Method for preparing a feed for farming insects

Abstract

The present invention relates to a method for preparing a feed for farming insects, comprising the steps of a) providing a substrate, b) supplementing one or more amino acid to the substrate of step a) to give a feed for farming insects having a crude protein content of more than 10 wt.-%, based on the total weight of the feed, and c) supplementing starch to the substrate of step a) or the feed of step b) to adjust the starch content in the substrate of step a) or the feed of step b) to give a feed for farming insects having a starch content of from 25 to 50 wt.-%, based on the total weight of the feed.

Description

[0001] Method for preparing a feed for farming insects

[0002] The present invention is on the field of farming insects. It relates to a method for preparing a feed for farming insects, a feed for farming insects, and the use of said feed for improving nitrogen utilization, for improving biomass of the insects, improving frass, reducing feed conversion rate, and / or reducing time-to-harvest and for reducing carbon footprint in the farming of insects.

[0003] Insects have been consumed by humans for thousands of years and are still a common food source in many cultures around the world. In recent years, there has been a growing interest in the potential of insects as a sustainable and nutritious food source for the future global food system. With the world population expected to reach almost 10 billion by 2050, it is expected that the demand for food will increase by 70%. This represents a significant challenge for the food industry because traditional livestock farming is resource-intensive and has a significant environmental impact. Insects, on the other hand, are highly efficient converters of biogenic materials into proteins and require significantly less land, water, and feed than traditional livestock. The black soldier fly (Hermetia illucens), mealworm (Tenebrio molitor), and cricket (Archeta domesticus) are the most relevant edible insect species for animals and human nutrition.

[0004] In aquacultures, insect products are used to feed fish such as salmon and shrimps. The insects are sustainable alternatives for traditional fish feed products, which often contain fishmeal and fish oil derived from wild-caught fish. By using insect protein meal as a feed source, aquaculture can reduce its reliance on wild-caught fish and promote sustainable fish farming practices.

[0005] In poultry farming, insects and insect-derived products are increasingly used to feed chickens, laying hens, ducks, geese, turkeys, and other birds. The larvae are a rich protein source and can support the growth and health of poultry. Additionally, insects can reduce the environmental impact of poultry farming by utilizing waste materials as feed: the insects are grown on waste materials and then are used as feed for poultry.

[0006] Insect meal is also used as a feed source for pets such as dogs, cats, and reptiles. The larvae are a sustainable alternative to traditional pet food, which often contains meat from factory-farmed animals. By using insects as a feed source, pet owners can reduce their pet’s environmental impact while providing a nutritious and sustainable protein source.

[0007] Overall, the use of insect protein in animal feed has the potential to revolutionize the animal feed industry. By utilizing a sustainable and nutritious protein source, insect production, especially the black soldier fly larvae production can reduce waste and promote sustainable animal farming practices.

[0008] Insect farming is a growing industry that offers a range of process operating models for producers. These models can vary depending in the type of insect being farmed, the intended use of the insects, the coproduced and up-cycled products, and the specific market demand. However, there are three major value streams that insect producers focus on: insect protein, insect oil, and trass (mix of not eaten substrate and insect excrement).

[0009] One process operating model might be focused on producing insect protein for animal feed. Insect protein is a high-quality source of nutrition for animals such as chickens, fish, and pigs. In this model, the insects are raised in large quantities and processed into a protein powder that can be added to animal feed. This model is particularly attractive to producers who are looking for a sustainable and cost-effective alternative to traditional protein sources. Insect protein is suitable to replace a large portion of soybean products in feed for terrestrial and aquatic livestock.

[0010] Other insect producers might focus on producing insect oil. This is a valuable nutrition source for both animals and humans. It is rich in essential fatty acids and can be used in a variety of products such as animal feed, cosmetics, and biofuels. In this model, the insects are raised in large quantities and processed to extract the oil. This approach is particularly attractive for up-cycled high-value products that can be sold to a range of markets.

[0011] Yet other insect producers might focus on insect frass, which is a mixture of non-eaten substrate (feed) and the excrements from the insects. This can serve as an excellent plant fertilizer as it is rich in plant nutrients such as nitrogen, phosphorous, and potassium. In this business model, the insects are raised in large quantities, and their frass is collected and sold as a fertilizer. The main focus here is to convert locally available biogenic side streams into valuable biofertilizer products, which can be a sustainable and environmentally friendly alternative to traditional fertilizers.

[0012] Each of the business models mentioned above has its own challenges. One key challenge is to produce the value stream that is specifically of utmost interest in a preferably resource- and cost-efficient way. As the three value streams (protein, oil, and frass) are always produced simultaneously, insect producers need to steer the production process in a way that improves efficiencies and maximizes the outputs of each value stream.

[0013] US 2017 / 251700 A1 discloses the feeding of high-protein feeds in insects such as honeybees and crickets. The level of proteins in these feeds is of 15-85%, such as 35-65% and 40-60%. The level of the carbohydrates is of 10-90%, such as 20-60%, 1-50% and 2-20%. Supplementary amino acids and lysine may be added.

[0014] KR 101836918 B1 discloses a feed for mealworms comprising added glutamic acid at a level of 5-50%, preferably 5-20% of the feed. Levels of 5, 10 and 15%, the rest being bran (a waste stream from food production) are disclosed in this document. As a result of the feeding, body weight and protein content of the mealworm is achieved.

[0015] CN 104381624 A discloses feed for silkworms comprising added amino acids at a level of 20-30 parts from a total of 51-75 parts, such as 2 kg from a total of 5.1 kg (39%). The feeding of that feed increases the growth of the silkworms and their numbers, thus their biomass. CN 116019183 A discloses high-protein feed for the feeding of larvae of black soldier flies, which comprises 15-20% crude protein. However, no amino acids are added to this feed.

[0016] KR 20220077244 A discloses an insect feed for black solider flies, crickets, beetles, and mealworms, comprising, e.g., 20% protein, which provides for an increased weight gain.

[0017] CN 1189089 discloses an insect feed comprising 30-35% crude protein for, e.g., housefly larvae.

[0018] Black soldier fly larvae (BSFL) are usually fed with biogenic side streams of the food and agricultural industry, which are therefore organic by- or waste-materials. Biogenic side streams include food waste, agricultural by-products and other organic materials that would otherwise be discarded. The use of, e.g., BSFL as a feed source has gained popularity due to their high protein content and their ability to convert waste into valuable nutrients. By using waste materials as feed, BSFL production can reduce the environmental impact of waste disposal while also producing a valuable source of animal feed. However, the composition of various feed materials varies greatly depending on the type, source, quality, and condition of the waste material. This can result in low performance and high nitrogen loss during BSFL production. A low nitrogen utilization efficiency is especially one of the biggest concerns in the industrial production of black solider fly larvae.

[0019] BSFL require sufficient feed for growing and developing, and as a result, the feed used in BSFL production is often high in nitrogen. However, studies have shown that BSFL have a low nitrogen utilization efficiency, meaning that a significant amount of the nitrogen in their feed is excreted as waste. Moreover, the excreted nitrogen is emitted to a high degree as gaseous ammonia and nitrous oxide and therefore, does not add to the quality of frass as plant fertilizer. Ammonia is a potent greenhouse gas that contributes to climate change, while nitrous oxide is a powerful greenhouse gas that is also a major contributor to ozone depletion. But even the use of biogenic waste material which is usually low in nitrogen is not a solution per se to overcome the nitrogen excretion problem. Nitrogen is an essential nutrient for the growth and development of BSFL, and low nitrogen content can result in reduced growth performance and increased health issues during larvae growth. Connected to that, feed substrates containing biogenic materials with low nitrogen concentrations also result in high nitrogen loss. Additionally, the high fiber content of many biogenic side streams can make it difficult for BSFL to digest and utilize the nutrients in the feed material. To address these challenges, it is important to carefully select and prepare the feed material for BSFL production. This can involve sorting and processing the waste materials to remove contaminants and improve the nutrient content. Additionally, pre-digestion techniques such as anaerobic digestion can help to increase the nutrient availability of the feed material for the insects. Nevertheless, there is often a protein nitrogen gap that needs to be balanced in BSFL nutrition. The addition of classical proteins such as soybean meal or rapeseed meal is not sustainable as these sources can be used for feeding animals and humans directly. Further, the addition of proteins per se might not meet the amino acid requirements of the black solider flies. Overdosing and inappropriate amino acid composition can result in impaired nitrogen utilization and thus, increased nitrogen emission, in accelerated pathogens growth, reduced BSFL growth performance or unstable production conditions. Another approach to addressing the protein gap in BSFL production is the use of genetic modification. Researchers have identified genes that are responsible for the production of specific amino acids. This can improve the nutritional quality of the larvae and reduce the need for additional protein sources. However, this approach faces both political and social hurdles. In many countries, genetically modified animals are not permitted by law. Especially in these countries, there is also a low or non-existent social acceptance for genetically modified animals.

[0020] Accordingly, there was still a need for an approach to successfully improve the nitrogen utilization of growing insect larvae.

[0021] It was found that this problem is solved by supplementing amino acids to a substrate and thus adjusting the amino acid profile in the substrate to give a feed for farming insects having the required amino acid content. It was further found that it needs a crude protein content of more than 10 wt.-%, based on the total weight of the feed, to achieve an increase in nitrogen utilization.

[0022] One object of the present invention is therefore a method for preparing a feed for farming insects, comprising the steps of a) providing a substrate, b) supplementing one or more amino acid to the substrate of step a) to give a feed for farming insects having a crude protein content of more than 10 wt.-%, based on the total weight of the feed, and c) supplementing starch to the substrate of step a) or the feed of step b) to adjust the starch content in the substrate of step a) or the feed of step b) to give a feed for farming insects having a starch content of from 25 to 50 wt.-%, based on the total weight of the feed.

[0023] Experiments proved that the insect final biomass, e.g., BSFL final biomass, was the lowest for a feed containing 9.8% crude protein (CP). By comparison, increasing the CP level in the feed to values of more than 10 wt.-%, based on the total weight of the feed, led to considerable increase in the BSFL final biomass. In particular CP levels of 12 wt.-% or more, led to considerable increase in BSFL final biomass as well as fat and crude protein in BSFL biomass.

[0024] In the context of the present invention the term crude protein is used as known to the person skilled in the art of livestock production and denotes the approximate amount of protein in feeds or foods that is calculated from the determined nitrogen content by multiplying by a factor of 6.25 derived from the average percentage of nitrogen in the feed / food proteins. Therefore, the term crude protein comprises all amino acids present in feed / food.

[0025] Said term may contain an error if the nitrogen is derived from non-protein material or from a protein of unusual composition. In analytics, there is also the sum of amino acids. However, this approach has the weakness that amino acids such as tyrosine or tryptophane are not routinely examined. Also, glutamine and asparagine are not analyzed individually but are later analyzed together with glutamic acid and aspartic acid by acid digestion. Therefore, preference is given to use term crude protein instead of sum of amino acids. In an embodiment of the method according to the present invention, in step b) the one or more amino acid is supplemented to the substrate to give a feed for farming insects having a crude protein content of at least 12 wt.-%, preferably 12.2% or more, based on the total weight of the feed.

[0026] In another embodiment of the method according to the present invention, in step b) the one or more amino acid is supplemented to the substrate to give a feed for farming insects having a crude protein content of from 12 to 25 wt.-%, based on the total weight of the feed.

[0027] Preferably, the crude protein content in the feed ranges from 12 to 20 wt.-%, from 12.2 to 19.3%, from 12 to 15 wt.-%, or from 12.2 to 15.5%, each based in the total weight of the feed.

[0028] It was also found that nitrogen emissions can be minimized by supplementing the substrate with starch. The additional presence of starch improves the utilization of the substrate, in particular of the amino acids, which results in a minimized emission of nitrogen and a considerably reduced nitrogen loss in the raised insects.

[0029] Preferably, the starch content in the feed ranges from 26 to 49 wt.-%, 27 to 48 wt.-%, 28 to 47 wt.-%, 29 to 46 wt.-%, 30 to 45 wt.-%, or 25 to 45 wt.-%, 25 to 40 wt.-%, 25 to 35 wt.-%, or 26 to 32 wt.-%, each based on the total weight of the feed. Other preferred starch contents range from 30 to 50 wt.-%, 30 to 49 wt.-%, 30 to 48 wt.-%, 30 to 47 wt.-%, 30 to 46 wt.-%, or 30 to 45 wt.-%, each based on the total weight of the feed.

[0030] In the context of the present invention the term substrate is used to denote the material on or in which an insect lives and grows. The present invention addresses the adjustment of crude protein content in the substrate to give a feed for farming insects having a specific crude protein content. Hence, a typical substrate for use in the method according to the present invention is therefore a substrate with a low crude protein content or a crude protein deficiency, and specifically, containing less than or even significantly less than 10 wt.-% of crude proteins, based on the total weight of the substrate, or even no crude protein at all. On the other hand, a typical substrate for use in the method according to the present invention provides other beneficial benefits, such as a certain sugar, mineral or fiber content, which makes it a useful starting point for preparing a feed for farming insects. In view of these aspects, the term substrate is not limited to specific substrates in the context of the present invention.

[0031] Nevertheless, it is preferred that a substrate comprises or consists of straws, e.g., wheat straw, rice straw, barley straw, oat stray, rye straw, maize stover, sorghum stover, cotton stalks, sunflower stalks, soybean stalks, peanut shells, corn cobs, miscanthus, switchgrass, bamboo, wheat bran, rice bran, barley bran, oat bran, rye bran, sugarcane bagasse, olive mill waste, palm bushels, palm kernel meal, wood materials, e.g., wood whips, sawdust, bark, wood shavings, wood pellets, forest residues, hardwood, softwood, pine, spruce, fir, oak, beech, birch, poplar, eucalyptus, willow, acacia, chestnut, walnut, cherry, maple, ash, elm, mahogany, teak, bamboo, animal by-products, e.g., fish waste, poultry litter, blood meal, feather meal, meat and bone meal, poultry meal, waste streams from food production, e.g., food waste, brewery waste, distillery waste, fruit and vegetable waste, e.g., pomace such as apple pomace, coffee waste, cocoa waste, olive mill waste, cheese whey, molasses, corn steep liquor, or combinations of any of these.

[0032] In one embodiment of the method according to the present invention the substrate comprises or consists of straws, peanut shells, corn cubs, miscanthus, switchgrass, bamboo, bran, bagasse, olive mill waste, palm bushel, and palm kernel meal; woods materials; animal by-products; and waste streams from food and / or feed production.

[0033] In the context of the present invention the term feed is used to denote the material on or in which an insect lives and grows, and which, in contrast to the substrate, contains more than 10 wt.-% of crude protein, based on the total weight of the feed. Therefore, the feed is also not limited to specific substrates in the context of the present invention. Rather, a feed in the context of the present invention comprises any of the preferred substrates mentioned above and contains more than 10 wt.-% of crude protein, based on the total weight of the feed.

[0034] In the context of the present invention the term amino acid is used as known to the person skilled in the art and denotes any organic compound that contains both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 21 alpha-amino acids or proteinogenic amino acid incorporated into proteins. Only these 21 appear in the genetic code of all life. They can be further distinguished into essential amino acid and non-essential amino acids.

[0035] In the context of the present invention the term essential amino acid, synonymous with indispensable amino acid, is used to denote an amino acid that cannot be synthesized by an insect at all or at least fast enough to supply its demand and must therefore come from the feed or diet.

[0036] In contrast, the term non-essential amino acid is used in the context of the present invention to denote an amino acid that can be produced by the insect itself and therefore only have to be ingested to a limited extent with the feed or diet.

[0037] Therefore, the one or more amino acid can be an essential amino acid, e.g., arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophane, valine, and tyrosine, wherein the term essential amino acid comprises both stereoisomers, i.e., the L- and the D-form, a salt of an essential amino acid, a derivative of an essential amino acid, e.g., methionyl methionine (dipeptide of methionine), 2- hydroxy-4-(methylthio)-butanoic acid also known as methionine hydroxy analogue, a salt of a derivative of an essential amino acid a non-essential amino acid, e.g., alanine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, and serine, wherein the term non-essential amino acid comprises both stereoisomers, i.e., the L- and the D-form, a salt of a non-essential amino acid, a derivative of a non-essential amino acid, a salt of a derivative of a non-essential amino acid or combination of any these.

[0038] In a further embodiment of the method according to the present invention the one or more amino acid comprises or consists of an essential amino acid, a salt of an essential amino acid, a non-essential amino acid, a salt of a non-essential amino acid, a derivative of any of these, or a combination of any of these.

[0039] In an embodiment of the method according to the present invention the one or more amino acids comprises or consists of at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17 or 18 amino acids, salts thereof, derivatives of any of these, or a combination of any of these.

[0040] In another embodiment of the method according to the present invention the one or more amino acids comprises or consists of all essential amino acids, salts thereof, derivatives of any of these, or a combination of any of these.

[0041] In a further embodiment of the method according to the present invention the one or more amino acids comprises or consists of all essential amino acids and the non-essential amino acids alanine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, and serine, salts thereof, derivatives of any of these, or a combination of any of these.

[0042] Preferably, the one or more amino acids comprises the amino acids comprises or consists of lysine, methionine, cysteine, threonine, arginine, isoleucine, leucine, valine, histidine, and phenylalanine, salts thereof, derivatives of any of these, or a combination of any of these.

[0043] In particular, the one or more amino acids comprises the amino acids comprises or consists of lysine, methionine, cysteine, threonine, tryptophane, arginine, isoleucine, leucine, valine, histidine, phenylalanine, tyrosine, glycine, serine, proline, alanine, asparagine, and glutamine, salts thereof, derivatives of any of these, or a combination of any of these.

[0044] In the context of the present invention the term insect is used to denote pancrustacean hexapod invertebrates of the class insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax, and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Their blood is not totally contained in vessels; some circulates in an open cavity known as the haemocoel. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between six and ten million; potentially over 90% of the animal life forms on earth are insects. There is a huge variety of insects. Thus, in the context of the present invention the term insects is not subject to any limitation regarding specific insects.

[0045] Rather, in the context of the present invention the insects can be flies (Diptera) and corresponding larvae, e.g., black soldier fly (Hermetia illucens), house flies (Musca domestica), blow flies (Calliphoridae), fruit flies (Drosophila melanogaster), stable flies (Stomoxys calcitrans); beetles (Coleoptera) and corresponding larvae, e.g., mealworm (Tenebrio molitor), lesser mealworm (Alphitobius diaperin us), darkling beetle (Tenebrionidae), superworm (Zophobas morio), buffalo beetles (Alphitobius laevigatus); crickets, e.g., house cricket (Acheta domesticus), field cricket (Gryllus assimilis), banded cricket (Gryllodes sigillatus), migratory locust (Locusta migratoria), desert locust (Schistocerca gregaria); other insects and corresponding larvae, e.g., silkworm (Bombyx mori), waxworm (Galleria mellonella), silkmoth (Antheraea pernyi), ant (Atta laevigata), cockroach (Blaptica dubia), termite (Macrotermes bellicosus), moth (Bombyx mandarina), ladybug (Harmonia axyridis), shield bug (Halys dentatus), cicada (Cryptotympana atrata), dragonfly (Pantala flavescens), water bug (Lethocerus indicus), weevil (Rhynchophorus ferrugineus), and aphid (Myzus persicae), butterflies (Lepidoptera) , or combinations of any of these.

[0046] In yet a further embodiment of the method according to the present invention, the insects comprise or consist of flies and corresponding larvae, beetles and corresponding larvae, crickets and corresponding larvae, locusts and corresponding larvae, worms and corresponding larvae, moths and corresponding larvae, ants and corresponding larvae, cockroaches and corresponding larvae, termites and corresponding larvae, cicada and corresponding larvae, dragonflies and corresponding larvae, water bugs and corresponding larvae, weevils and corresponding larvae, and aphids and corresponding larvae, butterflies and corresponding larvae, or combinations of any of these.

[0047] The method according to the present invention allows the preparation of a feed which provides farming insects with the required amount of amino acids for improving their growth and their final biomass.

[0048] Another object of the present invention is therefore a feed for farming insects having a crude protein content of more than 10 wt.-%, based on the total weight of the feed, wherein the feed has a starch content of from 25 to 50 wt.-%, based on the total weight of the feed.

[0049] In an embodiment of the feed for farming insects according to the present invention said feed has a crude protein content of at least 12 wt.-%, based on the total weight of the feed. In another embodiment of the feed for farming insects according to the present invention said feed has a crude protein content of from 12 to 30 wt.-%, based on the total weight of the feed.

[0050] In a further embodiment of the feed for farming insects according to the present invention said feed has a starch content of from 25 to 45 wt.-%, based on the total weight of the feed.

[0051] Preferably, the starch content in the feed ranges from 26 to 49 wt.-%, 27 to 48 wt.-%, 28 to 47 wt.-%, 29 to 46 wt.-%, 30 to 45 wt.-%, or 25 to 45 wt.-%, 25 to 40 wt.-%, 25 to 35 wt.-%, or 26 to 32 wt.-%, each based on the total weight of the feed. Other preferred starch contents range from 30 to 50 wt.-%, 30 to 49 wt.-%, 30 to 48 wt.-%, 30 to 47 wt.-%, 30 to 46 wt.-%, or 30 to 45 wt.-%, each based on the total weight of the feed.

[0052] The feed according to the present invention and / or the feed obtained by the method according to the present allows for improving nitrogen utilization in the farming of insects. Experiments have shown that the use of the feed according to the present invention and / or the feed obtained by the method according to the present increase(s) nitrogen utilization considerably. In particular, a feed having a crude protein content of from 12 and 15 wt.-%, or 12.2 to 14.5 wt.-%, based on the total weight of the feed, achieves a considerable increase in nitrogen utilization, specifically nitrogen utilization of amino acids. This also indicates an improvement in the crude protein content in insect final biomass.

[0053] A further object of the present invention is therefore the use of the feed for farming insects according to the present invention for improving nitrogen utilization in the farming of insects.

[0054] The improved nitrogen utilization in the farming of insects also has a positive effect on the biomass of the insect. In detail, the use of the feed according to the present invention gives an increase in final biomass of the farmed insects, compared to the same amount of feed not according to the present invention. In other words, the feed according to the present invention is more efficient in insect farming than a feed not according to the present invention. As a consequence, not only the time-to-harvest for insect farming is reduced but also the feed conversion ratio. Another benefit of the improved nitrogen utilization is the reduced loss of nitrogen to be found in insects frass, which results in an improved frass quality.

[0055] Yet another object of the present invention is therefore the use of the feed for farming insects according to the present invention for improving biomass of the insects, improving frass quality, reducing feed conversion rate, and / or reducing time-to-harvest in the farming of insects.

[0056] In the context of the present invention the term feed conversion ratio (FCR) is used to denote the ratio of the feed to the insect biomass, given as kg feed per kg insect biomass. Hence, lower FCR values indicate higher conversion efficiency of the feed.

[0057] The production of feed is typically accompanied by carbon dioxide release, resulting either from the chemical production of feed ingredients, or from the machines used for harvesting or processing the feed raw materials. Consequently, the more efficient the feed the lower is the released volume of carbon dioxide. Yet a further object of the present invention is therefore the use of the feed according to the present invention for reducing carbon dioxide in the farming of insects.

[0058] In the context of the present invention the term carbon footprint (or greenhouse gas footprint) is used to denote a measure of the total amount of carbon dioxide emissions that are directly and indirectly caused by activities or occur during the life stages of a product.

[0059] In an embodiment of all, each or a single of the uses according to the present invention the insects comprise or consist of flies and corresponding larvae, beetles and corresponding larvae, crickets and corresponding larvae, locusts and corresponding larvae, worms and corresponding larvae, moths and corresponding larvae, ants and corresponding larvae, cockroaches and corresponding larvae, termites and corresponding larvae, cicada and corresponding larvae, dragonflies and corresponding larvae, water bugs and corresponding larvae, weevils and corresponding larvae, aphids and corresponding larvae, butterflies and corresponding larvae, or combinations of any of these.

[0060] Examples:

[0061] 1 . Example: Refining black soldier fly larvae substrates with amino acid for improving production key performance indictors

[0062] A first experiment was done with black soldier fly larvae (BSFL, Hermetia illucens) grown on substrates. In detail, BSFL were grown on pure depectinized apple pomace (DAP) (treatment 1), DAP (70%) supplemented with starch (26%) (treatment 2), DAP (84%) supplemented with an amino acid mix (12%) (treatment 3), and DAP (50%) supplemented with starch (32%) and an amino acid mix (14%) (treatment 4).

[0063] The purpose of this experiment was to find out whether refining a substrate based on DAP with amino acids and / or starch would allow for better BSFL performance. Prior to BSFL rearing, the feed was soaked with water to achieve about 60±10% moisture. Each treatment was replicated 5 times and 150 mg of Hermetia illucens eggs were placed on the feed in boxes (19.5 x 16.5 x 9.5 cm) at a constant temperature of 27 °C.

[0064] After hatch, BSFL were fed in 48 h-intervals which means that additional material was added in relation to the body mass development. In same intervals, 25 larvae per box were weighed. Growth trial was terminated when at least 50% of larvae per box achieved prepupae stage. Feeds, larvae, and frass were analyzed for crude nutrients and amino acids.

[0065] Table 1 : Details on the feed compositions (air dry) in the first experiment

[0066] * calculated

[0067] BSFL grown on pure DAP achieved the lowest body weight and biomass, although the highest number of larvae found in the biomass (see Table 2). Forthis low performance, BSFL showed poorest feed conversion resulting in the flattest growth curve. They needed 82 days to achieve >50% prepupae stage.

[0068] Table 2: Performance results of BSFL grown on various feeds 1DAP: depectinized apple pomace; AA: amino acids2feed to biomass ratio

[0069] Statistics: Different superscripts (a b) within a row indicate significant differences with p<0.05, Tukey test; * tendency between DAP and DAP + starch, p = 0.10; no stats for days to prepupae, BSFL weight, and larvae in biomass All other treatments resulted in a better productivity. While addition of starch almost doubled individual weights, final biomass was even lower. However, both age to harvest and feed conversion were numerically improved.

[0070] With the addition of amino acids, and particularly when combined with starch, body weights and biomass production (p<0.05) was maximized and both harvest age and feed age were minimized (p<0.05).

[0071] BSFL grown on DAP only had lowest dry matter (DM) content, while addition of starch, amino acids or both increased DM significantly (p<0.05) and considerably (see results in Table 2). However, addition of starch particularly increased fat content and yield (p<0.05), while addition of amino acids increased crude protein (CP) content and yield (p<0.05). The highest yields were measured for a feed based on DAP and supplemented with starch and amino acids because of the highest biomass yield.

[0072] Nitrogen (N) conversion was highest with addition of both starch and amino acids. Although it cannot be assumed that N provided with the feed was not entirely ingested, a 30.8% N-conversion suggests potential for improvement. It was also found that BSFL were not able to increase N-conversion at very low crude protein supply with pure DAP or DAP in combination with starch only.

[0073] Table 3: Nutrient composition and yield of BSFL grown on different feeds

[0074] 1DAP: depectinized apple pomace, AA: amino acids;2DM: dry matter; CP: crude protein, one pooled sample per treatment, no statistics; N-conversion: nitrogen gained / nitrogen offered with feed;

[0075] Statistics: Different superscripts (a b) within a row indicate significant differences with p<0.05, Tukey test; * tendency between DAP and DAP + AA, p = 0.07

[0076] Multiple regression of data suggest impact of starch or sum of amino acids on fat yield. Accordingly, each additional % of starch would increase fat yield by 0.041g and each additional % of sum of amino acids would increase fat yield by 0.039 g (Fat in biomass (g) = -0.155 (p>0.05) + 0.041 x starch content (p<0.01) + 0.039 x sum of amino acids (p<0.01), r2: 0.87). Regarding protein yield, starch had no significant effect, but yield increased by 0.25 g per % sum of amino acids (CP in biomass (g) = 0.49 (p>0.05) + 0.25 x sum of amino acids (p<0.01), r2: 0.60). Summarizing, the findings of the first experiment are

[0077] • addition of amino acids and / or starch improve growth performance of BSFL; however, starch stimulate rather the fat deposition, while amino acids stimulate protein yield,

[0078] • BSFL are capable to efficiently utilize free amino acids for growth,

[0079] • while biomass output could be optimized, addition of amino acids and starch also optimized time to harvest as well as conversion efficacy,

[0080] • addition of amino acids minimized feed conversion to biomass suggesting that BSFL do have a requirement for amino acids, and

[0081] • amino acids supplementation and starch addition are suitable strategies to optimize BSFL production process.

[0082] 2. Example: Optimizing growth and nitrogen utilization of black solider fly larvae with amino acid supplementation

[0083] The first experiment demonstrated that adding either starch or amino acids or both to depectinized apple pomace substantially affected key production indicators of BSFL. However, although the addition of amino acids (AA) significantly improved BSFL performance and although most of the dietary nitrogen (N) was supplied as highly available AA, conversion of feed-N into biomass-N was low. This suggests an unsatisfactory use of expensive and valuable ingredients.

[0084] Therefore, a second experiment with BSFL was done in which the degree of supplementation of amino acids in the feed was varied resulting in different graded crude protein levels in the feed.

[0085] This experiment was based on the most successful treatment of the first experiment in which DAP with a starch level of 32.3 % and an amino acid-mix level of 14% gave the best performance. Therefore, all feeds in the second experiment contained 32.3% starch and the amino acid-mix level was increased at the expense of DAP, but the ratios among the amino acids were maintained. Thus, the crude protein level in the 5 treatments varied as follows:

[0086] • Treatment 1 : 19.3% CP and 49.1 % DAP

[0087] • Treatment 2: 16.9% CP and 51 .6% DAP

[0088] • Treatment 3: 14.5% CP and 54.1 % DAP

[0089] • Treatment 4: 12.2% CP and 56.6% DAP

[0090] • Treatment 5: 9.8% CP and 59.1 % DAP

[0091] Prior to BSFL rearing, the feed was soaked with water to achieve about 60±10% moisture. Each treatment was replicated 5 times and 100 Hermetia illucens larvae were placed on the feed in boxes (16 x 10 x 7 cm) at a constant temperature of 27 °C. In 4 day-intervals, 25 larvae per box were weighed. The growth trial was terminated when at least 50% of larvae per box achieved prepupae stage. Feeds, larvae, and trass were analyzed for crude nutrients and amino acids.

[0092] Table 4: Details on the feed compositions (air dry) in the second experiment

[0093] 1CP: crude protein; * calculated

[0094] After day 16, BSFL weight decreased and at termination of the study, the individual weights did not statistically differ anymore. However, the final biomass tended to be the lowest for feed with 9.8% AA (table 5, p<0.10) which is attributable to the slightly lower survival. At the same time, the feed conversion was significantly worse in treatment 5 (p<0.05).

[0095] Table 5: Performance results of BSFL grown on various feeds with graded levels of balanced crude protein

[0096] 1CP: crude protein;2feed to biomass ratio;

[0097] Statistics: Different superscripts (a b) within a row indicate significant differences with p<0.05; different superscripts (A B) within a row indicate significant differences with p<0.10, Tukey test

[0098] Graded dietary CP levels also affected BSFL nutrient composition. The lowest CP supply in treatment 5 resulted in lowest DM and fat content (in DM), while CP content (in DM) was highest. However, converting biomass gain and nutrient levels into fat and CP yield revealed highest CP yield with treatments 1 and 4, i.e., with feeds having an CP level of 19.3% and 12.2%. Although not clearly differentiated by statistics, fat yield seemed to gradually decrease with reducing CP levels in the feed - indeed with largest reduction in treatment 5 (9.8% CP). This may indicate that reduction of CP reduces energy being available to BSFL (the other energy sources starch and fat were not different among the treatments). Thus, BSFL are capable to use CP as energy source.

[0099] Table 6: nutrient composition and yield of BSFL grown on feeds with varying graded CP levels

[0100] 1CP: crude protein;2DM: dry matter; one pooled sample pertreatment, no statistics; N-conversion: nitrogen gained / nitrogen offered with feed;

[0101] Statistics: Different superscripts (a b) within a row indicate significant differences with p<0.05, Tukey test;

[0102] CP levels in feeds significantly affected N-conversion (see table 7). Accordingly, it maximized with 40.8% at 12.2% CP in feed. N-Conversion gradually improved with gradual dietary CP reduction. Compared to the results of the first experiment, N-conversion could be improved with reduction of the entire AA profile.

[0103] Summarizing, the findings of the second experiment are

[0104] • gradual reduction of an entire amino acid profile resulted in gradually reduced crude protein levels in the feeds for BSFL,

[0105] • at low CP levels, particularly below a CP level of 12%, performance of BSFL suffered in any respect, and • BSFL can utilize amino acids as energy source for fat deposition and dietary crude protein levels below 12% considerably reduced fat content in BSFL.

[0106] It is concluded that crude protein level can be reduced to 12% in feeds without negative effect on production key performance indicators while nitrogen conversion can be maximized at a crude protein level of 12% in the feed. This finding allows for optimized cost-effectiveness of BSFL production using feeds based on materials with low nutritional value.

[0107] 3. Example: Digestion and utilization of amino acids and nitrogen by black solider fly larvae

[0108] The second experiment demonstrated that crude protein level in a feed can be reduced to 12% without negative effect on key performance indicators while nitrogen (N) conversion was maximized. A value of about 41 % was the highest N-conversion (N retained in BSFL biomass relative to N offered with feed) achieved, which appears low compared to N-utilization of about 60% in broiler production (retained N relative to ingested N). Indeed, not all N of the feed might have been ingested by BSFL which is to the disadvantage of the calculated N-conversion figure. Therefore, a further trial was done to examine the digestibility and utilization of amino acids (AA) and N to have a better understanding for process optimization.

[0109] This trial was based on the most successful treatment of the first experiment in which DAP with a starch level of 32.3% and an amino acid-mix level of 14% gave the best performance. Therefore, all feeds in the second experiment also contained 32.3% starch and the amino acid-mix level was increased at the expense of DAP but the ratios among the amino acids were maintained. The ratios among the amino acids were always maintained. Thus, the crude protein level in the 5 treatments varied as follows:

[0110] • Treatment 1 : 19.3% CP and 49.1 % DAP

[0111] • Treatment 2: 16.9% CP and 51 .6% DAP

[0112] • Treatment 3: 14.5% CP and 54.1 % DAP

[0113] • Treatment 4: 12.2% CP and 56.6% DAP

[0114] • Treatment 5: 9.8% CP and 59.1 % DAP

[0115] Prior to BSFL rearing, the feed was soaked with water to achieve about 60±10% moisture. Each treatment was replicated 5 times and 100 Hermetia illucens larvae were placed on the feed in boxes (16 x 10 x 7 cm) at a constant temperature of 27 °C.

[0116] In 4 day-intervals 25 larvae per box were weighed together. The growth trial was terminated when at least 50% of larvae per box achieved prepupae stage. Feeds, larvae, and frass were analyzed for crude nutrients and amino acids.

[0117] Table 4 above summarizes the details on the feed compositions (air dry) in the third experiment. According to international conventions, CP represents N x 6.25. However, this factor is rarely correct. Only 56.2 to 68.3% of the nitrogen in BSFL biomass was explained by AA (see Table 7). This is in contrast to other materials of animal origin (e.g., 85% for meat and bone meal or fish meal) as well as for the feeds offered in treatments 1 to 5 (87.4%, 85.2%, 86.6%, 84.2%, 84.9%). Therefore, a relatively high proportion of retained N was non-protein nitrogen (NPN) and very likely deposited in the form of chitin containing 6.9% N. Therefore, it is assumed that a certain percentage of AA ingested by BSFL with feed is converted into chitin. Interestingly, the lower the biomass performance, the lower the percentage of N explained by AA suggesting reduced true protein deposition. These relative differences would also impact nutritional value of BSFL products for animal nutrition as chitin has limited value. The results summarized in Table 7 indicate highest conversion of feed AA into biomass AA in the treatment with 12.2% CP (treatment 4). However, this number also suggests that 69% (treatment 4) to 80% (treatment 1) of AA offered with feed were not utilized for protein deposition indicating an inefficient conversion.

[0118] Table 7: Deposition of amino acids in BFFL biomass when grown on various feeds with varying levels of balanced crude protein

[0119] 1CP: crude protein;2OS: original substrate, as is; CP and amino acid analyses of pooled sample per treatment, no statistics;3N-conversion: nitrogen gained / nitrogen offered with feed; Statistics: Different superscripts (a b) within a row indicate significant differences with p<0.05, Tukey test;

[0120] Table 8 shows essential AA quantities analyzed in frass and AA quantities originating from DAP. Interestingly, no free AA could be detected in frass which is interesting insofar as about 57 % (treatment 5) to 84 % (treatment 1) of overall AA in the feeds were supplemented free AA. Indeed, there is a fairly good agreement between AA quantities in frass and those originating from DAP. It is assumed that BSFL completely consumed the free AA which implies complete digestion of free AA. This is in line with free AA digestibility of farm animals and applies also for all non-essential AA. Therefore, supplemental AA can be considered as valuable and highly available nutrients for BSFL production. However, degradation of feed AA by microbiota and / or incorporation into microbiota protein cannot be fully excluded. Therefore, although BSFL were not able to efficiently unlock AA from DAP, respective digestibility was likely higher than zero. Pretreatment with fungi might help unlocking nutrients and increasing digestibility in this context. Table 8: Quantified essential amino acids in frass and originating from depectinized apple pomace in feed

[0121] 1CP: crude protein; DAP: depectinized apple pomace As discussed earlier only 20% to 31 % of AA supplied in feed were recovered in BSFL biomass (Tables 7 and 9). However, digestibility of AA was high. Obviously, a considerable portion of absorbed AA was not incorporated in body protein. While some of the N was transformed into chitin, there is still a gap in mass balances suggesting degradation of N and AA (Table 9). Comparing N disappearance with AA disappearance, the numbers for AA are basically higher. On one hand AA-N has partly been deposited as chitin and on the other hand has been excreted after degradation resulting generally in more favorable conversion factors (Table 9). Therefore, N-conversion might be a reasonable number for N-balances but not for assessing AA utilization. However, while N-conversion could be maximized to 40.8% in treatment 4, most of the “disappeared” N was deposited and the losses which likely disappeared as ammonia were small and were minimized in treatment 5. At least, a rather large proportion was still in frass which would contribute to fertilizing quality.

[0122] Table 9: Various conversion factors for nitrogen and sum of amino acids

[0123] 1CP: crude protein; N: nitrogen; AA: amino acids2disappearance from feed: (feed-frass)Zfeed; conversion: biomass / feed; deposition of disappeared: biomassZ(feed-frass); losses: (feed-frass-biomass)Zfeed

[0124] Statistics: Different superscripts (a b c d) within row indicate significant differences with p<0.05; Tukey test

[0125] With respect to AA the conversion factors look different. Disappearance from feed was rather high while deposition (% of feed) was rather low and was maximized in treatment 4. The same treatment showed highest deposition of disappeared AA. This number might serve as intermediate utilization which, together with digestibility, indicates the availability of AA for deposition (digestibility x utilization = availability).

[0126] Overall, AA losses (recovered neither in biomass nor in frass) gradually declined with CP content in feed. This demonstrates that composition, source of AA as well as their digestibility and utilization offer opportunities to optimize feed and productivity of BSFL production.

[0127] Numbers in Table 9 are based on sum of AA. However, the various conversion factors vary greatly between individual AA. With respect to the most successful diet (12.2 % CP, treatment 4) valine had highest utilization (70% of disappeared) whereas cysteine had the lowest (33% of disappeared). Such analyses may allow for identifying most limiting AA indicated by the highest value although it should be assumed, e.g., in the case of cysteine, that AA are required for maintenance purposes and are, thus, transformed but not deposited which in turn would lower conversion numbers.

[0128] Summarizing, the findings of the second experiment are

[0129] • supplemental amino acids are highly, if not 100%, digestible by BSFL,

[0130] • nitrogen and amino acid deposition calculations are affected by chitin formation and should therefore be distinguished for efficiency evaluations.

[0131] • reduction of CP to 9.8 % in feed reduced N-losses to minimum - however, performance was maximized at 12.2% CP. Amino acid losses amounted to 33 - 37% in these treatments, and

[0132] • utilization of sum of amino acids for deposition maximized with 12.2 % CP in feed but there is large variation between amino acids allowing for identification of most limiting amino acid.

Claims

Patent claims1 . A method for preparing a feed for farming insects, comprising the steps of a) providing a substrate, b) supplementing one or more amino acids to the substrate of step a) to give a feed for farming insects having a crude protein content of more than 10 wt.-%, based on the total weight of the feed, and c) supplementing starch to the substrate of step a) or the feed of step b) to adjust the starch content in the substrate of step a) or the feed of step b) to give a feed for farming insects having a starch content of from 25 to 50 wt.-%, based on the total weight of the feed.

2. The method according to claim 1 , wherein in step b) the one or more amino acids is supplemented to the substrate to give a feed for farming insects having a crude protein content of at least 12 wt.-%, based on the total weight of the feed.

3. The method according to claim 1 or 2, wherein in step b) the one or more amino acids is supplemented to the substrate to give a feed for farming insects having a crude protein content of from 12 to 30 wt.-%, based on the total weight of the feed.

4. The method according to any of claims 1 to 3, wherein the feed has a starch content of from 25 to 45 wt.-%, based on the total weight of the feed.

5. The method according to any of claims 1 to 4, wherein the substrate comprises or consists of straws, peanut shells, corn cubs, miscanthus, switchgrass, bamboo, bran, bagasse, olive mill waste, palm bushel, and palm kernel meal; woods materials; animal by-products; and waste streams from food and / or feed production.

6. The method according to any of claims 1 to 5, wherein the one or more amino acid comprises or consists of an essential amino acid, a salt of an essential amino acid, a non-essential amino acid, a salt of a non-essential amino acid, a derivative of any of these, or a combination of any of these.

7. The method according to any of claims 1 to 6, wherein the insects comprise or consist of flies and corresponding larvae, beetles and corresponding larvae, crickets and corresponding larvae, locusts and corresponding larvae, worms and corresponding larvae, moths and corresponding larvae, ants and corresponding larvae, cockroaches and corresponding larvae, termites and corresponding larvae, cicada and corresponding larvae, dragonflies and corresponding larvae, water bugs and corresponding larvae, weevils and corresponding larvae, and aphids and corresponding larvae, butterflies and corresponding larvae, or combinations of any of these.

8. A feed for farming insects having a crude protein content of more than 10 wt.-%, based on the total weight of the feed, wherein the feed has a starch content of from 25 to 50 wt.-%, based on the total weight of the feed.

9. The feed for farming insects according to claim 8, wherein the feed has a crude protein content of at least 12 wt.-%, based on the total weight of the feed.

10. The feed for farming insects according to claim 8 or 9, wherein the feed has a crude protein content of from 12 to 30 wt.-%, based on the total weight of the feed.

11. The feed for farming insects according to any of claims 8 to 10, wherein the feed has a starch content of from 25 to 45 wt.-%, based on the total weight of the feed.

12. Use of the feed for farming insects according to any of claims 8 to 11 for improving nitrogen utilization in the farming of insects.

13. Use of the feed for farming insects according to any of claims 8 to 11 for improving biomass of the insects, improving frass quality, reducing feed conversion rate, and / or reducing time- to-harvest in the farming of insects.

14. Use of the feed for farming insects according to any of claims 8 to 11 for reducing carbon footprint in the farming of insects.

15. The use of the feed for farming insects according to any of claims 12 to 14, wherein the insects comprise or consist of flies and corresponding larvae, beetles and corresponding larvae, crickets and corresponding larvae, locusts and corresponding larvae, worms and corresponding larvae, moths and corresponding larvae, ants and corresponding larvae, cockroaches and corresponding larvae, termites and corresponding larvae, cicada and corresponding larvae, dragonflies and corresponding larvae, water bugs and corresponding larvae, weevils and corresponding larvae, aphids and corresponding larvae, butterflies and corresponding larvae, or combinations of any of these.

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