JPH04200375A - Production of new feed for culturing fish - Google Patents

Abstract

PURPOSE:To obtain a feed for culturing fishes capable of adding a large amount of fats and oils to a stable feed by using a specific twin-screw extruder in which a structure of the screw tips and die part is changed and granulating a prescribed assorted feed. CONSTITUTION:A powdery feed of the type in which a large amount of fats and oils is added without using a live bait is granulated by using a water-soluble binder and/or a thermoplastic emulsifying agent. In the process, the following twin-screw extruder is used. That is the aforementioned twin-screw extruder is prepared by removing conical parts at the screw tips and providing scraping parts of the same diameter as that of screws 1. The above-mentioned scraping parts are designed to house scraping blade installing parts 2 and scraping blades 4. Thereby, since a gap is formed around the scraping blades just before passing a kneaded material through a die hole 6, the material fed until the pressure required for its passage through the die is kept constant is stocked in the gap.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing fish feed. For more details,
This invention relates to a method for producing fish feed that is excellent in improving fish predation rates and preventing self-contamination caused by feeding.

[Conventional technology and its problems]

In recent years, fishing grounds in Japan have been significantly narrowed due to international restrictions such as the establishment of economic zones. For this reason, Thailand
Sea-based fish farming, such as yellowtail, flounder, horse mackerel, puffer fish, and coho salmon, is becoming popular. However, currently, as feed for marine aquaculture, sardines, mackerel, saury, shrimp, etc., which are commonly caught fish, are minced, cut, or administered as is, resulting in a large amount of water-soluble nutritional components being leached out. Mince etc. are often dissipated in the water, so the predation rate of fish is low.

In addition, recently, fishmeal, oil cake, grains, sugars, nutrients (vitamins, minerals), and other fish feed ingredients (referred to as moist pellets or Oregon pellets) have rapidly become popular, but There are various methods, and molded feed pellets tend to crumble when applied to the sea surface, causing the feed to scatter.Furthermore, since the feed pellets are not floatable, the feed pellets that are not eaten by the fish sink and contaminate the aquaculture sea surface, so self-contamination is prevented. is also at its limit.

In addition, among marine fish such as yellowtail, sea bream, and flounder, there are solid pellets called hard pellets, which are often used as feed for sea bream and inland aquaculture. When administered to the water surface, it disintegrates and dissipates in a very short time, which has the disadvantage of lowering the rate of fish predation. This is made by compression molding a blended feed in powder form, and it is not possible to add a binder or the amount of fat necessary for the fish, so raw feed or moist pellets are often fed separately. As a result, feeding causes self-contamination, and the situation is such that it cannot be expected to be effective in preventing marine pollution.

In addition, sodium carboxymethyl cellulose (hereinafter abbreviated as C?IC) is used as a binder for moist pellets.
The use of water-soluble polymers such as sodium alginate is described in Japanese Patent Publication No. 41-13773.

However, moist pellets using these water-soluble polymers have low caking strength and seawater resistance, and when placed in seawater, they swell in a short time, reduce their caking strength, and disintegrate. Therefore, due to the outflow caused by the feeding of fish, there is a significant loss of food outside the cage, resulting in a decrease in the predation rate of fish and contamination of fishing grounds, which is not desirable.

Furthermore, moist pellets are not hard enough, so the cut ends tend to crumble, resulting in powdering, which is undesirable. Furthermore, when they are stored in a feeding box during production, they deform due to their own weight and become lump-like, making feeding operations difficult. becomes. In addition, during granulation, a satisfactory product cannot be obtained unless the ingredients are thoroughly mixed and mixed, and by adding a binder, water absorption is increased and hardness is obtained, but it is not stable over time. It lacks elasticity and tends to soften and crumble in a short period of time.

Recently, - When feeding pellets after temporary freezing and then re-thawing, as is done in boat fishing, or when pellets have been granulated for a long time, the pellets soften considerably, and in the worst case, it is difficult to cast the pellets. It is often impossible to do so.

Further, although hard pellets can be cast well, they have nutritional deficiencies, high disintegration in water, and easy dissipation.

In addition, using a single-screw extruder used in the production of pet food, etc., we manufacture expansion products (pressurized and heated molded products called EP) that add starch, gluten, etc. However, it is not possible to add oil or fat during molding, and the oil must be absorbed into the molded pellets before feeding, and because they are exbanding type pellets, they float on the sea surface when fed, resulting in a large amount of spillage outside the cage. Furthermore, since the post-adsorbed oils and fats are not kneaded into the pellets, they tend to separate from the pellets and seriously pollute the sea surface.

There have been various studies on the use of twin-screw extruders in producing fish feed, but when using the current twin-screw extruders for food molding and plastic molding, the pressurized molding part (die or In the gap between the screw tip (called a nozzle) and the tip of the screw, the material with increased lubricity softens violently due to friction, and in extreme cases it becomes liquid and does not pass through the molding part.

FIG. 3 is a schematic partial cross-sectional view showing an example of a die plate portion of a conventional biaxial extruder.

The material fed to the gap 9 between the die 3 and the tip of the screw 1 generates heat due to friction with the tip of the screw, and the material tends to soften. The softened material becomes difficult to transmit extrusion pressure, generates more heat, and becomes liquefied. This phenomenon is remarkable in the case of fish feed materials, and it is difficult to mold fish feed materials using a conventional twin-screw extruder as shown in the figure.

In addition, some conventional biaxial extruders have a conical tip with the leading edge as the apex, and the molding part is also cut into a conical shape, and the molding hole in this molding part is the part that is most compressed. However, in the case of producing fish feed, it is necessary to add water and knead in order to give the material cohesive strength by pregelatinizing the material and to perform other functions of the binder normally used for fish farming. Add water. In addition, despite the twin screws, the molding part (nozzle) is single, so
High nozzle pressure is required. However, as mentioned above, since fish feed materials soften due to friction, extrusion pressure cannot be obtained and the kneaded materials cannot pass through the nozzle. Therefore, heat generation due to friction increases, and in extreme cases, the feed material becomes liquid and cannot be molded.

In addition, the currently required flexible pellets containing a large amount of oil and fat require the addition of 15% by weight or more of oil and fat, but with conventional twin-screw extruders, the limit of adding oil and fat is 6% by weight; When adding , it is difficult to obtain molded pellets with the hardness and cohesive strength required for practical use.

Furthermore, even if the amount of oil added is 6% by weight or less and molded pellets for practical use can be formed, the capacity of the equipment will be extremely reduced and it will not be suitable for factory production, and the operation will be quite unstable during manufacturing. This is not desirable.

[Means for Solving the Problems] As a result of intensive research to solve the above-mentioned problems, the present inventors found that when producing compound feed to which a water-soluble binder or starch is added, the tip of the screw and the die are We have discovered that by using a twin-screw extruder with a modified part structure, it is possible to produce soft and good quality pellets for fish farming in a factory, and have completed the present invention.

That is, the present invention provides a method for granulating a powdered feed with a large amount of oil and fat added for fish farming that does not use live feed using a water-soluble binder and/or a thermoplastic emulsifier, except for the conical part at the tip of the screw. This uses a twin-screw extruder that includes a screw equipped with a scraping blade of the same diameter that rotates coaxially with the screw, and a die equipped with a die hole that has a recess that can accommodate the scraping blade at the tip of the screw. The present invention provides a method for producing fish feed, which is characterized by granulating the feed.

The present invention uses an improved structure of the screw tip and die of a twin-screw extruder.
It is a type that adds a large amount of oil and fat, which is difficult to do with conventional twin-screw extruders, and it molds fish feed raw materials that do not use live bait to obtain pellets that are flexible and difficult to disintegrate.

That is, by using the twin-screw extruder with the improved structure of the present invention, liquefaction of the material due to friction is prevented, and the processed feed is always passed through the molding section (die) under a constant pressure, resulting in stable feed. This makes it possible to add large amounts of oil and fat.

Hereinafter, the present invention will be explained based on the drawings.

An example of a two-screw extruder according to the present invention is shown in FIG. In FIG. 1, 1 is a screw, 2 is a scraping blade attachment part, 3 is a die, 4 is a scraping blade, 5 is a cutter, 6 is a die hole, 7 is a cylinder, and 8 is a die attachment plate.

The two-screw extruder according to the present invention has a scraping part having the same diameter as the screw 1, except for the conical part at the tip of the screw. This scraping part is the scraping blade attachment part 2.
and a scraping blade 4. Moreover, the molding part (die part) 3 is also structured to have a recess corresponding to the screw, and the scraping blade 4 is accommodated in this recess. By doing this, a gap is created around the scraping blade just before the cross-conducting material passes through the die hole 6, so the fed material is stored in this gap until the pressure required for passing through the die becomes constant. (Hereinafter, this void may also be referred to as a stock hole). Therefore, there is no heat generation due to friction, and no softening of the material occurs. In addition, the cross-wire material filled in this gap is scraped off by the cutter 5 at right angles to the extrusion direction immediately after passing through the die hole 6, so that even more uniformity can be achieved. As described above, according to the present invention, good molded pellets having constant hardness can always be obtained. When such an improved twin-screw extruder is used, there is no extrusion caused by friction, so more added water or oil can be used, and the molding part (die) is placed in front of each screw. Since it will be installed, manufacturing capacity will also be improved.

The improved twin-screw extruder machine used in the present invention makes it possible to add a large amount of oil and fat, which was previously considered extremely difficult, and also makes it possible to reduce the amount of water added by adding oil, resulting in molded pellets with a high moisture content. In this case, it also has the effect of suppressing water activity and has the effect of increasing mold and rot resistance.

Conventionally, moist pellets (a combination of minced raw feed and compounded feed) are provided by local manufacturing at the farm, so the type of raw feed or the ratio of raw feed used differs at each farm, making it difficult to obtain feed of a constant quality. The drawback is that it does not yield pellets, and the taste and meat quality of the cultured fish that are raised are also significantly different. In addition, each aquaculture farmer must install the equipment, which imposes a large cost burden. In addition, moist pellets have a high water content, so they have extremely low shelf life and are difficult to handle when feeding.

Dried pellets for freshwater fish are manufactured using a CPM type (California Pellet Mill) molding machine, but due to the low moisture content (supplied by steam), strong mechanical pressure is required, and water-soluble viscosity Addition of binders or liquid fats and oils is difficult.

This method does not provide molded pellets with the flexibility required by marine fish, especially non-omnivorous fish such as flounder, yellowtail, and pufferfish. Furthermore, when feeding, this type of molded pellet absorbs water and disintegrates in a very short time and dissipates, so it is not expected to be effective in preventing sea surface pollution.

A feature of the present invention is that it is possible to produce flexible molded pellets by using a high-protein compound feed and simultaneously supplying a small amount of water and a large amount of oil to the compound feed to a granulator. This can be mentioned.

The thermoplastic emulsifier used in the present invention includes those that are approved as food additives and feed additives, are solid at room temperature, and have a relatively low melting point. For example, the product name "Leodore TW-8120""Leodore T
Examples include polyoxyethylene sorbitan fatty acid esters such as Shin-5320J. In addition, the product name “Leodore M
Examples include glycerin fatty acid esters such as S-50J and Rheodol MS-60J, and sucrose fatty acid esters.

In the present invention, ordinary ingredients can be used as fish feed raw materials. Fishmeal is used as fish feed, and can be roughly divided into two types: white finsch meal and brown finsch meal, and is a typical source of animal protein.

Other suitable animal proteins include meat meal, bone meal, feather meal, blood meal, skim milk powder, Antarctic krill meal, and squid meal.

Further, as the vegetable protein, oil cake, grain, bran, soybean meal or soybean flour, starch, gluten meal, etc. are used.

Vitamins include vitamin B2, vitamin B2, vitamin B&, vitamin B1□, vitamin C, niacin,
Inositol, para-aminobenzoic acid, etc. are used, and minerals such as phosphorus, calcium, potassium, and sodium are added as necessary.

Since the feeding status of feed differs depending on the species of fish, it is necessary to have equipment that can easily adjust the physical properties (specific gravity, sedimentation rate, flexibility, etc.) of the molded pellets, and the improved twin-screw extruder according to the present invention can be used. This is achieved by In addition, there is no need to use expensive solid fats for the fat bones, which are a source of calories, and there is no need to use commonly used feed oil (
(cod liver oil, sardine oil, etc.) is sufficient, and by adding 6 to 30% by weight to the compounded feed, fish pellets that are soft and have good shape retention in water can be obtained.

〔Effect of the invention〕

In the present invention, by using an improved twin-screw extruder, it is possible to add any amount of water and oil, which prevents material liquefaction due to friction and equalizes the pressure in the stock hole. By doing this, it is possible to obtain a well-formed pellet that is always of constant quality, flexible and does not crumble.

In addition, since the die part is installed at the front of each screw,
Manufacturing capacity will also improve. For example, since the specific gravity of the pellet can be adjusted depending on the purpose, it is possible to produce feed that is good for slow-feeding draft fish or flounder.

Even when the pellets produced according to the present invention are administered into the sea for feeding, they have good shape retention and do not easily collapse, so water-soluble nutrients do not elute into the water, and contamination of the seawater can be prevented. In addition, the pellets produced according to the present invention do not crumble easily and can be prevented from leaking out of the cage, and the specific gravity can be adjusted to any desired value by setting the temperature of the barrel, increasing the fish predation rate and improving feed efficiency. It is also effective in preventing environmental deterioration of fishing grounds due to sinking of lost bait. It also enables automatic feeding in unmanned offshore aquaculture.

[Examples] The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 and Comparative Example 1.2 To the basic test feed shown below, 1% by weight of CMC (CMC Daicel <2260>) from Daicel Chemical Industries ■ and 6% by weight of potato starch were post-mixed as a binder. Using the improved twin-screw extruder according to the invention or a conventional single-screw or twin-screw extruder, the amounts of water and oil shown in Table 1 were added and granulated to obtain feed pellets.

The conditions at the time of extrusion and the condition of the molded product were evaluated, and the results are shown in Tables 1-1.

Evaluation of the state during extrusion is as follows.

◎; Best ○; Good Δ; Bad ×; Very bad Bashinli Basic Fish Meal (Brown Meal) 80.0 Gluten Meal 2.1 Flour
10.6 Alf Alf Aamir 1.
5 Soybean meal 2.1 Brewer's yeast
1.6 liver powder
0.7 Calcium phosphate 0.7 Nutrients (vitamins, minerals) 0.7 100.0% by weight Table 1 Note) Weight% relative to ml basic feed Examples 2 to 4 and Comparative Examples 3 to 5 Example 1 Daicel Chemical Industries ■'s CMC (CMC Daicel <1330>) was added to the same basic feed for the test as a binder.
1% or 3% by weight and 6% by weight of potato starch were post-mixed, and the improved twin-screw extruder according to the present invention or a normal twin-screw extruder having both a die and a nozzle diameter of 9IllII+ was used as shown in Table 2. A certain amount of water and oil were added and granulated to obtain feed pellets.

The conditions at the time of extrusion and the condition of the molded product were evaluated in the same manner as in Example 1, and the results are shown in Table 2.

Examples 5 to 7 and Comparative Examples 6 to 8 CMC from Daicel Chemical Industries (CMC Daicel <1880>
) 2% by weight, post-mixed with 6% or 10% by weight of potato starch, and using an improved twin-screw extruder according to the present invention or a conventional twin-screw extruder, add water and the amount shown in Table 3. Oil was added and granulated to obtain feed pellets.

The conditions at the time of extrusion and the condition of the molded product were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Fish meal (brown meal) 92.0 Gluten meal O Alfalfa meal 2.3 Brewer's yeast
1.6 liver powder
0.7 Calcium phosphate 0.7 Nutrients (vitamins, minerals) 0.7 Potato starch 6.0 CMC (CMC
Daicel <1880>) 2. O Fish meal (brown meal) 88.0 Gluten meal
4.0 Alfalfa meal 2.
3 Brewer's yeast 1.6 Liver powder
0.7 Calcium phosphate
0.7 Nutrients (vitamins, minerals) 0.7 Potato starch 6.0 CMC (CMC
Daicel <1880>) 2. O Fish meal (brown meal) 82.0 Gluten meal
O Alfalfa meal 2.3 Brewer's yeast
1.6 liver powder
0.7 Calcium phosphate 0.7
Nutrients (vitamins, minerals) 0.7 Potato starch 10.0100.0% by weight

[Brief explanation of the drawing]

Fig. 1 is a schematic overhead cross-sectional view of the advanced end of the improved screw and the improved die of the twin-screw extruder according to the present invention;
Figure (a) is a schematic partial cross-sectional view of the advanced end of the improved screw and the improved die, (b) is a front view, (C) is a schematic side cross-sectional view, and Figure 3 is a die of a conventional twin-screw extruder. It is a partial cross-sectional schematic diagram of a plate part. 1... Screw 2... Scraping blade attachment part 3... Die 4... Scraping blade 5... Cutter 6... Die hole 7... Cylinder 8... Die mounting plate 9 ...Vacancy applicant Kaoru Furuya (3 others) Figure 1 Mc2 Figure 3

Claims (1)

[Claims] 1. When granulating a powdered feed with a large amount of oil and fat added for fish farming that does not use live feed using a water-soluble binder and/or a thermoplastic emulsifier, the screw and Granulation using a twin-screw extruder that includes a coaxially rotating screw equipped with a scraping blade of the same diameter and a die equipped with a die hole having a recess capable of accommodating the scraping blade at the tip of the screw. A method for producing feed for fish farming, characterized by: