Insect larvae feed and method for rearing female larvae using the same

Abstract

To provide novel feed for insects having a growth promoting effect and a method for breeding larvae using the same.SOLUTION: Feed for insects contains at least one of a thermophile that is a microbe with an optimal growth temperature of 45°C or higher or a growth limit temperature of 55°C or higher and a substance produced by the thermophile by fermentation. A larvae breeding method includes female larvae using the feed for insects.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an insect feed used for rearing insect larvae and a method for rearing larvae using the insect feed. [Background technology]

[0002] As the global population grows, the world's fish catch continues to increase. In particular, the catch of sardines, which are used as a protein source for feed and fertilizer, continues to increase, and there is no room for further increase in the catch. A decrease in sardine catches could lead to a protein shortage, which could have an impact on food production.

[0003] Plant-derived proteins, which are considered as alternative proteins, have a low content of lysine, an amino acid essential for animals, making their use as alternative feed for sardines problematic. Furthermore, plant-derived proteins are used as food all over the world, regardless of ethnicity or culture, making their mass use as feed difficult.

[0004] From the above perspective, there is a need for alternative proteins that are rich in amino acids that cannot be supplemented by plant proteins and that do not compete with humans for food.

[0005] In response to this, the inventors turned their attention to insects as a new protein source. Insects are used as food by 2 billion people worldwide, and in addition to their staple diet of plant protein, which is deficient in lysine, there is a culture of eating caterpillars and larvae, which are rich in lysine. However, eating insects is not common in developed countries such as Japan, and there is strong resistance to eating them due to their appearance.

[0006] Therefore, we thought of processing beetle larvae, which are thought to be particularly rich in protein among insects, into protein and using them as feed.

[0007] In addition, in the field of insect breeding, a method of cultivating rhinoceros beetles and stag beetles using leaf mold or sawdust media used for mushroom cultivation is known. However, Patent Document 1 below reports that adding about 0.4% of L-carnitine, a vitamin-like substance, to leaf mold causes rhinoceros beetle larvae to swell and the adults to grow larger. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 3816060 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in Patent Document 1, the L-carnitine added to rhinoceros beetle larvae to enlarge them must be chemically synthesized, which poses the problem of high costs when trying to secure the L-carnitine required for rearing a large number of larvae. Furthermore, if larvae reared on feed supplemented with chemically synthesized chemicals are used as alternative proteins, there is a risk that residual chemicals may be released into the environment or concentrated in the bodies of livestock animals and humans, causing adverse effects.

[0010] The inventors' research has led to the discovery that administering insect feed containing specific probiotic microorganisms and substances produced by these microorganisms to larvae has a growth-promoting effect accompanied by a change in the weight of the treated individuals, suggesting the possibility of using this as an alternative protein for raised insects.

[0011] In view of the above problems, the present invention aims to provide a novel insect feed having a growth-promoting effect and a low-cost method for rearing larvae using the same. [Means for solving the problem]

[0012] The insect feed according to one aspect of the present invention that solves the above problems comprises: The fermentation medium contains at least one of thermophilic bacteria, which are microorganisms with an optimum growth temperature of 45°C or higher or a limiting growth temperature of 55°C or higher, and substances produced by the thermophilic bacteria through fermentation.

[0013] In addition, the insect feed in this aspect is The thermophilic bacteria preferably contain at least one of Penibacillus cucumis, Bacillus coagulans, Bacillus subtilis, Bacillus thermolactis, and Bacillus hisashii.

[0014] In addition, the insect feed in this aspect is The content of thermophilic bacteria or substances produced by the thermophilic bacteria through fermentation is preferably 0.01% by weight or more and 5% by weight or less.

[0015] A method for raising insect feed according to another aspect of the present invention that solves the above problems comprises: The female larvae are reared using the insect feed.

[0016] In addition, insects of the order Coleoptera are preferred, and insects of the subfamily Stag Beetle are particularly preferred.

[0017] It is also preferable to feed and raise the insects with the above insect feed from the time they hatch until they develop into larvae and reach the final instar larval stage. This is particularly preferable as a feed for saprophytic larvae. [Effects of the Invention]

[0018] As described above, according to the present invention, by administering to female insect larvae insect feed containing at least one of thermophilic bacteria and substances produced by thermophilic bacteria through fermentation, growth promotion accompanied by weight changes in the administered individuals is achieved, and it becomes possible to efficiently produce insect-derived protein, which can be provided as an alternative protein to existing protein sources at low cost. [Brief explanation of the drawings]

[0019] [Figure 1]1 is a graph showing the weight gain rate of male rhinoceros beetle larvae administered with insect feed in an example of the present invention. [Figure 2] 1 is a graph showing the weight gain rate of female rhinoceros beetle larvae administered with insect feed in an example of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention can be implemented in many different forms and is not limited to the examples described in the following embodiments and examples.

[0021] (How to raise larvae) The method for rearing larvae according to this embodiment (hereinafter referred to as "the present rearing method") involves administering to insects the insect feed described below to which at least one of thermophilic bacteria and thermophilic fermentation products has been added.

[0022] Here, insects refer to "creatures belonging to the hexapoda order," and examples thereof include the order Hymenoptera, Coleoptera, Lepidoptera, and Diptera. In the case of Coleoptera, most of them are herbivorous, making it easy to adjust the composition of insect feed, and therefore the effects of this embodiment are more pronounced.

[0023] Furthermore, examples of insects in the order Coleoptera include the subfamily Stag Beetle, the family Lucanidae, and the subfamily Cetoniinae. In this case, the subfamily Stag Beetle is preferred because the larvae have an excellent growth rate and, in addition, the larvae have a scavenging diet, which makes it possible to expect a more effective insect feed. The feeding habits of the insects (larvae) to which the insect feed is administered are not limited to scavenging, as long as they are herbivorous.

[0024] Furthermore, the sex of the insect larvae to be reared is not limited, and they may be male or female, as long as the effects of the present method can be achieved.

[0025] (Insect feed composition) Furthermore, in the present rearing method, as described above, at least one of thermophilic bacteria and thermophilic fermentation products is added to the insect feed (hereinafter referred to as "the present feed"). Of course, it is also possible to use thermophilic bacteria and thermophilic fermentation products themselves as feed in the present feed, and this also falls under the category of "addition."

[0026] (Definition of Thermophiles) Here, thermophiles refer to "microorganisms with an optimum growth temperature of 45°C or higher, or a limiting growth temperature of 55°C or higher." Thermophiles are not limited as long as they are within the above definition, but are preferably Penibacillus, Bacillus, or a combination thereof.

[0027] In the case of the genus Paenibacillus, for example, Paenibacillus cucumis can be exemplified.

[0028] In this regard, examples of the genus Bacillus include Bacillus coagulans, Bacillus subtilis, Bacillus thermolactis, and Bacillus hisashii.

[0029] In addition, the conjugate fungus may preferably be, but is not limited to, conjugate fungus NITE BP-1051 or conjugate fungus ATCC PTA-1773, or a fungus containing Bacillus hisashii NITE BP-863.

[0030] Here, the thermophilic fermentation product refers to a substance produced by the thermophilic bacteria through fermentation. Specifically, examples include substances produced by fermenting small fish, shrimp, or other raw materials by mixing them with auxiliary raw materials and fermenting them through a fermentation process in which the temperature is changed stepwise from F0 (70-90°C), to F1 (45-60°C), to F2 (40-55°C). The thermophilic bacteria are added at either the F1 (45-60°C) or F2 (40-55°C) stage. The fermentation product may be in the form of a solid or liquid. If it is solid, it may be in the form of a powder.

[0031] Furthermore, as long as the present feed is administered to insects, it can be in a variety of forms, such as jelly, liquid, powder, etc. By processing the present feed into a fine powder, it can be made into a form suitable for administration to small insects (larvae).

[0032] In the case of a jelly-like form, in addition to the above-mentioned thermophilic bacteria and thermophilic fermentation products, various additives can be added as long as they do not affect the effects of these bacteria, such as gelatin, agar, water, functional ingredients, etc.

[0033] In addition, in the case of a liquid, in addition to the above-mentioned thermophilic bacteria and thermophilic fermentation products, various additives can be added as long as they do not affect the effects of these bacteria, such as water and functional ingredients.

[0034] In addition, in the case of powdered form, in addition to the above-mentioned thermophilic bacteria and thermophilic fermentation products, various additives can be added as long as they do not affect the effects of these bacteria, such as fish meal and wheat flour.

[0035] In addition, the thermophilic bacteria or thermophilic fermentation products are preferably added to the present feed in an amount ranging from 0.01% by weight to 5% by weight.

[0036] Although there are no limitations on the type of insect rearing, it is preferable to feed and rear the insects with the insect feed described above from the time they hatch until they reach the final larval stage. In the case of the subfamily Stag Beetle, the growth period is preferably from the late second instar to the middle third instar, and administration during the peak growth period, particularly the early third instar, is highly effective in promoting growth.

[0037] Furthermore, the dosage of thermophilic bacteria or thermophilic fermentation products is not limited as long as the effects of the present method are obtained, but it is preferable to administer, for example, 0.008 g or more and 0.4 g or less per day for 100 g of body weight of early third-instar larvae of the subfamily Rhinoceros beetle.

[0038] As described above, according to this method, administering insect feed containing thermophilic fermentation products promotes growth of the administered individuals, accompanied by a change in their weight, allowing insects to be raised efficiently and at low cost. [Example]

[0039] Here, insects were actually reared using the above rearing method, and the effects of the present invention were confirmed. A specific description will be given below.

[0040] (Insect food preparation) A thermophilic fermentation product containing approximately 90-99% by weight of the complex fungus ATCC PTAA-1773, approximately 1-10% by weight of the complex fungus NITE BP-1051, and a smaller amount of Bacillus hisashii NITE BP-863 than NITE BP-1051 was mixed with a fermentation mat (Tsukiyono Mushroom Garden Mushroom Mat) at 1% by weight and stirred until homogeneous. The thermophilic fermentation product can be added not only to commercially available insect feeds such as those mentioned above, but also to woody biomass, including thinned wood, sawdust, waste logs discarded after mushroom cultivation, and waste mushroom beds.

[0041] (Insects used) Hercules beetle (Dynastes hercules hercules) was used. Larvae 90±10 days after hatching (early third instar) were separated into males and females.

[0042] (Administration to insects (larvae)) The larvae were fed 600 grams of insect feed containing a mixture of thermophilic fermentation products containing the prepared complex bacteria ATCC PTAA-1773, complex bacteria NITE BP-1051, and Bacillus hisashii NITE BP-863 per larvae (test group), and 600 grams of fermented mats without the mixture of thermophilic fermentation products per larvae (control group).

[0043] The weights of male and female larvae in each test group were measured on days 0, 14, 28, 42, and 72 after administration.

[0044] The weights of male and female larvae in the test and control groups were measured (n=4), and a significance test was performed. The results are shown in the graphs of Figures 1 and 2. Detailed values ​​in the graphs of Figures 1 and 2 are also shown in Tables 1 and 2.

[0045] Figure 1 is a graph showing the weight gain rate of male larvae. There was no difference in the weight gain rate of male larvae between the test and control groups (see Table 1).

[0046] [Table 1]

[0047] Figure 2 is a graph showing the weight gain rate of female larvae. The weight gain rate of female larvae in the test group on days 28, 42, and 72 was significantly higher than that in the control group. Note that the * in Figure 2 indicates a significant difference in weight gain rate (p<0.05).

[0048] [Table 2]

[0049] Typically, female larvae of insects belonging to the subfamily Stag Beetle are smaller than male larvae, resulting in a large difference in weight between the sexes. However, administration of a thermophilic fermentation product containing the complex bacteria ATCC PTAA-1773, complex bacteria NITE BP-1051, and Bacillus hisashii NITE BP-863 significantly increased the weight of female larvae, reducing the weight difference between the sexes and confirming an overall increase in weight for all larvae of insects belonging to the subfamily Stag Beetle.

[0050] These results demonstrated that feeding insect feed containing a mixture of thermophilic fermentation products containing the complex bacteria ATCC PTAA-1773, complex bacteria NITE BP-1051, and Bacillus hisashii NITE BP-863 promoted growth accompanied by changes in insect weight.

[0051] Furthermore, the thermophilic fermentation products added to the insect feed of the present invention can be produced by fermenting thermophilic bacteria using unused resources as raw materials, and therefore can be produced at lower cost than when using chemically synthesized chemicals, allowing insects to be reared efficiently at lower cost. Furthermore, because thermophilic fermentation products are natural ingredients, they have little impact on the environment and living organisms and are therefore highly safe.

[0052] In the above examples, an embodiment was described in which insect feed containing a mixture of thermophilic fermentation products containing the complex strains ATCC PTAA-1773, NITE BP-1051, and Bacillus hisashii NITE BP-863 was used. However, the insect feed does not have to be a thermophilic fermentation product containing all of ATCC PTAA-1773, NITE BP-1051, and NITE BP-863; for example, it may be a thermophilic fermentation product containing only one of ATCC PTAA-1773, NITE BP-1051, or NITE BP-863. [Possibility of Industrial Applicability]

[0053] The method has industrial applicability as insect feed, a method for rearing larvae, and a method for producing protein. It also makes it possible to raise large adult rhinoceros beetles and stag beetles, which are popular as rearing toys, and provides high-value-added products.

Claims

1. The present invention comprises a thermophilic fermentation product produced by fermentation of a thermophilic bacterium, which is a microorganism having an optimum growth temperature of 45°C or higher or a limit growth temperature of 55°C or higher, the thermophilic fermentation product contains 90 to 99% by weight of the complex strain ATCC PTAA-1773, 1 to 10% by weight of the complex strain NITE BP-1051, and Bacillus hisashii NITE BP-863 in an amount less than NITE BP-1051; A diet for insect larvae characterized by significantly increasing the weight of female insect larvae and reducing weight differences due to sex differences.

2. 2. The insect larvae feed according to claim 1, wherein the content of the thermophilic fermentation product is 0.01% by weight or more and 5% by weight or less.

3. A method for rearing female larvae, comprising rearing female larvae using the insect larvae feed according to claim 1 or 2.

4. 4. The method for rearing female larvae according to claim 3, wherein the insect larvae are fed and reared with the insect larvae feed during the period from hatching to larval development and reaching the final instar larval stage.

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