WO2024013486A1

WO2024013486A1 - Rearing system for insect larvae, method of rearing insect larvae, method of producing a food product or a feed product from insect larvae

Info

Publication number: WO2024013486A1
Application number: PCT/GB2023/051816
Authority: WO
Inventors: Peter Edmond Vaughan Williams; Neil Frank NAISH
Original assignee: D Bug Ltd
Priority date: 2022-07-12
Filing date: 2023-07-11
Publication date: 2024-01-18
Also published as: GB202210215D0; GB2620587A

Abstract

Systems and methods for rearing insect larvae and for producing a food and/or feed products are disclosed. In one arrangement, a series of rearing receptacles are provided. Each rearing receptacle is configured to contain a larval admixture. A gate system enables switching of each of at least a subset of the rearing receptacles between an open state and a closed state. A controller controls at least the gate system to cause admixture to flow from one of the rearing receptacles to a subsequent rearing receptacle. Disclosed arrangements are particularly suitable for applications where large quantities of crop products are processed and low quality co-products are produced, such as soybean hulls in the context of soybean processing. Soybean hulls have been found to be an excellent substrate for the growth of insects. Co-location at a soy processing plant permits the use of soy products to optimise the growth of insects.

Description

REARING SYSTEM FOR INSECT LARVAE, METHOD OF REARING INSECT LARVAE, METHOD OF PRODUCING A FOOD PRODUCT OR A FEED PRODUCT FROM INSECT LARVAE

The present disclosure relates to rearing insect larvae, particularly for food and/or feed production.

Worldwide demand is growing for sustainable sources of high-quality protein. Insects offer a promising source. For example, with relatively simple rearing requirements, the larval stage of the yellow mealworm, Tenebrio molitor, offers great potential in terms of nutritional profile and scalability.

Known systems for mass production of insects such as the yellow mealworm use stacks of trays that each include specific quantities of insects introduced at the start of the growth period and enough feed for a defined growing time. To ensure that steady growth of the insect is achieved at the highest density possible, individual trays need to be attended periodically to deliver feed and water, to remove frass (insect waste), and to eventually harvest the insects in each tray. The approach requires a large amount of space for high volume production and is labour-intensive.

It is an object of the present disclosure to provide alternative systems and methods for rearing insect larvae that at least partially addresses one or more of the problems discussed above or other problems.

According to an aspect of the invention, there is provided a rearing system for insect larvae, comprising: a series of rearing receptacles, each rearing receptacle configured to contain a larval admixture comprising growth substrate and either or both of insect eggs and insect larvae; a gate system configured to enable switching of each of at least a subset of the rearing receptacles between an open state in which the rearing receptacle allows admixture to flow out of the rearing receptacle and a closed state in which the rearing receptacle prevents admixture from flowing out of the rearing receptacle; and a controller configured to control at least the gate system to cause admixture to flow from one of the rearing receptacles in the series to a subsequent one of the rearing receptacles in the series.

It has been found that a wide range of insect larvae thrive in a growth substrate that can flow in a similar way to a liquid. For example, yellow mealworm larvae develop well in a growth substrate comprising a fibrous material of irregular particles sizes ranging between about 5mm and 0.5mm. When the larvae are within this growth substrate, it is observed that the growth substrate and larvae flow in a similar way to a liquid. The present rearing system exploits these flow properties to enable better use of space in the rearing system. In the case of yellow mealworm larvae, when the insect larvae hatch from the egg they are approximately 1 mm long and grow to 10-12 mm in length within the first 4-5 weeks. During this nursery phase these larvae require less than 20% of the space required by the same larvae in their final weeks of development. The present rearing system allows the amount of space available to the insect larvae to be managed progressively so that less space is made available at early stages of larval development than at later stages of larval development. This promotes high growth rates and output quality, while making it possible for the rearing system to be relatively compact, thereby making optimal use of space where the rearing system is installed.

In an embodiment, the rearing system further comprises an admixture propulsion system configured to drive flow of the admixture between different rearing receptacles along the series and/or out of the series of rearing receptacles, and the driving of the admixture comprises driving a flow of the admixture over a base of a rearing track defining the rearing receptacles. This approach to moving the admixture exploits an observation that the combination of larvae and the growth substrate tends to flow like a liquid and can propelled by gentle pushing without traumatising the larvae. In contrast to conveyor belt alternatives, admixture can be moved out of each rearing receptacle independently of rearing receptacles earlier in the series of receptacles, for example one at a time. When provided in combination with a frass receiving system comprising a filter arrangement configured to allow frass to pass out of the receptacle under gravity (e.g., through a base of each of one or more of the rearing receptacles), the pushing of the flow of admixture over the base of the rearing track encourages efficient removal of frass through the base.

In an embodiment, the rearing system further comprises a frass receiving system configured to receive frass from one or more of the rearing receptacles, the frass receiving system comprising a filter arrangement configured to allow frass to pass into the frass receiving system while blocking movement of other components of the admixture into the frass receiving system, and the filter arrangement is configured to have different filter characteristics in different rearing receptacles. This configuration allows the frass removal process to adapt to the evolving properties of the admixture, taking into account in particular the increasing size of the larvae as they reach progressively more advanced stages of development.

In an embodiment, the rearing system comprises a frass propulsion system configured to drive movement of frass in the frass receiving system. In an embodiment, the frass propulsion system is configured to generate a flow of gas to drive the movement of the frass. In an embodiment, the system controls a temperature of admixture in one or more of the rearing receptacles by controlling one or more operating parameters of the frass propulsion system as a function of a measured temperature of the admixture in one or more of the rearing receptacles, wherein the one or more operating parameters includes one or more of the following: gas flow rate, gas heating power, gas cooling power. This arrangement uses a flow of gas to efficiently and compactly achieve two separate functionalities: removing frass efficiently and controlling the temperature of the admixture to ensure maintenance of optimal growing conditions for the larvae being reared.

In an embodiment, the rearing system comprises a sensor system configured to sense one or more characteristics of admixture in the series of rearing receptacles. In an embodiment, the sensor system is configured to determine one or more larval characteristics indicative of a stage of development of the larvae, such as one or more of: segment number, larval length, larval outline, larval shape; larval colour. Providing a sensor system capable of determining such characteristics makes it possible efficiently to automate various functionalities and/or detect anomalies. In an embodiment, the control of the gate system by the controller is based at least in part on the determined one or more larval characteristics. For example, the controller may control the gate system to move admixture between rearing receptacles when the larvae reach suitable levels of maturity.

In an embodiment, the system comprises the admixture and the admixture contains any products of soybean processing, such as soybean meal, soybean oil, and/or soybean hulls, at a concentration of at least 1%, optionally at least 5%, optionally at least 15%, optionally at least 25%, optionally at least 50%, optionally at least 75%, by weight of the admixture. In an embodiment, the system comprises the admixture and the admixture contains soybean meal at a concentration of at least 1%, optionally at least 5%, optionally at least 15%, optionally at least 25%, optionally at least 50%, optionally at least 75%, by weight of the admixture.

The commercial processing of soybeans results in the production of three main products: two high value products and one low value co-product. Soybean meal is one of the high value products, providing high value protein used in the production of food products for humans and feed for animals. Soybean oil is the other high value product and is used as an energy supplement in animal feed or as an oil for the production of biodiesel. The low value co-product is soybean hulls. Insect production is a process whereby insects are typically used to convert waste or low value materials into higher value products such as insect protein which can be used as a supplement in animal feed or for food for humans. However, while soybean meal is rich in dietary protein it also contains a number of antinutritional factors (ANFs), such as phytates, tannins, trypsin inhibitors and oligosaccharides. The inventors have recognized that bioprocessing and digesting soybean using insect larvae is a means of eliminating these key antinutritional factors and improving the value of the resultant larvae protein meal. Thus, the inventors have recognized that there are important advantages to be gained from including soybean meal in the growth medium, contrary to prejudices in the art which would suggest that soybean meal is intrinsically too high quality to use in growth medium for insect production. The use of soybean meal in the growth substrate is particularly desirable where the rearing is done at a soybean processing plant, which may be implemented particularly efficiently using the rearing systems disclosed herein, which make good use of space and lend themselves to retrofitting/incorporation into manufacturing facilities focusing on other products.

In an embodiment, the system comprises the admixture and the admixture contains soybean hulls at a concentration of at least 1%, optionally at least 5%, optionally at least 15%, optionally at least 25%, optionally at least 50%, optionally at least 75%, by weight of the admixture.

Soybean hulls are a co-product of soybean processing but have not to the inventors’ knowledge been reported as being a potential growth medium for insect larvae. The inventors have demonstrated that soybean hulls work well for this purpose, particularly in combination with the rearing systems disclosed herein. The soybean hulls provide a growth medium having desirable flow properties and have been shown to support efficient growth of insects.

According to an additional aspect of the invention, there is provided a method of rearing insect larvae, comprising: providing a series of rearing receptacles; providing larval admixture in at least a selected rearing receptacle in the series, the admixture comprising a growth substrate and either or both of insect eggs and insect larvae; using at least a gate system to cause the admixture to flow from the selected rearing receptacle into a subsequent rearing receptacle in the series by switching the selected rearing receptacle from a closed state in which the selected rearing receptacle prevents admixture from flowing out of the selected rearing receptacle to an open state in which the selected rearing receptacle allows admixture to flow out of the rearing receptacle.

According to an additional aspect of the invention, there is provided a method of producing a food product or a feed product, comprising: rearing insect larvae in an admixture until the insect larvae reach a target level of maturity; and collecting and processing the insect larvae that have reached the target level of maturity to produce the food product or the feed product, wherein the admixture comprises a growth substrate and the larvae, and: the admixture contains soybean meal at a concentration of at least 1% by weight of the admixture; and/or the admixture contains soybean hulls at a concentration of at least 1% by weight of the admixture.

Embodiments of the disclosure will now be further described, merely by way of example, with reference to the accompanying drawings.

Figure 1 is a schematic side view of an example rearing system for insect larvae.

Figure 2 is a schematic perspective view of a rearing system of the type depicted in Figure 1.

Figure 3 is a schematic side view of another example rearing system for insect larvae.

As exemplified in Figures 1-3, embodiments of the present disclosure provide a rearing system 2 for rearing insect larvae. The mature insect larvae may be processed for use in human, livestock, pet or aquaculture nutrition, for example as a protein supplement. An oil supplement may be obtained by pressing the insect bodies. The protein content of insect bodies contains a wide range of bioactive short chain amino acid peptides, which are known to have beneficial activity in the gut of the consuming species. A food product (for humans) or a feed product (for animals) may be produced by collecting and processing insect larvae that have reached a target level of maturity in the rearing system 2.

The rearing system 2 comprises a series of rearing receptacles 11, 12. In the examples of Figures 1-3, the series comprises two rearing receptacles 11, 12. In other embodiments, the series may comprise more than two rearing receptacles, such as three, four, five, six, or seven, rearing receptacles. Each receptacle 11, 12 is configured to contain a larval admixture. The larval admixture comprises growth substrate and either or both of eggs and larvae of the insect to be reared by the system 2. Larval admixture may be introduced into a first rearing receptacle 11 of the series in a range of manners, including for example via an admixture introduction conduit 6. At the point of introduction, the larval admixture may comprise eggs and/or small larvae. The eggs and/or small larvae may be input either directly from adult female beetles laying eggs into the growth substrate or from counted egg or larval aliquots delivered manually or via automated aliquot systems.

The rearing receptacles 11, 12 have progressively larger size along the series (e.g., a second receptacle in the series is larger than a first receptacle in the series, a third receptacle is larger than the second receptacle, etc.). The rearing receptacles 11, 12 can thereby accommodate progressively later stages of growth of larvae (i.e., larger, more mature larvae) in the larval admixture. For a fixed number of larvae in each rearing receptacle 11, 12, the rearing receptacle 11, 12 may be arranged to be optimal in size for different respective stages in the growth cycle of the larvae. Thus, later larval stages are provided more space according to their size by moving them to later rearing receptacles in the series. Thus, the aliquoting process mentioned above may be configured to deliver into the first rearing receptacle 11 the number of larvae appropriate to fully occupy a relatively large final rearing receptacle 12 of the rearing system 2 when the larvae are fully developed, while the small, nursery-stage larvae are provided only the space that they need in the smaller first rearing receptacle 11. In the example of Figures 1 and 2, a base of the second receptacle 12 has twice the surface area of a base of the first receptacle 11. The number of larvae to introduce will depend on the insect being reared and the optimal density for that insect. Typically, the number of larvae may be selected to achieve a density of about 5 to 10 larvae per cm³ of growth substrate. The depth of growth substrate is not particularly limited but may typically be up to about 10 cm. In the case of embodiments of the type depicted in Figures 1 and 2, the total area of the bases of the rearing receptacles 11, 12 is not particularly limited but may for example be up to about 5m long (e.g., 3-5m long) and about Im wide (e.g., 0.5 to 1.5m wide). By adapting the space available to the larvae as a function of their developmental stage it is possible not only to make better use of space but to keep the larvae in close proximity with each other, which is a condition that they prefer and which speeds their development.

The rearing system 2 further comprises a gate system. The gate system is configured to enable switching of each of at least a subset of the rearing receptacles 11, 12 between an open state and a closed state. In the open state, the rearing receptacle 11, 12 allows admixture to flow out of the rearing receptacle 11, 12. In the closed state, the rearing receptacle 11, 12 prevents admixture from flowing out of the rearing receptacle 11, 12.

The rearing system 2 further comprises a controller 4. The controller 4 may control and/or receive data from various different components of the rearing system 2. Example connections indicating such control and/or data flow are depicted by broken lines flowing from the controller 4 in Figure 1. The controller 4 controls at least the gate system. The controller 4 controls at least the gate system to cause admixture to flow from one of the rearing receptacles 11 in the series to a subsequent one of the rearing receptacles 12 in the series. Insect larvae often thrive in a growth substrate that provides an admixture with flow properties similar to a liquid. As described below, when the gate system allows flow out of a rearing receptacle 11, 12, the admixture may be driven to flow by an admixture propulsion system (as shown in Figures 1 and 2) or by gravity (as shown in Figure 3).

Thus, a method may be provided that includes providing larval admixture in at least a selected rearing receptacle 11 in the series, and using at least a gate system to cause the admixture to flow (by forced flow or by gravity) from the selected rearing receptacle 11 into a subsequent rearing receptacle 12 in the series by switching the selected rearing receptacle 11 from a closed state to an open state. The admixture is caused to flow from the selected rearing receptacle 11 to the subsequent rearing receptacle 12 when the larvae in the admixture have reached a stage of growth where the larvae would benefit from more space.

In some embodiments, as exemplified in Figure 1, the gate system comprises a plurality of rotatable barriers 21, 22. A first barrier 21 is positioned between a first rearing receptacle 11 and a second rearing receptacle 12 in the series. A second barrier 22 is positioned after the second rearing receptacle 12 in the direction of flow. In this example, the first barrier 21 and the second barrier 22 are pivotably mounted to allow the barriers 21, 22 to be rotated about rotation axes 23 vertical to the plane of the page. Electrical motors may be provided for driving rotation of the barriers 21, 22. By controlling the rotation of the barriers 21, 22 the controller 4 can thus switch the rearing receptacles 11, 12 between the open and closed states.

For example, the controller 4 can put the first receptacle 11 into the closed state by setting the first barrier 21 in a vertical position. In this closed state, admixture in the first rearing receptacle 11 will be constrained to remain in the first receptacle 11. The controller 4 can switch the first receptacle 11 into the open state by rotating the first barrier 21 anticlockwise (as exemplified by the broken line version 21 ’ of the first barrier 21 shown in Figure 1). In this open state, admixture in the first rearing receptacle 11 can flow into the second receptacle 12 (to the right).

Similarly, the controller 4 can put the second receptacle 12 into the closed state by setting the second barrier 22 in a vertical position. In this closed state, admixture in the second rearing receptacle 12 will be constrained to remain in the second receptacle 12. The controller 4 can switch the second receptacle 12 into the open state by rotating the second barrier 22 anticlockwise (as exemplified by the broken line version 22’ of the second barrier 22 shown in Figure 1). In this open state, admixture in the second rearing receptacle 12 can flow out of the second receptacle 12 (to the right).

In a variation on the arrangement of Figure 1, the rotatable barriers 21, 22 may be replaced by barriers that can be translated vertically between a lower position that blocks flow (corresponding to the closed state) and an upper position that allows flow (corresponding to the open state).

In some embodiments, as exemplified in Figure 3, the gate system comprises a plurality of valves 31, 32. A first valve 31 is positioned between a first rearing receptacle 11 and a second rearing receptacle 12 in the series. A second valve 32 is positioned after the second rearing receptacle 12. By controlling the valves 31, 32 to be open or closed the controller 4 can switch the rearing receptacles 11, 12 respectively between the open and closed states.

In the examples shown, the second receptacle 12 is the final rearing receptacle in the series. The second barrier 22 or second valve 32 thus serves as an outlet of the rearing system through which admixture can be expelled from the rearing system. By controlling at least the gate system the controller 4 can thus control when admixture is expelled from the rearing system by causing admixture to flow out of the final rearing receptacle.

In some embodiments, the controller 4 controls at least the gate system to cause admixture to flow into the final rearing receptacle (e.g., the second rearing receptacle 12 in the examples shown) from a directly preceding rearing receptacle (e.g., the first rearing receptacle 11 in the examples shown) after the admixture in the final rearing receptacle has flowed out of the final rearing receptacle (e.g., via the second barrier 22 or second valve 32 in the examples shown).

In embodiments comprising three or more rearing receptacles in the series, the controller 4 may be configured to control at least the gate system to cause admixture in each rearing receptacle prior to the final rearing receptacle to flow forward into a subsequent rearing receptacle in the series when space has been made available in the respective subsequent rearing receptacle by flow of admixture out of that rearing receptacle. Thus, when a dose of admixture is expelled from the rearing system, for example because the larvae in the dose are at a desired maturity, admixtures in earlier rearing receptacles may be pushed forwards by one rearing receptacle. Thus, if there are five rearing receptacles, after collecting admixture from the fifth (final) rearing receptacle, admixture in the fourth rearing receptacle would be moved into the fifth rearing receptacle, admixture in the third rearing receptacle would be moved into the fourth rearing receptacle, admixture in the second rearing receptacle would be moved into the third rearing receptacle, and admixture in the first rearing receptacle would be moved into the second rearing receptacle. This process would leave the first rearing receptacle empty and ready to receive a new batch of admixture at the earliest developmental stage. In some embodiments, as exemplified in Figures 1 and 2, the system 2 further comprises an admixture propulsion system. The admixture propulsion system drives flow of the admixture between different rearing receptacles 11, 12 in the series (e.g., from the first receptacle 11 to the second receptacle 12 in the example shown) and/or out of the series of rearing receptacles (e.g., out of the second receptacle 12 in the example shown). The driving of the admixture may comprise driving a flow of the admixture over a base 8 of a rearing track 10 defining the rearing receptacles 11, 12. In some embodiments, the rearing track 10 may be arranged horizontally to facilitate provision of a uniform thickness of admixture. The rearing track 10 may comprise an elongate channel having a substantially flat and horizontal base and two side walls running along opposite lateral sides of the elongate channel. The series of rearing receptacles 11, 12 may be defined by a respective series of rearing zones along the rearing track 10, separated from each other for example by one or more barriers 21 of the gate system. The rearing track 10 may for example be up to about 5m long (e.g., 3-5m long) and about Im wide (e.g., 0.5 to 1.5m wide).

In some embodiments, as exemplified in Figures 1 and 2, the propulsion system comprises one or more pushing members 41, 42. Each pushing member 41, 42 is moveable along the rearing track 10 to push a respective portion of the admixture along the rearing track 10. The propulsion system is configured to drive movement of each pushing member 41, 42, for example along rails using an electric motor. In the example shown in Figures 1 and 2, a first pushing member 41 is configured to push admixture from the first receptacle 11 into the second receptacle 12. An example intermediate position 41 ’ of the first pushing member 41 is depicted in broken lines. A second pushing member 42 is configured to push admixture out of the second receptacle 12. In some embodiments, the first barrier 21 or a portion of the first barrier 21 may be configured to act as the second pushing member 42. An example intermediate position 42’ of the second pushing member 42 is depicted in broken lines.

In some embodiments, as exemplified in Figure 3, the system 2 is configured so that gravity provides the force driving flow of admixture through the series of rearing receptacles 11, 12. In embodiments of this type, the rearing receptacles 11, 12 may be configured to have a sloped base, for example in the form of a funnel (as in the example of Figure 3) to guide flow of admixture in a desired manner. In the example of Figure 3, each receptacle is provided in a funnelled shape that guides flow of admixture onto a respective valve 31, 32.

In embodiments having an admixture propulsion system, the controller 4 may be configured to control both the admixture propulsion system and the gate system to achieve the desired flow of admixture through the rearing system 2. In embodiments of the type shown in Figures 1 and 2 for example, when admixture in the second receptacle 12 is ready for collection, the controller 4 may control the gate system to open the second barrier 22 by rotating the second barrier 22 anticlockwise and then control the admixture propulsion system to push the admixture in the second receptacle 12 out of the rearing system 2. The admixture may be pushed out by forward motion of the second pushing member 42 (to the right in the figure). The second pushing member 42 may then be moved back to its starting position (by movement to the left in the figure). The controller 4 then controls the gate system to close the second barrier 22 by rotation clockwise and open the first barrier 21 by rotation anticlockwise (which in the example shown includes also rotation of the second pushing member 42 which in this example forms part of the first barrier 21), and then controls the admixture propulsion system to push admixture in the first receptacle 11 forwards into the second receptacle 12. In the example shown, this is achieved by forward motion of the first pushing member 41 (to the right in the figure). The first pushing member 41 may then be moved back to its starting position (by movement to the left in the figure), the first barrier 21 closed, and new admixture added to the rearing system 2 by the admixture introduction conduit 6.

In some embodiments, as exemplified in Figures 1-3, the rearing system 2 further comprises a frass receiving system. The frass receiving system receives frass from one or more of the rearing receptacles 11, 12. The frass receiving system comprises a filter arrangement 8 that allows frass to pass into the frass receiving system while blocking movement of other components of the admixture (such as feed and/or larvae) into the frass receiving system. Managing frass levels in the admixture allows larvae to be reared in higher densities, improving growth rates and yield per volume.

In some embodiments, as exemplified in Figures 1-3, the frass receiving system is configured such that frass can pass from the one or more rearing receptacles 11, 12 to the frass receiving system under the action of gravity. The frass receiving system may comprise one or more frass receptacles 14 positioned underneath respective rearing receptacles 11, 12. In some embodiments, the frass receptacles 14 are provided in the form of tracks or channels that allow frass to be moved along them. As exemplified in Figure 1, a frass propulsion system 16 may be provided for driving movement of frass in the frass receiving system (e.g., along tracks or channels defined by the frass receptacles 14). The frass propulsion system 16 may be configured to generate a flow of gas to drive movement of the frass. In the example of Figure 1, the frass propulsion system 16 blows gas along a channel defined by the frass receptacle 14 from the right to the left in the orientation in the figure. The flow of gas entrains frass and ensures that the frass receptacle does not overfill with frass. In other embodiments, as exemplified in Figure 3, the frass receptacles 14 may be configured to promote movement of the frass along channels defined by the frass receptacles under the force of gravity, for example by including obliquely inclined surfaces. The rearing system 2 may be configured to direct frass towards containers to be collected. Frass often has commercial value independently of the final insect larvae, for example as a soil emollient and/or conditioning agent.

In some embodiments, the rearing system 2 is configured to control a temperature of admixture in one or more of the rearing receptacles 11, 12 by controlling one or more operating parameters of the frass propulsion system as a function of a measured temperature of the admixture in one or more of the rearing receptacles. In the case where the frass propulsion system uses a flow of gas, the one or more operating parameters may include one or more of the following: a gas flow rate, a gas heating power (i.e., a rate of transfer of heat energy to the gas), a gas cooling power (i.e., a rate of transfer of heat energy out of the gas). Thus, a temperature of the admixture may be controlled by controlling a gas flow that entrains frass in a region adjacent to the filter arrangement (e.g., underneath). In other embodiments, the frass propulsion system may use other techniques to move frass in the frass receiving system, such as a conveyor belt system.

In some embodiments, the filter arrangement has different filter characteristics in different rearing receptacles 11, 12. The different filter characteristics may comprise different minimum and/or average pore sizes. For example, rearing receptacles (e.g., the second rearing receptacle 12 in Figures 1-3) later in the series than earlier receptacles (e.g., the first rearing receptacle 11 in Figures 1-3) may be associated with filter characteristics that allow relatively larger particles to pass into the frass receiving system. In the embodiment of Figures 1 and 2, the filter arrangement is provided by an array of holes in the base 8 of the rearing track 10. The rearing track 10 may for example comprise a laser machined metal or plastic sieve panel. In the portion 8A of the base 8 defining the first receptacle 11 an average pore size is smaller than in the portion 8B of the base 8 defining the second receptacle 12. Varying the filter characteristics as described above allows the filter arrangement to be better adapted to the various development stages of the larvae in the rearing system. As larvae get larger, pore sizes can be increased without risking larvae passing into the frass receiving system. This allows the pores to always be kept large enough to accommodate frass particles for all development stages of the larvae.

In some embodiments, as exemplified in Figures 1-3, the rearing system 2 comprises a sensor system 18. The sensor system 18 senses one or more characteristics of admixture in the series of rearing receptacles. The sensor system 18 may, for example, comprise an optical sensing arrangement such as a camera and/or a data processing system configured to process an output from the optical sensing arrangement. The data processing system may use any known image processing technique for this purpose, including machine learning techniques. The sensed characteristics where an optical sensing arrangement is used may comprise any characteristic that can be determined based on the visual appearance of the admixture. As explained below, such characteristics may include any one or more of the following: a stage of development of the larvae; an amount of feed relative to larvae in the admixture; a concentration of water present in the admixture; and/or a texture and/or viscosity of the admixture. Alternatively or additionally, the sensor system 18 may comprise a temperature sensor and the sensed characteristic of the admixture may comprise a temperature of the admixture.

In some embodiments, the sensor system 18 is configured to sense the one or more characteristics separately in different rearing receptacles. In some embodiments, the control of the gate system by the controller 4 is based at least in part on an output from the sensor system 18. For example, in some embodiments the sensor system is configured to determine one or more larval characteristics indicative of a stage of development of the larvae. The larval characteristics comprise one or more of the following: segment number, larval length, larval outline, larval shape; larval colour. The control of the gate system by the controller 4 may be based at least in part on the determined one or more larval characteristics. Thus, the controller 4 may be configured to monitor the development of the larvae and automatically initiate advancement of admixture through the series of rearing receptacles based on the stage of development of the larvae. For example, when it is determined that the larvae are getting too big for the rearing receptacle where they are currently present, the controller 4 may cause the admixture in that rearing receptacle to be advanced to a subsequent rearing receptacle in the series or to be expelled from the rearing system 2 if the determined larval development stage corresponds to a final larval development stage.

Alternatively or additionally, the sensor system 18 may be configured to detect anomalies in development of the larvae. The anomalies may be detected for example using one or more of the larval characteristics mentioned above and/or a variation with time of one or more of these larval characteristics. The anomalies may be indicative of a disease state and/or an unexpectedly slow or fast development rate. The controller 4 may initiate various actions in response to detection of such anomalies, such as outputting an audio, visual and/or data alert to a user, or interacting with the admixture to correct the anomaly. The interaction with the admixture may comprise adjusting a temperature of the admixture and/or adjusting a composition of the admixture (e.g., adding feed and/or water or changing a rate of addition of feed and/or water).

In some embodiments, as exemplified in Figures 1-3, the rearing system 2 comprises a feed supply system 24. The feed supply system 24 is configured to supply feed to one or more of the rearing receptacles 11, 12. Various techniques may be used to deliver feed. The feed supply system 24 may comprise an auger or conveyor feeding system. The feed may be provided, for example, in liquid form and sprayed over the top of the admixture. The feed supply system 24 may comprise any suitable combination of standard hardware elements, such as conduits, reservoirs, valves, pumps etc., necessary to achieve the desired functionality. Different types and/or quantities of feed may be delivered to different rearing receptacles to reflect the differing needs of larvae in the different rearing receptacles and/or different filter characteristics of any filter arrangement of a frass receiving system (e.g., to increase a particle size of feed in rearing receptacles where the filter characteristics are configured to allow passage of larger frass particles). The controller 4 controls the feed supply system 24 using an output from the sensor system 18. The output from the sensor system 18 used by the controller 4 to control the feed supply system may comprise information about an amount of feed relative to larvae in the admixture. The controller 4 may, for example, initiate delivery of a dose of feed when the sensor system 18 determines that the amount of feed relative to larvae has fallen below a predetermined minimum threshold value (e.g., when feed represents less than 25% of a visible portion of the admixture being imaged by the sensor system 18). The predetermined minimum threshold value may be the same or different in different rearing receptacles 11 , 12.

In some embodiments, as exemplified in Figures 1-3, the rearing system 2 comprises a water supply system 25. The water supply system 25 supplies water to one or more of the rearing receptacles 11, 12. The water supply system 25 may comprise any suitable combination of standard hardware elements, such as conduits, reservoirs, valves, pumps etc., necessary to achieve the desired functionality. The water supply system 25 is depicted schematically as a physical element separate from the feed supply system 24 but this need not be the case. The feed supply system 24 and water supply system 25 may share one or more physical elements. Elements of the feed supply, such as vitamins, yeast extracts, carrot or other vegetable extracts, etc., may be included (e.g., dissolved) in the water supply. A common outlet may be provided to provide at least a portion of the feed and the water, for example as a spray or mist. In some embodiments, the controller 4 is configured to control the water supply system 25 using an output from the sensor system 18. The output from the sensor system 18 used by the controller 4 to control the water supply system 25 may comprise information about a concentration of water present in the admixture or information about a texture and/or viscosity of the admixture. The controller 4 may, for example, initiate delivery of water to a rearing receptacle 11, 12 when the sensor system 18 determines that the concentration of water present in the admixture falls below a predetermined minimum threshold value. The predetermined minimum threshold value may be the same or different in different rearing receptacles 11, 12. Alternatively or additionally, the controller 4 may initiate delivery of water to a rearing receptacle 11, 12 when the sensor system 18 determines that the texture and/or viscosity of the admixture would benefit from addition of water, for example to improve flow properties of the admixture. The water supply system 25 may be configured to supply water at least partly as a mist to promote even distribution of the water over the admixture.

In some embodiments, as exemplified in Figures 1-3, the rearing system 2 may further comprise a temperature control system 26. The temperature control system 26 applies either or both of heating and cooling to the admixture in response to measurement of a temperature of the admixture, for example by the sensor system 18. Insect larvae are often poikilothermic and respond positively in terms of growth rate to temperatures between 26 °C and 32 °C. Automation of temperature can thus improve growth rate. In the case of yellow mealworm, for example, when adequate feed and water are provided, and constant 28 °C is maintained, a larval growth period of around 11 weeks can be expected. This may even be reduced if temperature is increased. Larval interaction within the growth substrate can change this development rate and so monitoring larval size can be a useful way to correct for rate anomalies to ensure optimal cost-effective development. With intelligent rearing systems these larval periods can be improved and thereby reduce cost.

As explained above, managing frass enables relatively high densities of larvae to be maintained within the rearing system 2. While larvae prefer to be reared in close proximity, friction-induced heating can lead to sub-optimally high temperatures in the absence of temperature control. Providing the ability to actively cool the admixture makes it possible to avoid excessively high temperatures, thereby allowing optimal development conditions to be maintained at all stages of development and in different ambient conditions. This temperature management ensures that optimum grow-out conditions are achieved.

The temperature control system 26 may for example comprise an infrared lamp and/or a heater configured to directly heat the body of the rearing receptacles 11, 12. For example, a heater may be provided that heats the base of the rearing receptacles 11, 12 as depicted schematically in Figure 3. In some embodiments, the temperature control system 26 applies a flow of air to heat or cool the admixture as desired. Where a frass propulsion system 16 is provided, as exemplified in Figure 1, the frass propulsion system 16 may form part of the temperature control system 26. By controlling the temperature and/or flow rate of air beneath the rearing receptacles, the frass propulsion system 16 can be controlled to control the temperature of the admixture in the rearing receptacles efficiently and flexibly.

Various different types of insect larvae may be used. The inventors have found that the approaches of the present disclosure work particularly efficiently with yellow mealworm, but larvae of other types of insect may be used, such as black soldier fly, lesser mealworm, and Morio worms.

The growth substrate of the admixture may in principle include any nutrients that will allow the insect larvae to develop to the target development stage. Normally, in the context of food or feed production insect larvae would be fed with feed materials that are considered as waste products in other contexts. However, as mentioned in the introductory part of the description, the inventors have recognized that the insect larvae may improve the nutritional quality of certain types of input feed product by eliminating certain nutritionally undesirable components such as antinutritional factors (ANFs). In this scenario, it becomes desirable to feed the insect larvae such higher quality feed because the food or feed provided by the insects themselves is of an even higher quality. This is the case for example when the insect larvae are fed material obtained from the soybean plant, most of which would normally be considered of too high quality to be given deliberately to insects in the context of food or feed production. In some implementations, therefore, a significant or majority portion of the feed content of the admixture may consist of soybean meal. The admixture may, for example, contain soybean meal at a concentration of at least 1%, optionally at least 5%, optionally at least 15%, optionally at least 25%, optionally at least 50%, optionally at least 75%, by weight of the admixture. Alternatively or additionally, the feed content of the admixture may comprise other components, such as soybean hulls, wheat bran, DDGS (dried distillers grains with solubles). Soybean hulls are a co-product of soybean processing and have been found to work particularly well as growth medium. The soybean hulls provide a growth medium having desirable flow properties and efficiently support growth of the insect larvae. The admixture may, for example, contain soybean hulls at a concentration of at least 1%, optionally at least 5%, optionally at least 15%, optionally at least 25%, optionally at least 50%, optionally at least 75%, by weight of the admixture.

In some embodiments, the growth substrate of the admixture is pre-treated to improve digestibility and/or nutritional value for the insect larvae. A major advantage of using unique feed substrates such as soy bean hulls, wheat bran and DDGS is that pretreatments of the product can be designed that are specific to the substrate. The pretreatment may, for example, comprise one or more of the following: use of one or more enzymes; a fermentation process. This contrasts with the use of varying mixtures of waste vegetable products for rearing insects for which a targeted pretreatment with enzymes would not be appropriate.

Plural instances of the rearing system 2 may be provided in a vertical stack to save space. Rearing systems 2 of the type depicted in Figures 1 and 2 lend themselves particularly well to this deployment mode.

Rearing systems 2 of the present disclosure may be particularly efficiently deployed in situations where co-products from manufacturing processes may be used as feed for the insect larvae. The rearing systems 2 may thus be provided on site or retrofitted to a range of existing manufacturing facilities. The rearing systems 2 may be used particularly effectively in manufacturing facilities for soybean processing, wherein the desirable soybean meal and/or soybean hulls will be readily available. The rearing systems 2 could also be used for example in manufacturing facilities configured for: beet pulp sugar production (where the co-product to be fed to the insect larvae would be beet pulp); potato processing (where the co-product to be fed to the insect larvae would be potato waste); distillery processing (where the co-product to be fed to the insect larvae would be distillery grains); and cereal processing (where the co-product to be fed to the insect larvae would be starch wastes). Deploying the rearing systems 2 in such contexts may also make use of waste heat in the main manufacturing facilities to reduce energy consumption by the rearing systems 2.

Claims

1. A rearing system for insect larvae, comprising: a series of rearing receptacles, each rearing receptacle configured to contain a larval admixture comprising growth substrate and either or both of insect eggs and insect larvae; a gate system configured to enable switching of each of at least a subset of the rearing receptacles between an open state in which the rearing receptacle allows admixture to flow out of the rearing receptacle and a closed state in which the rearing receptacle prevents admixture from flowing out of the rearing receptacle; and a controller configured to control at least the gate system to cause admixture to flow from one of the rearing receptacles in the series to a subsequent one of the rearing receptacles in the series.

2. The rearing system of claim 1, wherein the rearing receptacles have progressively larger sizes along the series to accommodate progressively later stages of growth of larvae in the admixture.

3. The rearing system of claim 1 or 2, wherein the controller is configured to control at least the gate system to expel admixture from the rearing system by causing admixture to flow out of a final rearing receptacle in the series.

4. The rearing system of claim 3, wherein the controller is configured to control at least the gate system to cause admixture to flow into the final rearing receptacle from a directly preceding rearing receptacle after the admixture in the final rearing receptacle has flowed out of the final rearing receptacle to make space available in the final rearing receptacle.

5. The rearing system of claim 3, wherein the series of rearing receptacles comprises three or more rearing receptacles and the controller is configured to control at least the gate system to cause admixture in each rearing receptacle prior to the final rearing receptacle to flow forward into a subsequent rearing receptacle in the series when space has been made available in the respective subsequent rearing receptacle by flow of admixture out of that rearing receptacle.

6. The rearing system of any preceding claim, further comprising an admixture propulsion system configured to drive flow of the admixture between different rearing receptacles along the series and/or out of the series of rearing receptacles.

7. The rearing system of claim 6, wherein the driving of the admixture comprises driving a flow of the admixture over a base of a rearing track defining the rearing receptacles.

8. The rearing system of claim 7, wherein the propulsion system comprises one or more pushing members and the propulsion system is configured to drive movement of each pushing member along the rearing track to push a respective portion of the admixture along the rearing track.

9. The rearing system of any preceding claim, further comprising a frass receiving system configured to receive frass from one or more of the rearing receptacles, the frass receiving system comprising a filter arrangement configured to allow frass to pass into the frass receiving system while blocking movement of other components of the admixture into the frass receiving system.

10. The rearing system of claim 9, wherein the frass receiving system is configured such that frass can pass from the one or more rearing receptacles to the frass receiving system under the action of gravity.

11. The rearing system of claim 9 or 10, wherein the filter arrangement is configured to have different filter characteristics in different rearing receptacles.

12. The rearing system of claim 11, wherein: the series of rearing receptacles comprises a first rearing receptacle and a second rearing receptacle, the first rearing receptacle being earlier in the series than the second rearing receptacle; and the different filter characteristics are such as to allow larger particles to pass into the frass receiving system from the second rearing receptacle compared to from the first rearing receptacle.

13. The rearing system of claim 11 or 12, wherein the different filter characteristics comprise different minimum or average pore sizes.

14. The rearing system of any of claims 9-13, further comprising a frass propulsion system configured to drive movement of frass in the frass receiving system.

15. The rearing system of claim 14, wherein the frass propulsion system is configured to generate a flow of gas to drive the movement of the frass.

16. The rearing system of claim 15, wherein the system is configured to control a temperature of admixture in one or more of the rearing receptacles by controlling one or more operating parameters of the frass propulsion system as a function of a measured temperature of the admixture in one or more of the rearing receptacles, wherein the one or more operating parameters includes one or more of the following: gas flow rate, gas heating power, gas cooling power.

17. The rearing system of any preceding claim, further comprising a sensor system configured to sense one or more characteristics of admixture in the series of rearing receptacles.

18. The rearing system of claim 17, wherein the sensor system is configured to sense the one or more characteristics separately in different rearing receptacles.

19. The rearing system of claim 17 or 18, wherein the sensor system is configured to determine one or more larval characteristics indicative of a stage of development of the larvae.

20. The rearing system of claim 19, wherein the larval characteristics comprise one or more of the following: segment number, larval length, larval outline, larval shape; larval colour.

21. The rearing system of claim 19 or 20, wherein the control of the gate system by the controller is based at least in part on the determined one or more larval characteristics.

22. The rearing system of any of claims 17-21, further comprising a feed supply system configured to supply feed to one or more of the rearing receptacles and the controller is configured to control the feed supply system using an output from the sensor system.

23. The rearing system of claim 22, wherein the output from the sensor system used by the controller to control the feed supply system comprises information about an amount of feed relative to larvae in the admixture.

24. The rearing system of any of claims 17-23, further comprising a water supply system configured to supply water to one or more of the rearing receptacles and the controller is configured to control the water supply system using an output from the sensor system.

25. The rearing system of claim 24, wherein the output from the sensor system used by the controller to control the water supply system comprises information about a concentration of water present in the admixture or information about a texture and/or viscosity of the admixture.

26. The rearing system of claim 24 or 25, wherein the water supply system is configured to supply water at least partly as a mist.

27. The rearing system of any preceding claim, further comprising a temperature control system configured to apply either or both of heating and cooling to the admixture in response to measurement of a temperature of the admixture.

28. The rearing system of any preceding claim, wherein the system comprises the admixture and the insect larvae include at least one or more of the following: yellow mealworm; black soldier fly, lesser mealworm, and Morio worms.

29. The rearing system of any preceding claim, wherein the system comprises the admixture and the admixture contains any products of soybean processing, such as soybean meal, soybean oil, and/or soybean hulls, at a concentration of at least 1% by weight of the admixture.

30. The rearing system of any preceding claim, wherein the system comprises the admixture and the admixture contains soybean meal at a concentration of at least 1% by weight of the admixture.

31. The rearing system of any preceding claim, wherein the system comprises the admixture and the admixture contains soybean hulls at a concentration of at least 1% by weight of the admixture.

32. The rearing system of any preceding claim, wherein the system comprises the admixture and the substrate has been pre-treated to improve digestibility and/or nutritional value and/or availability for the insect larvae, the pre-treatment optionally comprising one or more of the following: use of one or more enzymes; a fermentation process.

33. A method of rearing insect larvae, comprising: providing a series of rearing receptacles; providing larval admixture in at least a selected rearing receptacle in the series, the admixture comprising a growth substrate and either or both of insect eggs and insect larvae; using at least a gate system to cause the admixture to flow from the selected rearing receptacle into a subsequent rearing receptacle in the series by switching the selected rearing receptacle from a closed state in which the selected rearing receptacle prevents admixture from flowing out of the selected rearing receptacle to an open state in which the selected rearing receptacle allows admixture to flow out of the rearing receptacle.

34. The method of claim 33, wherein the rearing receptacles have progressively larger sizes along the series to accommodate progressively later stages of growth of larvae in the admixture.

35. The method of claim 34, wherein the admixture is caused to flow from the selected rearing receptacle to the subsequent rearing receptacle when the larvae in the admixture have reached a stage of growth where the larvae would benefit from more space.

36. The method of any of claims 33-35, wherein the admixture is caused to flow from the selected rearing receptacle to the subsequent rearing receptacle by driving a flow of the admixture over a base of a rearing track defining the rearing receptacles.

37. The method of any of claims 33-36, further comprising removing frass from the admixture in the selected rearing receptacle via a filter arrangement that blocks passage of other components of the admixture.

38. The method of claim 36, further comprising removing frass from the admixture in the selected rearing receptacle via a filter arrangement that blocks passage of other components of the admixture, wherein the filter arrangement is formed in the base of the rearing track.

39. The method of claim 37 or 38, wherein a temperature of the admixture is controlled by controlling a gas flow that entrains frass in a region adjacent to the filter arrangement.

40. The method of any of claims 33-39, wherein the admixture provided in the selected rearing receptacle contains soybean meal at a concentration of at least 1% by weight of the admixture.

41. The method of any of claims 33-40, wherein the admixture provided in the selected rearing receptacle contains soybean hulls at a concentration of at least 1% by weight of the admixture.

42. A method of producing a food product or a feed product, comprising: rearing insect larvae in an admixture until the insect larvae reach a target level of maturity; and collecting and processing the insect larvae that have reached the target level of maturity to produce the food product or the feed product, wherein the admixture comprises a growth substrate and the larvae, and: the admixture contains soybean meal at a concentration of at least 1% by weight of the admixture; and/or the admixture contains soybean hulls at a concentration of at least 1% by weight of the admixture.