JP7753598B2 - Insect larvae feed and method for rearing female larvae using the same - Google Patents

Description

The present invention relates to insect feed used for raising insect larvae and a method for raising larvae using the insect feed.

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 growth. A decline in sardine catches could lead to a protein shortage, which could have an impact on food production.

Plant-derived proteins, which are considered as alternative proteins, have 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.

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.

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.

So we came up with the idea of processing beetle larvae, which are thought to be particularly rich in protein among insects, into protein and using them as feed.

Furthermore, in the field of insect rearing, methods for cultivating rhinoceros beetles and stag beetles using leaf mold or sawdust used for mushroom cultivation are known, but 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.

Patent No. 3816060

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 needed to raise large numbers of larvae. Furthermore, if larvae raised on feed containing chemically synthesized chemicals were used as alternative protein, there is a risk that residual chemicals could be released into the environment or concentrated in the bodies of livestock animals and humans, causing adverse effects.

The inventors' research has led them to discover that administering insect feed containing specific probiotic microorganisms and substances produced by these microorganisms to larvae promotes growth, accompanied by changes in the weight of the treated individuals, suggesting the potential for use as an alternative protein for raised insects.

In view of the above-mentioned problems, the present invention aims to provide a novel insect feed with growth-promoting effects and a low-cost method for rearing larvae using the same.

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 limit temperature for growth of 55°C or higher, and substances produced by the thermophilic bacteria through fermentation.

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.

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.

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.

Furthermore, insects from the order Coleoptera are preferred, and insects from the subfamily Stag Beetle are particularly preferred.

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 feed for saprophytic larvae.

As described above, according to the present invention, administering insect feed containing at least one of thermophilic bacteria and substances produced by thermophilic bacteria through fermentation to female insect larvae promotes growth accompanied by weight changes in the administered individuals, enabling efficient production of insect-derived protein, which can be provided as a low-cost alternative protein to existing protein sources.

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. 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.

Embodiments of the present invention are described in detail below with reference to the accompanying 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.

(How to raise larvae)
The larvae rearing method according to this embodiment (hereinafter referred to as "this 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.

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

Furthermore, among insects, examples of the order Coleoptera include the subfamily Stag Beetle, the family Lucanidae, and the subfamily Cetoniinae. In this case, the subfamily Stag Beetle is preferable because the larvae have a high growth rate and, in addition, the larvae are detritivorous, which means that the insect feed can be expected to be more effective. Furthermore, the feeding habits of the insects (larvae) to which the insect feed is administered do not have to be detritivorous, as long as they are herbivorous.

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 this method can be achieved.

(Composition of insect feed)
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 the thermophilic bacteria and thermophilic fermentation products themselves as feed in the present feed, and this also falls under the category of "addition."

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

Here, in the case of the genus Paenibacillus, an example is Paenibacillus cucumis.

Here, examples of the genus Bacillus include Bacillus coagulans, Bacillus subtilis, Bacillus thermolactis, and Bacillus hisashii.

Furthermore, although not limited to, the conjugate fungus NITE BP-1051 and the conjugate fungus ATCC PTA-1773 can be preferably used as conjugate fungus. Also, those containing Bacillus hisashii NITE BP-863 can be preferably used.

Thermophilic fermentation products herein refer to substances 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 secondary raw materials and fermenting them through a fermentation process in which the temperature is changed in stages 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) stages. The fermentation product may be in the form of a solid or liquid. If it is solid, it may also be in the form of a powder.

Furthermore, as long as this feed is administered to insects, it can be in a variety of forms, such as jelly, liquid, or powder. Furthermore, by processing this feed into a fine powder, it can be made into a form suitable for administration to small insects (larvae).

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

In addition, when it is in liquid form, in addition to the thermophilic bacteria and thermophilic fermentation products mentioned above, various additives can be added as long as they do not affect the effects of these bacteria, such as water and functional ingredients.

In addition, when it is in powder form, in addition to the thermophilic bacteria and thermophilic fermentation products mentioned above, various additives can be added as long as they do not affect the effects of these bacteria, such as fish meal or wheat flour.

In addition, it is preferable that the thermophilic bacteria or thermophilic fermentation products be added to this feed in a range of 0.01% by weight to 5% by weight.

Although there are no limitations on how insects are raised, it is preferable to feed them the above insect feed from hatching to larval development and the time they reach the final larval stage. In the case of the subfamily Stag Beetle, the growth period is preferably from the late second to mid-third instar, with administration particularly effective in promoting growth at the early third instar, when growth peaks.

The dosage of thermophilic bacteria or thermophilic fermentation products is not limited as long as the effects of the method are obtained, but it is preferable to administer between 0.008 g and 0.4 g per day per 100 g of body weight of early third-instar larvae of the subfamily Rhinoceros beetle.

As described above, this method demonstrates that administering insect feed supplemented with thermophilic fermentation products promotes growth and induces weight changes in the treated individuals, enabling insects to be reared efficiently and at low cost.

Here, we actually reared insects using the above rearing method and confirmed the effectiveness of the present invention. A detailed explanation follows.

(Insect feed 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 to homogeneity. 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.

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

(Administration to insects (larvae))
The insect feed containing the thermophilic fermentation product containing the prepared complex bacteria ATCC PTAA-1773, complex bacteria NITE BP-1051, and Bacillus hisashii NITE BP-863 was administered to each larva at a rate of 600 grams per larva (test group), and the fermented mat not containing the thermophilic fermentation product was administered to each larva at a rate of 600 grams per larva (control group).

The weight of male and female larvae in each test area was measured on days 0, 14, 28, 42, and 72 after administration.

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

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).

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).

Normally, 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, administering a thermophilic fermentation product containing the complex fungus ATCC PTAA-1773, the complex fungus 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.

These results demonstrate 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 promotes growth and results in changes in insect weight.

In addition, the thermophilic fermentation products added to the insect feed of the present invention can be produced using thermophilic fermentation bacteria from unused resources as raw materials, so they can be produced at lower cost than when using chemically synthesized chemicals, allowing insects to be raised efficiently and at lower cost. Furthermore, because thermophilic fermentation products are natural ingredients, they have little impact on the environment or living organisms and are highly safe.

In the above examples, an embodiment was described in which insect feed containing a mixture of thermophilic fermentation products containing the complex bacteria ATCC PTAA-1773, the complex bacteria 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]

This technology has industrial applicability as insect feed, a method for raising larvae, and a method for producing protein. It will also make it possible to raise large adult rhinoceros beetles and stag beetles, which are popular as pet toys, providing high-value-added products.

Claims (4)

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