DESCRIPTION

A FEED COMPOSITION FOR CULTURING FISHES AND SHELLFISHES Technical Field

The present invention relates to a feed composition for culturing fishes and shellfishes. More particularly, it relates to a feed composition prepared by having a known artificial synthetic feed contain at least one of dipeptide and tripeptide composed of amino acids selected from the group consisting of glycine, alanine, valine, methionine, serine and asparagine.

Background Art Marine culturing has recently performed a remarkable improvement. Whether fresh water or seawater, fry of various species have successfully been bred, and the number of successful breedings has been increasing year by year. With the advance of breeding and culturing, development of artificial synthetic feeds suitable for breeding and culturing fishes and shellfishes has been made, and artificial synthetic feeds for culturing red sea beam, flatfish, sweetfish and Kurama prawn have already been put to practical use. However, at present time, known artificial synthetic feeds have many problems in light of the nutritional science for fishes. Vitality of fry grown by feeding these feeds is low, and survival rate as well as growth rate of the fry is low. These feeds are not satisfactory for mass production of cultured fishes and shellfishes. As the source of known artificial synthetic feeds, fish meal, casein, squid meal and other animal materials as well as soybean oil meal, wheat flour, α-starch, yeasts for feeds and other vegetable materials are used. ^• Also, animal oils and fats, vegetable oils and fats, vitamins, minerals and antioxidizing agents are also used. Further, depending on the 7

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species of cultured fishes and shellfishes, amino acids such as alanine, glycine, methionine, threonine, tryptophan, lysine, glutamic acid, isoleucine and arginine are supplemented.

The fry grown on artificial synthetic feeds made of these materials do not have a satisfactory vitality and a satisfactory survival rate, and grow slowly. Therefore, the improvement on known artificial synthetic feeds has been desired.

Disclosure of Invention

According to the present invention, there is provided an artificial synthetic feed containing at least one of dipeptide and tripeptide composed of amino acids selected from the group consisting of glycine, alanine, valine, methionine, serine and asparagine. The artificial synthetic feed of the present invention is fed to fry and cultured fishes to thereby enhance their vitality, raise their survival rate and promote their growth. Any dipeptide and tripeptide composed of the amino acids selected from the group consisting of glycine, alanine, valine, methionine, serine and asparagine may be used in the present invention so long as they can enhance vitality, raise survival rate and promote growth, of fry and cultured fishes. More preferably, a dipeptide or tripeptide wherein the amino acid residue at the N-terminal is selected from the group consisting of alanine, glycine and methionine and the remaining amino acid(s) is/are selected from the group consisting of glycine, alanine, valine, methionine, serine and asparagine, can be used. With each of the amino acids constituting the dipeptide and tripeptide, optical isomers of L-type and DL-type can be used. Specifically, the dipeptide includes, for example, glycyl-DL-alanine, glycyl-DL-valine, DL-alanyl-DL-methionine, DL-alanyl-DL-serine, DL-alanyl-L- asparagine and L-methionyl-glycine. The tripeptide includes. for example, glycyl-glycyl-glycine and DL-alanyl-glycyl- glycine. The dipeptide and tripeptide are used alone or in combination.

The feed composition of the present invention comprising the above-described dipeptide and tripeptide and the artificial synthetic feed can be prepared by adding the dipeptide and tripeptide to the artificial synthetic feed and mixing the two components. Alternatively, the dipeptide and tripeptide are mixed with some of powdered artificial synthetic feed materials, and the mixture is added to the other materials for the artificial synthetic feed. Further, mixing is carried out to thereby prepare the feed composition of the present invention.

The amount of the dipeptide and tripeptide to be contained in the artificial synthetic feed is arbitrary.

However, the dipeptide and tripeptide is preferably used in an amount of 0.1 to 5% by weight based on the artificial synthetic feed.

As the source of the artificial synthetic feed, the animal materials such as fish meal, casein and squid meal, the vegetable materials such as soybean oil meal, wheat flour, α- starch and yeasts for feeds, animal oils and fats, vegetable oils and fats, vitamins, minerals, amino acids and antioxidizing agents are mentioned. A second object of the present invention is to provide a method for culturing fishes and shellfishes, which comprises culturing fishes and shellfishes in a conventional manner while dipping the fishes and shellfishes in water containing at least one of the above-mentioned dipeptide and tripeptide in the stage of fry and/or juvenile. The water mentioned herein includes, for example, fresh water, seawater and brackish water. The concentration of the dipeptide and tripeptide, the temperature of the water, the dipping time, etc. depend on species of the fishes and shellfishes. Generally, the concentration of the dipeptide and tripeptide in the water varies from 0.01 up to 100 ppm. The temperature of the water is in the range of from 8 to 30°C and preferably adjusted to the optimum temperature for species of the fishes and shellfishes to be cultured. The dipping time is in the range of from 5 minutes to 2 days. Thus, the dipeptide and tripeptide can be effectively introduced into fish and shellfish bodies.

The fishes to which the present invention is applicable include, for example, red sea bream, striped beak- perch, bastard halibut, flatfish, yellowtail, striped jack, sweet fish, salmon, Kuruma prawn and swimming crab.

Best Mode for Carrying Out the Invention

Certain specific embodiments of the invention are illustrated by the following representative examples. Example 1

As the artificial synthetic feed, 57.5 g of casein, 3 g of a 1:1:1 amino acid mixture of threonine, leucine and isoleucine, 5 g of dextrin, 5 g of α-starch, 6 g of a mineral mixture (McCollum salt) , 6 g of a vitamin mixture followed by Halver, 4 g of fish-liver oil, 5 g of soybean-lecithin and 2 g of vital gluten were mixed together. Then, 0.5 g of glycyl- DL-alanine, glycyl-DL-valine, glycyl-glycyl-glycine, DL- alanyl-glycyl-glycine, DL-alanyl-DL-methionine, DL-alanyl-DL- serine, DL-alanyl-L-asparagine or L-methionyl-glycine was added thereto with stirring. To the mixture was added 6 g of zein with stirring. Further, 150 ml of 60% ethanol aqueous solution was added thereto. Stirring was carried out at 15,000 rpm for 3 minutes, and the mixture was lyophilized to prepare 8 varieties of the feed composition of the present invention.

Example 2

As the artificial synthetic feed, 53.5 g of squid meal, 2 g of a 1:1 amino acid mixture of arginine and methionine, 19 g of yeast for feed, 3 g of α-starch, 8 g of a mineral mixture (McCollum salt) , 6 g of a vitamin mixture followed by Halver, 4 g of fish-liver oil, 3 g of soybean- lecithin and 2 g of vital gluten were mixed together. - Then, 0.5 g of glycyl-DL-alanine, glycyl-DL-valine, glycyl-glycyl- glycine, DL-alanyl-glycyl-glycine, DL-alanyl-DL-methionine, DL-alanyl-DL-serine, DL-alanyl-L-asparagine or L-methionyl- glycine was added thereto with stirring. Further, 30 mi of water was added, and kneading and molding were carried out with extruder (product of Wenger) for one minute. The molded product was air-dried to prepare 8 varieties of the feed composition of the present invention.

Experimental Example 1 Each of 11 groups of red sea bream fry, each group consisting of 20 individuals, was put into a water in a 100 l- tank, and cultured for 30 days. During the culturing, the feed composition prepared in Example 1 was fed up twice a day, in the morning and the afternoon. As the control, the same culturing and feeding were carried out except that (A) the artificial synthetic feed of Example 1 containing no dipeptide and tripeptide, (B) the feed composition comprising the artificial synthetic feed of Example 1 and a 1:1 mixture of alanine and glycine or (C) the feed composition comprising the artificial synthetic feed of Example 1 and a 1:1:1:1:1 amino acid mixture of alanine, glycine, valine, methionine and serine was used in place of the feed composition prepared in Example 1.

The results of the culturing are shown in Table 1. Table 1

Average weight Weⁱght- _{Survival (}g₎ increase _rafce ____ rate

Start 30 days (%) (%)

(Control)

(A) (B) (C)

(The present invention)

Glycyl-DL-alanine

Glycyl-DL-valine Gylcyl-glycyl-glycine

DL-alanyl-glycyl-glycine DL-alanyl-DL-methionine DL-alanyl-DL-serine DL-alanyl-L-asparagine L-methionyl-glycine

Experimental Example 2

The same culturing and feeding was carried out except that flatfish fry were used in place of red sea bream fry.

The results of the culturing are shown in Table 2. Table 2

Average weight Weight- Survival increase (9) rate rate

Start 30 days (%) (%)

(Control)

(A) (B) (C)

(The present invention)

Glycyl-DL-alanine

Glycyl-DL-valine Glycyl-glycyl-glycine

DL-alanyl-glycyl-glycine DL-alanyl-DL-methionine DL-alanyl-DL-serine DL-alanyl-L-asparagine L-methionyl-glycine

Experimental Example 3

Each of 7 groups of striped beak-perch fry, each group consisting of 20 individuals, was put into a water in a 100 Jl-tank, and cultured for 30 days. During the culturing, 4 varieties given in Table 3 were selected out of the feed composition prepared in Example 1 and fed up twice a day, in the morning and the afternoon. As the control, the same culturing and feeding were carried out except that (A) the artificial synthetic feed of Example 1 containing no dipeptide and tripeptide, (B) the feed composition comprising the artificial synthetic feed of Example.1 and a 1:1 amino acid mixture of alanine and glycine or (C) the feed composition comprising the artificial synthetic feed of Example 1 and a 1:1:1:1:1 amino acid mixture of alanine, glycine, valine, methionine and serine was used in place of the composition given in Table 3.

The results of the culturing are shown in Table 3,

Table 3

Average weight Weight- _Survival increase _rafce

(q.

Start 30 days (%) (%)

(Control)

(A) (B) (C)

(The present invention)

Glycyl-DL-valine

DL-alanyl-glycyl-glycine

DL-alanyl-DL-methionine

DL-alanyl-DL-serine

Experimental Example 4 Each of 11 groups of Kuruma prawn larvae, each group consisting of 100 individuals, was put into a water in a 40£- double bottom tank, and cultured for 30 days. During the culturing, the feed composition prepared in Example 2, and amounting to 4-5% of the total weight of the larvae was fed once a day, in the evening. In the next morning, a leftover feed composition, if any, was removed by siphon. As the control, the same culturing and feeding were carried out except that (A) the artificial synthetic feed of Example 2 containing no dipeptide and tripeptide, (B) the feed composition comprising the artificial synthetic feed of Example 2 and a 1:1 mixture of alanine and glycine or (c) the feed composition comprising the artificial synthetic feed of Example 2 and a 1:1:1:1:1 amino acid mixture of alanine, glycine, valine, methionine and serine was used in place of the feed composition prepared in Example 2.

The results of the culturing are shown in Table 4.

Table 4

Average weight Weight- Survival increase _rate (3} rate

Start 30 days (%) (%)

(Control)

(A) (B) (C)

(The present invention) Glycyl-DL-alanine Glycyl-DL-valine Glycyl-glycyl-glycine DL-alanyl-glycyl-glycine DL-alanyl-DL-methionine DL-alanyl-DL-serine

DL-alanyl-L-asparagine L-methionyl-glycine