Scientific interest for insects for feed is growing

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Scientific interest for insects for feed is growing

Published on
September 11, 2018

More and more people are interested in the use of insects as animal feed or as animal feed ingredient. Insect products are allowed for use already in petfood and aquaculture. It is expected that EU-regulations will be adapted in the near future and thereafter insect products may also be used as feed material for poultry and pigs. Research is making progress and the number of papers on insects as mini-livestock increases rapidly as shown during a one-day symposium on “Insects for Feed” during the annual EAAP meeting.

For the second year, the new study commission on Insects of the European Federation of Animal Science organised a one-day symposium on “Insects for Feed” during the annual EAAP meeting in Dubrovnik, Croatia. Teun Veldkamp of Wageningen Livestock Research and president of the Insect commission of EAAP, noticed that symposia on insects attract more and more people. Earlier the world conference ‘Insects to Feed the World’ in Wuhan, China, attracted almost 300 participants from 40 countries, and the EAAP Insect Symposium attracted almost 100 delegates. The latter symposium included two sessions: ‘Cost effective insect production and high quality insects for feed’ and ‘Safety, regulatory issues and effects of insects in animal feed’.

Cost effective and high quality

Lars-Henrik Lau Heckmann presented three large projects currently conducted in Denmark. SUSMEAL, WICE, and inVALUABLE. The partners in these consortia span the entire value chain and include entrepreneurs, experts in biology (entomology and nutrition), biotech, automation, processing and food tech and -safety. This interaction of competences is key to lifting insect production to an industrial level. In summary, main findings by Heckmann confirmed that mealworms (Tenebrio molitor) are efficient converters of organic by-products and are suitable to use as feed and food ingredient. A sustainable pilot-scale mealworm production was presented; sustainable in terms of environment as well as economy. It is important to develop a cost effective diet of approved organic residues and waste products coming from the feed and food industries. Also the construction and operation of a pilot plant for the production of larvae of the type black soldier fly (Hermetia illucens) was presented.

Filip Wouters focussed on lowering production costs and upscaling of insect rearing by focusing on automation of the labour intensive tasks. An automated feeding line for mealworm was developed, enabling implementation of a strict feeding regime and monitoring. By this technique less space is required and minimal movement of the crates with the insects. Several sieving techniques were compared for both mealworm (Tenebrio molitor) and the black soldier fly (Hermetia illucens).

David Deruytter presented a method to predict the number of offspring in mealworms (Tenebrio molitor) based on the beetle density and or egg density in order to have a more efficient feeding regime and hence a faster growth and more revenue. Two different techniques were assessed to predict the final harvest. In conclusion, it is possible to determine the final harvest at a very early stage via the two presented techniques potentially resulting in more optimal feeding and growth.

Luciano Pinotti mentioned that the use of alternative feed ingredients in farm animal’s diet can be an interesting choice from several standpoints, even though their nutritional value, quality and safety should be always kept in mind. Among different alternative feed ingredients, insect based ingredients can be considered a hot topic. Insects are looked as an interesting alternative protein source for feed and are expected to be increasingly used in Europe as replacers for animal-derived proteins especially in aquaculture, even though their potential for other farm species and as fat sources, cannot be excluded. Insect species and life stages (larvae vs. pre-pupae vs. adult form) represent further sources of variation which could impact not only feed formulation, but also feed production. Different leftovers were presented that can be used to upgrade low value organic waste streams into high-value biomass.

Safety and regulatory issues

Safety aspects of substrates for insects and of insects for feed were discussed by Tarique Arsiwalla and Ine van der Fels. Only plant origin sources (pre consumer) and milk or egg products (strictly no meat, fish, manure or post-consumer organics) are allowed as substrates to produce insects. The use of insect protein is allowed in petfood and feed for aquaculture and insect lipids are allowed for all farmed animals as well as pet food. The insect producing sector is in favour of allowing the use of pre-consumer “former foodstuffs, including meat and fish” as substrate for rearing insects. Van der Fels presented results of recent safety studies on potential accumulation of different mycotoxins in black soldier flies and lesser mealworm larvae. In this study, substrate was used, that was artificially contaminated with four different mycotoxins (aflatoxin B1, deoxynivalenol (DON), ochratoxin A or zearalenone) and a mixture of these. Black soldier fly larvae and Lesser mealworm excreted or metabolized the four mycotoxins that were present in their substrate. The four mycotoxins do not seem to be a concern in insects considering current EC limits for mycotoxins in feed.

Annette N. Jensen presented the effect of starving and rinsing mealworms (Tenebrio molitor) at harvest aiming to empty their gut and presumably lower the microbial load for sanitary reasons. The microbial load was generally high (approx. 8 Log CFU/g), and neither starvation for 24 or 48 h, nor did rinsing with water seem to reduce the microbial load consistently in two independent trials (preliminary results). An apparent 1 Log CFU/g decrease (from 7 to 6 Log CFU/g) in the Enterobacteriaceae numbers after 24 h but not 48 h of starvation was not supported by the second trial. An attempt to reduce the microbial load by feeding with sterile feed substrate did also not reduce the microbial load in the larvae and the remaining substrate (frass) yielded high bacterial loads after the larval feeding. More knowledge about the dynamics between the inherent microbial composition of the larvae and the uptake of microbes from the feed substrate may gain insight on how to ensure the microbial quality of mealworm products.

Insects or insect products as feed or feed ingredient

Five presentations were given on the use of insects or insect products as feed or feed ingredient.

Laura Gasco considered insect products as a sustainable form of protein production. Insect-based proteins can partially replace conventional proteins in feeds for fish, poultry and pigs. Moreover, insects seems to be a promising source for bioactive substances (antimicrobial peptides, chitin, lauric acid) with pharmacological functions, able to modulate the animal microbial communities or to stimulate the immune response.

Johann Detilleux presented preliminary results on effects of feeding larvae of black soldier fly on poultry microbiota. New modifications were identified in the chicken phenotypes as gut microbiota composition varied. For example, indirect changes were observed in the average daily gain, feed conversion ratio, tibia ash percentage and abdominal fat score in relation with the introduction of larvae in the diet, changes mediated by the influence of the diet on the relative abundance of Bacillaceae. We suggested presence of Dysgonomonas in larvae and in the growing substrate (after the passage of BSF larvae) may be one of the mechanisms used by the larvae to transform manure because these bacteria have a fermentative metabolism producing acids and no gas.

Olga Moreira emphasised that insects such as the Black soldier fly should be used to convert organic residues to valuable products. The ENTOVALOR project is studying such conversions. The preliminary results will contribute to the selection of larvae rearing substrates based in agricultural by-products and to larvae efficient use as an alternative protein rich ingredient for the monogastric compound feed industry.

Kristy DiGiacomo performed in vitro rumen fermentation studies and suggested that black soldier fly larvae will have a different nutritional value for ruminants depending on the larvae rearing substrate.

Florian Leiber studied replacement of conventional protein sources by Black soldier fly in layers, broilers and trout. Performance of these animal species was not affected.

Next symposium August 2019

Next to theatre presentations also high quality posters were exposed on different insect species and expertise. The next EAAP Insect symposium will be at the 70th Annual EAAP meeting, which will be held in Ghent, Belgium from 26th to 30th August 2019.