High squalene content chicken eggs

Abstract

To provide a high value-added egg, a feed additive and feed for obtaining the high value-added egg, and methods using them.SOLUTION: The chicken egg of the present invention comprises a high content of squalene. The chicken egg of the present invention can be efficiently produced by using a strain belonging to Aurantiochytrium as feed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to squalene-rich chicken eggs, feed additives and feed for increasing the squalene content in chicken eggs, and methods for using them. More specifically, the present invention relates to obtaining squalene-rich chicken eggs by using algae belonging to the genus Aurantiochytrium in feed. [Background technology]

[0002] In recent years, the egg industry has seen a steady decline in egg prices due to the proliferation of large-scale corporate poultry farms. To boost profitability, functional eggs, obtained by hens fed diets supplemented with functional ingredients, are being produced as high-value-added eggs. For example, functional eggs containing iodine and vitamin E are already available under many brands. Eggs containing carotenoids such as astaxanthin and zeaxanthin are expected to not only benefit from their antioxidant properties but also improve the color of egg yolks (Patent Documents 1 and 2). Omega-3 fatty acids such as DHA and EPA, as well as medium-chain fatty acids, are believed to have the potential to reduce cholesterol, suppress body fat, and improve lifestyle-related diseases, leading to the production of functional eggs rich in these fatty acids (Patent Documents 3 and 4). The use of algae, such as chlorella to increase lutein and spirulina to increase zeaxanthin, as feed additives rich in functional ingredients has also been reported (Patent Documents 5 and 6).

[0003] Squalene is an isoprenoid hydrocarbon compound with six unconjugated double bonds. It is known for its various effects, including skin moisturizing, antioxidant activity, and liver function improvement, and is used in medicines, cosmetics, supplements, and other applications. Squalene is also biosynthesized in mammals, including humans, via the mevalonate pathway. It is primarily localized in the epidermis, where it contributes to skin moisturization (Non-Patent Document 1). Squalene is also an intermediate product leading to sterols such as cholesterol and a precursor to steroid hormones, which play an important role in maintaining life. Most squalene currently available is extracted from deep-sea shark liver oil, and attempts have been made to produce seafood with high squalene content (Patent Document 7). However, apart from its localization in the skin, squalene plays an important role in mammals as a component of sterols. Therefore, feeding squalene to chickens is likely to result in its conversion to sterols and its use in maintaining life. Therefore, it is unlikely that squalene would accumulate in the resulting eggs, and few attempts have been made to produce eggs with high squalene content. For example, Patent Document 8 attempts to produce functional eggs by adding shark liver oil to chicken feed, but does not even mention the accumulation of squalene in the eggs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-305057 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-170425 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-201472 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-288362 [Patent Document 5] Japanese Patent Application Laid-Open No. 2004-298062 [Patent Document 6] Japanese Patent Application Publication No. 10-155430 [Patent Document 7] Japanese Patent Application Publication No. 2017-77188 [Patent Document 8] US Patent Application Publication No. 2010 / 0278966 [Patent Document 9] Patent No. 6265407 [Patent Document 10] Patent No. 5942197 [Non-patent literature]

[0005] [Non-Patent Document 1] Oil Chemistry Vol. 39 No. 8 (1990) 525-529 [Non-patent document 2] World J Microbiol Biotechnol (2010) 26: 1303-1309 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides high-value-added eggs, feed additives and feed for obtaining high-value-added eggs, and methods of using them. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have succeeded in producing chicken eggs with high squalene and DHA contents by feeding chickens algae belonging to the genus Aurantiochytrium as feed.

[0008] The present application provides the following inventions: (1) Chicken eggs containing at least 4.0 mg / 100 g of squalene per 100 g of edible portion of the whole egg. (2) Chicken eggs containing at least 0.15 mg / g of squalene per gram of egg yolk. (3) A chicken egg according to (1) or (2), further containing at least 3.00 mg / g of DHA per 1 g of egg yolk. (4) A chicken feed additive for increasing the amount of squalene in chicken eggs, comprising algae of a strain belonging to the genus Aurantiochytrium. (5) The chicken feed additive according to (4), wherein the strain belonging to the genus Aurantiochytrium is a strain of Aurantiochytrium mangrove bay. (6) The chicken feed additive according to (5), wherein the Aurantiochytrium mangrove bay strain is Aurantiochytrium mangrove bay 18W-13a strain. (7) The chicken feed additive according to any one of (4) to (6), wherein the strain belonging to the genus Aurantiochytrium contains at least 1.0% by weight of squalene per dry weight of the algal cells. (8) The chicken feed additive according to any one of (4) to (7), wherein the algae are contained in an amount of 1.0% by weight to 20.0% by weight, calculated as dry algae, relative to the total weight of the feed. (9) A method for producing eggs with a high squalene content, comprising feeding chickens a feed containing the chicken feed additive according to any one of (4) to (8). (10) The chicken egg according to any one of (1) to (3), which is obtained by the method according to (9). [Effects of the Invention]

[0009] The eggs of the present invention contain a high content of squalene. The eggs of the present invention have the advantage that squalene can be easily ingested as a food. Furthermore, the eggs of the present invention contain not only high squalene but also high DHA. Furthermore, the aurantiochytrium used in the eggs of the present invention is a natural product, and is therefore preferable in terms of safety for humans who consume them. Furthermore, the method for producing eggs of the present invention allows for the easy production of eggs with a high squalene content at low cost, since aurantiochytrium can be mass-cultured and stored as dried algae. Furthermore, the squalene-rich eggs obtained by the present invention have the advantage that, compared to shark liver oil and other squalene-rich products currently available on the market, they do not have the odor characteristic of shark liver oil and can be used in cooking, etc., making them easier to ingest. [Brief explanation of the drawings]

[0010] [Figure 1]Figure 1 shows the change in the amount of squalene (mg / 100g) per 100g of edible portion in whole eggs produced by chickens fed diets containing or not containing algae from the Aurantiochytrium mangrove bay 18W-13a strain. [Figure 2] Figure 2 shows the change in the amount of squalene per gram (mg / g egg yolk) contained in the yolk of eggs produced by chickens raised on a diet containing or not containing algae from the Aurantiochytrium mangrove bay 18W-13a strain. [Figure 3] Figure 3 shows the change in the amount of DHA per gram (mg / g egg yolk) in egg yolks produced by chickens fed diets containing or not containing algae from the Aurantiochytrium mangrove bay 18W-13a strain. DETAILED DESCRIPTION OF THE INVENTION

[0011] Squalene (CAS number 111-02-4) is an isoprenoid hydrocarbon compound with six unconjugated double bonds. As mentioned above, squalene is also biosynthesized in mammals such as humans and chickens. However, because of its conversion to sterols and accumulation in sebum, it is unlikely that squalene will accumulate in eggs even if chickens are fed squalene. Therefore, few attempts have been made to produce eggs with a high squalene content.

[0012] However, as a result of extensive research, the present inventors have succeeded in increasing the squalene content in chicken eggs. The present invention is based on this finding by the inventors.

[0013] The present application provides chicken eggs with a high squalene content.

[0014] The squalene-rich chicken eggs of the present invention may have a squalene weight relative to the edible portion of the whole egg (total of egg white and egg yolk) of at least 3.0 mg / 100 g, at least 3.5 mg / 100 g, at least 4.0 mg / 100 g, at least 4.5 mg / 100 g, at least 5.0 mg / 100 g, at least 6.0 mg / 100 g, at least 7.0 mg / 100 g, etc., per 100 g of edible portion, preferably at least 4.0 mg / 100 g.

[0015] For example, in the case of an egg having an edible portion weighing 50 g, the squalene-rich chicken egg of the present invention may have a squalene weight relative to the edible portion of the whole egg (total of egg white and egg yolk) of at least 1.5 mg / egg, at least 1.75 mg / egg, at least 2.0 mg / egg, at least 2.25 mg / egg, at least 2.5 mg / egg, at least 3.00 mg / egg, at least 3.5 mg / egg, etc. Preferably, the squalene weight is at least 2.0 mg / egg.

[0016] Alternatively, the squalene-rich chicken eggs of the present invention may have a squalene weight relative to the egg yolk weight of at least 0.10 mg / g, at least 0.11 mg / g, at least 0.12 mg / g, at least 0.13 mg / g, at least 0.14 mg / g, at least 0.15 mg / g, at least 0.16 mg / g, at least 0.17 mg / g, at least 0.18 mg / g, at least 0.19 mg / g, at least 0.20 mg / g, at least 0.25 mg / g, etc.

[0017] Furthermore, the eggs of the present invention contain a high content of DHA. The amount of DHA, expressed by weight relative to the weight of the egg yolk, may be, but is not limited to, at least 1.00 mg / g, at least 1.50 mg / g, at least 2.00 mg / g, at least 3.00 mg / g, at least 4.00 mg / g (w / w), at least 5.00 mg / g (w / w), etc., per gram of egg yolk. Preferably, it is at least 3.0 mg / g.

[0018] The eggs of the present invention can be obtained by using algae belonging to the genus Aurantiochytrium in feed. Thus, the squalene-rich eggs of the present invention may be those in which, when fed the feed additive or feed of the present invention, the amount of squalene in eggs laid by hens is increased with a statistical significance level of 5% (e.g., Dunnett's test) compared to eggs not fed the feed additive or feed of the present invention (control), or may be those in which the amount of squalene is increased by, for example, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 100% or more, 200% or more, 300% or more, 400% or more, 500% or more, or more. The DHA-rich eggs of the present invention may be those in which, when fed the feed additive or feed of the present invention, the amount of DHA in the eggs laid by hens is increased with a statistical significance level of 5% (e.g., Dunnett's test) compared to eggs not fed the feed additive or feed of the present invention (control), or may be those in which the amount of DHA is increased by, for example, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 100% or more, 200% or more, 300% or more, 400% or more, 500% or more, or more.

[0019] The present invention also provides a feed additive and feed containing algae of a strain belonging to the genus Aurantiochytrium. Examples of strains belonging to the genus Aurantiochytrium include Aurantiochytrium mangrovei strains such as Aurantiochytrium mangrovei 18W-13a strain, and Aurantiochytrium limacinum strains such as Aurantiochytrium limacinum 4W-1b strain, Aurantiochytrium limacinum SR-21 strain, and Aurantiochytrium limacinum NIES3737 strain. In one embodiment, the Aurantiochytrium mangrovei 18W-13a strain is used. The Aurantiochytrium mangrovei 18W-13a strain is preferred.

[0020] The feed additive or feed of the present invention may contain any one of the above-mentioned algal cells of the strains belonging to the genus Aurantiochytrium, or may contain algal cells of two or more strains in any combination and ratio.

[0021] Strains belonging to the genus Aurantiochytrium can be cultured, for example, by seeding them in a medium such as GTY medium and culturing them under aerobic conditions, as in the Examples. Alternatively, the culture can be performed by any method known in the art, as described in Patent Documents 9 and 10, for example. However, improved methods for increasing the amount of squalene and DHA, as described in Non-Patent Document 2, for example, may also be used.

[0022] The algal cells of the genus Aurantiochytrium used in the present invention may contain, but are not limited to, at least 1.0 wt%, at least 2.0 wt%, at least 3.0 wt%, at least 4.0 wt%, at least 5.0 wt%, or more of squalene per dry weight of the algal cells after cultivation.Furthermore, the algal cells of the genus Aurantiochytrium used in the present invention may contain, but are not limited to, at least 1.0 wt%, at least 2.0 wt%, at least 3.0 wt%, at least 4.0 wt%, at least 5.0 wt%, or more of DHA per dry weight of the algal cells after cultivation.

[0023] The feed additive of the present invention may consist of or contain algae cells of the genus Aurantiochytrium, and can be blended in any amount, for example, so that the algae cells of the genus Aurantiochytrium in the feed additive of the present invention are present in an amount of 10 to 50 wt %, 20 to 80 wt %, 30 to 90 wt %, 50 to 80 wt %, 80 to 100 wt %, etc., calculated on a dry weight basis. However, this ratio will vary depending on the types and amounts of various components contained in the feed additive and feed, and is not limited to the above ratio as long as the effects of the present invention are achieved.

[0024] The algae of the genus Aurantiochytrium may be used as is, but if necessary, they may be processed by drying, pulverization, sterilization, washing, diluting the dried product with any solvent, etc., and then processed into various forms such as powder, liquid, solid, granules, particles, paste, etc., which can be selected as desired depending on the administration and storage conditions, etc.

[0025] The feed additive of the present invention can be incorporated into any chicken feed by adding the above-mentioned Aurantiochytrium algae directly or in combination with one or more other ingredients, such as excipients, carriers, and / or diluents.

[0026] The proportion of Aurantiochytrium algae in the feed of the present invention can be determined appropriately depending on the purpose, form, method of use, etc., and can be blended so that, for example, the proportion is 1.0 to 10 wt %, 1.0 to 20 wt %, 1.0 to 50 wt %, 2.0 to 40 wt %, 3.0 to 30 wt %, 4.0 to 20 wt %, 5.0 to 10 wt %, etc., calculated as dry weight.

[0027] The feed contains materials that are commonly used in feed preparation, such as processed products or extracts of animal or plant origin, oils and fats, carbohydrates, organic acids, vitamins, minerals, antibiotics, flavorings, coloring agents, preservatives, excipients, fillers, thickeners, adhesives, hydrating agents, disintegrants, emulsifiers, and / or pH adjusters, preferably in a manner that is suited to specific poultry farming conditions.

[0028] The feed and feed additives may be in any suitable form, for example, granules, powders, mixtures with ground grains, moist pellets, dry pellets, extruded pellets, flakes, pastes, cakes or tablets.

[0029] The present application also provides a method for producing squalene-rich eggs, which comprises feeding chickens a feed containing the feed additive of the present invention. The chickens to be fed the feed are not limited, and may be any type of chicken that can be raised and laid eggs using the feed, such as Julia, White Leghorn, Rhode Island Red, Barred Plymouth Rock, and Game Fowl.

[0030] The frequency of feeding the feed containing the feed additive of the present invention can be selected arbitrarily, such as, but is not limited to, once every two weeks, once a week, once every three days, once every two days, once a day, twice a day, three times a day, unlimited feeding, feeding as needed, etc. For example, when feeding is mechanized in chicken rearing, it may be more reasonable to automatically feed the chickens with a feed containing a fixed amount of Aurantiochytrium algae, rather than specifying the frequency.

[0031] The period for feeding the feed containing the feed additive of the present invention can be selected arbitrarily, such as, but is not limited to, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 1 month, 2 months, 3 months, 6 months, 1 year, 2 years, etc. For example, as shown in the Examples, the squalene and DHA contents in chicken eggs are increased 6 days after the start of feeding, and the feeding period can be extended to 12, 18, or 24 days to further increase the squalene content. [Example]

[0032] The present invention will now be described in more detail with reference to examples, although the present invention is not limited thereto.

[0033] Cultivation of Aurantiochytrium mangrove bay 18W-13a strain: The Aurantiochytrium mangrove bay 18W-13a strain, provided by the University of Tsukuba, was seeded into 60 L of GTY medium (1 L of 1 / 2 diluted seawater containing 20 g of glucose, 5 g of yeast extract, and 10 g of tryptone) in a sterilized 90 L jar fermenter. Aeration was controlled at 5-10 L / min and the agitation speed at 30-60 rpm to create aerobic conditions, and the culture was carried out at 25°C for 3 days. After cultivation, the algae were collected, frozen at -80°C, and dried in a freeze dryer to obtain dried algae.

[0034] Lipids were extracted from the dried algae and the squalene and DHA contents were measured using the analytical method described below. The dry algae contained 5.44% by weight of squalene and 4.31% by weight of DHA.

[0035] Feed preparation: A feed was prepared by mixing 5% by weight of the dried algae with Cure 17 (Showa Sangyo Co., Ltd.), a compound feed for adult chickens (hereinafter referred to as 18W-13a 5% mixed feed). The raw materials contained in Cure 17 and their blending ratios (by weight) are shown in Table 1 below. [Table 1]

[0036] Feeding test: Twelve Julia Shiratama layer hens, normally fed Cure 17 at the Ibaraki Prefectural Livestock Center, were divided into two experimental groups (six birds per group). Experimental group 1 was the test group and was fed a 5% 18W-13a mixed diet, while Experimental group 2 was the control group and was fed a normal diet. Feeding was ad libitum, with feeding starting on day 0 and continuing for a total of 76 days through day 75. Eggs were collected daily during the experimental period, and the number of eggs laid per hen was counted. Eggs were collected once a week, and the weights of the whole eggs and yolks were measured. Lipids were extracted from the yolks, and the lipid, squalene, and DHA contents were measured. The lipid, squalene, and DHA contents were converted to whole egg values, and the averages for the experimental and control groups were calculated.

[0037] After the feeding experiment, all test groups were fed normal feed, and the lipid, squalene, and DHA contents of the eggs collected 14 days later were measured.

[0038] Analysis method: The lipid content of the algae and egg yolk was measured by adding a chloroform / methanol (volume ratio 2:1) mixture to the sample, mixing thoroughly, adding 0.9% NaCl aqueous solution, further mixing, centrifuging, and then collecting the chloroform layer, concentrating it to dryness, and measuring the resulting lipid content. The squalene content was measured by adding squalane as an internal standard to the lipid, adding 1M KOH ethanol solution, and performing a saponification reaction at 90°C for 1 hour. The resulting unsaponifiable matter was measured by gas chromatography. The DHA content was measured by adding tricosane methyl ester as an internal standard to the lipid, adding 0.5M NaOH methanol solution, and performing a saponification reaction at 100°C for 9 minutes. Then, adding 14% boron trifluoride methanol solution, performing a methyl esterification reaction at 100°C for 7 minutes. The resulting fatty acid methyl esters were measured by gas chromatography.

[0039] result: Figure 1 shows the change in squalene content per egg over time, and Figure 2 shows the change in squalene content per gram of egg yolk over time. The squalene content per 100g of edible portion of whole eggs, per egg, and per gram of egg yolk in the test group fed a 5% 18W-13a mixed diet was more than double that of the control group on day 6, and more than tripled from day 14 onward. After three weeks of feeding, the squalene content in whole eggs and egg yolks remained above 4.00mg / 100g edible portion and 3.00mg / egg, respectively, and above 0.20mg / g, respectively. Furthermore, after the 76-day feeding trial, the test group was switched to a regular diet for two weeks, and the squalene content in the test group decreased, becoming comparable to that in the control group. In other words, by feeding 5% 18W-13a mixed feed, the squalene content in whole eggs was 3.00 mg / 100 g edible portion or more, 2.00 mg / egg or more, and the squalene content in egg yolk was 0.15 mg / g or more from the sixth day, and the squalene content in eggs was maintained at a high level while the feed was being given.

[0040] Figure 3 shows the change over time in the amount of DHA per gram of egg yolk. Compared to the control group, the DHA content in eggs from the test group fed a 5% 18W-13a mixed feed was more than twice as high by day 6 and more than three times higher from day 14 onwards. By feeding the 5% 18W-13a mixed feed, the squalene content in egg yolks reached 3.00 mg / g or higher from day 6, and the DHA content remained high throughout the feeding period thereafter. When the group was switched to a regular feed after 76 days, the DHA content in egg yolks decreased. [Industrial Applicability]

[0041] According to the present invention, chicken eggs containing a high content of squalene can be obtained.

Claims

1. A chicken feed additive for increasing the amount of squalene in chicken eggs, comprising algal cells of a strain belonging to the genus Aurantiochytrium, the strain containing squalene in an amount of at least 1.0% by weight per dry weight of the algal cells after cultivation, Here, "increase" refers to an increase in the amount of squalene in eggs laid by hens when the chicken feed additive is administered compared to when the chicken feed additive is not administered.

2. The chicken feed additive according to claim 1 , wherein the strain belonging to the genus Aurantiochytrium is a strain of Aurantiochytrium mangrove bayi.

3. The chicken feed additive according to claim 2, wherein the Aurantiochytrium mangrove bay strain is Aurantiochytrium mangrove bay 18W-13a strain.

4. The chicken feed additive according to any one of claims 1 to 3, wherein the strain belonging to the genus Aurantiochytrium contains at least 1.0 wt% of squalene per dry weight of algal cells.

5. The chicken feed additive according to any one of claims 1 to 4, wherein the algae bodies are contained in an amount of 1.0 wt% to 20.0 wt% in terms of dry algae bodies relative to the total weight of the feed.

6. A method for producing eggs with a high squalene content, comprising feeding chickens a feed containing the chicken feed additive according to any one of claims 1 to 5.

7. The chicken eggs are obtained by the method according to claim 6.

8. 8. The chicken egg of claim 7, containing at least 4.0 mg / 100 g of squalene per 100 g of edible portion of whole egg.

9. 9. The chicken egg according to claim 7 or 8, which contains at least 0.15 mg / g squalene per gram of egg yolk.

10. The chicken egg according to any one of claims 7 to 9, further comprising at least 3.00 mg / g DHA per 1 g of egg yolk.

Images