JPS5963146A - Feed for cultivation of fish and shellfish - Google Patents

Abstract

PURPOSE:To obtain a feed useful for the cultivation of fish and shellfish, by encapsulating microbial algae with a hydrophilic polymer, and proliferating the algae under light irradiation. CONSTITUTION:Microbial algae (e.g. Anabaena flos-aquae, Nostoc muscorum, etc.) is dispersed in an aqueous solution of a hydrophilic polymer (e.g. 0.1-5% aqueous solution of sodium alginate), and the obtained dispersion is added dropwise or sprayed to an aqueous solution for gelation (e.g. 1-10% aqueous solution of calcium chloride) to coat the microbial algae with the hydrophilic polymer. The encapsulated algae is cultured and proliferated in sea water under light irradiation, and collected to obtain an encapsulated edible feed for the cultivation of fish and shellfish.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new feed for cultivating fish, crustaceans, and shellfish (hereinafter referred to as fish and shellfish), which comprehensively encapsulates microalgae such as blue-green algae and green algae.

Conventionally, when cultivating fish and shellfish, zooplankton were first cultivated and the dough was used as feed for the fish and shellfish. Even in nature, a food chain exists in which microalgae are eaten by zooplankton, and zooplankton are eaten by fish and shellfish, and the utilization efficiency at each stage is estimated to be about 10%.

It is easily understood that if one stage of the food chain could be omitted and fish and shellfish could directly utilize fine gravel, an extremely efficient food production process could be provided. It's probably somewhere.

From a nutritional standpoint, it is already known that freshwater blue-green algae can be used as feed for milkfish, carp, tilapia, etc. On the other hand, certain marine blue-green algae can also be useful feed for tilapia, etc. has recently been revealed (A.

Mitsui et al., Manuscript
for 1nclusion in Proceed
ingsof 1982 conference of
the World Maricultmre 5o
cietyFeb, 28-Mar, 4.1982
).

In particular, the latter can be cultured simply in seawater because it itself has nitrogen-fixing ability, and can be said to have extremely promising potential as feed for fish and shellfish.

However, when microalgae are used as feed according to these prior art techniques, complicated operations such as centrifugation are required for harvesting, and only a portion of the algae can be used as feed because it is dispersed in water after being cast. However, the dry product is relatively hard, has poor eating taste, and lacks the necessary floatability on water, so it is not necessarily suitable for cultivating young fish, etc. difficulties cannot be avoided.

In view of the above, as a result of intensive research, the present inventors have discovered that edible capsule-shaped fodder containing proliferating microalgae is extremely useful as fish and shellfish culture feed, and has thus arrived at the present invention. be.

Hereinafter, the structure, operation, effects, etc. of the present invention will be explained in detail.

As microalgae that can be used in the present invention, An
abaena flos-aquae, hedan-agyQ
n<:jc,a.

Reverse rules [Rinfu plate inspection song 9 clear q manly training for hyunga q use M release button 9M @ 1 Taku 4th printing p Various marine blue-green algae such as jaminosus, M town Kyokarimachi! Gaki aunt-j・q seal-
Her Anal Sister Frog Sakaki: coides, Coelastr
um-probosideum, Selenas
trum sp.

Various freshwater algae such as M. maxima can be exemplified as suitable examples.

Marine blue-green algae such as No. Regarding the conditions, etc., the following documents by Mitsui et al. are referred to.

1) Proceedings of the 3rd
International OceanDevel
opment Conference, 5eino
Printing Co.

Tokyo 3:11-30 (1975) 2) A
bs, Am, Soc, Microbiol, :
128. (1976) 3) Abs, Plant, Phy
siol: 1 06. '(1976-4)
Plant Ph)'5io1.5upp1.61:
17. (1978) 5) Abs, Am, Sa
c, Microbiol: 99. (1978
) + and 6) Proceedings of Bio
-EnerFC7'80, 486-491 (198
0).

Formation of Capsules The microalgae are first dispersed and suspended in an aqueous solution of various parent and aqueous polymers having gel-forming ability, and then brought into contact with an aqueous gelling solution by adding, dropping, injecting, spraying, etc. the aqueous polymer solution. It is encapsulated within the capsule of the "required" method.

Here, as the hydrophilic surface molecule, various natural or synthetic polymers having the ability to form hydrogels can be used, but more preferable are alginic acid, carrageenan, furcellan, agar, etc., seaweed polysaccharides, Examples include plant resin polysaccharides such as gum karaya, gum tragacanth, and gum arabic. In particular, when various seaweed polysaccharides are used as capsule substrates, there are great practical advantages in that they are extremely compatible with microalgae and the capsule substrates themselves are suitable for fish and shellfish feed.

The concentration of polymers such as polysaccharides in these polymer aqueous solutions is appropriately selected within the curve that provides a predetermined capsule wall strength, but is usually about 0.1 to 5%. It is.

On the other hand, when the polymer is alginate, Ca,
Aqueous solutions containing divalent or higher valent metal ions such as Mg and AI (e.g. calcium chloride).

(1 to 10% aqueous solution of magnesium chloride, aluminum sulfate, etc.), or in the case of carrageenan, the aqueous solution to 60 to 80%
Various aqueous solutions that are well-known for the gelation method of each polymer aqueous solution, such as an aqueous solution at room temperature or below that contains or does not contain + ions at °C, and in the case of agar, an aqueous solution that is at a gelling temperature with the aqueous solution as the dissolution temperature. may be selected and used at will.

Feed Form The microalgae-containing capsules provided in this way are then transferred to a step of propagating the encapsulated algae under light irradiation, and proliferation is proceeded until the nutritional value per unit weight reaches a predetermined value.

After the specified growth has been completed, these capsules are collected and dried as they are or at room temperature under reduced pressure, and used as main feed for herbivorous fish and shellfish such as dilapia, carp, milkfish, and canotofish, or used in combination with other feeds to feed trout, trout, etc. It can be used as feed for cultivating a wide variety of fish and shellfish such as sweetfish, eel, red sea bream, yellowtail, kuruma shrimp, abalone rotifer, etc.

Here, fish and shellfish fA of the microalgae-containing capsule-type feed of the present invention
! Some of the characteristics as feed for breeding are summarized as follows.

b) Since the capsule-type feed of the present invention contains gases such as oxygen generated during the algae growth process,
It has water-slag properties even without drying, and is therefore useful as feed for young fish.

On the other hand, in the case of a dried product, the soft capsule body can be restored by easily swelling and absorbing water by underwater feeding, so it has an excellent eating sensation and matches the eating habits of fish and shellfish. In addition, the presence of hydrocolloids such as polysaccharides inside the capsules, which are difficult to undergo gelation, also has the effect of protecting growing algae from damage during vacuum drying.

c) The size of the capsule can be easily and freely changed by changing the diameter of the injection nozzle, etc., so a feed size suitable for the target fish and shellfish can be given without any particular difficulty.

Hereinafter, the present invention will be explained in more detail based on examples.

Example 1 Production of encapsulated feed A seawater suspension of marine blue-green algae No5toc sp (algae concentration 0, 1119 protein/yd) was mixed with the same volume of sodium tyalginate seawater solution, The mixture was injected into a monotonic calcium chloride aqueous solution using a spray gun. The produced encapsulated blue-green algae were collected as soon as possible, cultured with shaking in a seawater tank under light irradiation for 7 days, and encapsulated feed (algae concentration o, s my pr
tein/*/l average capsule particle size 0.5 tone) was obtained.

Cultivation of Fish] J2we encapsulated feed was dried under reduced pressure at room temperature to obtain a dried product with a moisture content of 10%.

Next, feed only this dry product with an average weight of 0.28.1
As a result of raising F. tilapia fry for 5 days, the average weight was 0.
．． Growth of 7222 was observed.

2) As a result of culturing Tirabia fry with an average weight of 0.2569 y for 7 days using only the undried encapsulated feed as feed, the fish grew to an average weight of 0.829 y.

Example 2 Freshwater blue-green algae 5pirulina m.
The procedure was substantially the same as in Example 1, except that the well-known growth conditions for the algae were used [2 and the encapsulated feed (algae concentration 0)]
．． 3W protein/'') was prepared.

This feed, in the form of a semi-dry test product, was found to be particularly useful as a color-promoting feed for fish containing red pigment, such as carp and goldfish.

On the other hand, when carrageenan, agar, etc. were used in place of zitorium alginate as the capsule base material, an encapsulated feed that was approximately equivalent to the former in terms of growth of algae within the capsule and feed suitability was also obtained.

Patent applicant: Nagai Matsu

Claims (2)

[Claims] (1) A fish and shellfish culture feed obtained by contacting an aqueous hydrophilic polymer solution in which microalgae are suspended with an aqueous solution for gelling, enclosing the algae in the capsules, and growing the algae in the capsules under light irradiation. (2) The feed according to claim 1, wherein the hydrophilic polymer aqueous solution is a polymer polysaccharide aqueous solution.