21 Feb 2018

Black Soldier Fly for Biodiesel production

Written by scienceandmore
Category: Animal Biology

Black Soldier Fly for Biodiesel production

21.02.2017 / Scienceandmore / Category: Animal Biology

Large amounts of organic wastes accumulate worldwide every year. These wastes comprise for instance of slaughterhouse wastes (approximately 500 million tonnes in the EU annually), whey from cheese production (approximately 50 million tonnes in the EU annually), kitchen and food wastes, and wastes from crop plants, such as crop straw. In attempts to reduce the amount of organic wastes, fat from slaughterhouse wastes is used for the production of bioplastics by the non-pathogenic bacterium Cupriavidus necator for instance (1). In attempts to simultaneously access the waste’s intrinsic energy, organic wastes high in lignocellulose, which is a major component of the cell walls in woody plants, are used to obtain biogas, such as methane, by digestion with anaerobic bacteria (2).

Even though these waste recycling methods reduces the amount of waste, there are still large amounts of organic wastes unutilised. Another way to exploit these resources is the production of biodiesel. Commonly, edible oils from rapeseed, sunflower, and soybean are utilised for biodiesel production. However, these plants are specifically cultivated for biodiesel production. In this way, the production cost of biodiesel is approximately 1.5 times higher than that for conventional mineral diesel. Significantly, the majority of the costs arise from crop production (3,4,5).

In a practical and straightforward alternative to using oil from crop plants, the oils and fats from kitchen and food waste are used instead. In this way, food crops could be channelled into the food production instead of biodiesel production (3,6). The necessity of this transition is apparent considering that the world population will increase to an estimated 9.7 billion by 2050 (7,8).

In addition to the utilisation of oils and fats from kitchen and food waste, the use of the solid residue after oil and fat extraction have been considered for biodiesel production. For this purpose, black soldier fly larvae (BSFL) are reared on these residues and subsequently their fat is extracted. The fat of BSFL meets most of the requirements of the European biodiesel standard EN 14214, and has similar fuel properties as biodiesel from rapeseed oil. Thus, kitchen and food wastes could be used in two ways to obtain fat for biodiesel production (9).

Ultimately, BSFL grow faster, have a higher biomass, and require less area compared to vegetables or even microalgae that also have been proposed for biodiesel production (4).

In 2012, a research team in China obtained almost 24 g of biodiesel from the fat of 1000 BSFL reared on 1 kg of solid organic waste residue. The residue was also reduced by almost 62 % by the BSFL within 7 days (3).

A study with 2000 BSFL that were reared on a mixture of rice straw and kitchen and food waste at several ratios for 10 days showed a production of up to 44 g of biodiesel (10).

In contrast, a study with 500 BSFL that were reared on fermented corncobs, which were previously used for biogas production, for 8 days, only 3.2 g of biodiesel were produced from the BSFL fat. Notably, the fat content in these BSFL was very low. The significantly lower amount of produced biodiesel compared to the previous studies could be attributed to the low nutrition value of fermented corn cobs (2). The fat content of BSFL after all depends on their rearing substrate, and it can be increased by providing a fat-rich substrate (9).

Another study with approximately 1000 BSFL that were reared on cattle, pig or chicken manure yielded 35.5 g, 57.8 g and 91.4 g of biodiesel, respectively (10). This, again, could be attributed to the different nutritional values of the manures.

Besides the rearing substrate for BSFL, different fat extraction methods could also account for the different quantities of fat from BSFL that, subsequently, is used for biodieel production. Mechanical pressing for instance results in low extraction yields, whereas solvent extraction yields higher amounts but require large amounts of solvents (4).

Eventually, the utilisation of a specific rearing substrates and fat extraction method has to be evaluated ecologically and economically for individual biodiesel production operations.

Overall, BSFL could be utilised for biodiesel production from organic wastes. This could, on one hand, reduce the amounts of organic waste, while simultaneously using its still remaining resources, and, on the other hand, channel food crops into food production instead of biodiesel production.

References

1. Kunasundari, B., Murugaiyah, V., Kaur, G., Maurer, F. H. J., & Sudesh, K. (2013) Revisiting the Single Cell Protein Application of Cupriavidus necator H16 and Recovering Bioplastic Granules Simultaneously. PLoS ONE, 8(10), e78528.

2. Li, wu & Li, Qing & Zheng, Longyu & Wang, Yuanyuan & Zhang, Jibin & Ziniu, yu & Zhang, Yanlin. (2015) Potential biodiesel and biogas production from corncob by anaerobic fermentation and black soldier fly. Bioresource technology. 194:276-82.

3. Zheng, Longyu & Li, Qing & Zhang, Jibin & Ziniu, yu. (2012) Double the biodiesel yield: Rearing black soldier fly larvae, Hermetia illucens, on solid residual fraction of restaurant waste after grease extraction for biodiesel production. Renewable Energy. 41, 75-9.

4. Wang, C., Qian, L., Wang, W., Wang, T., Deng, Z., Yang, F., Xiong, J.., Feng, W. (2017) Exploring the potential of lipids from black soldier fly: new paradigm for biodiesel production (I). Renewable Energy. 111: 749-56.

5. Canakci M, Sanli H. (2008) Biodiesel production from various feedstocks and their effects on the fuel properties. J Ind Microbiol Biotechnol. 35:431–41.

6. Patil, P.D., Gude, V.G., Reddy, H.K., Muppaneni, T., Deng, S.G. (2012) Biodiesel production from waste cooking oil using sulfuric acid and microwave irradiation processes. J Environ Pro. 3:107-13.

7. Tilman, D., Balzer, C., Hill, J., & Befort, B. L. (2011) Global food demand and the sustainable intensification of agriculture. Proceedings of the National Academy of Sciences of the United States of America, 108(50), 20260-4.

8. United Nations, Department of Economic and Social Affairs, Population Division (2015) World Population Prospects: The 2015 Revision, Key Findings and Advance Tables. Working Paper No. ESA/P/WP.241.

9. Li Q, Zheng L, Cai H, Garza E, Yu Z, Zhou S. (2011) From organic waste to biodiesel: black soldier fly, Hermetia illucens, makes it feasible. Fuel. 90:1545e8.

10. Zheng, Longyu & Hou, Yanfei & li, wu & Yang, Sen & Li, Qing & Ziniu, yu. (2012). Biodiesel production from rice straw and restaurant waste employing black soldier fly assisted by microbes. Energy. 47. 225-29.

09 Dec 2017

Combining black soldier fly meal and house fly larvae meal for a superior fish feed

Written by scienceandmore
Category: Animal Biology

Combining black soldier fly meal and

house fly larvae meal for a superior fish feed

09.12.2017 / Scienceandmore / Category: Animal Biology

Black soldier fly (BSF) and house fly (HF) have been established for the production of fish feed, and are approved for this purpose by EU legislation since July 2017. The larvae stage of both insects is mainly used since they are high in crude protein. The utilisation of black soldier fly larvae (BSFL) and house fly larvae (HFL) meal as replacement for fishmeal in fish feed has been investigated in several fish species and showed promising results.

Amino Acids

The nutrient content of BSFL and HFL has been shown to vary depending on their rearing substrate, but in general, they consist of 40 % to 60 % crude protein. Even though the larvae’s nutrient content can vary, their amino acid (AA) profiles stay constant. It is also important that the AA profile of fish feed is adjusted to the specific fish species and their nutritional needs. The fish species that are cultivated in aquacultures in the EU are mainly carnivorous and omnivorous, such as salmon and rainbow trout. They evolved with fish as significant nutrient source, and their metabolisms adapted to fish. Therefore, it is important that the AA profile of their feed matches the one of fishmeal. The AA profile of both BSFL and HFL is well balanced and, with some exceptions, relatively close to the one of fishmeal. However, their AA profiles could be optimised, which potentially would result in improved growth and development of fish in aquaculture when these meals are used as feeds. In order to achieve an optimisation, a combination of BSFL and HFL meal in equal amounts could compensate for lower amounts of particular amino acids in one of the meals. The AA profile of BSFL meal, HFL meal, and fishmeal are stated in table 1 (1).

Table 1: Amino acid composition (g/16 g nitrogen) of black soldier fly larvaemeal (BSFLM), house fly larvae meal (FHL), fishmeal, and a calculated combination of BSFLM and HFLM to equal parts.

The low amounts of the essential AAs cysteine and tryptophan in BSFL could be compensated by the higher amounts in HFL and a combination would match the fishmeal proportion much closer. The high amounts of the non-essential AAs aspartic acid, proline and glycin in BSFL could compensate the lower amounts in HFL. Additionally, the proportions of the essential AAs valin, phenylalanine and tyrosine are higher in both insect species compared to fishmeal. However, both BSFL and HFL have lower amounts of lysine and threonine. These two AA could be supplemented to bring the AA profile of insect meal to the level of fishmeal. The other AA are similar in content compared to fishmeal (1,2).

The amino acid profile of soy, another substantial component of fish feed, is fairly similar to the one of fishmeal, too (1,2). This suggests that BSFL or HFL meal could possibly substitute for soy or fishmeal, or both. A reduction of soy and/or fishmeal in fish feed would decrease the environmental and ecological impact of these feed materials.

Calcium and phosphorous

BSFL are generally rich in calcium, whereas house fly larvae are very low (7.6 % and 0.5 % of dry mass). Here again, a combination of both insect species could compensate the lack in one species and raise the amount of calcium to fish meal levels (4.3 % of dry mass) (1,2). This, however, is of secondary concern since some fish species have been shown to obtain calcium directly from water (3). Phosphorous levels are low in both species, and an addition of phosphorous could potentially be required (1,2).

Fatty acids

Analyses of BSFL and HFL found that their lipid contents and fatty acid profile highly depend on their rearing substrate. Generally, the lipid content of BSFL is between 24 % and 49 %; and for HFL 9 % up to 26 %.

When BSFL and HFL were reared on cow manure, their fatty acid composition showed high levels of saturated and mono-unsaturated fatty acids, as well as low levels of omega-3 fatty acids, such as EPA and DHA. When fish offal was added to the cow manure, the content of beneficial omega-3 fatty acid in BSFL increased rapidly. Similarly, HFL that were reared on plant based substrate were low in omega-3 fatty acids (4,5).

The utilisation of BSFL and HFL as fish meal replacement in fish feed could therefore result in an alteration of the fatty acid profile in fish. Due to the inability of fish to produce omega-3 fatty acids themselves, they depend on the feed source for these fatty acids. It would be beneficial for fish performance, as well as for the consumer who eat these fish, if their feed would contain a higher amount of omega-3 fatty acids. Ultimately, fish are regarded as a source of omega-3 fatty acids by consumers. It was implicated that a diet with a low omega-6 to omega-3 fatty acid ratio (n-6:n-3 ratio), i.e. higher amounts of omega-3 fatty acids, leads to reduced inflammation and potentially improved prevention of cardiovascular heart disease (6).

The process of providing high amounts of omega-3 fatty acids to fish via larvae is complicated and not solved thus far. It has been suggested to feed larvae fish offal, microalgae and phytoplankton as omega-3 fatty acid sources. This, however, would be uneconomic since these materials could be fed to fish directly by mixing them in the fish feed (7). However, a specific process that is used in other livestock could be adapted. Here, the animals are fed a certain diet before their slaughter in order influence their fat content and fatty acid profile. Similarly, the fish rearing process could be separated in two stages. During the first stage, when the fish grow and develop rapidly, higher amounts of insect meal and insect oil instead of fishmeal and fish oil could be provided. During the second stage, before the fish are caught, higher amounts of fishmeal in the fish feed would increase their omega-3 fatty acid content. Ultimately, the aim is to achieve a high content of omega-3 fatty acids in fish for the consumer (4).

Overall, a combination of BSFL meal and HFL meal in fish feed could be superior to BSFL meal or HFL meal alone in terms of fish growth and development. However, future investigations are necessary to evaluate this approach.

References

1. Makkar, H.P.S., Tran, G., Heuzé, V., Ankers, P. (2014) State-of-the-art on use of insects as animal feed. Animal Feed Science and Technology, 197, 1-33.

2. Tran, G., Heuzé, V., Makkar, H.P.S. (2015) Inserts in fish diets. Animal Frontiers 5(2): 37-44.

3. Simkiss, K. (1974) Calcium metabolism of fish in relation to aging. In Aging of Fish (Ed. by Begenal, T.B., pp. 1-12. Unwin Brothers, Woking.

4. Henry, M., Gasco, L., Piccolo, G., Fountoulaki, E. (2015) Review on the use of insects in the diet of farmed fish: Past and future. Animal Feed Science and Technology, 203:1-22.

5. Hussein, M., Pillai, V. V., Goddard, J. M., Park, H. G., Kothapalli, K. S., Ross, D. A., et al. (2017) Sustainable production of housefly (Musca domestica) larvae as a protein-rich feed ingredient by utilizing cattle manure. PLoS ONE, 12(2), e0171708.

6. Simopoulos A.P. (2002) The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. 2002 Oct;56(8):365-79.

7. Norambuena, F., Hermon, K., Skrzypczyk, V., Emery, J. A., Sharon, Y., Beard, A., & Turchini, G. M. (2015) Algae in Fish Feed: Performances and Fatty Acid Metabolism in Juvenile Atlantic Salmon. PLoS ONE, 10(4), e0124042.

03 Dec 2017

House fly larvae as fish feed in the EU

Written by scienceandmore
Category: Animal Biology

House fly larvae as fish feed in the EU

03.12.2017 / Scienceandmore / Category: Animal Biology

The house fly (HF) (scientifically Musca domestica) is another insect that can be used to convert organic wastes into high protein animal feed.

Mature house flies are greyish in colour, covered in hair, and around 6 to 7 mm long. In general, they live 15 to 25 days. Four to 20 days after copulation, female HFs lay around 500 eggs spread across a couple of days, often into moist substrate such as manure or garbage heaps. Whitish larvae hatch from these eggs within eight to 20 hours after ovipositon (egg deposition). House fly larvae (HFL) immediately start to feed on the present organic material, and require four to 30 days to complete their larval stage and enter pupation, depending on temperature and nutrient availability. Pre-pupal larvae are approximately three to nine mm in length and weigh around 13 mg (1,2).

Pros and Cons of house flies for animal feed production

An advantage of HF is that females lay a large amount of eggs; approximately 500 eggs in the wild and more than 2000 eggs in the controlled environment of the lab. Accompanied by the completion of their larval stage within four days under optimal conditions, HFs seem to be suited for a rapid production of larvae for animal feed production. Similar to BSF, the pre-pupa larval stage is commonly utilised for animal feed production.

HFL can grow on a wide range of organic substrates, including nutrient-poor cow manure, suggesting that they are relatively frugal. This characteristic could be used to turn organic wastes or low-quality substrates into high quality protein for animal feed, as well as nutrient rich fertilisers. HFL also require only small amounts of substrate for feeding, partly due to their fast life cycle. Around 1500 larvae have been reared on around 450 g of fresh manure.

In many studies, animal manure has been used as substrate for HFL. Interestingly, investigations showed that HFL feed on microbes that can be found in great numbers on manure. It has been hypothesised that the actual feed for HFL are microbes and not so much the manure itself (2,3). This, however, could relativise the utilisation of HFL for fish feed production in the EU due to the restrictions for substrates according to EU legislation. Approved substrates could be wheat bran for example. This substrate, however, would potentially not host enough microbes to effectively nourish HFL. Eventually, further investigations are needed to confirm this hypothesis.

The migration behaviour of HFL for pupation could be used for self-collection, similar as it has been proposed for BSFL. However, opinions differ on this topic, since it has been found that HFL grow in manure, pupate directly there and emerged as adult flies without migration to dryer spaces upon pupation. Thus, other collection methods that utilise mesh could be used. Here, the substrate with larvae is spread in a thin layer on the mesh and is subsequently exposed to light. HFL are photophobic and will try to escape the light by migration through the mesh into a container placed below (2,3).

The possession of mouth parts of adult HF and their requirement to feed is regarded as a disadvantage. Adult HF externally liquefy their feed via saliva, which is considered to be the time of possible pathogen transmissions. HF are considered as a pest and carriers of diseases due to this feeding mechanisms, however, no pathogen contamination of fish via HFL meal has been reported (2,4).

HFL also require temperatures between 25 °C and 32 °C, and a high humidity between 60 % and 75 % for optimal growth and development. This could necessitate additional temperature and humidity control, especially during the colder months of the year (1,3).

Hands-on experience found a strong unpleasant odour emerging at the rearing site of HFL. Pests could potentially be attracted to the rearing site when it is situated outside. The odour could also be a nuisance for adjacent neighbours, especially during summer months. Therefore, it could be more suitable to rear HFL in a controlled indoor environment with forced ventilation and gas cleaning.

Nutrient composition of house fly larvae

The nutrient content of HFL varies based on their rearing substrate. Generally, HFL consists of 40 % to 60 % crude protein (which is lower than fishmeal with around 65 % crude protein). The quality of the crude protein is determined by its amino acid (AA) balance. Since fish in aquaculture are mostly omnivorous and carnivorous, and are known to prey on other fish, the AA profile of a fish feed should be oriented towards the profile of fishmeal. Compared to fishmeal, HFL meal has a modestly lower amount of the AAs isoleucine, leucine, and lysine. It has often been suggested to supplement the AAs that are low in concentration in order to bring the AA profile of insect meal up to par with the one of fishmeal. This approach, however, was objected to and no addition of AA has also been proposed (2). Eventually, investigations in different fish species, accompanied by economic calculations, would be necessary to clarify if an AA supplementation is appropriate or even needed.

The lipid content of HFL is also dependent on their rearing substrate, but is generally between 9 % to 26 %. It has been found that more than half (around 57 %) of the HFL oil of larvae reared on cow manure consists of monounsaturated fatty acids; saturated fatty acids form the second largest amount (around 38 %). This HFL oil is low in polyunsaturated fatty acids (4 %), specifically in omega-3 fatty acids (less than 1%). This could be problematic for fish in aquaculture due to their inability to synthesise essential fatty acids like omega-3 fatty acids. The fatty acid profile of BSFL has already been indicated to affect its utilisation in certain fish species. Therefore, it has been suggested to add omega-3 fatty acids by ways of algae for example (2). This approach, however, is questionable.

The phosphorus content in HFL is high (nine to 24 g per kg dry mass) and similar to the one of BSF. However, HFL contain significantly less calcium than BSFL (three to eight g per kg dry mass). Overall, phosphorous and calcium levels are lower than in fishmeal (but higher than in soy). Calcium could be added to HFL meal to improve the calcium:phosphorous ratio. This, however, seems to depend on the fish species the HFL meal is intended for. Several fish species have been shown to obtain calcium directly from water and do not depend on calcium intake from their feed (3,4,5).

Photo by Jeremy Cai on Unsplash-for blog

House fly larvae meal in fish feed

Similar to BSFL, only few investigations have been conducted on the use of HFL as fish feed, and even fewer specifically in fish species that are reared in the EU.

In a 25 days trial, meal from HFL that were cultivated on hen manure could replace 100 % of fishmeal (30 % dietary inclusion) in the diet of common carp without detrimental effects on the digestibility of the fish feed (6).

During a nine weeks trial in rainbow trout, replacement of 25 % of fishmeal with HF pupae meal (larvae were reared on cow manure) resulted in reduced growth of trout. This, however, is stated with the caveat that the control group consumed more calories than the replacement diet group, due to a calculation error made during the diet formulation, that could have contributed to the differences in feed conversion between groups. The lipid content in the fillet of trout fed with HF pupae meal was slightly lower than the one of fishmeal-fed trout. However, the fatty acid profile of HF pupae meal-fed trout showed reduced levels of healthy omega-3 fatty acids (7). This result has already been observed in BSFL meal-fed fish, and a strategy of applying a finishing diet for rainbow trout has been suggested.

In other fish species such as Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus), HFL meal up to a dietary inclusion of 25 %, which represents around 35 % to 100 % replacement of fishmeal according to different studies, resulted in similar fish growth as diets with fishmeal. Here again, the fish were low in omega-3 fatty acids (3,8).

Research on the utilisation of HFL meal in feed for fish that are mainly reared in the EU is still in its early stages. Future investigations could aim to determined how much dietary inclusion of HFL meal is tolerated by these fish species, as well as if defatted HFL meal in the feed affects fish performance, as suggested by findings in BSFL. Here, it was found that when BSFL are reared on a mixture of cow manure and fish offal, instead of cow manure alone, no effects on rainbow trout performance was observed, whereas the sole use of cow manure resulted in BSFL meal that lead to reduced trout growth (9).

References

1. Sanchez-Arroyo, H., Capinera, J.L. (2017) House fly: Musca domestica. [online] Featured Creatures. Available at: http://entnemdept.ufl.edu/creatures/urban/flies/house_fly.HTM [Accessed: 04.11.2017].

2. Hussein, M., Pillai, V. V., Goddard, J. M., Park, H. G., Kothapalli, K. S., Ross, D. A., et al. (2017) Sustainable production of housefly (Musca domestica) larvae as a protein-rich feed ingredient by utilizing cattle manure. PLoS ONE, 12(2), e0171708.

3. Makkar, H.P.S., Tran, G., Heuzé, V., Ankers, P. (2014) State-of-the-art on use of insects as animal feed. Animal Feed Science and Technology, 197, 1-33.

4.NCIPMI (1998) Insect and related pests of man and animals. North Carolina Integrated Pest Management Information. [online] Available at: http://ipm.ncsu.edu/AG369/notes/black_sol-dier_fly.html [Accessed: 05.11.2017]

5. Simkiss, K. (1974) Calcium metabolism of fish in relation to aging. In Aging of Fish (Ed. by Begenal, T.B., pp. 1-12. Unwin Brothers, Woking.

6. Ogunji, J., Pagel, T., Schulz, C., Kloas, W. (2009) Apparent digestibility coefficient of housefly maggot meal (magmeal) for Nile tilapia (Oreochromis niloticus L.) and carp (Cyprinus carpio). Asian Fisheries Science. 22: 1095-1105.

7. St-Hilaire, S., Sheppard, C., Tomberlin, J.K., Irving, S., Newton, L., McGuire, M.A., Mosley, E.E., Hardy, R.W., Sealey, W. (2007) Fly prepupae as a feed stuff for rainbow trout, Oncorhynchus mykiss. J. World Aquacult. Soc. 38:59-67.

8. Tran, G., Heuzé, V., Makkar, H.P.S. (2015) Inserts in fish diets. Animal Frontiers 5(2): 37-44.

9. Henry, M., Gasco, L., Piccolo, G., Fountoulaki, E. (2015) Review on the use of insects in the diet of farmed fish: Past and future. Animal Feed Science and Technology, 203:1-22.

09 Nov 2017

Black soldier fly larvae as fish feed in the EU

Written by scienceandmore
Category: Animal Biology

Black soldier fly larvae as fish feed in the EU

09.11.2017 / Scienceandmore / Category: Animal Biology

According to regulation (EU) N° 2017/893, processed animal protein (PAP) from several insect species are approved for the production of feed for animals in aquaculture in the EU. The animals in aquaculture that require ample feed are mainly the following carnivorous and omnivorous fish:

Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), gilt-head seabream (Sparus aurata), European bass (Dicentrarchus labrax), common carp (Cyprinus carpio), and Atlantic bluefin tuna (Thunnus thynnus). In general, a major part of their diet in the wild are other fish and shellfish, but also insects (see previous article).

This article discusses the utilisation of black soldier fly as feed for these fish species. Here, the larval stage shortly before the transition to pupa, i.e. prepupa, is the main development stage that is used for fish feed production, as prepupae contain the highest amounts of protein and fat (egg → larva → pupa → adult fly).

Black Soldier Fly (scientiflcally Hermetia Illucens)

Black soldier flies (BSF) (family Stratiomyidae) are found in tropical and warmer temperate regions. Adult flies are black in colour and of wasp-like shape with a length of approximately 15 to 20 mm. Mature BSF live for approximately 5 to 8 days. During this time they do not take up feed due to their lack of mouth pieces. They solely rely on the storage they built up during their larval stage. The mature female fly can mate after two days and oviposit (laying eggs) quickly after (1). Female BSFs lay more than 500 eggs that makes BSF very interesting in terms of utilisation for the production of animal feed (2). From eggs, whitish black soldier fly larvae (BSFL) hatch that reach an approximate length of 27 mm, width of 6 mm, and weigh of 220 mg as prepupae.

An advantage of BSFL is that they can feed on a wide range of substrates, including food and kitchen scraps, coffee bean pulp, but also other organic wastes such as distillers grains and fish offal, as well as animal manure. A single BSFL can feed on 25 to 500 mg of fresh matter per day, which makes them important decomposers of organic substrates. Due to the quick processing and drying, organic wastes do not tend to emit odour. Subsequently, the residual organic waste could be used as fertiliser since it is still rich in nutrients (1,3). Due to EU legislation, utilisable substrates are restricted and BSFL are not allowed to be reared on manure or food wastes, if they are intended for the production of PAP in animal feed.

In order to optimally rear BSFL, proteins, carbohydrate, fats and a certain structure of the substrate need to be provide. Different ecologically and economically sustainable substrates have been used, such as mixtures that are used for laying hens (mix of maize, wheat, sunflower cake, calcium carbonate, soybean cake, peas, rapeseed cake, rice bran, spelt husks, monocalcium phosphate, soybean oil, sodium chloride, sodium bicarbonate), but also mixtures of cereal processing leftovers (grinding dust, broken pellets and spilled grains), leftovers of distilling processes (dried barley, corn, wheat and sugar syrups), dried sugar beet pulp, and plant compost from tomatoes (4,5,6).

Another advantage of BSFL is their migrating behaviour at the end of their larval stage that can be utilised for collection. The larvae migrate from their humid substrate in order find a dry and protected site for pupation. A self-collection method has been developed by Diener et al. (2011). Here, the larvae climb up a ramp out of the cultivation container and are collected in another container at the end of the ramp (7). However, it has been stated that the utilisation of the migration behaviour does not work as expected, as a uniform migration was not obtained, and a high mortality rate was found due to the artificially high humidity in the substrate. It was concluded that sieving is required for separation of the larvae from their substrate (4).

A disadvantage of BSF is the potentially long period for the larvae to reach their final larval stage. It can last from two weeks up to four months depending on nutrient quality and availability, as well as environmental conditions. For propagation purposes, the subsequent pupal stage can last from 14 days up to 5 months. BSFs and BSFL also require a stable warm and humid environment (between 27 °C and 30 °C, and 50 % to 70 % humidity) that possibly necessitates additional heating and air humidification during cultivation in order to optimise development and growth (1,4,8).

In terms of nutrient content, BSFL contain 40 to 44 % crude protein, which makes them a rich protein source for animal feed. Their fat content can vary greatly and has been shown to depend on the substrate. Oil-rich substrates for example resulted in a fat content of 42 % to 49 %, but also in reduced protein content (1,10).

BSFL are rich in calcium but poor in phosphorus compared to fishmeal (5 % to 8 % of dry matter and 0.6 % to 1.5 % of dry matter, respectively). They have a rather unsuitable calcium:phosphorous ratio for fish feed that, however, could be improved by adding phosphorous. Desired ratios range between 1.1 to 1.4. BSFL have 35 % to 45 % dry matter, which is relatively high and makes it easier to dehydrate them (1,9,10).

Investigations on BSFL as feed for the fish species that are mainly reared in aquaculture in the EU are scarce.

An 8 weeks investigation in the mainly carnivorous rainbow trout (Oncorhynchus mykiss) showed that meal of BSFL could replace 25 % and 50 % of the fishmeal, representing 16 % and 33 % of the total feed (dietary inclusion), without adverse effects on rainbow trout growth and development compared to fish fed with 29 % fishmeal in their diet. The rainbow trout fillets also did not have differences in sensory quality. This, however, was only observed when BSFL were reared on a substrate that consisted of cow manure and fish offal in equal proportions. When BSFL were reared on cow manure only, replacement of fish meal lead to reduced growth of rainbow trout (10). In a 9 weeks study where 25 % of the fishmeal was replaced with BSFL meal, representing 15 % of the total diet, rainbow trout growth was also not affected. Replacement of 50 % of fishmeal, representing 30 % dietary inclusion, however resulted in reduced growth compared to fish fed with fishmeal (36 % dietary inclusion). Here, BSFL were reared on pig manure (10).

Conversely, in an 8 weeks trial where BSFL were reared on tomato plant compost, which would be in compliance with EU legislation, up to 50 % of fishmeal was replaced by BSFL meal without losses in rainbow trout performance or sensory quality (6). These results suggest that the composition of the substrate for BSFL affects their applicability in rainbow trout feed.

These investigations utilised full fat BSFL meal. Two other studies investigated the utilisation of defatted BSFL meal (by mechanical pressure). In an 11 weeks trial with defatted BSFL meal, where BSFL were grown on plant based substrate according to EU legislation, a replacement of up to 50 % of the fishmeal, which represented 40 % dietary inclusion, resulted in similar survival and growth of rainbow trout compared to the fishmeal control diet. Digestibility of the BSFL diet was found to be very good and no alterations of the intestinal morphology of rainbow trout were observed (11). Similarly, in a 7 weeks trial with BSFL reared on food and kitchen scraps (pasta, spent brewer grains, fruit and vegetable leftovers), the defatted meal was used to replace 46% of the fishmeal, which corresponded to 28 % diet inclusion. No differences were observed in terms of weight gain between the replacement diet and the control diet that utilised fishmeal. Also, no significant differences in taste and odour were found between BSFL meal and fishmeal fed rainbow trout. The fillet of BSFL meal fed fish, however, was a little darker in colour (12). Yet, detrimental effects on the fatty acid profile, specifically on the beneficial fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), were found in rainbow trout when BSFL meal replaced 50 % of fish meal (lipids health indices were also negatively affected). Fatty acid profile differences between control diet and 25 % replacement diet were rather small. It was suggested that the higher amount of fishmeal and therefore fish oil in the 25 % replacement diet provided enough beneficial fatty acids (11).

It could be hypothesised that the fatty acid profile of rainbow trout fed with a 50 % BSFL replacement diet could be improved before butchering by feeding them a finishing diet that contains higher amounts of fishmeal.

In a 15 weeks study with the carnivorous Atlantic salmon (Salmo salar), it was found that a replacement of 25 %, 50 % or 100 % of fishmeal with BSFL meal, representing 5 %, 10 % and 25 % dietary inclusion, performed equally well as the control diet with 20 % fishmeal. Fish of all four groups showed similar growth. The amount of the beneficial fatty acids EPA and DHA was slightly reduced in salmon that were fed with the 50 % and 100 % replacement diet, but not with the 25 % replacement diet. However, fish oil and rapeseed oil were added to all diets, which relativises the fatty acid profile results. Sensory testing of fillets of fish from all four groups yielded no differences. Histological investigations also did not show significant physiological changes. The researchers suggested that the preparation method of BSFL meal could affect performance in fish. When the BSFL meal was highly defatted, salmons showed reduced weight gain with all three replacement diets compared to the control diet that contained 20 % fishmeal (BSFL were reared on human food waste, which would not be approved according to EU legislation) (10,13).

Speculations about the reasons for the observed weight gain differences are hard to make due to the lack of studies in Atlantic salmon.

A 9 weeks investigation in the carnivorous European bass (Dicentrarchus labrax) showed that replacing 20 %, 40 %, and 60 % of fishmeal with BSFL meal in the fish diet, corresponding to dietary inclusion of 6.5 %, 13 % and 19.5 %, did not significantly affect growth and development of the European bass compared to control diet (32 % fishmeal). No palatability issues were observed. This study, however, had a relatively low sampling size of 10 fish per group (14).

In a 10 weeks trial, gilthead seabream (Sparus aurata) were either fed a fishmeal diet with 45 % fishmeal (control diet) or a replacement diet where 10 %, 20 % or 30 % of the fishmeal was substituted by BSFL meal (corresponding to 9.5 %, 19.4 %, and 27.6 % dietary inclusion). Substrate for BSFL mainly consisted of plant based organic wastes. All replacement diets performed worse than the control diet and the replacement diet fed fish showed reduced growth. Palatability of BSFL meal was also found to be reduced. The researchers suggested that the reduced weight gain of gilthead seabream fed with the replacement diets was caused by lower feed consumption due to lower palatability of BSFL meal (15).

Overall, the results of these investigations suggest that BSFL meal can replace fishmeal in parts. The composition of the substrate for BSFL and the fat content of the BSFL meal seem to play crucial roles for the utilisation of the BSFL as fish feed. Research results indicate that plant based substrates and defatting of BSFL meal allow for a higher dietary inclusion without detrimental effects of rainbow trout performance. Atlantic salmon seems to depend much more on a high fat content of the feed for optimal growth and development. European bass appears to manage well with BSFL meal as fishmeal replacement, whereas for gilthead seabream, BSFL meal could be less palatable. It must be noted that the development stages of the fish varied between the mentioned studies. This could be a reason for the different results, since fish at different developmental stages require different diets. In general, the predatory consumption of other fish increases with age. Comprehensive studies across the whole life cycle of fish could shed more light into the applicability of BSFL meal in fish diets.

References

1. Makkar, H.P.S., Tran, G., Heuzé, V., Ankers, P. (2014) State-of-the-art on use of insects as animal feed. Animal Feed Science and Technology. 197:1-33.

2. NCIPMI (1998) Insect and related pests of man and animals. [online] North Carolina Integrated Pest Management Information. Available at: http://ipm.ncsu.edu/AG369/notes/black_sol-dier_fly.html [Accedssed: 02.11.2017].

3. PROteINSECT (2016) Insect Protein – Feed for the Future. [online] Minerva Communications UK Ltd. Available at: https://www.fera.co.uk/media/wysiwyg/our-science/proteinsect-whitepaper-2016.pdf [Accessed: 02.11.2017]

4. Katz (2013) Endbericht zum Forschungsvorhaben „Entwicklung eines Verfahrens zur industriellen Produktion von Präpuppen der Fliege Hermetia illucens zur Futterproteinproduktion. [online] Heretia Futtermittel GbR. Available at: http://www.katzbiotech.de/hermetia/dokumente/Abschlussbericht%20Hermetia%20FuE%20Brandenburg.pdf [Accessed: 03.11.2017]

5. Tschirner, M., Simon, A. (2015) Influence of different growing substrates and processing on the nutrient composition of black soldier fly larvae destined for animal feed. Journal of Insects as Food and Feed. 1(4):249-59.

6. Stamer, A., Wesselss, S., Neidigk, R., Hoerstgen-Schwark, G. (2014) Black Soldier Fly (Hermetia illucens) larvae-meal as an example for a new feed ingredients’ class in aquaculture diets. [Conference paper] Proceedings of the 4th ISOFAR Scientific Conference 2014.

7. Diener, S., Zurbrügg, C., Roa Gutiérrez, F., Nguyen Dang Hong, Morel, A., Koottatep, T., Tockner, K., (2011) Black soldier fly larvae for organic waste treatment – prospects and constraints. [Conference paper] WasteSafe 2011 – 2nd Int. Conf. on Solid Waste Management in the Developing Countries. 13-15 February 2011.

8. Tomberlin, J.K., Adler, P.H., Myers, H.M. (2009) Development of the Black Soldier Fly (Diptera: Stratiomyidae) in Relation to Temperature. Environ Entomol. 38(3):930-4.

9. Tran, G., Heuzé, V., Makkar, H.P.S. (2015) Inserts in fish diets. Animal Frontiers 5(2):37-44.

10. Henry, M., Gasco, L., Piccolo, G., Fountoulaki, E. (2015) Review on the use of insects in the diet of farmed fish: Past and future. Animal Feed Science and Technology. 203:1-22.

11. Renna, M., Schiavone, A., Gai, F., Dabbou, S., Lussiana, C., Malfatto, V., Prearo, M., Capucchio, M.T., Biasato, I., Biasibetti, E., De Marco,M., Brugiapaglia, A., Zoccarato, I., Gasco, L. (2017) Evaluation of the suitability of a partially defatted black soldier fly (Hermetia illucens L.) larvae meal as ingredient for rainbow trout (Oncorhynchus mykiss Walbaum) diets. Journal of Animal Science and Biotechnology. 8, 57.

12. Stadtlander, T., Stamer, A., Buser, A., Wohlfahrt, J., Leiber, F., Sandrock, C. (2017) Hermetia illucens meal as fish meal replacement for rainbow trout on farm. Journal of Insects as Food and Feed. 3(3):165-75.

13. Lock, E.R., Arsiwalla, T., Waagbo, R. (2016) Insect larvae meal as an alternative source of nutrients in the diet of Atlantic salmon (Salmo salar) postsmolt. Aquac Nutr. 22:1202-13.

14. Sánchez López, A. (2015) Potential of pre-pupae meal of the Black Soldier Fly (Hermetia illucens) as fish meal substitute: effect on growth performance and digestibility in European sea bass (Dicentrarchus labrax). Mster thesis. Universitat Politecnia Valencia.

15. Karapanagiotidis, I.T., Daskalopoulou, E., Vogiatzis, I., Rumbos, C., Mente, E., Athanassiou, C.G. (2014) SUBSTITUTION OF FISHMEAL BY FLY Hermetia illucens PREPUPAE MEAL IN THE DIET OF GILTHEAD SEABREAM (Sparus aurata). [Conference Paper] HydroMedit 2014, November 13-15, Volos, Greece.

25 Oct 2017

Insect based feed for animals in aquaculture in the EU

Written by scienceandmore
Category: Animal Biology

Insect based feed for animals
in aquaculture in the EU

25.10.2017 / Scienceandmore / Category: Animal Biology

Recent changes in EU legislation allow feeding of animals in aquaculture with processed animal protein (PAP) from insects since July 2017. This amendment mainly affects insect meal (dried insects ground to meal) that consists of protein to a big proportion, especially when it is defatted. Oil from insects, as well as fresh or unprocessed dried insects are not included in this restrictions by EU legislation and can be fed to animals in aquaculture, pets, poultry and pigs. Here the question arises, why would insect meal be preferred over fresh and dried insects? Insect meal can be mixed with other feed components such as ground grains and soy to form a mixture of desired composition that is then pressed in pellets for better and more convenient feeding to animals.

Animals in aquaculture are mostly reared by the five EU member states Spain, UK, France, Italy and Greece, who produce around 75 % of the animals in the EU. 294,000 tons of animals in aquaculture were reared by Spain (equals 23.0 % of the EU total, with a worth of approximately €513 million), 212,000 tons by the UK (16.6 %, €995 million), 180,000 tons by France (14.1 %, €627 million), 149,000 tons by Italy (11.6 %, €437 million) and 106,000 tons by Greece (8.3 %, €463 million) (1). Here, the most relevant and important animals are molluscs and fish, and the following 10 species account for around 90 % of the total weight in the EU in descending order:

1) Mediterranean mussel (Mytilus galloprovincialis), 2) Atlantic salmon (Salmo salar), 3) rainbow trout (Oncorhynchus mykiss), 4) blue mussel (Mytilus edulis), 5) gilt-head seabream (Sparus aurata), 6) Pacific oyster (Magallana gigas), 7) European bass (Dicentrarchus labrax), 8) common carp (Cyprinus carpio), 9) Japanese carpet shell (Venerupis philippinarum), and 10) Atlantic bluefin tuna (Thunnus thynnus).

This is stated with the annotation that the EU consists of different countries with different geography, and that the various fish species also have different natural habitats. 95% of the Atlantic salmon is reared in the UK, and 87% of Pacific oyster in France for instance (1). At the same time, other species have wider dissemination. Rainbow trout for example is reared by 17 of the EU member states and the common carp by 13 states as one of their major fish species (2).

In terms of species-specific feed in the wild, the three molluscs Mediterranean mussel, blue mussel and Pacific oyster consume bacteria, phytoplankton and other small organic matter. In aquaculture, their cultivation does not require additional feed (3-5).

The stated seven fish species are carnivorous or omnivorous and a major part of their diet in the wild are other fish and shellfish, but also insects (6-9). As of yet, fish in aquaculture have been fed with fishmeal and plant-based feeds, as well as oil from fish and plants. Due to the increasing prices of fishmeal and fish oil, more and more plant-based material from legumes, oil seeds or cereal gluten has been introduced to animal feed. It seems, however, difficult to substitute large amounts of fishmeal and especially fish oil with plant based material. They have disadvantages compared to fishmeal, such as less palatability, anti-nutritional components, high fibre and non-starch polysaccharides content, and a fatty acid and amino acid profile that were proposed to be less suitable than the ones of fishmeal (1).

Insect meal could be a beneficial addition in fish feed and could substitute parts of fishmeal and plant content, since the amino acid profile of insects is more comparable to fishmeal than the one of plants to fishmeal (11). However, depending on the utilised insect species, insect proteins could still be low in the amino acids such as methionine and lysine that potentially would make it necessary to supplement these in animal feeds, specifically for growing animals. This also suggests that insect meal could only partially substitute fishmeal (12,13). The combination of different insect species could compensate the lack of certain amino acids in one of the species. Considering the amino acid profiles of black soldier fly and house fly larvae, they partly complement each other and together they match the profile of fishmeal much closer than the individual ones. The low levels of tryptophan in black soldier fly larvae could be compensated by the higher amounts in house fly larvae for instance.

Fish oil contains higher amounts of omega-3 fatty acids than vegetable oil that are in particular important for carnivorous species such as salmon and trout. The amount of these fatty acids could be insufficient for the fish if the plant content of their feed would be higher (10). The ratio of alpha-linolenic acid (one of the three omega-3 fatty acids) to linoleic acid in insect oils is not as good as in fish oils, but in general better than in vegetable oils. Nevertheless, this is one of the limiting factors for the utilisation of insect meal and insect oil in fish feed, since fish need these fatty acids due to limited metabolic capabilities to synthesis them or due to better growth and development when these fatty acids are provided in their diet (13). However, investigations showed that the fatty acid composition of insects can be modified by modulating the content of their substrate (12,13), and thus potentially adjusted to fit more closely the requirements of a specific fish species.

Fish diets contain relatively low levels of carbohydrates, and the most common carbohydrate would be chitin that is probably digested to a degree by fish. Investigations showed chitinase activity, an enzyme that is involved in chitin digestion, in several fish species. The addition of chitin to fish feed of marine fish has even been suggested to have beneficial effects on these fish. Insects contain low levels of carbohydrates that were estimated to be less than 20 %, and chitin forms the majority of it. However, it is agreed upon that chitin is another limiting factor for the utilisation of insect in fish feed (2014).

Insects are in general relatively low in calcium compared to fish meal, although there are exceptions like the black soldier fly that is high in calcium. Soy is also characterised by low levels of calcium. However, similar to the fatty acid content, calcium content of insects can be affected by the calcium content of their substrate. Nevertheless, addition of calcium could be necessary to ensure optimal development and growth of fish. Phosphorus levels are also relatively low in insects, as well as in soy, compared to fishmeal. An important factor for fish feed is the ratio of calcium to phosphorous and would possibly need adjustment to reach 1.1 to 1.4 as found in fishmeal (13).

According to EU legislation, seven insect species are allowed for the production of animal feed in aquaculture (Regulation (EU) N° 2017/893):

1) black soldier fly (Hermetia illucens), 2) housefly (Musca domestica), 3) mealworm or yellow mealworm (Tenebrio molitor), 4) lesser mealworm or litter beetle (Alphitobius diaperinus), 5) house cricket (Acheta domesticus), 6) tropical house cricket or banded cricket (Gryllodes sigillatus), and 7) Jamaican field cricket (Gryllus assimilis).

These species are regarded as non-pathogenic and do not pose a risk for human, animal or plant health. Furthermore, they do not transmit human, animal or plant pathogens, i.e. are not regarded as vectors, are not protected species or invasive alien species. In fact, they are now classified as „farm insects” and have a similar status as livestock (according to EG 1069/2009 of the new legislation). The new legal status of these seven insects has certain additional consequences and regulation that need to be abided by. For animal feed production purpose, a cultivation of these insects is not allowed on substrate that contains kitchen or food scraps, meat or bone meal, liquid manure or faeces (according to EG 999/2001 and EG 767/2009).

Allowed are substrates of:

1) non-animal origin or

2) animal origin that fall within category 3 substances, specifically fish meal, blood products of non-ruminants, Dicalciumphosphate and Tricalciumphosphate, hydrolysed proteins from non-ruminants, hydrolysed proteins of ruminants and their hides, gelatine and collagen of non-ruminants, eggs and egg products, milk and dairy-based substances, colostrum, honey, and rendered fats (amended schedule XIV, chapter I, clause 2, section 5 b and c of the EU 142/2011).

Significantly, high importance was placed on the exclusion of unprocessed products of ruminant origin to prevent potential cross-contamination with prions. Prions were attributed for the catastrophic outbreak of BSE in the 90s. These substrate regulations also apply for insect meal that is imported from non-EU counties into EU countries.

Next article: Black soldier fly larvae as fish feed in the EU

References

1. Eurostat (2016) Dive into aquaculture in the EU. [online] Eurostat. Available at: http://ec.europa.eu/eurostat/en/web/products-eurostat-news/-/DDN-20171018-1 [Accessed 19.10.2017].
2. Eurostat and Eumofa (2013) European Commission – Fisheries – 4. Fisheries and aquaculture production [online]. Available at: https://ec.europa.eu/fisheries/4-fisheries-and-aquaculture-production_en [Accessed 20.10.2017].
3. MarLIN (2006) BIOTIC – Biological Traits Information Catalogue. [online] Marine Life Information Network. Plymouth: Marine Biological Association of the United Kingdom. Available at: www.marlin.ac.uk/biotic [Accessed 19.10.2017].
4. Department of Agriculture, Forestry and Fisheries (DAFF) (2017) Mediterranean mussel Mytilus galloprovincialis. [online] Available at: http://www.nda.agric.za/doaDev/sideMenu/fisheries/03_areasofwork/Aquaculture/BIODIVERSITY/M.%20galloprovincialis%20BRBA%2012.12.12.pdf [Accessed 19.10.2017].
5. FAO (2017) Ruditapes philippinarum (Adams & Reeve, 1850). [online] Cultured Aquatic Species Information Programme. Available at: http://www.fao.org/fishery/culturedspecies/Ruditapes_philippinarum/en [Accessed 25.10.2017].
6. Rochard, E. and P. Elie (1994) La macrofaune aquatique de l’estuaire de la Gironde. Contribution au livre blanc de l’Agence de l’Eau Adour Garonne. In État des connaissances sur l’estuaire de la Gironde (ed. by Mauvais, J.-L. and Guillaud, J.-F.), pp 1-56. Agence de l’Eau Adour-Garonne, Éditions Bergeret, Bordeaux, France.
7. Frimodt, C. (1995) Multilingual illustrated guide to the world’s commercial warmwater fish. Fishing News Books, Osney Mead, Oxford, England.
8. Kottelat, M. and Freyhof, J. (2007) Handbook of European freshwater fishes. Publications Kottelat, Cornol and Freyhof, Berlin.
9. ICCAT (2009) Report of the standing committee on research and statistics (SCRS). Madrid, Spain.
10. Scientific, Technical and Economic Committee for Fisheries (STECF) (2014) The Economic Performance of the EU Aquaculture Sector (STECF 14-18) (Ed. Nielsen, R., Motova, A.), pp. 403. Publications Office of the European Union, Luxembourg, EUR XXXX EN, JRC XXXX, xxx pp.
11. PROteINSECT (2016) Insect Protein – Feed for the Future. [online] Minerva Communications UK Ltd. Available at: https://www.fera.co.uk/media/wysiwyg/our-science/proteinsect-whitepaper-2016.pdf [Accessed 19.10.2017].
12. Makkar, H.P.S., Tran, G., Heuzé, V., Ankers, P. (2014) State-of-the-art on use of insects as animal feed. Animal Feed Science and Technology, 197, 1-33.
13. Tran, G., Heuzé, V., Makkar, H.P.S. (2015) Insects in fish diets. Animal Frontiers. 5(2):37-44.

24 Oct 2017

Insects – the new animal feed in the EU

Written by scienceandmore
Category: Animal Biology

**Insects – the new animal feed in the EU**

24.10.2017 / Scienceandmore / Category: Animal Biology

Could insects be used to feed livestock and what would be the benefits to use insects compared to conventional animal feed?

This is the first of several consecutive articles that discuss the utilisation of insects as animal feed. Here, the legislative aspects for insects in the EU, animal feed in general, the use of insects for certain animals, and potential hazards are introduced.

Introduction

Livestock are of paramount importance for human diet and even though the proportions vary from country to country, on average around 95 % of the worldwide population eats meat (1).

In 2016, livestock that mainly consists of cows, pigs, poultry and shellfish/fish has been fed with more than one billion tons of feed. Approximately 44 % of the total animal feed was produced for poultry, followed by around 27 % for pigs, 22 % for cattle, and 4 % for animals in aquaculture (2).

Poultry, which is a generic term for mostly chickens, turkeys, quails, ducks and geese, is mainly fed with grains but also soy and fishmeal as a protein source. Pigs as omnivorous animals are also fed with grains, soy and fishmeal, as well as with oilseed meals, root crops and legumes. Cattle as herbivorous animals get grass and small amounts of grain and soy. Fish in aquaculture are mostly carnivorous, such as salmon and trout, and are commonly fed fishmeal in pellet form, but also soy, grains and legumes as cheaper protein and nutrient sources (3-6).

It is apparent that fishmeal and soy are crucial parts of animal feed. Approximately 16 to 17 million tons of wild fish (caught in the ocean) are processed into fishmeal and fish oil (including 5 million tons of fish trimmings) annually. The majority of this fishmeal and oil is used in aquacultures to rear fish for human consumption (6). However, prices for fishmeal have been risen due to high demand, especially since 2010/11, and in consequence to increased production of fish in aquacultures, farmers started to rely more on protein-rich plant-based materials for feed (6-8). The crops that are used are mainly imported from non-EU countries. In fact, only around 30 % of these crops are produced inside the EU and 70 % are imported from Brazil, Argentina and the USA. The import amounts to approximately 30 million tons annually, and soy is a major part of it. Significantly, 80% of the world’s soybean production is used as animal feed (6,7).

An alternative to fishmeal and soy could have been found in insect meal. Insects in general consist of approximately 40 to 60 % protein and up to 36 % of fat that could be fed separately as insect meal and insect oil (9). Insects are naturally eaten by cattle, pigs, poultry and fish as part of their species-appropriate diet (7). It is also not a new idea to use insects as a part of animal feed, specifically insect protein. However, in Europe during the 90s, there was a wide-ranging mad cow disease (bovine spongiform encephalopathy (BSE)) occurrence that was caused by feeding cows proteins from the remains of other cows, i.e. processed animal protein. Subsequently, almost all processed animal protein including insect protein was prohibited to be used as animal feed in the EU. An exemption was protein from fish.

Nevertheless, efforts were made to change EU legislation and finally on 1^st of July 2017, processed animal protein from insects was allowed to be used for animals in aquaculture (EU-enactment 2017/893) … however, only seven specific insect species received approval!

Before addressing the approved insect species, here are the most important arguments in favour of insects:

1) Insects meal can partly substitute for fishmeal and plant-based components in feed. Studies in livestock showed that insect meal could substitute fishmeal in feed to a certain degree (9). Fishmeal that is used to feed poultry, pigs and fish in aquaculture is produced from wild fish caught in the oceans. Using insect meal instead could therefore possibly prevent overfishing.

Plant-based components in fish feed have disadvantages compared to fishmeal, such as less palatability, anti-nutritional components, high fibre content, non-starch polysaccharides, and a different amino acid profile. Insects, on the contrary, are much lower in fibre and anti-nutritional content, and it has been proposed that they have a better suited amino acid profile than plant based components (10,11).

Since insect meal is only allowed to feed animals in aquaculture in the EU, the following article will focus on the utilisation of insect meal in this sector.

2) Insects require less space and energy for cultivation compared to soy. Soybean cultivation in the South American countries led to a drastic change in land use, most significant to a deforestation, as well as decreased soil fertility, ruined biodiversity and the use of tremendous amounts of water (6). Even though soy will most likely remain as one of the protein source in animal feed in the near future, insect protein could partly replace it. Consequently, the impact of soy cultivation on the environment could be reduced.

Compared to soybeans, insects are very efficient in utilising energy. Since they are cold-blooded, they do not expend energy to regulate their body temperature, so energy can be used for growth and development. A study showed that the production of 1 ton of crickets, which equals to around 600 kg of protein, requires around 2.8 tons of feed and a surface of 3,100 m². For soy, estimations suggest that the production of 1 ton, which equals to around 50 kg of protein, requires around 3,200 m² of land and takes one year (9,12,13). The life cycle of the cricket species Acheta domesticus on the other hand takes only two to three months! Obviously, the cricket feed/substrate also needs to be calculated in order to estimate if rearing crickets would be feasible, ecologically and economically. But that is the great aspect of insect cultivation… insects can feed on organic waste.

3) Insects have a broad range of substrates they can thrive on, such as food waste. In Germany, around 9.6 million tons, in Italy 5.7 million tons, in the UK 5 million tons, in France 3.7 million tons, and in all 28 EU member countries combined 31.2 million tons food waste were produced in 2014. This comprises animal and vegetable waste (14). This food waste could be used to rear insects and represents a cheap and even revenue-generating substrate. After rearing, the residual substrate could be used as fertiliser for crop production or as material to remediate soil, as it is still rich and accessible in nutrients and minerals. Investigations showed that the larvae of black soldier flies, one of the insect species that is approved for animal feed production, reduced the volume of organic waste by up to 60 % in just 10 days (7).

However, EU legislation does not allow the utilisation of food waste as substrate for insects that are meant for animal feed production (according to EG 999/2001 and EG 767/2009), due to the danger of a possible accumulation of chemicals and toxins in insects. These potentially hazardous substances could eventually accumulate in animals, generate allergens or, even worse, disease and would pose harm to the animals and humans upon consumption of the livestock.

4) Insects can be cultivated all year around. Most crop plants used for animal feed production are primarily cultivated in the field and are therefore seasonally restricted in their cultivation. Insects, however, can be reared all year around indoors. They would however require stable temperatures for optimal growth and development.

5) The use of insects as animal feed could lead to more independence from the import of raw material for animal feed production and result in a more stable market for animal feed in the EU. This is especially important since the demand of Asian countries for raw material continuously increases. Additionally, the American countries that are the major producers of soybeans are not liable to the strict regulations of GMO use of EU legislation (6,7).

Sometimes, implementing changes to improve handling of environmental and ecological issues can be motivated by financial gains. In 2014, 980 million tons of animal feed were produced, and in 2016 the production increased to over 1 billion tons worldwide, which translate to a value of approximately $460 billion (approximately €390 billion) (15,2), and makes the animal feed sector a lucrative sector for innovations. These numbers represent the whole animal feed sector but the changes in EU legislation only affect the aquaculture sector. Here, the production of animals in aquaculture increases constantly. In 2012, it already reached 1.108 million tons of animals with a commercial value of almost €3.4 billion in the EU alone (7). It has to be pointed out that the EU is the no. 1 fish importer worldwide, with imports valued at US$54 billion (approximately €45.6 billion) in 2014 (16). Similarly, feed for domestic animals in aquaculture is mostly imported as well (only 5.9 million tons of feed for these animals was produced in Europe itself in 2014) (15). Production of sustainable feed and rearing of greater numbers of animals in aquaculture in the EU could decrease the need to import them to satisfy domestic consumption.

References

1. FOE (2014) Meat Atlas – Facts and Figures About the Animals We Eat. [online] FOE Europe. Available at: https://www.foeeurope.org/sites/default/files/publications/foee_hbf_meatatlas_jan2014.pdf [Accessed 16.10.2017].
2. Alltech (2016) Global Feed Survey. [online] Alltech. Available at: https://go.alltech.com/alltech-feed-survey [Accessed 16.10.2017].
3. Food Standards Agency. What farm animals eat. [online] Food Standards Agency. Available at: https://www.food.gov.uk/business-industry/farmingfood/animalfeed/what-farm-animals-eat [Accessed 16.10.2017].
4. Lázaro, R., Mateos, G.G., Latorre, M.M., Javier, P. (2015) Whole soybeans in diets for poultry. American Soybean Association
5. McGlone, J., Pond, W.G. (2003) Pig production: biological principles and applications. pp. 191. Cengage Learning, NY, USA.
6. Stamer, A. (2015). Insect proteins – a new source for animal feed: The use of insect larvae to recycle food waste in high-quality protein for livestock and aquaculture feeds is held back largely owing to regulatory hurdles. EMBO Reports, 16(6), 676–80.
7. PROteINSECT (2016) Insect Protein – Feed for the Future. [online] Minerva Communications UK Ltd. Available at: https://www.fera.co.uk/media/wysiwyg/our-science/proteinsect-whitepaper-2016.pdf [Accessed 16.10.2017].
8. Van Huis, A., van Itterbeeck, J., Klunder, H., Mertens, E., Halloran, A., Muir, G., Vantomme, P. (2013) Edible insects: future prospects for food and feed security. FAO Forestry Paper 171: 89-97.
9. Makkar, H.P.S., Tran, G., Heuzé, V., Ankers, P. (2014) State-of-the-art on use of insects as animal feed. Animal Feed Science and Technology, 197, 1-33.
10. Sanchez-Muros, M.-J., F.G. Barroso, and F. Manzano-Agugliaro (2014) Insect meal as renewable source of food for animal feeding: A review. J. Clean. Prod. 65:16–27.
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