK (Fuji Oil Co., Ltd.)

  Table 4 shows the results of breeding experiments using the above feed 5 and feed 6.

  As is clear from the experimental results in Table 4, it was confirmed that eel larvae, which are artificial seedlings, can be raised to white eel even with feed that can be stably obtained without using shark eggs. .

  According to the present invention, eel larvae are bred by feed using materials that are cheaply and stably available in the market without using raw materials such as shark eggs that are difficult to obtain stably. It can be transformed into glass eels, expanding the possibility of mass production of glass eels.

Claims (4)

Feed for eel larvae containing fish meat protein digest and raw shirasu. The eel larvae feed according to claim 1, wherein a part of the raw shirasu is replaced with a small crustacean. A method for producing a feed for eel larvae, characterized in that raw shirasu is blended with a fish protein hydrolyzate, and the fish protein hydrolyzate is decomposed by an enzyme of the raw shirasu. The method for producing a feed for eel larvae according to claim 3, wherein a part of the raw shirasu is replaced with a small crustacean.