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Claims  |
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What is claimed is:
1. A feed composition for fishes and shellfishes, consisting essentially of
(i) a feed component selected from the group consisting of a synthetic
feed, a semi-natural feed and a wholly natural feed for fish or shellfish
and
(ii) an effective amount of at least one feeding stimulator selected from
the compounds, or salts thereof, represented respectively by the following
formulas (I) to (III):
##STR16##
wherein R.sub.1 and R.sub.2 are the same or different and each represents
a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a mercapto
group, an amino group or an alkyloxy group; X.sup.- represents a
monovalent anion; and an is an integer of 1 to 5;
##STR17##
wherein R.sub.1 and R.sub.2 are each analkyl group having 1 to 5 carbon
atoms, X.sup.- is the same as defined above; R.sub.3 represents a group
selected from the group consisting of an alkyl group having 1 to 2 carbon
atoms, an amino group, a methoxy group and a mercapto group and m.sub.1
and m.sub.2 are each 0 to 2;
##STR18##
wherein R".sub.1 and R".sub.2 are each analkyl group having 1 to 5 carbon
atoms, X.sup.- is the same as defined above, n.sub.1 is zero or 1 and
R.sub.4 is a group selected from the group consisting of an alkyl group
having 1 to 4 carbon atoms, an amino group, an alkyloxy group, an
alkoxycarbonyl group, a mercapto group and a carbamoyl group.
2. A feed composition for fishes and shellfishes, consisting essentially of
(i) a feed component selected form the group consisting of a synthetic
feed, a semi-natural feed and a wholly natural feed for fish or shellfish
and
(ii) an effective amount of at least one feeding stimulator selected from
the compounds, or salts thereof, represented respectively by the following
formulas (I) and (II):
##STR19##
wherein R.sub.1 and r.sub.2 are each an alkyl group having 1 to 5 carbon
atoms, n is 1 to 5 and X.sup.- is a monovalent anion;
##STR20##
wherein R'.sub.1 and R'.sub.2 are each alkyl group having 1 to 5 carbon
atoms, X.sup.- is a monovalent anion, R.sub.3 is a an alkyl group having 1
to 2 carbon atoms and m.sub.1 and m.sub.2 are each 0 to 2.
3. A feeding composition for fishes and shellfishes consisting essentially
of
(i) a feed component selected from the group consisting of a synthetic
feed, a semi-natural feed and a wholly natural feed for fish or shellfish
and
(ii) an effective amount of at least one feed stimulator selected from the
group consisting of dimethyl-.beta.-propiothetin, dimethylthetin,
carboxymethyldiethylsulfonium, carboxymethyldipropylsulfonium,
carboxymethyldibutylsulfonium, carboxymethyldipentylsulfonium,
carboxypropyldimethylsulfonium, carboxybutyldimethylsulfonium,
carboxypentyldimethylsulfonium, carboxymethylmethyldimethylsulfonium,
carboxyethyldiethylsulfonium, carboxyethyldipropylsulfonium,
carboxy-1-methylethyl-dimethylsulfonium,
carboxy-2-methylethyldimethylsulfonium,
carboxy-1-methylpropyldimethylsulfonium,
carboxy-2-methylpropyldimethylsulfonium,
carboxy-3-methylpropyldimethylsulfonium,
carboxy-2-ethylpropyldimethylsulfonium, and salts thereof.
4. The feed composition according to claim 1, wherein R'.sub.1, R'.sub.2,
R".sub.1 and R".sub.2 are an alkyl group having one carbon atoms or a
methoxy group and R.sub.4 is an alkyl group having one or four carbon
atoms.
5. The feed composition according to claim 1, wherein the feed stimulator
is a compound selected from the group consisting of carboxymethysulfonium,
carboxymethyldiaminosulfonium, carboxymethyldimethoxysulfonium,
carboxymethylmethylmercaptosulfonium,
3-carboxy-2-aminopropyldimethylsulfonium,
3-carboxy-2-methoxypropyldimethylsulfonium,
3-carboxy-2-mercaptopropyldimethylsulfonium,
2-trimethylethyldimethylsulfonium, aminomethyldimethylsulfonium,
aminocarboxymethyldimethylsulfonium, ethylcarboxymethyldimethylsulfonium,
emrcaptomethyldimethylsulfonium, aminodimethylsulfonium,
methoxydimethylsulfonium, trimethyulsulfonium, mercaptodimethylsulfonium,
and salts thereof.
6. The feed composition of claim 1 wherein the feeding stimulator is a
compound of Formula (I) or salt thereof.
7. The feed composition of claim 6 wherein the compound of Formula (I) is
carboxymethyldimethylsulfonium or carboxyethyldimethylsulfonium.
8. The feed composition according to claim 1, which was obtained by adding
an aqueous solution containing 10.sup.-10 to 10.sup.-1 M of said feeding
stimulator to said at least one feed component (i).
9. The feed composition according to claim 2, which was obtained by adding
an aqueous solution containing 10.sup.-10 to 10.sup.-1 M of said feeding
stimulator to said at least one feed component (i).
10. The feed composition according to claim 1, wherein said at least one
feeding stimulator (ii) is in an amount of from 9.0.times.10.sup.-7 to
3.0.times.10.sup.5 ppm based on the total of said feed composition.
11. The feed composition according to claim 1, wherein said at least one
feeding stimulator (ii) is in an amount of from 1.08 .times.10.sup.-5 to
1.08.times.10.sup.-4 ppm based on the total of said feed composition.
12. The feed composition according to claim 2, wherein said at least one
feeding stimulator (ii) is in an amount of from 1.08.times.10.sup.-5 to
1.08.times.10.sup.-4 ppm based on the total of said feed composition.
13. The feed composition of claim 11 wherein said at least one feed
component (i) is a cellulosic powder.
14. The feed composition of claim 12 wherein said at least one feed
component (i) is a cellulosic powder.
15. The feed composition of claim 13 wherein said at least one feed
component (i) is a cellulosic powder.
16. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 1 to a site containing said at
least one of fishes and shellfishes.
17. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 2 to a site containing said at
least one of fishes and shellfishes.
18. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 3 to a site containing said at
least one of fishes and shellfishes.
19. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 8 to a site containing said at
least one of fishes and shellfishes.
20. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 9 to a site containing said at
least one of fishes and shellfishes.
21. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 10 to a site containing said at
least one of fishes and shellfishes.
22. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 11 to a site containing said at
least one of fishes and shellfishes.
23. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 12 to a site containing said at
least one of fishes and shellfishes.
24. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 13 to a site containing said at
least one of fishes and shellfishes.
25. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 14 to a site containing said at
least one of fishes and shellfishes.
26. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 15 to a site containing said at
least one of fishes and shellfishes.
27. The feed composition of claim 1, wherein the feeding stimulator is
carboxymethyldimethylsulfonium and the feed component is a cellulosic
powder.
28. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 27 to a site containing said at
least one of fishes and shellfishes.
29. The feed composition of claim 1, wherein the feeding stimulator is
carboxyethyldimethylsulfonium and the feed component is a cellulosic
powder.
30. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 29 to a site containing said at
least one of fishes and shellfishes.
31. The feed composition of claim 1, wherein the feeding stimulator is
selected from the group consisting of dimethylthetin,
dimethyl-beta-propiothetin, carboxymethyldiethylsulfonium,
carboxymethyldipropylsulfonium, carboxyethyldiethylsulfonium,
carboxyethyldipropylsulfonium, carboxymethyldibutylsulfonium,
carboxymethyldipentylsulfonium, carboxypropyldimethylsulfonium,
carboxybutyldimethylsulfonium, carboxypentyldimethylsulfonium,
carboxymethysulfonium, carboxymethyldiaminosulfonium,
carboxymethyldimethoxysulfonium, carboxymethylmethylmercaptosulfonium and
salts thereof.
32. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 31 to a site containing said at
least one of fishes and shellfishes.
33. The feed composition of claim 1, wherein the feeding stimulator is
dimethyl-.beta.-propiothetin.
34. A method of feeding at least one of fishes and shellfishes by providing
the feed composition according to claim 33 to a site containing said at
least one of fishes and shellfishes. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a feeding stimulator for fishes and
shellfishes, that can increase feed consumption of fishes and shellfishes
and results in growth promotion thereof, and a feed (including a bait)
containing the stimulator.
2. Background Information
In recent years, overfishing of fishery resources has caused world-wide
problems, and 200 nautical mile fishery rights have been established to
protect the fishery resources in every country. Under such circumstances,
hauls of adjacent sea surface fishes or cultured fishes tend to increase
year by year.
However, for the breeding of the adjacent sea surface fishes or cultured
fishes, raw feeds and fish powder are fed in the sea in such a large
quantity that the feeds that have not been taken by fishes settle on the
sea floor to cause contamination of a continental shelf. A low effective
utilization of feeds also causes an increase in cost.
For this reason, aquaculture industries have desired the development of a
feed that can achieve a high feed efficiency and a low cost, more
specifically, a substitute feed that can maintain the same feed efficiency
as in the mixed feeds in which the raw feeds and fish powder are used.
As one of researches for such purposes, reports have been made on feeding
stimulators that stimulate the olfactory sense or gustatory sense of
fishes to urge them to take feeds. Glutamine is known as a typical example
thereof, but, under the existing conditions, no remarkable effect can be
obtained when it is mixed in feeds.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a feeding stimulator for
fishes and shellfishes that stimulates the gustatory sense or olfactory
sense of fishes and shellfishes to enhance the feed efficiency, and a feed
containing the same.
To achieve the above object, the feeding stimulator for fishes and
shellfishes according to the present invention is characterized by
comprising at least one selected from the compounds, or salts thereof,
represented respectively by the following Formulas (I) to (VI):
##STR1##
wherein R.sub.1 and R.sub.2 may be the same or different and each
represent a hydrogen atom, an oxygen atom, a halogen atom, a saturated
hydrocarbon group, a saturated heterocyclic group, an unsaturated
hydrocarbon group, an unsaturated heterocyclic group, a carboxy group, a
thiocarboxy group. a dithiocarboxy group, a sulfo group, a sulfino group,
a sulfeno group, a haloformyl group, a carbamoyl group, a
hydrazinocarbonyl group, a cyano group, a nitrilo group, an isocyano
group, a cyanato group, a thiocyanato group, an isothiocyanato group, a
thioketone group, a formyl group, an oxo group, a thioformyl group, a
thioxo group, a hydroxy group, a mercapto group, a hydroperoxy group, an
amino group, an imino group, a hydrazino group, a nitro group, a nitroso
group, a diazo group, an azido group, an alkyloxy group, an alkylthio
group, an alkyldioxy group, an alkyloxycarbonyl group, a dithio group, a
trithio group, a polythio group, or a composite group of any of these;
X.sup.- represents a monovalent anion; and n is an integer of
0.ltoreq.n.ltoreq.20.
##STR2##
wherein R.sub.1, R.sub.2 and X.sup.- are the same as defined above; and
R.sub.3 represents a group having --(CH.sub.2).sub.n --as a basic
skeleton, to one or more of carbon atoms of which the group(s) same as
R.sub.1 and R.sub.2 is/are bonded or one or more of carbon atoms of which
undergo/undergoes dehydrogenation to form one or more of double bonds or
triple bonds.
##STR3##
wherein R.sub.1, R.sub.2, X.sup.- and n are the same as defined above; and
R.sup.4 is the same as defined for the above R.sub.1 and R.sub.2.
R.sub.1 --S--R.sub.2 (IV)
where R.sub.1 and R.sub.2 are the same as defined above.
##STR4##
where R.sub.1 and R.sub.2 are the same as defined above; and m is an
integer of 1 to 4.
##STR5##
wherein X.sup.- and n are the same as defined above; and R.sub.5, R.sub.6,
R.sub.7 and R.sub.8 are the same as defined for the above R.sub.1 and
R.sub.2.
The feed for fishes and shellfishes according to the present invention is
characterized by a feed to which the above feeding stimulator is added.
The present invention also provides a method of using the above compound or
a salt thereof as a feeding stimulator by adding it in a feed for fishes
and shellfishes to increase feed efficiency.
As shown in Examples set out hereinbelow, the above feeding stimulator was
confirmed to have the action of stimulating the olfactory sense or
gustatory sense of fishes and shellfishes to promote the appetite of
fishes and shellfishes. Accordingly, addition of this feeding stimulator
enables enhancement of feed efficiency in aquaculture or the like of
fishes and shellfishes. Also, even when a substitute feed available in a
low cost is used, it becomes possible to maintain the same feed efficiency
as the mixed feeds in which raw feeds and fish powder are used.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic view of an equipment used in experiments for testing
feeding-stimulation effect to fishes on various stimulators;
FIG. 2 is a schematic view illustrating a laboratory equipment used in
measurement of an electrical response from an olfactory tract of a fish;
FIG. 3 is an enlarged view of the main part of the equipment of FIG. 2;
FIG. 4 is a main part enlarged view of FIG. 2 to illustrate details of the
manner of the above described experiments;
FIG. 5A is a view showing an electrical response observed when 1-.sup.-3 M
of dimethyl-.beta.-propiothetin was added in the above described
experiments;
FIG. 5B is a view showing an electrical response observed when 10.sup.-3 M
of glutamine was added in the above described experiments;
FIG. 6A is a view showing an electrical response observed when 10.sup.-6 M
of dimethyl-.beta.-propiothetin was added in the above described
experiments;
FIG. 6B is a view showing an electrical response observed when 10.sup.-6 M
of glutamine was added in the above described experiments:
FIG. 7 is a graph showing the growth progress of goldfishes when a feed to
which dimethyl-.beta.-propiothetin was added was fed;
FIG. 8 is a graph showing the growth progress of red sea breams when a feed
to which dimethyl-.beta.-propiothetin was added was fed;
FIG. 9 is a graph showing the growth progress of young yellowtails when a
feed to which dimethyl-.beta.-propiothetin was added was fed;
FIG. 10 is a schematic view of equipment used in experiments for testing
feeding-stimulation effect to shellfishes on various stimulators;
FIG. 11 is a perspective view showing how to prepare a specimen used in the
above described experiments;
FIG. 12 is a cross sectional view of the specimen in FIG. 11;
FIG. 13 is a perspective view showing the state evaluated as 1 in the above
described experiments;
FIG. 14 is a perspective view showing the state evaluated as 2 in the above
described experiments;
FIG. 15 is a perspective view showing the state evaluated as 3 in the above
described experiments; and
FIG. 16 is a perspective view showing the state evaluated as 4 in the above
described experiments.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The feeding stimulator for fishes and shellfishes according to the present
invention comprises at least one selected from the compounds, or salts
thereof, represented respectively by the above Formulas (I) to (VI).
The compound of the above Formula (I) can be synthesized, for example, by
the reaction according to the following scheme:
##STR6##
Preferred examples of the compound represented by Formula (I) may include
the following:
##STR7##
The compound of the above Formula (II) can be synthesized, for example, by
the reaction according to the following scheme:
##STR8##
wherein R.sub.5 is the same as defined for R.sub.1 and R.sub.2.
##STR9##
Preferred examples of the compound represented by Formula (II) may include
the following:
##STR10##
The compound of the above Formula (III) can be synthesized, for example by
the reaction according to the following scheme:
##STR11##
Preferred examples of the compound represented by Formula (III) may include
the following:
##STR12##
The compound of the above Formula (IV) can be synthesized, for example, by
the reaction according to the following scheme:
R.sub.1 I+R.sub.2 SNa.fwdarw.R.sub.1 --S--R.sub.2 +NaI
Preferred examples of the compound represented by Formula (IV) may include
the following:
##STR13##
The compound represented by Formula (V) can be prepared by oxidation of the
compound represented by Formula (IV).
Preferred examples of the compound represented by Formula (V) may include
the following:
##STR14##
Preferred examples of the compound represented by Formula (IV) may include
the following:
##STR15##
In Formulas (I), (II), (III) and (VI), n may preferably be an integer of
0.ltoreq.n.ltoreq.10, and more preferably 0.ltoreq.n.ltoreq.5.
In R.sub.1 and R.sub.2 (similarly including R.sub.4, R.sub.5, R.sub.6,
R.sub.7 and R.sub.8), more preferred substituents include a hydrogen atom,
an oxygen atom, a halogen atom, a saturated hydrocarbon group, an
unsaturated hydrocarbon group, a carboxy group, a thiocarboxy group, a
dithiocarboxy group, a sulfino group, a sulfeno group, a haloformyl group,
a cyanato group, a formyl group, an oxo group, a hydroxy group, a mercapto
group, a hydroperoxy group, an amino group, an imino group, an alkyloxy
group, an alkylthio group, an alkyldioxy group, an alkyloxycarbonyl group,
a dithio group, a trithio group, a polythio group, or a composite group of
any of these.
Of these compounds represented respectively by Formulas (I) to (VI), the
compounds that can most strongly exhibit the feeding-stimulation effect to
fishes and shellfishes are carboxyethyldimethylsulfonium (or
dimethyl-.beta.-propiothetin), carboxyethyldimethylsulfonium (or
dimethylthetin), and choline.
The feeding stimulator of the present invention may be added in feeds of
various types as exemplified by synthetic feeds, semi-natural feeds and
wholly natural feeds, thereby bringing about the effect of increasing the
feed consumption of fishes and shellfishes and promoting the growth
thereof. This effect can be seen in all sorts of fishes including
fresh-water fishes as exemplified by carps, crucian carps, goldfishes,
eels, rainbow trouts and tilapias, and sea water fishes as exemplified by
young yellowtails, sea breams, spiny lobsters and bastard halibuts. It
also can be seen in all sorts of shellfishes such as top shells, abalones,
oysters, common scallops, ark shells, pearl oyster shells, hard clams,
surf clams and noble scallops.
The feed of the present invention is characterized by a feed to which the
above feed stimulator has been added, and any synthetic feeds,
semi-natural feeds and wholly natural feeds can be employed as the feed
serving as a base. The feed of the present invention can be effectively
used not only as feed in aquaculture of fishes and shellfishes, but also
as baits in angling.
There are no particular limitations on the manner of adding the feeding
stimulator, but the feed may preferably be prepared, for example, by
adding a solution containing 10.sup.-10 to 10.sup.-1 M of the feeding
stimulator. Here, if the concentration of the feeding stimulator in the
solution is less than 10.sup.-10 M, no sufficient feeding-stimulation
effect to fishes may be obtained, and if it is more than 10.sup.-1 M, a
bad smell tends to be generated to lower the effect. More preferably the
feed may be prepared by adding the above solution to raw materials for the
feed and kneading them together.
In general, the feeding stimulator of the present invention may be so added
in the feed as to be in an amount preferably of from 9.0.times.10.sup.-7
to 3.0.times.10.sup.5 ppm, and more preferably of from
1.08.times.10.sup.-5 to 1.08.times.10.sup.-4 ppm, based on the total
weight of the feed.
The present invention will be described below in greater detail by giving
Experiments and Examples.
Experiments
(1) Laboratory equipment and method
FIG. 1 illustrates equipment used in experiments for testing the feeding
stimulation effect on fishes of various stimulators. In the figure, the
numeral 1 denotes a water tank, which is supported on a pedestal 2. Fishes
3 are put in the water tank 1. A column 4 is set up on the side of the
water tank 1, and an arm 6 connected to a recording needle 5 is pivotably
supported on the column 4 through a pivot 7. To the rear end of the
recording needle 5, a thread 8 is connected, and a magnet 9 is fixed to
the lower end of the thread, which magnet 9 comes into close contact with
the bottom of the water tank, so that the thread is stretched. On the
middle of the thread 8, a feed 10 used in the experiments is attached at
the part immersed in the water in the water tank 1. On the other hand, a
recorder main unit 11 is provided at the side of the water tank 1, and a
reversed-L-shaped support is set up on the recorder main unit 11. Between
the support 12 and the recorder main unit 11, a rotating drum 13 is
rotatably supported, and the tip of the above recording needle 5 is
slidably in contact with the rotating drum 13. The rotating drum 13 is so
set as to make one revolution in 2 minutes and 50 seconds.
To describe the manner of experiments using the above described equipment,
the experimental feed 10 to which various feeding stimulators are each
added is prepared, which feed 10 is stuck on the thread 8 and immersed in
the water tank 1 at the position of an intermediate height in the water.
Then, the rotating drum 13 is revolved to record thereon the striking (or
biting) of the fishes 3 on the feed 10. More specifically, when the fishes
3 strike the feed 10, the thread 8 stretched by the magnet 9 is pulled, so
that the recording needle 5 vibrates to make a record on the rotating drum
13. Measured were the times the fishes 3 struck the feed 10 while the
rotating drum 13 makes one revolution. The water used in the experiments
was changed for each new one and at the same time the thread 8, the fishes
3 and the water tank 1 were thoroughly washed with rearing water.
(2) Preparation of feed
The experimental feed was prepared in the following manner: In regard to
base feeds, cellulose powder was used as a simple synthetic feed; an
equal-weight mixed feed of cellulose powder and powder of a commercially
available natural solid feed for carps, as a semi-natural feed; and the
above natural solid feed for carps, as an wholly natural feed. On the
other hand, prepared was an aqueous solution in which a substance on which
the feeding-stimulation effect is tested was dissolved in a concentration
of 10.sup.-3 M. Then, 0.5 g of the above base feed was taken up and 0.8 ml
of the above test solution was added therein, which were kneaded together
in a mortar to prepare a feed.
Preliminary Experiment: (Test on amino acid)
First, the feeding-stimulation effect on goldfishes was measured according
to the above method, in respect of several types of amino acids having
been hitherto reported as substances that strongly stimulate the gustatory
sense or olfactory sense of fishes and shellfishes. More specifically,
each amino acid was dissolved in water in a concentration of 10.sup.-3 M
to prepare a test solution, and 0.8 ml of the resulting test solution was
added to 0.5 g of cellulose powder, which were kneaded together to prepare
an experimental feed. The resulting feed was stuck on the thread of the
equipment described above to measure the times the goldfishes struck the
feed. A series of the measurements with these amino acids was repeated
three times. Results obtained are as shown in Table 1.
Table 1 shows relative values based on an evaluation made by assuming as
100 the times of striking on glutamine-added feed. In Table 1, the
abbreviations indicate as follows:
Gln: glutamine; Val: valine; Leu: leucine; Ser: serine;
Thr: threonine; Glu: glutamic acid; Arg; arginine; and
Lys: lysine.
Table 1 shows that glutamine contributes the best feeding effect as having
been hitherto reported, and glutamio acid, alginine, leucine and so forth
follow in that order.
TABLE 1
______________________________________
Amino acids
Gln Val Leu Ser Thr Glu Arg Lys
______________________________________
Relative
100 22.8 69.8 55.4 59.1 72.4 73.6 49.3
values 100 24.7 61.5 44.5 59.0 62.0 77.4 57.1
(%) 100 22.6 61.9 51.1 56.4 134.5 81.6 71.6
Average 100 23.4 64.4 50.3 58.2 89.6 77.5 59.3
______________________________________
EXAMPLE 1
(Experiments using simple synthetic feeds)
Experiments similar to the above were carried out using several types of
sulfur-containing compounds. More specifically, each substance was
dissolved in water in a concentration of 10.sup.-3 M to prepare a test
solution, and 0.8 ml of the resulting test solution was added to 0.5 g of
cellulose powder, which were kneaded together, thus preparing experimental
feeds. A feed obtained by adding 0.8 ml of water as it is, to 0.5 g of
cellulose powder and kneading them together was also used as a control.
These feeds were each stuck on the thread of the equipment described above
to measure the times the goldfishes struck the feed. The measurement was
repeated five times for each feed, an evaluation was made based on the
total number of the striking times. Results obtained are as shown in Table
2. In Table 2, two kinds of values are shown for the case where water was
added. This is because the corresponding measurements were respectively
carried out at the beginning, and the end, of the experiments.
Table 2 confirms the fact that the effect attributable to
dimethyl-.beta.-propiothetin much exceeds the effect attributable to the
glutamine having been hitherto reported as the substance that most
strongly stimulates the gustatory sense or olfactory sense in every sort
of fresh-water fishes and sea water fishes. A good effect was also found
in respect of dimethyl sulfide (corresponding to the left side of Formula
(I)), the decomposition product of dimethyl-.beta.-propiothetin.
TABLE 2
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Experiment times
Compound 1 2 3 4 5 Sum
______________________________________
Striking times
Water 4 0 1 4 0 9
Vitamin U 5 3 2 2 4 16
Taurine 5 0 9 24 12 50
Methylcysteine
2 10 2 26 16 56
Dimethyl sulfide
3 5 6 24 31 69
dimethyl-.beta.-propiothetin
15 20 25 47 36 143
Dithiazine 5 16 13 20 10 64
Glutamine 2 8 10 22 14 56
Water 2 12 13 11 21 59
______________________________________
Each paste was prepared by adding each test solution (10.sup.-3 M, 0.8 ml
to cellulose powder (0.5 g).
EXAMPLE 2
(Experiments using semi-natural feeds)
Next, using semi-natural feeds, experiments were carried out on
dimethyl-.beta.-propiothetin and glutamine. More specifically, to 0.5 g of
an equal-weight mixed feed of cellulose powder and powder of a natural
solid feed for carps, 0.8 ml of water or each test solution
(dimethyl-.beta.-propiothetin or glutamine in a concentration of 10.sup.-3
M) was added, which were kneaded together to prepare experimental feeds. A
feed obtained by adding 0.8 ml of water as it is, to 0.5 g of cellulose
powder and kneading them together was also used as a control. Using these
feeds, the times the goldfishes struck the feeds were measured in the same
manner as in Example 1. Results obtained are shown in Table 3.
Table 3 shows that the effect attributable to dimethyl-.beta.-propiothetin
is good also when the semi-natural feeds are used and, on the other hand,
no effect attributable to glutamine is seen when the semi-natural feeds
are used.
The feeding-stimulation effect attributable to dimethyl-.beta.-propiothetin
was also measured in the same manner as in the above except that crucian
carps were used as the fishes. Results obtained are shown in Table 4.
Table 4 shows that the feeding-stimulation effect attributable to
dimethyl-.beta.-propiothetin is seen also in respect of crucial carps.
TABLE 3
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Experiment times
Compound 1 2 3 4 5 Sum
______________________________________
Striking times
Water* 4 5 1 1 0 11
Mixed feed + H.sub.2 O**
22 40 17 15 19 113
Mixed feed + 32 27 33 44 21 157
dimethyl-.beta.-propiothetin**
Mixed feed + glutamine**
13 32 18 28 13 104
Water 4 1 1 0 0 6
______________________________________
*Prepared by adding water (0.8 ml) to cellulose powder (0.5 g).
**Prepared by adding water or each test solution (10.sup.-3 M, 0.8 ml) to
an equalweight mixed feed (0.5 g) of cellulose powder and a powdery
natural feed.
TABLE 4
______________________________________
Experiment times
Compound 1 2 3 4 5 Sum
______________________________________
Striking times
Water* 3 4 2 3 5 17
Mixed feed + H.sub.2 O**
7 8 9 13 7 44
Mixed feed + 7 15 10 23 11 66
dimethyl-.beta.-propiothetin**
Water 4 2 1 5 0 12
______________________________________
*Prepared by adding water (0.8 ml) to cellulose powder (0.5 g).
**Prepared by adding water or each test solution (10.sup.-3 M, 0.8 ml) to
an equalweight mixed feed (0.5 g) of cellulose powder and a powdery
natural feed.
EXAMPLE 3
(Experiments using natural feeds)
Nest, using natural feeds, experiments were carried out in the same manner
as in Example 2. More specifically, to 0.5 g of powder or a natural solid
feed for carps, 0.8 ml of water or each test solution
(dimethyl-.beta.-propiothetin in a concentration of 10.sup.-3 M) was
added, which were kneaded together to prepare experimental feeds. A feed
obtained by adding 0.8 ml of water as it is, to 0.5 of cellulose powder
and kneading them together was also used as a control. Using these feeds,
the times the goldfishes struck the feeds were measured to obtain the
results shown in Table 5, and the times the crucian carps struck the feeds
were measured to obtain the results shown in Table 6.
Tables 5 and 6 show that the effect attributable to
dimethyl-.beta.-propiothetin is seen also on both goldfishes and crucian
carps.
TABLE 5
______________________________________
Experiment times
Compound 1 2 3 4 5 Sum
______________________________________
Striking times
Water* 1 0 0 2 0 3
Natural feed + H.sub.2 O**
41 30 18 43 18 150
Natural feed + 56 32 12 64 49 213
dimethyl-.beta.-propiothetin**
Water 1 0 0 0 0 1
______________________________________
*Prepared by adding water (0.8 ml) to cellulose powder (0.5 g).
**Prepared by adding 0.8 ml of water or each test solution (10.sup.-3 M)
to a natural feed (0.5 g).
TABLE 6
______________________________________
Experiment times
Compound 1 2 3 4 5 Sum
______________________________________
Striking times
Water* 1 1 0 0 2 4
Natural feed + H.sub.2 O**
11 2 18 1 13 45
Natural feed + 15 6 24 7 8 60
dimethyl-.beta.-propiothetin**
Water 0 0 0 0 0 0
______________________________________
*Prepared by adding water (0.8 ml) to cellulose powder (0.5 g).
**Prepared by adding 0.8 ml of water or each test solution (10.sup.-3 M)
to a natural feed (0.5 g).
EXAMPLE 4
(Experiments using a decomposition product of dimethyl-.beta.-propiothetin)
To study the effect attributable to dimethyl-.beta.-propiothetin, dimethyl
sulfide, which is a constituent component and a decomposition product of
the dimethyl-.beta.-propiothetin, and acrylic acid were added to feeds,
respectively, to measure the feeding-stimulation effect to goldfishes.
Feeds used were those obtained by adding 0.8 ml of each test solution
(concentration: 10.sup.-3 M) to 0.5 g of cellulose powder and kneading
them together. Results obtained are shown in Table 7.
Table 7 clearly shows that the effect attributable to
dimethyl-.beta.-propiothetin is not the effect attributable to the
decomposition product of this compound, since the effect attributable to
dimethyl-.beta.-propiothetin distinctly exceeds the effects obtained when
both the dimethyl sulfide and acrylic acid were used alone or in
combination.
TABLE 7
______________________________________
Experiment times
Compound 1 2 3 4 5 Sum
______________________________________
Striking times
Water 0 0 0 1 0 1
Glutamine 6 7 15 25 8 61
Dimethyl-.beta.-propiothetin
12 20 11 23 5 71
Dimethyl sulfide (D)
8 12 11 14 5 50
Acrylic acid (A)
5 1 8 2 2 18
(D) + (A) 2 10 6 8 8 33
______________________________________
Each paste was prepared by adding 0.8 ml of water or each test solution
(10.sup.-3 M) to cellulose powder (0.5 g).
The above results are concerned with goldfishes or crucian carps, but the
effect attributable to dimethyl-.beta.-propiothetin was also confirmed in
instances in which other kinds of fishes were used.
EXAMPLE 5
(Rearing experiments)
To 100 g of an equal-weight mixed feed of cellulose powder and powder of a
natural solid feed for carps, 160 ml of water or a test solution
(dimethyl-.beta.-propiothetin in a concentration of 10.sup.-3 M) was
added, which were kneaded together to prepare experimental feeds. The
resulting feeds were fed in a dose of 0.05 g per one fish to rear crucian
carps for 30 days. As a result, a body weight gain was seen in 20% of the
crucian carps when using the feed to which no dimethyl-.beta.-propiothetin
was added, and 50% when using the feed to which
dimethyl-.beta.-propiothetin was added. Thus, employment of the feeding
stimulator of the present invention can also bring about the effect of
promoting the growth of fishes.
EXAMPLE 6
(Method of measuring electrical responses from olfactory tract)
FIG. 2, FIG. 3 and FIG. 4 illustrate an equipment for measurement of
electrical responses from an olfactory tract and a method therefor.
In the figures, the numeral 21 denotes a sealed box; 22, rearing water for
respiration; 23, rearing water for adding test solution; 24, a test
solution; 25, an input box; 27, ground; 28, an olfactory tract; 29, a
rhinencephalon; 30, a lobus opticus; 31, a cerebellum; 32 an experimental
fish; and 33, an electro-encephalograph.
As illustrated in the figures, the experimental fish 32 is set in the
sealed box 21. The experimental fish 32 has been anesthetized with
gallamine triethiodide (a muscle relaxant). Hence the fish cannot breathe
(i.e., gills do not move), and the rearing water 22 is introduced in the
oral cavity to supply oxygen. On the other hand, the rearing water 23 is
continually introduced into the nostril. Under this condition, the test
solution 21 is dropwise added to the flow of the rearing water 23, so that
the test solution 24 is mixed into the flow of the rearing water 23 and
reaches olfactory epithelial cells inside the nostril to give a stimulus.
This stimulus makes an electrical stimulus, which runs through the
olfactory tract 28, and is presumed to be transmitted to the
rhinencephalon 29, the lobus opticus 30 and the cerebellum 31 to cause a
feeding action. In the present experiment, this electrical stimulus is
taken out from electrodes, brought into contact with the olfactory tract
28 and transmitted to the input box 25, which goes out of the sealed box
21 from the input box 25, and is led to the electro-encephalograph 33, and
thus a stimulus wave is recorded in the electro-encephalograph 33.
An electrical response obtained by dropwise adding 10.sup.-3 M of
dimethyl-.beta.-propiothetin following the method as described above is
shown in FIG. 5A, and an electrical response similarly obtained by
dropwise adding 10.sup.-3 M of glutamine is shown in FIG. 5B. In the
figures, the arrow indicates a point of the time when the test solution
was dropwise added. Thus, the figures show that
dimethyl-.beta.-propiothetin and glutamine have almost similar stimulation
actions when added in a concentration of 10.sup.-3 M.
Next, an electrical response obtained by dropwise adding 10.sup.-6 M of
dimethyl-.beta.-propiothetin following the method as described above is
shown in FIG. 6A, and an electrical response similarly obtained by
dropwise adding 10.sup.-6 M of glutamine is shown in FIG. 6B. Thus, the
figures show that dimethyl-.beta.-propiothetin has an almost unchanged
stimulation action, while the glutamine shows a greatly decreased
stimulation action, when added in a concentration of 10.sup.-6 M.
Accordingly, the dimethyl-.beta.-propiothetin has the action to simulate
the olfactory tract of fishes even with a very small amount, and can be
said to be epock-making as a feeding stimulator.
EXAMPLE 7
Commercially available solid pellet feeds for goldfishes, red sea breams
and young yellowtails were each formed into powder, and added to 1 g of
the resulting powder was 0.5 ml each of an aqueous solution containing
dimethyl-.beta.-propiothetin in a concentration of 1 mM in the case of
fresh-water fishes or 5 mM in the case of sea water fishes, which were
kneaded together in a mortar, thus preparing feeds.
Using the feeds thus prepared and a feed to which an equal amount of water
was added in place of the aqueous dimethyl-.beta.-propiothetin solution,
respectively, goldfishes, red sea breams and young yellowtails were reared
to measure the rate of body weight gains.
For the goldfishes, 10 heads were reared using a styrol water tank having a
capacity of 3.5 l; and for the red sea breams and the young yellow tails,
5 heads each were reared using a styrol water tank having a capacity of
7.5 lit. The water temperature at the rearing was maintained at 20.degree.
to 22.degree. C. in all instances.
The goldfishes were fed twice a day in the morning and in the evening, and
the red sea breams and the young yellowtails were fed three times a day in
the morning, in the afternoon and in the evening. The fishes were fed in
such a manner that they may be fed up for 20 minutes at every time, and
the water was changed for new one after lapse of 20 minutes.
The rates of body weight gains of goldfishes, thus measured, are shown in
FIG. 7. In the figure, line a represents the results obtained when the
fishes were reared using the feed to which the aqueous
dimethyl-.beta.-propiothetin solution was added, and line b represents the
results obtained when they were reared using the feed to which water was
added in place of the aqueous dimethyl-.beta.-propiothetin solution. The
data of the measurements are indicated in average values of 10 heads.
The rates of body weight gains of the red sea breams, measured in the above
manner, are also shown in FIG. 8. In the figure, line a represents the
results obtained when the fishes were reared using the feed to which the
aqueous dimethyl-.beta.-propiothetin solution was added, and line b
represents the results obtained when they were reared using the feed to
which water was added in place of the aqueous dimethyl-.beta.-propiothetin
solution. The data of the measurements are indicated in average values of
5 heads.
The rates of body weight gains of the young yellowtails, measured in the
above manner, are further shown in FIG. 9. In the figure, line a
represents the results obtained when the fishes were reared using the feed
to which the aqueous dimethyl-.beta.-propiothetin solution was added, and
line b represents the results obtained when they were reared using the
feed to which water was added in place of the aqueous
dimethyl-.beta.-propiothetin solution. The data of the measurements are
indicated in average values of 5 heads.
These results tell that employment of the feeds to which
dimethyl-.beta.-propiothetin is added can bring about a much superior
growth promotion effect.
EXAMPLE 8
Using the laboratory equipment as illustrated in FIG. 1, the
feeding-stimulation effect to goldfishes were measured in respect of
various compounds according to the same method as in Example 1. Cellulose
powder was used as a base feed. Aqueous solutions in which the compounds
to be tested were respectively dissolved in a concentration of 10.sup.-3 M
were prepared. The above base feed was taken up in an amount of 0.5 g, and
0.8 ml each of the above aqueous solutions was added thereto, which were
kneaded together in a mortar, thus preparing feeds. The measurement was
repeated 5 times for each, and the sum of the times the fishes struck the
feeds in 5 times was calculated to make evaluation based on relative
values (relative striking strength) assuming as 100 the times the fishes
struck the dimethyl-.beta.-propiothetin-added feed. Results obtained are
shown in Table 8.
TABLE 8
______________________________________
(Compounds showing strong feeding-stimulation effect)
Relative
striking
Compound strength
______________________________________
Dimethyl-.beta.-propiothetin
100
(Compounds analogous to dimethyl-.beta.-propiothetin)
3-(Methylthio)-1-propanal 35
3-(Methylthio)-1-propylamine
32
3-(Methylthio)-1-propanol 41
2-Mercaptoacetic acid 63*
Methyl-3-(methylthio)-1-propanoic acid
59
3-(Methylthio)-1-propanoic acid
59
3-Mercaptopropanoic acid 59
Dimethylthetin 93**
(Compounds analogous to constituent
component of dimethyl-.beta.-propiothetin)
Dimethyl sulfide 43
Diethyl sulfide 45
Dipropyl sulfide 73**
Dibutyl sulfide 62*
Diallyl sulfide | | |
