Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Description
PET FOOD OR FEED
Field of the Invention
The present invention relates to a pet food or feed
reduced in an odor attributed to animal proteins,
particularly to meats.
Background of the Invention
A pet food market is growing owing to the recent pet
boom, but various problems are also increasing, on the
other hand. Due to changes in housing conditions or life
style, the number of pet owners are increasing in both
respects of their pets being fed indoors and outsides.
Under such situations, the offensive odor emitted from
remains of a pet food brings uncomfortable feeling not
only to pet owners but also to neighbors and the number of
such a problem is on the rise.
With regards to a feed, heightening of its protein
content and calorie has been promoted in order to raise
its nutritional efficiency. This accelerates emission of
an offensive odor originating from proteins, particularly
animal proteins. Moreover, the greater the breeding scale
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or breeding density, the more serious the problem of an
offensive odor becomes for neighbors.
A number of deodorants or aromatics for eliminating
the odor due to pets such as dogs and cats are now put on
the market. Cat litters and litter boxes imparted with a
deodorizing function were developed to mask the foul odor
of feces and urine. Japanese Patent Application Laid-Open
No. 74455/1988 proposed a cat food free of unsaturated
fatty acids which are causative of the odor of feces while
having cyclodextrin incorporated therein. Although this
cat food is capable of controlling the rancid odor emitted
from fish oil and the odor of feces, there are problems
such as high cost and insufficient effects. Also proposed
(in Japanese Patent Application Laid-Open No. 284865/1994)
is a pet food having cranberry incorporated therein to
mask the odor of feces and urine. However, this pet food
has a drawback that cranberry therein emits an odor.
Meanwhile, there remains no proposal to overcome the
problem of an offensive odor emitted from the remains of a
pet food in a feeding station. This problem is common not
only to pets but also to livestock.
On the other hand, spraying of a commercially
available deodorant or aromatic directly to a pet food or
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feed is not preferred from the viewpoint of safety.
A pet food or feed is composed mainly of meats,
grains, oils and fats, and water.
Meats to be used as a raw material are beef, pork,
fish meat, chicken, mutton and lamb and the like. In
practice, scraps of these meats, meat-and-bone meal and
organs are incorporated in a pet food or feed in the form
of meat meal or fish meal. As grains, soybean, wheat,
rice and corn have been used, while as oils and fats,
either animal ones or vegetable ones have been used.
Pet food or feed is usually produced by grinding,
kneading and extrusion of such raw materials and provided
in the kibble shapes. It is also provided as a bar of
jerky or a biscuit, or sometimes as dry powder. Heat
treatment is necessary for the production of these
products, and the production of canned food still requires
heat treatment after the process of filling the cans.
The foul odor of a pet food or feed is presumed to
come from animal proteins, particularly meats, or degraded
substances thereof. A preparation process of a pet food
or feed includes a heating step, which is conducted for
the purpose of sterilization and improvement in shelf life.
Upon heating, sulfur-containing compounds (such as
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thiazines or thiolanes) or nitrogen containing compounds
(such as amines, pyrroles or piazines), each a degraded
product of animal proteins, are generated from the meat.
These sulfur-containing or nitrogen-containing compounds
cause much discomfort, so they are presumed to cause an
offensive odor of a pet food or feed.
The addition of an enzyme or citric acid thereto was
proposed as a method for deodorizing meats in the
processing of livestock meats or fishery products
(Japanese Patent Applications Laid-Open Nos. 44066/1979,
44067/1979, 9468/1985 and 15367/1991). However, it is not
suited for pet food or feed production because such
addition increases the cost and makes the preparation step
cumbersome, while addition of citric acid reinforces an
acid taste, thereby deteriorating palatability. The
followings are known techniques relating to addition of
monoglyceride and diglyceride to pet food and feed.
It is revealed that addition of a medium chain fatty
acid diglyceride to a feed is effective for prevention or
treatment of protozoan diseases (US 5462967 or EP
0519458B), but its effects against an offensive odor are
not sufficient. In Japanese Patent Applications Laid-Open
Nos. 174342/1989, and 2537/1989, it is described that
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monoglycerides and diglycerides derived from higher
unsaturated fatty acids such as docosahexaenoic acid (DHA)
or eicosapentaenoic acid (EPA) bring about effects for
promoting fish appetite or attracting fish. Monoglycerides
or diglycerides themselves contain DHA or EPA much, so it
is difficult to say that they have sufficient effects
against an offensive odor when used on land in forms of
pet food and feed. U.S Patent No. 4228195 proposed a
preparation process of a pet food by using fatty acid
monoglycerides including succinylated monoglyceride, but
it does not refer to an odor.
SUMMARY OF THE INVENTION
The present invention provides a pet food or feed
reduced in an offensive odor attributed to animal proteins,
particularly meats, without a cumbersome step.
The present inventor has found that an oil or fat
containing a specific diglyceride markedly reduces an
offensive odor attributed to animal proteins, particularly
meats.
The present invention thus provides a pet food or
feed which contains an oil or fat composition having the
following components (A) and (B):
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(A) 10 wt.% or more of diglycerides which contain,
as constituent fatty acids, 50 wt.% or more of unsaturated
C14-24 fatty acids and 40 wt.% or less of unsaturated fatty
acids having at least 20 carbon atoms and at least 4
carbon-carbon double bonds; and
(B) 20 wt.% or less of free fatty acids, wherein a
weight ratio of the diglycerides to monoglycerides
satisfies the following equation:
diglycerides/monoglycerides >_ 1.
The present invention also provides an offensive
odor controlling agent of a pet food or feed which
contains the above-described oil or fat composition; and a
method for ameliorating the offensive odor of a pet food
or feed, which contains incorporating the above-described
oil or fat composition in the pet food or feed.
The present invention also provides a pet food or
feed which contains the following components (C) and (D):
(C) 0.2 to 60 wt.% of animal proteins containing
myosin or actin; and
(D) 1 to 30 wt.% of an oil or fat composition
composed of 10 wt.% or more of diglycerides which contain,
as constituent fatty acids, 50 wt.% or more of unsaturated
C14-24 fatty acids and 40 wt.% or less of unsaturated fatty
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acids having at least 20 carbon atoms and at least 4
carbon-carbon double bonds, and 20 wt.% or less of free
fatty acids, wherein a weight ratio of the diglycerides to
monoglycerides satisfies the following equation:
diglycerides/monoglycerides >_ 1.
The pet food or feed according to the present
invention is reduced in an offensive odor attributed to
animal proteins, particularly meats, and therefore, does
not cause discomfort. It can be prepared without any
cumbersome step, only by replacing a part or the whole of
the oil or fat component of the pet food and feed of the
present invention with a specific oil or fat composition
of the present invention.
It is known that diglycerides tend not to accumulate
as a body fat (US 6004611) . A pet food or feed having
some or all of its oil/fat content replaced with
diglycerides can be expected to have such an effect.
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In one aspect, the invention relates to a pet food
or feed, which comprises: 0.2 to 60 wt.% of an animal
protein comprising myosin or actin; and 1 to 30 wt.% of an
oil or fat composition comprising 10 wt.% or more (based on
the oil or fat composition) of a diglyceride which comprises
as constituent fatty acids, 50 wt.% or more of an
unsaturated C14_24 fatty acid and 40 wt.% or less of an
unsaturated fatty acid having at least 20 carbon atoms and
at least 4 carbon-carbon double bonds, 20 wt.% or less
(based on the oil or fat composition) of a free fatty acid,
and a monoglyceride, wherein a weight ratio of the
diglyceride to the monoglyceride is >_ 1.
In a further aspect, the invention relates to a
pet food or feed, which comprises: 0.2 to 60 wt.% of animal
proteins containing myosin and actin; 1 to 30 wt.% of an oil
or fat composition composed of: (i) 15 to 99 wt.% of
diglycerides whose constituent fatty acids are composed of:
50 to 99 wt.% of unsaturated C14-24 fatty acids and having 1,
2 or 3 carbon-carbon double bonds; 0 to 10 wt.% of
unsaturated C20-24 fatty acids having at least 4 carbon-carbon
double bonds; and the remainder of C14-24 saturated fatty
acids; (ii) 0 to 20 wt.% of free fatty acids; (iii)
monoglycerides; and (iv) triglycerides which contain, as
constituent fatty acids, saturated or unsaturated C14-24 fatty
acids; optionally, 0.1 to 30% by weight of phytosterol; and
at least one other ingredient selected from the group
consisting of vegetable proteins, grains, brans, starch
cakes, saccharides, vegetables, vitamins and minerals,
wherein the diglycerides and the monoglycerides are
contained at a diglyceride/monoglyceride weight ratio of at
least 1.
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DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the term "pet food"
means pet food for pets such as dogs and cats, whereas the
term "feed" means feed for animals such as pigs, poultry and
fish.
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The oil or fat composition to be used in the pet
food or feed of the present invention contains 10 wt.%
(which will hereinafter be described "%", simply) or more,
preferably 15 to 99%, more preferably 30 to 99%, even more
preferably 50 to 95%, still more preferably 60 to 95% of
diglycerides in order to suppress an offensive odor
derived particularly from meats. As constituent fatty
acids, the diglycerides contain 50% or more, preferably 70
to 99%, more preferably 80 to 98% of unsaturated C14-24
fatty acids. Such diglycerides have marked effects for
suppressing an offensive odor, are readily available and
is easy in handling. The amount of constituent fatty
acids having less than 14 carbon atoms is preferably 0.5%
or less in consideration of effects and palatability.
Incorporation of 15 to 90% of a-linolenic acid is
preferred for exhibition of physiological effects of o3
fatty acids. The diglycerides preferably contain, as
constituent fatty acids, 40% or less, preferably 20% or
less, more preferably 10% or less, more preferably 0 to 5%,
even more preferably 0 to 2% of unsaturated fatty acids
which have at least 20 carbon atoms and have at least 4
carbon-carbon double bonds such as EPA, DHA or arachidonic
acid, from the viewpoints of oxidation stability and odor
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control. The remaining constituent fatty acids of the
diglycerides are preferably saturated C14-24 fatty acids.
In consideration of palatability, a weight ratio of
diglycerides to monoglycerides contained in the oil or fat
composition satisfies the following equation: diglycerides
(DG)/monoglycerides (MG) ? 1, preferably DG/MG = 2 to 1000,
more preferably DG/MG = 10 to 500, especially DG/MG = 40
to 300.
The diglycerides as described above can be obtained,
for example, by ester exchange reaction of glycerin with
an oil or fat selected from oils or fats having, as
constituent fatty acids, unsaturated C14-24 fatty acids (ex.
safflower oil, olive oil, cotton seed oil, corn oil,
rapeseed oil, soybean oil, palm oil, sunflower oil,
linseed oil, sesame oil; lard, tallow, fish oil or milk
fat, or fractionated, randomized, hydrogenated or ester
exchanged oil thereof) in the presence of a hydroxide of
an alkali metal or an alkaline earth metal; or by
esterifying reaction of glycerin with a fatty acid mixture
having a high content of unsaturated fatty acids derived
from the above-described oils or fats. The above-
described oils or fats may be used in combination. Excess
monoglycerides formed by the reaction can be removed by
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separating means such as molecular distillation or
chromatography. Although these reactions may be conducted
by the chemical reaction using an alkali catalyst as
described above, reaction effected under mild conditions
through an enzyme such as 1-, 3-position-selective lipase
or the like is preferred for oxidation stability and
preference.
The content of free fatty acids in the oil or fat
composition to be used in the pet food or feed of the
present invention is 20% or less, preferably 10% or less,
more preferably 5% or less, even more preferably 2% or
less, still more preferably 1% or less in consideration of
its tendency to emit an offensive odor from the oil or fat
composition and palatability.
As another component in the oil or fat composition,
triglycerides (TG) can be mentioned. Examples of them
include animal and vegetable oils or fats. Triglycerides
preferably have, as constituent fatty acids, saturated or
unsaturated C19_24 fatty acids. It is more preferred that
they contain 50 to 100%, preferably 70 to 100%, more
preferably 80 to 100% of unsaturated C14-24 fatty acids.
Addition of an antioxidant to the oil or fat
composition is preferred. Examples of the antioxidant
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include tocopherol, vitamin C, vitamin C fatty acid esters,
phospholipids, polyphenols, BHT, BHA, TBHQ, and natural
antioxidant components. To 100 parts by weight of the oil
or fat composition, the antioxidant is added preferably in
an amount of 0.01 to 0.5 part by weight, more preferably
0.02 to 0.3 part by weight.
The pet food or feed of the present invention is
prepared by mixing the oil or fat composition (Component
(D)) and an animal protein containing myosin or actin
(Component (C)).
The animal protein containing myosin or actin,
defined as Component (C) of the pet food or feed of the
present invention, is a protein contained in livestock
meats such as beef, pork, chicken, mutton and lamb, and
fish meat, and serves as an essential component for the
growth of pets or poultry. Example of the meat containing
animal protein include livestock or animal meats such as
beef, pork, mutton, lamb, rabbit meat, and kangaroo meat
and byproducts or processed products thereof; meats of
birds such as chicken, turkey, quail and ostrich, and
byproducts or processed products thereof; products
obtained by rendering the above-exemplified raw meats such
as meat balls, meat bone meals and chicken meals; and fish
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meats such as bluefin tuna, bonito, Japanese horse
mackerel, sardine, common scallop, turban shell and fish
meal. The pet food or feed contains 0.2 to 60%,
preferably 1 to 30%, of Component (C).
The protein as defined herein is that determined
from a nitrogen content by the Kjeldahl nitrogen
determination method (5.5 to 6.4, the Standard Tables of
Food Composition in Japan), whereas the animal protein is
found from the amount of myosin or actin quantified by
densitometry based on comparison with a sample of known
concentration by SDS-electrophoresis (SDS-PAGE) . Animal
proteins in meats contain 25 to 35% of myosin and 12 to
13% of actin. The pet food or feed of the present
invention contains 0.05 to 21.0% of myosin and 0.02 to
7.8% of actin.
The pet food or feed of the present invention
contains 0.2 to 60% of Component (C) and 1 to 30% of
Component (D), preferably 1 to 30% of Component (C) and 1
to 20% of Component (D) . Component (D) may be substituted
for the part or whole of the existing oil content in the
pet food or feed.
A weight ratio of the animal protein to the
diglycerides in the pet food or feed of the present
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invention preferably satisfies the following equation:
animal proteins/diglycerides = 100/0.1 to 1/150, more
preferably 100/1 to 1/30, even more preferably 10/1 to 1/4,
when effects on and offensive odor suppressing nutritional
balance are taken into consideration.
The pet food or feed of the present invention may
further contain phytosterol. To the feed, addition of
phytosterol in an amount of 0.1% or more, especially 0.5%
or more is preferred from the standpoint of imparting
better cholesterol lowering effects. The upper limit of
the phytosterol content may fall within a range of 0.1 to
30%. Phytosterols usable here include free compounds such
as a-sitosterol, R-sitosterol, stigmasterol, campesterol,
a-sitostanol, R-sitostanol, stigmastanol, campestanol and
cycloartenol, and esters thereof such as fatty acid esters,
ferulic acid esters, and cinnamic acid esters.
The base of the pet food or feed of the present
invention is prepared by mixing Components (C) and (D),
phytosterol which is to be added as needed, and vegetable
proteins, grains, brans, starch cakes, saccharides,
vegetables, vitamins and minerals. Examples of the
vegetable proteins include soybean protein, those of the
grains include wheat, barley, rye, milo, and corn, those
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of brans include rice bran and wheat bran, and those of
the starch cakes include soybean cake. The total content
of the vegetable proteins, grains, brans and starch cakes
is preferably 5 to 95% of the pet food or feed. Examples
of the saccharides include oligosaccharide, sugar, sucrose
and molasses and their content is preferably 2 to 80%. As
the vegetables, vegetable extracts are usable and the
vegetable content is preferably 1 to 30%. Examples of the
vitamins include A, B1, B2, D, E, niacin, pantothenic acid
and carotene and their content is preferably 0.05 to 10%.
Examples of the minerals include calcium, phosphorus,
sodium, potassium and iron and their content is preferably
0.05 to 10%. In addition, the pet food or feed of the
present invention may contain additives ordinarily
employed such as gelling agent, shape retainer, pH
regulator, seasoning, antiseptic and nutrition supplement.
During preparation, heating while purging with an inert
gas such as nitrogen or deaerating is effective and is
therefore preferred for controlling oxidation of the oil
or fat composition (D).
Examples
Example 1
An offensive odor controlling agent of the feed
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according to the present invention having the following
composition was prepared.
Oil or Fat Composition 1
By using Lipozyme IM (product of Novo Nordisk A/S),
650 parts by weight of rapeseed oil fatty acid and 107
parts by weight of glycerin were esterified at 40 C for 5
hours at 0.07 hPa, followed by the removal of the lipase
by filtration. The resulting reaction mixture was then
molecularly distilled at 235 C. The residue was washed
with water and then deodorized at 235 C for 1 hour,
whereby Oil or Fat Composition 1 was obtained.
Oil or Fat Composition 2
By using Lipozyme IM (product of Novo Nordisk A/S),
650 parts by weight of perilla oil fatty acid and 107
parts by weight of glycerin were esterified at 40 C for 6
hours at 0.07 hPa, followed by the removal of the lipase
by filtration. The resulting reaction mixture was then
molecularly distilled at 215 C. The residue was washed
with water and then deodorized at 215 C for 2 hours,
whereby Oil or Fat Composition 2 was obtained.
Oil or Fat Composition 3
By using Lipozyme IM (product of Novo Nordisk A/S),
650 parts by weight of rapeseed hydrogenated oil (IV=75)
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and 107 parts by weight of glycerin were esterified at
50 C for 4 hours at 0.07 hPa, followed by the removal of
the lipase by filtration. The resulting reaction mixture
was then molecularly distilled at 235 C. The residue was
washed with water and then deodorized at 235 C for 1 hour.
The resulting product was mixed with purified rapeseed oil
(product of Nisshin Oil Mills, Ltd.) at a weight ratio of
3:7, whereby Oil or Fat Composition 3 was obtained.
Oil or Fat Composition 4
Rapeseed oil (product of Nisshin Oil Mills, Ltd.)
was designated as Oil or Fat 4 and used as a comparative
product.
The glyceride composition and the diglyceride fatty
acid composition of each of these oil or fat compositions
were described below.
Table 1: Glyceride composition
Oil or fat composition 1 2 3 4
Triglycerides 13.5 17.0 74.4 98.5
Diglycerides 85.1 82.3 25.2 1.1
Monoglycerides 1.1 0.6 0.3 0.4
Free fatty acids 0.3 0.1 0.1 0.0
* Each oil was reacted with trimethylsilylation agent (a silylating agent TH,
Kanto Chemical Co.,
Ltd.) and the resulting silylated oils were analyzed by use of GLC equipped
with a capillary
column (DBTM-1, product of J & W) and hydrogen flame ionization detector.
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Table 2: Fatty acid composition of diglycerides and triglycerides
Oil or fat composition 1 2 3 4
C16:0 3.7 5.4 3.8 3.7
C18:0 1.8 3.4 12.0 1.8
C18:1 57.0 18.3 78.7 60.3
Diglyce rides C20:1 1.7 0.0 2.3 2.5
C22:1 1.0 0.0 0.0 1.4
C18:2 w6 21.9 15.2 0.2 20.5
C18:3 w3 10.5 56.5 0.0 8.4
C16:0 6.2 5.5 3.9 3.7
C18:0 2.6 3.4 1.8 1.8
C18:1 57.1 18.5 51.7 58.8
Trigly cerides C20:1 1.7 0.0 1.5 2.0
C22:1 1.0 0.0 0.9 1.0
C18:2w6 21.8 15.7 21.2 21.9
C18:3 w3 10.4 54.8 16.6 8.4
* Triglyceride fraction and diglyceride fraction were collected from each oil
by subjecting the oils
to column chromatography (Wako gel C-200, product of Wako Pure Chemical
Industries, Ltd.),
eluting triglycerides from the column with hexane, and then eluting
diglycerides from the column
with hexane/ether (70:30, v/v). The resulting each fraction was analyzed by
GLC according to
the method described in "2.4.1.2-1996, Preparation of methyl esters of fatty
acids" and "2.4,2.2-
1996, Fatty acid composition" of "Standard Analytical Methods for Fats and
Oils" (edited by the
Japan Oil Chemists' Society).
Example 2
Pet foods for dogs as shown in Table 3 were prepared
using the agents (oil or fat compositions) for controlling
the offensive odor of the feed prepared in Example 1.
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Table 3
Composition Invention Invention Invention Comparative
product 1 product 2 product 3 product 1
Corn 15 15 15 15
Meat meal 8 8 8 8
Wheat flour 26 26 26 26
Defatted soybean 20 20 20 20
fish powder 16 16 16 16
Beat pulp 4 4 4 4
Bone meal 2 2 2 2
Vitamins -minerals 4 4 4 4
Lard 3 3 3 3
Oil or fat composition 1 2 - - -
Oil or fat composition 2 - 2 - -
Oil or fat composition 3 - - 2 -
Oil or fat composition 4 - - - 2
Animal proteins 11 11 11 11
Myosin * 3.3 3.3 3.3 3.3
Actin* 1.4 1.4 1.4 1.4
*Content (%) in the pet food.
Measuring method: Myosin and actin were quantified using SDS-PAGE and an
animal protein
content was determined based on the amount quantified by SDS-PAGE. Described
specifically,
samples and a standard sample of known concentration were each subjected to
SDS-PAGE.
The resulting gel was taken out and dyed with bromophenol blue. The dyed
amount was then
measured by a densitometry (product of Amersham Pharmacia Biotech). After
preparation of a
calibration curve, myosin and actin were quantified. Based on these amounts,
the animal
protein content was calculated.
A panel of 5 experts made an organoleptic evaluation
of the odor of each of the pet foods based on the
following evaluation criteria.
Average scores of the five experts are shown in
Table 4. The advantage of the invention can be recognized
when an average score is 0.5 or more than that of the
comparative product.
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5: No odor
4: Almost no odor
3: Slight odor but not uncomfortable
2: A little offensive odor
S 1: An offensive odor
As evidenced by result in Table 4, an offensive odor
of any one of the invention products was reduced compared
with that of the comparative product.
Table 4
Invention Invention Invention Comparative
product I product 2 product 3 Product 1
3 Hours after opening of
pet food package 3.2 3.4 3.0 2.2
(allowed to stand at 20 C
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Example 3
Pig Feeds as shown in Table 5 were prepared.
Table 5
Composition Invention Invention Invention Comparative
roduct 4 product 5 product 6 product 2
Corn 45 45 45 45
Meat meal 15 15 15 15
Wheat flour 14 14 14 14
Defatted soybean 10 10 10 10
Fish meal 3 3 3 3
Beat pulp 4 4 4 4
Bone meal 2 2 2 2
Vitamins -minerals 3 3 3 3
Oil or fat composition 1 4 - - -
Oil or fat composition 2 - 4 - -
Oil or fat composition 3 - - 4 -
Oil or fat composition 4 - - - 4
Animal proteins 5 5 5 5
Myosin* 1.4 1.4 1.4 1.4
Actin* 0.4 0.4 0.4 0.4
* Content (%) in the feed.
In a similar manner to Example 2, organoleptic
evaluation of the odor was carried out.
Table 6
Invention Invention Invention Comparative
Product 4 product 5 product 6 Product 2
3 Hours after opening
of feed package 3.8 4.4 3.6 2.8
(allowed to stand at 20 C
Any one of the invention products is ameliorated in
an offensive odor compared with the comparative product.